Description of the hydrochloric acid desorption process pipeline
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This post was last edited by sunjl1981 on 2013-1-6 at 23:25. To those of you who have experience in the hydrochloric acid desorption industry: in this process, the temperature of the materials is relatively high. Our company currently uses pipes lined with PP along with rubber gaskets. What are the advantages and disadvantages of this approach? How can it be improved? # ， ， &
The pipeline materials used for hydrochloric acid distillation in our factory are carbon steel lined with F4, or carbon steel lined with graphite. Such pipeline materials can effectively address the issues of high temperatures and acid corrosion. However, when it comes to carbon steel pipelines lined with graphite, it is essential to handle them carefully during transportation and installation to prevent the graphite lining from breaking. When purchasing these lined pipelines, precise measurement is necessary, especially for the final adjustment section; inaccurate measurements can lead to difficulties in installation. As for gaskets, our factory also uses rubber ones, and no problems have been observed with them. Regarding PP-lined pipelines, the key is to check the temperature resistance of the PP material.
The general temperature tolerance limit for PP is around 80 degrees; high-density PP can withstand higher temperatures... Steel-lined PTFE seems to be a good choice...
We are working on this project and plan to use F4 pipes with a steel lining; F4 gaskets are suitable. Rubber gaskets aren’t very effective as they tend to age quickly. In any case, since it’s a pipe with a steel lining, using F4 gaskets is a good choice.
Can’t it be CPVC? It can withstand temperatures up to 100 degrees, and it’s probably cheaper than ones lined with PTFE.
Our factory has used CPVC, and over time deformation is inevitable; if it is to be used, pipe supports must be properly designed.
In fact, the fiberglass industry is developing well at present; acid- and heat-resistant fiberglass can be used, offering good performance in terms of both cost and durability.
For temperatures above 80°C, a steel-lined PTFE lining is used, along with PTFE expansion joints installed according to the pipeline layout; for temperatures below 80°C, steel-lined PP, UPVC, or other materials can be used.
Reinforced polypropylene pipes are generally used, but bellows compensators must be considered; otherwise the pipes will tear
Choosing gaskets can be tricky. Rubber-coated gaskets provide good sealing performance, but they tend to age quickly and become ineffective after just half a year, while F4 gaskets are also prone to leaks. A manufacturer in Taiwan said that their F4 tubes don’t require gaskets. Does anyone know for sure?
Use steel lining with PTFE, and install PTFE expansion joints according to the pipeline layout.
I’ve seen steel-reinforced polyethylene plastic composite pipes; they seem pretty good.
Steel-lined F4 can be used, and molded F4 can be employed for the high-temperature sections; meanwhile, care must be taken during operation to ensure that the system does not develop negative pressure as a result of cooling. For steel-lined F4, custom sizes should be used as much as possible to reduce spare parts.