Novel Coal-Steam Gasification With a Thermochemical Regenerative Process for Power Generation

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Dandan Wang ◽  
Sheng Li ◽  
Lin Gao ◽  
Handong Wu ◽  
Hongguang Jin
Keyword(s):  
Energy Level ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Steam Gasification ◽  
Energy Utilization ◽  
Plant Performance ◽  
The Novel ◽  
Sensible Heat ◽  
Exergy Destruction ◽  
Separation Unit

In this paper, a novel high-efficiency coal gasification technology is proposed in which a regenerative unit is applied to recover syngas sensible heat to generate steam; then, the high-temperature steam is used to gasify coke from a pyrolyzer. Through such a thermochemical regenerative unit, the sensible heat with a lower energy level is upgraded into syngas chemical energy with a higher energy level; therefore, high cold gas efficiency (CGE) is expected from the proposed system. aspenplus software is selected to simulate the novel coal gasification system, and the key parameters are validated by experimentation. Then energy, exergy, and energy-utilization diagram (EUD) analyses are applied to disclose the plant performance enhancement mechanism. It is revealed that 83.2% of syngas sensible heat can be recovered into steam agent with the CGE upgraded to 90%. In addition, with the enhancement of CGE, the efficiency of an integrated gasification combined cycle (IGCC) based on the novel gasification system can be as high as 51.82%, showing a significant improvement compared to 45.2% in the general electric company (GE) gasification-based plant. In the meantime, the irreversible destruction of the gasification procedure is reduced to 25.7% through thermochemical reactions. The increase in the accepted energy level (Aea) and the decreases in the released energy level (Aed) and heat absorption (ΔH) contribute to the reduction in exergy destruction in the gasification process. Additionally, since the oxygen agent is no longer used in the IGCC, 34.5 MW exergy destruction in the air separation unit (ASU) is avoided.

A Novel Coal Gasification System Through Thermochemical Regenerative Process of Syngas Sensible Heat to Enhance Cold Gas Efficiency

2017 ◽  
Author(s):  
Dandan Wang ◽  
Sheng Li ◽  
Lin Gao
Keyword(s):  
Energy Level ◽  
Coal Gasification ◽  
The Novel ◽  
Sensible Heat ◽  
Exergy Destruction ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Gas Efficiency ◽  
Gasification Technology ◽  
Cold Gas

In this paper, a novel coal gasification technology used for Integrated Gasification Combined Cycle (IGCC) power plants is proposed, in which a regenerative unit is applied to recover syngas sensible heat to generate steam and then the high temperature steam is used to gasify coke from pyrolyzer. Through such a thermochemical regenerative unit, the sensible heat with lower energy level is upgraded into syngas chemical energy with higher energy level, and therefore a higher cold gas efficiency (CGE) is expected. The Aspen Plus Software is selected to simulate the novel coal gasification system. Then the exergy and Energy-Utilization Diagram (EUD) analyses are applied to disclose the plant performance enhancement mechanism. It reveals that 83.2% of syngas sensible heat can be recovered into steam agent and so the CGE is upgraded to 90%. And with the enhancement of CGE, the efficiency of an IGCC plant based on the novel gasification system can be as high as 51.82%, showing a significant improvement compared to 45.2% in a Texaco coal gasification based plant. At the same time, the exergy destruction of gasification process is reduced from 132.5MW to 98.4MW through thermochemical reactions. Lift of accepted energy level (Aea), and decrease of released energy level (Aed) and heat absorption (ΔH) contribute to the exergy destruction reduction in the gasification process. Additionally, since oxygen agent is no longer used in the IGCC, 34.5MW exergy loss in the air separation unit is avoided. Thereby the novel coal gasification technology proposed in this paper has a good thermodynamic performance and may provide a quite promising way for high efficient and clean coal utilization.

