Oily sludge is generally composed of water-in-oil and oil-in-water emulsions and suspended solids. Most sludge particles are "oily solids" (such as asphaltenes, colloids and paraffins, etc.), and the density difference with water is small. , High moisture content and strong water holding capacity. Due to the large amount of chemicals used in the upstream production system of sewage treatment in refining and chemical enterprises, the composition of oily sludge is complex, and the sludge is seriously emulsified and difficult to settle. The oily sludge is relatively large in volume. If it is directly discharged without treatment, it will not only occupy a large amount of cultivated land, but also be accompanied by the production of foul gas, and will also cause pollution to the surrounding soil, water and air. The sludge also contains a large number of pathogenic bacteria, parasites (eggs), heavy metals such as copper, zinc, mercury, salts, and toxic and harmful substances that are difficult to degrade such as polychlorinated biphenyls, dioxins, and radionuclides.
Among them, oily sludge in refining wastewater treatment has been classified as hazardous solid waste for management. With the increasingly strict environmental protection requirements, its harmlessness, reduction and resource utilization have become an inevitable development trend, and sludge dewatering is the premise of sludge disposal. Oily sludge produced by refining and chemical enterprises is classified as hazardous waste. The water content of oily sludge before dewatering is 99.8%. A company conducts mechanical dewatering through a decanter dewatering industrial centrifuge to reduce the water content to less than 70%. Due to the complexity of chemical additives in the upstream production of refining and chemical enterprises. The sludge is seriously emulsified and difficult to settle. Reducing the moisture content of the sludge can reduce the equipment load and processing difficulty of the subsequent sludge treatment, and significantly reduce the subsequent disposal costs.
The sludge concentration is too low to effectively flocculate, and the decanter industrial centrifuge will be carried out with the dewatered sludge, thereby affecting the sludge moisture content. If the sludge concentration is too high and exceeds the processing load of the machine, the effect of chemical treatment will be reduced. Therefore, the sludge concentration should be controlled within a certain range as much as possible to achieve a stable treatment effect. Due to the material principle of centrifugal dewatering, the lower the rotation frequency of the main engine, the lower the rotational speed, and the lower the moisture content of the sludge. With the increase of the frequency of the main engine, the moisture content of the sludge increases, and the treatment effect decreases. On the premise of ensuring material transportation, the speed of the main engine should be reduced as much as possible for oil-water separation. So as to obtain greater processing benefits.
(1) Ore processing industry: kaolin and calcium carbonate processing, bentonite and titanium dioxide production.
(2) Petroleum and natural gas exploration and petrochemical industry: oil and natural gas exploration, crude oil refining and related industries, lubricant additives and waste oil recovery.
(3) Decanter industrial centrifuge Organic chemical industry: intermediate products and result products of organic chemistry.
(4) Polymer industry: thermoplastic materials including PVC, polypropylene, polystyrene, synthetic rubber and fibers.
(5) Inorganic chemical industry: fertilizers for bleach, acid, and silica products.