Chemical-Looping Combustion of Hard Coal: Autothermal Operation of a 1 MWth Pilot Plant

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Peter Ohlemüller ◽  
Jan-Peter Busch ◽  
Michael Reitz ◽  
Jochen Ströhle ◽  
Bernd Epple
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Capture ◽  
Oxygen Carrier ◽  
Air Separation ◽  
Capture Efficiency ◽  
Chemical Looping Combustion ◽  
Hard Coal ◽  
Chemical Looping ◽  
Separation Unit ◽  
Autothermal Operation

Chemical-looping combustion (CLC) is an emerging carbon capture technology that is characterized by a low energy penalty, low carbon dioxide capture costs, and low environmental impact. To prevent the contact between fuel and air, an oxygen carrier is used to transport the oxygen needed for fuel conversion. In comparison to a classic oxyfuel process, no air separation unit is required to provide the oxygen needed to burn the fuel. The solid fuel, such as coal, is gasified in the fuel reactor (FR), and the products from gasification are oxidized by the oxygen carrier. There are promising results from the electrically heated 100 kWth unit at Chalmers University of Technology (Sweden) or the 1 MWth pilot at Technische Universität Darmstadt (Germany) with partial chemical-looping conditions. The 1 MWth CLC pilot consists of two interconnected circulating fluidized bed reactors. It is possible to investigate this process without electrically heating due to refractory-lined reactors and coupling elements. This work presents the first results of autothermal operation of a metal oxide CLC unit worldwide using ilmenite as oxygen carrier and coarse hard coal as fuel. The FR was fluidized with steam. The results show that the oxygen demand of the FR required for a complete conversion of unconverted gases was in the range of 25%. At the same time, the carbon dioxide capture efficiency was low in the present configuration of the 1 MWth pilot. This means that unconverted char left the FR and burned in the air reactor (AR). The reason for this is that no carbon stripper unit was used during these investigations. A carbon stripper could significantly enhance the carbon dioxide capture efficiency.

Chemical Looping Combustion Using the Direct Combustion of Liquid Metal in a Gas Turbine Based Cycle

2010 ◽  
Author(s):  
Niall R. McGlashan ◽  
Peter R. N. Childs ◽  
Andrew L. Heyes
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Combined Cycle ◽  
Air Separation ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Sensible Heat ◽  
Separation Unit

A combined cycle gas turbine generating power and hydrogen is proposed and evaluated. The cycle embodies chemical looping combustion (CLC) and uses a Na based oxygen carrier. In operation, a stoichiometric excess of liquid Na is injected directly into the combustion chamber of a gas turbine cycle, where it is burnt in compressed O2 produced in an external air separation unit (ASU). The resulting combustion chamber exit stream consists of hot Na vapour, and this is expanded in a turbine. Liquid Na2O oxide is also generated in the combustion process, but this can be separated, readily, from the Na vapour and collects in a pool at the bottom of the reactor. To regenerate liquid Na from Na2O, and hence complete the chemical loop, a reduction reactor (the reducer) is fed with three streams: the hot Na2O from the oxidiser; the Na vapour (plus some entrained wetness) exiting a Na-turbine; and a stream of solid fuel, which is assumed to be pure carbon for simplicity. The sensible heat content of the liquid Na2O and latent and sensible heat of the Na vapour provide the heat necessary to drive the endothermic reduction reaction and ensure the reducer is externally adiabatic. The exit gas from the reducer consists of almost pure CO which can be used to generate by-product H2 using the water-gas shift reaction. A mass and energy balance of the system is conducted assuming reactions reach equilibrium. The analysis allows for losses associated with turbomachinery; heat exchangers are assumed to operate with a finite approach temperature; however, pressure losses in equipment and pipework are assumed negligible — a reasonable assumption for this type of analysis that will still yield meaningful data. The analysis confirms that the combustion chamber exit temperature is limited by both first and second law considerations to a value suitable for a practical gas turbine. The analysis also shows that the overall efficiency of the cycle, under optimum conditions and taking into account the work necessary to drive the ASU, can exceed 75%.

