System and method for drying municipal sludge by utilizing slag dryer of coal-fired boiler of power station

Abstract

The invention discloses a system for drying municipal sludge by using a slag drying machine of a coal-fired boiler of a power station. A sludge conveying assembly located above a slag conveying assembly is arranged on an inclined section in the slag drying machine; the system further comprises a wet sludge bin, a wet sludge pipe communicated with an inner cavity of the wet sludge bin is arranged at the bottom of the wet sludge bin, and a wet sludge input assembly extending to the surface of the lower end of the sludge conveying assembly is arranged at the discharging end of the wet sludge pipe. A spiral feeder extending outwards is arranged in the slag drying machine and located below a discharging opening of the sludge conveying assembly, and the air inlet air door is arranged on the side wall of the slag drying machine and the top where the inclined section of the slag drying machine is located. According to the sludge drying system, physical sensible heat of the slag is fully utilized, the energy-saving effect is remarkable, a fan does not need to be additionally arranged, the system is simple and free of environmental pollution, indirect heat exchange between the slag and the sludge is achieved through cooling air, the sludge and the slag are not mixed, and follow-up resource utilization of the dry sludge is facilitated.

Description

technical field [0001] The invention relates to the technical field of sludge recovery and treatment, in particular to a system and method for drying urban sludge by utilizing a coal-fired boiler slag dryer in a power station. Background technique [0002] The sewage in the urban municipal sewage pipe network will produce a large amount of sludge after being treated by the sewage treatment plant. The urban sludge generally has a moisture content of about 80%, contains harmful substances such as bacteria, parasites, and heavy metals, and will produce unpleasant temperatures. At present, my country's The sludge treatment methods mainly include landfill, composting, natural drying, incineration, etc. The proportion of these four treatment methods is 65%, 15%, 6%, and 3% respectively. Landfill is the main treatment method of sludge in my country, but the output of urban sludge in my country continues to rise. At present, the annual output of urban sludge is more than 40 million t...

AI Technical Summary

Problems solved by technology

[0005] Disadvantages: 1) Wet sludge has high moisture content and high viscosity, which can easily cause blockage of raw coal bunkers, so it can only be blended in a very small proportion, and the safety risk is large, and the practicability is not high; 2) Considering that the boiler exhaust gas temperature is generally higher than 100°C, so the latent heat of vaporization cannot be used after the water in the wet sludge is heated, and the low-level calorific value of the wet sludge with a moisture content of 80% is mostly about 0, so direct blending and combustion cannot reduce the use of fuel and cannot be realized. "Resource"

[0009] The above-mentioned sludge drying method is to mix wet sludge with slag, and use the heat of slag to dry the sludge. The dried sludge and slag are transported to the raw coal bunker together, mixed with coal and burned. The main disadvantage of this method is: boiler slag The amount is relatively large and almost all ash content. After blending with coal, the average calorific value of coal will drop more, and the ash content will increase, which will easily cause problems such as boiler fire extinguishing, equipment wear, and efficiency decline. The practicability is poor.

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