Prediction of Synergic Effects of H2O, SO2, and HCl on Mercury and

Sep 14, 2016 - Since there were limited reports concerned with the synergic effects of H2O, SO2, and HCl on mercury and arsenic speciation under oxy-f...
0 downloads 0 Views 1MB Size
Download PDF
Article pubs.acs.org/EF

Prediction of Synergic Effects of H2O, SO2, and HCl on Mercury and Arsenic Transformation under Oxy-Fuel Combustion Conditions Hui Wang, Yufeng Duan,* Ya-ning Li, Yuan Xue, and Meng Liu Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China S Supporting Information *

ABSTRACT: Since there were limited reports concerned with the synergic effects of H2O, SO2, and HCl on mercury and arsenic speciation under oxy-fuel combustion, this paper utilized the results of the thermodynamic equilibrium calculation with FactSage 5.2 to predict the speciation of mercury and arsenic under oxy-coal combustion. Results showed that the percentages of HgCl2 and HgS were higher under oxy-coal combustion atmosphere than those under air-coal combustion atmosphere within the entire range of temperature. It also indicated that H2O(g) inhibited the generation of HgCl2 and HgS and that the mole percentage of HgCl2 was increased by 1 or 2 orders of magnitude, with the concentration of HCl increased by 5 times or 10 times under oxy-coal atmosphere. Arsenic, As2, and AsN are three dominant arsenic species from 900 to 1400 °C under both air- and oxy-coal combustion atmosphere. Besides, the effects of H2O(g) on arsenic distribution was related to the H2O(g) concentration in the flue gas. These results are important for mercury and arsenic control during the oxy-fuel combustion process. fluidized bed. Bithi Roy et al.19 predicted the Cr, arsenic, Se, and Hg transformation under oxy-fuel combustion from 800 to 1400 °C using Victorian brown coal. They found that the concentration of CrO2(OH)2(g) was higher under oxy-coal atmosphere than that under air-coal atmosphere. However, their results did not combine with the experimental data from the oxy-coal circulating fluidized bed. Under air atmosphere, reports about the synergic effects of H2O, SO2, and HCl on mercury and arsenic transformation via thermodynamic equilibrium calculation are plentiful,1,9,18 while under oxy atmosphere, there are few reports about it. This paper utilized the results of the thermodynamic equilibrium calculation to predict the synergic effects of H2O, SO2, and HCl on mercury and arsenic speciation under oxycoal combustion. All results reported during oxy-coal combustion were also compared to those during air-coal combustion. Moreover, the correlative experimental results have been published.20

1. INTRODUCTION Mercury and arsenic have adverse effects on the safety of oxyfuel combustion due to the fact that the mercury and arsenic can corrode the CO2 exchange and storage tanks.1,2 The speciation of mercury and arsenic depends on many factors such as the temperature, the concentration of HCl and SO2 in the flue gas, and so on. Different forms of mercury and arsenic have different properties in the system. For example, there are three mercury species:3 elemental mercury (Hg0), oxidized mercury (Hg2+), and particulate mercury (Hgp). It is difficult to remove elemental mercury due to its insolubility in water and high volatility,4,5 while oxidized mercury and particulate-bound mercury are relatively easy to control with the existing pollution control equipment. Many reports about mercury or arsenic transformation under air-coal combustion are studied.6−8 By the way, there are also some studies about mercury or arsenic under oxy-fuel combustion.1,9−14 Compared to the experimental study, some results can be explored easily by thermodynamic equilibrium calculation. Besides, the thermodynamic equilibrium calculation can help to predict the results such as the possible fates of mercury and arsenic. Fuente-Cuesta et al.15 used kinetic models to predict the adsorption mechanism of mercury. They found that the Yoon− Nelson model provided a suitable fitting for the low mercury absorbed sample. Xu et al.16 used Gaussian 98 to calculate the kinetic data of reactions to simulate the mercury speciation with a specific chemical kinetic. Ling et al.17 summarized a review of the mercury control mechanisms using computational chemistry. However, none of the above predicted mercury species under oxy-coal combustion atmosphere. It is essential to know the mercury and arsenic speciation for enhancing the safety of the CO2 storage system from the oxyfuel circulating fluidized bed since there are few reports1,9,18 about mercury and arsenic speciation in an oxy-coal circulating © 2016 American Chemical Society

