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Design of Co-gasification from Coal and Biomass Combined heat and Power Generation System
Available online at www.sciencedirect.com
ScienceDirect Energy Procedia 75 (2015) 1120 – 1125
The 7th International Conference on Applied Energy – ICAE2015
Design of co-gasification from coal and biomass combined heat and power generation system Po-Chih Kuo, Wei Wu* Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
Abstract The objective of this work focuses on designing a co-gasification process using Aspen Plus. The effect of cogasification of coal/ torrefied biomass blends of 0, 20, 40, 60, 80, 100% w/w torrefied biomass content was evaluated. To evaluate the potential application of torrefied wood, an integration of co-gasification with CHP (combined heat and power) plant for heat and electric power production is also carried out in this simulation model. The simulation result shows that the gas turbine provided 1352.55 kW net power output and the efficiency up to 58.94 % when the BR ratio of 80 wt% is conducted. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2015 The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and/or peer-review under responsibility of ICAE Peer-review under responsibility of Applied Energy Innovation Institute Keywords: Co-gasification; Biomass; Heat and power generation; Aspen Plus
1. Introduction Gasification is a thermochemical process for producing higher calorific values gas such as hydrogen, carbon monoxide, carbon dioxide, methane, and other hydrocarbons. However, the coal gasification produces more pollutant (H2S, SOx and NOx) that cause a significant impact on environment. Compared to the coal gasification, co-gasification of coal and biomass may be a way to the solution of the aforementioned problems. Biomass is characterized as low nitrogen and sulphur, which causes reductions of nitric oxide (NOx) and sulfur dioxide (SOx) by comparing to coal. In addition, biomass is considered as a carbon-neutral fuel
* Corresponding author. Tel.: +886 62344496. E-mail address: [email protected].
1876-6102 © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of Applied Energy Innovation Institute doi:10.1016/j.egypro.2015.07.523
Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
which produces little net CO2 emission to the environment. For this reason, coal may be replaced partially by biomass, which is a method to reduce the pollutant emission [1]. Recently, torrefied biomass also has been considered for its feasibility to replace raw biomass and coal. Since torrefied biomass has remarkable advantages such as lower moisture, higher energy density, improved grindability, and becoming a more uniform fuel [2]. In this work, a design of co-gasification of coal and torrefied biomass is developed by Aspen Plus. To evaluate the effect on syngas yield along with the steam-to-fuel mass ratio. Moreover, a combination of co-gasification and CHP ( combined heat and power) plant for power generation is also developed in this study. 2. System modeling 2.1. Co-gasification process Fig.1 shows a schematic co-gasification process. As a whole, the model included several sub-units for simulating co-gasification process. Firstly, the stream of fuels (stream 1), including biomass, coal or their blends of a ratio of 20, 40, 60 and 80% w/w, respectively are fed into the system. After drying, the fuels are decomposed into its elemental constituents in the block RYield. In this block, the unconventional stream (stream 2) transforms from an unconventional solid into volatiles and char (stream 3). The volatiles consist of carbon, hydrogen, oxygen, nitrogen, and sulphur. The cogasification is simulated by a block called RGibbs, in which the chemical equilibrium calculations are performed by minimizing the Gibbs free energy. With regard to the gasifying agents, water (stream 4) is heated in the block Heater to become steam (stream 5). The product gas is divided into two streams product gas (stream 8) and char (stream 9), in the block SSPLIT. Afterwards, the product gas passes through to the separator block to simulate the removal of acid gases (stream 11) from the product gas. To achieve 99.95+% purity of hydrogen, the pressure swing adsorption (PSA) technology was connected to the separator block. Therefore, the excess air (stream 14) flow is directly fed into the burner to react with waste gas (stream 13), and the flue gas (stream 15) can be used to generate power in the next section. 