Auxiliary condenser

J0. A Cj Splitter column uses vapor reoompression. Bei use of the low temperature required to stay below the critical temperatures of ethylene and ethane, the auxiliary condenser must be cooled by a propane refrigeration system. 

Two distillation columns are heat-inicgraled as shown in the sketch below. The first column has an auxiliary condenser to take any excess vapor that the second column does not need. The second column has an auxiliary reboiler that provides additional heat if required. 

Centrifugal air pumps, lately introduced, use the centrifugal action of water to entrain the air. They are simple in operation, though of low efl ciency from a power standpoint. The Parsons Vacuum Augmenter uses a steam jet to draw out the air which is then passed over the coils of a small auxiliary condenser. The condensed steam is pumped out in the usual way, but by a pump which need not maintain the high vacuum existing in the condenser, and may there-ore be small. 

The pressure in the first column is controlled by vapor flow rate to the auxiliary condenser. A low-pressure override pinches the vapor valve to the second column leboi ter. 

J = Evaporator with electric heater, llj= Column for separating SiFj and HF, III — Separation tube and packing, IF = Double condenser for BF, F = Feed ve.ssel for liquid BB j, with electric heater. VI = Ethylene condenser, 7II = Rubber bladder for pressure regulation, VIII — Storage vessel for liquid nir, IX = Auxiliary condenser... 

Now, we want to look at the dynamics of this complex flowsheet. There are three major issues that must be addressed in designing a control system for a heat-integrated column process that is operating under neat conditions. Auxiliary reboUers or auxiliary condensers are not used to balance the vapor boUup needed at the base of the low-pressure column with vapor condensation needed at the top of the high-pressure column. 

Auxiliary condenser needs to handle an increase in methanol in feed. 

FIGURE 11.5 Top view of an industrial freeze dryer of 60-m shelf area with auxiliary condenser (Criofarma model C1200-20) 1, drying chamber with double full doors 2, principal ice condenser chamber 3, auxiliary ice condenser chamber 4, product support shelf. (Model C1200-20 courtesy Criofarma.)... 

Auxiliary condensers and reboilers are those installed in parallel with normal condensers and reboilen for startup or peak load purposes. 

Recovery and purification subsystems for krypton and xenon are shown in Figs. 6.35 and 6.36, respectively. An auxiliary condenser-reboiler is used to evaporate some of the oxygen from the liquid oxygen-krypton-xenon stream removed from the main condenser-reboiler. Nitrogen gas from the lower column furnishes the heat for evaporation. To minimize explosion hazards, the presence of all hydrocarbons, especially acetylene ice, must be avoided in the oxygen mixture. The oxygen-krypton-xenon mixture from the condenser-reboiler is sent to a small stripping column where the krypton and xenon are further concentrated. 

Space needs to be provided for the auxiliaries, including the lube oil and seal systems, lube oil cooler, intercoolers, and pulsation dampeners. A control panel or console is usually provided as part of the local console. This panel contains instmments that provide the necessary information for start-up and shutdown, and should also include warning and trouble lights. Access must be provided for motor repair and ultimate replacement needs to be considered. If a steam turbine is used, a surface condenser is probably required with a vacuum system to increase the efficiency. AH these additional systems need to be considered in the layout and spacing. In addition, room for pulsation dampeners required between stages has to be included. Aftercoolers may also be required with knockout dmms. Reference 8 describes the requirements of compressor layouts and provides many useful piping hints. 

The noncondensable gases eventually reach the condenser (unless vented from an effect above atmospheric pressure to the atmosphere or to auxiliary vent condensers). These gases will be supplemented by air dissolved in the condenser water and by carbon dioxide given off on decomposition of bicarbonates in the water if a barometric condenser is used. These gases may be removed by the use of a water-jet-type condenser but are usually removed by a separate vacuum pump. 

Stokes Vacuum, Inc. Prices include shell, 50-lh/in -gaiige jacket, agitator, drive, and motor auxiliary dust collectors, condensers. iLoading with product level on or around the agitator shaft. 

Figure 16-49 [Engineering Data Book, 10th ed., Gas Processors Slippers Association, Tulsa, 1988, Sec. 20, p. 22] depicts the flow scheme for a typical two-bed TSA dryer system showing the auxiliary equipment associated with regeneration. Some of the diy product gas is externally heated and used couutercurreutly to heat and desorb water from the adsorber not currently drying feed. The wet, spent regeneration gas is cooled the water is condensed out and the gas is recycled to feed for recovery.

Enantioselective aldoi condensation by means of a chiral auxiliary and boron enolates... 

Thermal power plant auxiliaries such as flow control of primary air fan, ID fan and forced-draught fans, boiler feed pumps circulating water pumps and condensate pumps, coal handling plant (e.g. ball mill, wagon tippler, and stacker reclaimer)... 

Condensate from contact units cannot be reused and may constitute a waste disposal problem. Surface condensers can be used to recover valuable condensate. Surface condensers must be equipped with more auxiliary equipment and generally require a greater degree of maintenance. 

Condensers should be designed to provide a realistic amount of excess auxiliary exhaust steam with reasonable velocity steam inlets and exhausts. Also, steam baffles should be slanted away from condenser bracing and other critical areas. 

In cycle D4 [15, since the fuel is burnt with pure oxygen, the exhaust gases contain CO2 and H2O almost exclusively (Fig. 8.21). Cooling the exhaust below the dew point enables the water to condense and the resulting CO2 stream is obtained without the need for chemical absorption. The exjjensive auxiliary plant involved in direct removal of the CO2 is not needed, but of course there is now the additional expense of an air separation plant to provide the pure oxygen for combustion. 

Condenser Controls. .Miscellaneous (Condensing System). Circulating Water. System. Condensate Sysrem. . Pumpa, Piping and Valves. .Low/Tnter. Press- Heater/Oeaerators 3350-3352. .Polishers/Chemical Addle Ion 3360-3399. .Miscellaneous (Condensate System) 3901-3999. Feedwater System 3501-3509. Heater Drain Systems 3520-3529. Entractlon Steam. Electrical. Auxiliary Systems. .Service Water (Open System)... 

One of the most common methods for introducing asymmetry into a Pictet-Spengler condensation reaction is to append a non-racemic auxiliary onto the indole amine or... 

Vor-norm, /, tentative standard, -ozydation, /. previous oxidation, -polieren, n. roughpolishing, first polishing, -posten, m. out post, -praparation,/. previous or preliminary preparation or treatment, -probe, /. preliminary test, -produkt, n. initial (or primary) product crude product, specif, crude benzol intermediate, -produktkiihler, m. (Coal Tar) crude benzol condenser, -priifung, /. previous or preliminary examination, -pumpe, /. auxiliary pump (as for vacuum) (Brewing) circulator, wort pump. 

In general, the number of boosters determines the operational flexibility of the unit with respect to the refrigeration load. A single booster unit operates continuously, regardless of load. A two booster unit can operate at 50% load by shutting off one unit at lower load levels it uses a pressure controller on the steam actuated by the condenser pressure. Because jets are not usually very flexible with respect to steam consumption and vacuum, load control may be in increments as compared to continuous variation. If a 100-ton unit is expected to operate an appreciable portion of the time at 25% of load, it may prove economical to install a four-booster unit and to operate only one for this period. Auxiliary ejectors remove uncondensed water vapor and air from the main condenser. 

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