Oligomerization reactor

The heat of the reaction is removed by water-cooled heat exchangers between the reactors (see Figure 3). In a high pressure separator the insoluble products and the catalyst solution as well as unreacted ethylene are separated. The catalyst solution is fed back into the oligomerization reactor. Washing of the oligomers by fresh solvent in a second separation step removes traces of the catalyst. In a series of distillation columns the a-olefins are separated into the desired product fractions. 

Fig. 1 a) Oligomerization reactor shown schematically b) Reactor tube detail. 

The methanol-to-gasoline route proved in New Zealand starting in 1985 (Mobil MTG process), which includes an improved MTG fluid-bed oligomerization reactor that... 

Partial Oxidation to Methanol. - In this technique, at elevated pressure (60 atm), methane is selectively oxidized with 99.5% oxygen to produce methanol and formaldehyde in a 4 1 ratio. A low conversion per pass (5.5%) is used to obtain 80% selectivity. Temperature increases from 750 °F at the inlet to 930 F at the outlet. The reaction product is expanded at 45 atm pressure and fed directly to a fixed-bed ZSM-5 oligomerization reactor where gasoline and by-product water are produced. Light... 

The formation of insoluble polyethene causes problems also in other parts of the process. During catalyst preparation this can be avoided by adding the preformed, stable nickel complex and the chelate ligand separately to the oligomerization reactor. 

After the oligomerization reactor and the liquid-liquid separator, the organic product has to undergo an intensive product wash to make sure that no catalyst enters the distillation columns. In the following series of distillations, the technically desired 1-alkene cut Ce-Cig is separated and the too light C4 and the too heavy C18+ cuts are combined and isomerized to internal linear olefins in the isomerization reactor. These internal alkenes are then converted in the metathesis reactor to form internal alkenes. The desired C -Cig fraction is isolated, whereas the lights and the heavies are again recycled into the isomerization reaction. 

Figure I Basic layout of a plant for the production of oligoethylenes. 1 solution vessel for TiCU 2 solution vessel for Al(C2H5)i, Cli 5 3 pumps 4 oligomerization reactor 5 vessel for freezing agent 6 freezing agent 7 heat exchanger 8 deactivation vessel 9 tank for alkaline solution 10, 13 separators 11 condenser 12 filter. (Adapted from Ref. 171.)...

Shell Higher Olefins Process (SHOP). In the Shell ethylene oligomerization process (7), a nickel ligand catalyst is dissolved in a solvent such as 1,4-butanediol (Eig. 4). Ethylene is oligomerized on the catalyst to form a-olefins. Because a-olefins have low solubiUty in the solvent, they form a second Hquid phase. Once formed, olefins can have Htfle further reaction because most of them are no longer in contact with the catalyst. Three continuously stirred reactors operate at ca 120°C and ca 14 MPa (140 atm). Reactor conditions and catalyst addition rates allow Shell to vary the carbon distribution. 

Figure 9-4. The Octol Oligomerization process for producing Os s and Ci2 s and Cis s olefins from n-butenes (1) multitubular reactor, (2) debutanizer column, (3) fractionation tower.

A two-step methanolysis-hydrolysis process37 has been developed which involves reaction of PET with superheated methanol vapors at 240-260°C and atmospheric pressure to produce dimethyl terephthalate, monomethyl terephthalate, ethylene glycol, and oligomeric products in the first step. The methanolysis products are fractionally distilled and the remaining residue (oligomers) is subjected to hydrolysis after being fed into the hydrolysis reactor operating at a temperature of ca. 270°C. The TPA precipitates from the aqueous phase while impurities are left behind in the mother liquor. Methanolysis-hydrolysis leads to decreases in the time required for the depolymerization process compared to neutral hydrolysis for example, a neutral hydrolysis process that requires 45 min to produce the monomers is reduced... 

Figure 7 shows a simplified scheme of the oligomerization process. The ethylene is compressed in compressor C and fed into reactors R1-R3. It finds its way into the vessel VI in which the catalyst solution is stored. The ethylene enriched catalyst solution, as shown in Fig. 7, proceeds to the reactors. Heat from the reactors is led off through heat exchangers situated between the... 

FIG. 7 Oligomerization of ethylene (reaction part). C, compressor R, reactor S, separator V, vessel. 

The resin system selected to initiate these studies is a step-growth anhydride cured epoxy. The approach to the kinetic analysis is that which is prevalent in the chemical engineering literature on reactor design and analysis. Numerical simulations of oligomeric population density distributions approximate experimental data during the early stages of the cure. Future research will... 

The catalytic ethylene oligomerization was performed in a 0.3 L well-mixed three-phase reactor operating in semi-batch mode, at constant temperature (70 or 150 °C) and pressure (4 MPa of ethylene) in 68 g of n-heptane (solvent). Prior to each experiment, the catalyst was successively pretreated, firstly in a tubular electrical furnace (550 °C, 8 h) and then in the oligomerization autoclave (200 °C, 3 h), under nitrogen flow at atmospheric pressure. After 30 min of reaction, the autoclave was cooled at -20 °C and the products were collected, weighted and analyzed by GC (FID, DB-1 60 m capillary column). 

Mechanistic details of the microwave-induced oligomerization of methane on a microporous Mn02 catalyst were studied by Suib et al. [67], with emphasis on fundamental aspects such as reactor configuration, additives (chain propagators, dielectrics), temperature measurements, magnetic field effect, and reaction conditions. 

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