Vacuum systems steam supply

In the above example, 1 lb of initial steam should evaporate approximately 1 lb of water in each of the effects A, B and C. In practice however, the evaporation per pound of initial steam, even for a fixed number of effects operated in series, varies widely with conditions, and is best predicted by means of a heat balance.This brings us to the term heat economy. The heat economy of such a system must not be confused with the evaporative capacity of one of the effects. If operated with steam at 220 "F in the heating space and 26 in. vacuum in its vapor space, effect A will evaporate as much water (nearly) as all three effects costing nearly three times its much but it will require approximately three times as much steam and cooling water. The capacity of one or more effects in series is directly proportional to the difference between the condensing temperature of the steam supplied, and the temperature of the boiling solution in the last effect, but also to the overall coefficient of heat transfer from steam to solution. If these factors remain constant, the capacity of one effect is the same as a combination of three effects. 

Fig. 2.43. Schema of a steam-sterilizable closing mechanism for vials. The pressure plate (1), by which the stoppers are pushed into the vials is sterilized jointly with the chamber. The shaft (2) to which the pressure plate is connected, moves into the chamber during stoppering. It is not sterilized with the chamber. Therefore the shaft is sterilized in a separate chamber (3). This chamber can also be connected to the vacuum pumping system (4) as to the steam supply (5). Water condensing during the sterilization can be drained by (6). A special seal (7) can (by (8)) also be connected to steam or vacuum, and be sterilized (schematic drawing from information by AMSCO Finn-Aqua, D-50354 Hiirth).

The caustic feed (Stream 1), entering the second effect from the left, contains 35% NaOH and is at 90°C. A vacuum system, here in the form of a steam jet, maintains a low operating pressure. The condenser, not shown, normally is a barometric unit. With heat supplied by vapor from the first effect, the second effect produces 42% NaOH, which then goes to the steam-heated first effect. The first-effect product liquor (Stream 4) is 50% NaOH at 136 = C. 

In the industrial preparation of aniline, the iron is added gradually and less water is used.2 The yields obtained are practically quantitative about 110 kilograms of pure aniline from 100 kilograms of benzene. The aniline is vacuum distilled in batches of 10,000 to 30,000 kilograms, the heat being supplied by a system of steam coils inside the kettle. 

Fig. 1 Sterile dosage form processing equipment useful for clinical supply manufacture in the pilot plant. (A) Vial and ampule washer (Metromatic. Oyster Bay, NY). (B) Steam sterilizer (Amsco Finn-Aqua, Apex, NC). (C) Vial filler (TL Systems Corp., Minneapolis). (D)Lyophilizer (Edwards High Vacuum International, Tonawanda, NY). (E) Vial capper (The West Co., Phoenix-ville, PA).

Solvent can be removed from the marc by heating with heat supplied by the outside shell, injecting steam, or pulling a vacuum on the extractor. Solvent-free marc is dumped out the bottom of the extractor. Extractors capable of vacuum operation are available to handle 70-450 kg (150-1000 lbs) of raw material. Much larger capacity is available for nonvacuum systems, up to 6800 kg (15,000 lb) loads. 

The chemical plant consists of a single-effect vacuum evaporator system for regenerating the solution and liberating the sulfur dioxide. Indirect heat is supplied to the forced-circulation evaporator by using exhaust steam from the refinery. The vacuum is supplied by a liquid ring vacuum pump which also pumps the sulfur dioxide back into the front of the Claus plant. 

There are a number of other possible utihties which may be provided to a laboratory. Among these are natural gas, compressed air, distilled water, vacuum, steam, refrigerated brine, and other gases. In some instances, there are safety issues, such as limitations on the pressure available from a compressed air hne and the need to incorporate provisions for pressure relief, to ensure that personnel will not be injured by explosions due to excess pressure. Often the quahty of the air is more of a problem. The compressor supplying the system should be capable of supplying air which is clear of oil and moisture. Some facilities which have a large, pressurized liquid nitrogen tank at hand, use the vapors from the tank as a source of ultra clean compressed air to clean woik surfaces. 

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