Refrigerated condensation

Refrigerated condensation. Separation by condensation relies on differences in volatility between the condensing components. Refrigeration or a combination of high pressure and refrigeration is needed. 

Can the loss of useful material in the purge be avoided or reduced by additional separation on the purge The roles of refrigerated condensation, membranes, etc. in this respect have already been discussed. 

Improved and redesigned rotors of modem compressors save considerable power. The ethylene fractionator and the propylene refrigeration condensers can be replaced with extended surface tube bundles instead of conventional tube bundles. 

For the actual systems, compressor work will be higher than for ideal for the isentropic efficiency and other losses. In the case of hermetic or accessible compressors where an elec trical motor is cooled by the refrigerant, condenser capacity should be ... 

Kiihl-anlage, /. cooling plant, refrigerating plant, -apparat, m. cooling apparatus cooler refrigerator condenser, -bottich, m. cooling tub, cooler. 

A fluid-bed reactor is used at moderate pressures at approximately 450°C. The reactor effluent, containing chlorinated organics, water, a small amount of HCl, carbon dioxide, and other impurities, is condensed in a water-cooled graphite exchanger, cooled in a refrigerated condenser, and then scrubbed. Separation of perchlor from the trichlor occurs by successive distillation. Figure 7-6 shows the PPG process. 

Figure 7-6. The PPG Industries Inc. Chloroethylene process for producing perchloro- and trichloroethylene (1) reactor, (2) graphite exchanger, (3) refrigerated condenser, (4) scrubber, (5) phase separation of perchlor from trichlor, (6, 7) azeotropic distillation, (8) distillation train, (9-11) crude trichlor separation—purification, (10-16) crude perchlor separation—purification.

Many suppliers now offer water treatment for use in refrigeration condenser circuits, and the merits of different methods need to be assessed before making a choice. The reader is referred to specialist works on the subject [10, 19, 21]. 

Refrigerant condenser coils of heat pump or heat reclaim systems Figure 24.1 shows the sensible heating of air. 

Since the end product is to be useful heat, there is an opportunity with heat pump compressors to use a drive motor which will contribute to this. The internal combustion engine is used for some drives, adding its radiator heat to the load, and at a higher temperature than the refrigerant condenser can provide. As the installation is static, and required to run for comparatively long times without attention, the ideal fuel is natural gas. Compressor and drive assemblies must be robust to withstand the extra vibration, and should be separate from the rest of the circuit. Engine combustion air intakes must be from outside the plantroom and possible refrigerant leaks. Steam drives have also been used. 

If the feed is partially vaporized, the vapor flow below the feed will be lower than the top of the column. For above ambient temperature separations, the cost of operating the distillation will be dominated by the heat load in the reboiler and the vapor flow in the bottom of the column. For below ambient temperature separations, the cost of operating the column will be dominated by the cost of operating the refrigerated condenser and hence the vapor flow in the top of the column. If constant molar overflow is assumed, the vapor flow in the bottom of the column V is related to the vapor flow in the top of the column by... 

Example 24.4 Following Example 24.1, calculate the target for refrigeration power for a cooling duty of 3 MW with an evaporator temperature of — 30°C and refrigeration condenser temperature of 40°C using... 

Uses Manufacture of acrylonitrile, hydrazine hydrate, hydrogen cyanide, nitric acid, sodium carbonate, urethane, explosives, synthetic fibers, fertilizers refrigerant condensation catalyst dyeing neutralizing agent synthetic fibers latex preservative fuel cells, rocket fuel nitrocellulose nitroparaffins ethylenediamine, melamine sulfite cooking liquors developing diazo films yeast nutrient. 

The vapor is next cooled and condensed in the refrigerant condenser. Typically, 75 to 80 percent of the condenser heat duty is the... 

Lowering the compressor discharge pressure can be achieved by changing to cooler water to the refrigerant condenser. But how does this affect the horsepower load or electrical power demand on the compressor s driver Well, it depends. It depends on how much the refrigerant vapor flow increases, as the compressor discharge pressure is reduced. 

A closed-loop refrigerant condenser ought to be one of the cleanest services in a process plant. Even seal- or lube-oil leaks affect the evaporator efficiency, rather than the condenser. I have measured rather high [e.g., 140 Btu/[(h)(ft2)(°F)] heat-transfer coefficients in such condensers, even after that condenser has been in service for several years since its last cleaning. 

The mechanical pressure rating of the compressor case or the refrigerant condenser shell. 

The simplest way to lower the compressor discharge pressure is to reduce the cooling-water temperature to the condenser. One neat trick I have used is to use the cooling-tower makeup water on a once-through basis, to the refrigerant condensers. This supply of water is almost always 10 to 20°F cooler than the cooling-water supply. 

Figure 3.12. Fractionator for separating ethylene and ethane with a refrigerated condenser. FC on feed, reflux, and steam supply. LC on bottom product and refrigerant vapor. Pressure control PC on overhead vapor product.

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