Corrosion issues of heat exchange equipment in chemical wastewater treatment
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I’m new to the chemical industry. I’d like to ask everyone: generally, how is scaling and corrosion in heat exchange equipment in this industry addressed? Are there any other surface protection methods used in addition to scale inhibitors and corrosion inhibitors for wastewater treatment? What specific methods will be used? Thank you all.
Ultrasonic scale prevention is a good option. Cathodic protection is also a good option!
Plate heat exchangers also develop scale over time, and they need to be taken apart for chemical cleaning. Even after long periods of use, shell-and-tube heat exchangers will normally develop scale, requiring the removal of the covers for high-pressure cleaning of the tubes.
The issue of scaling can be addressed through proper selection of the design; it is advisable to use shell-and-tube types, as their tubes and shells can be cleaned, making both physical and chemical cleaning methods convenient. It is also easy to introduce the medium to be processed into the tube section； If it is a heat exchanger at the pump outlet, try to increase the pump frequency; high flow rates help to delay scaling, or pulse operation can be employed ； To address corrosion, it is best to focus on the material used; heat exchangers made of carbon steel, stainless steel, titanium, graphite, or glass-lined materials should be selected depending on the type of medium involved.
The main task is to select appropriate materials based on the medium and operating conditions. For example, in cases where the chloride ion content is high, a graphite heat exchanger is an appropriate choice.
Indicators for installation temperature during import and export, connected to the DCS; a heat transfer coefficient is calculated on the DCS and displayed for the main operator, and cleaning is carried out when the coefficient drops to a certain level.
Thank you for your reply. I see that some companies carry out fluoride spraying; I was wondering if that is feasible
Thank you for your reply. Are you considering applying fluoride?
Thank you for your reply. Is the heat transfer coefficient measured by this DSC accurate?
It is calculated based on the inlet and outlet temperatures. When it was first put into use, there was a certain value; over time, you can see that value decreasing
Spraying is generally not recommended, nor is lining with plastic; for heat exchangers, this approach results in low heat exchange efficiency. To achieve the same level of heat transfer, a larger heat exchange surface area is required, which means the equipment has to be larger and the flow rate of the heat exchange medium must also be increased. In production operations, it is important to focus on energy savings, reduced consumption, less pollution, and improved efficiency. Of course, it’s not ruled out that some may have spraying or lining; after all, every piece of equipment can be non-standard