Fast Pyrolysis of Dried Sugar Cane Vinasse at 400 and 500 Â°C

Subscriber access provided by Iowa State University | Library

Biofuels and Biomass

Fast pyrolysis of dried sugarcane vinasse at 400 and 500 °C: product distribution and yield Meheretu Jaleta Dirbeba, Atte Aho, Dr. Nikolai DeMartini, Anders Brink, Ida Mattsson, Leena Hupa, and Mikko Hupa Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.8b03757 • Publication Date (Web): 26 Dec 2018 Downloaded from http://pubs.acs.org on January 5, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

Fast pyrolysis of dried sugarcane vinasse at 400 and

2

500 °C: product distribution and yield

3

Meheretu Jaleta Dirbeba†,*, Atte Aho†, Nikolai DeMartini†, ‡, Anders Brink†, Ida Mattsson†,

4

Leena Hupa†, and Mikko Hupa†

5

†Johan

6

Turku, Finland

7

‡Chemical

8

Toronto, Ontario, M5S 3E5 Canada

9

ABSTRACT

10

Gadolin Process Chemistry Centre, Åbo Akademi University, Piispankatu 8, 20500

Engineering & Applied Chemistry, University of Toronto, 200 College Street,

Fast pyrolysis of sugarcane vinasse, a by-product from the integrated sugar-ethanol process,

11

has not been investigated so far. In this work, fast pyrolysis of dried sugarcane vinasse was

12

carried out at 400 and 500 °C in a drop-tube type N2-purged reactor, and the yields and

13

compositions of the oil, char, and gas were determined. The results show that the water-free bio-

14

oil yield was low and independent of the pyrolysis temperature. This is probably due to the high-

15

potassium content of the vinasse. For other biomass fuels, it is well established that alkali metals

16

catalyze secondary reactions in the vapor-phase of the pyrolysis product thereby reducing the

17

organic liquid yield and increasing the gas and water yields. The char yield decreased, and the 1

ACS Paragon Plus Environment

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

18

gas yield increased with temperature. Forty-five to fifty-five percent of the carbon in the vinasse

19

was retained in the chars. Thus, approximately half of the carbon in vinasse could be sequestered

20

if the chars are returned to the soil. Moreover, since over eighty-five percent of the potassium in

21

the vinasse was also retained in the chars, pyrolysis may be an interesting option for the

22

production of biochar with a high potassium content for fertilizer. The recovery of most of the

23

potassium with the chars indicates that the liquid and gaseous pyrolysis products could be burned

24

in a boiler with lower ash-related problems than the original vinasse.

25

KEYWORDS: Fast Pyrolysis; Vinasse; Bio-char; Bio-oil

26

1. INTRODUCTION

27

Bio-oil production through fast pyrolysis from biomasses has attracted interest due to several

28

advantages of the bio-oil compared to solid biomass fuels. These advantages of the bio-oil

29

include ease of storage and transportation, higher energy density, and versatile applications—

30

mainly production of energy and chemicals.1,2 Also, in contrast to liquid fossil fuels, the bio-oil is

31

carbon neutral and produced from renewable feedstocks. Consequently, efforts are underway to

32

develop large-scale technologies for fast pyrolysis. For example, the first industrial-scale fast

33

pyrolysis plant built integrated with a combined heat and power process is the Fortum Otso bio-

34

oil plant in Joensuu, Finland.3

35

Fast pyrolysis process is characterized by high heating rates and short residence times and

36

rapid cooling of the pyrolysis vapors with the target of maximizing the bio-oil yield.1,2,4–7 Reactor

37

configurations, such as bubbling fluidized bed and circulating fluidized bed, and finely ground

38

biomass particles, ≤ 3 mm,1,5 are among the key parameters to achieve high heat transfer and 2


Page 2 of 46

Page 3 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

39

heating rates in fast pyrolysis processes. The optimum temperature for high bio-oil yields is

40

usually around 500 °C1,5,8 although this temperature varies slightly based on the type and

41

composition of biomass. Moreover, the feedstock should be dried to a moisture content of ≤ 10

42

wt.% prior to pyrolysis to minimize the water content of the final bio-oil product.1,6

43

Vinasse, also known as stillage or spent wash, is a dilute effluent from the integrated sugar-

44

ethanol industry. Typically, the dry solids content of vinasse is only 5-10 wt.%.9 On a dry basis,

45

vinasse contains 60-70 wt.% organics with the balance being inorganics, and it has a heating

46

value in the range of 10-15 MJ/kg dry solids10 similar to that of black liquor solids from pulping

47

mills.11 Production of 1 m3 ethanol generates on average 10-15 m3 of wet vinasse.9,12 In Brazil

48

alone, the annual generation of vinasse is approximately 370 million cubic meter13 which is

49

equivalent to an average annual thermal energy supply of about 125 TWh. Today, vinasse is

50

mainly used for fertirrigation, providing the soil with water and at the same time fertilizing the

51

soil for sugarcane plants.14 However, its use as fertirrigation may have negative environmental

52

impacts depending on soil conditions and location, including emission of greenhouse gases15 and

53

pollution of soil and groundwater.14 In some cases, the amount of vinasse produced is greater

54

than the amount of vinasse that can economically be used as a fertilizer. This is because of the

55

cost of transporting it to farmlands farther away from the mill. Thus, there is a need for

56

alternative utilization options, such as fast pyrolysis.

57

Fast pyrolysis of various biomass types, including wood, agricultural by-products, energy

58

crops, and solid wastes have been intensively studied, and comprehensive review papers are

59

available.1,2 However, fast pyrolysis of sugarcane vinasse has not been investigated so far. Da

60

Silva et al.16 have studied thermal behaviors of vinasse and vinasse blended with other biomass

61

residues from the sugarcane industry under pyrolysis, combustion, and oxy-combustion 3


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

62

conditions. According to Da Silva et al., thermal decomposition of the organic fraction of vinasse

63

starts at as low temperature as 160 °C under all conditions.

64

Although it is beyond the scope of the present study, an important factor that needs to be

65

considered for the feasibility of vinasse fast pyrolysis processes is the energy required to

66

concentrate the dilute effluent to a higher solids content. Nevertheless, there are some options

67

that can potentially address the problem. One option is through heat integration in the sugar and

68

ethanol production processes. Recently, Cortes-Rodríguez et al.17 and Pina et al.18 have

69

demonstrated using modeling, simulation, and economic analysis that this option can reduce the

70

energy consumption of a sugar mill significantly. Moreover, the latter authors have also

71

suggested that water evaporated from the vinasse could be utilized, such as for imbibition or

72

cooling, in the mill thereby decreasing the water demand of the mill. Oasmaa et al.19 have also

73

conducted a techno-economic evaluation of an integrated biomass fast pyrolysis system over a

74

standalone process. Their evaluation suggested that the integrated process is economically more

75

competitive than the standalone. Another alternative is improving the energy efficiency of the

76

combined sugar, ethanol, and energy production process through technology upgrading.

77

Pellegrini and de Oliveira Junior20 have conducted thermal, economic, and environmental

78

analysis as well as optimization of this approach. They suggested that besides adding a new

79

revenue to the mill, this option generates excess electricity which improves the exergy and

80

environmental performance of the integrated process. In both cases, a part of the savings from the

81

reduction in energy consumption or the excess energy generated could be used for vinasse

82

concentration. It is also worth noting that companies such as Valmet21 have already shown

83

interest to concentrate vinasse to a high solids content for a thermochemical conversion.

4


Page 4 of 46

Page 5 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

84

Energy & Fuels

The objective of this work is to determine product distribution and yield (char, bio-oil, and

85

gas) during fast pyrolysis of dried sugarcane vinasse at 400 and 500 °C. The char and bio-oil

86

yields were determined gravimetrically, whereas the gas yield was calculated from measured gas

87

flow rates and CO, CO2, and SO2 concentrations. Fast pyrolysis of the vinasse in the temperature

88

range of 400-600 °C was studied using an N2-purged quartz-glass reactor, also referred to as,

89

single particle reactor (SPR), which is a simpler setup than the drop-tube type N2-purged reactor.

90

The water-soluble organic constituents of the vinasse were identified using solution-state nuclear

91

magnetic resonance (NMR) spectroscopy. The elemental compositions of the vinasse chars were

92

analyzed using a CHNS(O) analyzer and an inductively coupled plasma-optical emission

93

spectroscopy (ICP-OES). The CHNS(O) analyzer was also used to quantify the C, H, N, and S

94

contents of the pyrolysis oils. A Karl Fischer titration and a gas chromatograph–mass

95

spectrometer (GC-MS) setup enabled to determine the water contents and to identify the key

96

constituents of the pyrolysis oils, respectively.

97

2. EXPERIMENTAL SECTION

98

2.1.

