【Q&A Question 005】2018.01.05
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This post was last edited by liuquan1100 on 2018-1-5 08:35. [Q&A Question No. 005] January 5, 2018: How does the boiler water in the steam generation system of a hydrogen production waste heat boiler circulate? The waste heat boiler operates in natural circulation; it uses the converted gas as a heat source, and is connected to the steam drum to form this natural circulation. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) For management purposes, if you need to view content from a few days ago, please go through the summary post below. Summary post of daily questions on hydrogen production and hydrogenation technologies in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888971Summary post of daily images on hydrogen production and hydrogenation technologies in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970
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The waste heat boiler operates in natural circulation; it uses the converted gas as a heat source, and is connected to the steam drum to form this natural circulation.
Water enters the evaporator from the atmosphere, and thanks to the principle of thermal siphonage, steam enters the atmosphere!
The boiler water enters the boiler through the downcomer from the drum to exchange heat with the flue gases; the resulting vapor-water mixture returns to the drum via the upcomer.
The cyclic flow of a mixture of water and soda in the boiler’s evaporation and heating surface circuits is called the boiler’s water circulation. Since the density of water is greater than that of the soda mixture, the circulation of water and the soda mixture resulting from this density difference is called natural convection. In a steam boiler, once the feed water enters the boiler, it flows continuously along a specific circulation path. During this continuous flow process, water is heated and vaporized by the evaporation surfaces, producing steam. The steam mixture generated by these surfaces gathers in the drum; there, it is separated from the water due to gravity or mechanical means, after which the steam is extracted ； The heating surface, namely the metal wall, relies on the water circulation to remove the heat transferred from the hot flue gases, thereby keeping the wall temperature within the allowable operating range for metals and ensuring the long-term reliable operation of the evaporation heating surface. Water enters the unheated downcomers from the boiler drum, and then flows through the lower header into the upcomers located inside the furnace ； In the rising pipe, part of the water vaporizes upon heating; the mixture of steam and water then rises due to its low density and returns to the boiler drum, thus creating a natural circulation of water ； Any boiler is composed of such several cycles.
The water drawn from the lower part of the drum is pressurized by a circulation pump and then divided into two streams to enter Evaporator I and Evaporator II. Inside the evaporators, the water absorbs heat from the flue gas; part of the water turns into steam. The vapor-water mixture resulting from this process then flows back to the drum through pipes. Rely on the power generated by the circulation water pump to circulate the water
The waste heat boiler operates in natural circulation; it uses the converted gas as a heat source, and is connected to the steam drum to form this natural circulation.
The last edit to this post was made by Chizi Xincheng on 2018-1-5 at 13:16. The demineralized water from outside the device enters the deaerator where thermal deoxidation takes place; the resulting deoxygenated water then enters the steam drum. It is necessary to maintain a zero hardness level in the water inside the steam drum, which is why regular drainage is required to remove this water from the system. The drain tank is connected to one side for supplying circulating water, and to another side for returning water to the deaerator； The drum emits saturated steam, which exchanges heat with the feed gas to produce condensed water that is sent back to the deaerator. Superheated steam is then generated and mixed with the feed gas, before entering the conversion reactor; there, heat exchange leads to the formation of acidic water, which is purified through steam stripping to yield clean water, which is subsequently pumped into the deaerator.
The waste heat boiler operates in natural circulation; it uses the converted gas as a heat source, and is connected to the steam drum to form this natural circulation.