2. COMPUTATIONAL DATA AND PROCEDURE The thermodynamic equilibrium calculation software FactSage 5.2 was used to predict the mercury and arsenic distribution under the simulated atmosphere. Chinese bituminous coal was used in this thermodynamic equilibrium calculation, and the selected trace elements in the study were Hg and arsenic. Mercury and arsenic were determined by DMA 80 and ICP-MS, respectively. Information on the coal needed in the thermodynamic equilibrium calculation is shown in Table 1. The ultimate and proximate analyses of coal are shown in Table S1, and the Cl content of the coal is 185 μg/g. This paper designed two kinds of baseline atmospheres (air-coal combustion and oxy-coal combustion atmosphere) combined with our Received: May 8, 2016 Revised: September 11, 2016 Published: September 14, 2016 8463

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468

Article

Energy & Fuels Table 1. Composition of Bituminous Coal Used for Thermodynamic Equilibrium Calculation ultimate analysis (wt %) Car

Har

64.09

3.80

Oar

Nar

9.81

trace elements (mg/kg) Sar

0.75

0.49

Aar

Mar

Hg

16.18 3.76 minerals and inorganic (wt %)

5.689 × 10

−02

As

Cd

Cr

2.8

0.08

21.7

Na2O

MgO

Al2O3

SiO2

K2O

CaO

Fe2O3

TiO2

SO3

P2O5

2.43

4.62

19.51

36.86

0.35

19.89

10.17

1.07

3.05

1.03

Table 2. Coal Combustion Atmosphere Used for Thermodynamic Equilibrium Calculation atmosphere

O2 (vol %)

CO2 (vol %)

air combustion oxy-coal combustion (1)-H2O (2)-H2O (3)-H2O (4)-H2O (1)-HCl (2)-HCl (3)-HCl (4)-HCl (5)-HCl (6)-HCl (1)-SO2 (2)-SO2 (3)-SO2 (4)-SO2 (5)-SO2 (6)-SO2

3.48 13.63

13.94 64.26

75.38 4.57

13.63

64.26

balance

13.63

13.63

64.26

64.26

N2 (vol %)

balance

balance

H2O (vol %)

HCl (ppm)

SO2 (ppm)

NO (ppm)

7.1 17.4 0 13.92 17.4 20.88

50 50

238 615

236 319.2

50

615

319.2

0 40 50 60 250 500

615

319.2

50

0 492 615 738 3075 6150

319.2

17.4

17.4

previous results from 6 kWth21,22and 50 kWth.23 Figure S1 shows the schematic diagram of 50 kWth oxy-CFB with warm flue gas recycling designed by our group from Southeast University.23 Information of different calculation conditions was listed in Table 2. All calculations used 8 kg/h dry coal at the atmospheric pressure with temperature varying from 700 to 1400 °C. The volumetric flows of the flue gas under air-coal combustion and oxy-coal combustion were set as 60.74 and 56 m3/h, respectively. Thermodynamic equilibrium calculation for Hg and arsenic during different combustion conditions are listed in Table 2. There were many products from the calculation results, but only the major mercury and arsenic species in thermodynamic equilibrium calculation are displayed and discussed in this paper. The process of thermodynamic equilibrium calculation was illustrated in Figure S2. All results of thermodynamic equilibrium calculations were obtained using an air/gas mixture, which was consistent with the experimental conditions. However, it should be known that the kinetics were not considered, so the results may not conform to the chemical equilibrium though they reached the thermal equilibrium. All cases in the thermodynamic calculation were assumed to reach both thermal and chemical equilibrium conditions.

