Selection of desulfurization and sulfur recovery processes for coke oven gas
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This post was last edited by Steven_p0kTk on 2023-11-20 09:03. In wet oxidation desulfurization, the sulfur recovery process is one of the key elements; its stable operation ensures a balanced output of sulfur, which in turn helps to maintain the stability of the desulfurization system. The HPF desulfurization process often employs a sulfur recovery method based on continuous foam sulfur melting, which has both advantages and disadvantages. Advantages are: (1) Continuous operation with low labor intensity required ； (2) The produced black sulfur can be sold as a product, possessing certain economic value ； The disadvantages are: (1) The sulfur melting tank is a pressure vessel, requiring strict management ； (2) Using foam for direct sulfur melting is equivalent to heating a large amount of desulfurization liquid, resulting in high energy consumption ； (3) A large amount of desulfurization liquid is heated and returned to the system, requiring a corresponding cooling system, which further increases energy consumption ； (4) The production process of the sulfur melting tank is strictly controlled and requires experienced operators; carelessness can lead to failure to melt sulfur or blockage of the clear liquid pipe, or even blockage due to deposits forming on the walls of the sulfur melting tank ； (5) Production is unstable due to steam and operational factors, affecting sulfur output. Different companies choose to use or avoid sulfur melting tanks based on their own needs. Some companies opt for plate and frame filter presses or centrifuges to produce sulfur paste, taking into account the various disadvantages of sulfur melting tanks, while other companies are forced to use such tanks due to the difficulties associated with disposing of sulfur paste. By taking various factors into account, Guoliutong combines these two approaches to leverage their respective advantages and introduces solutions for the utilization of sulfur resources. The sulfur resource utilization approach involves ultimately concentrating sulfur foam with a low solid content into a sulfur slurry with a high solid content, which is then fed into a continuous sulfur melting furnace for melting, thereby producing high-quality elemental sulfur. The advantages of this approach are: (1) Since the amount of desulfurization liquid entering the sulfur melting vessel is significantly reduced, the salt content in sulfur is greatly decreased, which improves the quality of the resulting elemental sulfur; its sulfur content can reach over 95% by weight, granting it greater economic value ； (2) The amount of desulfurization liquid entering the sulfur melting tank is significantly reduced, which lowers the energy consumption of the tank; as a result, approximately 80% of steam consumption can be saved ； (3) The amount of clear liquid decreases, reducing the impact on the desulfurization system when this clear liquid is returned to it; at the same time, blockages in the sulfur melting tank are less likely to occur ； (4) Each sulfur melting tank (taking DN1000 as an example) can achieve a production rate of 6–7 tons per day, which is 250% higher than that of direct sulfur melting using foam; there is no need to install a large number of such tanks as in traditional continuous sulfur melting processes ； (5) It is suitable for the situation of weak foam formation in desulfurization using complexed iron with coke oven gas, and it solves the problem of inability to produce sulfur in the sulfur melting tank due to weak foam. (6) The cost of renovation investment is low.
The selection of a desulfurization and sulfur recovery process for coke oven gas is a complex engineering problem; common methods include wet oxidation desulfurization and HPF desulfurization processes. For the key aspects of sulfur recovery in the wet oxidation desulfurization process, the main factors to consider include sulfur recovery efficiency, energy consumption, cost-effectiveness, operational convenience, and environmental requirements. Although the traditional foam continuous sulfur melting process has advantages such as continuous operation, low labor intensity, and certain economic value of the output, it also has a series of disadvantages, including strict requirements for pressure vessel management, high energy consumption, high technical demands on operators, and unstable output. Therefore, to avoid these drawbacks, some companies choose to use plate and frame filter presses or centrifuges for the production of sulfur paste, while other companies are forced to use sulfur melting reactors due to the difficulties associated with handling sulfur paste. To integrate the advantages of different processes, sulfur resource utilization solutions have been developed. This approach improves the quality of the resulting black sulfur by concentrating low-solid-content sulfur foam into a high-solid-content sulfur slurry, which is then melted, allowing the sulfur content to reach over 95% wt ； At the same time, as the amount of liquid entering the sulfur melting tank is significantly reduced, energy consumption is greatly lowered, which allows for substantial savings in steam usage. This reduces the impact of the liquid on the desulfurization system, lowers the risk of blockages in the sulfur melting tank, and helps to address the issue of weak desulfurization foam caused by complexed iron. This approach improves production stability, reduces operating costs, and requires relatively low investment in modifications. Enterprises should consider various factors based on their specific conditions and requirements, and select the most suitable sulfur recovery process. This includes factors such as raw material properties, desulfurization efficiency, equipment investment and operating costs, product quality, and environmental requirements. Generally, enterprises focus on selecting a process that can achieve a high sulfur recovery rate, operates stably, offers good economic benefits, and meets environmental requirements. .