Syngas Purification by Porous Amino ... - ACS Publications

Subscriber access provided by NEW YORK UNIV

Article

Syngas Purification by Porous AminoFunctionalized Titanium Terephthalate MIL-125 Maria João Regufe, Javier Tamajon, Ana Mafalda Ribeiro, Alexandre F. P. Ferreira, U-Hwang Lee, Young Kyu Hwang, Jong-San Chang, Christian Serre, José Miguel Loureiro, and Alirio Egidio Rodrigues Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.5b00975 • Publication Date (Web): 22 Jun 2015 Downloaded from http://pubs.acs.org on June 24, 2015

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 free 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 accessible to all readers and 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.

Energy & Fuels 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 34

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

Syngas Purification by Porous AminoFunctionalized Titanium Terephthalate MIL-125 Maria João Regufe1, Javier Tamajon1, Ana M. Ribeiro1,*, Alexandre Ferreira1, U-Hwang Lee2, Young Kyu Hwang2, Jong-San Chang2,3,*, Christian Serre4, José M. Loureiro1, Alírio E. Rodrigues1

1 LSRE-Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal 2 Catalysis Center for Nanocatalysts, Korea Research Institute of Chemical Technology (KRICT), Jang-dong 100, Yuseong, Daejeon, Korea 3 Department of Chemistry, Sungkyunkwan University, Suwon 440-476, Korea 4 Institut Lavoisier de Versailles, UMR 8180 CNRS, Université de Versailles, 45 Avenue des Etats Unis 78035 Versailles cedex, France

ACS Paragon Plus Environment

1

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 2 of 34

ABSTRACT

The adsorption equilibrium of carbon dioxide (CO2), carbon monoxide (CO), nitrogen (N2), methane (CH4), and hydrogen (H2), was studied at 303 K, 323 K, and 343 K, and pressures up to 7 bar, in titanium based MOF granulates, amino-functionalized titanium terephthalate MIL125(Ti)_NH2. The affinity of the different adsorbates towards the adsorbent presented the following order: CO2 > CH4 > CO > N2 > H2 from the most adsorbed to the less adsorbed component. Subsequently, adsorption kinetics and multicomponent adsorption equilibrium were studied by means of single, binary and ternary breakthrough curves at 323 K and 4.5 bar with different feed mixtures. Both studies are complementary, and aim the syngas purification for two different applications, hydrogen production and H2/CO composition adjustment to be used as feed in the Fisher-Tropsch processes. The isosteric heats were calculated from the adsorption equilibrium isotherms and are 21.9 kJ mol-1 for CO2, 14.6 kJ mol-1 for CH4, 13.4 kJ mol-1 for CO, and 11.7 kJ mol-1 for N2. In the overall pressure and temperature range the adsorption equilibrium isotherms were well regressed against the Langmuir model. The multicomponent breakthrough experimental results allowed validation of the adsorption equilibrium predicted by the multicomponent extension of the Langmuir isotherm, and validation of the fixed-bed mathematical model. To conclude, two pressure swing adsorption cycles were designed and performed experimentally, one for hydrogen purification from a 30%/70% CO2/H2 mixture (hydrogen purity was 100 % with recovery of 23.5 %), and a second PSA cycle to obtain a light product with a H2/CO ratio between 2.2 and 2.4 to feed to a Fischer-Tropsch processes. The experimental cycle produced a light stream with a H2/CO ratio of 2.3, and a CO2 enriched stream with 86.6 % purity as heavy product. The CO2 recovery was 93.5 %


2

Page 3 of 34

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

INTRODUCTION Synthesis gas or syngas is used as raw material for various industrial processes. It is a key intermediate to produce a vast quantity of compounds in the chemical industry. One of the main goals of many research groups involves the exploration of effective ways of purifying syngas either for the production of high purity hydrogen or for tuning its composition (H2+CO). Syngas can be produced from different carbon containing raw materials (natural gas, naphta, biomass, coal, alcohols or oxygenates, liquid residues) and by diverse processes (steam reforming of hydrocarbons, gasification, autothermal reforming, non-catalytic partial oxidation). Depending on its origin, syngas can contain various impurities as carbon dioxide, nitrogen, methane, ethane, ethylene, hydrogen sulfide, ammonia and water.1 Besides being used to obtain high purity H2, syngas can be converted into high value products such as methanol or synthetic fuel via the Fischer-Tropsch (FT) process. In order to be used in these processes, the syngas composition must be adjusted in terms of ideal H2/CO ratios.2 The syngas is therefore treated in order to remove the impurities and/or adjust its composition to the desired values.3, 4 Adsorptive processes, due to their low energy requirements, are the focus of many research works.5-10 Commercial applications for production of high purity hydrogen use PSA processes with layered beds of activated carbons and 5A zeolite.11 The hydrogen purity can reach 99.999% at 70-80% recovery.12 In the case of syngas composition adjustment, amine absorption is the currently used process13 but Pressure Swing Adsorption (PSA) processes have been looked at as a viable alternative.3, 4, 10, 14, 15

Ortiz et al.3 performed an optimization study for a methanol synthesis process from

supercritical water reforming of glycerol in which PSA was considered for syngas conditioning.


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

Page 4 of 34

In another work, Martin et al.4 reported the results of the optimization of a process to produce FT diesel from biomass gasification. The use of a PSA for adjustment of the syngas composition was assessed. In both these studies, the authors looked into the overall process, from carbon source to liquid, with minor detail on the PSA process. Ribeiro et al. 10, 14, 15 presented the design of PSA processes at industrial scale for adjustment of syngas composition for the production of methanol or FT diesel and simultaneous production of a CO2 stream with purity above 95%. The selected adsorbent material was the activated carbon Norit R2030. They concluded that, using the designed PSA process coupled with a series of tanks that collect the blowdown stream at different pressures, the PSA process can compete with the state of the art absorbent based processes. One of the main focuses of the ongoing research is on new adsorbent materials that can improve the processes performance. The past decades have been marked by the emergence of new materials, like molecular sieves, carbon nanotubes, mesoporous silica materials and, more recently, metal-organic frameworks (MOFs).16 MOFs are hybrid solids that are composed by organic and inorganic moieties linked by strong coordination bonds. The moieties can be extended infinitely in one, two or three dimensions.17 Large pore surface area, highly designable framework, pore shape and size and surface functionality are key features of these materials.16 Different studies of gas phase separations with MOFs have been reported in the literature, such as methane/carbon dioxide separation18-20, separation of light olefins and paraffins21-24, separation of xylene and hexane isomers25-28 and hydrogen purification.7, 29-31 In this work, the amino-functionalized titanium terephthalate MIL-125(Ti)_NH2, produced in the form of granulates, was studied for syngas treatment by adsorptive processes (PSA), considering both the objectives of hydrogen purification and composition adjustment for FT


