The problem of sulfur foam in tannin desulfurization
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The problem of sulfur foam formation during the desulfurization of tannin is a major challenge for our company. Since we use Ende powder gasification furnaces, the gas contains a high level of dust, which contaminates the desulfurization solution used in the tannin desulfurization process and results in the formation of numerous very fine bubbles; in some cases, these bubbles even turn black. Even stirring does not seem to help much. I would like to ask those with experience whether it would be appropriate to add antifoam agents, and if so, which ones. Could you also suggest possible reasons related to an inappropriate liquid-to-gas ratio? I appreciate any guidance you can provide
Adding defoamer is not appropriate. If the dust content in the gas inside the gasification furnace is too high, the system solution will become too dirty, which may lead to the situation you mentioned. The situation may be even worse if the system is stopped and then restarted, as the consumption of solution and alkali in the system is also extremely high. If such a situation occurs during normal production, I believe it is necessary to take action in the following areas: First, it is important to maintain stability in the components of the system solution; the total alkalinity and the amount of tannin present should not be too low. Fresh alkali solution should be added to the system regularly throughout each shift, following the principle of adding small amounts multiple times. (Since you haven’t provided analysis of the solution, I’m not sure whether its components are appropriate.) ； II. Adjust the nozzle in the spray regeneration tank properly to ensure an adequate amount of regeneration air. Whether the amount of air is appropriate can be determined by checking the potential value in the solution; however, the amount of regeneration air should not be too large, as this can lead to over-oxidation ； III. It is necessary to ensure overflow; the regeneration of sulfur foam must not be forcibly suppressed ； IV. It is recommended to carry out technical upgrades to the dust removal system in the previous process in order to reduce the dust content in the gas ； V. The system circulation rate should not be too high; it should be adjusted so that the gas parameters at the outlet meet the specified standards ； VI. If the amount of foam is too large and cannot be controlled, the air inlet of the injector can be blocked for a short period of time; once the situation improves slightly, air should be allowed to flow in as soon as possible (the air inlet must not be blocked for an extended period).
1. Can the reactor be made in a smaller size? For example, by reducing the depth of the liquid, the likelihood of bubbling will decrease； 2. Stirring should be able to improve the problem of excessive foaming; it’s not clear whether it’s possible to increase the stirring intensity as long as the process conditions permit it ； 3. I think choosing the right surfactant should work
Agree to make adjustments based on the view from the second floor.
It is best to use a catalyst based on the cobalt phthalocyanine system, employing a dual-catalysis method. Many domestic companies use tannin combined with 888 dual catalyst. It works very well.
Our main problem is also related to the foam tank; I remember once the foam turned completely black and liquid leaked out, causing environmental pollution – it was quite serious. Therefore, the mixing ratio is very important, and perhaps the previous filter press would be a better option. :)
1. The main thing is to properly adjust oxidation regeneration. 2. Use an appropriate amount of titanium cobalt desulfurizer in combination with tannin, and the problem will be resolved after some time ； Because we have encountered this situation before.
From an overall process perspective, dust removal and temperature reduction during gas generation are the key points. As long as the dust in the gas generation process is removed, desulfurization is no longer a problem. I’ve never seen an Endu furnace, but I always feel that the problems that arise in a particular section should be solved there. The problem of gas generation cannot be resolved by desulfurization.
Adding defoamers is clearly not a good solution; it only addresses the problem temporarily. We need to find solutions at the source in order to reduce the dust content in the gas entering the desulfurization tower; if this level cannot be lowered, no amount of effort will make a significant difference. It’s also possible that the curing of the adhesive was not proper; it is recommended to increase the activation time and temperature, and wait until the entire adhesive mixture becomes clear before adding it to the system.