Low-temperature sludge drying technology

Abstract

The invention discloses a low-temperature sludge drying technology and relates to the field of a sludge drying technology. The technology comprises the following steps: crushing wet sludge and carrying out extrusion moulding, entering a belt-type sludge drying box, carrying out heat transfer and mass transfer with hot dry circulating air to obtain dry sludge and wet low-temperature circulating air, inhaling the wet low-temperature circulating air into a heat pump through a circulating fan, further lowering temperature by heat exchange between the air blown from a circulating fan into an intermediate heat exchanger and evaporated outlet air, discharging air out of the intermediate heat exchanger, lowering temperature by a water-cooling pre-cooling coil pipe, evaporating by an evaporator after air-out, separating out condensed water, carrying out heat exchange between evaporated outlet air and heat-pump return air through an intercooler, raising air-outlet temperature and then entering a condenser, and letting hot dry air obtained after temperature rise enter a band-type sludge drying oven for cycling treatment. The invention has the following advantages: energy consumption is low; there is no secondary pollution; drying temperature is low; safety is high; degree of automation is high; and sludge drying cost is reduced.

Description

technical field [0001] The invention relates to the technical field of sludge drying, in particular to a low-temperature sludge drying process. Background technique [0002] Sludge drying is a necessary intermediate process of sludge treatment. From direct application to direct incineration, from application after drying, to incineration after drying, until the latest gasification after drying, drying is basically affirmed as a The importance of necessary intermediate processes. There are two main reasons: economy, whether it is the reduction of transportation and disposal, or the reduction of energy consumption; sanitation, the necessary condition for agricultural use. The final disposal method of sludge drying is the choice of national conditions, and landfilling is undoubtedly not advisable. This is not only because of the expensive land value, but mainly from the perspective of energy and bioenergy resources. The country requires reducing and restricting sludge landfill...

AI Technical Summary

Problems solved by technology

[0005] (1) High energy consumption: the energy demand is a minimum of 620 kcal per liter of evaporation, and the direct heating drying equipment processor claims that the thermal energy demand of its system is 800-850 kcal

[0006] (2) Bringing secondary pollution: drying sludge and polluting tail gas need to be treated again to meet the emission standards

[0007] (3) High drying temperature brings drying safety problems: the explosion and toxicity of substances that may volatilize from the sludge in the high-temperature drying sludge airflow are unavoidable

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