4

Page 5 of 34

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

process. Adsorption equilibrium data of pure gases CO2, CO, N2, CH4 and H2 were measured. Single, binary and ternary adsorption and desorption breakthrough curves were carried out at 323 K and 4.5 bar. A mathematical model was used to predict the breakthrough curves and to design two PSA experimental tests, one for the purification of H2 from a binary mixture (CO2/H2); and one to adjust the syngas composition from a CO2/CO/H2 feed mixture.

EXPERIMENTAL Materials In this study, the MIL-125(Ti)_NH2 adsorbent in granulated form manufactured by the Korea Research Institute of Chemical Technology (KRICT) was used for syngas purification (Figure 1). This material is a titanium(IV) 2-aminoterephthalate, built up from cyclic Ti8O8(OH)4 oxoclusters and 2-aminoterephthalate ligands, with the chemical formula Ti8O8(OH)4-(O2CC6H3NH2-CO2)6 and has a three-dimensional pseudo-cubic structure with highly interconnected pores. It possesses two types of cages corresponding to the octahedral (12.5 Å) and tetrahedral (6 Å) vacancies of a cc packing accessible through triangular narrow windows of ca. 6 Å.32

Figure 1. MIL-125(Ti)_NH2 granulates as manufactured by KRICT. MIL-125(Ti)_NH2 was synthesized at 373 K for 24 h according to the method described elsewhere. 33 The molar ratio of Ti : 2-aminoterephthalic acid : MeOH : DMF was 1 : 1.5 : 24 :


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

Page 6 of 34

50. The MIL-125(Ti)_NH2 granules were prepared by wet granulation of the powder thus obtained. The powder was first mixed with an ethanolic solution of 3 wt% polymer binder mixture containing polyvinyl groups. The mixture of the MOF powder and binder was then shaped by a home-made fan-type granulator. Before the granulation, the powder samples were finely grinded to achieve a fine and similar particle size (< 20 µm). Then, ethanol as the solvent was periodically wetted on the solid mixture to allow the agglomeration of the powder, yielding MIL-125(Ti)_NH2 granules. The MIL-125(Ti)_NH2 granulates were characterized by helium pycnometry, mercury porosimetry and scanning electron micrograph (SEM)/Energy Dispersive X-ray (EDS). The main characteristics of the adsorbent are presented in Table 1. The SEM images and the EDS spectra are presented in Figure S1 (Supporting information). It can be seen that the crystals have an irregular shape but with narrow size distribution. The average crystal size is about 0.6 μm. The EDS spectra presents the expected elements from the MIL-125(Ti)_NH2 composition (C, O, Ti and N). Table 1 - MIL-125(Ti)_NH2 granulates characteristics. Particle radius (mm)

2.00

Crystal radius (μm)

0.6

Solid density (kg m-3)

1450

Apparent particle density (kg m-3)

550

The adsorbate gases used in the experiments were carbon dioxide (99.998%), carbon monoxide (99.997%), methane (99.95%), nitrogen (99.995%) and hydrogen (99.9999%). Helium


6

Page 7 of 34

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

(99.999%) was used as inert gas for adsorbent activation and regeneration. All gases were provided by L’Air Liquide.

Adsorption equilibrium Pure gas adsorption equilibrium isotherms were measured in a magnetic suspension microbalance (Rubotherm, Germany) with a precision of 0.01 mg. The inlet of the balance is connected to a system of valves, three-way and needle, for adsorptive addition. The outlet is connected to a K-type thermocouple to measure the temperature; to two pressure transducers, one that operates between 0 and 350 mbar and the other between 0 and 10 bar; and to a vacuum pump used for sample activation and cell depressurization. The temperature inside the cell is controlled by fluid circulation in a cell jacket. The system control and data acquisition is done by a LabVIEW software. Figure 2 represents the experimental set-up used for the adsorption measurements.

Figure 2. Schematic diagram of the experimental set-up used for the adsorption measurements.. Initially, approximately 2 g of adsorbent was placed in a basket suspended by the permanent magnet of the balance. The adsorbent was activated at 423 K under vacuum. The heating rate to reach this temperature was 1 K/min. In order to correct the buoyancy effect, two helium


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

Page 8 of 34

pycnometries to the system were performed, one with and another without the adsorbent. To obtain one experimental point of the adsorption isotherm, a small amount of gas was added to the cell that contains the adsorbent sample. After reaching the equilibrium, the procedure was repeated to obtain additional points, until the high desired pressure is achieved. Afterwards, the cell was progressively depressurized and desorption points of the isotherm were obtained. In order to calculate the amount adsorbed it is necessary to correct for the buoyancy effect, in particular for high pressures. This was performed according to the following equation34 q=

∆ ( )

(1)

where ∆m is the difference of weight between one measurement and the previous one, VS is the volume of the solid adsorbent, VC is the volume of the permanent magnet, of the sample basket and of the glass wool used to hold the sample, ρG is the density the gas phase at the measuring conditions (T,P), ρL is the density of the adsorbed phase, mS is the adsorbent mass, and Mw is the adsorbate molecular weight. VS, VC and mS are measured by helium pycnometry, assuming that helium is not adsorbed. The adsorption equilibrium isotherms were measured for H2, CO2, CO, CH4 and N2 at 303, 323 and 343 K up to 7 bar. The CO isotherms were measured up to 3 bar. As this value is above the CO partial pressure in the fixed bed tests, this limit was found to be reasonable.

