Continuous fluidized bed reactor process

Fresh styrene and catalyst components are fed to the fluidized bed reactor (V-300). In the reactor, styrene is polymerized to SPS in the presence of catalysts. The SPS powder is fluidized in the jacketed vessel with a helical ribbon mixer. The polymerization conditions are 70 °C and 225 mmHg under nitrogen flow. Unreacted styrene is taken out from the reactor by a nitrogen flow. Polymerization heat is removed by the evaporation heat of styrene and the jacket coolant. 

SPS powder is discharged from the bottom of the fluidized bed reactor. The styrene vapor from the top of the reactor is cooled with cooling water (E-310) and chilled with brine (E-320) in heat exchangers. Most of the styrene vapor is condensed in heat exchangers. The styrene condensate is recycled to the reactor. 

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Figure 12.4 shows the flow diagram of the continuous fluidized bed reactor process. 

Figure 12.4 Flow diagram of a continuous fluidized bed reactor process. V-300 fluidized bed reactor E-310 1. Fleat exchanger V-310 1. Surge tank E-320 2. Heat exchanger V-320 2. Surge tank C-320 vacuum pump.

The second process is a continuous fluidized bed reactor. In an Idemitsu Petrochemical patent [7], a helical ribbon mixer is adopted. High power consumption and high SPS conversion are important to avoid adhesions. In this process, the polymerization heat is removed by the evaporation heat of styrene and by the jacket coolant. 

The use of a fluidized-bed reactor is possible only when the reactants are essentiaUy in the gaseous phase. Eluidized-beds are not suitable for middle distiUate synthesis, where a heavy wax is formed. Eor gasoline synthesis processes like the MobU MTG process and the Synthol process, such reactors are especiaUy suitable when frequent or continuous regeneration of the catalyst is required. Slurry reactors and ebuUiating-bed reactors comprising a three-phase system with very fine catalyst are, in principle, suitable for middle distiUate and wax synthesis, but have not been appHed on a commercial scale. 

FIG. 23-24 Reactors with moving catalysts, a) Transport fluidized type for the Sasol Fischer-Tropsch process, nonregenerating, (h) Esso type of stable fluidized bed reactor/regeuerator for cracldug petroleum oils, (c) UOP reformer with moving bed of platinum catalyst and continuous regeneration of a controlled quantity of catalyst, (d) Flow distribution in a fluidized bed the catalyst rains through the bubbles. 

Weuster-Botz, D., Aivasidis, A., and Wandrey, C., Continuous Ethanol Production by Zymomonas mobilis in a Fluidized Bed Reactor. Part II. Process Development for the Fermentation of Hydrolysed B-Starch without Sterilization, Appl. Microbiol. Biotechnol., 39 685 (1993)... 

After preparation of this review, an abstract by Godde A, Kragl U, Biselli M, Katapodis A, Bowen BR, Ernst B, Wandrey C, was published on the XVIIIth International Carbohydrate Symposium, July 21-26, 1996, Milano, Italy (BP 135, p 390). It reports the large-scale production of 1800 units of a recombinant human al-3 fucosyltransferase (FucT VI, EC. 2.4.1.152) in its soluble form with a CHO cell line in a continuous fermentation process in a fluidized bed reactor (34mUmg 1 in culture supernatant). After partial purification the specific activity yielded 220 mU mg ... 

The Unipol process employs a fluidized bed reactor (see Section 3.1.2) for the preparation of polyethylene and polypropylene. A gas-liquid fluid solid reactor, where both liquid and gas fluidize the solids, is used for Ziegler-Natta catalyzed ethylene polymerization. Hoechst, Mitsui, Montedison, Solvay et Cie, and a number of other producers use a Ziegler-type catalyst for the manufacture of LLDPE by slurry polymerization in hexane solvent (Fig. 6.11). The system consists of a series of continuous stirred tank reactors to achieve the desired residence time. 1-Butene is used a comonomer, and hydrogen is used for controlling molecular weight. The polymer beads are separated from the liquid by centrifugation followed by steam stripping. 

The use of a fluidized-bed reactor has a number of advantages in the MTO process. The moving bed of catalyst allows the continuous movement of a portion of used catalyst to a separate regeneration vessel for removal of coke deposits by burning with air. Thus, a constant catalyst activity and product composition can be maintained in the MTO reactor. Figure 12.10 demonstrates the stability of a 90 day operation in the fluidized-bed MTO demonstration unit at the Norsk Hydro Research Center in Porsgrunn, Norway. A fluidized-bed reactor also allows for... 

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