CN-121990748-A - Filter pressing treatment process for oily sludge

CN121990748ACN 121990748 ACN121990748 ACN 121990748ACN-121990748-A

Abstract

The invention discloses a filter pressing treatment process for oily sludge, and belongs to the technical field of oil and gas field waste treatment. The method comprises the steps of firstly feeding oily sludge into a preheating tempering tank, adding alkyl glycoside and amorphous silica powder, then carrying out gradient heating and stirring to obtain pretreated sludge, then feeding the pretreated sludge into a mixing reactor, adding a composite modified filter aid prepared from hydrophobicized modified diatomite, quaternized modified chitosan, amino modified graphene oxide and the like, carrying out stirring-ultrasonic treatment to obtain demulsified sludge, feeding the demulsified sludge into a filter press which is pre-coated with a porous non-hydrophobicized diatomite precoat and is provided with a double-layer breathable gradient pore-size filter cloth, and finally carrying out low-pressure cloth and gradient pressure-increasing filter pressing, feeding instant high-pressure nitrogen gas after filter pressing to slightly blow out cakes, and blowing the filter cloth to complete the operation. The technology can effectively break the oil-water-silicon fine particle emulsifying system, relieve the problem of high altitude low temperature agglomeration and microphase separation of the system, realize graded interception and anti-blocking, and improve the filter pressing efficiency and stability.

Inventors

DENG MING
JIANG WENJING
YANG JIE
LI ZAIYUN
DING WANG
LIU JINLING
LI ZHONGMING
WANG JUN

Assignees

成都钠镁化学有限公司

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (10)

1. The filter pressing treatment process for the oily sludge is characterized by comprising the following steps of: S1, sludge preheating treatment, namely feeding oil-containing sludge of an oil-gas field into a preheating tempering tank, adding surface modifier alkyl glycoside and amorphous silicon powder, and then carrying out gradient heating and stirring treatment to obtain pretreated sludge after stirring; s2, adding a filter aid and demulsifying, namely feeding the pretreated sludge into a mixing reactor, adding a composite modified filter aid, and then stirring and carrying out ultrasonic treatment to obtain demulsifying sludge; The composite modified filter aid is prepared by mixing hydrophobically modified diatomite, quaternized modified chitosan, amino modified graphene oxide, trisodium citrate, sodium dodecyl benzene sulfonate and polyoxyethylene sorbitan monooleate; S3, gradient filter pressing, namely feeding demulsified sludge into a filter press, firstly distributing the demulsified sludge at the pressure of less than or equal to 0.5bar, and then carrying out gradient boosting to the set pressure for continuous filter pressing; s4, cake discharging and filter cloth cleaning, namely after the filter pressing is finished, introducing instant high-pressure nitrogen into a filter chamber of the filter press, slightly back-blowing to finish cake discharging, and blowing the filter cloth to finish single filter pressing operation.
2. The filter pressing treatment process of the oily sludge according to claim 1, wherein in the step S1, the initial temperature of the oily sludge is-15 ℃ to 10 ℃, the temperature is gradually increased to 15 to 20 ℃ at a rate of 1 to 2 ℃ per minute, the alkyl glycoside accounts for 0.1 to 0.3 percent of the mass of the sludge, the amorphous silicon powder accounts for 0.3 to 1.2 percent of the mass of the silicon fine particles, the particle size is 1 to 2 mu m, and the standing time is 5 to 10 minutes.
3. The oil-containing sludge filter pressing treatment process according to claim 1, wherein in the step S2, the preparation process of the quaternized modified chitosan is sequentially that quaternary ammonium salt groups are grafted on chitosan firstly, citric acid accounting for 0.1% -0.2% of the mass of the chitosan is added after grafting is completed, demulsification stability of the quaternized chitosan in a low-temperature environment is improved, and then the quaternized modified chitosan is finally obtained through low-temperature activation by microwaves at 55-65 ℃.
4. The oil-containing sludge filter pressing treatment process according to claim 1, wherein in the step S2, the amination modified graphene oxide is obtained by intercalation of graphene oxide through ethylenediamine.
5. The oil-containing sludge press filtration treatment process according to claim 1, wherein in the step S2, the hydrophobically modified diatomaceous earth is obtained by grafting diatomaceous earth with methyltrimethoxysilane.
6. The oil-containing sludge filter pressing treatment process according to claim 1, wherein the composite modified filter aid comprises the following components in parts by weight: 40-50 parts of hydrophobized modified diatomite, 25-35 parts of quaternized modified chitosan, 5-10 parts of amination modified graphene oxide, 5-10 parts of trisodium citrate, 3-5 parts of sodium dodecyl benzene sulfonate and 0.5-1 part of polyoxyethylene sorbitan monooleate; The addition amount of the composite modified filter aid is 0.3-0.45% of the total mass of the dry basis of the oil-containing sludge.
7. The filter pressing treatment process of the oily sludge according to claim 1, wherein in the step S2, the temperature of the mixing reaction is 15-20 ℃, the reaction time is 10-15 min, and the temperature of the ultrasonic treatment is less than or equal to 25 ℃.
8. The filter pressing treatment process of the oily sludge according to claim 1, wherein in the step S3, the breathable gradient pore-size filter cloth has a double-layer structure, the pore diameter of an outer layer in contact with the sludge is 10-15 μm, the pore diameter of an inner layer in contact with a filter plate is 5-8 μm, and the thickness of the non-hydrophobized diatomite precoat is 0.2-0.3 mm.
9. The oil-containing sludge filter pressing treatment process according to claim 1, wherein in the step S3, the pressure of the low-pressure cloth is 0.3-0.5 bar, the duration is 5-8 min, the gradient boosting rate is 0.5-1 bar/min, the final pressure is 20-25 bar, the duration is 20-30 min, the initial pressure of the dry nitrogen is 0.8-1.0 bar, the temperature after temperature and humidity regulation is 20-25 ℃, and the relative humidity is 15% -20%.
10. The oil-containing sludge filter pressing treatment process according to claim 1, wherein in the step S4, the pressure of the instantaneous high-pressure nitrogen is 5-8 atm, and the micro back flushing time is 0.5-1 min.

