High-pressure disintegration process

The latest technological developments in wheat starch production are the high-pressure disintegration (HD)53,94-97 and the Tricanter 97 processes. The HD process, which is based on a highly sheared batter and on centrifugal forces for separation, was jointly developed by the Technical University of Berlin and Westfalia Separator. 

Its use was first reported in 1985 by Meuser et al.98 for extracting starch from com. The HD process for commercial production of wheat starch and wheat gluten is used in many countries in Europe and in Australia, Canada, Mexico, India and Venezuela. 

The A-starch slurry from the centrifugal decanter is screened and then refined either with hydrocyclones or with separators and decanters. Purification and concentration of A-starch is accomplished in multistage hydrocyclones, or the A-starch slurry is separated into A and B fractions in a nozzle-type centrifuge and the A-starch fraction is finally refined in a centrifugal decanter. The B-starch stream is passed through vibrating screens and concentrated in a decanter. Pentosans and other solubles are concentrated and either dried or co-fermented with the B-starch for ethanol production. 

Two major advantages of the HD process are reduction in water consumption to as low as three parts per part of wheat flour, and a 10% increase in A-starch yield. In addition, this process is not as sensitive to flour quality as the other processes, and is also applicable for potato, bean, pea and com starch production. 

Properties of Wheat Starch and Wheat Starch Amylose and Amylopectin 

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The major hazard that can occur in the high-pressure polyethylene process is a runaway of the reactor and decomposition of ethylene as well as fires, explosion, and disintegration of high-pressure parts. Although the last incidents are well understood, the reasons for runaway and ethylene decomposition have been evaluated only recently. Experience over twenty years has shown that decomposition mostly takes place in the reactor and in the high-pressure separator, but decompositions have also been reported from ethylene-feed and product lines. 

Figure 10.2 Flow diagram of the high-pressure disintegration (HD) process. (Adapted from reference 53)...

Fig. 8.4 Structures of compacts from high-pressure agglomeration after processing equal feed materials (recrystallized KCI, Potash) at low (left, brittle disintegration) and elevated (right, plastic deformation) feed temperatures in identical roller presses with the same operating parameters. (For more information see text.).

In airless hydraulic) atomization the paint is forced through a slit nozzle of hard metal under high pressure (8-40 MPa). On account of the high degree of turbulence, the paint stream disintegrates immediately after leaving the fluid tip. A similar atomization process occurs in spray cans where the paint pressure is produced by the propellant gas. 

Increase (by a factor of 2-3) the drying rate Eliminate property (e.g., temperature) distribution within the dryer, which improves the product quality Lower gas and product temperatures during processing Handle sticky materials that form lumps or aggregates without mechanical mixing or disintegration Atomize most pumpable liquids without the need for an atomizer or high-pressure nozzles Reduce unit air consumption by 30%-40%... 

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