| The environmental protection policy puts forward higher requirements for fuel oil quality,restricts the use of high octane gasoline components such as catalytic cracking and catalytic reforming and non-hydrocarbon antiknock agents in the gasoline pool.Alkylated oil with high octane,non-aromatics,olefin,benzene,oxygen,sulfur and isomeric alkanes as the main body becomes the ideal component of gasoline.C4 resource is a high quality raw material for alkylation oil production.As the main alkylation product,isooctane has a high octane number.With the increase of the scale of coal-to-olefin,the popularization of ethanol-gasoline,and the limitation of MTBE content in gasoline,the content of isobutylene in C4 resources increased obviously,which caused the quality fluctuation of alkylation products.This paper analyzes the adaptability of alkylation unit to carbon C4 and studies the feasible measures to improve the quality decline of alkylation products caused by the increase of isobutylene.In this paper,the equilibrium constant method is used to solve the thermodynamic equilibrium composition of the reaction system,and the ternary mixture design is created to analyze the adaptability of the alkylation device with temperature change of the system.The results show that the liquid phase alkylation reaction is an irreversible exothermic process in the range of-10?50?.The heat release increases with the increase of temperature,and the heat release of the product is slightly higher than that of the by-product.When isobutylene is involved in the alkylation reaction,the heat effect is the least,which is beneficial to the heat transfer and temperature control of the alkylation process.The equilibrium conversion of different butene alkylation reactions is more than 99.9%,and the equilibrium conversion of isobutylene alkylation is slightly lower than that of the other two alkenes.The selectivity of TMP with higher octane number decreased with increasing temperature,while the selectivity of DMH and MH increased with increasing temperature.Increasing the alkane-alkylene ratio and acid-hydrocarbon ratio are an effective means to reduce the adiabatic temperature rise and stabilize the reaction temperature.When the isobutylene is increased by 20%(volume fraction),the thermal effect of the system is reduced by 3.4%,and the required alkylene ratio and acid-hydrocarbon ratio are reduced by 3.8% and 4.5% to maintain the reaction temperature.The RGibbs reactor in Aspen Plus chemical process simulation software is used to simulate the thermodynamic equilibrium composition of light hydrocarbon,C8 alkane and C8 olefin generated from mixed butene alkylation by RK-Sove physical property method.Antoin equation and ideal mixture theory are combined to analyze the effects of temperature and pressure to regulate the reaction phase to maintain the steady-state operation of the device.Isobutane exist in C4 promotes alkylation,isomerization,fracture and disproportionation reaction,inhibition of butene composite reactions,butadiene promotes composite response,inhibits other reaction obviously,ensure isobutane adequate circulation to increase isobutane-alkylene ratio and remove impurity butadiene are necessary measures to deal with the quality fluctuation of alkylated products caused by the frequency change of C4 feedstock.Relative 1-butene,2-butene,the alkylation product selectivity is low and the octane number decreasing obviously with the temperature variation,mixture design is established to analyze the relationship between butene component,reaction temperature and RON.It can be appropriately compensate for lack of isobutene alkylation product octane number down,stable product quality by adjusting the reactor heat load,optimization of raw materials. |
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