2.2 Power generation process After burning the waste gas from co-gasification section, the high temperature flue gas is obtained and is used to heat the feedwater (stream 16) in the steam generator. Therefore, the steam is produced in a serious of heat exchangers composed of the radiant water-wall evaporator, the radiant superheater and the economizer. The process description is shown as Figure 2 where the power generation system major consists of steam generator and Rankine cycle. Firstly, the saturated water (stream 16) passes through a water pump, where the w is pressurized from 1 to 240 atm and is heated sequentially through feedwater heaters and steam generator. The steam flow is obtained with a supercritical state of 600°C at 240 atm, (stream 18), and the steam then enters into the high-pressure turbine where it expands and runs a generator, which produces electricity (W1). After expanding, an outlet pressure of 49 atm is obtained (stream 19). Secondly, a few steam (stream 20) is piped to feedwater heaters, most steam (stream 21) flows continues to steam generator. Thirdly, the stream 22 enters into intermediate-pressure turbines and exhausted to low-pressure turbines (stream 23 and stream 24). As a result, the pressure of steam finally drops from 49 to 0.5 atm, and the temperature of flue gas drops to 300°C through heat exchange with feedwater. Finally, the steam passes through a water-cooled condenser in order to recirculate to the steam boiler (stream 25). 3. Results and discussion
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Bituminous (Ensham mine, Australia), raw woody biomass, and torrfied woody biomass at the temperature of 300 °C are selected to compare the gasification performance firstly. Then, the effect of cogasification of coal/ torrefied biomass blends of 0, 20, 40, 60, 80, 100% w/w torrefied biomass content is evaluated. The properties of the feedstock, such as the results of the proximate analysis, elemental analysis, and higher heating values (HHV) are listed in Table 3 [3]. The gasification process is performed at 700 °C and 1 atm [4-6]. The major chemical reactions occurring in the gasifier are listed in Table 2 [78]. Two parameters of steam-to-fuel ratio (S/F) and biomass ratio (BR) are taken into account to investigate the performance of co-gasification. They are defined as follows: S/F
The mass flow rate of steam ( kg / hr ) The mass flow rate of fuel ( kg / hr )
Biomass feed ( kg / hr ) Total fuel feed ( kg / hr ) Figure 3 presents the effect of different fuels on gas composition. From Figure 3(a), it can be seen that the addition of steam has a positive effect on the H2 formation, in that it monotonically increases along with the S/F ratio. This behavior can be explained by the water gas reaction (R5). Notably, both coal and torrefied woody biomass show a significant increase when the S/C ratio is over 1.0. However, the coal has a significantly higher carbon content compared to both the raw and torrefied woody biomass, resulting that the H2 formation is the highest among the three fuels. From Figure 3(b), it can be seen that the maximum CO amount of coal, raw and torrefied woody biomass are located at the S/F ratio of 0.4, 0.8 and 1.4, respectively. This may be due to the shift reaction where the generated CO further reacts with steam to produce CO2 and H2 (R7). Therefore, more CO2 is produced for raw woody biomass than in the gasification of coal and torrefied woody biomass. Moreover, the bioamss has a higher oxygen content compared to coal. This also causes higher production of CO2 when the bioamss is used as feedstock. Figure 3(d) shows that high CH4 amount is observed for coal due to the methanation reaction. According to the results, torrfied woody biomass has a larger amount in syngas formation and thus is selected as feedstock to blend with coal for co-gasification and power generation. Figure 4(a) presents the effect of different BR ratio on turbine net power generation. It can be seen that different BR ratio has an optimal S/F ratio. For example, the gas turbine provided 1352.55 kW net power output at S/F ratio of 0.9 when the BR ratio is 80 wt% is conducted. However, the lower BR ratio is conducted and the more steam is needed to inject the system in order to reach maximum power generation. This implies that co-gasification with torrefied woody biomass is a way to significantly improve the power generation and reduce the pollutant emission to surroundings. With regard to power generation efficiency, Figure 4(b) shows that the system efficiency of coal blending with torrefied woody biomass is higher than that of coal when the S/F ratio is below 1.0. The maximum system efficiency is 58.94 when the BR ratio is 80 wt% is conducted. BR (%)
4. Conclusion In this article, the design of co-gasification of coal and biomass combined heat and power generation system is verified by Aspen Plus simulation. The simulation shows that using the torrefied woody biomass as an alternative to raw woody biomass can significantly improve syngas yield. From the view point of power generation, co-gasification of coal and torrefied biomass has been observed which can be found an optimal input condition in terms of power generation and system efficiency.
