Abstract: An apparatus and method for the protection of a pipe containing an inflammable gas against back fire. The apparatus comprises a container partially filled with liquid extending along a given length of the container and at a give level, at least one gas feed pipe, and at least one horizontal inlet pipe, each immersed in the liquid and sealed at one end and receptive of gas at the other end from the feed pipe. Each inlet pipe has holes in its circumferential surface for the introduction of the gas into the liquid, with the number of holes and the dimensions thereof such that at the maximum gas volume flow rate, the outflow rate through the holes is at the most 40 m/sec and the rate in each gas feed pipe is at the most 20/sec. Additionally, each inlet pipe extends over only part of the length of the liquid in the container. A gas outlet nozzle is positioned above that part of the container where there is no pipe and a calming grid is disposed at the liquid level to subdue waves in the liquid.

Abstract: The invention relates to separately removing organic and inorganic impurities from exhaust gases so that the recovered materials are relatively pure and re-usable, using adsorption on carbon for selective removal of the organics and absorption in aqueous media for the inorganics. Carbon is first saturated with the same inorganics so that, when contacted with the exhaust gas, it removes only the organics. The residual gas, free of organics, upon absorption gives an inorganic solution of high purity. Steam regeneration of the carbon liberates the volatile organics. Systems are described using the two carbon beds in series, the second of which is undergoing inorganic presaturation while the first is removing the organics.

Abstract: Advantageously the absorption solution is glutaric acid buffered to a pH of about 3.5 to 6.5, the concentration of the glutaric acid is from about 40% up to 90% of the saturation concentration, its temperature is from about 20 to 25.degree. C, it has a concentration of heavy metal ions no more than about 10.sup.-6 mole/l, and to improve the separation of SO.sub.2 from the absorption solution steam is introduced into at least one separator in from about 0.01 to 0.1 kg/l of solution to be desorbed.

Abstract: Hydrogen sulfide in a gas is converted to sulfur by treatment with sulfur dioxide in the presence of a buffered organic polybasic acid with conversion of excess sulfur compounds in the gas to sulfur dioxide for recycle to the conversion.