Refrigerated Condensers

If the solvent is volatile, there will be some loss with the vapor. This should be avoided if the solvent is expensive and/or environmentally harmful by using a condenser (refrigerated if necessary) on the vapor leaving the absorber. 

This cooling effect of the evaporation of water can be applied directly to the condenser refrigerant pipes in the evaporative condenser (Eigure 6.7). The mass flow of water over the condenser tubes must be enough to ensure wetting of the tube surface, and will be of the order of 80-160 times the quantity evaporated. The mass flow of air must be sufficient to carry away the water vapour formed, and a compromise must be reached with expected variations in ambient conditions. An average figure is 0.06 kg/ (s kW). 

Automatic gas purgers comprise a collection vessel for the gas mixture with an inhuilt cooling coil connected to the main suction, or with its own refrigeration system. Condensed refrigerant returns to the condenser, and any gas remaining in the vessel will he non-condensihle and can he vented hy an inverted bucket trap. 

Some assumptions must be made regarding the condenser coil performance, and this may have a AT of 14 K between the entering air and condensing refrigerant and subcooling the liquid 5 K, with suction gas entering the compressor with 6 K superheat. 

Now that the evaporator is cooler, we could increase the flow of warm process fluid to the evaporator. Thus, improving the efficiency of the condenser will increase the capacity of a refrigeration system to cool. This happens mainly by lowering the compressor discharge pressure rather than producing a colder condensed refrigerant. 

Most of the water at the bottom of IB, now enriched to 0.117 a/o deuterium, is converted to vapor in the reboiler and returned to IB, but around 12 percent is pumped ahead to the top of 2A. Vapor from the top of 2A is condensed in a condenser refrigerated with ammonia, to prevent loss of the now valuable water. This condenser is also vented to a steam qector, which maintains a pressure of 130 Ton. 

A light-hydrocarbon mixture is to be separated by distillation, as shown in Figure 9.29, into ethane-rich and propane-rich fractions. Based on the specifications given and use of the Soave-Redlich-Kwong equation for thermodynamic properties, use ASPEN PLUS with the RADFRAC distillation model to simulate the column operation. Using the results of the simulation, with Tq = 80°F, a condenser refrigerant temperature of 0°F, and a reboiler steam temperature of 250°F, calculate the... 

The characteristics of the process wastewaters from each pretreatment sub-group are shown in Table 3. Daily wastewater flows are characterized as intermittent because some major unit processes, e.g., cheese and butter making, are batch, and because milk processing equipment must be shut down daily for sanitizing to maintain rigid health standards. Relatively clean water may be a substantial portion of the total wastewater from a dairy plant. These waters are from condensers, refrigeration compressors, milk coolers, and air conditioning systems. 

Draining of condensed refrigerant from the condenser to the accumulator drum may be restricted due to piping hydraulics or mechanical blockage. (Once, a dead rat was found in the accumulator feed line.)... 

Refrigerant motor-driven compressor Refrigerant condenser Refrigerant letdown valve Evaporator Refrigerant receiver... 

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