Heat exchanger material issue
Thread Content
The heat exchangers in our plant’s wastewater treatment station get clogged frequently; is it related to the material used? It is a sodium sulfate crystal; it has high hardness and strong adhesion. To clean it, the heat exchanger must be disassembled and steamed slowly. What material does not allow salt to adhere to it?
You need to provide detailed information about what materials are used, what type of heat exchanger structure it is, and so on, so that we can help you
What sewage? Is a heat exchanger also needed? To prevent sticking, one has to coat it with non-stick material; I’m not sure how effective that will be. In the past, we used them for the cooling coils in our crystallization tanks (for phosphate crystals), and the results were average.
I think, when it comes to salt deposition and blockage in heat exchangers, we need to consider ways to reduce crystallization from a process perspective; relying solely on material choices seems insufficient to solve the problem!
Crystallization is related to the properties of the process medium, operating conditions (flow rate, temperature), etc., as well as the roughness of the heat exchange tube walls.
Agree with the view on the fourth floor; the technical approach is more practical.
The problem of blockage in the heat exchange tubes can be delayed by increasing the flow rate in the tube side and enlarging the diameter of these tubes
Made of acid-resistant stainless steel tubes, using a floating-head heat exchanger, 304, 316L
In a floating-head heat exchanger, the tube sheets at both ends are not connected to the shell; the end that is not connected is called the floating head. When the tubes are heated, the tube bundle together with the floating head can expand and contract freely along the axial direction, completely eliminating thermal stress. Features: complex structure, high cost, easy to clean and maintain, completely eliminates thermal stress, and is widely used.
It mainly involves production wastewater that is neutralized after pickling; it contains about 20% sodium sulfate. After treatment, this water is used as circulating water, so parameters such as COD are not relevant. The heat exchanger is of the tubular type and is used primarily for preheating. The water that has been preheated enters the evaporator where it is heated further until it boils, and the steam is removed using vacuum.
Our sodium sulfate-containing wastewater is generally discharged directly into the biochemical treatment process for the recovery of mirabilite； This wastewater must be heated to high temperatures to maintain its fluidity. It is recommended that the poster collect the materials first and then treat the wastewater