Fixed-bed and PSA Breakthrough curves and PSA experiments were performed in a lab-scale fixed-bed/PSA unit. This unit can work at temperatures between 298 and 423 K and in the pressure range of 0.1-5 bar. The system pressure is controlled via a back-pressure regulator (BPR) from Bronkhorst which works between 0-5 bar. The feed is obtained from individual gas streams, through the


8

Page 9 of 34

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

accurate control of three mass flow controllers from Alicat Scientific. The total flow rate at the outlet of the column is assessed by a flow meter also from Alicat Scientific. The set-up is remotely and automatically controlled by Labview software. The temperature histories of three thermocouples as well as the total flow rate at the outlet of the column were recorded during the experiments. The composition of the outlet stream is analyzed by gas chromatography. A Varian CP-3800 gas chromatograph (GC) was used, coupled with a system of two valves, a two position, 6-port automatic valve and a 16 loop valve to collect the samples. The analyses were done using a Supelco GC packed column under isothermal conditions (483 K) and using a constant inert carrier gas flow rate, which was helium. A thermal conductivity detector (TCD) that operates at 453 K was used. A stainless steel column with 2.11 cm internal diameter was packed with 42.4 g of MIL125(Ti)_NH2 which resulted in a bed with 32.3 cm. The adsorbent was activated in situ under 0.05 SLPM helium flow rate at 423 K overnight. After the activation, the final mass of adsorbent was 40.2 g, which corresponds to 5.2% loss. The three thermocouples are located at 8.1 cm (bottom), 19.1 cm (middle) and 30 cm (top) from the beginning of the bed and are placed approximately at the center of the bed (radially), measuring the gas temperature. The characteristics of the column are given in Table 2. Table 2 - Adsorption bed characteristics. Bed length (m)

0.323

Bed diameter (m)

0.021

Bed porosity

0.35

Mass of adsorbent (kg)

0.0402

Thermocouples position (m)

0.081; 0.191; 0.300


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 34

Single, binary and ternary breakthrough curves were performed and all experiments were carried out at 323 K and 4.5 bar. The conditions under which the breakthrough curves were obtained are summarized in Table 3. Additional experiments are presented in Supporting Information and their corresponding conditions are given in Table S1. At the beginning of each experiment, the column was filled with He or H2 at the feed pressure and temperature. The desired gas mixture was fed to the column until saturation (adsorption). After this, the inlet stream was changed to He or H2 at the same total volumetric flowrate (desorption).

Table 3 - Experimental conditions used in the breakthrough experiments at 323 K and 4.5 bar.

Run

Column initial conditions

Flowrate (SLPM)

Adsorption feed composition (%)

Desorption feed composition (%)

Start time of desorption (s)

BT1

He

0.481

CO2 – 41.6

He – 100

3474

BT2

He

0.470

CO2 – 32.4 H2 - 67.6

He – 100

5304

BT3

H2

0.530

CO2 – 26.6 CO - 23.5 H2 - 49.9

H2 – 100

8504

Two PSA cycles were performed with different objectives. In the first cycle (Run PSA1), hydrogen purification was carried out at 323 K from a mixture containing 30% CO2 and 70% H2. Run PSA1 starts with co-current pressurization with feed mixture up to a high pressure (PHIGH) of 4.0 bar. After the high pressure is reached, the back pressure regulator opens and a feed step starts. In this step, a H2 stream is obtained at the product end. Afterwards, a blowdown step is carried out where the pressure bed is decreased to a low pressure (PLOW) of 1.0 bar countercurrently. The last step is purge, also done countercurrently, in which a stream of pure H2 is fed to the column. This PSA scheme is illustrated in Figure 3.


10

Page 11 of 34

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

Figure 3. Cycle sequence used in the PSA for hydrogen purification (Run PSA1). In the second cycle (Run PSA2), performed also at 323 K, a mixture with 30% CO2, 22% CO and 48% H2 was fed to the PSA process in order to obtain two products: a CO2 enriched stream (heavy product) and a H2+CO product with a H2/CO stoichiometric ratio of approximately 2.3, suitable as feed for Fischer-Tropsch process (light product). As in the previous run, this cycle starts with co-current pressurization and feed steps with feed mixture at PHIGH of 4.0 bar. Then a rinse step with a pure CO2 stream is carried out in order to increase the CO2 content in the bed. The enriched stream with H2 and CO is obtained during the feed and rinse steps. Again, in the blowdown step, the pressure is decreased to PLOW (1.0 bar) countercurrently. A purge step is carried out with a mixture containing 32% CO and 68% H2. These last two steps produce a CO2 enriched stream. The Run PSA2 cycle scheme is presented in Figure 4.


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

Page 12 of 34

Figure 4. Cycle sequence used in the PSA for syngas composition adjustment (Run PSA2).

Table 4 - Experimental conditions used in the PSA experiments performed at 323 K. Run

Pressurization Duration (s)

PSA1

PSA2

Pressure (bar)

Feed

310 1.0 to 4.0

4.0

Rinse

Blowdown

Purge

-

79

123

-

4.0 to 1.0

1.0

Flow rate (SLPM)

0.50

-

-

0.50

Duration (s)

332

221

94

92

4.0

4.0 to 1.0

1.0

0.50

-

0.30

Pressure (bar) Flow rate (SLPM)

1.0 to 4.0 0.43

4.0

The PSA runs experimental conditions are presented in Table 4. At the beginning of each PSA experiment, the column was filled with hydrogen at high pressure (4 bar) and feed temperature.


12

Page 13 of 34

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

RESULTS AND DISCUSSION Adsorption equilibrium isotherms Adsorption equilibrium data of CO2, N2, CH4 and H2 on MIL-125(Ti)_NH2 were determined at 303, 323 and 343 K in the pressure range of 0 to 7 bar. The adsorption equilibrium of CO was measured at the same three temperatures but in the pressure range of 0 to 3 bar. The experimental results are presented as points in Figure 5. The closed and open symbols represent respectively the points determined for adsorption and desorption. No hysteresis was observed for any of the adsorbates at the three different temperatures. The experimental adsorption equilibrium data was fitted by the Langmuir model:

q = q ,

(2)

where qi is the adsorbed amount of the component i, qm,i is the maximum adsorption capacity of the adsorbent for component i, Ki is the adsorption or Langmuir constant of component i, and P is the pressure. The Langmuir constant temperature dependency is expressed by the Van’t Hoff equation: K = K e(∆/ )

(3)

Where Ki0 is the adsorption constant at infinite temperature, (-∆H) is the heat of adsorption, Rg is the universal gas constant and T is the temperature of the system. The isotherm parameters for each component were obtained by minimizing the sum of squared absolute errors between the calculated and experimental values, and are presented in Table 5.


