Development of Gas Steam and Power Multi-Generation System

Author(s):  
Mengxiang Fang ◽  
Qinghui Wang ◽  
Chunjiang Yu ◽  
Zhenglun Shi ◽  
Zhongyang Luo ◽  
...  

A new system using combined coal gasification and combustion has been developed for clean and high efficient utilization of coal. The coal is first gasified by air/steam or recycle gas and the produced fuel gas is then used for industrial purpose or as a fuel for gas turbine. The char residue from the gasifier is burned in a circulating fluidized bed combustor to generate steam for power generation. A 1MW pilot plant test facility has been erected, which consists of a fluidized bed gasifier, a CFB combustor, flue gas and fuel gas clean and cool system, data acqisition and control system. The primary results show that the system can produce 12–14MJ/Nm3 middle heating value gas by using recycle gas or steam as gasification mediaand bed temperature and solid circulation rate are main parameters. On bases of this, a 25 MW gas steam and power multi-generation system has been designed. In this system, a fluidized bed gasifiers are combined with a 130t/h circulating bed boiler to realize gas and steam cogeneration. The system can produce 7800 M3/h gas with heating value 10–14 Mj/Nm3 and 25 MW Power.

Author(s):  
Hongcang Zhou ◽  
Baosheng Jin ◽  
Zhaoping Zhong ◽  
Rui Xiao ◽  
Yaji Huang

More growing particular attentions are being paid to polycyclic aromatic hydrocarbons (PAHs) generated from coal gasification due to their high mutagenic and carcinogenic. Fluidized bed air and steam gasification of three different rank coals were studied in a bench-scale atmospheric fluidized bed test facility. An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 PAHs specified by US EPA in raw coal, slag, bag house char, cyclone char and fuel gas. The profiles and TEQ concentrations of PAHs emission from fluidized bed coal gasification were discussed. The results indicated that there were mainly three- and four-ringed PAHs in raw coal and fuel gas, but the total PAHs in bag house char and cyclone char were dominated by three-, four- and five-ringed PAHs. The concentrations of three-ringed PAHs in fuel gas were higher than those of four-ringed PAHs, but a reverse phenomenon occurred in bag house char and cyclone char. No PAHs were measured in slag during coal gasification. The total TEQ concentration of five-ringed PAHs mainly dominated in raw coal, fuel gas, bag house char, and cyclone char, and their percentages were about 75–96% by weight. Benzo(a)pyrene (BaP) was the main contributor of TEQ concentration in raw coal and gasified products. In addition, the concentration of PAHs in raw coal increased with the rise of coal rank, and there was not an obvious variation about the concentration of PAHs in gasified products.


1983 ◽  
Vol 105 (2) ◽  
pp. 348-353 ◽  
Author(s):  
D. E. Wright ◽  
L. L. Tignac

Rocketdyne is under contract to the Department of Energy for the development of heat exchanger technology that will allow coal to be burned for power generation and cogeneration applications. This effort involves both atmospheric fluidized bed and pulverized coal combustion systems. In addition, the heat exchanger designs cover both metallic and ceramic materials for high-temperature operations. This paper reports on the laboratory and small AFB test results completed to date. It also covers the design and installation of a 6×6 ft atmospheric fluidized bed test facility being used to correlate and expand the knowledge gained from the initial tests. The paper concludes by showing the direction this technology is taking and outlining the steps to follow in subsequent programs.


1994 ◽  
Vol 116 (2) ◽  
pp. 345-351 ◽  
Author(s):  
A. Robertson ◽  
D. Bonk

In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149°C (2100°F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871°C (1600°F), permitting sulfur capture by time-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.


Author(s):  
D. E. Wright ◽  
L. L. Tignac

Rocketdyne is under contract to DOE for the development of heat-exchanger technology that will allow coal to be burned for power generation and cogeneration applications. This effort involves both atmospheric fluidized bed and pulverized coal combustion systems. In addition, the heat-exchanger designs cover both metallic and ceramic materials for high temperature operations. This paper reports on the laboratory and small AFB test results completed to date. It also covers the design and installation of a 6 × 6 ft-atmospheric fluidized bed test facility being used to correlate and expand the knowledge gained from the initial tests. The paper concludes by showing the direction this technology is taking and outlining the steps to follow in subsequent programs.


2015 ◽  
Vol 17 (1) ◽  
pp. 66-78 ◽  
Author(s):  
Naveed Ramzan ◽  
Muhammad Athar ◽  
Sharmina Begum ◽  
Syed Waqas Ahmad ◽  
Shahid Naveed

Abstract A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV) of synthesis gas (Syn. Gas) to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.


