Moisture removal efficiency

Chung, T.W., Predictions of moisture removal efficiencies for packed-bed dehumidification systems. Gas Sep. Purif., 8(4), 265-268(1994). 

However, some semiaromatic nylons can give problems as a result of the high melt viscosity. A process for produciag polymers of hexamethylenediamine, adipic acid, terephthaUc acid, and isophthaUc acid has been developed, which iavolves vaporising the salt mixture ia a high temperature flash reactor followed by molecular weight iacrease ia a twia-screw extmder with efficient moisture removal (17). 

Any process takes a certain amount of time and the length of the residence time often dictates the occasions when particular equipment or technology can be used. On the other hand, in almost all chemical unit processes the driving forces vary from time to time, and therefore time has the nature of non-equivalence, i.e., an equal time interval yields different, even greatly different, results for the early and later stages of a process. The result mentioned here means the processing amount accomplished, such as the increments of reaction conversion, absorption efficiency, moisture removal etc. Normally, these parameters vary as parabolic curves with time. Because of the nature of the non-equivalence of time, in addition to the mean residence time, the residence time distribution (RTD) affects the performance of equipment, and thus receives common attention. 

Vacuum and pressure laboratory filtration assemblies are shown in Figure 11.7. Mild agitation with air sometimes may be preferable to the mechanical stirrer shown, but it is important that any agglomerates of particles be kept merely in suspension and not broken up. The test record sheet of Figure 11.8 shows the kind of data that normally are of interest. Besides measurements of filtrate and cake amounts as functions of time and pressure, it is desirable to test washing rates and efficiencies and rates of moisture removal with air blowing. Typical data of these kinds are shown in Figure 11.3. Detailed laboratory procedures are explained by Bosley (1977) and Dahlstrom and Silverblatt (1977). Test and scale-up procedures for all kinds of SLS equipment are treated in the book edited by Purchas (1977). 

Since a large portion of a feedstock s equivalent energy content can be expended for drying, there is a balance between the cost of moisture removal, the incremental improvement in efficiency on conversion, and the advantages of handling drier feedstock. The key biomass property that should obviously be examined, in addition to conversion process requirements, is the moisture content of the fresh biomass, the methods available for its partial or total removal, and the effects, if any, on the properties of the remaining biomass. The moisture content of biomass is as variable as the multitude of biomass species available as potential feedstocks. 

Because of the very low moisture content of the prepared soil feed, an insufficient volume of aqueous condensate was collected from the tests to perform analysis or treatability tests. A vent gas sample was taken, but no valid analytical results were generated because of delays in sample processing. However, analysis of the carbon used in the emission control adsorbers enabled some evaluation of scrubber performance and process emission potential. Onlv the front (upstream) portion of carbon from one of the tests showed detectable levels of any CDD or CDF. Mo HO constituents were detected in the downstream portion of carbon. Calculated scrubber removal efficiencies exceeded 99.9 percent for CDD, CDF, 2,4-D, and 2,4,5-T. Vent gas volume was about 0.05 m /minute for all tests. 

Haas, M.J. K.M. Scott. Moisture removal substantially improves the efficiency of in situ biodiesel production from soybeans./. Am. Oil Chem. Soc. 2007, 84, 197—204. 

The high heat transfer efficiency makes the unit, using sand as a particulate, suitable for heat treatment applications such as pasteurization, precooking, insect eradication, and other applications in which moisture removal is not apriority. With zeolites as the transfer medium, moisture removal rates double, thus bringing drying efficiency up to the standards. 

Process air temperature. Different materials require different drying temperatures for efficient moisture removal. Drying temperatures vary widely among resins, with nylon requiring only 140 to 160° F, while PET may require temperatures as high as 350°F. 

Initial and final moisture content of the solid. This gives total amount of water vapour to be removed per batch. The efficiency of drying can be determined by amormt of moisture removed per kilogram of steam consumed. (Amount of steam condensate shoirld be measured for this purpose.)... 

Once a feed strategy is identified, appropriate screw configuration and barrel design for commercial extrusion must be identified (Schenck ef al. 2011). As a process is scaled from pilot to commercial scale, often a need for more efficient moisture removal is identified. This requires optimal placement and design of melt seal sections near the feed zone to prevent premature plasticization of the feedstock by water vapor. In addition, vents must be placed accordingly along the extruder barrel with... 

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