Problems caused by the reduction in coking desulfurization stages and improvement measures

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At present, in many of our industrial applications, two-stage or multi-stage desulfurization is used. However, considering issues such as reducing energy consumption and improving economic efficiency, many companies are considering reducing the number of desulfurization stages and minimizing the number of desulfurization towers. When enterprises adopt two-stage or multi-stage desulfurization, each desulfurization tower can be assigned a different load to balance production, enabling efficient economic operation, strong risk resistance, stable production conditions, and the assurance of continuous production. During single-stage desulfurization operation, in the event of emergencies or disruptions in system conditions, hydrogen sulfide levels experience significant fluctuations, along with various other problems. In the face of these issues, experienced technical service personnel will take appropriate measures: First, regarding the equipment: (1) Ensure that a backup unit (mother liquor pump) is available, and conduct regular inspections and maintenance on it to prevent fluctuations in hydrogen sulfide levels due to the lack of a backup unit. (2) The standby tower (desulfurization tower) should be inspected and maintained in a timely manner; after maintenance, it should be kept on standby. This ensures that it can be put into service promptly in case of process fluctuations or load adjustments, thereby maintaining process stability during production. II. Process aspects: (1) GLT complexed iron can improve the desulfurization efficiency of a single tower, but it is necessary to consider whether the regeneration system is suitable; the desulfurization capacity should be determined based on the suitability of the regeneration system. (2) By adjusting the system, ensure the timely flotation and treatment of sulfur foam to achieve sulfur balance. When the desulfurization stage is reduced, the sulfur content per unit of solution increases; it is therefore essential to maintain a precise sulfur balance in order to control the suspended sulfur and prevent its deposition. (3) It is necessary to determine the minimum circulation rate under specific loads to ensure that hydrogen sulfide levels remain within acceptable limits. When the desulfurization stage is reduced, the circulation rate decreases by a factor, which means that the sulfur capacity per unit of solution increases by the same factor. It is necessary to adjust the circulation rate according to actual conditions to meet the required standards. (4) Adjust the temperatures of the gas entering the tower and the desulfurization liquid to keep them within the specified ranges, in order to prevent fluid loss in the system due to large temperature differences. When the desulfurization stage is reduced, the amount of liquid stored in the system is drastically decreased; as a result, the system’s buffering capacity is greatly weakened. At this point, it is necessary to strictly control the temperature of the desulfurization liquid and maintain water balance. (5) The single-tower desulfurization system has low resistance and high flow velocity; it carries a relatively large amount of liquid. The liquid return pipe at the discharge port should be emptied frequently, and the returned liquid can be recycled, without causing any impact on the production in subsequent stages. (6) After the desulfurization stage is reduced, it is necessary to find a suitable catalyst concentration again; it should neither be too high nor too low. A too-high catalyst concentration represents a waste, while a too-low one hinders the removal of hydrogen sulfide. (7) The pretreatment of gas is effective; organic substances such as dust and tar are kept within specified limits, which is more conducive to single-tower desulfurization operation.