99

Vinasse characterization The vinasse sample used in this work was obtained from a sugar mill in Ethiopia. The sample

100

was dried at the mill at 105 °C for 24 h, and it was ground to ≤ 1 mm size in the laboratory. A

101

further drying test was performed for the dried and ground vinasse. For the test, about 0.5-1 g of

102

the dried and ground vinasse sample was weighed and mixed with quartz sand as an inert surface

103

extender. Ultrapure water was added to the mixture for uniform dispersion of the vinasse over the

104

quartz sand particles. Then, the final mixture was dried at 105 °C for 24 h. The drying test 5


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

105

method was adopted from TAPPI/ANSI Test Method T 650 om-15, which is used for

106

determining the dry solids content of concentrated black liquor. The ash content, elemental

107

composition, and heating values of the vinasse from our previous work22,23 are provided in

108

section 3.1.

109

The vinasse was characterized for its organic components using solution-state NMR

110

spectroscopy. The 1H and 13C NMR spectra were recorded by Bruker Avance III HD 500 MHz

111

spectrometer (Germany) equipped with Bruker CryoProbe (Germany). Topspin software, version

112

3.5, was used to process the spectra. Prior to analysis, between 15 and 20 mg of the vinasse

113

sample was dissolved in approximately 1 ml of 99.9% deuterium oxide (D2O; Sigma-Aldrich).

114

The experiment was repeated three times to establish repeatability, and the results were reported

115

as plots of chemical shifts, δ (in ppm).

116

2.2.

117

Fast pyrolysis experiments in the drop-tube type N2-purged reactor 2.2.1.

Description of the experimental setup. Figure 1 shows a schematic drawing

118

of the fast pyrolysis experimental setup. The dashed lines in the figure show the connections used

119

during the experiments described in section 2.3. The heart of the setup is a drop-tube type N2-

120

purged reactor. It consists of three 80 mm inner diameter (i.d.) steel pipe segments: the pre-

121

heater, char holder, and pyrolyzer. The segments are 435, 160, and 525 mm long, respectively. A

122

stainless-steel wire mesh (mesh size = 150) was placed on a perforated steel plate and inserted

123

between the char holder and the pre-heater to retain the char in the char holder. Nitrogen (N2) gas

124

enters the preheater through a short 6 mm i.d. steel pipe for purging pyrolysis gas products from

125

the reactor. The steel pipe was fitted in the center of the bottom lid of the pre-heater, and it was

126

perforated along its length. The perforations allow an even distribution of the N2 gas in the 6


Page 6 of 46

Page 7 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

127

reactor. The N2 gas was fed to the pre-heater at a flow rate of 3 lN/min, and it was pre-heated

128

before entering the char bed.

129

The reactor was inserted in an electrically heated furnace (Carbolite, model VST 12/600,

130

England). The temperature of the reactor was controlled automatically to the desired point by

131

setting the furnace temperature. In addition to the temperature of the pre-heater, the temperature

132

inside the pyrolyzer was measured at three different locations: in the lower (char bed), middle

133

(above the char bed), and upper (close to the top lid) parts of the reactor. The four temperature

134

measurement locations are indicated in Figure 1 as TC-0, TC-1, TC-2, and TC-3, respectively.

135

The temperatures were measured using K-type thermocouples, and the data were logged with a

136

computer. The temperature in the char bed, TC-1, was the controlled reactor temperature. A plot

137

of the temperature profiles of TC-0, TC-1, TC-2, and TC-3 as a function of time (in minutes) for

138

typical experiments can be found in Figure S1 in the Supporting Information.

139

For sample feeding into the reactor from the top side, an air-tight feeding system was used. It

140

consists of a plastic bottle with a flexible hose connected to it. The flexible hose was then

141

connected to a vertical 23 mm i.d. steel pipe, which enters the reactor from the top lid and

142

extends a few centimeters into the reactor. The steel feed pipe was provided with an N2-gas

143

supply line for sample feeding in pulses. Short N2 pulses were used for the sample feeding.

144

A stainless-steel pipe (SST) on the top lid connects the pyrolyzer with the condenser line. The

145

oil and water vapor produced in the reactor were condensed in a series of three condensers, which

146

were cooled to -40 °C using a cryostat cooler (LAUDA, Germany). Each condenser was fitted

147

with an oil collector. Two cotton filters were installed after the third condenser to capture oil

148

aerosols, tiny oil droplets that were carried over with non-condensable gases.

7


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

149

The flow of non-condensable product exiting the cotton filter was split into two parts. One

150

part was mixed with air, oxidized at 900 °C in the quartz glass reactor, which was enclosed in an

151

electrically heated oven, and analyzed for CO2 by using a 4900 Continuous Emissions

152

Analyzer (Servomex, England). The other part was routed through an AO2020 Continuous

153

Emissions Analyzer (ABB, Germany) for CO, CO2, and SO2 analysis. The gas flow rates to the

154

quartz reactor and ABB gas analyzer were measured using rotameters, whereas the air flow rate

155

to the reactor was maintained at 2.41 lN/min. The air flow rate was in excess of the stoichiometric

156

amount of air required for complete conversion of carbon to CO2 in the small batch of feed

157

described in section 2.2.2. The mass flow controllers were from Bronkhorst (Holland).

158 159

Figure 1. Schematic drawing of the fast pyrolysis experimental setup in the drop-tube type N2-

160

purged reactor. 8


Page 8 of 46

Page 9 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

161

Energy & Fuels

2.2.2. Experimental conditions and procedures. The fast pyrolysis experiments in the drop-

162

tube type N2-purged reactor were carried out at two different temperatures: 400 and 500 °C. It

163

was not possible to feed the vinasse into the reactor at temperatures higher than 500 °C since

164

most of it remained stuck to the steel pipe feeding system. Once the desired temperature for

165

pyrolysis was reached, about 40 g of the sample was weighed in the feed bottle described above,

166

section 2.2.1. The sample was fed into the pyrolyzer in batches of about 8-10 g each. Injection of

167

the sample batch with short and pressurized N2 pulses disperses the finely ground sample, which

168

is rapidly heated while falling onto the char bed in a similar fashion as in a drop tube furnace

169

(DTF). In a DTF, fine biomass particle heating rates of 104-105 °C/s24 can be attained at reactor

170

temperatures of over 900 °C. In the present setup, however, a lower heating rate can be

171

anticipated due to the low temperature used. The pyrolysis vapor residence time in the reactor

172

was about 25-30 s, which is longer than the typical 0.5-5 s 25 range for fast pyrolysis. The

173

experiment was stopped when the CO and CO2 readings from the gas analyzers were close to

174

0.01%. The net sample weight fed to the pyrolyzer was determined by subtracting the weight of

175

sample left in the feeding system from the initial weight of the sample weighed in the plastic

176

bottle. Part of the sample was stuck to the walls of the steel pipe part of the feeding system,

177

which was exposed to a temperature of ≥ 100 °C near the upper part of the pyrolyzer. The sample

178

left in the feeding system was carefully recovered after each experiment and weighed. The

179

recovered sample was 100% dry. The pyrolysis experiment was repeated three times at both 400

180

and 500 °C. Table 1 lists the conditions for the six experiments.

9


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 46

181

Table 1

182

Conditions for the vinasse fast pyrolysis experiments in the drop-tube type N2-purged reactor. Net sample fed to the pyrolyzer (g)

Temperature Experiment No. (°C)

183 184

2.3.

Dry solids (g)

Moisture (g)

1

400

30.8

2.9

2

400

31.1

2.9

3

400

28.8

2.9

4

500

29.5

2.9

5

500

30.0

2.9

6

500

29.3

2.9

Fast pyrolysis experiments in the N2-purged SPR To obtain vinasse char yield trends with temperature, additional data were needed in the

185

temperature range 400-600 °C apart from the two temperatures used in the drop-tube type N2-

186

purged reactor. For this reason, samples of the dried and ground vinasse were pyrolyzed at 400,

187

450, 500, 550, and 600 °C in 100% N2 in the SPR given in Figure 1. In this case, the SPR was

188

used as a pyrolyzer with conditions similar to those of the drop-tube type N2-purged reactor when

189

it comes to heating rate and gas atmosphere. For this purpose, the gas connections indicated by

190

the dashed lines in Figure 1 were used. The non-condensable gas lines entering the SPR and ABB

191

gas analyzer from the cotton filters shown in the figure were plugged. The air supply line was

192

replaced with N2, and a part of the exhaust gas from the SPR was connected to the ABB gas

193

analyzer. The SPR has a manual sample insertion probe (not shown in Figure 1), which allows a 10


Page 11 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

194

sample to be held in a cold environment and then inserted, in 1-2 seconds, into the hot reactor.

195

Detailed descriptions of the SPR are available in Karlström et al.26 and Giuntoli et al.27 About

196

100-120 mg of the dried and ground vinasse was weighed in a sample holder made of quartz

197

glass and mounted on the sample insertion probe. Then, the sample was inserted from the cold

198

environment into the hot SPR and pyrolyzed until the CO and CO2 readings from the ABB gas

199

analyzer were 0.0%. A part of the exhaust gas from the SPR, in this case, was connected to the

200

ABB gas analyzer. After the pyrolysis was over, the probe was retracted to the cold environment,

201

and the char was quenched in N2. Finally, the sample holder with char in it was removed from the

202

probe and weighed to 0.1 mg accuracy. At each temperature, the pyrolysis experiment was

203

repeated three times. The pyrolysis vapor residence time in the SPR was approximately 4 s.

