Improving Coal-Fired Power Plant Performance and Operating Flexibility Today

Author(s):  
Heinz Termuehlen

Since 50% of the electric power in the US is generated by pulverized-coal-fired power plants and 95% of the US fossil fuel reserves are coal, immediate action should be taken to improve coal-fired power plant performance. The DOE has started a program to develop most efficient coal-fired power plants with the goal to reach 60% net power plant efficiency. Present coal-fired power plants are mainly designed and built more than 30 years ago with a net power plant efficiency of about 32%. We should not wait for a general application of a future technology with the potential of reaching the 60% net efficiency level of coal-fired power plants. We must take action today and build more advanced pulverized-coal-fired power plants based on a technology, which has already gained operating experience and is commercially available. This paper shows how such power plants can be built as new units or as units replacing outdated units. A power plant net efficiency of 45% can be achieved even with highly effective emission reduction systems already included. The 40% lower specific coal consumption of these plants over present units reduces also the CO2 discharge by the same magnitude. Coal-fired power plants can also be designed for proving high operating flexibility. They can support the grid system in case of grid disturbances and can also stay at idle operation after full-load rejections for immediate reloading. Therefore, blackouts can be avoided. This paper provides detailed information on how to build such advanced pulverized-coal-fired power plants.

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Rajive Ganguli ◽  
Sukumar Bandopadhyay

The impact of particle size distribution (PSD) of pulverized, low rank high volatile content Alaska coal on combustion related power plant performance was studied in a series of field scale tests. Performance was gauged through efficiency (ratio of megawatt generated to energy consumed as coal), emissions (SO2,NOx, CO), and carbon content of ash (fly ash and bottom ash). The study revealed that the tested coal could be burned at a grind as coarse as 50% passing 76 microns, with no deleterious impact on power generation and emissions. The PSD’s tested in this study were in the range of 41 to 81 percent passing 76 microns. There was negligible correlation between PSD and the followings factors: efficiency, SO2,NOx, and CO. Additionally, two tests where stack mercury (Hg) data was collected, did not demonstrate any real difference in Hg emissions with PSD. The results from the field tests positively impacts pulverized coal power plants that burn low rank high volatile content coals (such as Powder River Basin coal). These plants can potentially reduce in-plant load by grinding the coal less (without impacting plant performance on emissions and efficiency) and thereby, increasing their marketability.


Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1681
Author(s):  
Dong-Jin Cho ◽  
Eul-Bum Lee ◽  
Jae-Min Cho ◽  
Douglas Alleman

In this study, an advanced-ultra super critical (A-USC) simulation model was developed using the Performance Evaluation of power system efficiencies (PEPSE) software and data collected from a 500 MW ultra-supercritical (USC) coal-fired power plant in South Korea. Using the operational USC and a typical A-USC power plant steam conditions, the model analyzed the impacts of adding an additional feedwater heater (FWH) and reheater to the baseline single reheater (SR) and 8 FWH case. Through the process of introducing reheat and/or regenerative cycles, the authors found: (1) A-USC steam conditions offers an approximate 4% power plant efficiency increase in comparison to the baseline USC steam conditions and; (2) power plant efficiencies increase approximately 1.5% when a 9th FWH and double reheater are added, however; (3) this also results in an approximate 64 °C increase in the superheating of extraction stream. This excessive rise in the superheating of extraction steam was found to cause overall energy loss, reducing the overall efficiency of the power plant. Therefore, it was surmised that if the increase in the superheat degree of extraction steam from the improved steam cycle, which can effectively reduce, the efficiency of the power plant could be further improved. To determine the efficiency variations based on the reduction of the superheat degree of extraction steam, the authors applied a regenerative turbine (RT) to the model. Introducing the RT to the A-USC DR and 9 FWH was found to decrease from the average extraction steam temperature from 221 °C to 108 °C and result in an increase in power plant efficiency of approximately 0.3% to 49.5%. An economic analysis was also performed to assess the fiscal feasibility of adding an RT. Assuming the initial investment to be USD 1409 million, implementing an RT equated to a net present value increase of approximately USD 33 million as compared to that of similar life (30 years of durability) expectancy of A-USC without using an RT. The findings of this study have the potential to improve South Korea’s energy policy, reducing the superheat degree of extraction steam that rises excessively during A-USC steam condition optimization. While this study is focused on South Korea, said findings are also generalizable to worldwide energy policies, serving as an effective method to not only increase system efficiencies, but enhance the economic feasibility as well.


