Issues regarding thermal nitrogen purging during the shutdown of sulfur recovery units
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As environmental standards become increasingly stringent, the problem of excessive sulfur dioxide levels caused by sulfur injection during the shutdown of sulfur recovery units has become more and more prominent. Some facilities have adopted a hot nitrogen purging process to address this issue. However, due to the long purging time and the large amount of nitrogen required, coupled with the fact that all equipment needs nitrogen during shutdown periods, there is often a shortage of nitrogen. I wonder if any of you colleagues are facing similar problems? How to solve it?
Normal shutdown sulfur purging is carried out using incompletely burned inert gases; nitrogen is only used for purging the furnace tip, and the amount used is relatively small. If control is required, prior to stopping the operation, heat infiltration should be carried out in advance to raise the inlet temperature and reduce the accumulation of sulfur on the catalyst. If sulfur removal is not effective enough, it is likely due to a high outlet temperature of the cooler, or a large pressure difference between the inlet and outlet, which results in poor condensation and allows sulfur to enter the incinerator.
As far as I know, thermal nitrogen desulfurization is a patent of Qilu Institute
It seems this is a patent of Qilu Hospital
What I mean is how to address the issue of the long time and large amount of nitrogen required for thermal nitrogen purging.
Thermal nitrogen cycle sulfur blowing can be considered.
If the normal flow rate of the process gas is over 2000, then how much nitrogen is required for thermal nitrogen desulfurization?
Hot nitrogen purging for sulfur removal during shutdown requires several conditions for sulfur handling units: 1. Sufficient nitrogen supply (8,000 m3/h); during shutdown, nitrogen is in short supply throughout the plant, and this requirement is usually not met. 2. It has a medium-pressure steam heating source. 3. There are heat exchange equipment with a large heat exchange area. 4. The plant is equipped with two or more sulfur processing units; one unit is shut down while the other is in operation. After sulfur injection, the hydrogenation off-gas system comes online, and the hydrogen sulfide is sent to the other sulfur processing unit. 5. Qilu Petrochemical has employed superheated nitrogen for sulfur removal, and information on this topic is available at sulfur-related conferences and technical exchanges.