204

2.4.

205

Char, oil, and gas yield determinations 2.4.1. Char yield. For the char yield determination from the drop-tube type N2-purged

206

reactor, the reactor was first cooled down after pyrolysis. The reactor was purged with N2 during

207

cooling. The reactor was then dismantled, and the char was carefully recovered from the char

208

holder. The char recovered from the char holder was swollen and porous. Chars were also

209

recovered from the pyrolyzer walls and surfaces of the thermocouples. The total recovered char

210

was weighed to 0.1 mg accuracy, and the result was reported as char yield on a wt.% dry vinasse

211

basis.

212

For the char yield from the N2-purged SPR, the char weight was obtained from the weight

213

difference between the empty quartz-glass sample holder and the sample holder with char in it.

214

The obtained char weight was expressed on a wt.% dry vinasse basis. At each temperature, the

11


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

215

average value of the three experiments on a wt.% dry vinasse basis was reported as char yield

216

from the SPR.

217

2.4.2. Oil yield. To recover the oil after the experiments in the drop-tube type N2-purged

218

reactor, the temperature of the condensers was adjusted from -40 °C to 5 °C using the cryostat

219

cooler. Then, the cryostat cooler was stopped, and the oil collectors, condensers, condenser lines,

220

cotton filters, and SST connecting the pyrolyzer with the first-stage condenser were dismounted.

221

The oil yield was determined from the weight difference between the empty oil collectors,

222

condensers, condenser lines, cotton filters, and SST connecting the pyrolyzer with the first-stage

223

condenser and the weight with the oil contained in them. An analytical balance, BL 1500 S

224

(Sartorius, Canada), which has a capacity to weigh up to 1500 g with 0.01 g accuracy, was used

225

for the weighing. Most of the oil recovered from the oil collectors was from the first stage.

226

For the recovery of the oil left sticking on the top lid, the lid was thoroughly washed with

227

acetone, and the washing was collected into a glass tray. The acetone was allowed to evaporate

228

from the oil-acetone mixture over a period of approximately 15 days. The weight of oil recovered

229

from the top lid was then determined from the weight difference between the glass tray with oil in

230

it after acetone evaporation and the empty glass tray.

231

2.4.3. Gas yield. The total mass of carbon in the non-condensable gases released from the

232

sample during pyrolysis in the drop-tube type N2-purged reactor was calculated based on the CO2

233

concentration of the oxidized gas and the total gas flow from the pyrolyzer. The mass of carbon

234

released directly as CO+CO2 from pyrolysis of the sample was determined from the ABB CO

235

and CO2 concentration results and the total gas flow from the pyrolyzer. The difference between

236

the amount of carbon from the complete oxidation of the gases and that of carbon from the

237

CO+CO2 was assumed to be the amount of carbon from hydrocarbons, CxHy, in the non12


Page 12 of 46

Page 13 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

238

condensables. It was not possible with the current setup to determine the specific types of these

239

hydrocarbons present in the gases. It is assumed that methane (CH4) was the dominant

240

hydrocarbon. The assumption is based on the report by Bhattacharya et al.28 Their report

241

indicates that the main hydrocarbon (on mass basis) in the gaseous product during pyrolysis of

242

black liquor solids is CH4. The total sulfur released during pyrolysis was obtained by subtracting

243

the amount of sulfur in the char from the amount in vinasse. The total sulfur released was

244

assumed to be in the non-condensables as SO2 and H2S. The amount of SO2 in the non-

245

condensables was based on the gas analysis, whereas that of H2S was calculated based on the

246

difference between the total sulfur released and the sulfur released as SO2. Thus, the gas yield on

247

a wt.% dry vinasse basis was obtained from the sum of the amount of CO, CO2, CH4, SO2, and

248

H2S in the gas.

249

Moreover, the CO and CO2 concentrations in the gases released from the pyrolysis of the

250

dried and ground vinasse in the SPR, at the five different temperatures, were measured with the

251

ABB gas analyzer. This enabled to obtain the CO to CO+CO2 mass ratio as a function of

252

temperature and to compare the results with those from the drop-tube type N2-purged reactor.

253

2.5.

Elemental analyses of the pyrolysis chars and oils

254

The C, H, and N contents of the vinasse chars and oils from the experiments in the drop-tube

255

type N2-purged reactor were analyzed using a FLASH 2000 organic elemental analyzer (Thermo

256

Scientific, UK). The oxygen contents of the chars and sulfur in the bio-oils were also analyzed by

257

the organic elemental analyzer. To minimize the loss of volatile organic compounds in the

258

analyzer, the bio-oils collected from the oil collector of the first-stage condenser were adsorbed

259

on to an adsorbent, Chromosorb® W/AW (ThermoQuest Italia S.p.A, Italy), prior to analysis. In 13


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

260

addition, double sample holders, i.e., tin cups, were used. The adsorbent was first put in a tin cup.

261

Then, about 2 mg of the bio-oil was added on the adsorbent, and the tin cup was carefully folded.

262

The folded tin cup with the adsorbed bio-oil in it was put in a second tin cup which was also

263

carefully folded. For the oils collected from the condensers, top lid, and SST connecting the

264

pyrolyzer with the first-stage condenser, only double sample holders were used. The ash-forming

265

elements of the chars, except chloride (Cl), were analyzed by an Optima 5300 DV ICP-OES

266

(PerkinElmer, USA). Detailed descriptions of the experimental procedures for the elemental

267

analyses with the organic elemental analyzer and ICP-OES are given in Dirbeba et al.22

268

For Cl, about 0.2 g samples of the chars from the pyrolysis experiments in the drop-tube type

269

N2-purged reactor were leached overnight in 2 L ultrapure water and filtered with 45 μm syringe

270

filters. The aqueous solutions were then analyzed for Cl using ion chromatography (IC; Metrohm,

271

Switzerland). Details of the experimental procedures for the analysis of Cl with the IC are

272

available in Dirbeba et al.22

273

2.6.

Water content, chemical composition, and acidity of the bio-oils

274

The water contents of the pyrolysis oils from the oil collectors were analyzed using a 736 GP

275

Titrino (Metrohm, Switzerland) volumetric Karl Fischer titration setup. The commercial reagent

276

used was Apura® CombiTitrant 5 from Merck (Germany). HydranalTM - methanol dry from

277

Sigma Aldrich (Germany) was used as a solvent for the bio-oils.

278

The bio-oils obtained from the oil collector of the first-stage condenser were also analyzed by

279

a GC (model 6890N)-MS (model 5973Netwok) (Agilent Technologies, USA). The procedures

280

for the GC-MS analysis of the bio-oil were adopted from Aho et al.29 All the bio-oil samples

281

were diluted with methanol in the oil to methanol ratio of 2:3 prior to analysis with the GC-MS. 14


Page 14 of 46

Page 15 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

282

The GC-MS column used was a 50 m Agilent DB-Petro with an inner diameter of 0.2 mm and a

283

film thickness of 0.5 µm. Heating of the column was started at 40 °C, and it was first kept

284

isothermal for 10 min at this temperature. Thereafter, the temperature was raised to 75 °C at a

285

rate of 0.90 °C/min. When the temperature of the column reached 75 °C, a steeper 1.10 °C/min

286

ramp was applied until 120 °C. Finally, the temperature was raised from 120 °C to 200 °C with a

287

heating rate of 10 °C/min. The column was kept isothermal for 20 min after 200 °C was reached.

288

The inlet pressure of the column was 135 kPa, and the scanning range was 10-300 a.m.u. The

289

time for the applied solvent delay was 6 min. The response factors for all compounds were

290

assumed to be equal.

291

The total acid number (TAN), a measurement of acidity for bio-oils, is the amount of

292

potassium hydroxide (KOH) in mg needed to neutralize all the acids in 1 g of a bio-oil sample.

293

The TANs for the vinasse bio-oils were determined using an 888 Titrando (Metrohm,

294

Switzerland) potentiometric titration setup. The titration was carried out according to ASTM D

295

664. The titrant used was 0.1 M KOH (KOH in isopropanol) from Merck (Germany). The solvent

296

used for the bio-oils was prepared by mixing toluene, isopropanol, and ultrapure water in the

297

proportion of 500 ml, 495 ml, and 5 ml, respectively. Both the toluene and isopropanol were

298

HPLC grades from Fisher Scientific (UK). The reagent used for calibration of the titration setup

299

was 99.5% pure potassium hydrogen phthalate (KPH), also from Merck (Germany). First, the

300

titration setup was calibrated using the KPH as a titer. For the calibration, about 0.1-0.15 g of the

301

KPH was dissolved in 100 ml of ultrapure water, and the solution was titrated with the KOH.

302

Then, a blank titration was performed using 125 ml of the solvent for the bio-oils. Finally, bio-oil

303

samples weighing 0.1-1 g were titrated, and their TAN values were calculated using the data in

15


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

304

Table S1 and Eq. S1 found in the Supporting information. All the titration experiments were

305

repeated at least two times.

306

3. RESULTS AND DISCUSSION

307

3.1.

