CN108203218B

CN108203218B - Harmless treatment process for oily sludge

Info

Publication number: CN108203218B
Application number: CN201810012618.8A
Authority: CN
Inventors: 李林瑛
Original assignee: Jin Tan Environment Technology Tianjin Co ltd
Current assignee: Jin Tan Environment Technology Tianjin Co ltd
Priority date: 2018-01-05
Filing date: 2018-01-05
Publication date: 2020-09-01
Anticipated expiration: 2038-01-05
Also published as: CN108203218A

Abstract

The invention relates to a harmless treatment process of oily sludge, which comprises the following steps: a first mixing step, namely uniformly stirring the oily sludge and the foamed polymer powder to obtain a first polymer sludge mixture; a squeezing separation step, namely placing the first polymer sludge mixture into a squeezer, squeezing out liquid in the first polymer sludge mixture to obtain an oil-water mixture and a squeezed mixture, and separating oil and water after the oil-water mixture stands; and a three-phase separation step, namely placing the sludge mixture in a container, adding water, and layering, wherein the upper layer is a polymer powder oil stain layer, the middle layer is a water layer, and the lower layer is a sludge layer.

Description

Harmless treatment process for oily sludge

Technical Field

The invention relates to a harmless treatment process of oily sludge.

Background

The refining enterprises generate a large amount of oily sludge in the petroleum refining and wastewater treatment processes, and the oily sludge mainly comes from an oil separation tank, a flotation tank, residual activated sludge, a crude oil dehydration tank, an oil storage tank, a sump oil tank and the like. The components of the sludge are complex, the sludge belongs to a stable multiphase system, the mixture is sufficient, the viscosity is high, the solid phase is difficult to completely settle, and the oily sludge is difficult to treat. At present, in the petrochemical industry of China, about 80 ten thousand tons of oily sludge are generated each year on average. Along with the continuous expansion of the scale of the production devices of enterprises, the corresponding total amount and types of waste residue discharge are gradually increased, so that the total amount of pollution discharge and pollution treatment cost of the enterprises also show a rising trend. In recent years, with the increasing requirements of the national environmental protection regulation standard, the environmental protection law enforcement is increased, and the pollution control and resource utilization of the solid waste generated in the production process become difficult problems in the petroleum and petroleum processing industry. The newly revised 'environmental protection and control law of solid waste pollution' puts forward more strict requirements on the prevention and control of the solid waste. The treatment and utilization of solid wastes have been listed as important work contents for building an economical society.

With the development of national economy and the attention on environmental protection, more and more institutions develop the research on the treatment of oily sludge. However, most of the technologies have difficulty in popularization and application to form industrial production due to high treatment cost, long process flow, complex operation, non-ideal treatment effect or other reasons in many aspects. At present, most of oily sludge is treated in an open air stacking or landfill mode, the sludge generally contains hydrocarbons, benzene series, phenols, anthracenes and other substances, and is accompanied by malodor and toxicity, if the sludge is directly contacted with the natural environment, soil, water and vegetation are greatly polluted, and petroleum resources are wasted.

CN1488591A proposes a method for treating oily sludge, which comprises mechanically dewatering oily sludge, mixing with extractant, preheating, homogenizing, thermally extracting, dewatering, separating solid and liquid, introducing the liquid phase into a coking device, and using the solid phase as fuel. The technology needs to preheat materials in the extraction process, the preheating temperature is 50-100 ℃, the operation temperature in the extraction process is 100-150 ℃, and the energy consumption is large; the oily sludge contains too much water, the extraction is not thorough, and the residue after extraction is dried and then needs to be burnt to achieve the harmless effect.

CN1526797A proposes an extraction method of oily sludge, which selects light coal tar (boiling point of 45-90 ℃ at normal pressure) as an extracting agent, petroleum ether, light oil or C5, and separates water, oil and sludge in the oily sludge by utilizing the dissolving effect of a solvent on fuel oil in the oily sludge. However, the extraction process conditions of the technology are that the extraction temperature is 45-55 ℃, the energy consumption in the extraction process is high, the oily sludge is not deeply dehydrated before extraction, and the oil extraction of the oily sludge is not easy to be thorough after extraction.

