Abstract: Reconcentration of moist glycol, which has been used to dry natural gas, by heating the moist glycol with flue gas from a reboiler and by thereafter stripping water from the moist glycol with the dried flue gas or with a hydrocarbon gas by-product of the natural gas being dried.

Abstract: To remove salts from a solution containing the salts, hot air is injected downwards into the solution in a concentrator, and the solution is concentrated by direct contact with the hot air, thereby enhancing an evaporation efficiency in the concentrator and preventing scale deposition in the concentrator and piping system. The solution is forcedly cooled in a crystallizer by direct contact with cool air, thereby making crystals grow in the solution within a short time. The solution and air are circulated in a closed cycle, thereby preventing a secondary environmental pollution.

Abstract: Wet process phosphoric acid is heated, preferably in carbon apparatus, by passing alternating current through the acid, to concentrations above 80% P.sub.2 O.sub.5 and preferably temperatures above 500.degree. C. to remove sulphate and fluoride and convert organic and basic impurities into a filterable precipitate: the acid is separated from the precipitate to provide a high purity crystallizable product.

Abstract: The column employs a head section with a counterflow column, a bottom section with a counterflow column and a plurality of reaction stages for stripping metal salts via steam from ammoniacal solutions or suspensions. Each reaction stage has a floor, a pipe defining a laterally confined chamber, an outlet and a valve in the outlet to control the discharge of liquid. At least one steam line communicates the upper end of each stage with the pipe in the next uppermost stage. Incrustation of the column by the stripped salts is reduced by the high velocity of flow in the bubble bed in each stage.

Abstract: Dilute solutions of corrosive products, such as sulphuric or phosphoric acid, are concentrated by pre-concentrating the dilute solution and then introducing the pre-concentrated solution into a tunnel in which it flows in a thin layer over successive cascades while being heated, preferably by indirect radiant heating. An installation for carrying out the process is also described.

Abstract: An evaporator-condenser unit is disclosed which includes an elongated enclosed chamber into which hot gases are injected to form a cyclonic stream therein. The hot gases impinge and pass around a substantial plurality of tubes containing relatively cool sanitary liquid waste. Condensation thereby forms on the tubes and is blown by the cyclonic action of the hot gas stream to the outer periphery of the cyclonic chamber where the condensation is collected and conveyed away from the chamber. At the same time, the heat from the hot gases is transferred to the liquid sanitary waste which is converted into steam in a steam expansion chest at the top of the cyclonic chamber. The steam is compressed and injected back into the hot gas stream flowing into the cyclonic chamber. The steam is then condensed on the tubes and conveyed away for appropriate utilization.