What problems will be encountered during the use of walnut shell filter in the oil field

In the treatment of oily wastewater in oil fields, quartz sand, walnut shells, microporous ceramics, membranes and fiber media are used as filter materials. Among them, walnut shell has a wide range of sources, strong adsorption and interception capacity. Among them, walnut shell has a wide range of sources, strong adsorption and interception capacity, strong hydrophilicity and resistance to oil leaching, high hardness, good wear resistance, stable chemical properties, and Low particle density, easy to carry out hydraulic backwash, and the required backwash intensity is low, and the characteristics of relatively high reusability, so now most oil fields use walnut shells as filter materials.
     Walnut shell as a filter material has the ability to intercept the pollution of ordinary filter media, and can directly intercept suspended particles in wastewater. On the other hand, it can rely on its unique surface physical and chemical properties to emulsify oil in oil production wastewater through adhesion. The particles are adsorbed on the surface of the filter material or the agglomerates on the surface of the filter material to be removed.
     Walnut shells can be used as an adsorbent, which has been proven by many sciences. However, the viscosity and surface tension of the oil negatively affect the adsorption rate of walnut shells. At the same time, the re-recovery of oil from walnut shells has a higher recovery rate than other water media, which can be achieved only through force compression. At the same time, walnut shell filter material is suitable for filtering well washing wastewater after pretreatment. In a certain filtration cycle, as the particle size of the filter material increases, the removal rate of oil and turbidity shows a downward trend, but the filter material with a smaller particle size is more likely to be saturated and penetrated; at the same time, when backwashing Hot water is used as the backwashing water. The backwashing strength is less than that of ordinary quartz sand filter media. The strength and washing time depend on the particle size of the filter material. The filter material with larger particle size is easier to backwash.