Potential for Reducing CO2 Emissions in the Operation of Subcritical Power Plants into Supercritical (original) (raw)
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PERFORMANCE ANALYSIS OF SUPERCRITICAL BOILER
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Coal fired power generation is switching over to supercritical (SC) and ultra supercritical (USC) plants which operate with steam on higher temperature and above critical pressure to produce power output at higher thermal efficiency. Due to involvement of high heat resistant material, manufacturing cost of the components of supercritical plants are increases, but due to higher efficiency its operating cost is low as compare to subcritical plants. An analysis has been made in the study to explore the possibilities of operating power plants with steam at higher temperature and pressure. Due to high efficiency of this plant 15 % lower co2 emission is achieved by high steam parameters as compare to subcritical plants. Analysis shows that for different operating condition of boilers and turbine, if there is an increment in the load of boiler and drop in the load of turbine higher efficiency is obtained. There are two parameters boiler maximum continuous rating (BMCR) and turbine maximum continuous rating (TMCR) are varied by increasing the value of steam flow rate of superheaters and reheaters. By increasing or decreasing these values we can find out which condition is best for power generation. A comparative study between subcritical and supercritical boilers and analysing the performance of boilers, Factor affecting efficiency of boilers has carried out with identification and analysis for improved working of supercritical plants
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This paper mainly studies the energy-saving potential of a 600 MW coal-fired supercritical power plant using the energy-loss analysis method. Main factors in the boiler and turbines such as the main steam temperature and pressure, the turbine cylinder efficiency, the condenser pressure and so on are taken as the variables to analyze the system's thermal and coal consumption rates. In addition, the real operation data at the loads of 75% and 50% are analyzed to trace the added thermal and coal consumptions. These results indicate the energy-saving direction for the system. The analyzing method can also be applied to other power generating systems to analyze the energy loss distributions.
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This article presents the performance analysis of a 700 MW future planned advanced ultra-supercritical (A-USC) coal-fired power plant fitted with post-combustion carbon capture and storage (CCS) technology. The reference A-USC unit without CCS achieves a net efficiency of 47.6% with CO2 emissions of 700 kgCO2/MWh. Relatively to subcritical units, the net efficiency of the A-USC is 8%-pts higher while CO2 emissions are 16.5% lower. For a CO2 removal rate of 90%, the net efficiency of the CCS integrated A-USC unit is 36.8%. The resulting net efficiency loss is 10.8%-pts and the electricity output penalty is 362.3 kWhel/tCO2 for present state CCS technology. The study continues with the assessment of interface quantities between the capture unit and the steam cycle affecting the performance of the A-USC. Improved CO2 absorbents could alleviate the net efficiency loss by 2–3%-pts, and enhanced CO2 compression strategies and advanced heat integration could further reduce the efficiency l...
International Journal of Design & Nature and Ecodynamics, 2022
This paper analyzes the 660 MW supercritical thermal power plant design data, operation data, and various improvement strategies of all significant auxiliary equipment at various plant load factors. The effects of the plant load factor, auxiliary equipment performance and multiple properties of coal on equipment performance are discussed here. It is observed that the operation of the supercritical thermal power plant, at the maximum continuous rating, reduces the specific auxiliary power from 5.95% at 65% Plant load factor to 4.76% at 100% Plant load factor. Hence, there is a reduction in auxiliary power of total equipment by 68.80 MU/year. Also, due to the reduction of auxiliary power, CO2 emissions reduce to 65,300 tonnes, SO2 emission reduces to 4.752 tonnes, and NOx emission reduces to 2.898 tonnes. This paper discusses and analyzes the optimization of the process, optimization of excess air, improving energy efficiency measures for individual equipment, and controlling furnace ingress. Analysis indicates the increase in plant capacity and reduction in the auxiliary power by 0.8-1.2% of gross energy generation and also a release of an additional power 7.85 MW/hour to the concerned grid.
PF-Fired Supercritical Boilers Operational Issues and Coal Quality Impacts
The use of super-critical (SC) steam conditions has been applied in recent Australian, European and Japanese coal fired power stations. For example, recent Australian units use conditions of 566°C and 25 MPa, Japanese units have used 600°C, 24.1 MPa and associated with 40% efficiency, and a European project aims to develop 700°C technology and 50% efficiency.
