Industrial riser device technology for recovering waste heat from coke oven waste gas
Firstly, use several key words: riser heat exchanger, nanotechnology, waste heat recovery of raw gas, energy conservation and emission reduction.
preface:
The coking industry must adhere to green development, effectively reduce energy consumption, material consumption, and pollutant emissions, further develop circular economy, and focus on strengthening the research and promotion of key energy-saving and environmental protection technologies, processes, and equipment. The successful research and development of coke oven waste gas waste heat recovery and utilization devices is a major breakthrough and also one of the energy-saving and emission reduction measures in the coking industry.
What is a tamping coke oven:
Stamping coke oven refers to the coke produced using tamping coking technology in a special type of tamping coke oven, which is called a tamping coke oven. (Advantages: saving resources, environmental protection, improving coke quality, economic benefits),
Research and Development Background:
Since the late 1970s, multiple coking enterprises at home and abroad have adopted various process schemes for trial and practice, but eventually stopped due to factors such as high investment and low efficiency. In the past 30 years, the research and development of waste heat recovery technology for coke oven raw gas has been the main focus of energy conservation for coking workers in China, especially in recent years, the technical achievements of several leading teams in China have their own strengths.
Structural diagram of special structure water jacket waste heat recovery technology for riser heat exchanger
Sectional diagram of riser structure
Do not change the original size of the inner cylinder of the riser
Internal structure diagram of riser
Comparison of traditional riser and newly developed riser samples
Technical Description:
1. Technical principles and key technologies: This device is an efficient, reliable, and stable core device for recovering and utilizing sensible heat from coking waste gas. It recovers and utilizes the sensible heat from waste gas to produce steam for subsequent use, realizing its industrial application in the coking industry and promoting energy conservation and emission reduction in the entire coking industry.
As the raw gas contains tar steam, water steam, benzene steam, etc., and the temperature is lower than 450 ℃, the middling coal tar of the raw gas will condense. When the temperature is higher than 800 ℃, the carbon in the raw gas will gather to form graphite. In addition, only in the circular cavity of the riser with a diameter of 400~500mm can we think of ways to do this. The heat exchanger cannot leak water into the carbonization chamber, which is what coking practitioners often call "three fears": fear of water leakage, fear of graphite growth, and fear of tar hanging.
The key technology for recovering raw gas is the heat exchanger installed inside the riser. This new type of riser heat exchanger technology has three functions: water leakage prevention, stone ink prevention, and tar hanging prevention.
One: The selection of material for the riser heat exchanger
New high-temperature, corrosion-resistant, and wear-resistant alloy materials; By fully utilizing the high temperature resistance, wear resistance, and corrosion resistance characteristics of special materials, the strength of the shell is enhanced. The organic combination of the material and the lining layer meets the needs of the medium under special working conditions such as high temperature, large temperature differences, and corrosion (oxidation, reduction, H2S, etc.).
Secondly, it is a solution to prevent water leakage in the riser. The inner wall of the inner cylinder is an integral structure made of wear-resistant, corrosion-resistant, and high-temperature resistant alloy materials, which melt and form in a high-temperature environment, equivalent to a seamless alloy body as a whole. Water vapor heat transfer occurs in a closed space, where the inner wall of the heat exchanger is made of an alloy integral structure with a lining layer. A new type of high-temperature resistant, corrosion-resistant, and wear-resistant alloy material is used, which melts and forms in a high-temperature environment, equivalent to a seamless alloy body. Water will not leak into the carbonization chamber.
Thirdly, the solution to the problem of tar and graphite accumulation in the inner cylinder of the riser
(1) The inner wall of the riser heat exchanger is made of high temperature resistant and corrosion-resistant materials, with a lining layer and self-cleaning material coating. The inner surface is uniform and smooth, without dead corners, and will not accumulate graphite or coal tar.
(2) By controlling the inflow flow rate of the steam drum, the temperature difference between the inlet and outlet of the riser is to some extent controlled, which reduces the condensation of tar and graphite on the inner wall through another means. The inner surface of the rising tube heat exchanger is uniform and smooth, which is not easy to hang stone ink and condense coal tar, and even trace adhesion is easy to remove; By controlling the inflow rate of the steam drum, the temperature difference between the inlet and outlet of the rising pipe for hot water exchange is controlled, eliminating the possibility of tar and graphite condensation on the inner wall.
(3) The inner wall of the heat exchanger is smooth as a whole, and even if tar and graphite accumulate, they are not easy to adhere. Even if they adhere, they are also easy to remove.
Fourthly, the enhancement of heat exchanger efficiency
(1) The internal structure of the heat exchanger is arranged scientifically and efficient heat transfer materials are selected to greatly improve the heat transfer effect.
(2) By using a forced circulation pump, high flow and head, and segmented pipeline layout, the inflow of each riser heat exchanger is fully ensured to be relatively uniform.
Application case of coke oven riser heat exchanger
Currently applied in successful cases such as Shandong Special Steel, Fujian Sansteel, Handan Iron and Steel, and Wuhan Iron and Steel
Prospects for the transformation and promotion of achievements
The rising tube heat exchanger with alloy integral structure and self-cleaning coating has been successfully operated in a 4.3m tamping coke oven for nearly 4 years, proving that this technology is a mature technology that has been tested in practice and is suitable for 4.3m, 5.5m, 6m, top mounted or tamping coke ovens, and 7m top mounted coke ovens. The successful development of a new type of coke oven riser has solved the problem of waste heat recovery technology for coke oven raw gas, attracting widespread attention and great interest in the industry. It has broad application and promotion space in more than 400 domestic steel enterprises and nearly 2000 coke ovens in the coking industry, and is an effective way for coking enterprises to reduce costs, increase efficiency, save energy and reduce emissions.