3. RESULTS AND DISCUSSION 3.1. Mercury and Arsenic Release under Air- and OxyCoal Combustion Atmosphere. Compared to air-coal combustion atmosphere, the higher concentrations of O2, CO2, H2O, SO2, and NO in oxy-coal combustion atmosphere may affect the speciation and distribution of mercury and arsenic species. Thermodynamic equilibrium calculation can help to compare the distributions of mercury and arsenic between air- and oxy-coal combustion atmosphere. 3.1.1. Mercury Release. From Figure 1a, it can be shown that Hg (× 10−8 mol) is the dominant mercury species at temperatures from 700 to 1400 °C. HgO is predicted to

Figure 1. Equilibrium composition of major Hg species under air- and oxy-coal combustion atmosphere: (a) composition of Hg and HgO; (b) composition of HgCl2 and HgS. 8464

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468

Article

Energy & Fuels increase from 0 to 250 × 10−13 mol with the increase of temperature (beyond 1100 °C) under oxy-coal combustion atmosphere, which is in line with the observations by Font,1 who found that the elemental Hg was also the dominant species (82%) in the flue gas in the 90 kWth bubbling fluidized bed. Besides, results from Roy et al.19 also concluded that elemental mercury accounted for more than 98.5% in the gaseous mercury. Figure 1b indicates that HgCl2 (× 10−22 mol) is greater under oxy-coal combustion atmosphere than that under air-coal combustion atmosphere within the entire range of temperature and that HgCl2 increases with the increase of temperature. For HgS (10−14 mol), HgS under air-coal combustion atmosphere increases with the increase of temperature. However, under oxy-combustion atmosphere, HgS increases with temperature first and reaches a maximum at about 1050 °C, then begins to decrease. Besides, HgS is higher in oxy-coal combustion atmosphere than in air-coal combustion atmosphere when the temperature is lower than 1200 °C. When temperature exceeds 1300 °C, HgS is greater under air-coal combustion atmosphere than under oxy-combustion atmosphere. The relatively high amount of HgCl2 and HgS under oxy-coal atmosphere is due to the higher water vapor, in line with results from Wu et al.24 and Roy et al.19 3.1.2. Arsenic Release. As seen from Figure 2, at temperatures from 700 to 800 °C, As2 and AsN are two

could be inferred that arsenic would result from the increasing rate of decomposition of As2 as temperature increases. The increment of the AsN mole percentage is due to the fact that the rate of reaction 125 increases with the increase of temperature. As + ·N3 → N2 + AsN A = 2.09 × 10−11 cm 3·mol−1· s−1 k = 2.09 × 10−11 cm 3·mol−1· s−1

(1)

3.2. Effects of Water Vapor on Mercury and Arsenic Release under Oxy-Coal Combustion Atmosphere. 3.2.1. Mercury Release. Figure 3a shows that H2O(g) has

Figure 2. Equilibrium distribution of major As species under air- and oxy-coal combustion atmosphere. Figure 3. Equilibrium composition of major Hg at different water vapor concentrations under oxy-coal combustion atmosphere: (a) composition of Hg and HgO; (b) composition of HgCl2 and HgS.

dominant arsenic species under both air and oxy atmospheres. When the temperature varies from 900 to 1400 °C, arsenic, As2, and AsN are the three major arsenic species. Within the overall temperature range, the percentage of arsenic and As2 under oxy-coal combustion atmosphere is greater than that under aircoal combustion atmosphere, while the percentage of AsN is lower under oxy-coal combustion atmosphere than that under air-coal combustion atmosphere due to the lower nitrogen under oxy-coal combustion atmosphere. As temperature increases from 700 to 1400 °C under air-coal combustion atmosphere, the percentage of arsenic and AsN increases from 0.022 to 19.39% and from 29.04 to 80.14% with slight fluctuation at 1300 °C, respectively, and the percentage of As2 decreases from 70.94 to 0.43%. For the same temperature range under oxy-coal combustion atmosphere, the percentage of arsenic and AsN increases from 0.026 to 47.02% and from 8.89 to 50.06% with slight fluctuation at 1300 °C, respectively, and the percentage of As2 decreases from 91.07 to 2.9%. It

little impact on the composition of Hg and HgO. Figure 3b indicates that H2O(g) is the inhibitor of HgCl2 and HgS. The elimination of Cl and S occurs via reactions 226 and 3,27 that is, HgCl2 and HgS decrease with the increase of H2O(g). H 2O + NO + Cl → HOCl + HNO ·

OH + HSO2 → SO2 + H 2O

(2) (3)

3.2.2. Arsenic Release. Figure 4 shows the effects of water vapor on arsenic species under oxy-coal combustion atmosphere. It can be seen that arsenic, As2, and AsN respectively remain the same, decrease, and increase with H2O(g) increasing to 20.88 vol %, respectively, which indicates that the effects of H2O(g) on arsenic distribution are related to the concentration of H2O(g) in the flue gas. 8465