Author(s):  
Shane E. Powers ◽  
William C. Wood

With the renewed interest in the construction of coal-fired power plants in the United States, there has also been an increased interest in the methodology used to calculate/determine the overall performance of a coal fired power plant. This methodology is detailed in the ASME PTC 46 (1996) Code, which provides an excellent framework for determining the power output and heat rate of coal fired power plants. Unfortunately, the power industry has been slow to adopt this methodology, in part because of the lack of some details in the Code regarding the planning needed to design a performance test program for the determination of coal fired power plant performance. This paper will expand on the ASME PTC 46 (1996) Code by discussing key concepts that need to be addressed when planning an overall plant performance test of a coal fired power plant. The most difficult aspect of calculating coal fired power plant performance is integrating the calculation of boiler performance with the calculation of turbine cycle performance and other balance of plant aspects. If proper planning of the performance test is not performed, the integration of boiler and turbine data will result in a test result that does not accurately reflect the true performance of the overall plant. This planning must start very early in the development of the test program, and be implemented in all stages of the test program design. This paper will address the necessary planning of the test program, including: • Determination of Actual Plant Performance. • Selection of a Test Goal. • Development of the Basic Correction Algorithm. • Designing a Plant Model. • Development of Correction Curves. • Operation of the Power Plant during the Test. All nomenclature in this paper utilizes the ASME PTC 46 definitions for the calculation and correction of plant performance.


Author(s):  
W. J. Thayer ◽  
R. T. Taussig

Applications of energy exchangers, a type of gasdynamic wave machine, were evaluated in power plants fired by pressurized, fluidized bed combustors (PFBCs). Comparative analyses of overall power plant efficiency indicate that the use of energy exchangers as hot gas expanders may provide a 0.5 to 1.5 efficiency point increase relative to gas turbines. In addition, the unique operating characteristics of these machines are expected to reduce rotating component wear by a factor of 50 to 300 relative to conventional gas turbines operating in the particulate laden PFBC effluent stream.


Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa

In the Ecuadorian electrical market, several sugar plants, which significantly participate in the local electricity market, are producing their own energy and commercializing the surplus to the electrical market. This study evaluates the integral use of the sugar cane bagasse for productive process on a Cogeneration Power Plant in an Ecuadorian Sugar Company [8]. The electrical generation based on biomass requires a great initial investment. The cost is around US$ 800/kW installed, twice the US$ 400/kW initial investment of conventional thermoelectric power plant and almost equal to the US$ 1,000/kW initial cost of hydroelectric power plant [5]. A thermoeconomic study was carried out on the production of electricity and the sales of the surplus of 27 MWe average produced by the power plant. An operational analysis was made using instantaneous values from the estimated curves of demand and generation of electricity. From the results, it was concluded that the generated electricity costs are 0.0443 US$/kWh, while the costs of the electricity from Fossil Power Plants (burning fuel oil, diesel fuel and natural gas) are in the range 0.03–0.15 US$/kWh and from Hydroelectric Plants are about 0.02 US$/kWh. Cogeneration power plants burning sugar cane bagasse could contribute to the mitigation of climatic change. This specific case study shows the reduction of the prospective emissions of greenhouse gases, around 55,188 ton of CO2 equivalent yearly for this cogeneration power plant.


2017 ◽  
Vol 1 (3) ◽  
pp. 49-53
Author(s):  
A Berger ◽  
◽  
A Lebrun ◽  
S Khan ◽  
Q Masson-Pilet ◽  
...  

2013 ◽  
Vol 56 (2) ◽  
pp. 179-184 ◽  
Author(s):  
V. M. Gureev ◽  
E. B. Mats ◽  
V. N. Ivanova ◽  
M. V. Gureev ◽  
D. A. Malyshkin ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document