Regenerative Gas Turbine, Regeneration Effectiveness, Compression Ratio, Thermal Efficiency, Power, Ambient temperature.
In this work, comprehensive operational and conceptual design basics of the Regenerative Gas Turbine were studied and applied to the Khartoum North Thermal Power Station, Sudan, which has a total power of 187MW. The analysis and results of this work were executed using the Engineering Equation Solver.The results show that, the increasing the effectiveness of the regenerative cycle increased the thermal efficiency. However, there is a turning point of compressor inlet temperature, after which the further increase of temperature and regenerator effectiveness will lead to decline in the thermal efficiency of the cycle. At lower regeneration and moderate regenerator effectiveness, the increase in compression ratio leads to an increase in thermal efficiency of the cycle. At the highest values of regeneration effectiveness, the increase in compression ratios reduced the thermal efficiency of the cycle. The results revealed that regeneration is more effective at lower pressure ratios, ambient temperatures, and low minimum (compressor) to maximum (combustor) temperature ratios. An increase in regeneration effectiveness decreases the specific fuel consumption for lower and moderate compression ratios. At higher compression ratios, increasing regenerator effectiveness leads to an increase in the specific fuel consumption (SFC) of the cycle. At low and moderate compressor inlet temperature, increasing the regenerator effectiveness decreases fuel demand in the combustor, which reflects in decreasing the heat rate to the combustor especially at higher regenerative effectiveness (e=95%). As the effectiveness varies between 10-75%, the compressor inlet temperature varies from 200K to 350K and the regenerator exhaust temperature exhibited different profiles according to the conditions of inlet temperature. It was found that power curve declines smoothly due to the increase in irreversibility of regeneration cycle and remains high at higher turbine inlet temperatures. Compressor inlet temperatures between 100-330K increase the regeneration effectiveness varying between 10-95%, resulting a in different profile of the combustor inlet temperature. The mass flow rate of the fuel in the combustor decreases with increasing regeneration effectiveness at lower compressor inlet temperatures. At higher inlet temperatures, the fuel flow rate will gradually increase with the regeneration effectiveness due increasing irreversibilities of the regenerator. For a compression ratio of 15, the fuel mass flow rate reaches the lowest value of (6.30 kg/sec) at the lowest ambient temperature of 200 K and a regenerative effectiveness of 95%. The increase of the lower heating value (LHV) leads to a gradual increase in the thermal efficiency of the regenerative gas turbine (RGT), due to increasing cycle power and combustor capacity. The results concluded that the regeneration effectiveness is higher at low and moderate compressor inlet temperatures and compression ratios, through which, avoiding the regenerator’s irreversibility is possible.