Abstract: A vapor compression distillation apparatus and method are provided wherein scaling tendencies are eliminated. The raw feedwater has acid added to it in an amount sufficient to convert the carbonates and/or bicarbonates therein to carbon dioxide. The heated acidified feedwater is then deaerated to remove the carbon dioxide and other non-condensible gases. The deaerated water flows to the evaporator through a line having a valve therein controlled by the liquid level in the deaerator to maintain such level constant even though the tube side of the evaporator is being operated at a pressure less than that of the deaerator. This permits the evaporation to take place under a partial vacuum and at a boiling temperature of less than 212.degree. F. even though the deaerator is operated at atmospheric pressure. Vent steam from the evaporator is added to the deaerator to further preheat the feedwater, and as a sparging or stripping agent to aid in the elimination of carbon dioxide and other non-condensible gases.

Abstract: A vapor compression type distillation unit is provided for distilling brackish water or seawater wherein high heat transfer rates are achieved in a vertical shell and tube type vaporizer while avoiding carry-over normally resulting from excessive foaming and its entrainment of liquid droplets in the vapor. A pool of liquid is maintained at the lower end of the vaporizer to be fed into the tubes with the level of the liquid being relatively low so that most of the length of the tube is filled with a frothy mixture conducive to high heat transfer rates. The mixture of vapor and liquid discharged from the upper ends of the tubes is caused to flow laterally and then downwardly through a downtake passage communicating with the lower end of the vaporizer. A vapor outlet is provided intermediate the ends of the downtake passage in such a manner that the vapor must change its direction of flow, preferably substantially 180.degree.

Abstract: A vapor compression type distillation apparatus and method is provided for distilling brackish water or seawater wherein increased efficiency can be achieved by virtue of an arrangement and operation which maximizes the average effective temperature differential between steam being condensed and the water being vaporized. Thus a vertical shell and tube vaporizer is provided which includes an array of tubes which array has a width substantially greater than its depth. The liquid discharged from the upper ends of the tubes is caused to flow downwardly in a downtake passage into a body of water at the lower end of the vaporizer along substantially the entire width of the array. Feed water is fed into the body of water at the lower end of the vaporizer at one end of the array and blowdown is taken from such body at the other end of the array.