Antifoams or defoamer agents prevent and destabilize foam formation.
Foam formation in petrochemical processes may lead to significant problems. It is a physical incorporation of gas bubbles within a liquid solution. Foam formation occurs at the gas-liquid interface. A low surface tension liquid allows the surface of a gas bubble to expand easily. Hydrocarbons, small particles and acids will increase the foam formation tendency and stability. Negative impacts of foaming are reduced throughputs, overhead losses and separation problems.
Affected are separation drums, distillation columns, extraction units or gas and liquid scrubbers. Acid gas scrubbers in ethylene plants are very prone to foaming. There foaming is often related to fouling problems. Solid polymer particles can stabilise the foam. Foam formation can increase the differential pressure. Negative effects are emulsions in the water wash section or unwanted salt carryover into downstream equipment. So foaming can become far more severe if polymerisation is a problem. Extractive distillations sections of butadiene recovery systems often suffer from foaming problems. Some foams show a very high stability. High film elasticity, high surface and bulk viscosity are foam stabilising factors. High solids content can also stabilise foams. They will accumulate at the liquid/gas interface. That prevents bubbles from coalescing and bubble rupture.
Immediate action is required to prevent or destabilize existing foams. Defoamers or antifoams are chemical programmes, used for foam control. Antifoams prevent the formation of foams. Defoamers destroy already formed gas bubbles. A rupture of the film occurs because of a decrease of the surface area. This causes a large change in surface free energy. The result is the bursting of the bubble wall and is controlled by the “Marangoni Effect”.
Kurita´s antifoams or defoamers are surface active agents (surfactants). Our antifoams and defoamers meet the process requirements. Our highly efficient antifoams and defoamers destroy already existing foam immediately. A new formation of foam is prevented. Kurita ´s foam control programmes show rapid dispersion properties and chemical inertness. They have a lower surface tension than the foaming medium. Insolubility of the antifoam agent is very important for foam control. Our chemical programmes combine both functions to control foam formation. They have a very low solubility in the liquid solution. They enter the gas/liquid interface and concentrate at the surface film. This increases the elasticity of the liquid film on the gas bubble. Foam disruption forces allow the gas bubbles to rupture.
Kurita provides different types of foam control programmes. In petrochemical plants mainly silicone oils, organic or non-silicone antifoams are used.
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