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468

Article

Energy & Fuels

The mechanism for the above phenomena is analyzed below. The mole percentage of HgCl2 increases due to the fact that the rate of reaction 425 increases with the increase of HCl; that the mole percentage of HgS increases first is due to the fact that reaction 5 shifts to the right side and more HgS is generated when SO2 concentration increases. That the mole percentage of HgS decreases is due to the fact that the elimination of HgS and HCl occurs via reaction 6. HgO + 2HCl → HgCl2 + H 2O

(4)

Hg + SO2 → HgS + O2

(5)

HgS + 2HCl → HgCl2 + H 2S

(6)

3.3.2. Arsenic Release. Figure 6 shows the effects of hydrogen chloride on arsenic species under oxy-coal

Figure 4. Equilibrium distribution of major As at different water vapor concentrations under oxy-coal combustion atmosphere. (Balance of 100% on the vertical axis is the other As-species: As4O6, AsS, and AsCl3).

3.3. Effect of Hydrogen Chloride on Mercury and Arsenic Release under Oxy-Coal Combustion Atmosphere. 3.3.1. Mercury Release. From Figure 5a,b, it can be

Figure 6. Equilibrium distribution of major As at different hydrogen chloride concentrations under oxy-coal combustion atmosphere. (Balance of 100% on the vertical axis is the other As-species: As4O6, AsS, and AsCl3).

combustion atmosphere. It can be seen that HCl has little impact on the mole percentage of arsenic, As2, and AsN. 3.4. Effects of Sulfur Dioxide on Mercury and Arsenic Release under Oxy-Coal Combustion Atmosphere. 3.4.1. Mercury Release. From Figure 7a,b, it can be found that SO2 has little impact on the mole percentage of Hg, HgO and HgCl2. Besides, SO2 accelerates the mole percentage of HgS, as shown in Figure 5b, which is due to the fact that reaction 5 shifts to the right side and more HgS is generated when SO2 concentration increases. 3.4.2. Arsenic Release. Figure 8 shows the effects of SO2 on arsenic species under oxy-coal combustion atmosphere, and it can be seen that SO2 has little impact on the mole percentage of arsenic, As2 and AsN.

4. CONCLUSIONS Thermodynamic equilibrium calculation about the synergic effects of H2O, SO2, and HCl on mercury and arsenic under different combustion conditions in oxy atmosphere and over a broad range of temperatures (700−1400 °C) is studied; some important conclusions can be drawn as follows: HgCl2 is greater under oxy-coal combustion atmosphere than under air-coal combustion atmosphere within the entire range of temperature. HgS increases with the increase of temperature under air-coal combustion atmosphere. From 900 to 1400 °C, arsenic, As2, and AsN are three major arsenic species under both air- and oxy-coal combustion atmosphere.

Figure 5. Equilibrium composition of major Hg at different hydrogen chloride concentrations under oxy-coal combustion atmosphere: (a) composition of Hg and HgO; (b) composition of HgCl2 and HgS.

seen that HCl has no effect on Hg or HgO. As shown in Figure 5b, HgCl2 increases with the increase of HCl; HgS increases with the increase of HCl when temperature is below 1100 °C. When temperature exceeds 1100 °C, HgS decreases with the increase of HCl. Besides, when the concentration of HCl is increased by 5 or 10 times, the mole percentage of HgCl2 is increased by 1 or 2 orders of magnitude. 8466

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468

Article

Energy & Fuels

concentration of SO2 accelerates the mole percentage of HgS during oxy-coal combustion.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.energyfuels.6b01109. Schematic diagram of warm recycle oxy-coal atmosphere in circulating fluidized bed. Schematic diagram of the process of thermodynamic equilibrium calculation. Ultimate and proximate analyses of bituminous coal. (PDF)

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Tel./Fax: +86 025-83795652. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (51376046, 51576044); the National Key Research and Development Program (2016YFC0201105, 2016YFB0600604-02, 2016YFB0600203-03); the Fundamental Research Funds for the Central Universities, Graduate Student Research and Innovation Program of Jiangsu Province (CXZZ13_0093, KYLX_0115, KYLX_0184, KYLX15_0071); and the Scientific Research Foundation of Graduate School of Southeast University (YBJJ1505). The software FactSage 5.2 was supported by Institute for thermal power engineering of Zhejiang University.

