On the application of waste acid concentration circulation pumps
Thread Content
This post was last edited by Mo You on 2020-9-19 at 15:53. Hello, experts. I’m a complete novice in this field, and I would like to ask for some advice: 1. At my previous workplace, we designed a system for the negative-pressure evaporation of phosphates; back then we used stainless-steel forced circulation pumps, but the seal problems were difficult to resolve, so we gave up using forced circulation. 2. For the treatment of waste acid in the facility, negative-pressure evaporation is also used for the first stage of evaporation. Currently, a natural circulation, that is, a thermodynamic cycle, is employed; however, the flow rate of the material through the heat exchanger is too low, which leads to frequent blockages in the tubes ； 3. In summary, I would like to ask: For forced circulation pumps used with high-risk materials, are there any pump seals that can be more durable, or is it possible to eliminate dynamic seals and use static seals similar to those in magnetic pumps? The forced circulation pump is normally operated 24/7; how can stability be ensured? How should one choose such options in highly corrosive environments?
Is forced circulation needs justification? What is the processing capacity?
It’s not a matter of argumentation; it’s a problem of forced circulation in this pump selection； There have been accidents in which people were injured due to leaks from pumps of this type used in the past.
We have the idea of changing it to a forced circulation system, but we have concerns regarding pump selection
Whether a particular pump is suitable depends on specific operational parameters: flow rate, head, type of fluid, density of the fluid, viscosity, operating temperature, and so on. Only after considering these factors can an appropriate pump model be selected. It’s impossible to simply say it’s a forced circulation pump – after all, who knows what your specific operating conditions are? Without that information, only general statements can be made. . . .
You might not have understood what I mean. I am aware of pump selection; what I want to know is the sealing issue related to pumps chosen for acidic, highly corrosive waste acids under negative pressure conditions.
Since it is a forced circulation system, both the inlet and outlet are under negative pressure; the pressure is already balanced. All that needs to be considered are the pump type, flow rate, head, and material. Unless it is transferred from a negative-pressure to a positive-pressure or atmospheric-pressure container, more considerations are required.
The flow rate of the forced circulation pump in the spent acid concentration system is usually very high, while the head is not that high. The selection primarily takes into account issues such as impeller corrosion and wear, as well as seal leakage. The price will be relatively high. The negative pressure issue is likely not the main cause of the seal leakage; as long as the material used for the seal is of proper quality and the cooling water pressure is maintained, the failure rate remains acceptable. PS: What is the maximum negative pressure that your system can achieve? The forced circulation pump is installed at a lower level, usually about ten meters away from the liquid level of the evaporator. If the mechanical seal leaks, air will not be pumped up, which would affect the cooling of the mechanical seal. The high-silicon cast iron pumps manufactured by some companies in Dalian can still operate stably in such applications. It is recommended to learn about the pumps produced by Dalian Hailida.