Coal-fired power plant online sludge drying and mixing combustion system and application method thereof

Abstract

The invention relates to a coal-fired power plant online sludge drying and mixing combustion system and an application method thereof. The coal-fired power plant online sludge drying and mixing combustion system comprises a boiler hearth, a dust collector, a desulfurizing tower, a chimney, a stacking tank, a drying tank, a to-be-mixed tank and a mixing combustion conveyer. The boiler hearth is connected with a flue. An outlet of the stacking tank is connected with a sludge feed port of the drying tank. A sludge discharge port of the drying tank is connected with an inlet of the to-be-mixed tank. An outlet of the to-be-mixed tank is connected with the mixing combustion conveyer. The mixing combustion conveyer conveys a mixture of dry sludge and coal to the boiler hearth to be combusted. A flue gas inlet of the drying tank is connected with an outlet flue of the boiler hearth through an air pumping pipeline. A flue gas outlet of the drying tank is connected with the outlet flue of the boiler hearth through an air return pipeline. The coal-fired power plant online sludge drying and mixing combustion system guides flue gas to get into the sludge drying tank to dry sludge to achieve secondary utilization of the flue gas and online drying of the sludge. Under the condition of not affecting the boiler efficiency, real-time drying and real-time mixing combustion of the sludge are realized. The cost of drying and mixing combustion at different time and different places and the sludge transportation cost in the drying and mixing combustion process are reduced.

Description

technical field [0001] The invention relates to the technical field of environmental protection treatment, in particular to an online sludge drying and blending combustion system in a coal-fired power plant and its application. Background technique [0002] Sewage sludge contains a large amount of organic pollutants, germs, heavy metals, and carcinogenic chemicals. With the acceleration of urbanization in my country, the amount of urban sewage treatment has increased year by year, and the sludge output of sewage treatment plants has also increased sharply. After the treated sludge enters the environment, it will pose a serious threat to humans and the environment. At present, harmless incineration treatment is an effective method for sludge treatment, which can effectively reduce and make it harmless. [0003] Sludge blending is one of the main methods of sludge incineration treatment. Existing pollutant control devices in coal-fired power plants can be used to deal with har...

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Problems solved by technology

[0005] However, this patent has the following deficiencies in online sludge drying and co-combustion: (1) The patent directly extracts the high-temperature flue gas in the furnace before the economizer, which affects the heating of the superheater reheater by the flue gas, and The high-temperature flue gas in the furnace will cause the wet sludge to produce highly toxic and harmful substances such as dioxin during the drying process, and at the same time reduce the flue gas volume of the economizer and air preheater, so that the waste heat of the flue gas cannot be effectively used , which reduces the thermal efficiency of the boiler; (2) The sludge dryer described in this patent does not explain the problems of uneven heating of wet sludge and flue gas bypass in the introduced flue gas, which will further affect the wet sludge. The degree of dryness affects the overall efficiency of the boiler; (3) The sludge dryer described in this patent dries the wet sludge and directly transports it to the coal conveyor belt, which cannot solve the problem of sludge storage and limits the boiler’s blending ratio. (4) There is no safe disconnection measure between the wet sludge bin and the sludge dryer described in the patent, which will cause the phenomenon of idling of the dryer; (5) The drying described in the patent The induced draft fan is connected to the economizer and the dust collector respectively, and the dry flue gas directly entering the dust collector will affect the performance of the dust collector and interfere with the mainstream flue gas; (6) The dry induced draft fan connected to the dust collector pipe and the dust collector There is a large wear and disturbance at the joint of the device, which increases the power consumption of the induced draft fan and reduces the overall efficiency of the unit; (7) the coal conveyor belt described in this patent sends the coal and sludge mixture to the furnace, and there is a problem of inappropriate mixing. Uniformity will affect the combustion conditions in the furnace, and there will also be situations such as sludge throwing and falling

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