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Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
Table 1. Proximate and elemental analyses of the feedstock used in the simulation [3]. Feedstocks
Proximate analysis (wt%) Moisture Volatile matter (VM) Fixed carbon (FC) Ash Elemental analysis (wt%) C H N S O* Higher heating value (MJ kg-1) * By difference Reaction
Bituminous coal
Woody biomass
Torrefied woody biomass at 300 Ʊ C
6.67 27.25 54.50 11.58
3.81 88.72 7.42 0.05
2.81 67.58 29.36 0.25
74.12 4.22 1.91 0.41 6.93 26.69
46.73 6.46 0.41 0 46.35 18.42
59.03 4.78 0.34 0 35.59 22.52
Table 2. A list of chemical reactions in the gasifier [7-8]. Process
Reaction number R1
Drying
H 2 O l o H 2 O g , ' H 0
Devolatilization
CH x O y N z o char volatile gases
R2
Oxidation
C 0.5 O2 o CO, 'H 0
R3 R4
C O2 o CO2 , 'H 0
40 .7 kJ mol 1
268 kJ mol 1 406 kJ mol 1
Water gas reaction
C H 2O o CO H 2 , 'H 0
Boudouard reaction
C CO2 o 2 CO, 'H 0
Shift reaction
CO H 2 O l CO2 H 2 , 'H 0
Methanation reaction
C 2 H 2 l CH 4 , 'H 0
131.4 kJ mol 1
172.6 kJ mol 1 75 kJ mol 1
CO 3H 2 l CH 4 H 2O, 'H 0
Figure 1 Flow chart of the co-gasification system.
42 kJ mol 1 206 kJ mol 1
R5 R6 R7 R8 R9
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Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
Figure 2 Flow chart of the power generation system. (a) H 2
(b) CO
100
60 Coal Torrefied Raw
Coal Torrefied Raw
80
CO (kmol/hr)
H 2 (kmol/hr)
40
60
20 40
0.5
1
0
1.5
0.5
S/F
(c) CO2
1.5
(d) CH 4
30
25
1
S/F
8 Coal Torrefied Raw
Coal Torrefied Raw
CH 4 (kmol/hr)
CO 2 (kmol/hr)
6 20
15
4
10 2 5
0
0.5
1
S/F
1.5
0
0.5
1
1.5
S/F
Figure 3 Effects of the S/F ratio on product distribution of (a) H2, (b) CO (c) CO2 and (d) CH4
Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
(a)
(b)
2000
100
80
1000 0% 20% 40% 60% 80% 100%
500
0
0.5
1
1.5
S/F
Efficiency (%)
Power (kw)
1500
60
40
0% 20% 40% 60% 80% 100%
20
0
0.5
1
1.5
S/F
Figure 4 Effects of the S/F ratio on (a) turbine net power generation and (b) system efficiency during cogasification of coal and torrefied woody biomass. Acknowledgements The authors would like to thank the Ministry of Science and Technology of the Republic of China for its partial financial support of this research under grant MOST 103-2221-E-006-251. References [1] Valero A, Uson S. Oxy-co-gasification of coal and biomass in an integrated gasification combined cycle (IGCC) power plant. ,Energy. Vol. 31, pp. 1643-1655, 2006. [2] Chew, J.J.; Doshi, V. Recent advances in biomass pretreatment-Torrefaction fundamentals and Technology. Renew Sust Energ Rev 2011,15, 4212-4222. [3] Park SW, Jang CH , Baek KR , Yang JK .Torrefaction and low-temperature carbonization of woody biomass: Evaluation of fuel characteristics of the products. ,Energy. Vol. 45, pp. 676-685, 2012. [4] Chaudhari, S.T.; Bej, S.K.; Bakhshi, N.N.; Dalai, A.K. Steam Gasification of Biomass-Derived Char for the Production of Carbon Monoxide-Rich Synthesis Gas. Energ Fuel 2001,15, 736-742. [5] Yan, F.; Luo, S.Y.; Hu. Z.Q.; Xiao. B.; Cheng, G. Hydrogen-rich gas production by steam gasification of char from biomass fast pyrolysis in a fixed-bed reactor: Influence of temperature