Exergy Destruction Mechanism of Coal Gasification by Combining the Kinetic Method and the Energy Utilization Diagram

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Handong Wu ◽  
Sheng Li ◽  
Lin Gao
Keyword(s):  
Chemical Reactions ◽  
Coal Gasification ◽  
Kinetic Method ◽  
Steam Gasification ◽  
Energy Utilization ◽  
Exergy Destruction ◽  
Steam Content ◽  
Carbon Gasification ◽  
Destruction Mechanism ◽  
Gasification Reaction

Gasification is the core unit of coal-based production systems and is also the site where one of the largest exergy destruction occurs. This paper reveals the exergy destruction mechanism of carbon gasification through a combined analysis of the kinetic method and the energy utilization diagram (EUD). Instead of a lumped exergy destruction using the traditional “black-box” and other models, the role of each reaction in carbon gasification is revealed. The results show that the exergy destruction caused by chemical reactions accounts for 86.3% of the entire carbon gasification process. Furthermore, approximately 90.3% of exergy destruction of chemical reactions is caused by the exothermal carbon partial oxidation reaction (reaction 1), 6.0% is caused by the carbon dioxide gasification reaction (reaction 2), 2.4% is caused by the steam gasification reaction (reaction 3), and 1.3% is caused by other reactions under the base condition. With increasing O2 content α and decreasing steam content β, the proportion of exergy destruction from reaction 1 decreases due to the higher gasification temperature (a higher energy level of energy acceptor in EUD), while the proportions of other reactions increase. This shows that the chemical efficiency is optimal when the extent of reactions 1 and 3 is equal and the shift reaction extent approaches zero at the same time.

scholarly journals Experimental Study and Thermodynamic Analysis of Hydrogen Production through a Two-Step Chemical Regenerative Coal Gasification

2019 ◽  
Vol 9 (15) ◽  
pp. 3035 ◽  
Author(s):  
Li ◽  
He ◽  
Li
Keyword(s):  
Hydrogen Production ◽  
Production Process ◽  
Coal Gasification ◽  
Fixed Bed ◽  
H2 Production ◽  
Steam Gasification ◽  
Air Separation ◽  
The Novel ◽  
Separation Unit ◽  
Gasification Process

Hydrogen, as a strategy clean fuel, is receiving more and more attention recently in China, in addition to the policy emphasis on H2. In this work, we conceive of a hydrogen production process based on a chemical regenerative coal gasification. Instead of using a lumped coal gasification as is traditional in the H2 production process, herein we used a two-step gasification process that included coking and char-steam gasification. The sensible heat of syngas accounted for 15–20% of the total energy of coal and was recovered and converted into chemical energy of syngas through thermochemical reactions. Moreover, the air separation unit was eliminated due to the adoption of steam as oxidant. As a result, the efficiency of coal to H2 was enhanced from 58.9% in traditional plant to 71.6% in the novel process. Further, the energy consumption decreased from 183.8 MJ/kg in the traditional plant to 151.2 MJ/kg in the novel process. The components of syngas, H2, and efficiency of gasification are herein investigated through experiments in fixed bed reactors. Thermodynamic performance is presented for both traditional and novel coal to hydrogen plants.

A GCC Power Plant With Methanol Storage for Intermediate-Load Duty

1991 ◽  
Vol 113 (1) ◽  
pp. 151-157 ◽  
Author(s):  
J. A. Paffenbarger
Keyword(s):  
Power Plant ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Production Costs ◽  
Plant Performance ◽  
Electricity Production ◽  
Fuel Prices ◽  
Electrical Demand ◽  
Integrated Facility ◽  
Plant Configuration

This paper describes the design and performance of a coal gasification combined-cycle power plant with an integrated facility for producing and storing methanol (GCC/methanol power plant). The methanol is produced at a steady rate and is burned in the combined cycle to generate additional power during periods of peak electrical demand. The GCC/methanol plant provides electricity generation and energy storage in one coal-based facility. It is of potential interest to electric utilities seeking to meet intermediate-load electrical demand on their systems. The plant configuration is determined by means of an innovative economic screening methodology considering capital and fuel costs over a range of cycling duties (capacity factors). Estimated levelized electricity production costs indicate that a GCC/methanol plant could be of economic interest as premium fuel prices increase relative to coal. The plant could potentially be of interest for meeting daily peak demands for periods of eight hours or less. The conceptual plant configuration employs a Texaco gasifier and a Lurgi methanol synthesis plant. Plant performance is estimated at peak and baseload output levels. No unusual design or operational problems were identified.

