Double wet back cooling device for horizontal internal combustion multi-pass boiler

Abstract

A horizontal double-wet-back cooling device for an internal combustion multi-return-stroke boiler comprises a tempering reversing chamber arranged in a boiler barrel. The two ends of the tempering reversing chamber are respectively provided with a tube board. Smoke tubes in the boiler barrel are respectively arranged on the tube boards in a penetrating mode and communicated with the inner portion of the tempering reversing chamber. Conversion heat-exchanging tubes are vertically arranged in the tempering reversing chamber from top to bottom. The two ends of each conversion heat-exchanging tube respectively stretch out of the tempering reversing chamber. The middles, in the center of the tempering reversing chamber, of the conversion heat-exchanging tubes are respectively bent outwards so that a repairing channel can be formed. The lower surface inside the boiler barrel is provided with water supplying injection tubes of an arc structure and each water supplying injection tube is provided with an injection opening vertically corresponding to a lower port of the corresponding conversion heat-exchanging tube. The horizontal double-wet-back cooling device is reasonable in design and simple in structure; temperature of smoke in the tempering reversing chamber is reduced; the operation environment of the tube boards is improved; the water supplying injection tubes are arranged, so that water circulation of the conversion heat-exchanging tubes is prevented from being deteriorated.

Description

technical field [0001] The invention relates to a boiler, in particular to a double wet back cooling device for a horizontal internal combustion multi-pass boiler. Background technique [0002] For a long time, my country has been using coal as the main energy source, and coal-fired boilers have been used extensively, resulting in soot-type air pollution, especially the smog that has occurred in many places in recent years, which has further promoted the transformation of my country's energy policy and energy structure as soon as possible. At present, the use of coal-fired industrial and domestic boilers in our country is huge, which is an important source of pollution that causes smog in our country. Therefore, some large and medium-sized cities in my country have recently formulated regulations for changing industrial or domestic coal-fired boilers to fuel oil or gas. Boiler policy, which can not only solve the outstanding contradiction between boiler coal burning and the e...

AI Technical Summary

Problems solved by technology

However, during the use of this kind of boiler, due to structural limitations, some accidents often occur. One of the main common accidents is that the rear tube plate of the boiler smoke pipe is prone to cracks. Over the years, manufacturers and users have adopted There are many methods, but the effect is not very satisfactory. At present, most boilers use multi-return wet-back shell boilers with back-fired steering chambers in the middle. The cracks mainly appear in the welds of the tube sheets and smoke tubes. It is mainly due to the stress cracks caused by the large temperature difference between the inside and outside of the tube sheet. The temperature difference of the medium is too high. Although the wet-back flashback steering chamber is generally used after technological progress, the temperature drop of the high-temperature flue gas entering the flashback steering chamber is limited, and the water temperature in the drum is very low, resulting in a temperature difference between the inside and outside of the tube sheet. It is very large, especially the smoke tube passing through the tube plate and the tube plate are welded, and the cooling at the weld is poor. Under the heating of high-temperature flue gas, due to the repeated stress, the connection between the tube plate and the smoke tube The welds are prone to stress fatigue cracks. As time goes by, under the water pressure in the pot shell, the cracks will soon leak. At this time, an emergency shutdown of the furnace is required for maintenance. , in this kind of WNS horizontal internal combustion multi-pass shell boiler, it is a frequent accident. After years of research into the cause, it was found that the room temperature of the return combustion was too high, which made the temperature difference between the inside and outside of the weld of the tube sheet and the smoke tube Under the repeated action of stress, fatigue cracks appear as the main reason

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