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

Page 14 of 34

Figure 5. Amount of a) CO2, b) CO, c) N2, d) CH4 and e) H2 adsorbed on MIL-125(Ti)_NH2: points - experimental (closed adsorption, open desorption) at 303 ( ), 323 ( ) and 343 K ( ); lines - Langmuir isotherm fitting.


14

Page 15 of 34

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

Table 5 - Fitting parameters of the Langmuir model for CO2, CO, N2, CH4 and H2 adsorption equilibrium on MIL-125(Ti)_NH2. Component

qm (mol kg-1)

Ki0 (bar-1)

(-∆H) (kJ mol-1)

CO2

8.509

5.782 × 10-5

21.9

CO

3.482

3.360 × 10-4

13.4

N2

5.377

2.807 × 10-4

11.7

CH4

7.093

2.422 × 10-4

14.6

H2

0.304

7.480 × 10-5

23.3

It is possible to observe the following order of adsorption: CO2>CH4>CO>N2>H2, from the most adsorbed to the less adsorbed. The adsorption capacity determined in this work is in agreement with results previously reported in the literature. Kim et al.32 determined the adsorption isotherms of CO2 from 273 to 303 K and of N2 at 298 K for an in house prepared MIL-125(Ti)_NH2. For the adsorption of CO2 at 1 bar and 303 K they reported a value of 2.7 mol/kg and for N2 at 1 bar and 298 K a value of 0.18 mol/kg. Both values are around 11% higher than the values determined in this study (respectively 2.4 and 0.16 mol/kg). In the case of CH4, Vaesen et. al35 determined an adsorption capacity of 1.25 mol/kg at 2 bar and 303 K which is around 17% higher than the value measured in this work (1.03 mol/kg). As in this study, a shaped adsorbent is being used, some loss in adsorption capacity is expected. Comparing the CO2 adsorption equilibrium isotherm of this material (303K) with isotherms reported for other MOFs in shaped form7,

18, 29

(298 to 308K) (see Figure S2 - Supporting

information), it can be observed that CuBTC and UTSA-16 present higher adsorption capacity than MIL-125(Ti)_NH2, and Mil-53 presents similar values. However, UTSA-16 has high


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

Page 16 of 34

capacity at low pressures which results in a lower working capacity for application in H2 purification processes. In this point, the linearity of the CuBTC, MIL-53 and MIL-125(Ti)_NH2 is advantageous. In respect to stability, MIL-125(Ti)_NH2 is more advantageous as it is more stable in the presence of humidity than CuBTC. Regarding the H2 adsorption capacity determined in this study, it is seen that the Mil-125(Ti)NH2 presents higher values than those reported for activated carbons8, 36 and zeolites8, 37, but in the same range as capacities previously reported for other MOFs7,

29, 38, 39

. A graphic that

compares the H2 adsorption equilibrium isotherm obtained in this work at 303 K with previously reported H2 adsorption equilibrium isotherms at similar temperatures (from 298 to 308 K) for other materials is presented in Figure S3 (Supporting information). The experimental isosteric heat of adsorption as function of the loading was determined using the Clausius-Clapeyron equation (4).40 (−∆H ) = R " T $ %

&'( ) & *

(4)

Under the assumption that the isosteric heat of adsorption values do not depend on temperature the following equation is obtained: ln(-. ) = −

(∆/0 ) 12

3

+5

(5)

where A is the integration constant. Representing ln (Pi) as function of 1/T for each loading, the corresponding isosteric heat of adsorption is obtained from the slope. The results obtained are presented in Figure 6, where they are also compared with the heats of adsorption obtained through the Langmuir isotherm model. A good agreement between the experimental and fitted values was found. In the results reported in Figure 5 a small increase of the values of the isosteric heats of adsorption is observed at low loadings which may indicate attractive lateral interactions between the adsorbed molecules.


16

Page 17 of 34

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

Figure 6. Single-component isosteric heats of adsorption on MIL-125(Ti)_NH2 for CO2 ( ), CH4 ( ), N2 ( ) and CO ( ) as a function of the amount adsorbed in the temperature range of 303-343 K; lines are the values obtained through the Langmuir fitting. The heat of adsorption determined in this work for CO2 is 21.9 kJ/mol which compares with 29.8 kJ/mol reported by Vaesen et. al35. Kim et al. 32 calculated the heat of adsorption of CO2 as function of the loading and obtained values ranging from 30 to 22 kJ/mol. In the case of CH4, Vaesen et. al35 determined a value of 18.8 kJ/mol, slightly higher than the value obtained in this study (14.6 kJ/mol). The value of the heat of adsorption calculated in this work for H2 (23.3 kJ/mol) is higher than expected. However, the order of magnitude of this value is in agreement with the average value of the isosteric heat of adsorption reported by Zhang et. al41 for MIL-53(Al)_NH2 (17.4 kJ/mol). Breakthrough curves Single, binary and ternary breakthrough curves were measured with the experimental conditions presented in Table 3 and Table S1. The fixed bed experimental data was compared with simulation results obtained with a mathematical model. The model employed describes fixed-bed adsorption for multicomponent mixtures, and it includes the mass, energy and momentum balances. Some assumptions were made to derive the model: ideal gas behavior


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 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 34

throughout the column; no mass, heat or velocity gradients are considered in the radial direction; axially dispersed plug flow; the external mass and heat transfer resistances expressed with the film model; internal mass transfer resistance expressed with the linear driving force model; no temperature gradients inside each particle since the heat transfer in the solid particles is higher than in the gas phase; constant porosity along the bed; the Ergun equation is valid locally. The model equations are given in Table S2. Further details about the mathematical model can be found elsewhere.5, 42 The mathematical model was implemented in gProms®.43 The orthogonal collocation on finite elements method with second order polynomials and 60 intervals was applied to solve the equations. The transport parameters used in the mathematical model were calculated at the feed conditions of each breakthrough experiment by commonly used correlations.5, 42, 44 The values of the transport parameters are given in Table S3. The results obtained for Runs BT1 to BT3 are shown respectively in Figures 7 to 9 and those for Runs BT4 to BT9 in Figures S4 through S9. In these figures, graphic (a) presents the molar flow rate of each component at the column outlet and graphic (b) shows the temperature history at the bottom (8.1 cm), middle (19.1 cm) and top (30 cm) positions in the column. The points are experimental data and the lines the simulation results. Run BT1 (Figure 7) corresponds to a single breakthrough curve of carbon dioxide. It can be seen that the molar flowrate and temperature histories obtained experimentally and predicted by simulation are in good agreement. A temperature increase of around 15 K is observed during adsorption for all thermocouples.