and steam on hydrogen yield and syngas composition. Bioresour Technol 2010,101, 5633-5637. [6] Nipattummakul, N.; Ahmed, II.; Kerdsuwan, S.; Gupta, A.K. Steam gasification of oil palm trunk waste for clean syngas production. Appl Energ 2012,92, 778-782. [7] Taba, L.E.; Irfan, M.F.; Daud, W.A.M.W. Chakrabarti MH. The effect of temperature on various parameters in coal, biomass and CO-gasification: A review. Renewable and Sustainable Energy Rev 2012,16, 5584-5596. [8] Gao, N.; Li. A.; Quan, C.; Gao, F. Hydrogen-rich gas production from biomass steam gasification in an updraft fixed-bed gasifier combined with a porous ceramic reformer. Int J of Hydrogen Energ 2008,33, 5430-5438.
Biography Wei Wu is a professor of Chemical Engineering at National Cheng Kung University, Taiwan since 2011. He received a B.S. from Feng Chia University in 1988 and a M.S. from National Taiwan University of Science and Technology in 1990. He received his Ph.D from National Taiwan University of Science and Technology in 1995. His research interests include process control, chemical process integration and optimization and renewable energy system designs.
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ScienceDirect Energy Procedia 75 (2015) 1120 – 1125
The 7th International Conference on Applied Energy – ICAE2015
Design of co-gasification from coal and biomass combined heat and power generation system Po-Chih Kuo, Wei Wu* Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
Abstract The objective of this work focuses on designing a co-gasification process using Aspen Plus. The effect of cogasification of coal/ torrefied biomass blends of 0, 20, 40, 60, 80, 100% w/w torrefied biomass content was evaluated. To evaluate the potential application of torrefied wood, an integration of co-gasification with CHP (combined heat and power) plant for heat and electric power production is also carried out in this simulation model. The simulation result shows that the gas turbine provided 1352.55 kW net power output and the efficiency up to 58.94 % when the BR ratio of 80 wt% is conducted. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license © 2015 The Authors. Published by Elsevier Ltd. (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and/or peer-review under responsibility of ICAE Peer-review under responsibility of Applied Energy Innovation Institute Keywords: Co-gasification; Biomass; Heat and power generation; Aspen Plus
1. Introduction Gasification is a thermochemical process for producing higher calorific values gas such as hydrogen, carbon monoxide, carbon dioxide, methane, and other hydrocarbons. However, the coal gasification produces more pollutant (H2S, SOx and NOx) that cause a significant impact on environment. Compared to the coal gasification, co-gasification of coal and biomass may be a way to the solution of the aforementioned problems. Biomass is characterized as low nitrogen and sulphur, which causes reductions of nitric oxide (NOx) and sulfur dioxide (SOx) by comparing to coal. In addition, biomass is considered as a carbon-neutral fuel
* Corresponding author. Tel.: +886 62344496. E-mail address: [email protected].
