Reactor operating temperature

Some reactors are designed specifically to withstand an explosion (14). The multitube fixed-bed reactors typically have ca 2.5-cm inside-diameter tubes, and heat from the highly exothermic oxidation reaction is removed by a circulating molten salt. This salt is a eutectic mixture of sodium and potassium nitrate and nitrite. Care must be taken in reactor design and operation because fires can result if the salt comes in contact with organic materials at the reactor operating temperature (15). Reactors containing over 20,000 tubes with a 45,000-ton annual production capacity have been constmcted. 

Reactor type Single-channel reactor Operating temperature 530 0... 

GP 4] [R 5] For an undisclosed methanol derivative, no hot spot (close to 0 K rise) was found for the construction-material silver micro reactor (operational temperature 390 °C) hot spots of 160 and 60 K were found for laboratory pan-like (40% 50% 550 °C) and short sheU-and-tube reactors, respectively, using elemental silver [1,49-51, 108]. 

The Influence of Selectivity Considerations on the Choice of Reactor Operating Temperatures... 

A typical FCC operation can yield around 4-5 wt% propylene. The inclusion of ZSM-5 additives (Zeolite structural matrix-5) coupled with high reactor operating temperature (ROT) yields 5-10 wt% propylene with additive concentrations up to 10 wt% as per the industry standard as shown in the table below. This is based on data from commercially operating units around the world. A comparison of propylene yield from various catalytic cracking options is summarized below ... 

The reactor operating temperature condition of 700°C was chosen on the basis that this was slightly above 650°C found in previous experiments to be the temperature below which little reaction with the lignite was noted. The 1500 psi operating pressure is the upper safety limit of the reactor at the 700°C temperature. Lower pressures tended to result in lower liquid yields. A thorough investigation of the effect of pressure is yet to be made. 

Hydrogenic ion-induced blistering has been observed, but by itself will not likely present a problem to the first wall at elevated reactor operating temperatures. The effects of blistering at high primary fluxes such as those found at beam dumps and components of neutral beam injectors, divertor throats and bombardment plates, are not known. 

Raising a reactor operating temperature within the safe operating envelope. 

Calculate the reaction rate constant at the reactor operating temperature. Since the temperature in the reactor is not 25°C (where the value for the reaction rate constant is known), the rate constant must be estimated at the reactor temperature. The Arrhenius form of the rate constant may be used to obtain this estimate ... 

Description The Isomar process re-establishes an equilibrium distribution of xylene isomers, essentially creating additional paraxylene from the remaining ortho- and meta-xylenes. The feed typically contains less than 1 wt% of paraxylene and is first combined with hydrogen-rich recycle gas and makeup gas. The combined feed is then preheated by an exchanger (1) with reactor effluent, heated in a fired heater (2) and raised to the reactor operating temperature. The hot feed vapor is then sent to the reactor (3), where it is passed radially through a fixed-bed catalyst. 

The reaction equilibrium constant at the reactor operating temperature is... 

Identify the process operating equipment constraints, conditions for reliable operation, and shutdown limits. For example, reactor operating temperatures should be 25°C less than the maximum temperature of the catalyst. 

Here the first term is the energy required for isothermal chemical reaction at the reactor feed temperature, and the second term is the energy required to heat the reaction mixture, without further reaction, from the inlet temperature to the reactor operating temperature. 

Variables Studied. The main independent variables investigated were the pulping base (Na, Ca, or Mg) and the reactor operating temperature. The latter was explored for each type of liquor at least at two levels. Other operating variables, which from earlier experiments were known to have a lesser effect on the most important dependent variables, were only spot checked. These were the feed rate, the reactor pressure, and the solids concentration—i.e., water-.organics ratio. The particular (nominal) levels of operating parameters chosen were ... 

For the specific jacket-cooled CSTR process considered in this section and the next, a simple heuristic approach can be used to incorporate quantitatively the limitations of controllability into the steady-state design. The idea is to specify a design criterion that ensures good controllability. In the reactor temperature control problem we use the criterion of a specified ratio of the maximum heat removal rate to the heat removal rate at design conditions. This simple approach is easily understood by designers and operators, and it requires no dynamic simulation or control analysis. We illustrate its usefulness in the following section to determine the besf reactor operating temperature. 

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