Proper sulfur recovery has a significant impact on the desulfurization system

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Desulfurization is a complete system, and the sulfur recovery part of this system has a significant impact on the overall operation of the system. In simple terms, the processing capacity of the sulfur recovery unit determines the amount of sulfur that can be removed. To ensure the proper operation of the sulfur recovery process, the following points can be considered: 1. It is necessary to determine whether the buffering time of the foam is sufficient; 2200,000 tons of coking desulfurization waste involves the use of filter presses to handle the sulfur foam. The working principle of a filter press is a physical pressing process: in the first half of the cycle, the resistance to feeding material is low, so the feeding rate is fast; but in the second half, this resistance increases, causing the feeding rate to slow down and the processing capacity to decline gradually. However, the amount of foam that overflows from the regeneration tank remains constant. As the filter press’s ability to handle foam decreases, more foam accumulates in the intermediate tank for storing foam, which leads to an accelerated rise in the liquid level in that tank. For each filter press in this factory, the feeding time is 3 hours, while the blowing and unloading time is about 1 hour. Based on this, the foam tank needs to have a capacity to store foam for at least 1.5 hours. Based on a current foam overflow rate of 30 m3/h, the effective volume of the foam tank needs to be 45 m3. The total volume of the existing foam intermediate tank is 23 m3; considering that in actual operation a foam tank can generally only be filled to 80%, the actual available space is only 18 m3. As a result, the foam buffering time is far insufficient, which leads to frequent overfilling of the foam tank in this device and also puts significant pressure on the workers operating it. Another example is a coking desulfurization project with a capacity of 1.3 million tons; in this case, slab-based treatment is also used for the sulfur foam, and two vertical foam tanks equipped with agitators of φ3.8*5.46 are employed. The buffering time of the foam is over 2 hours, and there is virtually no occurrence of foam escaping from the tanks. 2. Is the feeding time of the filter press sufficient? How can one determine whether the filter press is full? A diaphragm pressure gauge is usually installed behind the inlet valve of the filter press; in better-equipped units, a pressure transmitter is also used. The pressure reading of the filter press serves as its \"eye,\" providing an intuitive indication of its operating condition. When this pressure reaches a certain value, it indicates that the filter press is full and it’s time to discharge the material ； To what extent should the pressure rise time gradually shorten before it’s time to replace the filter cloth? All these on-site operations rely on pressure as a guide. 3. What is the appropriate opening degree of the outlet valve of the foam pump? How should this degree be determined during operation? In a certain coking plant, the motor connected to the foam pump tends to experience overcurrent during operation; once the outlet valve is opened to a certain extent, the motor is prone to tripping. In actual operation, operators often keep the outlet valve of the foam pump closed to prevent it from tripping; as a result, the pump does not trip, but it never achieves its maximum pumping capacity. Some adjustments were made: the control panel with current display was modified, and in actual operation more attention is paid to the operating current of the foam pump, so as to ensure that the pump operates at its maximum capacity without exceeding the current limit. Additionally, the start/stop indicator for the foam pump is connected to the DCS interface, allowing for constant monitoring of the pump’s operating status. The operation was basically balanced thereafter. The above three points—taking into account the storage volume of the foam tank, the pressure display of the filter press, and the monitoring of the current meter on the foam pump—are aimed at optimizing the processing capacity of the sulfur recovery unit, enabling operators to control the filter press and the foam pump more easily, reducing their workload, and increasing the upper limit for sulfur recovery. Ultimately, this brings sulfur recovery to its optimal operating condition. In this way, ensuring a balanced output from the desulfurization system guarantees stability at the upstream stage.