1876-6102 © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of Applied Energy Innovation Institute doi:10.1016/j.egypro.2015.07.523
Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
which produces little net CO2 emission to the environment. For this reason, coal may be replaced partially by biomass, which is a method to reduce the pollutant emission [1]. Recently, torrefied biomass also has been considered for its feasibility to replace raw biomass and coal. Since torrefied biomass has remarkable advantages such as lower moisture, higher energy density, improved grindability, and becoming a more uniform fuel [2]. In this work, a design of co-gasification of coal and torrefied biomass is developed by Aspen Plus. To evaluate the effect on syngas yield along with the steam-to-fuel mass ratio. Moreover, a combination of co-gasification and CHP ( combined heat and power) plant for power generation is also developed in this study. 2. System modeling 2.1. Co-gasification process Fig.1 shows a schematic co-gasification process. As a whole, the model included several sub-units for simulating co-gasification process. Firstly, the stream of fuels (stream 1), including biomass, coal or their blends of a ratio of 20, 40, 60 and 80% w/w, respectively are fed into the system. After drying, the fuels are decomposed into its elemental constituents in the block RYield. In this block, the unconventional stream (stream 2) transforms from an unconventional solid into volatiles and char (stream 3). The volatiles consist of carbon, hydrogen, oxygen, nitrogen, and sulphur. The cogasification is simulated by a block called RGibbs, in which the chemical equilibrium calculations are performed by minimizing the Gibbs free energy. With regard to the gasifying agents, water (stream 4) is heated in the block Heater to become steam (stream 5). The product gas is divided into two streams product gas (stream 8) and char (stream 9), in the block SSPLIT. Afterwards, the product gas passes through to the separator block to simulate the removal of acid gases (stream 11) from the product gas. To achieve 99.95+% purity of hydrogen, the pressure swing adsorption (PSA) technology was connected to the separator block. Therefore, the excess air (stream 14) flow is directly fed into the burner to react with waste gas (stream 13), and the flue gas (stream 15) can be used to generate power in the next section. 2.2 Power generation process After burning the waste gas from co-gasification section, the high temperature flue gas is obtained and is used to heat the feedwater (stream 16) in the steam generator. Therefore, the steam is produced in a serious of heat exchangers composed of the radiant water-wall evaporator, the radiant superheater and the economizer. The process description is shown as Figure 2 where the power generation system major consists of steam generator and Rankine cycle. Firstly, the saturated water (stream 16) passes through a water pump, where the w is pressurized from 1 to 240 atm and is heated sequentially through feedwater heaters and steam generator. The steam flow is obtained with a supercritical state of 600°C at 240 atm, (stream 18), and the steam then enters into the high-pressure turbine where it expands and runs a generator, which produces electricity (W1). After expanding, an outlet pressure of 49 atm is obtained (stream 19). Secondly, a few steam (stream 20) is piped to feedwater heaters, most steam (stream 21) flows continues to steam generator. Thirdly, the stream 22 enters into intermediate-pressure turbines and exhausted to low-pressure turbines (stream 23 and stream 24). As a result, the pressure of steam finally drops from 49 to 0.5 atm, and the temperature of flue gas drops to 300°C through heat exchange with feedwater. Finally, the steam passes through a water-cooled condenser in order to recirculate to the steam boiler (stream 25). 3. Results and discussion
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Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
