COMPACT solution process

Application Tb produce polyethylene with a very wide density range from. 900 to. 970 using the COMPACT solution process with a single proprietary, advanced Ziegler Natta-type catalyst. As comonomers, either propylene (for high-density range), butene or octene or combinations are used. 

The COMPACT solution process is characterized by its low residence time (few minutes in the reactor and less than 30 minutes in total), thus enabling fast grade changes and wide flexibility for usage with various comonomers. Especially, the octene copolymers are the ultimate in LLDPE grades. 

Stamicarbon bv Polyethylene, LLDPE/HDPE Ethylene/comonomers Compact Solution Process low residence time fast grade changes for hiiji quality LLDPE/HDPE line sizes up to 150,000 tpy 8 1998... 

Stamicarbon BV COMPACT solution process, single proprietary Ziegler-Natta type catalyst, comonomers propylene, butene, octane, or combination. Ethylene conversion exceeds 95%, low residence time, total capacity 650 MMT/y. PE of any density (density 900-970 kg/m ) MFI = 0.8-100 g/10 min for film, injection moulding, pipes, rotomoulding, and extrusion applications crosslinking. 

The largest application segment for filter photometers is in the area of combustion gases analysis, primarily for CO, CO2, hydrocarbons, SO2, etc. Other major areas of application include the petrochemical industry, with natural gas and other hydrocarbon process gas streams being important applications. As measurements become more complex, there is the need for more advanced instrumentation. Variable or tunable filter solutions (as described above) or full-spectrum FTIR or NIR instruments are normally considered for these applications, primarily in terms of overall versatility. Now that array-based systems are becoming available, there is a potential for an intermediate, less expensive, and more compact solution. Note that compact instrumentation tends to be environmentally more stable, and is well suited for industrial applications. 

The solution process is less generic. The companies having a strong technology foothold in the solution process technology include Mitsui, Nova Chemicals (Sclairtech process), Dow and DSM (Stamicarbon Compact process). Differences in process set-up and operating conditions are considered as proprietary information. 

The gaseous ammonia is passed through electrostatic precipitators for particulate removal and mixed with the cooled gas stream. The combined stream flows to the ammonia absorber where the ammonia is recovered by reaction with a dilute solution of sulfuric acid to form ammonium sulfate. Ammonium sulfate precipitates as small crystals after the solution becomes saturated and is withdrawn as a slurry. The slurry is further processed in centrifuge faciHties for recovery. Crystal size can be increased by employing one of two processes (99), either low differential controUed crystallization or mechanical size enlargement by continuous compacting and granulation. 

If aggregate is mixed with dry calcium chloride or a calcium chloride solution and then compacted, the presence of the calcium chloride draws ia moisture to biad the fine particles ia the aggregate matrix. This process leads to a well compacted, maximum deasity gravel road. This appHcatioa for calcium chloride was reviewed ia 1958 (27). More receat pubHcatioas are also available (28—30). 

Carburization by Thermal Diffusion. Carburization of chemically processed metal or metal-compound powders is carried out through sohd-state, thermal diffusion processes, either in protective gas or vacuum. Carbide soHd solutions are prepared by the same methods. Most carbides are made by these processes, using loose or compacted mixtures of carbon and metal or metal-oxide powders. HaUdes of Group 5 (VB) metals recovered from ores by chlorination are similarly carburized. 

Urea possesses negligible basic properties (Kb = 1.5 x 10 l4), is soluble in water and its hydrolysis rate can be easily controlled. It hydrolyses rapidly at 90-100 °C, and hydrolysis can be quickly terminated at a desired pH by cooling the reaction mixture to room temperature. The use of a hydrolytic reagent alone does not result in the formation of a compact precipitate the physical character of the precipitate will be very much affected by the presence of certain anions. Thus in the precipitation of aluminium by the urea process, a dense precipitate is obtained in the presence of succinate, sulphate, formate, oxalate, and benzoate ions, but not in the presence of chloride, chlorate, perchlorate, nitrate, sulphate, chromate, and acetate ions. The preferred anion for the precipitation of aluminium is succinate. It would appear that the main function of the suitable anion is the formation of a basic salt which seems responsible for the production of a compact precipitate. The pH of the initial solution must be appropriately adjusted. 

Later we will describe both oxidation and reduction processes that are in agreement with the electrochemically stimulated conformational relaxation (ESCR) model presented at the end of the chapter. In a neutral state, most of the conducting polymers are an amorphous cross-linked network (Fig. 3). The linear chains between cross-linking points have strong van der Waals intrachain and interchain interactions, giving a compact solid [Fig. 14(a)]. By oxidation of the neutral chains, electrons are extracted from the chains. At the polymer/solution interface, positive radical cations (polarons) accumulate along the polymeric chains. The same density of counter-ions accumulates on the solution side. 

We could again apply the seven-step process in detail. Instead, we take a more compact approach. Begin by determining what species are present in the reaction mixture. Next, use the solubility guidelines to identify the precipitate. After writing the balanced net ionic reaction, use solution stoichiometry and a table of amounts to find the required quantities. 

The interest in hyperbranched polymers arises from the fact that they combine some features of dendrimers, for example, an increasing number of end groups and a compact structure in solution, with the ease of preparation of hn-ear polymers by means of a one-pot reaction. However, the polydispersities are usually high and their structures are less regular than those of dendrimers. Another important advantage is the extension of the concept of hyperbranched polymers towards vinyl monomers and chain growth processes, which opens unexpected possibilities. 

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