Cause And Countermeasure Analysis Of Reactor Sticking And Overtemperature Decomposition In LDPE/EVA Tubular Process

Basell's LUPOTECH TS high-pressure tubular process has been adopted by many domestic petrochemical companies to produce polyethylene products.For example:300 kt/a LDPE device of National Energy Group Shenhua Yulin Energy Chemical Co.,Ltd,and 300 kt/a LDPE/EVA device of Shaanxi Yanchang Coal Yulin Energy and Chemical Co.,Ltd.Although the tubular process is widely used,the reactor sticking problem is common in many companies.And it has become an important obstacle restricting the development of petrochemical companies.Therefore,analyzing the causes of reactor sticking and develop solutions are of great significance to improve the production capacity of the device.In this paper,the phenomenon of reactor sticking was discussed,and the influence and characteristics of the reactor sticking were analyzed.The reasons for reactor sticking and the preventive measures were also discussed.In the process of 2426K production of LDPE product,after the reactor is stuck to the wall,the peak-valley temperature of reaction zone 1 will rise to 260-270?,that of reaction zone 2 will rise to 260-275?,that of reaction zone 3 will rise to 270-280?,and that of reaction zone 4 will rise to 270-285?.This will lead to a sharp decline in the conversion of the polymerization reaction and a reduction in the plant load from 41-42T/H to 27-28T/H,reducing the production load of the plant by 33.3%.After eliminating the sticky wall of the reactor by process adjustment,the polymerization reaction of the device returned to normal.The peak and valley temperatures of reaction zone 1,reaction zone 2,reaction zone 3 and reaction zone 4 were maintained at 220-230?,220-235?,230-245? and 240-255?,respectively.The load of the device reaches 41-42t/H to achieve full load operation.This paper also studied the mechanism,phenomenon,cause analysis of polymerization reaction decomposition,as well as the prevention and treatment measures of decomposition.The decomposition of the polymerization reaction will bring great potential safety hazards to the operation of the device.The device is forced to stop to deal with the decomposed materials in the reactor,which is very difficult to deal with.The retention of the decomposed materials in the reactor will seriously affect the quality of subsequent products,and the product fog index rises from 5-6.5%to 8-9.5%,resulting in unqualified product quality.It is not difficult to find out that by analyzing the cause of reactor sticking and polymerization reaction decomposition.Adjusting the relevant process parameters of the device in time,it could effectively avoid the problems of the production decline and the unqualified product indicators caused by the sticky wall of the polymer,it can increase the output of the production plant by about 30 percent,and also avoid the unnecessary losses of enterprises.