Chemical composition of the vinasse

308

The drying test result revealed that the dried and ground vinasse had a moisture content of 7.2

309

wt.%. The ash content, elemental composition, and heating values of the vinasse from Dirbeba et

310

al.22,23 are given in Table 2. As can be seen from the table, the dominant cationic ash-forming

311

elements in the vinasse are K and Ca, whereas Cl and S are the main anionic constituents.

312

Figure 2 shows the δ (ppm) plot of the 1H (upper-left corner figure) and 13C NMR spectra for

313

the vinasse solution. The NMR spectra show that polyolic compounds, such as glycerols (1H δ =

314

3.2-4.3 ppm, 13C δ = 61-73 ppm) as the major water-soluble organic fraction of the vinasse. The

315

main organic acid identified by the NMR spectrometer was lactic acid (1H δ = 1.37 and 4.19 ppm,

316

13C

317

proteins, aromatic groups, and acetic acid can be observed as well. No ethanol is visible from the

318

NMR spectra possibly due to the sample treatment (drying at 105 °C).

319

= 20.3, 68.3, and 182.5 ppm). As seen in the figure, some residual traces of carbohydrates,

The polyols, organic acids, and aromatics are most likely from ethanol fermentation by-

320

products, while the carbohydrates are from unfermented sugars present in the vinasse. The

321

proteins are probably from proteinaceous compounds that are naturally present in sugarcane

322

juice, nutrients including urea (CO(NH2)2) and diammonium phosphate ((NH4)2HPO4) added for

323

yeast propagation, and/or residual microbial mass (yeast cells) left in the liquid fermentation

324

product after centrifugation. The compounds detected by the NMR spectrometer agree with the 16


Page 16 of 46

Page 17 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

325

reports that the major water-soluble organic fractions of sugarcane vinasse are organic acids,

326

glycerols, sugars, proteins, and ethanol.30–33

17


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

327

Table 2

328

Ash content, elemental composition, and heating values of dry vinasse. Elemental composition (wt.%)

Ash content (wt.%) 34.1±0.1

329

a Data

Page 18 of 46

Heating value (MJ/kg)a

C

H

N

O

K

Na

Ca

Mg

Si

Fe

P

S

Cla

HHV

32.9±0.3

4.5±0.04

1.0±0.01

36.4±0.5

14.1±0.2

0.4±0.01

3.2±0.1

0.6±0.01

0.6±0.1

0.1±0.01

0.1±0.1

2.7±0.1

6.2±0.3

14.0±0.2

are from Dirbeba et al.23 Standard deviations were calculated based on three determinations.

18


LHV 13.0±0.2

Page 19 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

330 331

Figure 2. 1H (upper-left corner figure) and 13C NMR spectra of the vinasse solution.

332

3.2.

Pyrolysis mass balance

333

Table 3 shows the pyrolysis mass balance on a wt.% dry vinasse basis for the experiments

334

carried out in the drop-tube type N2-purged reactor at 400 and 500 °C. The total amount of oil

335

was obtained by subtracting the amount of moisture contained in the feed from the total amount

336

of oil obtained from the oil collectors and condensers. The water-free oil, given as organics in the

337

table, were obtained by subtracting the water formed by pyrolysis, given as pyrolysis water in the

338

table, from the total amount of oil. The values for the pyrolysis water were calculated based on 19


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

339

the analyzed and average water contents of the bio-oils and the amounts of pyrolysis liquids

340

produced. Details of the calculations are given section 3.5.1. The values for the chars include the

341

inorganics. The “balance” mass is probably due to the mass of soot and oil left sticking on the

342

thermocouples and the internal surface of the reactor.

343

Table 3 reveals that about 45-55% of the total oil was recovered from the oil collectors and

344

condensers, and approximately 25-35% was trapped in the cotton filters as oil aerosols. The oil

345

recovered from the other units, given as “others” in the table, accounts for 15-20% of the total.

346

Moreover, the results in the table show that about 88%, 5%, and 2% of the gaseous pyrolysis

347

product at 400 °C are CO2, CO, and CxHy, respectively. The corresponding numbers for the

348

gaseous species at 500 °C are 76% CO2, 9% CO, and 11% CxHy.

20


Page 20 of 46

Page 21 of 46 1 2 349 3 4 5 350 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 351 22 23 24 352 25 26 353 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Energy & Fuels

Table 3 Pyrolysis mass balance (wt.% vinasse, dry basis). Pyrolysis liquids Experiment No.

Gases

Chars

Balance Collectors

Condensers

Othersa

Filters

Moisture with vinasse

Pyrolysis water

Organics

Totalb

CO

CO2

SO2

CxHy

H2S

Total

1

400

51.3

7.1

12.0

3.2

4.6

9.4

5.4

12.1

17.5

1.0

15.6

0.3

0.3

0.6

17.8

13.4

2

400

53.7

12.9

3.9

3.9

5.8

9.3

5.9

11.3

17.2

1.0

15.8

0.2

0.3

0.6

17.9

11.2

3

400

51.7

8.0

8.3

3.8

7.3

10.1

4.6

12.7

17.3

0.7

13.9

0.2

0.3

0.7

15.8

15.2

4

500

49.5

8.1

11.2

4.1

4.4

9.8

5.8

12.2

18.0

1.7

15.6

0.3

1.7

0.7

20.0

12.5

5

500

47.7

13.7

6.3

2.3

7.3

9.7

8.6

11.3

19.9

1.7

15.0

0.3

2.7

0.3

20.0

12.4

6

500

47.4

11.9

6.8

3.1

8.2

9.9

7.3

12.8

20.1

1.7

14.7

0.3

2.4

0.3

19.4

13.1

a Includes b

Temperature (°C)

oil collected from the top lid, SST connecting the pyrolyzer to the first condenser, and silicon tubes connecting the condensers.

The amount of moisture in the vinasse fed to the reactor was subtracted from the sum of the amounts of oil collected from the oil collectors and condensers to obtain the total oil produced.

21


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

354 355

3.3.

Pyrolysis product yields Figure 3 shows the average char, oil (water-free), pyrolysis water, and gas yields on a wt.%

356

dry vinasse basis at 400 and 500 °C from the drop-tube type N2-purged reactor. The average

357

values for the yields were calculated from the results given in Table 3. The char yields, given in

358

the figure, include the amount of ash (inorganics) in the chars, whereas the oil yields are given on

359

water-free basis.

360

It can be seen from Figure 3 that the char yield decreased by 4 wt.% as the temperature was

361

increased from 400 °C to 500 °C, while the gas yield increased by 2.6 wt.%. The decrease in char

362

yield and increase in gas yield with temperature are similar with the char and gas yield trends

363

with temperature found in the literature for woody biomasses5,8,34–36 and agricultural biomass

364

residues.37–40 These trends are ascribed to the increased decomposition of the organic fraction of

365

biomass at higher temperatures.

366

The water-free bio-oil (liquid organics) yield, given in Figure 3, is almost independent of

367

temperature, while the pyrolysis water yield increased by about 2 wt.% when the temperature was

368

increased from 400 °C to 500 °C. The organic liquid yield results are rather low compared to the

369

typical 30-70% yields reported in the literature for woody biomasses and agricultural biomass

370

residues.41 High levels of inorganics in the vinasse, especially alkali metals, may be the cause for

371

the low oil yield results in this work. According to the studies by Oasmaa et al.19 and Fahmi et

372

al.,42 biomass fast pyrolysis product yields strongly correlate with the level of inorganics in the

373

biomasses. These authors have reported organic liquid yields, on a wt.% dry biomass basis, of 55-

374

65 for biomasses yielding ≤ 1 wt.% ash and 25-40 for agricultural biomass residues which

375

produce 4-6 wt.% ash. In particular, Coulson43 and Aho et al.29 have reported a reduction in 22


Page 22 of 46

Page 23 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

376

pyrolysis organic liquid yields of about 15-20 on a wt.% dry fuel basis with an increase of about

377

0.3-0.7 wt.% fuel, dry basis, in the concentration of alkali metals in biomass fuels. Alkali metals

378

in biomass fuels are known to catalyze secondary reactions in the vapor-phase of the pyrolysis

379

product thereby reducing the organic liquid yield and increasing the gas and water yields.

380

Serikawa et al.44 reported a maximum bio-oil yield of 24.5 wt.% vinasse, dry basis, for a high-

381

pressure-hydrothermal liquefaction of vinasse at 300 °C in a bomb-type batch reactor. However,

382

potassium recovery from such processes is challenging as most of the potassium in the vinasse is

383

water soluble.

384

Figure 4 shows the char yield results from the fast pyrolysis experiments carried out in the

385

N2-purged SPR. For comparison, the char yield results from the drop-tube type N2-purged reactor

386

are also given in the figure. Here too, the results from the SPR show that the char yield decreases

387

with temperature in the temperature range of 400-600 °C. Moreover, the good agreement in the

388

char yield results from the two reactors indicates that similar pyrolysis heating rates were attained

389

in both reactors. It is well established that char yield during biomass fast pyrolysis decreases with

390

increasing heating rate, and vice versa.