Fe-substituted Ba-hexaaluminates oxygen carrier for carbon dioxide capture by chemical looping combustion of methane

AIChE Journal ◽  
2015 ◽  
Vol 62 (3) ◽  
pp. 792-801 ◽  
Author(s):  
Ming Tian ◽  
Xiaodong Wang ◽  
Xin Liu ◽  
Aiqin Wang ◽  
Tao Zhang
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Capture ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping

Chemical Looping Combustion Using the Direct Combustion of Liquid Metal in a Gas Turbine Based Cycle

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Niall R. McGlashan ◽  
Peter R. N. Childs ◽  
Andrew L. Heyes
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Oxygen Carrier ◽  
Combustion Process ◽  
Combined Cycle ◽  
Air Separation ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Sensible Heat ◽  
Separation Unit

A combined cycle gas-turbine generating power and hydrogen is proposed and evaluated. The cycle embodies chemical looping combustion (CLC) and uses a Na based oxygen carrier. In operation, a stoichiometric excess of liquid Na is injected directly into the combustion chamber of a gas-turbine cycle, where it is burnt in compressed O2 produced in an external air separation unit (ASU). The resulting combustion chamber exit stream consists of hot Na vapor and this is expanded in a turbine. Liquid Na2O oxide is also generated in the combustion process but this can be separated, readily, from the Na vapor and collects in a pool at the bottom of the reactor. To regenerate liquid Na from Na2O, and hence complete the chemical loop, a reduction reactor (the reducer) is fed with three streams: the hot Na2O from the oxidizer, the Na vapor (plus some entrained wetness) exiting a Na-turbine, and a stream of solid fuel, which is assumed to be pure carbon for simplicity. The sensible heat content of the liquid Na2O and latent and sensible heat of the Na vapor provide the heat necessary to drive the endothermic reduction reaction and ensure the reducer is externally adiabatic. The exit gas from the reducer consists of almost pure CO, which can be used to generate byproduct H2 using the water-gas shift reaction. A mass and energy balance of the system is conducted assuming reactions reach equilibrium. The analysis allows for losses associated with turbomachinery; heat exchangers are assumed to operate with a finite approach temperature. However, pressure losses in equipment and pipework are assumed negligible—a reasonable assumption for this type of analysis that will still yield meaningful data. The analysis confirms that the combustion chamber exit temperature is limited by both first and second law considerations to a value suitable for a practical gas-turbine. The analysis also shows that the overall efficiency of the cycle, under optimum conditions and taking into account the work necessary to drive the ASU, can exceed 75%.

Techno-Economic Evaluation of Pressurized Oxy-Fuel Combustion Systems

2010 ◽  
Author(s):  
Jongsup Hong ◽  
Ahmed F. Ghoniem ◽  
Randall Field ◽  
Marco Gazzino
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Power Plants ◽  
Carbon Dioxide Capture ◽  
Fuel Combustion ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Air Separation ◽  
Separation Unit ◽  
Coal Price

Oxy-fuel combustion coal-fired power plants can achieve significant reduction in carbon dioxide emissions, but at the cost of lowering their efficiency. Research and development are conducted to reduce the efficiency penalty and to improve their reliability. High-pressure oxy-fuel combustion has been shown to improve the overall performance by recuperating more of the fuel enthalpy into the power cycle. In our previous papers, we demonstrated how pressurized oxy-fuel combustion indeed achieves higher net efficiency than that of conventional atmospheric oxy-fuel power cycles. The system utilizes a cryogenic air separation unit, a carbon dioxide purification/compression unit, and flue gas recirculation system, adding to its cost. In this study, we perform a techno-economic feasibility study of pressurized oxy-fuel combustion power systems. A number of reports and papers have been used to develop reliable models which can predict the costs of power plant components, its operation, and carbon dioxide capture specific systems, etc. We evaluate different metrics including capital investments, cost of electricity, and CO2 avoidance costs. Based on our cost analysis, we show that the pressurized oxy-fuel power system is an effective solution in comparison to other carbon dioxide capture technologies. The higher heat recovery displaces some of the regeneration components of the feedwater system. Moreover, pressurized operating conditions lead to reduction in the size of several other critical components. Sensitivity analysis with respect to important parameters such as coal price and plant capacity is performed. The analysis suggests a guideline to operate pressurized oxy-fuel combustion power plants in a more cost-effective way.

