Method and device for oxidizing and treating sewage or sludge containing organic substances by supercritical water

Abstract

The invention relates to a method and a device for oxidizing and treating sewage or sludge containing organic substances by supercritical water. The method adopts a combustion reaction furnace, and is characterized in that substance flow of the sewage or the sludge containing the organic substances and oxidant (such as oxygen or hydrogen peroxide and the like) are preheated by a heat exchange device respectively and then enter the combustion reaction furnace, the sewage or the sludge containing the organic substances is oxidized and treated under a supercritical state, the treated substance flow is cooled by the heat exchange device again, then residual gas in the substance flow is separated by adopting a gas-liquid separator, and the lower part of the combustion reaction furnace discharges salt slag through a slag discharging hole and a valve. The method has the advantages of reasonable and practical process, energy conservation and low operation cost.

Description

technical field [0001] The invention relates to a method and a production device for treating sewage or sludge containing organic matter. Background technique [0002] Supercritical Water Oxidation (SCWO for short) technology uses water as the medium. In the supercritical state (temperature>374.3℃; pressure>22.1MPa), the interface between the liquid phase and the gas phase disappears, and oxygen can be dissolved in any proportion. , there is no problem such as the movement of substances between the gas-liquid phase interface and provides an ideal oxidation reaction environment, a method for oxidizing and removing organic substances suspended or dissolved in water. The SCWO method for sewage treatment has advantages unmatched by other existing sewage treatment technologies. The main manifestations are: the removal rate of harmful substances is almost 100%, and the degradation time is measured in seconds (depending on the type of organic matter, temperature and pressure)...

AI Technical Summary

Problems solved by technology

[0007] Incineration is the most thorough way to achieve sludge reduction. The advantage of dry incineration method is that there are few residues produced by incineration, and the ash after incineration has no peculiar smell; however, the investment in special treatment equipment for dry incineration is huge, and energy consumption Large amount (even if the sludge produced by the sewage treatment plant is mechanically dehydrated, the water content is between 75% and 85%. According to experiments and calculations, it is necessary to dry the sludge with a water content of 75% to 85%. The added energy is much greater than the energy produced by sludge combustion)

The operation cost is high, and the cost of sludge drying and incineration is more than 400 yuan / ton

Moreover, toxic and harmful gases such as dioxin will escape into the atmosphere during the incineration process.

[0008] To sum up, SCWO technology was first proposed by American scholar M. Modell in the mid-1980s and has not been able to enter the market for more than 20 years. The main reason is that it is limited to material preheating systems, supercritical water medium heating systems, oxidants ( Oxygen) The connection between the heating system and the reactor is too complicated, and the material requirements of the equipment are very high. Not only the equipment construction and production operation costs are high, but also the operation of the entire system is very unreliable.

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