Improvements in or relating to the treatment of whale gluewater

摘要

PICT:0687513/III/1 Whale gluewater is treated to recover suspended solids, suspended oil and a processed stable gluewater of value as an animal food, by adding thereto an acidic material in amount sufficient to reduce the pH of the gluewater to within the range 4 to 5 while maintaining the temperature of the gluewater above 180 DEG F. but below boiling, holding the treated gluewater static for a period of at least 15 minutes, and thereafter separating the undissolved solids and the liberated oil from the gluewater. The pH range is preferably 4 to 4.5, such as 4.2. The acidic material is preferably sulphuric acid, but may be aluminium sulphate, any of the alums, ferric chloride or tannic acid. The gluewater from the time of its production through the time of pH adjustment is preferably kept at a temperature above 180 DEG F. and such temperature is preferably continued during the separation of solids and oil. The holding period is preferably at least 30 minutes. The final treated gluewater is subjected to vacuum evaporation to produce a concentrated product, such as a product having a soluble solid content of between 50 and 60 per cent by weight. The separations may be made by any suitable separation devices, mainly by various types of centrifuges, particularly a continuous sludge-discharge, horizontal type centrifuge for the removal of the solids and a continuous, three-phase nozzle-discharge type centrifuge for the removal of the oil. In a suitable plant, the hot gluewater, obtained from whale parts by usual methods, is pumped through conduit 11 to one of a number of acidulation tanks 10 to which the required amount of acidic material is fed continuously into admixture therewith through a conduit 15 and drip tank 16. After the tank is filled and the pH adjusted the tank is kept static at at least 180 DEG F. for the specified time. The hot mixture from the tank 10 is then passed into a continuous sludge-discharge, horizontal-type centrifuge 20 from which the solids are discharged into a cart 23 and the liquid component into a tank 24. From the latter the liquid is pumped through a heater 27 into a feed tank 28 supplying a centrifuge 30 suitable for separating the oil from the aqueous gluewater, such as described above. The heater 27 preferably raises the temperature of the gluewater above 200 DEG F., e.g. 210 DEG F. The stabilized gluewater discharged from the centrifuge 30 is pumped into a storage tank 34, from which it may be supplied to a vacuum evaporator 35. The concentrated product is stored in a tank 43. In a modified plant, the oil is removed prior to the solids by interchanging the positions of the centrifuges 20 and 30 together with their appurtenances. Specification 543,508, [Group II], is referred to.