A novel solar assisted Kalina cycle system for waste heat utilization in thermal power plants

Abstract

In the conventional coal power plants, substantial amount of energy loss takes place through condenser, fluegas and coal mills rejection. Separate studies based on these waste heat resources with single Kalina Cycle System (KCS) in each case shows improvement in plant efficiency with additional power generation but the present study shows the combined waste heat utilization of condenser, fluegas and coal mill rejection in a 500MW e subcritical (SubC) coalfired thermal power plant using single solar assisted KCS. The modified configuration reduces the system complexity, space requirement and irreversibility by using less number of equipments. The system is thermodynamically modelled by MS-Excel macros for analysing the system performance at different conditions. The study shows that an additional electricity generation of about 10 738.42 kW increases the plant net energy and exergy efficiencies by about 0.852% and 0.761% points, respectively resulting in reduction of CO 2 emission by about 8.78 tons per hour at 55 K degree of solar heating. About 55.75 K and 7.20 K are the optimum Log Mean Temperature Difference (LMTD) values of the evaporator and steam condenser, respectively that yields the maximum net energy output economically at 12.60 bar operating pressure. Effect of solar energy variation on system performance is also carried out by varying the degree of solar heating. Economic analysis of the proposed system is also performed by considering 25 years of equipment life and a loan interest of about 14%. The cost of electricity and simple payback period (SPP) of solar assisted KCS are about Rs. 0.83/kWh and 1.19 years, respectively, at 55 K degree of solar heating (optimum). The study further shows that the levelized cost of excess electricity generation by solar heater is lower than the standalone solar thermal power plant by about 53.78%.

A novel calcium looping–integrated NGCC power plant configuration for carbon capture and utilization—Comprehensive performance analysis

“…3 This indicates that the renewable energy sources being the best alternative in overcoming the problem of GHG emissions are not competent to completely eliminate the utilization of conventional sources of energy, particularly natural gas. 4 Various energy integration strategies have also been developed in recent times both for coal fired power plants [5][6][7] and NGCC power plants [8][9][10] with renewable energy sources. The integration of renewables with the conventional power plants reduces the CO 2 emission per unit power generation.…”