Cake washing free liquid

If the cake is washed with solnte-free liquid, percent remaining is readily calculated by dividing the solute concentration in the hqnid remaining in the washed cake by the solute concentration in the liquid in the original feed. 

In a 2-1. three-necked, round-bottomed flask fitted with a mechanical stirrer and two reflux condensers are placed 68 g. (0.68 mole) of succinic anhydride (Org. Syn. 12, 66) and 350 g. (4.5 moles) of dry, thiophene-free benzene (Note i). The stirrer is started and 200 g. (1.5 moles) of powdered, anhydrous aluminum chloride is added all at once. Hydrogen chloride is evolved and the mixture becomes hot (Note 2). It is heated in an oil bath and refluxed, with continued stirring, for half an hour (Note 3). The flask is then surrounded by cold water, and 300 cc. of water is slowly added from a dropping fimnel inserted in the top of one of the condensers. The excess benzene is removed by steam distillation, and the hot solution is at once poured into a 2-1. beaker. After the mixture is cold the liquid is decanted from the precipitated solid and acidified with concentrated hydrochloric acid (about 20 cJs is required) 5 to 15 g. of benzoylpro-pionic acid separates and is filtered off (Note 4). The residual suspension in tl e beaker is. boiled for five hours with 1500 cc. of water containing 360 g. of commercial soda ash the resulting solution is filtered with suction, the filter cake washed with hot water, and the filtrate acidified with concentrated hydrochloric acid (about 300 cc.). The precipitated benzoylpropionic acid is filtered and washed with hot water after dr3dng for a day it weighs 95-100 g. (77-82 per cent of the theoretical amount) and... 

We will briefly consider now the step of cake washing. This step is undertaken to recover the solutes left in the solution trapped in the cake mass. As the wash liquid displaces this trapped solution, the latter goes through the filter medium and is recovered in the filtrate inside the drum. Therefore, washing enhances the recovery of soluble fermentation products left in the liquid in the cake mass in the case of a fermentation broth. Since the wash liquid is suspension-free as well as solute-free, the cake filtration characteristics are unlikely to be altered. Hence, the filtration rate during washing should correspond to the filtration rate existing at the location where the drum came out of the suspension ... 

The ether solution of nitrourethane is filtered into a 4-1. flask or beaker and is diluted to 3 1. with anhydrous alcohol-free ether. The solution is then saturated with dry ammonia gas or treated with an excess of liquid ammonia, thereby precipitating ammonium nitrourethane. The product is filtered on a large Buchner funnel, washed with a small quantity of alcohol-free ether, f and dried by drawing air through the filter cake. Theoretical yield 170 g. actual yield 80 to 95 g. (47 to 55 per cent of theory). 

Amygdalin is present in bitter almonds, the seeds of Primus dulcis var. amara (DC.) Buchheim, and ripe apricot kernels, Prunus armeniaca L. (Rosaceae). The press cake, which remains after removal of the fatty oils, is macerated with water and left to stand for several hours, after which the essential oil is separated by steam distillation. The crude oil contains 2-4% hydrogen cyanide, which is removed by washing with alkaline solutions of iron(II) salts. Subsequent redistillation yields an oil free from hydrogen cyanide. It is a colorless to slightly yellow liquid with an intense, almond-like, cherry aroma and a slightly astringent, mild taste. 

There are three different preparations of yeast for bakers, on the market compressed yeast, dry yeast, and liquid yeast. Compressed yeast is mads from distillers wort. After the yeast has been collected from the wort, it is thoroughly washed, and then passed through wire and silk sieves to free it from foreign materials. After this cleaning process the yeast is pressed, cut into cakes, and wrapped in tin foil. Compressed yeast cakes are liable to start decomposition unless kept in a cool place. 

Removal of solids from a solution which contains the product as a solute. The solids represent the contaminant or carry it adsorbed on the smface (e.g. heavy metals). The aim is to thicken the solids into the wash liquid, as free as possible of the solute (i.e. with a minimum loss of the product). The system overflow contains the solute at a concentration only a little lower than that in the system feed. The process essentially removes the solution from the solids in a similar way as a cake filtration process, except it can do this for fine, difficult-to-filter solids and without exposure to air or to any filter medium, in a completely enclosed pipework free of moving parts (except for the pumps). This process is gaining favour in the chemical industry and it can be driven by high pressure at the front of the washing train—see the next section. 

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