23


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

391 392

Figure 3. Vinasse fast pyrolysis product yields from the drop-tube type N2-purged reactor. Error

393

bars are standard deviations calculated based on results from the experiments repeated three times

394

at each temperature.

24


Page 24 of 46

Page 25 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

395 396

Figure 4. Char yields from the N2-purged SPR and drop-tube type N2-purged reactor. Error bars

397

are standard deviations calculated based on results from the experiments repeated three times at

398

each temperature.

399

3.4.

400

Analyses of the pyrolysis chars Table 4 shows elemental analysis results of the vinasse chars produced at 400 and 500 °C in

401

the drop-tube type N2-purged reactor on a wt.% char basis. Each value given in the table is the

402

average value of analyzed chars from the three repeated pyrolysis experiments. There are large

403

deviations in the iron results of the chars given in the table probably due to contamination of the

404

chars with iron from the reactor.

25


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

405

Based on the results of the char yields and elemental analysis and the vinasse elemental

406

composition given in Table 2, it is possible to calculate the levels of inorganics released from the

407

vinasse during pyrolysis. The release levels were 12-13% of the K, 30-33% of the S, and 24-29%

408

of the Cl in the vinasse at both temperatures. The retention of most of the K in the chars has an

409

important practical implication: pyrolysis may be an interesting option for the recovery of K from

410

vinasse for fertilizer. For the K in the chars to be utilized for fertilizer, it has to be in a form

411

available to plants. Bioavailability of K, which refers to the uptake of K by plants,45 is influenced

412

by, among others, the ease of its mobility in soil. Generally, water-soluble forms of K, such as

413

KCl, are mobile in moist soils and hence are readily bioavailable. All of the K in the chars

414

produced at 400 and 500 °C are water soluble. This was verified by leaching samples of the chars

415

in water overnight and filtering with 45 μm syringe filters. The aqueous solutions were analyzed

416

for K using the ICP-OES described in section 2.5. The ICP-OES results showed that all the K in

417

the chars were dissolved in water.

418

In addition to the recovery of K for fertilizer, application of the biochar to the soil has been

419

shown as a viable option for carbon sequestration.46 Based on the char yields and the results

420

given in Tables 2 and 4, it can be calculated that about 45-55% of carbon in the vinasse was

421

retained in the chars produced at 400 and 500 °C. Thus, returning the chars to the soil would

422

sequester approximately 50% of the carbon in the vinasse that would otherwise contribute to

423

GHG emission. Moreover, according to the study by Sadeghi et al.,47 application of biochars

424

produced from vinasse to soil reduces soil runoff and loss. Also, Houben et al.48 have reported

425

that biochar application to contaminated soils with toxic metals reduces the concentrations of the

426

metals in plants.

26


Page 26 of 46

Page 27 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

427

Energy & Fuels

The retention of most of the K in the char further suggests that the bio-oil and gaseous

428

pyrolysis products could be burned in a boiler with lower ash-related problems to produce steam

429

than burning the vinasse directly. The ash-related boiler problems arising from the combustion of

430

biomass fuels with high levels of alkali metals are ash deposition, fouling, slagging, sintering,

431

agglomeration, and corrosion.49

27


Energy & Fuels 1 2 3 432 4 5 433 6 7 8 9 10 11 12 13 14 15 16 434 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Page 28 of 46

Table 4 Elemental composition of the vinasse chars produced in the drop-tube type N2-purged reactor at 400 and 500 °C (wt.% char). Temperature (°C)

C

H

N

O

K

Na

Ca

Mg

Si

Fe

P

S

Cl

400

33.8±2.3

2.1±0.1

1.1±0.1

20.0±0.1

23.7±0.6

0.6±0.0

5.3±0.2

1.0±0.0

2.3±0.1

0.9±0.6

0.2±0.0

3.5±0.5

9.0±0.4

500

31.4±1.8

1.1±0.1

1.0±0.1

19.6±1.2

25.6±1.3

0.6±0.0

5.8±0.3

0.9±0.1

2.5±0.1

1.1±1.2

0.2±0.0

3.8±0.6

9.1±0.2

Standard deviations were calculated based on results from the experiments repeated three times at each temperature.

28


Page 29 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

435 436

Energy & Fuels

3.5.

Analyses of the pyrolysis oils 3.5.1. Water contents. The water content of the bio-oils from the first-stage oil collector for

437

the vinasse oils produced at 400 and 500 °C was 90±3 wt.% oil. For the oils produced at either

438

400 or 500 °C and collected from the second-stage and third-stage oil collectors, the amounts

439

were not enough to carry out the Karl Fischer titration. The analyzed water content includes

440

moisture evaporated from the vinasse sample.

441

Average water contents of the bio-oils, including moisture from the vinasse, were calculated

442

based on the analyzed water content of the oils, amounts of oils produced, and the following

443

experimental observations:

444

(a)

445 446

and the first-stage condenser are dominantly organics; (b)

447 448 449

The bio-oils recovered from the top lid, silicon tubes, and SST connecting the pyrolyzer

At least half of the oils collected from first-stage condenser wall and one-third of the oils from the second-stage and third-stage condenser walls can be assumed to be water-free;

(c)

At least about 80% of the oil aerosols from the cotton filters are organics.

The observations in (a) and (b) were after following the procedures given in section 2.4.2 for

450

the recovery of oils from the top lid. After evaporation of the acetone from the acetone-oil

451

mixture, the oils from the top lid, silicon tubes, and SST connecting the pyrolyzer and the first-

452

stage condenser appear water-free, and no oil weight loss was observed. However, about 50% of

453

the oil from the first-stage condenser and only about one-third of the oils from the second-stage

454

and third-stage condensers were left after evaporation of the acetone. This method may

455

overestimate the water content of the oils from the condenser walls, top lid, silicon tubes, and

456

SST connection line due to evaporation of light organic compounds with the acetone. The 29


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

457

observation in (c) was verified by drying the cotton filters with oils in them at 105 °C for 24 h.

458

The weight of the filters after drying was decreased by only about 20% indicating that the oils

459

from the cotton filters were mainly organics. Again, this method may also over-approximate the

460

water content of the oil aerosols since a part of the oil weight loss may be due to volatilization of

461

light oils.

462

Thus, the average water contents of the bio-oils produced at 400 °C were 55.0, 57.4, and 53.6

463

wt.% for the oils from experiments 1, 2, and 3, respectively. The corresponding values for the

464

bio-oils produced at 500 °C were 56.1, 61.8, and 57.3 wt.%, respectively. The water formed by

465

pyrolysis, also known as, pyrolysis water can be obtained from the above-calculated average

466

water contents of the bio-oils and the results given in Table 3 by excluding moisture from the

467

vinasse. The calculation yields values of 5.4, 5.9, and 4.6 on a wt.% dry vinasse basis for the oils

468

from experiments 1, 2, and 3, respectively. The corresponding pyrolysis water values for the bio-

469

oils from experiments 4, 5, and 6 are 5.8, 8.6, and 7.3, respectively. The water contents of the bio-

470

oils are higher than the 15-30 wt.% oil50 range reported in the literature for bio-oils produced

471

from different biomass feedstocks.

472

3.5.2. Elemental composition. Table 5 lists the C, H, N, and S analysis results on a wt.% oil

473

basis for the oils collected from the condensers, top lid, and SST line connecting the pyrolyzer to

474

the first condenser. The results are for the part of oils remained after evaporation of the acetone

475

used for the recovery of the oils. The reported results are average values of the analyzed oils from

476

the three repeated pyrolysis runs. The C and H contents of the bio-oils from these different units

477

are in the same range indicating that only high-molecular-weight organics remained after

478

evaporation of the acetone. In addition, it can be seen from the table that the N and S contents of

479

the bio-oils increased with temperature. The C and H results of the bio-oils are in the same range 30


Page 30 of 46

Page 31 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

480

with the literature data for woody biomasses1,34,51 and agricultural biomass residues.40 The

481

presence of N in the vinasse oils is consistent with the GC-MS analysis results discussed in

482

section 3.5.3. The C, H, N, and S analysis results for the oils collected from the first-stage oil

483

collector were not reported because the results were unreliable. This was due to the high water

484

content of the oils. During analysis of these oils, condensation of water vapors on the gas transfer

485

line between the combustion chamber and detector of the analyzer was observed, indicating that

486

only a fraction of the gas was able to reach the detector.

487

Table 5

488

C, H, N, and S analysis results of the bio-oils collected from the condensers, top lid, and SST

489

connection line (wt.% oil, water-free basis). Temperature

1st stage oil

2nd stage oil

3rd stage oil

condenser

condenser

condenser

Elements (°C)

SSTa Top lid connection line

C

65.3±0.7

58.1±0.1

61.2±6.0

56.4±8.0

52.6±7.0

H

8.1±0.1

8.2±0.04

8.2±0.1

7.3±0.4

7.9±0.3

N

3.0±0.1

2.5±0.3

2.4±0.1

3.0±0.5

2.9±0.8

S

0.9±0.6

0.6±0.2

0.5±0.2

0.4±0.1

0.7±0.5

C

61.1±0.3

62.8±1.6

60.5±1.8

n/a

58.9±1.4

H

7.8±0.1

7.9±0.1

7.9±0.03

n/a

7.6±0.1

N

4.5±0.1

3.1±0.04

3.0±0.01

n/a

3.8±0.1

S

3.9±0.3

1.8±0.2

1.5±0.1

n/a

1.4±0.1

400

500

490 491

a Stainless

steel pipe. n/a = not analyzed. Standard deviations were calculated based on results from

the experiments repeated three times at each temperature.