Bituminous (Ensham mine, Australia), raw woody biomass, and torrfied woody biomass at the temperature of 300 °C are selected to compare the gasification performance firstly. Then, the effect of cogasification of coal/ torrefied biomass blends of 0, 20, 40, 60, 80, 100% w/w torrefied biomass content is evaluated. The properties of the feedstock, such as the results of the proximate analysis, elemental analysis, and higher heating values (HHV) are listed in Table 3 [3]. The gasification process is performed at 700 °C and 1 atm [4-6]. The major chemical reactions occurring in the gasifier are listed in Table 2 [78]. Two parameters of steam-to-fuel ratio (S/F) and biomass ratio (BR) are taken into account to investigate the performance of co-gasification. They are defined as follows: S/F
The mass flow rate of steam ( kg / hr ) The mass flow rate of fuel ( kg / hr )
Biomass feed ( kg / hr ) Total fuel feed ( kg / hr ) Figure 3 presents the effect of different fuels on gas composition. From Figure 3(a), it can be seen that the addition of steam has a positive effect on the H2 formation, in that it monotonically increases along with the S/F ratio. This behavior can be explained by the water gas reaction (R5). Notably, both coal and torrefied woody biomass show a significant increase when the S/C ratio is over 1.0. However, the coal has a significantly higher carbon content compared to both the raw and torrefied woody biomass, resulting that the H2 formation is the highest among the three fuels. From Figure 3(b), it can be seen that the maximum CO amount of coal, raw and torrefied woody biomass are located at the S/F ratio of 0.4, 0.8 and 1.4, respectively. This may be due to the shift reaction where the generated CO further reacts with steam to produce CO2 and H2 (R7). Therefore, more CO2 is produced for raw woody biomass than in the gasification of coal and torrefied woody biomass. Moreover, the bioamss has a higher oxygen content compared to coal. This also causes higher production of CO2 when the bioamss is used as feedstock. Figure 3(d) shows that high CH4 amount is observed for coal due to the methanation reaction. According to the results, torrfied woody biomass has a larger amount in syngas formation and thus is selected as feedstock to blend with coal for co-gasification and power generation. Figure 4(a) presents the effect of different BR ratio on turbine net power generation. It can be seen that different BR ratio has an optimal S/F ratio. For example, the gas turbine provided 1352.55 kW net power output at S/F ratio of 0.9 when the BR ratio is 80 wt% is conducted. However, the lower BR ratio is conducted and the more steam is needed to inject the system in order to reach maximum power generation. This implies that co-gasification with torrefied woody biomass is a way to significantly improve the power generation and reduce the pollutant emission to surroundings. With regard to power generation efficiency, Figure 4(b) shows that the system efficiency of coal blending with torrefied woody biomass is higher than that of coal when the S/F ratio is below 1.0. The maximum system efficiency is 58.94 when the BR ratio is 80 wt% is conducted. BR (%)
4. Conclusion In this article, the design of co-gasification of coal and biomass combined heat and power generation system is verified by Aspen Plus simulation. The simulation shows that using the torrefied woody biomass as an alternative to raw woody biomass can significantly improve syngas yield. From the view point of power generation, co-gasification of coal and torrefied biomass has been observed which can be found an optimal input condition in terms of power generation and system efficiency.
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Table 1. Proximate and elemental analyses of the feedstock used in the simulation [3]. Feedstocks
Proximate analysis (wt%) Moisture Volatile matter (VM) Fixed carbon (FC) Ash Elemental analysis (wt%) C H N S O* Higher heating value (MJ kg-1) * By difference Reaction
Bituminous coal
Woody biomass
Torrefied woody biomass at 300 Ʊ C
6.67 27.25 54.50 11.58
3.81 88.72 7.42 0.05
2.81 67.58 29.36 0.25
74.12 4.22 1.91 0.41 6.93 26.69
46.73 6.46 0.41 0 46.35 18.42
59.03 4.78 0.34 0 35.59 22.52
Table 2. A list of chemical reactions in the gasifier [7-8]. Process
Reaction number R1
Drying
H 2 O l o H 2 O g , ' H 0
Devolatilization
CH x O y N z o char volatile gases
R2
Oxidation
C 0.5 O2 o CO, 'H 0
R3 R4
C O2 o CO2 , 'H 0
40 .7 kJ mol 1
268 kJ mol 1 406 kJ mol 1
Water gas reaction
C H 2O o CO H 2 , 'H 0
Boudouard reaction
C CO2 o 2 CO, 'H 0
Shift reaction
CO H 2 O l CO2 H 2 , 'H 0
Methanation reaction
C 2 H 2 l CH 4 , 'H 0
131.4 kJ mol 1
172.6 kJ mol 1 75 kJ mol 1
CO 3H 2 l CH 4 H 2O, 'H 0
Figure 1 Flow chart of the co-gasification system.
