How to Select Defoaming Agents for Water Treatment in Chemical Plants
1. Insoluble or insoluble in foam solution
In order to destroy foam, defoamer should be concentrated on foam film. For the state of defoaming agent, it should be concentrated and aggregated in an instant, and for the state of foam suppression, it should always be maintained in this state. Therefore, the defoaming agent is in a supersaturated state in the foaming liquid, and only insoluble or insoluble can easily reach the supersaturated state. Insoluble or insoluble, which tends to accumulate at the gas-liquid interface and concentrate on the bubble film, giving full play to its role at lower concentrations.
Low volatility and long action time
The premise is to determine whether the system requiring the use of defoamers is a water based system or an oil based system. For example, water-based systems require water-based defoamers and organosilicon defoamers. Oily defoamers, such as polyether modified silicon or polyether, are used in oily systems.
3. Have a certain affinity with foaming liquid
Because defoaming process is actually a competition between foam collapse speed and foam production speed, defoamer must be able to quickly disperse in the foaming liquid, so as to rapidly develop a wider range of foaming liquid. In order for the defoamer to diffuse faster, the active component of the defoamer must have a certain affinity with the foaming solution. The active component of the defoamer is too close to the foaming liquid and will dissolve; Too sparse to disperse. Only suitable for intimate relationships can be effective.
4. No chemical reaction with foaming liquid
When defoamers react with foaming liquid, they not only lose their efficacy, but also form harmful substances that affect the growth of microorganisms.
5. The surface tension is lower than the foaming liquid
Only when the intermolecular force of the defoamer is small and the surface tension is lower than that of the foaming liquid, can the defoamer particles penetrate and expand on the foam film. It should be noted that the surface tension of the foaming solution is not the surface tension of the solution, but the surface tension of the auxiliary foaming solution.