31


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

492

Based on the elemental analysis results given in Table 5 and the correlation available in

493

Channiwala and Parikh,52 the HHVs of the bio-oils left in the condensers, top lid, and SST line

494

after acetone evaporation can be estimated. For the calculation, the ash contents of the bio-oils

495

were considered negligible. The calculation yields HHVs of 25-30 MJ/kg for the oils from these

496

units. In practice, however, the average HHVs of the vinasse oils will be lower than this range

497

due to their water contents. Nevertheless, the calculated HHVs provide the information that the

498

bio-oils can be burned in a boiler to generate heat and power.

499

3.5.3. Chemical composition. The level of oil weight lost during evaporation of acetone from

500

the oil-acetone mixture indicates differences in the molecular composition of the bio-oils

501

collected from the different parts. No weight loss was observed from the oils collected from the

502

top lid, SST line, and silicon tubes, while less oil weight was lost from the first stage than the

503

second or the third. This trend shows the following order in the molar mass of the organics

504

comprising the oils collected from the various parts: top lid or SST line > fist-stage condenser >

505

second-stage or third-stage condenser.

506

Table 6 lists the most dominant compounds found in the bio-oils from the first-stage oil

507

collector along with their relative peak areas detected by the GC-MS. The results show that the

508

bio-oils are composed of degradation products from the vinasse organic constituents identified by

509

the NMR spectrometer and discussed in section 3.1. The butanediols, cyclopentenones,

510

cyclopentanones, and phenols are probably from the sugars, whereas the N-containing

511

compounds, such as methylated pyridine, are probably from the proteins. It can be observed from

512

the table that some of the molecules including benzenediols that are present in the bio-oils

513

produced at 400 °C were not detected in the oils produced at 500 °C. This may be due to

32


Page 32 of 46

Page 33 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

514

fragmentation of these compounds at 500 °C to smaller molecules or non-condensable gaseous

515

products.

516

3.5.4. Acidity. The TAN values for the bio-oils produced at both 400 and 500 °C and

517

recovered from the first-stage oil collectors were in the range of 15-20. For the bio-oils produced

518

at both temperatures, recovered from the condenser walls and SST transfer line, and left after

519

evaporation of the acetone used for the recovery of the oils, the TAN values ranged from 85-125.

520

The latter values are close to the typical 50-100 53 TAN values for bio-oils from other biomasses.

521

However, the TAN values for the oils collected from the first-stage oil collectors were lower than

522

the typical range in the literature for bio-oils from other biomass fuels mainly because the vinasse

523

oils from the oil collectors were comprised of dominantly water.

33


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 46

524

Table 6

525 526

Most dominant compounds found in the bio-oils from the first-stage oil collector along with their relative peak areas detected by the GC-MS. Peak area (%)

Compound

400 °C

2,3-Butanediol 2-Cyclopenten-1-one 2-Cyclopenten-1-one, 2-methyl2(5H)-Furanone, 3-methylDianhydromannitol Butyrolactone Phenol Phenol, 2-methoxy2-Cyclopenten-1-one, 3-methylCyclopentanone 2-Cyclopenten-1-one, 2-hydroxy-3-methylCyclopentanone, 2-methylEthanone, 1-(2-furanyl)2-Cyclopenten-1-one, 2,3-dimethylPyridine, 2-methylPhenol, 2,4-dimethylPhenol, 2,6-dimethoxy1,6:2,3-Dianhydro-4-O-acetyl-.beta.-d-gulopyranose 3,5-Dimethyl Cyclopentenolone 2-Cyclopenten-1-one, 3,4-dimethyl2(3H)-Furanone, dihydro2(3H)-Furanone, dihydro-5-methyl2-Furanmethanol 2,5-Dimethyl-2-cyclopentenone 2-Cyclohexen-1-one Phenol, 4-methylCycloopent-2-ene-1-one, 2,3,4-trimethylPhenol, 2-methyl2-Cyclopenten-1-one, 3-ethyl-2-hydroxyCyclopentanone, 3-methyl2-Cyclopenten-1-one, 2,3-dimethyl2-Furancarboxaldehyde 2(3H)-Furanone, dihydro-3-methyl2R-2-(t-Butyl)-6-(trifluoromethyl)-2H,4H-1,3-dioxin-4-one 1,4-Benzenediol Pyridine, 2-ethylPyridine, 2,6-dimethylPhenol, 4-ethyl2,5-Dimethyl-2-cyclopentenone 2(3H)-Furanone, 5-methylEthanone,1-(1-cyclohexen-1-yl)Ethanone, 1-(2-methyl-1-cyclopenten-1-yl)3-Butene-1,2-diol Pyridine, 3,4-dimethyl4-Methyl-5H-furan-2-one Pyrazine, 2,6-dimethyl1,2-Benzenediol 1,2-Benzenediol, 3-methoxyCyclohexane, 1,2-dimethyl2-methoxy-4-propyl-phenol Cyclohexane, propyl1,3-Pentadiene,2-methyl2-Propanone,1-hydroxy-

527

500 °C 17.2 11.8 5.9 4.5 4.2 3.6 3.4 3.2 2.8 2.8 2.4 2.3 2.3 2.1 2.1 ND 2.1 1.7 1.6 1.5 ND 1.5 1.4 1.4 1.4 1.4 1.3 1.1 1.0 1.0 0.9 0.9 0.9 0.9 0.7 0.6 0.6 0.6 0.5 0.5 ND 0.5 0.5 0.5 0.4 0.4 0.4 0.3 0.3 0.3 0.3 ND ND

ND: not detected. 34


22.9 9.1 7.8 3.4 3.3 ND 3.2 1.3 4.9 3.5 1.8 2.5 3.0 4.8 3.1 0.4 0.6 ND 1.0 1.7 3.8 1.4 5.3 1.4 1.0 1.3 ND 1.3 0.5 1.8 ND ND 0.8 ND ND ND ND ND ND ND 0.8 0.5 ND ND ND 0.6 ND ND ND ND ND 0.8 0.4

Page 35 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

528 529

Energy & Fuels

3.6.

Analyses of the pyrolysis gases Figure 5 shows CO/(CO+CO2) mass ratio as a function of temperature for the pyrolysis

530

experiments performed in the N2-purged SPR. For comparison, CO/(CO+CO2) ratio results from

531

the experiments carried out in the drop-tube type N2-purged reactor are also included in the

532

figure. The results from the two reactors show that the dominant component in the gaseous

533

vinasse fast pyrolysis product is CO2. The high level of CO2 in the gaseous product is probably

534

due to the decomposition of low molecular weight organic compounds present in vinasse. The

535

low molecular weight organic compounds, i.e., glycerols and organic acids, which were identified

536

by the NMR spectrometer, contain weak functional groups, including carboxyl groups. These

537

functional groups are easily cleaved, releasing CO2 as the main gas component. A similar case

538

was reported by Bhattacharya et al.28 for pyrolysis of black liquor solids. In addition to the

539

decomposition of organic compounds with weak functional groups, the catalytic effect of the

540

inorganics in the vinasse, discussed in section 3.3, might have also enhanced the conversion of

541

pyrolysis vapors to CO2. Moreover, the results in Table 3 and/or in Figure 5 show that the CO

542

and CxHy levels in the gaseous product increased with temperature.

543

The increase in CO and CxHy levels in the pyrolysis gases with temperature increases the

544

heating value of the gases from approximately 1.5 MJ/kg at 400 °C to about 5-8 MJ/kg at 500 °C.

545

This is just based on the assumption that CO and CH4 are the main energy carriers in the gaseous

546

pyrolysis product with LHVs of 10.1 and 50.1 MJ/kg, respectively. The heating value of the

547

pyrolysis gases would be higher than the estimated values at both temperatures when H2

548

concentration, however low it is, in the gases is considered. Moreover, it can be inferred from

549

Figure 5 that the heating value of the pyrolysis gases can be significantly improved at 35


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

550

temperatures above 500 °C as a result of the increased CO concentration in the gases. However,

551

raising the pyrolysis temperature above 500 °C will be disadvantageous from the perspective of

552

potassium recovery as pyrolysis at higher temperatures favors the release of ash-forming matters,

553

especially alkalis and alkali chlorides, from the vinasse.22 Nevertheless, the vinasse fast pyrolysis

554

gases can be co-combusted in a boiler with other solid fuels, such as bagasse, in the integrated

555

sugar-ethanol process.

