Solution polymerization process
Industrialization was realized in the early 1960s. After continuous improvement and perfection, the technology has matured and been used by many newly built devices. It is the dominant technology in industrial production, accounting for about 77.6% of the total production capacity of FPR.
This process is a homogeneous reaction in a solvent that can dissolve the product, monomer and catalyst system. Usually, linear alkanes such as n-hexane are used as solvents, and V-A 1 catalyst system is adopted. The polymerization temperature is 30 ~ 50C, the polymerization pressure is 0.4 ~ 0.8 MPa, and the mass fraction of polymer in the reaction product is generally 8% ~ 10%. The technological process basically consists of raw material preparation, chemical preparation, polymerization, catalyst removal, monomer and solvent recovery and refining, coagulation, drying and polymerization.
Packaging and other processes, but because each company has its own patented technology in a certain part or control, it has its own unique process realization method. The representative companies are DSM, Exxon, uniroya 1, DuPont, Mitsui Petrochemical Company of Japan and JSR Company. The most typical one is DSM company, which is not only the largest EPR producer in the world, but also four plants in the Netherlands, the United States, Japan and Brazil all adopt solution polymerization process, accounting for 1/4 of the total production capacity of EPR by solution polymerization process in the world. Take this company as an example.
DSM takes hexane as the solvent, ethylidene norbornene (ENB) or dicyclopentadiene (DCPD) as the third monomer, hydrogen as the molecular weight regulator, and VOCL3- 1/2Al2O3 as the catalyst. In addition, in order to improve the activity of the catalyst and reduce its dosage, an accelerator was added. The proportion and dosage of catalyst, pretreatment method and accelerator type are the proprietary technology of DSM company. The reaction materials are precooled to 500℃, and one kettle or two kettles are operated in series according to the production brand. gather
The kettle has a volume of about 6m3. The polymerization conditions are as follows: the temperature is below 65℃ and the pressure is below 2. 5 MPa, and the reaction heat is used for adiabatic heating of the reactor. Under the action of alkaline vanadium removal agent and hot water, the residual vanadium catalyst in polymer glue solution enters the water phase and is completely removed through two phase inversion processes. Unreacted monomer is recovered and recycled by secondary decompression flash evaporation. At this time, why bother about bread crumbs? Love? Do you want to stop climbing in Tuanping? f？ Do you write pocket ants? ⒈? ┖ What's the matter?
The skimmed liquid is sent to two coagulation kettles in series for coagulation, and the remaining hexane solvent is further distilled and recovered. JC colloidal slurry enters the drying system after dehydration, and then is packaged into blocks or powders. The waste hot air containing ENB is sent to the incinerator for incineration, and the vanadium-containing sewage is sent to the sewage vanadium removal unit. Under the neutralization and flocculation of vanadium removal agent, vanadium enters vanadium slag, which is sent to landfill regularly, and the sewage after vanadium removal is discharged into sewage treatment plant for treatment.
The EPR solution polymerization technology of DSM company is mature and advanced, which has the following advantages: (1) low investment and optimized process. The optimum proportion design of the reactor can meet the requirements of reaction material mixing, and can accurately control the polymerization process parameters and product quality. The concentration of polymer glue solution is high, but the amount of circulating solvent is small, the polymerization kettle is small, but the production intensity is high, raw materials and circulating monomers do not need to be refined, the catalyst efficiency is high, the vanadium content in the three wastes is low, and the yield elasticity is high. (2) The production and operation cost is low, the annual operation time of the device is long, the consumption of raw materials and accelerators is low, and the advanced control system is adopted to control the production. (3) The product quality is very competitive. The product has the advantages of low catalyst residue content, less defective products in production, flexible product brand switching, less waste products, adjustable product characteristics according to user's requirements, many product brands, adjustable Mooney value in a wide range of 20 ~ 160, stable quality, good repeatability, narrow product specification range and excellent product processability.
Technical characteristics of 1.2
Mature technology and stable operation are the main methods of industrial production of ethylene-propylene rubber. There are many varieties and brands of products, uniform quality, less ash and wide application range; The product has good electrical insulation performance. However, because the polymerization is carried out in a solvent, the mass transfer and heat transfer are limited, and the mass fraction of polymer is generally controlled at 6% ~ 9%, and the highest is only 1 1% ~ 14%, so the polymerization efficiency is low. At the same time, because the solvent needs to be recovered and refined, the production process is long, there are many equipments, and the construction investment and operation cost are high.