Showing papers on "Wet oxidation published in 1984"

A rapid accurate wet oxidation diffusion procedure for determining organic and inorganic carbon in plant and soil samples

Abstract: A method is presented for determining organic carbon content of soils, extracts and plant tissue utilizing an acidic wet oxidation in modified culture tubes; samples containing carbonates are pretreated with dilute acid. Evolved CO2 is trapped in a NaOH solution and quantified titrimetrically. The method described has a range of 0.4–11 mg. carbon and the range can be extended in either direction by modifying the CO2 trapping/titration procedure. This method is as accurate and precise as more time consuming dry oxidation procedures.

Supercritical Water Destruction of Aqueous Wastes

Abstract: For aqueous wastes containing 1 to 20 wt% organics, supercritical water oxidation is less costly than controlled incineration or activated carbon treatment and far more efficient than wet oxidation. Above the critical temperature (374°C) and pressure (218 atm) of water, organic materials and gases are completely miscible with water. In supercritical water oxidation, organics, air and water are brought together in a mixture at 250 atm and temperatures above 400°C. Organic oxidation is initiated spontaneously at these conditions. The heat of combustion is released within the fluid and results in a rise in temperature to 600-650°C. Under these conditions, organics are destroyed rapidly with efficiencies in excess of 99.999%. Heteroatoms are oxidized to acids, which can be precipitated out as salts by adding a base to the feed. Examples are given for process configurations to destroy aqueous wastes with 10 and 2 wt% organics. Disposal costs are given as functions of waste throughput.

Microanalysis of reaction products in sealed tube wet air oxidations by capillary gas chromatography

Abstract: Capillary gas chromatography can be used to analyze the reaction products of the oxidation of a compound in aqueous solution. A sealed glass capillary tube is used as the reaction vessel in which the compound and its products of oxidation are confined. The contents of the sealed tube are released upon crushing and are swept directly into the carrier gas stream of the gas chromatograph using a novel technique. As an example, the technique outlined in this paper is used to determine the combustion products of the wet air oxidation treatment of phenol; however, it may be used for any reaction in which volatile products are formed. A microanalysis technique is described which offers advantages over previously reported methods. The oxidation reaction at elevated pressure and temperature occurs in a sealed glass capillary tube and the reaction products are subsequently quantitatively introduced directly into a fused silica capillary column coated with a cross-linked polymer for gas chromatographic separation and analysis.

Similarities and Differences in Pretreating Woody Biomass by Steam Explosion, Wet Oxidation, Autohydrolysis, and Rapid Steam Hydrolysis/Continuous Extraction

Abstract: Steam hydrolysis processes are excellent methods for pretreating and fractionating cellulose from the other major wood components. In this study a comparison was made between four pretreatment processes: steam explosion; wet oxidation; autohydrolysis; and a new process based on rapid steam hydrolysis/continuous extraction. The biomass feedstock used was a low-cost woody substrate consisting of mixed southern hardwoods obtained by total tree chipping. The four pretreatments all employ steam or water and heat; however, there are fundamental differences between each process. The initial reaction involves a mild acid-catalyzed hydrolysis reaction of both the glycosidic bonds of the hemicelluloses and the ..cap alpha..-ether linkage in lignin. Even though the initial reactions for the four processes are similar, the final products are quite different due to the variety of secondary reactions which occur. All four pretreatments dramatically increased the enzymatic hydrolysis rates. However, only the wet oxidation pretreatment increased the acid hydrolysis rate. The hemicelluloses were depolymerized by autohydrolysis, wet oxidation, and steam explosion. The Rapid Steam Hydrolysis/Continuous Extraction process also depolymerized the hemicelluloses but minimized further degradation of the polysaccharides. The lignin was depolymerized by all pretreatments but apparently recondensed at the higher autohydrolysis temperatures. The solid residue remaining after a 260/supmore » 0/C Rapid Steam Hydrolysis pretreatment had an enriched cellulose content of about 70%.« less

Liquid gas injection system for wet oxidation vessel

Abstract: Means for injecting mixtures of pure oxygen or oxygen-enriched gas and inert purge liquid into wet oxidation reactors intemally clad or lined with titanium comprises an outer titanium pipe and an inner concentric pipe or material less reactive than titanium in an oxygen-rich atmosphere. Oxygen-rich gas and purge liquid are passed through the inner pipe into the reactor and a liquid low in molecular oxygen and corrosiveness is passed through the outer pipe annulus into the reactor.

Use of copper (II) oxide as source of oxygen for oxidation reactions

Abstract: This invention comprises a wet oxidation process utilizing copper (II) oxide as the sole oxygen source. In particular the destruction and detoxification by oxidation of toxic materials such as cyanide, hydrocarbons, halogenated hydrocarbons, and dioxins contained in typically aqueous streams by using copper (II) oxide is contemplated. The preferred embodiment involves adding the copper (II) oxide to the feed stream containing the toxic materials and reacting the stream under elevated pressure and elevated temperature conditions to substantially oxidize the toxic materials to less toxic or innocuous compounds. The oxidation process can be accomplished in a vertical tube reactor system, wherein the necessary pressure for the wet oxidation is achieved by hydrostatic head pressure inherent in the system.