scholarly journals Modeling of the Chemical Looping Combustion of Hard Coal and Biomass Using Ilmenite as the Oxygen Carrier

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5394
Author(s):  
Anna Zylka ◽  
Jaroslaw Krzywanski ◽  
Tomasz Czakiert ◽  
Kamil Idziak ◽  
Marcin Sosnowski ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Oxygen Carrier ◽  
Experimental Tests ◽  
Chemical Looping Combustion ◽  
Hard Coal ◽  
Chemical Looping ◽  
Simulation Accuracy ◽  
Energy Technologies ◽  
Fuel Reactor ◽  
Relative Errors

This paper presents a 1.5D model of a fluidized bed chemical looping combustion (CLC) built with the use of a comprehensive simulator of fluidized and moving bed equipment (CeSFaMB) simulator. The model is capable of calculating the effect of gas velocity in the fuel reactor on the hydrodynamics of the fluidized bed and the kinetics of the CLC process. Mass of solids in re actors, solid circulating rates, particle residence time, and the number of particle cycles in the air and fuel reactor are considered within the study. Moreover, the presented model calculates essential emissions such as CO2, SOX, NOX, and O2. The model was successfully validated on experimental tests that were carried out on the Fluidized-Bed Chemical-Looping-Combustion of Solid-Fuels unit located at the Institute of Advanced Energy Technologies, Czestochowa University of Technology, Poland. The model’s validation showed that the maximum relative errors between simulations and experiment results do not exceed 10%. The CeSFaMB model is an optimum compromise among simulation accuracy, computational resources, and processing time.

scholarly journals Development of Multimode Gas Fired Combined Cycle Chemical-Looping Combustion Based Power Plant Lay-Outs

2021 ◽  
Author(s):  
Basavaraja Revappa Jayadevappa
Keyword(s):  
Carbon Dioxide ◽  
Power Plant ◽  
Natural Gas ◽  
Flue Gas ◽  
Power Plants ◽  
Carbon Dioxide Capture ◽  
Combined Cycle ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Operating Pressure

Abstract Operation of power plants in carbon dioxide capture and non-capture modes and energy penalty or energy utilization in such operations are of great significance. This work reports on two gas fired pressurized chemical-looping combustion power plant lay-outs with two inbuilt modes of flue gas exit namely, with carbon dioxide capture mode and second mode is letting flue gas (consists carbon dioxide and water) without capturing carbon dioxide. In the non-CCS mode, higher thermal efficiencies of 54.06% and 52.63% efficiencies are obtained with natural gas and syngas. In carbon capture mode, a net thermal efficiency of 52.13% is obtained with natural gas and 48.78% with syngas. The operating pressure of air reactor is taken to be 13 bar for realistic operational considerations and that of fuel reactor is 11.5 bar. Two power plant lay-outs developed based combined cycle CLC mode for natural gas and syngas fuels. A single lay-out is developed for two fuels with possible retrofit for dual fuel operation. The CLC Power plants can be operated with two modes of flue gas exit options and these operational options makes them higher thermal efficient power plants.

Coprecipitated, Copper-Based, Alumina-Stabilized Materials for Carbon Dioxide Capture by Chemical Looping Combustion

ChemSusChem ◽  
2012 ◽  
Vol 5 (8) ◽  
pp. 1610-1618 ◽  
Author(s):  
Qasim Imtiaz ◽  
Agnieszka Marta Kierzkowska ◽  
Christoph Rüdiger Müller
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Capture ◽  
Chemical Looping Combustion ◽  
Chemical Looping
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