556

One important point worth noting from the good agreement of CO/(CO+CO2) results, given

557

in Figure 5, from the two reactors is the influence of residence time of the pyrolysis vapours on

558

the fast pyrolysis product distribution. The residence time of pyrolysis vapours in the drop-tube

559

type N2-purged reactor was about 5-6 times longer than in the SPR. Generally, the longer the

560

residence time of pyrolysis vapours in a reactor, the higher the chance of CO converting to CO2

561

due to secondary reactions in the vapor phase. Consequently, the drop-tube type N2-purged

562

reactor was expected to yield less CO concentration in the pyrolysis gases than the SPR.

563

However, similar levels of CO concentration in the pyrolysis gases were obtained from both

564

reactors at 400 °C or 500 °C. A similar observation can be made from Figures 3 and 4 where the

565

longer residence time of pyrolysis vapours in the drop-tube type N2-purged reactor would have

566

produced higher char yields than those obtained from the SPR. However, the char yield results

567

from the two reactors at 400 °C or 500 °C were approximately the same. The similar levels of CO

568

concentrations and char yields obtained from the two reactors indicate that differences in the

569

residence time of pyrolysis vapours in the reactors had little or no effect on the pyrolysis product

570

distribution. This further strengthens the suggestion that the alkali content of the vinasse may be

571

the controlling factor for the vinasse fast pyrolysis product distribution.

36


Page 36 of 46

Page 37 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

572 573

Figure 5. CO/(CO+CO2) mass ratio as a function of temperature for vinasse fast pyrolysis in the

574

N2-purged SPR and drop-tube type N2-purged reactor. Error bars are standard deviations

575

calculated based on results from the experiments repeated three times at each temperature.

576

4. CONCLUSIONS

577

In this study, product distribution and yield during fast pyrolysis of dried sugarcane vinasse at

578

400 and 500 °C in a drop-tube type N2-purged reactor were determined. The findings of the study

579

indicate that fast pyrolysis of vinasse for bio-oil production is not a good option. However, fast

580

pyrolysis might be an excellent means to produce potassium-lean pyrolysis oils and gases that

581

can be burned in a boiler while returning about half of the carbon and most of the potassium to

37


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

582

the land with the char. This would allow for energy to be recovered from the vinasse while

583

reducing some of the limitations of applying wet vinasse to agricultural lands.

584

ASSOCIATED CONTENT

585

Supporting Information

586

Figure S1. Temperature profiles of the pre-heater and three reactor zones of the drop-tube type

587

N2-purged reactor as a function of time.

588

Table S1. Potentiometric titration experimental data for the determination of TANs for vinasse

589

fast pyrolysis oils.

590

AUTHOR INFORMATION

591

*Corresponding

592

Telephone: +358 2 215 4760. E-mail: [email protected]

593

ORCID

594

Meheretu Jaleta Dirbeba: https://orcid.org/0000-0002-5986-9259

595

Notes

596

The authors declare no competing financial interest.

597

ACKNOWLEDGMENTS

Author

598

The authors are grateful to the Graduate School in Chemical Engineering (GSCE) for making

599

this work possible. The authors also want to thank the Ethiopian Sugar Corporation for providing 38


Page 38 of 46

Page 39 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

600

the vinasse sample used in this work. This work is part of the activities at the Johan Gadolin

601

Process Chemistry Centre, a Centre of Excellence financed by Åbo Akademi University. The

602

authors also thank Luis Bezerra and Nina Bruun for their help in the experimental work.

603

REFERENCES

604 605 606 607 608

(1)

Bridgwater, A. V. Review of Fast Pyrolysis of Biomass and Product Upgrading.

Biomass and Bioenergy 2012, 38, 68–94. (2)

Mohan, D.; Pittman, C. U.; Steele, P. H. Pyrolysis of Wood/Biomass for Bio-Oil: A

Critical Review. Energy and Fuels 2006, 20 (3), 848–889. (3)

Enestam, S.; Björklund, P.; Engblom, N.; Hamaguchi, M.; Rautanen, M.; Wallmo, H.

609

Energy Trends – Recent and Future Fuel Related Challenges. In: The Proceedings of Impacts of

610

Fuel Quality on Power Production and Environment; Snowbird, Utah, USA, 2014.

611 612 613 614 615 616 617 618

(4)

Jahirul, M. I.; Rasul, M. G.; Chowdhury, A. A.; Ashwath, N. Biofuels Production

through Biomass Pyrolysis- A Technological Review. Energies 2012, 5 (12), 4952–5001. (5)

Bridgwater, A. V.; Meier, D.; Radlein, D. An Overview of Fast Pyrolysis of Biomass.

Org. Geochem. 1999, 30 (12), 1479–1493. (6)

Bridgwater, A. V. Renewable Fuels and Chemicals by Thermal Processing of Biomass.

Chem. Eng. J. 2003, 91 (2–3), 87–102. (7)

Maschio, G.; Koufopanos, C.; Lucchesi, A. Pyrolysis, a Promising Route for Biomass

Utilization. Bioresour. Technol. 1992, 42 (3), 219–231. 39


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

619 620 621 622 623 624 625 626 627

(8)

Guizani, C.; Valin, S.; Billaud, J.; Peyrot, M.; Salvador, S. Biomass Fast Pyrolysis in a

Drop Tube Reactor for Bio Oil Production: Experiments and Modeling. Fuel 2017, 207, 71–84. (9)

Cortez, L. A. B.; Pérez, L. E. B. Experiences on Vinasse Disposal. Part III: Combustion

of Vinasse-#6 Fuel Oil Emulsions. Brazilian J. Chem. Eng. 1997, 14 (1), 9–18. (10)

Polack, J. A.; Day, D. F.; Cho, Y. K. Gasohol from Sugarcane-Stillage Disposition;

Louisiana, USA, 1981. (11)

Adams, T. N.; Frederick, W. J.; Grace, T. M.; Hupa, M.; Lisa, K.; Jones, A. K.; Tran, H.

Kraft Recovery Boilers; Adams, T. N., Ed.; TAPPI PRESS, Atlanta, GA, USA, 1997. (12)

Moraes, B. S.; Junqueira, T. L.; Pavanello, L. G.; Cavalett, O.; Mantelatto, P. E.;

628

Bonomi, A.; Zaiat, M. Anaerobic Digestion of Vinasse from Sugarcane Biorefineries in Brazil

629

from Energy, Environmental, and Economic Perspectives: Profit or Expense? Appl. Energy 2014,

630

113, 825–835.

631

(13)

Sydney, E. B.; Larroche, C.; Novak, A. C.; Nouaille, R.; Sarma, S. J.; Brar, S. K.; Letti,

632

L. A. J.; Soccol, V. T.; Soccol, C. R. Economic Process to Produce Biohydrogen and Volatile

633

Fatty Acids by a Mixed Culture Using Vinasse from Sugarcane Ethanol Industry as Nutrient

634

Source. Bioresour. Technol. 2014, 159, 380–386.

635

(14)

Christofoletti, C. A.; Escher, J. P.; Correia, J. E.; Marinho, J. F. U.; Fontanetti, C. S.

636

Sugarcane Vinasse: Environmental Implications of Its Use. Waste Manag. 2013, 33 (12), 2752–

637

2761.

40


Page 40 of 46

Page 41 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

638

Energy & Fuels

(15)

de Oliveira, B. G.; Carvalho, J. L. N.; Cerri, C. E. P.; Cerri, C. C.; Feigl, B. J. Soil

639

Greenhouse Gas Fluxes from Vinasse Application in Brazilian Sugarcane Areas. Geoderma

640

2013, 200–201, 77–84.

641

(16)

Da Silva, D. R.; Crespi, M. S.; Crnkovic, P. C. G. M.; Ribeiro, C. A. Pyrolysis,

642

Combustion and Oxy-Combustion Studies of Sugarcane Industry Wastes and Its Blends. J.

643

Therm. Anal. Calorim. 2015, 121 (1), 309–318.

644

(17)

Cortes-Rodríguez, E. F.; Fukushima, N. A.; Palacios-Bereche, R.; Ensinas, A. V.; Nebra,

645

S. A. Vinasse Concentration and Juice Evaporation System Integrated to the Conventional

646

Ethanol Production Process from Sugarcane – Heat Integration and Impacts in Cogeneration

647

System. Renew. Energy 2018, 115, 474–488.

648

(18)

Pina, E. A.; Palacios-Bereche, R.; Chavez-Rodriguez, M. F.; Ensinas, A. V.; Modesto,

649

M.; Nebra, S. A. Reduction of Process Steam Demand and Water-Usage through Heat Integration

650

in Sugar and Ethanol Production from Sugarcane – Evaluation of Different Plant Configurations.

651

Energy 2017, 138, 1263–1280.

652 653 654

(19)

Oasmaa, A.; Solantausta, Y.; Arpiainen, V.; Kuoppala, E.; Sipilä, K. Fast Pyrolysis Bio-

Oils from Wood and Agricultural Residues. Energy and Fuels 2010, 24 (2), 1380–1388. (20)

Pellegrini, L. F.; de Oliveira Junior, S. Combined Production of Sugar, Ethanol and

655

Electricity: Thermoeconomic and Environmental Analysis and Optimization. Energy 2011, 36

656

(6), 3704–3715.

