Angular pipe water circulating structure with complete forced upward flowing on heating surface

Abstract

The invention discloses an angular pipe water circulating structure with complete forced upward flowing on a heating surface. The angular pipe water circulating structure is composed of a hearth arranged on a fire grate, a membrane-type water cooling wall heating surface and a membrane-type wall heating surface of a convection vertical shaft, wherein the membrane-type water cooling wall heating surface is adjacent to the membrane-type wall heating surface of the convection vertical shaft; and a boiler main body is of a self-supported framework type structure composed of large-diameter steel pipes arranged at four corners of the structure, a boiler and a header. Accordingly, the defects of pipe explosion, low-load operation incapability and power-failure protection deficiency are avoided, the advantages of steel frame saving, good airtightness, less leaked air, no pipe explosion and high combustion efficiency are achieved, and the angular pipe water circulating structure can be ensuredto operate safely and reliably at any loads, has a superstrong power-failure protection function, and is beneficial to effective reduction of dangerous working conditions of low-temperature corrosionand dust clogging caused by moisture condensation of sulfuric acid in the smoke.

Description

technical field [0001] The invention relates to the technical field of thermal energy engineering, in particular to a corner tube water circulation structure in which all heating surfaces are forced to rise and flow. Background technique [0002] Since 2000, with the development of my country's industrialization and urbanization, the improvement of energy conservation and environmental protection requirements, and the huge increase in urban heating demand, large-capacity layer-fired coal-fired central heating boilers have entered a period of rapid development. Large-scale floor-fired boilers are the main successful experience in the popularization and application of energy saving and emission reduction under the new situation in my country. According to the research on the operation status of large-capacity layer-fired coal-fired central heating boilers in the market, water-fire tube boilers are transitional products from internal combustion to external combustion during the...

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Problems solved by technology

[0003] At present, the corner tube boilers that have been produced are technical products introduced by my country through the GEF project in 1992 after being selected by experts from many foreign industrial boiler products. They mainly have two structures: natural circulation and forced circulation. They have been in operation for many years. There have been some problems, but it has not been recognized by the market. After market research, it has been found that the imported technology is not suitable for my country's coal types except for the open furnace and furnace arch technology in the combustion system. The existing angle tube technology has the following hidden dangers in terms of long-term operation safety :

[0004] (1) The existing natural circulation angle-tube hot water boilers are all made of membrane water-cooled walls. Since the membrane-type water-cooled walls are welded by smooth tubes and flat steel, once a membrane-type water-cooled wall bursts, it will be difficult to maintain It is very large, and the maintenance period is long. It is difficult to guarantee the quality of butt welding during on-site maintenance, and it is easy to leave welding hidden dangers and become a new cause of pipe explosion.

Due to the extremely unstable heating load of the hot water boiler, the flow rate of hot water varies greatly with time. During natural circulation, abnormal hydrodynamic conditions such as stagnation or reverse flow often occur, which deteriorates the heat transfer capacity and causes the wall temperature to soar, resulting in The tragedy of the squib

[0005] (2) In addition, hot water boilers have great load variability during the heating process, and the circulating water volume varies between 50% and 100%. When the load changes, the minimum safe water for natural circulation and forced circulation hot water boilers The speed is difficult to maintain, and the water flow rate in the tube bundle flowing down the furnace water wall may cause stagnation and reverse flow of the water cycle due to the low water flow rate. question

For forced circulation hot water boilers operating on the market, in most cases, partitions are arranged inside the upper and lower headers of the membrane water-cooled wall to divide the entire heating surface of the water-cooled wall into upward and downward circulation loops. When the downflow circulation loop operates at low load and suddenly loses power, there will inevitably be hydrodynamic conditions such as stagnation of water circulation and reverse flow. The existence of such conditions seriously threatens the safety of the operation and management of hot water boilers. Therefore, the existing forced circulation The low load and power failure protection problems that may occur in the way affect the popularization and application of advanced technology products

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