Boiler wet slag removal system

Abstract

The invention relates to a boiler wet slag removal system, which comprises a slag extractor and a heat exchanger. The slag extractor is located under the boiler and has a water tank for receiving boiler bottom slag. The heat exchanger includes a heat exchange surface, one side of the heat exchange surface introduces the water in the water tank as the first heat exchange medium, and the other side of the heat exchange surface is the flowing second heat exchange medium to absorb the water in the water tank energy. In one solution of the present invention, the second heat exchange medium can be air, which is provided by the blower or the primary blower of the boiler, and is sent to the air preheater for the boiler together with the cold air of the blower or the primary blower after being heated . In another solution of the present invention, the second heat exchange medium can be condensed water, which is provided by one or more low-pressure heaters of the steam turbine condensate system, and is heated and delivered to one or more low-pressure heaters . In this way, the waste heat of the slag can be recovered, which simplifies the structure of the wet slag removal system and reduces the water consumption.

Description

technical field [0001] The invention relates to slag removal for coal-fired boilers, in particular to a boiler wet slag removal system. Background technique [0002] For the boiler mechanical slag removal system in thermal power plants, the following two technologies are widely used at present, one is the wet slag removal system using the scraper slag remover, the other is the air-cooled dry slag removal system using the steel belt slag remover system. [0003] The equipment of the wet slag removal system of scraper slag machine mainly consists of water-immersed scraper slag machine, slag conveying equipment from slag machine to slag bin, slag bin, overflow pool, sedimentation tank, buffer pool and related cold slag Water pumps, flushing water pumps, sewage pumps, slag system make-up pumps, etc. Boiler bottom slag falls from boiler slag outlet and slag well into the upper water tank of the scraper slag extractor. After being cooled and cracked by the water in the water tan...

AI Technical Summary

Problems solved by technology

The main disadvantage of the dry slag removal system is that the important operating parameters of the system are not easy to control, and there are many deviations from the design values.

If the air volume for cooling the slag is too low and deviates from the design value, the temperature of the slag will be higher than 150°C to 200°C, and the insufficient cooling of the slag will endanger the safety of subsequent conveying equipment and operating personnel

If the air volume for cooling slag deviates too much from the design value, for example, it is higher than 1% to 1.5% of the total boiler air intake, the temperature of the air entering the boiler furnace will be lower than 250°C, resulting in unstable combustion of the boiler, and the proportion of cold air entering the furnace will be too high High, the efficiency of the boiler will decrease

In addition, the slag cooling of the dry slag removal system adopts natural air cooling, the cooling effect is poor, it is not easy to cool through the large slag, and the adaptability to the change of the amount of boiler slag is not strong

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