Net zero carbon captive power generation using compressor inlet air cooling approach

Abstract

The study examines converting petroleum sector captive power plants to combined cycle power plant (CCPP) with CO₂ mitigation. The study used a novel approach to cool the compressor inlet air with vapour absorption refrigeration systems (VARS). VARS used steam bled by pass-out system from a steam turbine. The study selects the Rajasthan refinery captive power plant in India as a case study. The model predicts plant performance under different inlet conditions, factoring in local climate with amine-based CO₂ capture system. The study employed a thermodynamic model to analyse the effects of varying compressor inlet air temperature by using VARS with CO₂ emission mitigation. This study has shown that a CCPP integrated with VARS increases the gas turbine power output in the range of 0.42 MW to 5.74 MW as the compressor inlet temperature decreases from 40 °C to 15 °C. The combined power output increased by 4.69 MW at 15 °C and overall efficiency increased by 2.77 %, and maximum combined cycle efficiency reached 48.60 %, along with the capability to harvest condensed fresh water at a rate of 0.75 kg/s under ambient relative humidity of 30 % and 20 °C dew point temperature. When the plant is equipped with a CO₂ capture system for the range of inlet air temperatures, the efficiency decreases to a range of 34.20 % to 31.43 %. However, the plant significantly reduces its CO₂ emissions from 0.459 kg CO₂/kWh to 0.0645 kg CO₂/kWh i.e. comparable to renewable energy plants. Thus, the proposed system showcases its potential to contribute to a cleaner energy transition.