Vessel-type reactors

In the process, homopolymer and random copolymer polymerization occurs in the loop-type reactor (or vessel-type reactor) (1). For impact copolymer production, copolymerization is performed in a gas-phase reactor (2) after homopolymerization. The polymer is discharged from a gas-phase reactor and transferred to the separator (3). Unreacted gas accompanying the polymer is removed by the separator and recycled to the reactor system. The polymer powder is then transferred to the dryer system (4) where remaining propylene is removed and recovered. The dry powder is pelletized by the pelletizing system (5) along with required stabilizers. 

Description Liquid or gaseous ethylene is fed, together with a solvent and required comonomer(s) into a stirred, liquid-filled, vessel-type reactor (1). The reactor is operated adiabatically thus, the feed is precooled. All heat of reaction is used to raise polymerization temperature up to approximately 200°C. Hydrogen is used to control polymer molecular weight. A high-activity, proprietaiy catalyst is prepared onsite from commercially available components. Ethylene... 

The most common types of SCWO reactors are cylindrical vessels or pipes. The vessel-type reactors (i.e., length/diameter ratio <20) typically have a vertical orientation with process flow directed downward. Pipe reactors (i.e., length/ diameter ratio >100) typically are mounted horizontally and are often coiled, since they need to be longer than vessel reactors to achieve the same residence time. SCWO reactors may have external heating (e.g., heating coils, steam jacket) or may rely solely on heated process fluid and the heat of reaction to reach and maintain the desired internal temperature under steady-state conditions. 

The VKR-MT is a vessel type reactor with the core based on micro fuel elements directly cooled by boiling water. VKR-MT is an English spelling of the Russian abbreviation for boiling water reactor with micro fuel elements. 

The PBWFR concept [XXVII-1] is an evolution of the concept of a direct contact Pb-Bi fast breeder reactor (PBWR) proposed in [XXVII-2]. It is a pressure vessel type reactor, in which sub-cooled water is fed into the hot Pb-Bi coolant above the core, resulting in a direct contact boiling, as shown in Fig. XXVII-1. Boiling bubbles rise due to buoyancy effect, which also works as a lift pump for Pb-Bi circulation. The generated steam passes through the separator and the dryer to remove Pb-Bi droplets, and then flows to the turbine-generator plant. The outlet steam is superheated by 10°C to avoid the accumulation of condensate on a free Pb-Bi surface in the reactor vessel. 

A preconceptual plant design with 1700 M W net electric power based on a pressure vessel-type reactor has been studied by Yamada et al. (2011) and has been assessed with respect to efficiency, safety, and cost. The study confirms the target net efficiency of 44% and estimates a cost reduction potential of 30% compared with current pressurized water reactors. Safety features are expected to be similar to advanced boiling water reactors. 

Reactors. Reactors are a special type of vertical vessel. Some reactors are also in horizontal vessels but this is rare. Reference 7 covers reactors in more detail (see also Reactor technology). Reactors provide the means by which chemical reactions occur to transform feedstocks into products. 

The effect of physical processes on reactor performance is more complex than for two-phase systems because both gas-liquid and liquid-solid interphase transport effects may be coupled with the intrinsic rate. The most common types of three-phase reactors are the slurry and trickle-bed reactors. These have found wide applications in the petroleum industry. A slurry reactor is a multi-phase flow reactor in which the reactant gas is bubbled through a solution containing solid catalyst particles. The reactor may operate continuously as a steady flow system with respect to both gas and liquid phases. Alternatively, a fixed charge of liquid is initially added to the stirred vessel, and the gas is continuously added such that the reactor is batch with respect to the liquid phase. This method is used in some hydrogenation reactions such as hydrogenation of oils in a slurry of nickel catalyst particles. Figure 4-15 shows a slurry-type reactor used for polymerization of ethylene in a sluiTy of solid catalyst particles in a solvent of cyclohexane. 

Stein et al. used fatty acid esters and vaporized S03 diluted with air [41,45]. The apparatus was a cascade-type reactor with Five vessels. In each vessel a... 

Another example of microwave-assisted PSR chemistry involves the rapid conversion of amides to thioamides by use of a polystyrene-supported Lawesson-type thio-nating reagent. By use of microwave irradiation at 200 °C in sealed vessels (monomode reactor), a range of secondary and tertiary amides was converted within... 

In this section we have presented modeling results for industrial type IV FCC units that produce high octane number gasoline from gas oil. Such units consist of two connected bubbling fluidized beds with continuous circulation of the catalyst between the two vessels, the reactor and the regenerator. The steady-state design equations are nonlinear transcendental equations which can be solved using the techniques described in the earlier chapters of the book. 

Several types of batch reactors are considered in this chapter. In a pure batch reactor all the reactants are charged initially to the vessel. The reactor is heated to the desired reaction temperature and products are formed. At the termination of the batch cycle, the products are removed. The inherent problem with this type of batch reactor is that all the fuel is sitting in the vessel. If temperature is increased too quickly or if adequate heat transfer area is not available, an exothermic reaction can easily cause a runaway. 

With those single-mode reactors that do not require a minimum filling volume (CEM Discover platform temperature measurement is performed from the bottom and not from the side by an external IR sensor) even volumes as low as 50 xL can be processed [57]. With the commercially available singlemode cavities of today, the largest volumes that can be processed under sealed vessel conditions are ca 50 mL, with different vessel types being available to upscale in a linear fashion from 0.05 to 50 mL. Under open vessel conditions higher volumes (> 1000 mL) have been processed under microwave irradiation conditions, without presenting any technical difficulties as, e.g., described for the synthesis of various ionic liquids on a 2 mol scale [35]. 

The ideal cell in order to scale up an electrochemical reaction can depend on the reaction, the electroactivity of the substrate to convert, the concentration of the substrate, as well as the current density at the working electrode. The use of a separator is necessary when the electrode can affect the whole process negatively. With anodic oxidations, the reaction at the counter electrode is most frequently the cathodic formation of hydrogen. In these cases, a separator does not seem indispensable a tank cell (kind of Grignard type reactor equipped with cylindrical electrodes) or a capillary-gap cell (piling of bipolar electrodes in a cylinder-shaped vessel connected to an anodes and a cathode located at the top and the bottom of the cell) can be considered as suitable devices for anodic conversions. More generally, the so-called plate-and-frame cells (Fig. 4) are used in a battery. 

Care must be exercised in deciding when Eq. (2-4) is applicable. In a flow reactor, used for a gaseous reaction with a change in moles, it is not correct (see Examples 4-3 and 4-4). However, it is correct for all gas-phase reactions in a tank-type reactor, since the gaseous reaction mixture fills the entire vessel, so that the volume is constant. For many liquid-phase systems density changes during the reaction are small, and Eq. (2-4) is valid for all types of reactors. The use of Eqs. (2-1) to (2-4) will become clear as we consider various kinds of reactions and reactors. 

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