Energetic and Environmental Analysis of Partial Repowering of a Coal Fired Power Plant Through Upstream GT Integration and Employing Waste Heated Feed Water Heaters

Author(s):  
S. Samanta ◽  
S. Ghosh

This paper presents a theoretical study of partial repowering scheme for an existing 210MW coal fired power plant and reports predicted performance improvement obtainable from the repowering by using Cycle Tempo software. In this method old boiler is used as it is, only modifying its air heater and forced flow sections. Out of four operating coal mills, one mill is considered to be taken out. A new natural gas fired gas turbine (GT) block is considered to be integrated with the existing plant whose exhaust is fed to the existing boiler. The GT size is selected such that its exhaust provide heat input equivalent to the replaced coal mill. The burners associated with that coal mill are assumed to be modified to handle hot exhaust gas from the GT block. It is noticed that a substantial amount of energy is available in the flue gas, coming out from the boiler, after the air preheater which can partially meet the heat loads of feed water heaters. This helps in saving of intermediate pressure (IP) and low pressure (LP) bleed steam and consequent increase in the output of the steam cycle. The partial repowering results in nearly 40% increase in capacity of the plant (from 210MW to 284MW). It also results in substantial increase in overall efficiency of the repowered plant by 28%, and consequent decrease in plant heat rate by 22%. The specific CO2 emission of the plant decreases about 31% after repowering.

Author(s):  
H. A. Bazzini

Much of the steam-turbine based, power generating units all over the word are more than 30 years old now. Within a few years they will face the possibility of retirement from service and replacement. Nonetheless some of them are firm candidates for repowering, a technology able to improve plant efficiency, output and reliability at low costs. This paper summarizes a study performed to establish the feasibility to repower a 2 × 33 MW steam turbine power plant and the procedure followed until selection of the steam cycle more suitable to the project. The preferred solution is compared with direct replacement of the units by a new combined cycle. Various repowering options were reviewed to find “beat recovery” type repowering as the best solution. That well-known technology consists of replacing the steam generator by a gas turbine coupled to an HRSG, supplying steam to the existing steam turbine. Three “GT+HRSG+ST” arrangements were considered. Available gas turbine-generators — both industrial and aero-derivative type —, were surveyed for three power output ranges. Five “typical” gas turbine-generator classes were then selected. Steam flow raised at the HRSG, gross and net power generation, and heat exchanging surface area of the HRSG, were calculated for a broad range of usually applied, steam turbine throttle conditions. Both single pressure and double pressure steam cycles were considered, as well as supplemental fire and convenience of utilizing the existing feed water heaters. Balance of plant constraints were also reviewed. Estimates were developed for total investment, O&M costs, fuel expenses, and revenues. Results are shown through various graphics and tables. The route leading to the preferred solution is explained and a sensitivity analysis added to validate the selection. The preferred solution, consisting in a Class 130 gas turbine in arrangement 1–1–2, a dual-pressure HRSG and a steam cycle without feed-water heaters, win allow delivering 200 MW to the grid, with a heat rate of 7423 kJ/kW-hr. Investment was valued at $MM77.0, with an IRR of 15.3%. Those figures compare well with the option of installing a new GTCC unit: with a better heat rate but an investment valued at $MM97.5, its IRR will only be 12.4%.


Alloy Digest ◽  
1969 ◽  
Vol 18 (6) ◽  

Abstract Cupro Nickel, 30%-716 is a high strength copper-nickel-iron alloy for heat exchanger tubes in power plant feed water heaters, and also for oil refinery service. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, joining, and surface treatment. Filing Code: Cu-200. Producer or source: Anaconda American Brass Company.


2013 ◽  
Vol 34 (4) ◽  
pp. 199-214
Author(s):  
Mateusz Brzęczek ◽  
Łukasz Bartela

Abstract This paper presents the parameters of the reference oxy combustion block operating with supercritical steam parameters, equipped with an air separation unit and a carbon dioxide capture and compression installation. The possibility to recover the heat in the analyzed power plant is discussed. The decision variables and the thermodynamic functions for the optimization algorithm were identified. The principles of operation of genetic algorithm and methodology of conducted calculations are presented. The sensitivity analysis was performed for the best solutions to determine the effects of the selected variables on the power and efficiency of the unit. Optimization of the heat recovery from the air separation unit, flue gas condition and CO2 capture and compression installation using genetic algorithm was designed to replace the low-pressure section of the regenerative water heaters of steam cycle in analyzed unit. The result was to increase the power and efficiency of the entire power plant.


Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 19 ◽  
Author(s):  
Enhui Sun ◽  
Han Hu ◽  
Hangning Li ◽  
Chao Liu ◽  
Jinliang Xu

It is difficult to recover the residual heat from flue gas when supercritical carbon dioxide (S-CO2) cycle is used for a coal fired power plant, due to the higher CO2 temperature in tail flue and the limited air temperature in air preheater. The combined cycle is helpful for residual heat recovery. Thus, it is important to build an efficient bottom cycle. In this paper, we proposed a novel exergy destruction control strategy during residual heat recovery to equal and minimize the exergy destruction for different bottom cycles. Five bottom cycles are analyzed to identify their differences in thermal efficiencies (ηth,b), and the CO2 temperature entering the bottom cycle heater (T4b) etc. We show that the exergy destruction can be minimized by a suitable pinch temperature between flue gas and CO2 in the heater via adjusting T4b. Among the five bottom cycles, either the recompression cycle (RC) or the partial cooling cycle (PACC) exhibits good performance. The power generation efficiency is 47.04% when the vapor parameters of CO2 are 620/30 MPa, with the double-reheating-recompression cycle as the top cycle, and RC as the bottom cycle. Such efficiency is higher than that of the supercritical water cycle power plant.


Fuel ◽  
2020 ◽  
Vol 280 ◽  
pp. 118577 ◽  
Author(s):  
S.O. Oyedepo ◽  
B.A. Fakeye ◽  
B. Mabinuori ◽  
P.O. Babalola ◽  
R.O. Leramo ◽  
...  

Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
J. A. Becerra ◽  
A. Mun˜oz ◽  
T. Sa´nchez

In this work, a tool to predict the performance of fossil fuel steam power plants under variable operating conditions or under maintenance operations has been developed. This tool is based on the Spencer-Cotton-Cannon method for large steam turbine generator units. The tool has been validated by comparing the predicted results at different loads with real operating data of a 565 MW steam power plant, located in Southern Spain. The results obtained from the model show a good agreement with most of the power plant parameters. The simulation tool has been then used to predict the performance of a steam power plant in different operating conditions such as variable terminal temperature difference or drain cooler approach of the feed-water heaters, or under maintenance conditions like a feed-water heater out of service.


Data in Brief ◽  
2020 ◽  
Vol 32 ◽  
pp. 106086
Author(s):  
S.O. Oyedepo ◽  
O. Kilanko ◽  
M.A. Waheed ◽  
O.S.I. Fayomi ◽  
O.S. Ohunakin ◽  
...  

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