Optimization Of Shallow Cryogenic Distillation For Recycling Carbon Dioxide

As an important resource in modern life, CO2has been widely applied in manyfields of food processing, tobacco, carbonated beverage, electronics, metallurgy,welding, casting, petroleum, chemical, fire, and others. There are extensive resourcesfor production of carbon dioxide.Some examples: by-product of ammonia plant,by-product of ethanol production, petrochemical production (ethylene oxide,phosphate, acid neutralization), natural gas, natural gas processing, oil refineries,calcined limestone kiln gas recovery, CO2resources...99.7%of the effluent of the purification section of coal based methanol process(500000tons)(Rectisol Process) is CO2. It has been through the fine desulfurizationand shallow cryogenic distillation method combined recovery device for carbondioxide recovering.However, fine desulfurization and shallow cryogenic distillation for carbondioxide recovery device have some following defects: in the operation, CO2pressureoften fluctuates with a negativeeffect on carbon dioxide device operation, resulting inlow raw gas temperature, low desulfurization efficiency. In this paper, based on adetailed analysis of carbon dioxide device, the following effective measures havebeen taken to optimize the technology, improve the device operation stability, reducethe production consumption, and further improve the economic benefits:1) changethe new type of vent valve, to stabilize raw material gas pressure;2) the increase inraw gas preheater, improve the effect of desulfurization tower, to prolong the cycledesulfurizer;3) by using carbon dioxide gas cooler, reduces the carbon dioxide gastemperature, which improves drying tower adsorption efficiency, and prolongs theservice cycle of molecular sieve.4) the low pressure nitrogen instead of air is used asregeneration gas to reduce the production cost.