CN1765781A proposes a method for treating oily sludge, which adopts the mixing of an extracting agent and the oily sludge, the extraction, evaporation, dehydration treatment and solid-liquid separation, and is characterized in that the method is a multi-effect multi-stage or single-effect multi-stage extraction and evaporation system, and the operating conditions of the multi-effect multi-stage extraction and evaporation system are as follows: the first stage of the method adopts normal pressure, the temperature is 95-115 ℃, the pressure of the last stage is 0.01-0.60 MPa, and the temperature is 125-175 ℃. The technology does not carry out deep dehydration treatment on the oily sludge before extraction, the moisture in the oily sludge is too much in the process, the extraction is not thorough, the content of organic matters in the separated solid phase is high, the materials need to be heated in the extraction process, multi-stage extraction is needed, the process flow is long, the number of equipment is large, the equipment investment is large, and the energy consumption is large.

CN101633574A and CN101362979A propose a method for treating oil-containing sludge, in which the oil-containing sludge is subjected to quenching and pressing filtration, and then mixed with coal to be used as fuel, and the oil in the oil-containing sludge cannot be recycled.

CN101343137A proposes a method for treating oil-containing sludge, which comprises subjecting oil-containing sludge to thermal refining, dewatering, drying, etc., and then incinerating. The oil-containing sludge drying process has high energy consumption, and is easy to generate foul tail gas and generate new pollution.

CN103693833A proposes a method for treating oily sludge, comprising the following steps: firstly, mechanically dehydrating the oily sludge to reduce the water content of the oily sludge to 50-90%, then mixing the mechanically dehydrated oily sludge and sand grains with the grain diameter of 20-200 mu m according to the mass ratio of 1: 0.05-0.3, uniformly stirring, then sending the mixture into a squeezing device for squeezing, mixing a mud cake generated after squeezing with an extracting agent, uniformly stirring for extraction, sending the mixed material into a solid-liquid separator after extraction is finished, directly refining separated liquid, and drying separated solid residues to be treated as solid wastes.

In the prior art, because the oily sludge contains a large amount of water, a dehydration step is required, so that a better treatment effect is obtained, but a large amount of energy is consumed in the dehydration process. The treatment process in the prior art is complex and can not realize the harmless treatment of the oily sludge.

Disclosure of Invention

In order to solve the technical problems, the invention provides a harmless treatment process of oily sludge, which comprises the following steps:

a first mixing step, namely uniformly stirring the oily sludge and the foamed polymer powder to obtain a first polymer sludge mixture;

a squeezing separation step, namely placing the first polymer sludge mixture into a squeezer, squeezing out liquid in the first polymer sludge mixture, and separating out oil-water mixed liquid to obtain a squeezed mixture;

and a three-phase separation step, namely placing the obtained mixture in a container, adding water, and layering, wherein the upper layer is a polymer powder oil stain layer, the middle layer is a water layer, and the lower layer is a mud layer.

The water content of the oily sludge is 10-90%.

The stirring time in the first mixing step is 10 to 40 minutes.

In the first mixing step, the mass ratio of the oily sludge to the foamed polymer powder is 1: 0.2-2.

The innocent treatment process also comprises a second mixing step, wherein the second mixing step comprises the following steps: and adding the foaming polymer powder into the pressed mixture again, and uniformly mixing to obtain a second polymer sludge mixture.

In the second mixing step, the mass ratio of the pressed mixture to the foamed polymer powder is 1: 0.1-1.

In the three-phase separation step, the mass ratio of the second polymer sludge mixture to water is 1: 0.1-2.

The standing time in the three-phase separation step is 10-60 minutes.

The foaming polymer powder is selected from one or more of foaming polyethylene powder, foaming polypropylene powder, foaming styrene powder, foaming ABS powder, foaming polyurethane powder, foaming polyacrylic acid powder and foaming rubber powder.

