How to deal with a clogged crystal in a sulfuric acid pipe

Chemical fluids crystallize within the pipelines; the answer can be found by checking the relationship between \"pressure – temperature – saturated solubility\".

I haven’t worked with the persulfate process, but I personally wonder if it’s sulfur crystals? After all, the raw material is related to sulfur

If the pipe is short, it can be heated using a cutting torch; if it is long, it can be wrapped in torn burlap and doused in diesel before being heated. But be careful of fire.

Your acidity level is clearly off, so I have no choice but to take the risk.

At low temperatures, it’s as if the 93% acid is being concentrated into 98% acid; the freezing point of 98% acid is around 5 degrees. The ambient temperature has a significant impact on acid crystallization, and factories in the north should pay extra attention to this issue. What matters most when it comes to easy crystallization is the freezing point.

Using low-pressure steam or circulating water for pipe flushing, it seems the issue is still an incorrect acid concentration.

Last year, we had a lot of trouble here with sulfuric acid pipes that used steam for crystallization; 98% concentrated sulfuric acid crystallizes at 0.1 degrees, but the sulfuric acid in our case usually reaches 85% concentration before it crystallizes, as it does so at 7.8 degrees. To prevent crystallization from blocking the pipes, our backup sulfuric acid pump was constantly used to create backflow, and steam heating pipes could also be used

Detailed description of sodium hypochlorite: Physical and chemical properties – Solid sodium hypochlorite appears as a white powder, and it is extremely unstable in air. It decomposes rapidly upon heating, but remains more stable in alkaline conditions. Ordinary industrial products are colorless or pale yellow liquids with an effective chlorine content of 100–140 g/l. It is soluble in water to produce caustic soda and hypochlorous acid; hypochlorous acid then decomposes to yield hydrogen chloride and oxygen. Due to the strong oxidizing power of oxygen, sodium hypochlorite is a strong oxidizing agent. Its stability is affected by light, heat, heavy metal cations, and pH value, and it has a pungent odor. 　　Uses: Mainly used for the bleaching of pulp, textiles (such as cloth, towels, T-shirts, etc.), chemical fibers, and starch. It is used as a bleaching agent for fats in the soap-making industry. The pharmaceutical industry uses it to produce hydrazine hydrate, monochloramine, and dichloramine. It is also used as a chlorinating agent for the production of cobalt and nickel. Used as a water purifier, bactericide, and disinfectant in water treatment. The dye industry is used to manufacture Prussian blue sulfide. The organic industry is used to produce chloropicrin, a detergent for the hydration of calcium carbide to produce acetylene. Agriculture and animal husbandry use it as a disinfectant and deodorizer for vegetable and fruit farms, livestock sheds, and other facilities. Food-grade products are used for the disinfection of drinking water, fruits, and vegetables, as well as for the sterilization and disinfection of food manufacturing equipment and utensils. (Note: This is off-topic! ) This post was last edited by chx8965 on 2008-2-4 19:16 ]

This year, Hunan has experienced freezing rain and severe ice formation. When our acid pipes freeze, we use circulating water to spray on them; it’s very effective and speeds up the process. The temperature of our circulating water is around 20 degrees. :L

Previously, my factory also experienced sulfuric acid crystallization inside the cold exhaust pipes; the solution adopted was to use circulating water for spraying

Last year, most parts of the south were affected by rare low-temperature weather. Sulfuric acid equipment in the south was basically not designed with low-temperature effects in mind. Acid 98 crystallizes at 5 degrees. Just as the power grid in the north suffered little damage while that in the south was severely damaged. We should take into account the impact of extreme climates when designing. On one hand, bypass return is used, and on the other hand, appropriate insulation measures are employed (steam tracing pipes or insulation foam). Since it’s already blocked by crystals, just use steam to blow it out from the outside, or wrap it with straw ropes and pour some oil on it to burn it away. Be extremely careful to prevent fires! ! ! !