Moisture recovery

Moisture recovery Measures taken to prevent the moisture present in the air from leaving the treated space. 

The measurements first reveal an increase in the water level, which can be attributed to moisture transfer from the stopper into the product. The decrease observed subsequently could be due to water expulsion as a result of some product transformation (crystallization of sugar within the substrate, for example). The water would then be adsorbed by the stopper. As a matter of fact, it is well known that the capacity of stoppers to adsorb water depends on their composition [13-15]. Finally, in the third stage, transfer by diffusion through the stopper could account for the slow moisture recovery in each sample. 

Such a moisture recovery translates into an increase in water activity (a ). However, as shown by Figure 7, the rate of most chemical and biochemical reactions increases as increases [4,18]. In consequence of these variations, phenomena such as drop in infectivity titers and/or alteration of the substrate may be observed during storage of freeze-dried products. 

The final balanced strain recovery (R ) is defined as the maximum strain recovery (R,, ) the strain recovery onset time (t ) is conditioning time at which the strain recovery is 10% the strain recovery time (y is the conditiotring time at which the strain recovery is 50% R and the strain recovery end time (t ) is the conditioning time at which the strain recovery is the 90% The time length (t = t - t ) is also used to characterize the moisture recovery speed, i.e. when t is shorter, the recovery speed is quicker. 

The precipitated cellulose acetate is filtered from the dilute (25—36%) acetic acid. The acetic acid and salts remaining from the sulfuric acid neutrali2ation are removed by washing. The wet polymer is typically dried to a moisture content of 1—5%. The dilute acetic acid obtained from the washing and precipitation steps caimot be used in other stages of the process. Its efficient recovery and recycle are an economic necessity. 

Among the bast textile fibers, the density is close to 1.5 g/cm, or that of cellulose itself, and they are denser than polyester, as shown iu Table 5. Moisture regain (absorbency) is highest iu jute at 14%, whereas that of polyester is below 1%. The bast fibers are typically low iu elongation and recovery from stretch. Ramie fiber has a particularly high fiber length/width ratio. 

Separation Efficiency. Similarly to other unit operations in chemical engineering, filtration is never complete. Some soflds may leave in the hquid stream, and some Hquid will be entrained with the separated soHds. As emphasis on the separation efficiency of soHds or Hquid varies with application, the two are usually measured separately. Separation of solids is measured by total or fractional recovery, ie, how much of the incoming solids is coUected by the filter. Separation of Hquid usually is measured in how much of it has been left in the filtration cake for a surface filter, ie, moisture content, or in the concentrated slurry for a filter-thickener, ie, solids concentration. 

The products of reaction are pumped to a filter press for separation into a sodium sulfate solution and a filter cake having a low moisture content. The filter cake is then ready to be processed for the recovery of lead. The filtrate from the process contains an excess of sodium carbonate, and can be neutralized using the sulfuric acid drained from the batteries. 

Sheet Drying. At a water content of ca 1.2—1.9 parts of water per part of fiber, additional water removal by mechanical means is not feasible and evaporative drying must be employed. This is at best an efficient but cosdy process and often is the production botdeneck of papermaking. The dryer section most commonly consists of a series of steam-heated cylinders. Alternate sides of the wet paper are exposed to the hot surface as the sheet passes from cylinder to cylinder. In most cases, except for heavy board, the sheet is held closely against the surface of the dryers by fabrics of carefuUy controUed permeabiHty to steam and air. Heat is transferred from the hot cylinder to the wet sheet, and water evaporates. The water vapor is removed by way of elaborate air systems. Most dryer sections are covered with hoods for coUection and handling of the air, and heat recovery is practiced in cold climates. The final moisture content of the dry sheet usually is 4—10 wt %. 

In this process the addition of water vapor to the sweep stream can be controlled so that the water activity of the gas phase equals that of the beverage. When this occurs, there is no transport of water across the membrane. The water content of both the beverage feed and the sweep stream is kept constant. These conditions must be maintained for optimum alcohol reduction. The pervaporation system controls the feed, membrane, airstream moisture level, and ethanol recovery functions. An operational system has been developed (13). 

Vapors (from drying) are removed at the feed end of the dtyer to the atmosphere through a natural-draft stack and settling chamber or wet scrubber. When employed in simple drying operations with 3.5 X 10 to 10 X 10 Pa steam, draft is controlled by a damper to admit only sufficient outside air to sweep moisture from the cylinder, discharging the air at 340 to 365 K and 80 to 90 percent saturation. In this way, shell gas velocities and dusting are minimized. When used for solvent recovery or other processes requiring a sealed system, sweep gas is recirculated throu a scrubber-gas cooler and blower. 

In ordinaiy heating and coohng operations, during which there is no moisture pickup, continuous recirculation of the conveying gas is frequently employed. Also, solvent-recovery operations employing continuously recirculated inert gas with intercondensers and gas reheaters are carried out in pneumatic conveyors. 

Nitrobenzenesulfenyl chloride (NPS-CI) [7669-54-7] M 189.6, m 73-74.5", 74.5-75", 74-76". Recrystd from CCI4 (2mL/g), filter off the soln at 5° (recovery 75%). Also recrystd from pet ether (b 40-60°), dried rapidly at 50° and stored in a brown glass bottle, sealed well and stored away from moisture. [Hubacher Org Synth Coll Vol II 455 7943 Ito et al. Chem Pharm Bull (Jpn) 26 296 1978.]... 

Natural gas from MESA s wells flows into a gathering system where pressure is increased to 7 bar (100 psig). Multiple booster stations raise it to 34 bar (500 psig) before gas enters the plant for separation. When gas enters the LNG recovery unit, its pressure must be raised again to 66 bar (950 psig). It is then subjected to a molecular sieve process for moisture removal. A series of heat exchangers lowers the temperature to -34°C (-30°E). 

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