18

Page 19 of 34

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

Figure 7. Breakthrough curve results of Run BT1: a) CO2/He molar flow rate at the column outlet; b) temperatures histories in the column. Points correspond to experimental data and lines to simulation results. Vertical line corresponds to the beginning of desorption.

Figure 8 shows the results obtained for a CO2/H2 binary breakthrough curve. The simulation results given in this figure assume that there is no competitive adsorption between H2 and the other components, that is, the competitive adsorption capacities are calculated by the following equation: 9 :0 , C, D =@A 9= := >

6. ∗ = 68,. ;∑? 0

9K :KJ KJ :KJ M

= EF$ , EF, G$ , EHI; 6/J ∗ = 68,/J L9J

(5)


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

Page 20 of 34

Figure 8. Breakthrough curve results of Run BT2: a) CO2/H2 molar flow rate at the column outlet; b) temperatures histories in the column. Points correspond to experimental data and lines to simulation results. Vertical line corresponds to the beginning of desorption.

This hypothesis was considered because, if competitive adsorption of CO2 and H2 were calculated from the multicomponent extended Langmuir isotherm for all components, a significative difference between the experimental and simulation results would be observed (Figure S10). The simulation would predict a significant decrease of the adsorption capacity of CO2 due to the presence of H2, which is not observed experimentally. On the other hand, if one assumes that H2 does not adsorb (N. = 0), the simulation predicts well the CO2 front but the H2 front breaks through earlier than observed experimentally (Figure S11). When non-competitive adsorption is considered (Figure 8), the simulation predicts well the behavior of both compounds, including the breakthrough time of H2. This comparison shows that the hypothesis of no competitive adsorption between H2 and the other components represents better the experimental results and therefore was used to simulate all other runs.


20

Page 21 of 34

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

The results of a CO2/CO/H2 ternary breakthrough curve are reported in Figure 9. It can be seen that the experimental results are well predicted by the simulation confirming the hypothesis discussed above.

Figure 9. Breakthrough curve results of Run BT3: a) CO2/CO/H2 molar flow rate at the column outlet; b) temperatures histories in the column. Points correspond to experimental data and lines to simulation results. Vertical line corresponds to the beginning of desorption.

The results of two single breakthrough curves (H2 and CO), two binary breakthrough curves (CO2/CO and CO2/N2) and two ternary breakthrough curves (CO2/N2/H2 and CO2/CH4/H2) are given in supporting information. For all these results good agreement between the experimental and simulation data is observed.

PSA experiments Two PSA cycles were studied aiming two different scenarios. The objective of the first test (Run PSA1) was hydrogen purification from a CO2/H2 mixture. The cycle scheme used is shown in Figure 3 and the operating conditions in Table 4. The results


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

Page 22 of 34

obtained are shown in Figure 10 where in graphics a) and b) the molar flow rate of each component at the column outlet for cycles (1, 2 and 3) and (18) respectively are given, in graphic c) the temperature history at the bottom (8.1 cm), middle (19.1 cm) and top (30 cm) positions in the column is presented and in graphic d) the column pressure history is shown. Again, the points represent the experimental data and the lines the simulation results. The same mathematical model coupled with the appropriate boundary conditions for PSA simulation was employed.5, 42 In this cycle, pure hydrogen is produced during the feed step, while a CO2 enriched stream is obtained during the blowdown and purge steps. The temperature increases during the feed step and decreases during the blowdown. The experimental results in terms of molar flowrate, temperature and pressure are well predicted by the simulation. The process performance is evaluated according to three performance parameters: hydrogen purity, hydrogen recovery and productivity.45 For the cycle used in Run PSA 1, these parameters are calculated by: H$ Purity (%) =

Z

W^ [\\] XYJ _^ |a@ bc

(6)

Z

[\\] X _ | ∑d ^ a@ bc @A W^

H$ Recovery (%) =

Z

Z

W^ [\\] XYJ _^ |a@ bc W^ hij\ XYJ _^ |a@ bc Z

Z

W^ hj\

XYJ _^ |a@^ bcW^ [\\] XYJ _^ |a@^ bc

Productivity (mol kg

h ) =

qrsst

W^

(7)

q

pKJ u^ |v@w xy W^ z{|2s pKJ u^ |v@w xy y}~}s ×8 x xy

(8)

A hydrogen purity of 100%, a hydrogen recovery of 23.5% and a productivity of 2.8 molH2 kg-1 h-1 were obtained from the simulation results.


22

Page 23 of 34

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

Figure 10. PSA results of Run PSA1: a) molar flow rate at the column outlet for cycles 1, 2 and 3; b) molar flow rate at the column outlet for cycle 18, c) temperatures histories at 8.1 cm (bottom), 19.1 cm (middle) and 30 cm (top); d) pressure history. Points correspond to experimental data and lines to simulation results. Vertical lines indicate the duration of each step (pressurization, feed, blowdown and purge) along the cycles.

The purpose of the second PSA test (Run PSA2) was the adjustment of the syngas stream to a composition suitable to feed to a Fisher-Tropsch reactor and the production of an enriched CO2 stream. The cycle scheme used is shown in Figure 4 and the operating conditions in Table 4. Figure 11 presents the results obtained.


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

Page 24 of 34

Figure 11. PSA results of Run PSA2: a) molar flow rate at the column outlet for cycles 1, 2 and 3; b) molar flow rate at the column outlet for cycle 12, c) temperatures histories at 8.1 cm (bottom), 19.1 cm (middle) and 30 cm (top); d) pressure history. Points correspond to experimental data and lines to simulation results. Vertical lines indicate the duration of each step (pressurization, feed, blowdown and purge) along the cycles.

