The objective of chemical treatment is to change the surface charge of either the gas bubble or the oil droplet in order to cause adhesion between them after collision. The size ratio of the bubble-to-oil droplet is usually <1:1. The only solids that are floated are those whose surface charge is opposite to that on the bubble surface, or those that are associated with, and contained in, the oil droplet. For this reason, induced processes may only remove 55-75% solids from the forward flow as compared with 95-98% oil droplet removal. No attempt is made to flocculate oil droplets and solid particles, because the mixing intensity in the units will tend to break up any floc structure that has been formed.

In general, oil droplets and other suspended material will be negatively charged. Addition of cationic polymer neutralizes the charge on the oil-gas species, while a long-chain polymer collects the contaminant in preparation for removal. Most cationic polymers work best in the pH range 6-9. If the pH falls outside this range, pH adjustment of the wastewater may be required. Overall removal rates are around 90% without chemicals up to 98% with chemicals. In order to size a unit for commercial use, laboratory studies are conducted to determine the effect of variables such as rotor speed, chemical addition and feed rate on oil removal, all of which have an impact on the rate constant K. The data are then fed into proprietary models based on the Klimpel model, which contain correction factors for scaling up the equipment. The models have been validated using numerous sets of data from commercial installations. Oil-water separation is enhanced by using an emulsion breaker, a cationic high charge density, low molecular weight coagulant polymer. The polymer is distributed throughout the continuous (water) phase where it neutralizes the anionic charge at the oil-water interface. This destablizes the emulsion, allowing oil droplets to coalesce by collision with one another.

Cationic solution polymers would usually be applied as a 1-10% solution with a dose rate of 2-30 ppm. Emulsion polymers (tightly coiled polymer molecules entrapped in solvent, activated by dilution in water) are applied at concentrations no greater than 1-2% at dose rates of 0.5-5.0 ppm.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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