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.

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.

Evaluation of the Effect of Firing Temperature, Cycle, Engine Configuration, Components, and Bottoming Cycle on the Overall Thermal Efficiency of an Indirectly Coal-Fired Gas Turbine Based Power Plant

2006 ◽  
Author(s):  
Richard P. Johnston
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Turbine Engine ◽  
Combined Cycle Plant ◽  
Plant Power

Potential LHV performance of an indirect coal-fired gas turbine-based combined cycle plant is explored and compared to the typical LHV 35–38 % thermal efficiencies achievable with current coal-fired Rankine Cycle power plants. Plant performance with a baseline synchronous speed, single spool 25:1 pressure ratio gas turbine with a Rankine bottoming cycle was developed. A coal-fired High Temperature Advanced Furnace (HITAF) supplying 2000° F. (1093° C.) hot pressurized air for the gas turbine was modeled for the heat source. The HITAF concept along with coal gas for supplemental heating, are two important parts of the clean coal technology program for power plants. [1,2] From this baseline power plant arrangement, different gas turbine engine configurations with two pressure ratios are evaluated. These variations include a dual spool concentric shaft gas turbine, dual spool non-concentric shaft arrangement, intercooler, liquid metal loop re-heater, free power turbine (FPT) and post HITAF duct burner (DB). A dual pressure Heat Recovery Steam Generator (HRSG) with varying steam pressures to fit conditions is used for each engine. A novel steam generating method employing flash tank technology is applied when a water-cooled intercooler is incorporated. A halogenated hydrocarbon working fluid is also evaluated for lower temperature sub-bottoming Rankine cycle equipment. Current technology industrial gas turbine component performance levels are applied to these various engines to produce a range of LHV gross gas turbine thermal efficiency estimates. These estimates range from the lower thirties to over forty percent. Overall LHV combined cycle plant gross thermal efficiencies range from nearly forty to over fifty percent. All arrangements studied would produce significant improvements in thermal efficiency compared to current coal-fired Rankine cycle power plants. Regenerative inter-cooling, free power turbines, and dual-spool non-concentric shaft gas turbine arrangements coupled with post-HITAF duct burners produced the highest gas turbine engine and plant efficiency results. These advanced engine configurations should also produce operational benefits such as easier starting and much improved part power efficiency over the baseline engine arrangement. An inter-turbine liquid metal re-heat loop reduced engine thermal efficiency but did increase plant power output and efficiency for the example studied. Use of halogenated hydrocarbons as a working fluid would add to plant power output, but at the cost of significant additional plant equipment.

A Transcritical CO2 Rankine Cycle With LNG Cold Energy Utilization and Liquefaction of CO2 in Gas Turbine Emission

2008 ◽  
Author(s):  
Meibin Huang ◽  
Wensheng Lin ◽  
Hongming He ◽  
Anzhong Gu
Keyword(s):  
Gas Turbine ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
Large Temperature ◽  
Specific Work ◽  
Environment Friendly ◽  
Cold Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

A novel transcritical Rankine cycle is presented in this paper. This cycle adopts CO2 as its working fluid, with exhaust from a gas turbine as its heat source and LNG as its cold sink. With CO2 working transcritically, large temperature difference for the Rankine cycle is realized. Moreover, the CO2 in the gas turbine exhaust is further cooled and liquefied by LNG after transferring heat to the Rankine cycle. In this way, not only the cold energy is utilized, but also a large part of the CO2 from burning of the vaporized LNG is recovered. In this paper, the system performance of this transcritical cycle is calculated. The influences of the highest cycle temperature and pressure to system specific work, exergy efficiency and liquefied CO2 mass flow rate are analyzed. The exergy loss in each of the heat exchangers is also discussed. It turns out that this kind of CO2 cycle is energy-conservative and environment-friendly.

scholarly journals New Mobile Gas Turbine with a Wide Range of Applications

2018 ◽  
Vol 140 (03) ◽  
pp. S54-S55
Author(s):  
Uwe Schütz
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Large Power ◽  
Power Stations ◽  
Wide Range ◽  
Term Basis