Figure 7. Equilibrium composition of major Hg at different sulfur dioxide concentrations under oxy-coal combustion atmosphere: (a) composition of Hg and HgO; (b) composition of HgCl2 and HgS.

■

REFERENCES

(1) Font, O.; Córdoba, P.; Leiva, C.; Romeo, L.; Bolea, I.; Guedea, I.; Moreno, N.; Querol, X.; Fernandez, C.; Díez, L. Fate and abatement of mercury and other trace elements in a coal fluidised bed oxy combustion pilot plant. Fuel 2012, 95, 272−281. (2) Spörl, R.; Belo, L.; Shah, K.; Stanger, R.; Giniyatullin, R.; Maier, J. r.; Wall, T.; Scheffknecht, G. n. Mercury emissions and removal by ash in coal-fired oxy-fuel combustion. Energy Fuels 2014, 28 (1), 123−135. (3) Senior, C. L.; Sarofim, A. F.; Zeng, T.; Helble, J. J.; Mamani-Paco, R. Gas-phase transformations of mercury in coal-fired power plants. Fuel Process. Technol. 2000, 63 (2), 197−213. (4) Yang, H.; Xu, Z.; Fan, M.; Bland, A. E.; Judkins, R. R. Adsorbents for capturing mercury in coal-fired boiler flue gas. J. Hazard. Mater. 2007, 146 (1), 1−11. (5) Tian, H.; Wang, Y.; Xue, Z.; Qu, Y.; Chai, F.; Hao, J. Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007. Sci. Total Environ. 2011, 409 (16), 3078−3081. (6) Senior, C. Mercury Behavior in Coal Combustion Systems. Mercury Control: for Coal-Derived Gas Streams 2014, 109−132. (7) Li, Z.; Duan, Y.; Wang, Y.; Huang, Z.; Meng, S.; Shen, J. Mercury removal by ESP and WFGD in a 300 MW coal-fired power plant. J. Fuel Chem. Technol. (Beijing, China) 2013, 41 (4), 491−498. (8) WANG, Y.; WEI, J.; DUAN, Y. Research of the Existing Air Pollutant Control Devices on Mercury Speciation and Removal in Coal-fired Power Plants. Boiler Technology 2013, No. 3, 017. (9) Roy, B.; Chen, L.; Bhattacharya, S. Nitrogen Oxides, Sulfur Trioxide, and Mercury Emissions during Oxy-fuel Fluidized Bed Combustion of Victorian Brown Coal. Environ. Sci. Technol. 2014, 48 (24), 14844−14850.

Figure 8. Equilibrium distribution of major As at different sulfur dioxide concentrations under oxy-coal combustion atmosphere. (Balance of 100% on the vertical axis is the other As-species: As4O6, AsS, and AsCl3).

H2O(g) inhibits the generation of HgCl2 and HgS. Moreover, the effects of H2O(g) on the arsenic distribution is related to H2O(g) concentration in the flue gas. When the concentration of HCl is increased by 5 or 10 times, the mole percentage of HgCl2 is increased by 1 or 2 orders of magnitude. The relatively high amount of HgCl2 and HgS under oxy-coal atmosphere is due to the higher water vapor concentration. The predicted results indicate that SO2 and NO have little impact on mercury and arsenic species but that the 8467

