Showing papers on "Wet oxidation published in 1977"

Process for the wet oxidation of organic substances

Abstract: of the Disclosure A process has been developed for the oxidation of organic substances, dissolved or dispersed in an aqueous system, with a gas containing molecular oxygen at elevated temperature and under elevated pressure chiefly to carbon dioxide and water, with subsequent phase separation of the reaction mixture into a gaseous phase substantially containing inert gas, carbon dioxide, steam and organic constituents and a liquid phase substantially containing water, characterized in that the pressure is adjusted, at the given temperature, so that by evaporation of water from the aqueous system, more steam than the exotherm-icity of the oxidation reaction gives rise to,goes into the gaseous phase, which is fed to a heat exchanger in which the amount of heat required to maintain the oxidation temperature is completely or partially transferred to a mixture of water and a gas containing molecular oxygen, which mixture flows in on the other side of the heat exchanger and is subsequently fed to the reactor. A particular advantage of the process of the invention is that, in addition to the oxidation of organic substances, it is possible to fed inorganic constituents, after the oxidative degradation of the organic substances, to a re-use or recovery process.

The low-temperature oxidation of calcium by water vapor

Abstract: The oxidation kinetics of calcium in water vapor have been studied over the temperature range 25–300°C. There is a change in the form of the oxidation kinetics with temperature, from essentially linear at temperatures below 150°C to logarithmic at 300°C. This is coupled with a change in the manner of growth of the oxide layer as well as the chemical composition of the reaction product. In addition, the oxidation rate decreases with temperature, reaching a minimum at about 150°C. At temperatures below 150°C oxidation appears to be a result of the formation of cracks or fissures in the oxide film. Above 150°C no single oxidation mechanism can be deduced.

Process for the purification of waste water

Abstract: PROCESS FOR THE PURIFICATION OF WASTE WATER Abstract of the Disclosure: The waste water being formed upon the preparation of hydroxy aromatics, preferably of resorcinol and .beta.-naphthol, by caustic alkaline melt of the corresponding aryl-sulfonic acids or aryl sulfonates is purified by a wet oxidation with oxygen or oxygen-containing gases at temperatures of from about 100 to 370°C and under a pressure of from about 1 to 300 bar. The COD-decomposition rates amount to about 90% and more. This process provides a sulfate, especially sodium sulfate, which is sufficiently pure for further use without com-plementary purification stages, if the hydroxy aromatics are prepared by means of a caustic soda melt. The obtention of the pure salt is important for the economy of the process.

An Improved Procedure for Wet Oxidation of the 14C NBS Oxalic Acid Standard

Abstract: An improved procedure for wet combustion of 14C NBS oxalic acid standard has been devised which gives consistent high carbon yields and average S13C values of -19.1%. The principal cause of fractionation in earlier attempts to prepare CO2 by the wet oxidation method was the inexact nature of the end-point. The new procedure employs a chocolate-brown end-point by adding 5ml more of the sulfuric acid-potassium permanganate solution after the initial reddish brown end-point is reached. The sulfuric acid-potassium permanganate solution is added to the NBS oxalic acid in a steady drop-wise flow, heat is applied to the generating apparatus, and a cycling technique is utilized to collect the CO2. Fifteen samples of the NBS oxalic acid were processed. The per cent carbon yields range from 98.8 to 100.9% with an average of 99.7% and an average 3130 of -19.12%. The results obtained by this procedure are much more consistent than previous results obtained in several laboratories by direct combustion. WET OXIDATION OF OXALIC ACID Wet oxidation of the 14C NBS oxalic acid standard to carbon dioxide is an accepted technique used by most radiocarbon laboratories. The procedure is simple and straightforward. After some years of use, however, investigators have discovered that fractionation does occur during CO2 evolution because of difficulty in determining the proper end-point of the reaction. Fractionation during this chemical reaction has been documented by several investigators. Lindsay (1949) reported as much as 3.5% change in the 13C concentration in the CO2 during the decomposition of oxalic acid, and Bernestein (1957), working with formic acid decomposition by sulfuric acid, stated that as much as 53% variations occurred. Grey et al (1969), in preparing CO2 from the 14C oxalic acid standard, reported a 8130 value of -25.5% relative to PDB due to incomplete reaction. Fractionation during oxidation of the NBS oxalic acid standard is of concern because it may offset counting rates, resulting in systematic errors in age determinations. Craig (1961) determined the 13C/12C ratio of the standard gas samples from several laboratories, prepared by both wet oxidation and direct combustion in oxygen. 8130 values by direct combustion with oxygen ranged from -17.15 to -22.72% with an average of -19.3% (10 samples), while the wet oxidation values ranged from -18.37 to -31.37%0. Rejection of the four most depleted values gave an average of -19.6% (6 samples). According to Craig, depleted values are to be expected if the oxidation has not gone to completion. Since the primary 14C standard for the University of Texas Radiocarbon Laboratory is NBS oxalic acid (as it should be for all laboratories), the personnel of the laboratory were compelled to improve the wet oxidation procedure so that no significant fractionation would occur. * Radiocarbon Laboratory, University of Texas at Austin, Balcones Research Center, 10100 Burnett Rd, Austin, Texas 78758 ** University of Texas at Austin, Dept of Geological Sciences, Austin, Texas 78712

Waste water treatment method using activated carbon

Abstract: A method for effectively treating waste water discharged from the ammoxidation process for the production of acrylonitrile which comprises treating waste water or a preliminary oxidized liquid of said waste water with activated carbon in an adsorption and separation zone, subjecting the spent carbon slurry from said adsorption and separation zone to wet oxidation in the presence of copper values and ammonium ions at a pH of not higher than 5 in a regeneration zone to thereby regererate the spent carbon, and recycling the regenerated activated carbon to said adsorption and separation zone. The rate of regeneration of the spent carbon in the regeneration zone can be further increased by adjusting the amount of copper values to at least 1,000 ppm. Thus, the waste water containing extremely hardly decomposable substances can be effectively treated and, at the same time, the spent carbon can be regenerated with less degradation of adsorption capacity.

Removal of solids from a wet oxidation reactor

Abstract: A cleaning and washing system for a wet oxidation reactor with an associated heat exchanger. A by-pass (H), normally closed, communicating with the bottom of the reactor is opened while the normal flow of sludge is closed, for flushing out unwanted solid particles in the reactor after reducing the pressure setting of a pressure control valve (7) normally controlling flow from the outlet of the hot side of the heat exchanger. The by-pass also communicates with said pressure control valve.

Process for removal of hydrogen sulfide

Abstract: PURPOSE:In a wet oxidation process for converting hydrogen sulfide in the gas containing hydrogen sulfide to sulfur by contacting the gas with an absorbing solution containing redox catalysts thereby removing the hydrogen sulfide, arresting of fine sulfur particles is made easier by the use of surface active agents.

Wet oxidation of sulphur and the capture of generated heat

Abstract: A method for the manufacture of sulphuric acid wherein sulphur, in one case, and a source of sulphur in another case is reacted at superatmospheric temperatures and pressures with oxygen dissolved in an inert liquid in the presence of water, the inert liquid being selected from fluorocarbon compounds having eight or more carbon atoms. Heat is captured from the inert liquid.

Method of withdrawing liquid containing precipitationnconsolidating so lids from towers* tanks* etc*

Abstract: PURPOSE:For example, in such a wet oxidation desulfurization apparatus wherein the H2S contained in gas is absorbed into an absorbing solution to which air is blown to allow H2S to deposit as sulfur content which is recovered, the regenerated absorbing solution containing deposited solid sulfur is effectively taken out to the outside.