Target cooling

Figure 24.21 Targeting cooling water flowrate in retrofit. (From Kim J-K and Smith R, 2001, Chem Eng Sci, 56 3641, reproduced...

Due to the high temperature in the surroundings of the Knudsen cell some additional units are installed. There is a water jacket around the heating assembly and a target cooled by liquid nitrogen to condense the effusion beam escaping from the Knudsen cell. 

Where the cold composite curve extends beyond the start of the hot composite curve in Fig. 6.5a, heat recovery is not possible, and the cold composite curve must be supplied with an external hot utility such as steam. This represents the target for hot utility (Q niin)- For this problem, with ATn,in = 10°C, Qnmin 7.5 MW. Where the hot composite curve extends beyond the start of the cold composite curve in Fig. 6.5a, heat recovery is again not possible, and the hot composite curve must be supplied with an external cold utility such as cooling water. This represents the target for cold utility (Qcmin)- For this problem, with AT in = 10°C, Qcmm = 10-0 MW. 

After maximizing heat recovery in the heat exchanger network, those heating duties and cooling duties not serviced by heat recovery must be provided by external utilities. The outer-most layer of the onion model is now being addressed, but still dealing with targets. 

Unlike for synchrotron radiation, the maximum iatensity of x-rays from an x-ray tube is limited by how fast heat can be removed from the target to prevent its melting. In a conventional sealed tube, the target is stationary, relatively small, and must be continually cooled with water. In a rotating anode tube, the target is larger and is continually rotated so that the heat can be distributed over a larger surface. With such a tube the amount of heat, and hence. 

After dewatering the cmmb it is fed to the drying process which is usually carried out in a continuous tunnel dryer. The cmmb is spread on a perforated stainless steel bed through which hot air is passed to evaporate the remaining water. Typically, in the first portion of the dryer, air at 110—140°C is used, with lower temperatures being used as the product approaches dryness. A typical target for final moisture content is 0.5% or less. At the exit of the dryer the product is cooled and conveyed to a baler which shapes it into bales for packaging and shipment. 

Cool (with agitation) to specified target temperature. The process state is Agitate with cooling. ... 

Figure 11-69 describes a typical central system. Either water or direct-expansion refrigerant coils or air washers may be used for cooling. Steam or hot-water coils are available for heating. Humidification may be provided by target-type water nozzles, pan humidifiers, air washers, or sprayed coils. Air cleaning is usually provided by cleanable or throwaway filters. Central-station air-conditioning units in capacities up to about 50,000 cu ft/min are available in prefabricated units. 

Ejfect of Gas Saturation in Scrubbing If hot unsaturated gas is introduced into a wet scrubber, spray particles will evaporate to cool and saturate the gas. The evaporating liquid molecules moving away from the target droplets will repel particles which might collide with them. This results in the forces of diffusiophoresis opposing particle... 

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