3.7. Utilization technology of oil sludge


The need for fuel oil storage tank sludge disposal due to the accumulation of sludge deposits in the bottom part of the fuel oil storage tanks. Resetting of sludge leads to significant environmental contamination by organic compounds, and the removal and reclamation  of sludge by third parties are associated with significant costs. At the same time burning sludge leads to fuel economy, since caloric content of sludge is close to heating oil and fuel oil storage tank is located in one to 5-7% of such deposits.

Features of the developed technology

The described technology to reduce pollution in the purification of fuel oil storage tank sludge to dispose of this sludge as a fuel, to increase the working capacity of the fuel oil storage tank. The technology involves grinding sludge by rotary-pulsation apparatus (RPA), admixed of fuel oil, to the crushed mass homogenization by cavitation apparatus (HCA) and the burning of a conventional liquid fuels. The figure shows the general flow diagram of processing sludge. The slurry from the vessel is loaded into the receiving hopper of the extruder with a hollow screw which supplies RPA. RPA and the extruder form disintegrator. In disintegrator via oil pumped from the container.

Thus, grinding sludge in the disintegrator is in the presence of heavy fuel oil, with crushed slurry by stirring with fuel oil at a ratio of ~ 1:20. RPA is a conical mill rotor surface has longitudinal slots. The rotor rotates within the stator having the same shape and the longitudinal slot, wherein the gap between the stator and the rotor gradually decreases in the direction of motion of the processed slurry. Sludge mixed with fuel oil at a temperature of 60 ÷ 80 ° C by gravity to a larger area of the gap. As the rotor rotates at high speed, centrifugal force throw the liquid from the rotor, the fluid is exposed to high shear stresses, which grinds solids in combination with centrifugal force. Furthermore, the combination of protrusions and recesses when the rotor causes the hammer impact and shearing falling particles.By adjusting the gap between the stator and the rotor is possible to achieve a desired particle size. Intensive treatment processes allow for the size of solid particles 2 ÷ 6 microns. The resulting mixture is fed to the input of the HCA, there is also supplied fuel from the tank of fuel oil. The resulting homogenized mixture of crushed mud and oil, about 1:20, arrives at an intermediate container of 3 ÷ 4 m3 that is part of the installation where the pump is supplied by burning or storage capacity.

In the latter case, after the full processing of the sludge fuel oil from the storage tank pump recycled three times through the HCA by the pump.

The approximate parameters of the processed sludge: humidity 30 ÷ 40% organic content 50 ÷ 60%, ash content of 2%.

Achievable results

As a result of this processing slurry and mixing the product with fuel oil, 3% moisture and ash content of 0.2 in the above ratio forms the new fuel with a moisture content – 4.7% and 0.21% ash (permisible ash should not exceed 0.3 %).

Achievable results:

  • Full utilization of sludge
  • Increase the total storage capacity by 5-10%
  • Fuel savings in the amount of 4-8% of the storage volume
  • No dumping of sludge