Electric Dehydration Research Articles

ENERGY USE, COST, AND PRODUCT QUALITY IN PRESERVING VEGETABLES AT HOME BY CANNING, FREEZING, AND DEHYDRATION

ABSTRACTCarrots, zucchini, and summer squash were processed by canning, freezing, and dehydration according to procedures used in the home. Energy used was measured and the cost of preservation was calculated with the packaging and amortized equipment cost included. Reduced ascorbic acid and carotene contents were determined within a week after processing and after 6 months of storage. Sensory quality of the processed vegetables was evaluated in less than a month after processing. The vegetables were cooked with salt added for sensory evaluation. Freezing required the shortest processing time and resulted in products with the highest sensory quality, with ratings well above minimum acceptability, and the most ascorbic acid (assuming the canned liquor is not used) and carotene. More energy (electricity) was required to process and store vegetables by freezing than by canning or dehydrating with a commercially available electric dehydrator; however, the overall cost for freezing preservation was estimated to be as low as or lower than the cost for the other two preservation methods if the freezer could be kept full. With the freezer only half‐full freezing would cost more than canning or dehydration for a long term (> 6 months) storage. Canning used much less electric energy and was slightly cheaper in overall preservation cost than dehydrating with the electric dehydrator, and the canned products retained much more ascorbic acid and carotene than the dehydrated products. Nearly all ascorbic acid was lost during dehydration. The canned and dehydrated products were rated low in sensory quality, with ratings mostly below minimum acceptability.

The need for using electric dehydrators in crude treatment plants

The need for using electric dehydrators in crude treatment plants

Use of standard-frequency electric dehydrators in desalination plants at oil fields

Use of standard-frequency electric dehydrators in desalination plants at oil fields

Electrical dehydration of tar emulsions

Electrical dehydration of tar emulsions

The Electrical Dehydration of Cut Oil

Much crude oil, as produced from the well, carries varying amounts of water, which may be present as free water in globules sufficiently large to settleout, in time, if the fluid is allowed to stand, or as an emulsion formed bymyriads of minute water particles, each surrounded and entrapped by a film ofoil through which it cannot break under the action of gravity alone. Such anemulsified mixture of oil and water is commonly termed "cut oil." When such an emulsion is subjected, under proper conditions, to theinfluence of a high-potential alternating-current field, the minute waterparticles rupture the enveloping oil films and coalesce into larger waterdroplets this procedure continuing until all the water is freed into drops ofsuch size that they readily settle out. This action has been photographed bythe micro-moving-picture camera; under the microscope, the breaking-up of theemulsion, as described, is seen to be accomplished in a few seconds. The low power requirements of the process, from records of commercialplants, substantiate the theory that the action is that of a multitude ofelectrical condensers in series, rather than that of a number of conductingpaths. The minute water particles serve as the metallic elements, or plates, ofthe condensers and the separating oil acts as the dielectric. Such surfacecharges as the particles may have are removed, and the intervening oil isbroken, probably electrically by the voltage and mechanically by the attractiveforce between adjacent oppositely electrified particles. The principle of breaking up an emulsion under the influence of analternating electric field was discovered by F. G. Cottrell and Buckner Speed, through experiments conducted, at the University of California, which resultedin a plant being installed on the property of the Lucile Oil Co. in theCoalinga field, California, early in 1909. This plant was able to reduce 14-percent. emulsion to less than 2-per cent. with commercial success. AIME 070–58

Discussion on Electrical Dehydration of Crude Oil

Discussion on Electrical Dehydration of Crude Oil