PE Introduction

Ⅰ. Overview
PE is a thermoplastic resin obtained by polymerization of ethylene monomers.

Ⅱ. Production Method
1) Gas-phase PE process
The gas-phase PE process is a technology for producing ethylene (co) polymers by low-pressure gas-phase fluid bed dryer method. The gas-phase PE process combines the advantages of metal catalysts and ultra-condensed state processes. The main features of this process are: titanium catalysts, solid chromium catalysts, metallocene catalysts, bimodal catalysts can be used to produce HDPE, LLDPE and VLDPE resin products with different properties. The product density range is usually 0.916-0.961g/cm3, the melt index is 0.1-200, and the relative molecular mass range is 30,000-250,000. Narrow or wide molecular weight distribution can be adjusted according to the catalyst type. The process reactor adopts a vertical gas-phase fluid bed dryer, the reaction pressure is usually 2.4MPa, and the reaction temperature is 80-110℃. Conventional and metallocene catalysts do not require the catalyst removal step. The investment and operating costs are low, and the environmental pollution is less. The single-line capacity can be 40,000-450,000 tons/year.
2) Slurry process
The technical characteristics of the slurry process are that the produced polymer is suspended in a diluent, and the pressure and temperature during the production process are relatively low. The slurry process is the main method for producing HDPE.
3) Solution process
Features of PE solution process: low raw material requirements, short reaction residence time, fast polymerization reaction rate, short product switching time, use of solvents, stable reaction, no reactor scaling, easy operation of start-up and shut-down, high conversion rate, ethylene single-pass conversion rate can reach 95%, total utilization rate can reach 98.5%, can produce a full range of products (molecular weight distribution from narrow to wide distribution) and LDPE; can be copolymerized with high-grade α-olefins.
4) High-pressure PE process
The high-pressure LDPE production process can be divided into two types: high-pressure tubular reactor and autoclave reactor. The two process steps are similar. The tubular reactor has a simple structure, is easy to manufacture and maintain, and can withstand higher pressures. The autoclave reactor has a complex structure and is difficult to maintain and install. The PE molecules of autoclave reactor have many long chain branches, wide molecular weight distribution, good impact strength, and are easy to process. The products are suitable for extrusion, coating, and high-strength heavy-load film production. The PE molecules of tubular reactor have fewer long chain branches, narrow molecular weight distribution, and better optical properties, which are suitable for the production of transparent packaging films.

Ⅲ. Application
High-pressure PE: more than half is used for film products, followed by pipes, injection molded products, wire wrapping layers, etc.
Medium and low-pressure PE: mainly injection molded products and hollow products.
Ultra-high-pressure PE: Due to the excellent comprehensive properties of ultra-high molecular PE, it can be used as an engineering plastic.

IV. Conclusion
PE is a widely used basic material, and the quality control of its drying process plays a vital role in the final performance of the product. Tianli Energy Co., Ltd., with its excellent technology and rich experience, is in a leading position in the field of PE, LDPE, and HDPE drying, and has won the trust of many partners.