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This study evaluates and compared the performance of coal-fired power plants in ultra-supercritical (USC) versus integrated gasification combined cycle (IGCC). System performance in terms of environmental analysis. Base on the exhaust emissions than IGCC and USC in terms of SO2, CO2, CO, and H2S. The IGCC system is modeled and simulated with post-combustion capture and both of them used sub-bituminous coal from the Indramayu PLTU. The result display that with the same amount of raw materials (20 ton/h coal) the IGCC produce lower exhaust emissions than USC. IGCC produced 7.80 ton CO2-eq. / MWh and USC of 27.93 ton CO2-eq. / MWh. IGCC technology for the long term will be better than USC because it has produced greater electrical power with the amount of material the same coal standard and produces lower exhaust emissions.
International Journal of Mathematical, Engineering and Management Sciences
The comparative performance study is carried out for 500 MW Supercritical (SupC) Oxy-Coal Combustion (OCC) and Air-Coal Combustion (ACC) power plants with membrane-based CO2 capture at the fixed furnace temperature. The proposed configurations are modelled using a computer-based analysis software 'Cycle-Tempo' at different operating conditions, and the detailed thermodynamic study is done by considering Energy, Exergy, and Environmental (3-E) analysis. The result shows that the net energy and exergy efficiencies of ACC power plants with CO2 capture are about 35.07 % and 30.88 %, respectively, which are about 6.44 % and 5.77 % points, respectively higher than that of OCC power plant. Auxiliary power consumption of OCC based power plant is almost 1.97 times more than that of the ACC based plant due to huge energy utilization in the Air Separation Unit (ASU) of OCC plant which leads to performance reduction in OCC plant. However, environmental benefit of OCC based power plant i...
A concept of coal-fired power plant built around a supercritical CO 2 Brayton power cycle and 90% post-combustion CO 2 capture have been designed. The power cycle has been adapted to the coal-fired boiler thermal output, this boiler has been roughly designed in order to assess the power cycle pressure drop and its cost, an adapted CO 2 capture process has been designed and finally the overall heat integration of the power plant has been proposed. Due to the high complexity of such as plant, this paper does not intend to provide definitive evaluation of the concept but to explore its potential. A coal power plant with CO 2 power cycle without carbon capture could achieve a net efficiency of 50% (LHV) with a maximal temperature and pressure of 620 C and 300 bar, these performances has to be validated but the first results on pilot plant are encouraging. The CO 2 capture process use mono-ethanolamine as solvent and is equipped with vapor recompression systems in order to reduce the heat needed from the CO 2 cycle. It achieves around 2.2 GJ/t CO2 of specific boiler duty with 145 kWh/t CO2 of electrical auxiliary consumption including compression to 110 bar. The energetic evaluation of the overall power plant carried out highlights the promising potential of CO 2 supercritical cycle. A net power plant efficiency of 41.3% (LHV), with carbon capture and CO 2 compression to 110 bar, seem to be achievable with available or close-to-available equipment. A technical-economic evaluation of the designed power plant has been performed. It shows a levelized cost of electricity reduction of 15%, and a cost of avoided CO 2 reduction of 45%, without transport and storage, compared to a reference supercritical coal-fired power plant equipped with standard carbon capture process.
Energy and exergy analyses of a supercritical power plant
International Journal of Exergy, 2011
Energy and exergy efficiencies of a supercritical power plant have been studied in this paper. The effect of ambient weather condition was considered on the condenser pressure. It was shown that high ambient temperature has more adverse effect on the exergy efficiency than the energy efficiency. As ambient temperature increases, the exergy efficiency of the boiler, condenser, heaters and feed water pump decrease, while the exergy efficiency of the turbine improves slightly. The analysis showed that exergy efficiency of the supercritical boiler is considerably higher than the conventional boiler but it is still the main source of total irreversibility.
Clean Technologies and Environmental Policy, 2013
The present work has been undertaken for energetic and exergetic analysis of coal-fired supercritical thermal power plant and natural gas-fired combined cycle power plant. Comparative analysis has been conducted for the two contestant technologies. The key drivers of energetic and exergetic efficiencies have been studied for each of the major subsystem of two contestant technologies. Overall energetic and exergetic efficiency of coal-fired supercritical thermal power plant are found to be 43.48 and 42.89 %, respectively. Overall energetic and exergetic efficiency of natural gas-fired combined cycle power plant are 54.47 and 53.93 %, respectively. The major energetic power loss has been found in the condenser for coal-fired supercritical thermal power plant. On the other hand, the major energetic power loss has been found in both the condenser and heat recovery steam generator for gas-fired combined cycle thermal power plant. The exergetic analysis shows that boiler field is the main source of exergetic power loss in coal-fired supercritical thermal power plant and combustion chamber in the gas-fired combined cycle thermal power plant. It is concluded that natural gas-fired combined cycle power plant is better from energetic and exergetic efficiency point of view. These results will be useful to all involved in the improvement of the design of the existing and future power plants.