Applied Research Of Pressure Energy And Cold Energy Recycled For Power Generation In Gas Pressure Regulating Process

For a long time,China's energy consumption structure is mainly on coal,which caused serious environmental pollution and ecological destruction.In order to improve the energy consumption structure,as clean energy,natural gas has been promoted greatly, more and more widely used in recently years.Our country's natural gas source is usually far away from cities which mainly use natural gas,the natural gas transportation mostly uses the high-pressure and long-distance pipeline.By times of stepping down from high-pressure to medium-pressure or low-pressure,natural gas can be transferred to the pipe network in cities to supply gas consumers.High-pressure gas contains a lot of pressure energy,through regulating pressure,the natural gas' s temperature drops largely,low temperature gas has much cold quantity.This paper proposed the pressure energy and the cold energy that produced in the process of regulating pressure can recycle to generate electricity,in order to recycle energy and achieve efficient utilization.This paper first uses exergy analysis model to analyze pressure exergy and cold exergy in the process of regulating natural gas' s pressure,calculating the potential of the pressure energy and cold energy in the city natural gas' s pressure regulation.The results showed that greater step-down gradient and higher environmental temperature,, more pressur exergy and cold exergy can be recycled.Energy recycle of pipelines has great potential.After analysis and calculation the energy recycle, proposed combined power generation system, recycle pressure energy and cold energy to generate electricity and then research. Analyzed on the combined power generation system energy efficiency under different gas supply parameters. Used black-box model to analysis of the equipments in the combined power generation system,the results showed that heat exchanger exergy loss very much, exergy efficiency is low, heat exchanger is one of the optimized direction in practical engineering.Analyzed the the influence factors on the system internal parameters,researches the relationship between outlet gas temperature with system energy efficiency,cycle workingmedium flow and expander inlet pressure with system energy efficiency.In the target of maximum system energy efficiency, the optimization working condition has been simulated. Combining with the practical characteristics of gas pressure regulating, several typical level regulating systems has been simulated. The whole system efficiency analysis shows that recycle pressure energy and cold energy to generate electricity has good application and implementation,providing reference for the energy recycle in the process of regulating pressure.