42 kJ mol 1 206 kJ mol 1
R5 R6 R7 R8 R9
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Figure 2 Flow chart of the power generation system. (a) H 2
(b) CO
100
60 Coal Torrefied Raw
Coal Torrefied Raw
80
CO (kmol/hr)
H 2 (kmol/hr)
40
60
20 40
0.5
1
0
1.5
0.5
S/F
(c) CO2
1.5
(d) CH 4
30
25
1
S/F
8 Coal Torrefied Raw
Coal Torrefied Raw
CH 4 (kmol/hr)
CO 2 (kmol/hr)
6 20
15
4
10 2 5
0
0.5
1
S/F
1.5
0
0.5
1
1.5
S/F
Figure 3 Effects of the S/F ratio on product distribution of (a) H2, (b) CO (c) CO2 and (d) CH4
Po-Chih Kuo and Wei Wu / Energy Procedia 75 (2015) 1120 – 1125
(a)
(b)
2000
100
80
1000 0% 20% 40% 60% 80% 100%
500
0
0.5
1
1.5
S/F
Efficiency (%)
Power (kw)
1500
60
40
0% 20% 40% 60% 80% 100%
20
0
0.5
1
1.5
S/F
Figure 4 Effects of the S/F ratio on (a) turbine net power generation and (b) system efficiency during cogasification of coal and torrefied woody biomass. Acknowledgements The authors would like to thank the Ministry of Science and Technology of the Republic of China for its partial financial support of this research under grant MOST 103-2221-E-006-251. References [1] Valero A, Uson S. Oxy-co-gasification of coal and biomass in an integrated gasification combined cycle (IGCC) power plant. ,Energy. Vol. 31, pp. 1643-1655, 2006. [2] Chew, J.J.; Doshi, V. Recent advances in biomass pretreatment-Torrefaction fundamentals and Technology. Renew Sust Energ Rev 2011,15, 4212-4222. [3] Park SW, Jang CH , Baek KR , Yang JK .Torrefaction and low-temperature carbonization of woody biomass: Evaluation of fuel characteristics of the products. ,Energy. Vol. 45, pp. 676-685, 2012. [4] Chaudhari, S.T.; Bej, S.K.; Bakhshi, N.N.; Dalai, A.K. Steam Gasification of Biomass-Derived Char for the Production of Carbon Monoxide-Rich Synthesis Gas. Energ Fuel 2001,15, 736-742. [5] Yan, F.; Luo, S.Y.; Hu. Z.Q.; Xiao. B.; Cheng, G. Hydrogen-rich gas production by steam gasification of char from biomass fast pyrolysis in a fixed-bed reactor: Influence of temperature and steam on hydrogen yield and syngas composition. Bioresour Technol 2010,101, 5633-5637. [6] Nipattummakul, N.; Ahmed, II.; Kerdsuwan, S.; Gupta, A.K. Steam gasification of oil palm trunk waste for clean syngas production. Appl Energ 2012,92, 778-782. [7] Taba, L.E.; Irfan, M.F.; Daud, W.A.M.W. Chakrabarti MH. The effect of temperature on various parameters in coal, biomass and CO-gasification: A review. Renewable and Sustainable Energy Rev 2012,16, 5584-5596. [8] Gao, N.; Li. A.; Quan, C.; Gao, F. Hydrogen-rich gas production from biomass steam gasification in an updraft fixed-bed gasifier combined with a porous ceramic reformer. Int J of Hydrogen Energ 2008,33, 5430-5438.
Biography Wei Wu is a professor of Chemical Engineering at National Cheng Kung University, Taiwan since 2011. He received a B.S. from Feng Chia University in 1988 and a M.S. from National Taiwan University of Science and Technology in 1990. He received his Ph.D from National Taiwan University of Science and Technology in 1995. His research interests include process control, chemical process integration and optimization and renewable energy system designs.
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