A GCC Power Plant With Methanol Storage for Intermediate-Load Duty

1990 ◽  
Author(s):  
John A. Paffenbarger
Keyword(s):  
Power Plant ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Production Costs ◽  
Plant Performance ◽  
Electricity Production ◽  
Fuel Prices ◽  
Electrical Demand ◽  
Integrated Facility ◽  
Plant Configuration

This paper describes the design and performance of a coal gasification combined-cycle power plant with an integrated facility for producing and storing methanol (GCC/methanol power plant). The methanol is produced at a steady rate and is burned in the combined-cycle to generate additional power during periods of peak electrical demand. The GCC/methanol plant provides electricity generation and energy storage in one coal-based facility. It is of potential interest to electric utilities seeking to meet intermediate-load electrical demand on their systems. The plant configuration is determined by means of an economic screening study considering capital and fuel costs over a range of cycling duties (load factors). Estimated levelized electricity production costs indicate that a GCC/methanol plant could be of economic interest as premium fuel prices increase relative to coal. The plant could potentially be of interest for meeting daily peak demands for periods of eight hours or less. The conceptual plant configuration employs a Texaco gasifier and a Lurgi methanol synthesis plant. Plant performance is estimated at peak and baseload output levels. No unusual design or operational problems were identified.

System Study on Partial Gasification Combined Cycle With CO2 Recovery

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Yujie Xu ◽  
Hongguang Jin ◽  
Rumou Lin ◽  
Wei Han
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
The Novel ◽  
Integrated Gasification Combined Cycle ◽  
Partial Gasification ◽  
Co2 Recovery

A partial gasification combined cycle with CO2 recovery is proposed in this paper. Partial gasification adopts cascade conversion of the composition of coal. Active composition of coal is simply gasified, while inactive composition, that is char, is burnt in a boiler. Oxy-fuel combustion of syngas produces only CO2 and H2O, so the CO2 can be separated through cooling the working fluid. This decreases the amount of energy consumption to separate CO2 compared with conventional methods. The novel system integrates the above two key technologies by injecting steam from a steam turbine into the combustion chamber of a gas turbine to combine the Rankine cycle with the Brayton cycle. The thermal efficiency of this system will be higher based on the cascade utilization of energy level. Compared with the conventional integrated gasification combined cycle (IGCC), the compressor of the gas turbine, heat recovery steam generator (HRSG) and gasifier are substituted for a pump, reheater, and partial gasifier, so the system is simplified obviously. Furthermore, the novel system is investigated by means of energy-utilization diagram methodology and provides a simple analysis of their economic and environmental performance. As a result, the thermal efficiency of this system may be expected to be 45%, with CO2 recovery of 41.2%, which is 1.5–3.5% higher than that of an IGCC system. At the same time, the total investment cost of the new system is about 16% lower than that of an IGCC. The comparison between the partial gasification technology and the IGCC technology is based on the two representative cases to identify the specific feature of the proposed system. The promising results obtained here with higher thermal efficiency, lower cost, and less environmental impact provide an attractive option for clean-coal utilization technology.

Improved Performance and Reduced Emission From Coal and Gas Fuelled GT-SOFC and GT-MCFC Plants: Some Studies

2006 ◽  
Author(s):  
S. Ghosh ◽  
S. De ◽  
S. Saha
Keyword(s):  
Natural Gas ◽  
Emission Reduction ◽  
Coal Gasification ◽  
Energy Savings ◽  
Combined Cycle ◽  
Plant Performance ◽  
Co2 Emission Reduction ◽  
Simulated Performance ◽  
Combined Cycle Plant ◽  
Improved Performance

This paper presents conceptual models of some novel GT-SOFC and GT-MCFC plants for power and cogeneration operating on gasified coal or natural gas. Simulated performance of the modeled plants in terms of energy efficiency, emission reduction, fuel energy savings (for cogeneration) with respect to separate reference plants for power generation and utility heat production is presented and analyzed. Influences of variations in some design and operating parameters on the plant performance are also reported in the paper. A study with a coal gasification combined cycle plant using SOFC upstream of GT suggests that such plants have the potential of delivering power at an overall efficiency level exceeding 50%. A similar plant delivering both power and utility heat can potentially save about 30% of fuel with respect to separate plants for power and heat. For a conceptualized natural gas fuelled GT-MCFC CHP plant, an electrical efficiency of more than 40% and fuel energy saving exceeding, 30% are achievable. Using a CO2 separator placed at fuel cell exhaust, CO2 can be trapped in a closed cycle. CO2 emission reduction as high as 60% is achievable for such plants.

