Study On Selective Superposition Process Of C4 Olefins

With the rapid development of economic and people’s awareness of environmental protection,the demand of gasoline,with high octane,low vapor pressure,low sulfur nitrogen content,is getting higher and higher.Since 2017,China’s policy on ethanol gasoline for vehicles has been successively introduced.As a component of high-octane gasoline,MTBE will not be added to gasoline,resulting in a large number of MTBE devices facing production stoppage.The study found that the selective superposition process can use the raw materials of the original MTBE device,and the device can be slightly modified to maximize the use of existing resources to reduce losses.This paper uses microporous sulfonic acid resin as a catalyst to conduct a large number of experimental investigations on the selective superposition process of mixed C4 olefins.In this paper,the effects of temperature,space velocity,pressure and the acid amount on the selective superposition of mixed C4 olefins were systematically investigated.The acid exchange of DH-2 catalyst was carried out by sodium ion to adjust the acid amount of the catalyst.The effects of t-butanol(TBA)and ethanol inhibitors on the conversion of olefins and the distribution of superimposed products during C4 superposition were investigated.The ratio of alcohol to olefin ratio,reaction temperature and space velocity was optimized to obtain better process conditions for DIB-ETBE co-production process.The experimental results show that the decrease of temperature,the increase of space velocity and the decrease of acidity of catalyst will significantly reduce the conversion of 1-butene and increase the selectivity of C8=,but the conversion of isobutene will be greatly reduced and the yield of the target product cannot be improved;TBA was used as an inhibitor,when the amount of TBA was 0.5%mol/mol C4,the conversion of isobutylene and 1-butene decreased by 1.2%and 15.13%,respectively,and the selectivity of C8= was improved to some extent.The optimum conditions for the DIB-ETBE co-production process are that the reaction temperature is between 40 and 50℃,the mixing space velocity is 3 h-1,and the alcohol to olefin ratio is 0.1.Under the conditions,the isobutene conversion is 90.27%,the yield of the oligomerization product of 1-butene and isobutylene was reduced to 5.3%,and the yield of DIB was 48.72%.