What is a scientific acid addition regime for ammonium sulfate?
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With the increase in coke oven production, a situation occurred recently where the resistance in the saturator reached 10,000 Pa. Analysis showed that this was caused by severe buildup of deposits on the walls of the saturator. What is a scientific approach to acid addition for sulfuric ammonium?
I’m not sure what your current acid addition system is like. Generally, the standard intervals for adding acid are 48 hours and 72 hours respectively. Based on your current situation, if each shift lasts 8 hours with a three-shift operation pattern, it is recommended to use an interval of 48 hours for acid addition; if each shift lasts 12 hours under the same three-shift operation pattern, an interval of 48 hours is also recommended. Each time acid is added, the acidity level can initially be set a bit higher at 8–10%; once the resistance decreases, it can be reduced to 6–8%. Additionally, it is necessary to determine whether it is the preheater resistance that has increased or the saturator resistance, and then take corresponding measures in each case.
Adopting a regular heavy-acid addition system is beneficial for the proper operation of systems in the saturated phase; generally, a combination of continuous acid addition and heavy acid addition is used. However, the resistance caused by the material accumulation on the side walls is relatively high, and it is also necessary to adjust the saturator temperature settings.
One more thing to note: What was said above is correct. Combining continuous acid addition with periodic acid addition is necessary; when adding acid periodically, it is essential to rinse each washing section of the saturator from top to bottom for 5–10 minutes. In winter or in northern regions, warm water should be used for rinsing these sections.
Excerpts from the operating procedures regarding the addition of acid to the mixture are as follows: Regularly carry out the addition of acid to the mixture and the preparation of the mother liquor. The operation steps are as follows: Acid is added to the saturator every 72 hours of operation, with a acidity level of 8 to 10%; after the acid is added, a large-scale circulation is carried out for 30 minutes before starting the preparation of the mother liquor. When preparing the mother liquor, start from the top of the saturator and wash each part of it from top to bottom using warm water, cleaning each area for 5 to 10 minutes. Then, add acid while preparing the mother liquor, and promptly remove the acidic tar from the full-flow trough. Measure the acidity of the mother liquor every 10 minutes, and add liquid until enough is available for one acid addition cycle, maintaining an acidity level of 4.0% to return to normal.
On the 6th floor, at your facility: Zhongjia acid, how often? Also, does your facility operate on a three-shift, two-shift system? Will frequent addition of acid accelerate the corrosion of equipment pipes, and will it cause damage to the gasket seals during the acid addition process?
The establishment of the acid addition system must take into account the actual production volume and the operating conditions of the equipment; it is not appropriate to simply adopt methods from other units. Short intervals between acid additions disrupt the normal balance of production, and there are also more leakage points. A long interval between acid additions can lead to blockages, insufficient mother liquor, or unplanned addition of water and acid, resulting in a vicious cycle of excessive mother liquor. Therefore, when formulating an acid addition system, it is best to create a comprehensive system that takes into account both the consumption of mother liquor and the operation status of the equipment. It is very important to adjust and determine one’s own acid addition system based on the existing one. When adding acid at a high concentration, it is also necessary to consider from which location water should be added. It is recommended that facilities with high preheater resistance use warm water for flushing through the preheater’s exhaust pipes, with the water then being discharged promptly into the large tank via the drain pipes. Solve the problem of high preheater resistance. It also applies to acid removers.
Another point raised is that, in addition to proper implementation of the acid addition procedure, the high resistance to material accumulation on the sidewalls of the saturator may also be due to issues with the position of the nozzles or poor circulation.
For acid addition, the interval is generally 48 hours. Our shift schedule is four shifts per day with three rotations of 8 hours each; some units use a four-shift schedule with two rotations of 12 hours each, in which case the interval between acid additions is 72 hours. The establishment of the acid addition system should be determined by taking into account the actual amount of gas to be treated as well as the condition of the equipment; since all sulfuric acid pipelines are equipped with flange guards, gasket damage hardly occurs. It is recommended that you install guards at the flanges of the sulfuric acid pipelines to reduce the risk of acid leaks causing harm to the workers.
A saturator is regularly fed with acid once a day for 24 hours; when adding acid, a acidity level of 4–10% is sufficient. Remember to rinse after adding acid. In this case, the saturator generally does not get clogged.
Floor 11 mentioned that the 24-hour saturator should have acid added to it once. The saturator isn’t clogged, but I’m wondering what the effect of crystallization is, whether the level can be maintained stably, and if there’s an increase in corrosion. I hope Floor 11 can respond.
Adding acid once every 24 hours – isn’t that too short an interval, which could accelerate corrosion?