Effect of Fuel Gas Cleanup Option on Air-Blown IGCC Power Plant Performance

1997 ◽  
Author(s):  
W. C. Yang ◽  
R. A. Newby ◽  
R. L. Bannister
Keyword(s):  
Power Plant ◽  
Process Model ◽  
Coal Gasification ◽  
Heat Rate ◽  
Combined Cycle ◽  
Plant Performance ◽  
Fuel Gas ◽  
Gas Cleaning ◽  
Plant Sensitivity ◽  
Parametric Studies

Air-blown coal gasification for combined-cycle power generation is a technology soon to be demonstrated. A process evaluation of air-blown IGCC performed to estimate the plant heat rate, electrical output and potential emissions are described in this paper. A process model of an air-blown IGCC power system based on the Westinghouse 501F combustion turbine was developed to conduct the performance evaluation. Parametric studies were performed to develop an understanding of the power plant sensitivity to the major operating parameters and process options. Advanced hot fuel gas cleaning and conventional cold fuel gas cleaning options were both considered.

System Study on Partial Gasification Combined Cycle With CO2 Recovery

2006 ◽  
Author(s):  
Yujie Xu ◽  
Hongguang Jin ◽  
Rumou Lin ◽  
Wei Han
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
The Novel ◽  
Attractive Option ◽  
Partial Gasification ◽  
Co2 Recovery

A partial gasification combined cycle with CO2 recovery is proposed in this paper. Partial gasification adopts cascade conversion of the composition of coal. Active composition of coal is simply gasified, while inactive composition, that is char, is burnt in a boiler. Oxy-fuel combustion of syngas produces only CO2 and H2O, so the CO2 can be separated through cooling the working fluid. This decreases the amount of energy consumed to separate CO2 compared with conventional methods. The novel system integrates the above two key technologies, by injecting steam from a steam turbine into the combustion chamber of a gas turbine, to combine the Rankine cycle with the Brayton cycle. The thermal efficiency of this system will be higher based on the cascade utilization of energy level. Compared to the conventional IGCC, the compressor of the gas turbine, HRSG and gasifier are substituted for a pump, reheater and partial gasifier, so the system is simplified obviously. Furthermore, the novel system is investigated by means of EUD (Energy-Utilization Diagram) methodology and provides a simple analysis of their economic and environmental performance. As a result, the thermal efficiency of this system may be expected to be 46%, with recovery of 50% of CO2, which is 3–5% higher than that of an IGCC system. At the same time, the total investment cost of the new system is about 21.5% lower than that of an IGCC. The promising results obtained here with higher thermal efficiency, lower cost and less environmental impact provide an attractive option for clean coal utilization technology.

Exergy Analysis of Integration Between Air Separation Process and IGCC

2000 ◽  
Author(s):  
Zelong Liu ◽  
Hongguang Jin ◽  
Rumou Lin
Keyword(s):  
Gas Turbine ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Air Separation ◽  
Exergy Destruction ◽  
Steam Generation ◽  
Separation Unit ◽  
Air Compressor ◽  
Nitrogen Injection ◽  
Air Separation Unit

Abstract Integrated Gasification Combined Cycle (IGCC) is considered as one of the advanced clean coal power technologies. Here, we have investigated an IGCC with air separation unit (ASU) on the basis of exergy analysis, and clarified the distribution of exergy destruction in sub-systems including air separation unit, coal gasifier, coal gas clean-up unit, air compressor, combustor of gas turbine, gas turbine, heat recovery steam generation and steam turbine. Particularly, we have focused on the interaction between the ASU and the gas turbine (GT). The results obtained disclosed the significant role of the integration between air separation unit and air compressor in the GT, and the effect of nitrogen injection to the combustor on IGCC overall performance. The study also points out that larger exergy destruction take place in the processes of gasification, combustion in GT, and air separation, and so does the change of exergy destruction distribution with the air integration degree and the nitrogen injection ratio. We have demonstrated the potential for improving the IGCC system. This investigation will be valuable for the synthesis of next-generation IGCC.

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