Heat exchange capacities

The exact size of a heat exchanger needed on a new system cannot be accurately calculated because of too many unknown factors. On existing systems, by making tank measurements and measuring air and oil temperatures, a rather accurate calculation can be made of the heat exchanger capacity needed to reduce the maximum oil temperature. 

In case of exothermic reactions, the heat-exchange capacities of the reactor allow to rapidly evacuate the heat generated by the reaction and therefore to perform a transposition of a pure batch operating mode into a continuous one. The main point is the ability to avoid, as far as possible, an initial increase of the temperature as soon as the reactants are mixed. 

Mechanical agitator (hollow-shaft turbine) Medium to high 900Wm 2 K, limited exchange area Heat exchange capacity... 

Since the numerical values of TL and YL are dependent on the heat exchanging capacity (as shown by equation 3.106), the quantity on the right-hand side of equation 3.110 may be displayed as a function of the inlet temperature to the bed, T0, with T as a parameter. The three bell-shaped curves in Fig. 3.30 are for different values of T and each represents the locus of values given by the right-hand side of this equation. The left-hand side of the equation may be represented by a straight line of unit slope through the point (rCi, 0). The points at which the line intersects the curve represent solutions to equation 3.110. However, we seek only a stable solution which coincides with a high yield. Such a solution would be represented by... 

Where little space is available Where normahto-costly construction materials are mandated Where future expansion of heat-exchanger capacity is probable Where little space is available... 

Problem areas Circulating pump (viscous slurries), continuous feed addition Heat-exchange capacity... 

We consider the reactor here to be operated adiabatically, with T > Tq > Tf. A measure of the heat-exchange capacity of the system is given by... 

The heat transfer between the solid particles and the fluid follows the local thermal non-equilibrium model. The volumetric heat transfer coefficient hv represents the heat exchanger capacity of the porous media. In the current paper, we will investigate the volumetric convection heat transfer coefficient by numerical simulation results of the... 

To be used when heat removal is the main problem additional heat exchange capacity must be added when needed... 

The steam costs are modest provided that good heat exchange can be maintained between the hot stripped water being discharged (Fig. 3.4) and the feed to the stripper. Effluent water is, however, liable to pick up impurities and there should be provision for ample heat exchange capacity and cleaning of both sides of the heat exchanger. 

Performance and parameters Refrigerating capacity 3.5kW, heat exchange capacity 3.5kW, fan capacity 350m3/h... 

Fischer-Tropsch synthesis is another industrially important case where the quest for a catalyst with higher rate as well as selectivity continues. This synthesis is exothermic, and catalysts with higher activity (higher rates) will impose a burden on the heat exchanging capacity of the multiphase reactor used. Development of better catalysts must be accompanied by multiphase reactors that can cater to the higher exotherm associated with faster rates. Section 3.4.1.4 discusses the various available reactor options. 

The heat exchanger capacity can be increased, while keeping the surface area constant. 

In designing an electrolytic plant it is essential to know accurately the amount of energy consumed in order to supply required sources of heat and to have necessary heat exchanger capacity available for addition or removal of heat. A heat or energy balance has to be performed, using the laws of thermodynamics. Only the outlines can be discussed here for further study, the reader is referred to a standard book of physical chemistry such as that by W. J. Moore. 

On the basis of the dynamical inversion (Eq. 41), the application of the recursive motion design procedure presented in subsection 2.6, yielded (after a few self-correcting iterations) the nominal operation presented in Figure 1 (dashed lines), with the following observations (i) The batch productivity is limited by the heat exchange capacity within a standard safety... 

The latest updates in the production from benzene include the Polynt s high load technology, which consists of the retrofitting of the existing multi-tubular reactors, introducing an improved heat exchange capacity, a new benzene evaporator and an air mixing unit and the use of a specific catalyst based on Vanadium and Molybdenum Oxides. 

Numerically, Fig. 27.3 s heat exchanger must be enlarged to handle 10% more gas (Sections 8.3 and 8.4). It also requires about 6% more heat exchange capacity, as determined from the enthalpies of the feed and cooled gases. 

Gas recycling requires additional heat exchange capacity, additional catalyst, and a blower. However, it is an efficient way of preventing first bed catalyst high-temperature degradation. 

Operation of the cesium catalyst at a much lower inlet temperature than the potassium-promoted catalyst achieved a sulfur dioxide conversion in the range 99.2-99.6%. This was comparable to a double-absorption plant but with a lower capital cost apart from increased heat exchange capacity and a slightly more expensive catalyst. It allows producers to use existing four-bed single-absorption units and meet environmental demands without the capital expense of a new plant. 

The operation of both designs is quite different. When opening the valves in the connecting lines the full heat exchanger capacity is available from the beginning while the heat exchanger of the SWR 1000 will start slowly from zero to full capacity. 

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