Carbon dioxide heat pump sludge drying system

Abstract

The invention discloses a carbon dioxide heat pump sludge drying system, which comprises: a sludge drying unit, which is used for drying sludge to obtain dried sludge and wet and hot air; a carbon dioxide heat pump unit, which is used for enabling the damp and hot air flowing into the carbon dioxide heat pump unit from the sludge drying unit to form dry high-temperature air and then returning the dry high-temperature air to the sludge drying unit, wherein the dried high-temperature air is used as a heat source for drying the sludge. By using the supercritical CO2 heat pump unit, the exhaust temperature of a compressor is high, CO2 latent heat is high, and condensation is avoided, so that the temperature of a hot air outlet can reach 100 DEG C or above, and the drying efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of sludge treatment, in particular to a carbon dioxide heat pump sludge drying system. Background technique [0002] Sewage treatment will produce a large amount of sludge, which is toxic and contains a large amount of organic matter. How to treat this sludge in a harmless manner has become an important issue in our country today. The existing sludge treatment methods are mainly landfill and pollution-free incineration after drying. Disposing of sludge by landfill not only wastes land resources but also causes secondary pollution to the environment. Therefore, harmless incineration of sludge is currently the most effective way of sludge treatment. Before incineration, the sludge is generally pre-dried to reduce the water content to a certain range, so as to improve the combustion conditions and achieve the purpose of harmless incineration. On the other hand, for enterprises, sludge is a hazardous waste, c...

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Problems solved by technology

[0003] There are many kinds of sludge drying equipment, such as rotary disc, flash evaporation, paddle type and heat pump drying equipment, among which rotary disc, flash evaporation, paddle type, etc. have high energy consumption and large heat loss However, although the existing sludge heat pump drying equipment is a new type of energy-saving sludge drying equipment, the current problem is that the heating temperature of ordinary heat pumps is relatively low, usually only up to about 70°C, and it is used for sewage. When the sludge is dried, due to the low temperature, the drying is not thorough, the moisture content of the sludge is still high after drying, and the sludge drying efficiency is low;

[0004] Traditional sludge drying equipment uses mud rollers to flatten the mud cake and spread the mud cake. However, during the drying process of this method, the sludge cannot be fully spread and thinned, and it is easy to form large clumps. The sludge and hot air The small contact area leads to slow drying rate, the foul smell and harmful gas generated during the drying process are easy to overflow, and the operating conditions are poor, especially when the surface of the spread sludge dries quickly, it is easy to form a hard skin, which hinders the moisture inside the sludge If the sludge is further volatilized, if the sludge is not further pulverized, the drying rate will be reduced and the heat utilization rate will be reduced; the traditional sludge drying equipment uses a conveyor belt to transport the sludge, which not only occupies a large area, but also because the sludge generally has a certain Viscous, easy to adhere to the conveyor belt, or even block the transmission channel; the transmission of the conveyor belt will not only restrict the flow of hot air, prevent the formation of strong convection between the sludge and the hot air, but also make the contact between the sludge and the conveyor belt The moisture volatilization is hindered, the drying rate is reduced, and the heat utilization rate is reduced

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