What type of pipeline is suitable for transporting hydrochloric acid over long distances?
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Our factory’s large tanks containing 30% hydrochloric acid are located 500 meters away from the workshop where it is used. We’re not sure which type of pipeline would be the best choice for transportation; ease of installation during construction also needs to be taken into account. Fiberglass is a good option, but it’s difficult to install, as it cannot be cut or welded easily； Plastic pipes lack sufficient strength, tend to deform easily, and their welds are prone to damage. Please discuss this – are there any other better types of pipes available?
Since 30% HCl is highly corrosive, and for process safety reasons, non-metallic pipes should be avoided as much as possible, as leaks can have serious consequences. Hastelloy C276 can be used; it has proven capable of withstanding corrosion from 30% HCl at room temperature. It is important to ensure good welding quality, as the welds and heat-affected zones are weak points prone to problems. Additionally, it is best to keep the operating temperature below 50°C. HCl storage tanks should preferably be filled with slightly pressurized nitrogen as an airtight seal. HCl solutions are much more corrosive in an oxygen-rich environment, and they can cause corrosion even in C276. If the project budget permits, a better Hastelloy B can also be considered.
It can be transported using steel-reinforced plastic composite pipes, and we have applied this technology in many chlor-alkali plants. Steel-reinforced plastic composite pipes offer pressure resistance and corrosion protection, especially against chloride ion corrosion. They are also strong, allow for easy cutting on-site, and are convenient to install – please give them consideration.
In terms of cost-performance, fiberglass-reinforced plastic is the best choice. Moreover, its installation is not as complicated as described by the original poster; the glass fiber pipe can be manufactured in sections and assembled on-site. What does it mean that one cannot cut and weld at will? The joints of fiberglass-reinforced plastic are also not made by welding. In my humble opinion, when non-metallic materials are an option, metal materials should not be chosen; firstly, they are expensive, and regardless of their corrosion resistance, they will still corrode. But non-metals are different; as long as the right choice is made and quality is ensured, corrosion will not occur. (There are damages caused by other reasons; this is not discussed here.)
The workshop where our company produces hydrochloric acid (30%) and the large storage tanks are located further away from you; originally PPH composite pipes were used, but some of them have since been replaced with steel-reinforced PE composite pipes. The reason is that the PPH composite pipes used in the production workshop often leaked due to aging of the pipe welds; later, most of them were replaced with PE composite pipes (for DN200 and below), which yielded better results. Therefore, the pipeline for transporting hydrochloric acid was also changed to PE composite pipe.
This post was last edited by yuchenchf on 2011-12-3 09:17. Reply to 1# zyc88882011: This issue can be easily resolved using steel-lined PTFE pipes; they are easy to install and have a long service life. Those interested can discuss it further
This post was last edited by gz19700215 on 2011-12-3 10:22. Advantages and disadvantages of PPH composite pipes and PE pipes when used with hydrochloric acid: 1. Ease of use – PPH composite pipes are superior to PE composite pipes in terms of ease of use; they can be cut as needed and used to create irregular bends, whereas PE composite pipes require bending at specific angles. 2. Welding reliability: PE composite pipes are superior to PPH composite pipes, as PE composite pipes have a larger area of electrofusion contact surface. 3. Strength: PPH composite pipes are better than those with wire mesh; PE pipes have strength similar to that of PE pipes with steel frameworks. 4. The temperature resistance of PPH composite pipes is superior to that of PE composite pipes. The fiberglass-reinforced pipe mentioned by the original poster is likely to be a PPH composite pipe, as such pipes have fiberglass wrapped around the outside of the PPH tube for reinforcement. Glass fiber reinforced plastic pipes are not suitable for hydrochloric acid and are mainly used in corrosive ductwork and similar applications.
Reply to 6# zhouxuelei: Thank you. Using steel-lined PTFE is problematic for long-distance installations, as it’s difficult to get the dimensions accurate
Reply to 8# zyc88882011: There should be no problem. Since everything is connected using flanges, how could there be any size issues?
Reply to 8# zyc88882011: Steel-lined PTFE pipes are relatively expensive, and they can only be connected using flanges; they cannot be used underground.
Reply to 8# zyc88882011: PFA pipes can be used; they can withstand a pressure of up to 6 kilograms, are resistant to HCL corrosion, and are available in rolls of 100 meters each. The price is a bit high; 1 inch costs over 200 yuan per meter