Author(s):  
Robert A. Battista ◽  
Alan S. Feitelberg ◽  
Michael A. Lacey

General Electric Company is developing and testing low heating value fuel gas turbine combustors for use in integrated gasification combined cycle power generation systems. This paper presents the results of a series of combustion tests conducted at the pilot scale coal gasification and high temperature desulfurization system located at GE Corporate Research and Development in Schenectady, New York. Tests were performed in a modified GE MS6000 combustor liner operating at a pressure of 10 bar and over a wide load range (combustor exit temperatures from 760 to 1400°C). The primary objective of these tests was to compare and contrast the performance (emissions, flame stability, and combustor liner temperatures) of six different low heating value fuel nozzle designs, representing three distinct nozzle concepts. With 2200 to 4600 ppmv NH3 in the fuel, the conversion of fuel NH3 to NOx was roughly independent of fuel nozzle type, and ranged from about 70% at low combustor exit temperatures to about 20% at high combustor exit temperatures. For all of the fuel nozzles, CO emissions were typically less than 5 ppmv (on a dry, 15% O2 basis) at combustor exit temperatures greater than 980°C. Significant differences in CO emissions were observed at lower combustor exit temperatures. Some differences in liner temperatures and flame stability were also observed with the different nozzles. In general, nozzles which produced lower CO emissions and greater flame stability had higher fuel swirl angles and resulted in higher combustor liner temperatures. The nozzle with the best overall performance (consisting of concentric axial air and fuel swirlers and an air cooled mixing cup) has been selected for use at a commercial site.


Author(s):  
Archie Robertson ◽  
Donald Bonk

In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149°C (2100°F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871°C (1600°F), permitting sulfur capture by lime-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.


Author(s):  
Zhaoping Zhong ◽  
Baosheng Jin ◽  
Yaji Huang ◽  
Hongcang Zhou ◽  
Davide Ross ◽  
...  

This paper presents the results of coal gasification in a fluidized bed test rig of Xuzhou bituminous coal. The diameter of the fluidized bed combustor is 0.1m and the height is 4.22m. The bed temperature is maintained by a method of high temperature flue gas interline heating to overcome high heat losses associated with a oil burner. Test results are reported for variations in the bed temperature, air to coal, steam to coal and Ca to S ratio and their influence on gas yields and desulphurization efficiency. The distribution of polycyclic aromatic hydrocarbons (PAHs) and heavy metal trace elements into the char and syngas are also presented. The molar contents for CH4 and H2 in the coal syngas are found to decrease with increasing air to coal feed ratio from 2.5 to 5, while the content of CO shows little variation. Increasing the steam to coal feed ratio from 0.4 to 0.65 results in all three of the main gas components measured to form a local maximum content at a steam/coal feed ratio of 0.55. The efficiency of desulphurization improves as the ratio of Ca to S, air to coal and the bed temperature are increased, while decreasing with increasing steam to coal feed ratios. The volatile trace element species in decreasing order of relative mass ratio released into the gas phase are Hg, Se, As, Co, Cr, Cd, Cu, and Zn. Besides Hg, Se, and As, for all other trace heavy metals the majority of their mass distribution remains within the char with the proportion contained within char always greater than their combined yields in the coal syngas and slag. The total PAHs in the coal syngas is greater than that contained in the original coal and this indicates that PAHs are formed during the coal gasification process.


2021 ◽  
Vol 5 (2) ◽  
pp. 20
Author(s):  
Mateus Paiva ◽  
Admilson Vieira ◽  
Helder T. Gomes ◽  
Paulo Brito

In the evaluation of gasification processes, estimating the composition of the fuel gas for different conditions is fundamental to identify the best operating conditions. In this way, modeling and simulation of gasification provide an analysis of the process performance, allowing for resource and time savings in pilot-scale process operation, as it predicts the behavior and analyzes the effects of different variables on the process. Thus, the focus of this work was the modeling and simulation of biomass gasification processes using the UniSim Design chemical process software, in order to satisfactorily reproduce the operation behavior of a downdraft gasifier. The study was performed for two residual biomasses (forest and agricultural) in order to predict the produced syngas composition. The reactors simulated gasification by minimizing the free energy of Gibbs. The main operating parameters considered were the equivalence ratio (ER), steam to biomass ratio (SBR), and gasification temperature (independent variables). In the simulations, a sensitivity analysis was carried out, where the effects of these parameters on the composition of syngas, flow of syngas, and heating value (dependent variables) were studied, in order to maximize these three variables in the process with the choice of the best parameters of operation. The model is able to predict the performance of the gasifier and it is qualified to analyze the behavior of the independent parameters in the gasification results. With a temperature between 850 and 950 °C, SBR up to 0.2, and ER between 0.3 and 0.5, the best operating conditions are obtained for maximizing the composition of the syngas in CO and H2.


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