Tank bottom sludge separation

Tank sludge separation refers to the treatment of the sludge accumulated at the bottom of the oil storage tank to separate the oil, water and solid residue. Tank sludge is usually a mixture of crude oil, water, sediments (such as sand, rust, microorganisms, etc.) and possible additives, and is viscous and difficult to handle. Effective tank sludge separation is essential to ensure the safe operation of oil storage facilities, prevent environmental pollution and recover valuable resources. The following are the main methods and equipment for tank sludge separation: 1. Physical separation technology a) Gravity separation: - Initially utilize the density difference of the tank sludge itself, let it stand or use the inclined plate/inclined tube sedimentation tank to allow the heavier solid particles to settle naturally, and the upper part is an oil-water mixture. **b) **Centrifugal separation**: - Use a horizontal or vertical centrifuge to separate the solid and liquid phases in the tank sludge through the centrifugal force generated by high-speed rotation, and the solid particles are deposited on the inner wall of the drum, and the oil-water mixture is discharged through the center of the drum. c) Filtration separation: - Use filter press, belt filter and other equipment to intercept solid particles through filter media (such as filter cloth, filter screen) and allow oil-water mixture to pass through. 2. Thermodynamic separation technology a) Thermal distillation/thermal analysis: - Heat the oil sludge at the bottom of the tank to a certain temperature, and use the difference in boiling points of oil, water and solid substances to separate oil vapor and water vapor through a distillation tower or thermal analysis device, and then condense and recover oil and water, and the solid residue remains at the bottom. b) Pyrolysis/cracking: - In an oxygen-free or oxygen-deficient environment, heat the oil sludge at the bottom of the tank to a high temperature to crack the organic matter in it into oil gas, water vapor and solid charcoal. The oil gas is recovered as oil after cooling, the water vapor is condensed and recovered, and the solid charcoal is treated as residue. 3. Chemical/biological treatment a) Chemical demulsification: - Add demulsifiers to change the properties of the oil-water interface and promote oil-water separation. Then, physical separation technology can be used to further separate solid particles. b) Bioremediation: - Utilize the metabolism of microorganisms to degrade organic matter in sludge, reduce sludge viscosity, improve its treatability, and then use physical or thermodynamic methods to separate it. 4. Combined treatment process a) Three-phase separation: - For the mixed oil, water and solid phases of tank bottom sludge, a three-phase separator is used to separate the oil, water and solid phases at one time or in steps through gravity, buoyancy, centrifugal force, etc. b) Multi-stage treatment: - According to the characteristics of tank bottom sludge, a multi-stage separation process is designed, such as first using physical methods for rough separation, and then using thermodynamic or chemical methods for fine separation to ensure efficient separation of oil, water and solid phases. Equipment selection and application When selecting tank bottom sludge separation equipment, the following factors need to be considered: - Sludge characteristics: oil content, viscosity, solid content, composition complexity, etc. - Separation requirements: oil and water recovery rate, solid residue treatment standards, treatment cycle, operating cost, etc. - Site conditions: spatial layout, energy supply, environmental protection requirements, investment budget, etc. Common tank bottom sludge separation equipment includes: - Centrifuge: such as horizontal spiral unloading centrifuge, disc centrifuge, etc. - Filter press: such as plate and frame filter press, chamber filter press, diaphragm filter press, etc. - Pyrolysis furnace: including mobile and fixed pyrolysis devices. - Three-phase separator: suitable for sludge treatment with high oil content. - Chemical treatment equipment: such as demulsification reactor, agent injection system, etc. By rationally selecting and combining the above equipment and technologies, an efficient and adaptable tank bottom sludge separation system can be constructed to achieve effective sludge treatment and resource recovery. In actual operation, it is also necessary to regularly clean and maintain the oil storage tank to prevent sludge accumulation, optimize the operating process, and reduce the amount of sludge generated to achieve the best environmental and economic benefits.