This article describes features and advantages of new mobile gas turbine with a wide range of applications. The market for mobile gas turbines is continuously growing. Mobile units are also an ideal choice when it comes to making large power capacities available on a short-term basis, for example, for major events, prolonged downtimes at other power stations, or power-intensive applications such as mining or shale gas extraction. If the electricity requirements exceed the level that can normally be demanded of a mobile application, an SGT-A45 installation can be modified to form a combined-cycle power plant to further improve its efficiency. In remote locations, this can be achieved using an Organic Rankine Cycle (ORC), to eliminate the need for water and water treatment systems, and to optimize energy recovery from the SGT-A45 off-gas stream at a relatively low temperature. The use of a direct heat exchanger, in which the ORC working fluid is evaporated by the off-gas stream from the gas turbine, can boost the system’s output capacity by more than 20 percent.

scholarly journals Comparative analysis of the Allam cycle and the cycle of compressorless combined cycle gas turbine unit

2020 ◽  
Vol 209 ◽  
pp. 03023
Author(s):  
Mikhail Sinkevich ◽  
Anatoliy Kosoy ◽  
Oleg Popel
Keyword(s):  
Comparative Analysis ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Thermal Power ◽  
District Heating ◽  
Combined Cycle ◽  
Working Fluid ◽  
District Heating System ◽  
Wide Range

Nowadays, alternative thermodynamic cycles are actively studied. They allow to remove CO2, formed as a result of fuel combustion, from a cycle without significant energy costs. Calculations have shown that such cycles may meet or exceed the most advanced power plants in terms of heat efficiency. The Allam cycle is recognized as one of the best alternative cycles for the production of electricity. Nevertheless, a cycle of compressorless combined cycle gas turbine (CCGT) unit is seemed more promising for cogeneration of electricity and heat. A comparative analysis of the thermal efficiency of these two cycles was performed. Particular attention was paid to ensuring equal conditions for comparison. The cycle of compressorless CCGT unit was as close as possible to the Allam cycle due to the choice of parameters. The processes, in which the difference remained, were analysed. Thereafter, an analysis of how close the parameters, adopted for comparison, to optimal for the compressorless CCGT unit cycle was made. This analysis showed that these two cycles are quite close only for the production of electricity. The Allam cycle has some superiority but not indisputable. However, if cogeneration of electricity and heat is considered, the thermal efficiency of the cycle of compressorless CCGT unit will be significantly higher. Since it allows to independently regulate a number of parameters, on which the electric power, the ratio of electric and thermal power, the temperature of a working fluid at the turbine inlet depend. Thus, the optimal parameters of the thermodynamic cycle can be obtained in a wide range of operating modes of the unit with different ratios of thermal and eclectic powers. Therefore, the compressorless CCGT unit can significantly surpass the best steam turbine and combined cycle gas turbine plants in district heating system in terms of thermal efficiency.

Electrical Power Generation: Fossil Fuels

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Steam Temperature

Nearly all electrical power is generated by rotating a coil in a magnetic field. In most cases, the coil is turned by a steam turbine operating according to the Rankine cycle. Water is boiled and heated to make high-pressure steam, which drives the turbine. The thermal efficiency is about 30–35%, and is limited by the highest steam temperature tolerated by the turbine blades. Alternatively, a gas turbine operating according to the Brayton cycle can be used. Much higher turbine inlet temperatures are possible, and the thermal efficiency is higher, typically 40%. Combined cycle generation, in which the hot exhaust from a gas turbine drives a Rankine cycle, can achieve thermal efficiencies of almost 60%. Substitution of coal-fired by combined cycle natural gas power plants can result in significant reductions in CO2 emissions.

A Transcritical CO2 Rankine Cycle With LNG Cold Energy Utilization and Liquefaction of CO2 in Gas Turbine Exhaust

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Wensheng Lin ◽  
Meibin Huang ◽  
Hongming He ◽  
Anzhong Gu
Keyword(s):  
Gas Turbine ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
Large Temperature ◽  
Specific Work ◽  
Environment Friendly ◽  
Cold Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

A novel transcritical Rankine cycle is presented in this paper. This cycle adopts CO2 as its working fluid with exhaust from a gas turbine as its heat source and liquefied natural gas (LNG) as its cold sink. With CO2 working transcritically, large temperature difference for the Rankine cycle is realized. Moreover, the CO2 in the gas turbine exhaust is further cooled and liquefied by LNG after transferring heat to the Rankine cycle. In this way, not only is the cold energy utilized but also a large part of the CO2 is recovered from burning of the vaporized LNG. In this paper, the system performance of this transcritical cycle is calculated. The influences of the highest cycle temperature and pressure to system specific work, exergy efficiency, and liquefied CO2 mass flow rate are analyzed. The exergy loss in each of the heat exchangers is also discussed. It turns out that this kind of CO2 cycle is energy-conservative and environment-friendly.

