A Coal-Fueled Combustion Turbine Cogeneration System With Topping Combustion

1997 ◽  
Vol 119 (1) ◽  
pp. 84-92 ◽  
Author(s):  
J. M. Bee´r ◽  
R. V. Garland

Cogeneration systems fired with coal or other solid fuels and containing conventional extracting-condensing or back pressure steam turbines can be found throughout the world. A potentially more economical plant of higher output per unit thermal energy is presented that employs a pressurized fluidized bed (PFB) and coal carbonizer. The carbonizer produces a char that is fed to the PFB and a low heating value fuel gas that is utilized in a topping combustion system. The topping combustor provides the means for achieving state-of-the-art turbine inlet temperatures and is the main contributor to enhancing the plant performance. An alternative to this fully coal-fired system is the partially coal, partially natural gas-fired air heater topping combustion cycle. In this cycle compressed air is preheated in an atmospheric pressure coal-fired boiler and its temperature raised further by burning natural gas in a topping gas turbine combustor. The coal fired boiler also generates steam for use in a cogeneration combined cycle. The conceptual design of the combustion turbine is presented with special emphasis on the low-emissions multiannular swirl burner topping combustion system and its special requirements and features.

Author(s):  
Thormod Andersen ◽  
Hanne M. Kvamsdal ◽  
Olav Bolland

A concept for capturing and sequestering CO2 from a natural gas fired combined cycle power plant is presented. The present approach is to decarbonise the fuel prior to combustion by reforming natural gas, producing a hydrogen-rich fuel. The reforming process consists of an air-blown pressurised auto-thermal reformer that produces a gas containing H2, CO and a small fraction of CH4 as combustible components. The gas is then led through a water gas shift reactor, where the equilibrium of CO and H2O is shifted towards CO2 and H2. The CO2 is then captured from the resulting gas by chemical absorption. The gas turbine of this system is then fed with a fuel gas containing approximately 50% H2. In order to achieve acceptable level of fuel-to-electricity conversion efficiency, this kind of process is attractive because of the possibility of process integration between the combined cycle and the reforming process. A comparison is made between a “standard” combined cycle and the current process with CO2-removal. This study also comprise an investigation of using a lower pressure level in the reforming section than in the gas turbine combustor and the impact of reduced steam/carbon ratio in the main reformer. The impact on gas turbine operation because of massive air bleed and the use of a hydrogen rich fuel is discussed.


2014 ◽  
Vol 492 ◽  
pp. 568-573 ◽  
Author(s):  
Yinka Sofihullahi Sanusi ◽  
Palanichamy Gandhidasan ◽  
Esmail M.A. Mokheimer

Saudi Arabia is blessed with abundant solar energywhichcan be use to meet its ever increasing power requirement. In this regard, the energy analysis and plant performance of integrated solar combined cycle (ISCC) plant with direct steam generation (DSG) was carried out for Dhahran, Saudi Arabia using four representative months of March, June, September and December. The plant consists of 180MW conventional gas turbine plant and two steam turbines of 80MW and 60MW powered by the solar field and gas turbine exhaust. With high insolation during the summer month of June the plant can achieve up to 25% of solar fraction with ISCC plant efficiency of 45% as compared to gas turbine base of 38%.This can however be improved by increasing the number of collectors or/and the use of auxiliary heater .


Author(s):  
Yan Xiong ◽  
Lucheng Ji ◽  
Zhedian Zhang ◽  
Yue Wang ◽  
Yunhan Xiao

Gas turbine is one of the key components for integrated gasification combined cycle (IGCC) system. Combustor of the gas turbine needs to burn medium/low heating value syngas produced by coal gasification. In order to save time and cost during the design and development of a gas turbine combustor for medium/low heating value syngas, computational fluid dynamics (CFD) offers a good mean. In this paper, 3D numerical simulations were carried out on a full scale multi-nozzle gas turbine combustor using commercial CFD software FLUENT. A 72 degrees sector was modeled to minimize the number of cells of the grid. For the fluid flow part, viscous Navier-Stokes equations were solved. The realizable k-ε turbulence model was adopted. Steady laminar flamelet model was used for the reacting system. The interaction between fluid turbulence and combustion chemistry was taken into account by the PDF (probability density function) model. The simulation was performed with two design schemes which are head cooling using film-cooling and impingement cooling. The details of the flow field and temperature distribution inside the two gas turbine combustors obtained could be cited as references for design and retrofit. Similarities were found between the predicted and experimental data of the transition duct exit temperature profile. There is much work yet to be done on modeling validation in the future.