During the feed and rinse steps the (H2+CO) product is obtained and during the blowdown and purge steps the CO2 stream is produced. In the temperature history, two peaks are observed. One


24

Page 25 of 34

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

originated from the CO2 adsorption during the feed step, and the other from the increase in CO2 concentration from the rinse step. Once again the model predicts well the simulation results. In the case of Run PSA2, the process performance is assessed by the H2/CO stoichiometric ratio in the light product, the CO2 purity and recovery in the heavy product and the productivity, each calculated by: J

X

=

qrsst

W^

qrsst

W^

q

pKJ u^ |v@w W^ |0?s pKJ u^ |v@w

(9)

q

p u^ |v@w W^ |0?s p u^ |v@w

CO$ Purity (%) =

z{|2s

pJ u^ |v@^ xy q qz{|2s ? ∑0@A; W^ p0 u^ |v@^ xy W^ p0 u^ |v@^ xy > W^

CO$ Recovery (%) =

pJ u^ |v@^ xyW^

q

q

(10) q

W^ pJ u^ |v@^ xy W^ z{|2s pJ u^ |v@^ xy W^ |0?s pJ u^ |v@^ xy qrsst

q

W^ z|s pJ u^ |v@^ xyW^

pJ u^ |v@^ xy

(11)

H$ + CO Productivity (molJ X kg h ) =

qrsst

W^

q

q

pKJ u^ |v@w xy W^ |0?s pKJ u^ |v@w xy W^ z{|2s pKJ u^ |v@w xy y}~}s ×8 x xy

(12)

CO$ Productivity (molXJ kg h ) = q q q W pJ u^ |v@^ xy W^ z{|2s pJ u^ |v@^ xy W^ |0?s pJ u^ |v@^ xy

^

y}~}s ×8 x xy

(13)

In this test the following values were obtained for the performance parameters using the simulation results: H2/CO stoichiometric ratio of 2.3, CO2 purity of 86.6 %, CO2 recovery of 93.5% and productivities of 3.0 molCO2 kg-1 h-1 and 5.6 molH2+CO kg-1 h-1. Furthermore, in this case study, the inert fraction in the light is also an important constraint. A value of 3.0% was obtained which is below the 5% constraint.14 The PSA cycles were designed taking into consideration the limitations of the lab-scale experimental set-up, namely in terms of possible steps, flowrates and pressure, and therefore the


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

Page 26 of 34

processes performances are not optimized. However, the results obtained show the feasibility of using this adsorbent in PSA processes for syngas conditioning.

CONCLUSIONS The MOF MIL-125(Ti)_NH2 in the form of granulates was assessed for use in adsorptive separation processes for syngas treatment. The basic single adsorption equilibrium data necessary for the design of the PSA processes were measured for CO2, CH4, CO, N2 and H2. The material showed higher adsorption capacity for CO2 followed by CH4, CO, N2 and H2. Fixed-bed tests were performed to evaluate the multicomponent adsorption capacity and the adsorption kinetics. The results showed that the multicomponent adsorption of mixtures with hydrogen was not well described considering competition between hydrogen and all other adsorbates. The hypothesis that H2 adsorbs without competition and that the other compounds compete with each other was made. With this hypothesis the experimental data were successfully described by the model. Furthermore, the breakthrough curves presented fast increase of concentration (sharp concentration fronts) and easy desorption. It can therefore be concluded that the material does not present important mass transfer limitations. Two lab-scale PSA experiments were designed focusing on two main purposes: hydrogen purification and syngas composition adjustment with co-production of a CO2 enriched stream. For the first case study, a cycle with four steps, cocurrent pressurization, feed, blowdown, and purge was employed. Starting with a feed stream of 70%/30% of H2/CO2, a hydrogen product with 100% H2 and a recovery of 23.5% were obtained. For the second case study, a cycle with five steps, co-current pressurization, feed, rinse, blowdown and purge, was designed. Using a feed stream with 30% CO2, 22% CO and 48% H2, a light product with a H2/CO ratio of 2.3 and 3% of CO2 suitable as feed stream for a FT process


26

Page 27 of 34

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

was obtained. The other product of the process was a CO2 enriched stream with 86.6%. A CO2 recovery of 93.5% was attained. The feasibility of using this adsorbent in PSA processes for syngas purification was proven.

ASSOCIATED CONTENT SEM images of MIL-125(Ti)_NH2 granulates. Experimental conditions for breakthrough experiments BT4 to BT9. Comparison of CO2 adsorption equilibrium isotherms in shaped MOFs. Comparison of H2 adsorption equilibrium isotherms in different materials. Fixed-bed mathematical model. Transport parameters values for breakthrough experiments BT1 to BT9. Breakthrough curve results for BT4 to BT9. Breakthrough curve simulation results of Run BT2 with competitive adsorption for all components (including H2) and with KH2=0. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION Corresponding Author *To whom correspondence should be addressed: Ana M. Ribeiro: Phone + 351 22 041 4835; Fax: + 351 22 508 1674. E-mail: [email protected] Jong-San Chang: Phone +82 42 860 7673; Fax: +82 42 860 7673. E-mail: [email protected] Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes


27

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 28 of 34

The authors declare no competing financial interest. ACKNOWLEDGMENT The authors acknowledge financial support provided by Fundação para a Ciência e a Tecnologia (FCT, Portugal) and FEDER under Programme COMPETE through the Project EXPL/AAG-TEC/2205/2013.This work was co-financed by FCT/MEC and FEDER under Programme PT2020 (Project UID/EQU50020/2013). This work was also co-financed by QREN, ON2 and FEDER (Project NORTE-07-0124-FEDER-0000006). The Korean authors would like to acknowledge the financial support from the R&D Convergence Program of MSIP (Ministry of Science, ICT and Future Planning) and NST (National Research Council of Science & Technology) of Republic of Korea (CRC-14-1-KRICT).

REFERENCES 1.

Rostrup-Nielsen, J.; Christiansen, L. J., Concepts in Syngas Manufacture. Imperial

College Press: London, 2011. 2.

Wilhelm, D. J.; Simbeck, D. R.; Karp, A. D.; Dickenson, R. L., Syngas production for

gas-to-liquids applications: technologies, issues and outlook. Fuel Processing Technology 2001, 71, (1-3), 139-148. 3.

Ortiz, F. J. G.; Serrera, A.; Galera, S.; Ollero, P., Methanol synthesis from syngas

obtained by supercritical water reforming of glycerol. Fuel 2013, 105, 739-751. 4.

Martin, M.; Grossmann, I. E., Process Optimization of FT-Diesel Production from

Lignocellulosic Switchgrass. Industrial & Engineering Chemistry Research 2011, 50, (23), 13485-13499.


