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This post was last edited by Steven_p0kTk on 2023-8-10 09:31. The crystallization of elemental sulfur involves two processes: the formation of nuclei and the growth of crystals. These two processes occur almost simultaneously. If the rate of nucleus formation is greater than that of crystal growth, a large number of small sulfur crystals are formed; whereas if the rate of crystal growth is greater, fewer but larger sulfur crystals are produced. Under normal conditions, a higher system temperature and higher alkalinity result in a faster formation rate of sulfur nuclei. During the regeneration process, a small amount of the required gas dissolves into the liquid to carry out oxidative regeneration of the catalyst; the vast majority of the remaining gas rises within the tower as pressure decreases. When it rises close to or above the liquid surface, the gas breaks through the liquid film, and the elemental sulfur attached to this gas film aggregates and floats upward, before being separated via an overflow weir. If the gas membrane breaks prematurely or delayedly, elemental sulfur will sink or remain on the liquid surface, making it difficult to separate; this leads to issues such as rising suspended sulfur and abnormally large foam bubbles. Analysis of the causes of abnormal sulfur foam: (1) Insufficient or excessive blowing intensity results in the sulfur foam from flotation having a weak, flaky structure, making it difficult to separate. (2) The desulfurizer contains foaming agents. (3) Foaming substances brought in by tar, engine oil, and gases. (4) The filtered (residual) liquid or rainwater is recovered and reintroduced into the system. (5) It is caused by the viscosity increasing due to the desulfurization liquid having an excessively high or low temperature. (6) The load is low, there is little sulfur, and the mass is small, making it difficult to break the liquid film. Main treatment measures: (1) Control the regeneration blowing intensity at a reasonable level. Within this control range, adjust the volume of air for regeneration according to the thickness of the foam layer. Generally, in winter the foam layer thickness is about 300, while in summer it remains around 500. Of course, conditions vary under different operating circumstances; thus, specific adjustments should be made based on actual situations. (2) Certain foaming agents are incorporated into some desulfurizers; sometimes they are added separately, and the amount to be used must be determined based on the foam formation. (3) Optimize the impurity removal process at the gas inlet to minimize the introduction of tar and impurities. (4) Residual liquids, especially those from the sulfur melting tank, need to have their temperature controlled properly before they can be returned to the system; filtration may also be necessary. Rainwater contains many impurities from the ground, so it should be avoided from returning to the system whenever possible. (5) The temperature of the desulfurization solution should be controlled properly; for PDS desulfurization, it should generally not exceed 35°C, and for complexed iron desulfurization, it should not exceed 40°C. (6) An appropriate height-to-diameter ratio for the regeneration tank, as well as an appropriate width of the flow channels and a suitable slope, facilitate the proper overflow of foam. (7) At low load levels, appropriately control the overflow rate; foam storage may be necessary when required. (8) It is caused by multiple factors, and requires a multi-level, multi-perspective approach.