Reactors middle-pressure

Fig. 6. Different stage II parallel reactors. Left 49 channel reactor for normal pressure and temperatures up to 450°C (from ref. 31). Middle 49 channel reactor for pressures up to 50 bar and temperatures up to 260°C (from ref. 32). Right Modular slice reactor which can be expanded in multiples of four (courtesy of hte Aktiengesellschaft).

Figure 12.3b shows a middle-pressure reactor in which the catalyst is located in vertical tubes. Some 2000 such tubes were connected into bundles and immersed into boiling water. This reactor type was also utilized in many large installations, and it was found that they could be operated satisfactorily. 

The nonlinear dependence of the reaction rate on the partial pressure of CO suggests that there are stimulated either a single reaction step with the established nonlinearity or at least two steps, one of which has a linear and the other one a nonlinear (nperiodic operation of the reactor at the 180°C level and at a middle oxidation state (pretreatment at p /p = 5,0).has been accomplished (see Figure 9) with a H fl/N testing mixture followed by a C0/N recuperation mixture. After an intermediate activity of the catalyst has been attained by this periodic operation, CO has been added in the testing mixture. 

CO, reforming reaction was conducted at 500-750°C, reactants mole ratio of CH3 CO, He = 1 1 3, and space velocity = 20000-80000 1/kg/h. Methane oxidation was conducted at 150-550 °C using 1 % CH in air mixture (2 ml/min CH4 198 ml/min air) at space velocity = 60000 1/kg/h, and MIBK (4000 ppm in 150 ml/min air introduced by a syringe pump) combustion at 100-500°C and space velocity of 10000-30000 h 1. Catalytic reactions were conducted in a conventional flow reactor at atmospheric pressure. The catalyst sample, 0.1-0.3g was placed in the middle of a 0.5 inch I.D. quartz reactor and heated in a furnace controlled by a temperature programmer. Reaction products were analyzed by a gas chromatography (TCD/FID) equipped with Molecular Sieves 5A. Porapak Q, and 15m polar C BP 20 capillary column. 

Municipal solid wastes (MSW) gasification unit which is under development in the project consists of two fluid bed reactors (Figure 2). The first reactor is a gasifier, the second reactor is a combustion chamber for charcoal. To obtain producer gas of middle calorific value water steam is applied as a blowing. Fluid bed is organized by supplying water steam to gasifier (inert material is sand) and air to combustion chamber. The installation is equipped with all necessary devices to measure rate, temperature, and pressure. 

This insight provided by the model and confirmed by the pilot plant experiments led to modifications in the large plant reactor. Liquid was returned to both ends and to the middle of the vessel. These simple plumbing modifications permitted the plant to use higher pressure setpoint ramp rates and at the same time reduced the frequency of disk ruptures. The higher TML yields and the shorter batch times increased production rates. 

In Fig. 4.6 we have plotted a typical heat generation expression (curve a) along with the heat removal line, b. In this case the two curves intersect at three locations corresponding to three different reactor conditions that are possible for the same operating parameters and feed conditions. The low-temperature steady state is uneconomical since the feeds are virtually unconverted. The highest-temperature steady state has nearly complete conversion but may be too hot. Under those conditions side reactions may set in or the reactor pressure becomes too high. The middle steady state strikes a good compromise and is where... 

The kinetic studies were done in a 1/2-inch pipe jacketed reactor with a 1/8-inch thermowell down the middle. The first 7 inches of the reactor was filled with quartz chips and used as a preheater. Ten grams of 10-20 mesh SK-500 was then mixed with twice its volume of quartz and placed on top of the preheat section. The feed was pre-mlxed In a pressurized tank and then pumped upflow through the reactor. The temperature was controlled by pumping Dow Therm through the jacket with heat being supplied externally. This resulted In the reactor being Isothermal. 

Diluent in microflow test Silicon carbide, d = 0.05 mm. Feed Middle East heavy gasoil, 1.64 %w S.Operating conditions WHSV, WABT, hydrogen/oil ratio, partial pressures of hydrogen and hydrogen sulfide same in commercial and microflow reactor. 

In the Smuda process the pyrolysis reactor temperature is 350°C and the operating pressure is 4-5 psi. The pyrolysis gases from the pyrolysis vessel are sent directly to a distillation column. The distillation column has a typical temperature profile as follows top 140°C, Sulzer 250Y middle 322°C, Sulzer 350Y and bottom 331°C. 

Vapor phase catalytic hydrodechlorination of 1,1,1-trichloroethane (TCA) has been studied using various supported platinum catalysts in a plug microflow reactor. The reactor was operated at temperatures ranging from 250 to 350°C, a H2 TCA He ratio of 10 1 89, a space velocity of 24 L/g cat-h, and atmospheric pressure. To study the deactivation process, tests were carried out by dividing the catalyst bed into three segments (inlet, middle, outlet) separated by glass wool plugs. 

The Mizushima Oil Refinery of Japan Energy Corporation first implemented an operation of vacuum residue hydrodesulfiirization in the conventional fixed bed reactor system in 1980. We have also conducted a high conversion operation to produce more middle distillates as well as lower the viscosity of the product fuel oil to save valuable gas oil which is used to adjust the viscosity. Vacuum residue hydrodesulfurization in fixed bed reactors mvolves the characteristic problems such as hot spot occurrence and pressure-drop build-up. There has been very little literature available discussing these problems based on commercial results. JafiFe analyzed hot spot phenomena in a gas phase fixed bed reactor mathematically, assuming an existence of the local flow disturbance region [1]. However, no cause of flow disturbance was discussed. To seek for appropriate solutions, we postulated causes ofhot spot occurrence and pressure-drop build-up by conducting process data analysis, chemical analysis of the used catalysts, and cold flow model tests. This paper describes our solutions to these problems, which have been demonstrated in the commercial operations. 

Palladium and palladium-silver alloy membranes on porous alumina tubes were prepared by means of simultaneous and sequential electroless plating techniques [234], The membrane reactor was used for the direct formation of hydrogen peroxide by catalytic reaction of H2 and 02 at 293 K. The concentration of H202 increased with increases in the transmembrane partial pressure gradient of H2. A high concentration of H202 was obtained with a membrane that consisted of a palladium layer on the outer surface, porous alumina in the middle, and a palladium-silver alloy layer on the inside. 

There is a middle steady state, but it is metastable. The reaction will tend toward either the upper or lower steady states, and a control system is needed to maintain operation around the metastable point. For the styrene polymerization, a common industrial practice is to operate at the metastable point, with temperature control achieved by boiling. A combination of feed preheating and jacket heating ensures a positive heat balance so that the uncontrolled reaction would tend toward the upper, runaway condition. However, the reactor pressure is set so that the system boils when the desired operating temperature is reached. The latent heat of vaporization plus the return of subcooled condensate maintains the temperature at the boiling point. 

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