Returning from northern Shandong to discuss the use of gypsum in acid production
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I spent a few days in Wu Di; I just left northern Shandong today. The gypsum-based acid production process there is currently under major maintenance. Their acid production procedure involves external decomposition in kilns, followed by three-stage cyclone preheating, with purification carried out using a tower system. What he doesn’t understand is the conversion process – although it’s a two-stage conversion with two absorption stages, the way heat exchange is handled is quite different from other acid production processes. There are additional lines involved in the temperature increase during conversion, and he hopes that those who are familiar with this type of process can share their insights.
Can you be sure it’s “decomposition outside the kiln + 3-stage cyclone preheating”? This is a major breakthrough, but someone from Sanhuan also went in to take a look and said there was only cyclone preheating.
At that time, I also thought it would be difficult to achieve decomposition outside the kiln; I estimated that the maximum achievement would be preheating outside the kiln. I discussed this with my colleagues in Tangshan while I was in Zunhua, and they agreed that it was hard to accomplish such a thing. I still want to use off-kiln decomposition plus level 5 cyclone preheating.
I would like you to confirm whether external decomposition is used in northern Shandong. There is no further information available on the use of external decomposition by the German company Lurgi!
The flue gas generated during the production of acid from gypsum contains SO2, SO3, O2, N2, CO, CO2, etc. The SO2 content is low, and the two-stage two-absorption process cannot achieve self-thermal equilibrium; therefore, an auxiliary heating line is required for the conversion and heating process.
There is a temperature rise appendix, which I saw on site as well. Off-kiln decomposition is not available in northern Shandong for now.
It is a level-4 preheater kiln. Take a look at the Lubei patent made public on January 14, 2009 (200810139276.2; I tried to upload it but couldn’t find a way), and everyone will understand. This post was last edited by ltr on 2009-2-20 16:13]
I work in northern Shandong. Let me explain the principle: Our factory has two production systems, and the secondary line is connected to the exit of the fourth stage of the other system; this results in lower levels of sulfur dioxide emissions, while heat is made full use of. Additionally, the other system eliminates the need for diesel fuel used in waste heat recovery units. Do you understand? Oh, one more thing: the fourth heat exchanger in our factory is divided into A and B types, with two of them. If there are any issues, please contact ysgf2008@163.com
In northern Shandong, it should be excess heat outside the kiln + decomposition inside the kiln.
This post was last edited by in the blink of an eye on 2009-5-1 18:25. The people from northern Shandong have created a miracle; it’s important to protect this technology well.
Does LTR also know about those patents? Please let me know
The gypsum-based acid production project at our factory is about to be completed, and it utilizes level 5 cyclone preheating; we hope everyone can provide more information on this topic.
What is the approximate cost of producing acid from phosphogypsum? *e*e 8# People from northern Shandong
Without off-furnace decomposition technology, it is not successful yet
Off-kiln decomposition technology is very difficult to implement. The kiln-out decomposition technology for ordinary cement requires an atmosphere in the decomposition furnace that is incompatible with that used in gypsum acid production! ! !
This post was last edited by ltr on 2009-5-27 at 16:27. 11# zxy20060108: There are many patents related to the use of phosphogypsum for acid production. Here is the list: 1. 96116877.3 – Process for producing cement and sulfuric acid from phosphogypsum; 2. 93111802.6 – New process for producing potassium sulfate and ammonium chloride using phosphogypsum; 3. 01133566.1 – Method for producing barium sulfate and calcium chloride simultaneously from waste phosphogypsum; 4. 200710066431.8 – Method for reducing the decomposition temperature of phosphogypsum during sulfuric acid production; 5. 200810020289.8 – Method for drying granular phosphogypsum using sulfuric acid exhaust gas; 6. 200510021095.6 – Method for producing industrial sulfuric acid using phosphogypsum as raw material; 7. 200510022084.X – Production method for sulfuric acid using phosphogypsum waste; 8. 200710077609.9 – New method for producing sulfuric acid and cement from phosphogypsum; 9. 200610010792.6 – Method for producing cement and sulfuric acid using high-silica phosphogypsum; 10. 200710051599.1 – Method for producing wollastonite and sulfuric acid from waste phosphogypsum; 11. 200810068735.2 – Method for producing sulfuric acid using phosphogypsum as raw material; 12. 200810058324.5 – Method for producing calcium sulfate whiskers from phosphogypsum; 13. 200810058661.4 – Method and equipment for producing sulfuric acid and generating electricity by decomposing phosphogypsum through static reduction; 14. 200810068831.7 – Method for producing sulfuric acid and lime by decomposing phosphogypsum in a suspended state; 15. 200810069029.X – Method for producing potassium-calcium fertilizer and sulfuric acid using insoluble potassium-containing rocks and phosphogypsum. For more information, you can visit http://www.sipo.gov.cn/sipo2008/zljs/.