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468

Article

Energy & Fuels (10) Roy, B.; Bhattacharya, S. Oxy-fuel fluidized bed combustion using Victorian brown coal: An experimental investigation. Fuel Process. Technol. 2014, 117, 23−29. (11) Yang, J.; Zhao, Y.; Chang, L.; Zhang, J.; Zheng, C. Mercury adsorption and oxidation over cobalt oxide loaded magnetospheres catalyst from fly ash in oxyfuel combustion flue gas. Environ. Sci. Technol. 2015, 49 (13), 8210−8218. (12) Lopez-Anton, M. A.; Rumayor, M.; Díaz-Somoano, M.; Martínez-Tarazona, M. R. Influence of a CO2-enriched flue gas on mercury capture by activated carbons. Chem. Eng. J. 2015, 262, 1237− 1243. (13) Fernández-Miranda, N.; Lopez-Anton, M. A.; Díaz-Somoano, M.; Martínez-Tarazona, M. R. Mercury oxidation in catalysts used for selective reduction of NOx (SCR) in oxy-fuel combustion. Chem. Eng. J. 2016, 285, 77−82. (14) Fernández-Miranda, N.; Rumayor, M.; Lopez-Anton, M. A.; Díaz-Somoano, M.; Martínez-Tarazona, M. R. Mercury Retention by fly ashes from oxy-fuel processes. Energy Fuels 2015, 29 (4), 2227− 2233. (15) Fuente-Cuesta, A.; Diamantopoulou, I.; Lopez-Anton, M.; DiazSomoano, M.; Martínez-Tarazona, M.; Sakellaropoulos, G. Study of Mercury Adsorption by Low-Cost Sorbents Using Kinetic Modeling. Ind. Eng. Chem. Res. 2015, 54, 5572. (16) Xu, M.; Qiao, Y.; Zheng, C.; Li, L.; Liu, J. Modeling of homogeneous mercury speciation using detailed chemical kinetics. Combust. Flame 2003, 132 (1), 208−218. (17) Ling, L.; Fan, M.; Wang, B.; Zhang, R. Application of computational chemistry in understanding the mechanisms of mercury removal technologies: a review. Energy Environ. Sci. 2015, 8 (11), 3109−3133. (18) Wu, H.; Liu, H.; Wang, Q. H.; Luo, G. Q.; Yao, H.; Qiu, J. R. Experimental study of homogeneous mercury oxidation under O2/ CO2 atmosphere. Proc. Combust. Inst. 2013, 34, 2847−2854. (19) Roy, B.; Choo, W. L.; Bhattacharya, S. Prediction of distribution of trace elements under oxy-fuel combustion condition using Victorian brown coals. Fuel 2013, 114, 135−142. (20) Wang, H.; Duan, Y.; Li, Y.; Xue, Y.; Liu, M. Investigation of mercury emission and its speciation from an oxy-fuel circulating fluidized bed combustor with recycled warm flue gas. Chem. Eng. J. 2016, 300, 230−235. (21) Wang, H.; Duan, Y.; Li, Y.; Liu, M. Experimental Study on Mercury Oxidation in a Fluidized Bed under O2/CO2 and O2/N2 Atmospheres. Energy Fuels 2016, 30, 5065. (22) Wang, H.; Duan, Y.; Li, Y.; Xue, Y.; Liu, M. Inner Relationship between CO, NO, and Hg in a 6 kWth Circulating Fluidized Bed Combustor under an O2/CO2 Atmosphere. Energy Fuels 2016, 30 (5), 4221−4228. (23) Duan, L.; Sun, H.; Zhao, C.; Zhou, W.; Chen, X. Coal combustion characteristics on an oxy-fuel circulating fluidized bed combustor with warm flue gas recycle. Fuel 2014, 127, 47−51. (24) Wu, H.; Liu, H.; Wang, Q.; Luo, G.; Yao, H.; Qiu, J. Experimental study of homogeneous mercury oxidation under O2/ CO2 atmosphere. Proc. Combust. Inst. 2013, 34 (2), 2847−2854. (25) Henshaw, T.; McElwee, D.; Stedman, D.; Coombe, R. Chemiluminescent reaction of arsenic (4Su) atoms with azide radicals. J. Phys. Chem. 1988, 92 (16), 4606−4610. (26) Xu, Z.; Lin, M. Computational Studies on Metathetical and Redox Processes of HOCl in Gas Phase. III. Its Self-Reaction and Interactions with HNOx (x= 1−3). J. Phys. Chem. A 2010, 114 (16), 5320−5326. (27) Durie, R.; Johnson, G.; Smith, M. The effect of sulfur dioxide on hydrogen-atom recombination in the burnt gas of premixed fuel-rich propane-oxygen-nitrogen flames. Combust. Flame 1971, 17 (2), 197− 203.

8468

DOI: 10.1021/acs.energyfuels.6b01109 Energy Fuels 2016, 30, 8463−8468