Conversion of biomass into chemicals with high-temperature wet oxidation

Abstract: Etude experimentale de l'influence de la pression d'oxygene, de la temperature, du type de bois et de l'addition de sulfate ferrique sur le rendement en acides organiques lors de l'oxydation de bois humide a haute temperature (127-277°C)

Process for reducing the bound water content of coal

Abstract: A process for reducing the water content of coal containing bound water by treating the coal at an elevated temperature and pressure in a de-watering zone in the presence of liquid water to remove liquid water from the coal and treating liquid water in the de-watering zone or liquid water removed from the coal or both by a wet air oxidation process.

Wet type oxidation device

Abstract: PURPOSE:To obtain a wet type oxidization device of a small size having good efficiency, by constituting the same of a production device for gaseous O2 of >=21vol% concn. of O2 and a wet type oxidation device body which uses the gaseous O2 obtd. by said device as an O2 source by utilizing the back pressure thereof. CONSTITUTION:A production device 8 for gaseous oxygen 8 pressurizes raw material air to about 3-5kg/cm G with an air compressor 9, feeds the same into an adsorption cylinder packed therein with a nitrogen adsorbent such as molecular sieves or the like, and produces gaseous oxygen of a high oxygen concn. by adsorbing and removing the nitrogen in the air on and by the nitrogen adsorbent. The satd. nitrogen adsorbent on which nitrogen is adsorbed is decreased in pressure down to the atm. pressure by which the adsorbent is regenerated. The regenerated adsorbent is reused. Gaseous oxygen having about 1kg/cm G back pressure is obtd. from the device 8 when the pressure of the raw material air is 3kg/cm G. Such back pressure is used as it is and the gaseous oxygen is fed as an oxygen source into a wet oxidation device body 7.

Catalyst for wet oxydation treatment

Abstract: PURPOSE:To give an excellent catalytic activity to a catalyst by using Ru, Rh, Pd, Ir, Pt, Au and the water-soluble or hardly soluble compds of the above- mentioned metals as effective components, and using TiO2 having anatase type crystal and rutile type crystal as carrying catalyst in a specified composition ratio as a carrier CONSTITUTION:A catalyst for wet oxidation treatment to be used for decomposing COD components, ammonia etc in waste water is composed of one or >=2 kinds among Ru, Rh, Pd, Ir, Pt, Au and the water-soluble or hardly soluble compds of the above-mentioned metals as effective components TiO2 composed of 1ptwt anatase type crystals and 01-6ptswt rutile type crystals as the carrying catalyst is used as a carrier The amt of effective components of the catalyst is regulated to 005-25wt% (especially 05-3wt%) of the carrier

Treatment of organic treating material subjected to wet oxidation or heat treatment

Abstract: PURPOSE:To increase the amt. of the digester gas to be produced without generating malodor with an anaerobic digester treatment of separated liquid by subjecting the org. treating material subjected to a wet oxidation treatment to a flocculation treatment at pH on an adequate acidic side in the presence of ferric salt thereby forming the separated liquid. CONSTITUTION:Org. treating material, such as sewer sludge, is passed through a concentration stage 10 for sewer sludge and is oxidized in a wet oxidization treatment stage 11 consisting of a high pressure pump 101, a compressor 104 for supplying air, a heat exchanger 102, a reactor 103, a gas-liquid separator 105, etc. in a wet oxidation treatment system A and is introduced into a flocculating stage 12. Ferric salt, such as ferric chloride, is added at >=100mg/l, more preferably 500-2,000mg/l in terms of iron by a means 107 for adding and mixing a flocculating agent to the org. treat material L1 accepted in a flocculating and settling tank 106 where the material is flocculated at 2.5-7.0, more preferably 3-5pH. At least a part of the separated liquid L2 thereof is introduced into an anaerobic treatment system B, and is subjected together with the treated material from the other system introduced from a pretreatment stage 13 to an anaerobic digestion treatment 14, dehydration treatment 16 and activated sludge treatment 18.

Chemische Methoden der Abwasser‐Aufbereitung

Abstract: Chemical methods of waste-water treatment. Chemical methods of waste management by oxidation can be considered for particular effluents whose constituents are degraded too slowly in conventional sewage treatment plants or which interfere with the biodegradation of other substances. Of these methods, those we have to choose from today are, in order of increasing operating temperature: oxidation with hydrogen peroxide – wet oxidation at high pressure – evaporation and combustion. None of these methods is fundamentally better than the others, i.e. none has a maximum ecological benefit coinciding with a minimum economic impact. Detailed experimental work is required to establish the limits and possibilities in each case and thus to form a basis for useful comparisons. Thermal processes are normally ruled out for low concentrations of degradable constituents in waste water because the specific energy costs per unit volume are too high; this is where hydrogen peroxide may offer advantages, especially when the proportion of these constituents fluctuates. With higher concentrations, wet oxidation can be employed; evaporation and combustion are suitable if there is also a high concentration of inorganic salts.