Description

Filter pressing treatment process for oily sludge Technical Field The invention belongs to the technical field of oil and gas field waste treatment, and particularly relates to an oil-containing sludge filter pressing treatment process. Background In the exploitation process of oil and gas fields, the sludge generated by exploitation can naturally wrap siliceous particles in stratum, and meanwhile, chemical additives such as demulsifier, corrosion inhibitor and the like added for ensuring the exploitation work to be smoothly carried out can interact with siliceous particles, crude oil and water to finally form oily sludge. The oily sludge belongs to dangerous waste, and if the oily sludge is not properly disposed in time, crude oil is easy to leak, so that soil and underground water sources are polluted, and the surrounding ecological environment is destroyed. Therefore, the filter pressing process is one of important operations for realizing solid-liquid separation of the oil-containing sludge and ensuring the subsequent treatment to reach the standard, and is widely applied to the field of oil-containing sludge treatment. The conventional filter pressing process mostly adopts the processes of normal temperature and normal pressure feeding, adding conventional filter aid (such as polyaluminium chloride and polyacrylamide) and high-pressure compacting and filtering, is widely applied to the treatment of oily sludge of common oil and gas fields at present, and is suitable for the conventional working conditions of normal temperature, normal pressure and low silicon fine particle content. However, in the high-altitude oil-gas field area (such as Qinghai oil field, north-astringing gas field, tibetan north-lunar-drawing basin oil-gas field, etc.) with the altitude of more than or equal to 3000 m, due to the special stratum structure and strong weathering effect of the plateau siliceous stratum at the area, sludge generated by exploitation is different from that of the common oil-gas field to some extent, so that the filter pressing process which is originally applicable to the conventional scene is originally caused, and a plurality of technical defects are exposed in the practical application of the high-altitude oil-gas field, and the method comprises the following steps: The environment temperature of the high-altitude area is kept at-15 ℃ to 10 ℃ throughout the year, oily sludge is easy to freeze or high-viscosity semi-solid in a low-temperature environment, so that a feed inlet is blocked during feeding, meanwhile, the low-temperature environment can reduce the fluidity of the sludge, so that the sludge on the surface of the filter cloth is unevenly distributed, the situation of partial dry block accumulation and partial filter cloth idling occurs, the filter pressing efficiency is reduced, in addition, the toughness of the filter cloth is reduced at the low temperature, the filter cloth is easy to break in the high-pressure filter pressing process (the compression pressure is more than or equal to 20 bar), the demulsification and flocculation activity of the conventional filter aid are reduced, and the action effect is weakened. Secondly, special silicon fine particles (derived from the special structure and strong weathering effect of the high altitude area plateau siliceous stratum, the mass fraction of SiO 2 is more than or equal to 25 percent, wherein the particle with the particle diameter less than or equal to 5 mu m accounts for more than or equal to 60 percent) in the high altitude oily sludge interact with chemical additives such as demulsifiers, corrosion inhibitors and the like, crude oil and moisture added in the exploitation process to form an oil-water-siliceous fine particle stable emulsifying system, so that the filter pressing difficulty is further increased, the conventional filter aid is easy to carry out adsorption reaction with the silicon fine particles, the stable system is difficult to effectively break emulsion and flocculate, and the viscous substance formed by the reaction of the conventional filter aid and the silicon fine particles can block the filter cloth and the filter pressing equipment flow passage, so that the equipment needs to be frequently stopped and cleaned, and the operation and maintenance cost is increased. And in addition, the cooperative interference of silicon fine particles and chemical additives further aggravates the problem of filter cloth blockage, namely the conventional filter cloth pores are usually more than or equal to 10 mu m, and the silicon fine particles easily penetrate the filter cloth pores or rapidly form a compact siliceous filter cake layer on the surface of the filter cloth, so that the permeability of the filter cloth is reduced, the pressure of filter pressing is increased, the filtering speed is reduced, even the phenomenon of 'filter pressing stagnation' occurs, and the treatment progress of oily sludge is influenced. Based on the me