41


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

657 658 659

(21)

Larsson, E.; Tengberg, T. Evaporation of Vinasse - Pilot Plant Investigation and

Preliminary Process Design, Chalmers University of Technology, Göteborg, Sweden, 2014. (22)

Dirbeba, M. J.; Brink, A.; DeMartini, N.; Lindberg, D.; Hupa, M. Sugarcane Vinasse

660

CO2 Gasification and Release of Ash-Forming Matters in CO2 and N2 Atmospheres. Bioresour.

661

Technol. 2016, 218, 606–614.

662

(23)

Dirbeba, M. J.; Brink, A.; DeMartini, N.; Zevenhoven, M.; Hupa, M. Potential for

663

Thermochemical Conversion of Biomass Residues from the Integrated Sugar-Ethanol Process —

664

Fate of Ash and Ash-Forming Elements. Bioresour. Technol. 2017, 234, 188–197.

665

(24)

Pereira, S.; Martins, P. C. R.; Costa, M. Kinetics of Poplar Short Rotation Coppice

666

Obtained from Thermogravimetric and Drop Tube Furnace Experiments. Energy and Fuels 2016,

667

30 (8), 6525–6536.

668 669 670 671 672

(25)

Demirbas, A. Pyrolysis of Ground Beech Wood in Irregular Heating Rate Conditions. J.

Anal. Appl. Pyrolysis 2005, 73 (1), 39–43. (26)

Karlström, O.; Brink, A.; Hupa, M. Time Dependent Production of NO from

Combustion of Large Biomass Char Particles. Fuel 2013, 103, 524–532. (27)

Giuntoli, J.; De Jong, W.; Verkooijen, A. H. M.; Piotrowska, P.; Zevenhoven, M.; Hupa,

673

M. Combustion Characteristics of Biomass Residues and Biowastes: Fate of Fuel Nitrogen.

674

Energy and Fuels 2010, 24 (10), 5309–5319.

675 676

(28)

Bhattacharya, P. K.; Parthiban, V.; Kunzru, D. Pyrolysis of Black Liquor Solids. Ind.

Eng. Chem. Process Des. Dev. 1986, 25, 420–426. 42


Page 42 of 46

Page 43 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

677

Energy & Fuels

(29)

Aho, A.; DeMartini, N.; Pranovich, A.; Krogell, J.; Kumar, N.; Eränen, K.; Holmbom,

678

B.; Salmi, T.; Hupa, M.; Murzin, D. Y. Pyrolysis of Pine and Gasification of Pine Chars -

679

Influence of Organically Bound Metals. Bioresour. Technol. 2013, 128, 22–29.

680 681 682

(30)

Decloux, M.; Bories, A. Stillage Treatment in the French Alcohol Fermentation

Industry. Int. Sugar J. 2002, 104 (1247), 509–517. (31)

Dowd, M. K.; Johansen, S. L.; Cantarella, L.; Reilly, P. J. Low Molecular Weight

683

Organic Composition of Ethanol Stillage from Sugarcane Molasses, Citrus Waste, and Sweet

684

Whey. J. Agric. Food Chem. 1994, 42 (2), 283–288.

685

(32)

Parnaudeau, V.; Condom, N.; Oliver, R.; Cazevieille, P.; Recous, S. Vinasse Organic

686

Matter Quality and Mineralization Potential, as Influenced by Raw Material, Fermentation and

687

Concentration Processes. Bioresour. Technol. 2008, 99 (6), 1553–1562.

688

(33)

España-Gamboa, E.; Mijangos-Cortes, J.; Barahona-Perez, L.; Dominguez-Maldonado,

689

J.; Hernández-Zarate, G.; Alzate-Gaviria, L. Vinasses: Characterization and Treatments. Waste

690

Manag. Res. 2011, 29 (12), 1235–1250.

691

(34)

Garcia-Perez, M.; Wang, X. S.; Shen, J.; Rhodes, M. J.; Tian, F.; Lee, W. J.; Wu, H.; Li,

692

C. Z. Fast Pyrolysis of Oil Mallee Woody Biomass: Effect of Temperature on the Yield and

693

Quality of Pyrolysis Products. Ind. Eng. Chem. Res. 2008, 47 (6), 1846–1854.

694 695

(35)

Horne, P. A.; Williams, P. T. Influence of Temperature on the Products from the Flash

Pyrolysis of Biomass. Fuel 1996, 75 (9), 1051–1059.

43


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

696

(36)

Westerhof, R. J. M.; Brilman, D. W. F.; Van Swaaij, W. P. M.; Kersten, S. R. A. Effect

697

of Temperature in Fluidized Bed Fast Pyrolysis of Biomass: Oil Quality Assessment in Test

698

Units. Ind. Eng. Chem. Res. 2010, 49 (3), 1160–1168.

699

(37)

Tsai, W. T.; Lee, M. K.; Chang, Y. M. Fast Pyrolysis of Rice Straw, Sugarcane Bagasse

700

and Coconut Shell in an Induction-Heating Reactor. J. Anal. Appl. Pyrolysis 2006, 76 (1–2), 230–

701

237.

702 703 704 705 706 707 708 709 710

(38)

Yang, S. I.; Wu, M. S.; Wu, C. Y. Application of Biomass Fast Pyrolysis Part I:

Pyrolysis Characteristics and Products. Energy 2014, 66, 162–171. (39)

Pattiya, A.; Suttibak, S. Fast Pyrolysis of Sugarcane Residues in a Fluidised Bed Reactor

with a Hot Vapour Filter. J. Energy Inst. 2017, 90 (1), 110–119. (40)

Pattiya, A.; Sukkasi, S.; Goodwin, V. Fast Pyrolysis of Sugarcane and Cassava Residues

in a Free-Fall Reactor. Energy 2012, 44 (1), 1067–1077. (41)

Toft, A. J. A Comparison of Integrated Biomass to Electricity Systems, Aston

University, Birmingham, UK, 1996. (42)

Fahmi, R.; Bridgwater, A. V.; Donnison, I.; Yates, N.; Jones, J. M. The Effect of Lignin

711

and Inorganic Species in Biomass on Pyrolysis Oil Yields, Quality and Stability. Fuel 2008, 87

712

(7), 1230–1240.

713 714

(43)

Coulson, M. Pyrolysis of Perennial Grasses from Southern Europe. PyNe Newsletter.

2006, pp 6–7.

44


Page 44 of 46

Page 45 of 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

715

Energy & Fuels

(44)

Serikawa, R. M.; Funazukuri, T.; Wakao, N. Effects of Acid and Alkali Added in High-

716

Pressure Oil Conversion of Sugar-Cane Vinasse. Kagaku Kogaku Ronbunshu 1993, 19 (3), 544–

717

548.

718 719 720 721 722 723 724

(45)

Fageria, N. K.; Gheyi, H. R.; Moreira, A. Nutrient Bioavailability in Salt Affected Soils.

J. Plant Nutr. 2011, 34 (7), 945–962. (46)

Matovic, D. Biochar as a Viable Carbon Sequestration Option: Global and Canadian

Perspective. Energy 2011, 36 (4), 2011–2016. (47)

Sadeghi, S. H.; Hazbavi, Z.; Harchegani, M. K. Controllability of Runoff and Soil Loss

from Small Plots Treated by Vinasse-Produced Biochar. Sci. Total Environ. 2016, 541, 483–490. (48)

Houben, D.; Evrard, L.; Sonnet, P. Beneficial Effects of Biochar Application to

725

Contaminated Soils on the Bioavailability of Cd, Pb and Zn and the Biomass Production of

726

Rapeseed (Brassica Napus L.). Biomass and Bioenergy 2013, 57, 196–204.

727

(49)

Baxter, L. L.; Miles, T. R.; Miles Jr., T. R.; Jenkins, B. M.; Milne, T.; Dayton, D.;

728

Bryers, R. W.; Oden, L. L. The Behavior of Inorganic Material in Biomass-Fired Power Boilers:

729

Field and Laboratory Experiences. Fuel Process. Technol. 1998, 54 (1–3), 47–78.

730

(50)

Oasmaa, A.; Meier, D. Analysis, Characterization and Test Methods of Fast Pyrolysis

731

Liquids. In: Fast pyrolysis of biomass: a handbook, vol. 2.; Bridgwater, A. V., Ed.; CPL Press:

732

Newbury, United Kingdom, 2002; pp 23–35.

733 734

(51)

Czernik, S.; Bridgwater, A. V. Overview of Applications of Biomass Fast Pyrolysis Oil.

Energy and Fuels 2004, 18 (2), 590–598. 45


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

735 736 737 738

(52)

Channiwala, S. A.; Parikh, P. P. A Unified Correlation for Estimating HHV of Solid,

Liquid and Gaseous Fuels. Fuel 2002, 81, 1051–1063. (53)

Oasmaa, A.; Czernik, S. Fuel Oil Quality of Biomass Pyrolysis Oils - State of the Art for

the End Users. Energy and Fuels 1999, 13 (4), 914–921.

46


Page 46 of 46

Fast Pyrolysis of Dried Sugar Cane Vinasse at 400 and 500 Â°C

Recommend Documents