Analysis of a Combined Cycle Plant Using a Small Particle Receiver to Drive a Primary Brayton Cycle

2015 ◽  
Author(s):  
Matthew Miguel Virgen ◽  
Fletcher Miller
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Small Particle ◽  
Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Efficiency Gains ◽  
Steam Cycle

All current commercial CSP plants operate at relatively low thermodynamic efficiency due to lower temperatures than similar conventional plants and due to the fact that they all employ Rankine conversion cycles. We present here an investigation on the effects of adding a bottoming steam power cycle to a hybrid CSP plant based on a Small Particle Heat Exchange Receiver (SPHER) driving a gas turbine as the primary cycle. Due to the high operating temperature of the SPHER being considered (over 1000 Celsius), the exhaust air from the primary Brayton cycle still contains a tremendous amount of exergy. While in the previous analysis this fluid was only used in a recuperator to preheat the Brayton working fluid, the current analysis explores the potential power and efficiency gains from instead directing the exhaust fluid through a heat exchanger to power a Rankine steam cycle. Not only do we expect the efficiency of this model to be competitive with conventional power plants, but the water consumption per kilowatt-hour will also be reduced by nearly two thirds as compared to most existing concentrating solar thermal power plants as a benefit of having air as the primary working fluid, which eliminates the condensation step present in Rankine-cycle systems. Coupling a new steam cycle model with the gas-turbine CSP model previously developed at SDSU, a wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP combined cycle gas turbine (CCGT) plant. Due to the generalized nature of the bottoming cycle modeling, and the varying nature of solar power, special consideration had to be given to the behavior of the heat exchanger and Rankine cycle in off-design scenarios. The trade-offs of removing the recuperator for preheating the primary fluid are compared to potential overall power and efficiency gains in the combined cycle case.

Thermodynamic Design Point Study of a Semi-Closed Recuperated Intercooled Gas Turbine Combined With a Rankine Bottoming Cycle

1996 ◽  
Author(s):  
Todd S. Nemec ◽  
William E. Lear
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Mechanical Design ◽  
Rankine Cycle ◽  
System Size ◽  
Combined Cycle ◽  
Specific Power ◽  
Design Point ◽  
Recirculation Flow ◽  
Design Variables

A design point study of a semi-closed recuperated intercooled gas turbine combined with a closed, unfired, Rankine cycle is presented to demonstrate the overall thermodynamic design and efficiency tradeoffs for this type of cycle. Through its semi-closed design, having control over combustor equivalence ratio and recirculation flow exit pressure, this cycle provides improvements in emissions, specific power (net system power output divided by gas turbine inlet airflow), part power thermal efficiency, and overall system size relative to a combined cycle with an open cycle gas turbine. The relationship of design variables to cycle and component selection is discussed. Interface heat exchanger configuration, along with bottoming cycle choices of regeneration, feedwater heating, and fluid (H2O or DOWTHERM®A) are evaluated to determine their effects on mechanical design and thermal efficiency.

MCFC-GT Hybrid System Aiming at 70% Thermal Efficiency

2006 ◽  
Author(s):  
Eiichi Koda ◽  
Toru Takahashi
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Cell Voltage ◽  
Combined Cycle ◽  
Efficiency Improvement ◽  
Class System ◽  
Exhaust Heat ◽  
Calculation Results ◽  
Gas Turbine Exhaust ◽  
Co2 Recovery

The thermal efficiency improvement of fossil power generation is important to reduce both CO2 emission and power generating cost. To date, 60% (LHV) has been achieved with ACC (Advanced Combined Cycle) and a calculation result of 70% (LHV) or more has been reported for SOFC-GT hybrid. Then, we examined the thermal efficiency improvement considering the features of the gas turbine and the fuel cell, and designed the epoch-making cycle. By markedly improving the single-cell voltage of MCFC using oxygen as an oxidant, and having adopted a semiclosed cycle configuration in which gas turbine exhaust heat is effectively used almost completely, this cycle not only enables us to obtain an ultrahigh efficiency, but also can facilitate CO2 recovery. First, the thermal efficiency of a 300MW-class power plant using this cycle was examined, and it was confirmed that a net efficiency of 70% (HHV) or more was possible. Then, a 1MW-class system that can be realized in the near future is examined. As a result, it has been understood that it is promising as a small power supply, too. In this paper, the concept and basic configuration of this cycle were explained, and the detailed configuration and the thermal efficiency calculation results for both the 300MW-class system and the 1MW-class system are described.

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