The Process Plan Of LNG Cold Energy For Low Temperature Crush Rubber And System Optimization

LNG cold energy can be used in many aspects, such as air separation, low temperature grain crushing, power generation technology, water desalination, etc,but because LNG is a liquid mixture at low tempreture such as-162 ℃, at present the use of the energy exists some problems such as low energy efficiency.The LNG segmented model is applied in this article, proposing high grade power plus low grade crush design idea jointly using the LNG cold energy.The technological process uses HYSYS simulation software, and regards RKS equation as the whole system property equation, finally utilizes the T-H method and T-H-2 method as the evaluation standard of system.Designed two kinds of technological process. In sole circulation medium plus secondary power generation process,70% of the cold exergy is used for Rankine cycle power generation, and 30% of the cold exergy is utilized for cryogenic grinding powder part.Furthermore,the exergy loss of organic mixed circulation medium plus single power generation process decreased by 9.8% comparing with sole circulation medium plus secondary power generation process.In addition, the simulation results show that when the the mass flow rate is 145.3 kg/h, the average efficiency of each main equipment can reach maximum 79.8%.According to the sole circulation medium plus secondary power generation process and the organic mixed circulation medium plus single power generation process,the article regards the maximum efficiency of the whole system as the evaluation standard of system. When the pinch point temperature is respectively 5℃.15℃.25℃, the article selects the best circulation medium and the optimal ratio of medium which make the system efficiency reach the maximum.In sole circulation medium plus secondary power generation process, when the pinch point temperature is 25 ℃, the primary power generation cycle working medium is R290 and the secondary power generation cycle working medium is R50; when the pinch point temperature is 15 ℃, the primary power generation cycle working medium is R170 and the secondary power cycle working medium choose is R50; when the pinch point temperature is 5 ℃, the primary power generation cycle working medium is R14 and the secondary power cycle working medium is R170.In organic mixed circulation medium plus single power generation process, when the pinch point temperature is 20 ℃, the best working medium mixed ratio is 63% R170+63% R290; when the pinch point temperature is 15 ℃, the best working medium mixed ratio is 31% R50+69% R170, which is the exergy efficiency is 17.8%; when the pinch point temperature is 5 ℃, the best working medium mixed ratio is 87% R50+13% R170, which is the exergy efficiency of 22.3%.