Integrated and Cost-effective Design Utilizes LNG Cryogenic Energy for Power Generation
|School||South China University of Technology|
|Keywords||LNG Cold energy Pressure energy Generate electricity|
And pressure of the liquefied natural gas (LNG) is a temperature as low as -160.0 ℃ liquid supplied to downstream users usually use sea water to be vaporized and heated to above 0 ℃, a large number of cold taken away by the sea, causing a very large energy waste and environmental pollution. Take full advantage of the cold energy of LNG high-quality, energy conservation will have important theoretical and practical significance. LNG cold energy recovery and power generation applications more, but less efficient, and generally no higher than 30%. To solve this problem, the use of process simulation technology of LNG cold energy co-generation process simulation, analysis of LNG temperature, pressure, composition and turbine inlet temperature and refrigerant factors such as the impact of the system generating capacity, summed constrained systems The key factor of the power generation efficiency of propane and natural gas, the working fluid into the turbine, the temperature and the type of refrigerant. The proposed system thermal integration for the former, the use of low temperature waste heat process heating turbine working fluid imports; single refrigerant for the latter to get the best overall performance of the propane mixed refrigerant should adopt the the Kalina cycle alternative Rankine cycle conclusion. Apply research findings to the southeast coast of 3 million tons / year scale LNG terminal, by improving related processes to achieve integrated optimization process using two programs, the first option first implementation of process waste heat systems and the cold energy generation systems integration and optimized use of waste heat to heat the turbine inlet working fluid, increase total generating capacity of 2558 kW direct expansion acting thermal efficiency of 52.1% and 22.6%, natural gas and propane; then use the propane refrigeration 8 ℃ ice water 700t / h, respectively do the cooling compressor machine and receive stations operating room empty cold source, saving sea water amount of 3872 t / h, to save refrigeration power consumption 1124kW; compared to the original process, the system fire with the efficiency increased by 38%, creating effective 30,920,000 yuan / year; The second program is through the the Kalina cycle of C3H8-CF4 mixed refrigerant alternative Rankine cycle and low temperature waste heat to heat the working fluid of the gas turbine, LNG cold energy utilization is increased. Total consumption of the Kalina cycle levels improved turbine expanding power of 6933 kW, compared to the original process 3121kW, 122%; hydraulic turbine cycle working fluid acting as power generation capacity of 388 kW, the pump consumption power of 312 kW, the work is done by the system hydraulic turbine direct drive pump, thus to decrease the power consumption of the pump, to improve the energy utilization efficiency of the whole system purposes.