28

Page 29 of 34

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

5.

Ribeiro, A. M.; Grande, C. A.; Lopes, F. V. S.; Loureiro, J. M.; Rodrigues, A. E., Four

Beds Pressure Swing Adsorption for Hydrogen Purification: Case of Humid Feed and Activated Carbon Beds. Aiche Journal 2009, 55, (9), 2292-2302. 6.

You, Y. W.; Lee, D. G.; Yoon, K. Y.; Moon, D. K.; Kim, S. M.; Lee, C. H., H-2 PSA

purifier for CO removal from hydrogen mixtures. International Journal of Hydrogen Energy 2012, 37, (23), 18175-18186. 7.

Silva, B.; Solomon, I.; Ribeiro, A. M.; Lee, U. H.; Hwang, Y. K.; Chang, J. S.; Loureiro,

J. M.; Rodrigues, A. E., H-2 purification by pressure swing adsorption using CuBTC. Separation and Purification Technology 2013, 118, 744-756. 8.

Delgado, J. A.; Agueda, V. I.; Uguina, M. A.; Sotelo, J. L.; Brea, P.; Grande, C. A.,

Adsorption and Diffusion of H-2/CO, CH4, and CO2 in BPL Activated Carbon and 13X Zeolite: Evaluation of Performance in Pressure Swing Adsorption Hydrogen Purification by Simulation. Industrial & Engineering Chemistry Research 2014, 53, (40), 15414-15426. 9.

Luberti, M.; Friedrich, D.; Brandani, S.; Ahn, H., Design of a H-2 PSA for cogeneration

of ultrapure hydrogen and power at an advanced integrated gasification combined cycle with precombustion capture. Adsorption-Journal of the International Adsorption Society 2014, 20, (2-3), 511-524. 10.

Ribeiro, A. M.; Santos, J. C.; Rodrigues, A. E., Pressure swing adsorption for CO2

capture in Fischer-Tropsch fuels production from biomass. Adsorption-Journal of the International Adsorption Society 2011, 17, (3), 443-452. 11.

Sircar, S.; Golden, T. C., Purification of hydrogen by pressure swing adsorption.

Separation Science and Technology 2000, 35, (5), 667-687. 12.

Fuderer, A.; Rudelstorfer, E. Selective Adsorption Process. US Patent 3,986,849, 1976.


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

13.

Page 30 of 34

Koytsoumpa, E. I.; Atsonios, K.; Panopoulos, K. D.; Karellas, S.; Kakaras, E.; Karl, J.,

Modelling and assessment of acid gas removal processes in coal-derived SNG production. Applied Thermal Engineering 2015, 74, 128-135. 14.

Ribeiro, A. M.; Santos, J. C.; Rodrigues, A. E.; Rifflart, S., Pressure Swing Adsorption

Process in Coal to Fischer-Tropsch Fuels with CO2 Capture. Energy & Fuels 2012, 26, (2), 1246-1253. 15.

Ribeiro, A. M.; Santos, J. C.; Rodrigues, A. E.; Rifflart, S., Syngas Stoichiometric

Adjustment for Methanol Production and Co-Capture of Carbon Dioxide by Pressure Swing Adsorption. Separation Science and Technology 2012, 47, (6), 850-866. 16.

Farrusseng, D., Metal-Organic Frameworks: Applications from Catalysis to Gas Storage.

Wiley-VCH: University Lyon, France, 2011. 17.

Férey, G., Hybrid porous solids: past, present, future. Chem Soc Rev 2008, Volume 37,

(1), 191-214. 18.

Ferreira, A. F. P.; Ribeiro, A. M.; Kulac, S.; Rodrigues, A. E., Methane purification by

adsorptive processes on MIL-53(Al). Chemical Engineering Science 2015, 124, 79-95. 19.

Garcia, E. J.; Mowat, J. P. S.; Wright, P. A.; Perez-Pellitero, J.; Jallut, C.; Pirngruber, G.

D., Role of Structure and Chemistry in Controlling Separations of CO2/CH4 and CO2/CH4/CO Mixtures over Honeycomb MOFs with Coordinatively Unsaturated Metal Sites. Journal of Physical Chemistry C 2012, 116, (50), 26636-26648. 20.

Asadi, T.; Ehsani, M. R.; Ribeiro, A. M.; Loureiro, J. M.; Rodrigues, A. E., CO2/CH4

Separation by Adsorption using Nanoporous Metal organic Framework Copper-Benzene-1,3,5tricarboxylate Tablet. Chemical Engineering & Technology 2013, 36, (7), 1231-1239.


30

Page 31 of 34

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

21.

Ribeiro, A. M.; Campo, M. C.; Narin, G.; Santos, J. C.; Ferreira, A.; Chang, J. S.;

Hwang, Y. K.; Seo, Y. K.; Lee, U. H.; Loureiro, J. M.; Rodrigues, A. E., Pressure swing adsorption process for the separation of nitrogen and propylene with a MOF adsorbent MIL100(Fe). Separation and Purification Technology 2013, 110, 101-111. 22.

Plaza, M. G.; Ribeiro, A. M.; Ferreira, A.; Santos, J. C.; Hwang, Y. K.; Seo, Y. K.; Lee,

U. H.; Chang, J. S.; Loureiro, J. M.; Rodrigues, A. E., Separation of C3/C4 hydrocarbon mixtures by adsorption using a mesoporous iron MOF: MIL-100(Fe). Microporous and Mesoporous Materials 2012, 153, 178-190. 23.

Plaza, M. G.; Ribeiro, A. M.; Ferreira, A.; Santos, J. C.; Lee, U. H.; Chang, J. S.;

Loureiro, J. M.; Rodrigues, A. E., Propylene/propane separation by vacuum swing adsorption using Cu-BTC spheres. Separation and Purification Technology 2012, 90, 109-119. 24.

Bohme, U.; Barth, B.; Paula, C.; Kuhnt, A.; Schwieger, W.; Mundstock, A.; Caro, J.;

Hartmann, M., Ethene/Ethane and Propene/Propane Separation via the Olefin and Paraffin Selective Metal-Organic Framework Adsorbents CPO-27 and ZIF-8. Langmuir 2013, 29, (27), 8592-8600. 25.

