What material should be used for pipes in ammonia chloride media?

Plastic pipes are the best choice for this purpose; steel pipes, whether made of stainless steel or carbon steel, are not suitable due to the high levels of chloride ions, which cause severe corrosion. Plastic pipes work well in this context.

Is the pressure resistance of plastic pipes sufficient? 7.8Mpa is quite a high pressure! Use plastic lined with steel

I want to know what the pH value of this ammonium chloride is; it’s necessary to determine whether it is acidic or alkaline. If it is alkaline, carbon steel or stainless steel can be used, but this will result in a small amount of iron ions entering the solution. If it is acidic, then such materials cannot be used, and plastic pipes are also not suitable under high pressure conditions; steel-lined pipes could be an option.

A 6% ammonium chloride solution is highly corrosive; it does not perform well when used with stainless steel, carbon steel, or titanium. Plastic pipes can be used at low pressures, but the temperature cannot be high

For high temperatures and high pressures, a steel-lined PTFE option is suitable

For an aqueous solution of 6% ammonium chloride, it is a salt of a strong acid and a weak base; its pH is clearly acidic. Therefore, carbon steel pipes are definitely not suitable for use； Again, due to the high pressure, which reaches 7.8 MPa, plastic pipes are not suitable either; even pipes with plastic lining cannot be used, as the connection seals are prone to deformation under high pressure, leading to leaks ； As for stainless steel, a 6% solution already contains 60,000 mg/L of salts, including Cl ions, which causes severe corrosion of stainless steel; therefore, it is not suitable for ordinary stainless steel either ； For different grades of stainless steel, there are varying ranges suitable for different salt contents in water: 316 stainless steel (with a carbon content of less than 0.08%) is suitable for TDS levels of 2000–5000 mg/L; 316L stainless steel (with a carbon content of less than 0.03%) is suitable for TDS levels of 5000–7000 mg/L; 904L stainless steel (with a molybdenum content of 4.0–5.0%) is suitable for TDS levels of 7000–30,000 mg/L; and 254 SMO stainless steel (with a molybdenum content of more than 6.0%) is suitable for TDS levels greater than 30,000 mg/L.

At normal pressure, polymer materials are generally used, and the following are all very suitable: ABS plastic; EPDM; Epoxy; Fluorocarbon (FKM); LDPE; Natural rubber； Polycarbonate; however, since the pressure is 80 atmospheres, it is still feasible to use a steel lining. Last edited by fj170530 on 2009-2-13 at 15:55.]

Is there a flange for steel-lined PTFE? How to weld

Titanium materials should work; besides, is the pressure that high?

The titanium material we use currently doesn’t perform well; it often corrodes and leaks, especially at the welding points

The fluorinated lining version comes with flanges, and no welding is required on site. The pipes are measured on site, after which the manufacturer applies the fluorinated lining to both the pipes and the flanges, followed by installation on site; however, it’s not clear what the pressure level is

You can simply use pipes lined with PTFE. The key is to measure the pipe dimensions accurately; the manufacturer then prepares the lining and installs it on site. Moreover, the length of the pipeline should not be too great, otherwise the lining is prone to bubbling and damage under high temperature and pressure. There is a company in Zhejiang that specializes in producing such products. It seems to be called “Zhao Fulong””

I’m not aware of the concentration of ammonium chloride at your location. If the purpose in water treatment is to maintain the level of residual chlorine, then using UPVC drinking water pipes is sufficient; they are relatively inexpensive, easy to install, and do not cause secondary pollution. The water treatment industry here now uses this type of pipe material

Our company’s process involves concentrating dilute ammonium chloride using reverse osmosis membranes, and then evaporating the concentrated ammonium chloride. I asked my supervisor about those lined with PTFE; they were used over a decade ago, and due to the high temperatures the pipes stuck together. Ceramic ones work okay, but they can’t withstand impacts. The porcelain chips off in just a few days

Hello! What material did you change to later? Thank you!

Steel pipes can be used with our 711 anti-corrosion coating applied to them