4, bulk method - gas phase combination process The bulk-gas combination process includes Basel's Spheripol process, Japan's Mitsui Chemicals' Hypol process, and Borealis's Borstar process. (1) Spheripol process. The Spheripol process was successfully developed by Basell Polyolefins. Since its first industrialization in 1982, this technology has been the most successful and widely used polypropylene production process to date. Spheripol process is a liquid phase prepolymerization combined with liquid phase homopolymerization and gas phase copolymerization. The process adopts high-efficiency catalyst. The resulting PP powder particle size has the spherical shape of the powder produced by the catalyst, and the particles are large and uniform. Can be adjusted, both wide and narrow. Can produce a wide range of multi-purpose products. Its homo- and random copolymer products are characterized by high clarity, good optical properties and no odor. The liquid loop reactor used in the Spheripol process has the following advantages: At present, the technology has been developed to the second generation. Compared with the first-generation technology using a single loop reactor, the second-generation technology uses a double loop reactor, operating pressure and temperature are significantly increased, and bimodal polypropylene can be produced. The catalyst system adopts fourth- or fifth-generation ZN high-efficiency catalysts, increases the hydrogen separation and recovery unit, improves the high-pressure and low-pressure degassing equipment of the polymer, and the steaming, drying and propylene accident discharge units have also been improved, increasing the operation. Flexibility, increased efficiency, and significant reductions in raw material monomer and utility consumption. The resulting product has a more uniform particle size, a wider range of melt flow index (from 0.3-1600.0 g/10 min), and can produce new PP grades with high rigidity, high crystallinity, and low heat sealing temperature. The impact copolymerization of the Spheripol process is produced by the gas phase process. The reactor is one or two dense-phase fluidized bed reactors connected in series. The reactor was a gas phase dense fluid bed. A gas phase reactor system can be used to produce impact copolymers with an ethylene content of 8% to 12% (mass fraction) if it is desired to produce special impact copolymers with a higher rubber phase content and possibly more than one dispersed phase (eg, low For stress-whitening products, two gas phase reactor systems need to be designed to maintain the gas phase composition and operating conditions independently in the two gas phase reactor systems, and two different copolymers can be added to the homopolymer. The steam and dry two-step treatment of the polymer can easily condense the steam in the steam tail gas to separate the pure hydrocarbon monomers, completely recover the hydrocarbons in the tail gas, and reduce the monomer consumption. The closed circuit nitrogen drying system also reduces the nitrogen consumption of the unit. In addition, the Spheripol process adopts a modular design method, which can meet the requirements of different users, and is easy to be constructed step by step (for example, the homopolymer production system is firstly added, and the gas phase reaction system is added at a proper time), and the production capacity of the device is also easy to expand. Spheripol process has a strict and perfect safety system design, so that the device has high operational stability and safety. The new generation of Spheripol process uses pure additives to add the system, so that the product quality is more uniform and stable, and it is convenient for product switching. Spheripol process technology offers a full range of products, including homopolymers, random copolymers, impact copolymers, terpolymers (ethylene-propylene-butene copolymers). The MFR of its homopolymer products ranged from 0.1 to 2000 g/10 min, the MFR of industrial products reached 1860 g/10 min (special non-granulated products), and the flexural modulus of high-rigidity products reached 2300 MPa. Ethylene content up to 4.5% (mass fraction) in industrially produced random copolymer products, and ethylene-propylene-butylene terpolymer products, film sealing starting temperature as low as 110 °C, can be produced with the gas phase process The high ethylene content random copolymers compete. The impact copolymer product has a very good combination of rigidity and impact resistance, the product ethylene content can be as high as 25% (40% rubber phase), and has the ability to reach 40% ethylene content (60% rubber phase). In addition, the Spheripol process can be used to produce MFR up to 1800 g directly in the reactor by adding peroxides and double loop reactors with the flexibility to adjust the molecular weight distribution of the product within the polymer dispersion index (PI) of 3.2-12 according to product requirements. 10min products and big ones Stripe Blouse,Women Stripe Blouse,Women Flannel Collar Blouse,Flannel Turn Down Collar Blouse Shaoxing Bosheng Garment-Making Co.,Ltd. , https://www.boshengshirt.com
(a) High reactor hour-space yield (up to 400 kgPP/h.m3), smaller reactor volume, and lower investment;
(b) The reactor has a simple structure, low material requirements, low temperature carbon steel, and simple design and manufacture. Due to the small diameter (DN500 or DN600), even if the pressure is higher, the wall of the tube is thinner;
(c) The straight leg portion of the jacketed reactor may serve as the backbone of the reactor frame, and this structural design reduces investment;
(d) Due to the small reactor volume and short residence time, product switching is fast and there is less transition material;
(e) The polymer particles are suspended in propylene liquid with good heat transfer between the polymer and propylene. With the cooling jacket, the heat transfer area per unit volume of the reaction heat is large, the heat transfer coefficient is large, and the overall heat transfer coefficient of the loop reactor is as high as 1600W/(m2.°C);
(f) The slurry in the loop reactor is circulated at high speed by means of an axial pump. The flow rate of the fluid is as high as 7 m/s, so that the polymer slurry can be uniformly stirred, the catalyst system can be distributed uniformly, and the polymerization conditions can be easily controlled and can be controlled accurately. The product quality is uniform, it is not easy to produce hot spots, it is not easy to stick to the wall, and the energy consumption of the axial flow pump is also low;
(g) The polymer slurry concentration in the reactor is high (mass fraction is greater than 50%), the single-pass conversion of the reactor is high, and the homo-conversion rate of propylene per pass is 50% to 60%. These characteristics make the loop reactor very suitable for producing homopolymers and random copolymers. The Spheripol process starts with the use of highly efficient catalysts such as GF-2A, FT-4S and UCD-104. The catalyst activity reaches 40kgPP/gcat. The isotacticity of the product is 90% to 99%, and it is not necessary to remove ash or to remove irregular substances.