Author(s):  
Carmine Russo ◽  
Giulio Mori ◽  
Vyacheslav V. Anisimov ◽  
Joa˜o Parente

Chemical Reactor Modelling approach has been applied to evaluate exhaust emissions of the newly designed ARI100 (Patent Pending) recuperated micro gas turbine combustor developed by Ansaldo Ricerche SpA. The development of the chemical reactor network has been performed based on CFD reacting flow analysis, obtained with a global 2-step reaction mechanism, applying boundary conditions concerning the combustion chamber at atmospheric pressure, with 100% of thermal load and fuelled with natural gas. The network consists of 11 ideal reactors: 6 perfectly stirred reactors, and 5 plug flow reactors, including also 13 mixers and 12 splitters. Simulations have been conducted using two detailed reaction mechanisms: GRI Mech 3.0 and Miller & Bowman reaction mechanisms. Exhaust emissions have been evaluated at several operating conditions, obtained at different pressure, and considering different fuel gases, as natural gas and a high H2 content SYNGAS fuel. Furthermore, emissions at different thermal loads have been investigated when natural gas at atmospheric pressure is fuelled. Simulation results have been compared with those obtained from combustion experimental campaign. CO and NOx emissions predicted with CRM approach closely match experimental results at representative operating conditions. Ongoing efforts to improve the proposed reactors network should allow extending the range of applicability to those operating conditions whose simulation results are not completely satisfying. Given the small computational effort required, and the accuracy in predicting combustor experimental exhaust emissions, both CO and NOx, the CRM approach turnout to be an efficient way to reasonably evaluate exhaust emissions of a micro gas turbine combustor.


Author(s):  
Kenneth O. Smith ◽  
Leonard C. Angello ◽  
F. Richard Kurzynske

The design and initial rig testing of an ultra-low NOx gas turbine combustor primary zone are described. A lean premixed, swirl-stabilized combustor was evaluated over a range of pressures up to 10.7 × 105 Pa (10.6 atm) using natural gas. The program goal of reducing NOx emissions to 10 ppm (at 15% O2) with coincident low CO emissions was achieved at all combustor pressure levels. Appropriate combustor loading for ultra-low NOx operation was determined through emissions sampling within the primary zone. The work described represents a first step in developing an advanced gas turbine combustion system that can yield ultra-low NOx levels without the need for water injection and selective catalytic reduction.


Author(s):  
S. Ghosh ◽  
S. De ◽  
S. Saha

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.


1999 ◽  
Vol 122 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Richard A. Newby ◽  
Wen-Ching Yang ◽  
Ronald L. Bannister

Fuel gas cleanup processing significantly influences overall performance and cost of IGCC power generation. The raw fuel gas properties (heating value, sulfur content, alkali content, ammonia content, “tar” content, particulate content) and the fuel gas cleanup requirements (environmental and turbine protection) are key process parameters. Several IGCC power plant configurations and fuel gas cleanup technologies are being demonstrated or are under development. In this evaluation, air-blown, fluidized-bed gasification combined-cycle power plant thermal performance is estimated as a function of fuel type (coal and biomass fuels), extent of sulfur removal required, and the sulfur removal technique. Desulfurization in the fluid bed gasifier is combined with external hot fuel gas desulfurization, or, alternatively with conventional cold fuel gas desulfurization. The power plant simulations are built around the Siemens Westinghouse 501F combustion turbine in this evaluation. [S0742-4795(00)00502-0]


Author(s):  
W. C. Yang ◽  
R. A. Newby ◽  
R. L. Bannister

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.


2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Shi Liu ◽  
Hong Yin ◽  
Yan Xiong ◽  
Xiaoqing Xiao

Heavy duty gas turbines are the core components in the integrated gasification combined cycle (IGCC) system. Different from the conventional fuel for gas turbine such as natural gas and light diesel, the combustible component acquired from the IGCC system is hydrogen-rich syngas fuel. It is important to modify the original gas turbine combustor or redesign a new combustor for syngas application since the fuel properties are featured with the wide range hydrogen and carbon monoxide mixture. First, one heavy duty gas turbine combustor which adopts natural gas and light diesel was selected as the original type. The redesign work mainly focused on the combustor head and nozzle arrangements. This paper investigated two feasible combustor arrangements for the syngas utilization including single nozzle and multiple nozzles. Numerical simulations are conducted to compare the flow field, temperature field, composition distributions, and overall performance of the two schemes. The obtained results show that the flow structure of the multiple nozzles scheme is better and the temperature distribution inside the combustor is more uniform, and the total pressure recovery is higher than the single nozzle scheme. Through the full scale test rig verification, the combustor redesign with multiple nozzles scheme is acceptable under middle and high pressure combustion test conditions. Besides, the numerical computations generally match with the experimental results.


Author(s):  
E. Toombs ◽  
T. Stowell ◽  
N. Austin ◽  
P. Danyluk

In 1996 Cabot Corporation begun development of engines capable of burning the off-gas from a pyrolysis process used to make carbon black. The fuel gas comes off the process at near atmospheric pressure, high temperature, and saturated with water. After de-watering the gas composition was approximately 16–20% Hydrogen, 16–20% Carbon Monoxide, 1–3% Sulfur compounds and the rest Nitrogen and water. Dewatered heating value of the fuel was around 3350–3720 kJ/nm3. Many engine configurations including both spark and oil ignited were evaluated to utilize this low energy fuel. The paper describes the development cycle and the early experience at commercialization at three sites.


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