Couck, S.; Liu, Y. Y.; Leus, K.; Baron, G. V.; Van der Voort, P.; Denayer, J. P. M., Gas

phase adsorption of alkanes, alkenes and aromatics on the sulfone-DUT-5 Metal Organic Framework. Microporous and Mesoporous Materials 2015, 206, 217-225. 26.

Trens, P.; Belarbi, H.; Shepherd, C.; Gonzalez, P.; Ramsahye, N. A.; Lee, U. H.; Seo, Y.

K.; Chang, J. S., Adsorption and separation of xylene isomers vapors onto the chromium terephthalate-based porous material MIL-101(Cr): An experimental and computational study. Microporous and Mesoporous Materials 2014, 183, 17-22.


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

27.

Page 32 of 34

Mendes, P. A. P.; Ragon, F.; Rodrigues, A. E.; Horcajada, P.; Serre, C.; Silva, J. A. C.,

Hexane isomers sorption on a functionalized metal-organic framework. Microporous and Mesoporous Materials 2013, 170, 251-258. 28.

Moreira, M. A.; Santos, J. C.; Ferreira, A. F. P.; Loureiro, J. M.; Ragon, F.; Horcajada,

P.; Yot, P. G.; Serre, C.; Rodrigues, A. E., Toward Understanding the Influence of Ethylbenzene in p-Xylene Selectivity of the Porous Titanium Amino Terephthalate MIL-125(Ti): Adsorption Equilibrium and Separation of Xylene Isomers. Langmuir 2012, 28, (7), 3494-3502. 29.

Agueda, V. I.; Delgado, J. A.; Uguina, M. A.; Brea, P.; Spjelkavik, A. I.; Blom, R.;

Grande, C., Adsorption and diffusion of H-2, N-2, CO, CH4 and CO2 in UTSA-16 metal-organic framework extrudates. Chemical Engineering Science 2015, 124, 159-169. 30.

Herm, Z. R.; Swisher, J. A.; Smit, B.; Krishna, R.; Long, J. R., Metal-Organic

Frameworks as Adsorbents for Hydrogen Purification and Precombustion Carbon Dioxide Capture. Journal of the American Chemical Society 2011, 133, (15), 5664-5667. 31.

Banu, A. M.; Friedrich, D.; Brandani, S.; Duren, T., A Multiscale Study of MOFs as

Adsorbents in H-2 PSA Purification. Industrial & Engineering Chemistry Research 2013, 52, (29), 9946-9957. 32.

Kim, S.-N.; Kim, J.; Kim, H.-Y.; Cho, H.-Y.; Ahn, W.-S., Adsorption/catalytic properties

of MIL-125 and NH2-MIL-125. Catalysis Today 2013, 204, (0), 85-93. 33.

Moreira, M. A.; Santos, J. C.; Ferreira, A. F. P.; Loureiro, J. M.; Ragon, F.; Horcajada,

P.; Yot, P. G.; Serre, C.; Rodrigues, A. E., Effect of ethylbenzene in p-xylene selectivity of the porous titanium amino terephthalate MIL-125(Ti)_NH2. Microporous and Mesoporous Materials 2012, 158, 229-234.


32

Page 33 of 34

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

34.

Ferreira, A. F. P.; Santos, J. C.; Plaza, M. G.; Lamia, N.; Loureiro, J. M.; Rodrigues, A.

E., Suitability of Cu-BTC extrudates for propane–propylene separation by adsorption processes. Chemical Engineering Journal 2011, 167, (1), 1-12. 35.

Vaesen, S.; Guillerm, V.; Yang, Q. Y.; Wiersum, A. D.; Marszalek, B.; Gil, B.; Vimont,

A.; Daturi, M.; Devic, T.; Llewellyn, P. L.; Serre, C.; Maurin, G.; De Weireld, G., A robust amino-functionalized titanium(IV) based MOF for improved separation of acid gases. Chemical Communications 2013, 49, (86), 10082-10084. 36.

Grande, C. A.; Lopes, F. V. S.; Ribeiro, A. M.; Loureiro, J. M.; Rodrigues, A. E.,

Adsorption of off-gases from steam methane reforming (H-2, CO2, CH4, CO and N-2) on activated carbon. Separation Science and Technology 2008, 43, (6), 1338-1364. 37.

Lopes, F. V. S.; Grande, C. A.; Ribeiro, A. M.; Loureiro, J. M.; Evaggelos, O.; Nikolakis,

V.; Rodrigues, A. E., Adsorption of H2, CO2, CH4, CO, N2 and H2O in Activated Carbon and Zeolite for Hydrogen Production. Separation Science and Technology 2009, 44, (5), 1045-1073. 38.

Saha, D. P.; Wei, Z. J.; Deng, S. G., Hydrogen adsorption equilibrium and kinetics in

metal-organic framework (MOF-5) synthesized with DEF approach. Separation and Purification Technology 2009, 64, (3), 280-287. 39.

Saha, D.; Wei, Z. J.; Deng, S. G., Equilibrium, kinetics and enthalpy of hydrogen

adsorption in MOF-177. International Journal of Hydrogen Energy 2008, 33, (24), 7479-7488. 40.

Do, D. D., Adsorption Analysis: Equilibria and Kinetics. Imperial College Press,

Department of Chemical Engineering: University of Queensland, Australia, 1998. 41.

Zhang, F.; Zou, X. Q.; Gao, X.; Fan, S. J.; Sun, F. X.; Ren, H.; Zhu, G. S., Hydrogen

Selective NH2-MIL-53(Al) MOF Membranes with High Permeability. Advanced Functional Materials 2012, 22, (17), 3583-3590.


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

42.

Page 34 of 34

Da Silva, F. A.; Silva, J. A.; Rodrigues, A. E., A General Package for the Simulation of

Cyclic Adsorption Processes. Adsorption-Journal of the International Adsorption Society 1999, 5, (3), 229-244. 43.

Process Systems Enterprise gPROMS. www.psenterprise.com/gproms (1997-2015).

44.

Bird, R. B.; Stewart, W. E.; Lightfoot, E. N., Transport Phenomena. Second ed.; Wiley

International: Singapore, 2002. 45.

Rota, R.; Wankat, P. C., Intensification of Pressure Swing Adsorption Processes. Aiche

Journal 1990, 36, (9), 1299-1312.


34

Syngas Purification by Porous Amino ... - ACS Publications

Recommend Documents