The particle size of the foamed polymer powder is 1-100 microns.

The innocent treatment process also comprises an adsorption step, wherein the adsorption step is used for treating the water layer obtained in the three-phase separation step.

The innocent treatment process also comprises a separation step, wherein the separation step is used for spin-drying and separating the polymer powder and the oil stain in the polymer powder oil stain layer obtained in the three-phase separation step at a high speed.

Separation is difficult because the oil, water and silt in the oil-containing sludge are well mixed and form a uniform liquid. According to the invention, the foamed polymer powder and the oily sludge are fully mixed, then squeezed and mixed with the foamed polymer powder again, and the adsorption capacity of the foamed polymer powder is utilized to realize the efficient separation of oil and water sludge. The COD of the separated water is less than 30mg/L after the water is filtered by the adsorption powder. The mass content of organic matters in the separated mud is lower than 1 percent. The foaming polymer powder can be efficiently separated from oil stain, and can be recycled through simple spin-drying separation.

The above-described and other features, aspects, and advantages of the present application will become more apparent with reference to the following detailed description.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The invention provides a harmless treatment process of oily sludge, which comprises the following steps:

In a preferred embodiment of the present invention, the water content of the oily sludge is 10 to 90%.

As a preferred embodiment of the present invention, the stirring time in the first mixing step is 10 to 40 minutes.

In a preferred embodiment of the present invention, in the first mixing step, the mass ratio of the oily sludge to the foamed polymer powder is 1: 0.2-2.

In a preferred embodiment of the present invention, in the second mixing step, the mass ratio of the pressed mixture to the foamed polymer powder is 1: 0.1-1.

In a preferred embodiment of the present invention, the harmless treatment process further comprises a second mixing step, wherein the second mixing step comprises adding the foamed polymer powder again to the pressed mixture, and uniformly mixing to obtain a second polymer sludge mixture.

As a preferred embodiment of the present invention, in the three-phase separation step, the mass ratio of the second polymer sludge mixture to water is 1: 0.1-2.

As a preferred embodiment of the present invention, the standing time in the three-phase separation step is 10 to 60 minutes.

In a preferred embodiment of the present invention, the foamed polymer powder is one or more selected from the group consisting of foamed polyethylene powder, foamed polypropylene powder, foamed styrene powder, foamed ABS powder, foamed polyurethane powder, foamed polyacrylic acid powder, and foamed rubber powder.

In a preferred embodiment of the present invention, the particle size of the foamed polymer powder is 1 to 100. mu.m.

In a preferred embodiment of the present invention, the foamed polymer powder further comprises a demulsifier, and the demulsifier accounts for 0.1-5% by mass of the foamed polymer powder.

As a preferred embodiment of the present invention, the innocent treatment process further comprises an adsorption step for treating the aqueous layer obtained in the three-phase separation step.

As a preferred embodiment of the present invention, the innocent treatment process further comprises a separation step for spin-drying the polymer powder and the oil stain in the polymer powder oil stain layer obtained in the three-phase separation step at a high speed.

Hereinafter, the present invention will be described in more detail by way of examples, but it should be understood that these examples are merely illustrative and not restrictive. The starting materials used are all commercially available, unless otherwise stated.

The present invention is described in detail below with reference to several examples.

Example 1

300g of oil sludge (with the water content of 69.4%, the oil content of 27.2% and the solid content of 3.4%) is added with 130g of foamed polyethylene powder and stirred uniformly (for 10 min), the mixture is placed in a squeezer, oil and water are squeezed out, and then the rest is placed in a special separator for three-phase separation of oil, mud and water. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. Standing the recovered oil water for 30min to separate the oil water, wherein 76.45g of the recovered oil product and 1.94 percent of the organic matter mass content of the sludge are obtained.

Example 2

300g of oil sludge (water content 69.4%, oil content 27.2% and solid content 3.4%) is added into 130g of foamed polyethylene powder and stirred uniformly (10 min), and the mixture is placed in a squeezer to squeeze oil and water out. Then the rest part is put into a special separator for oil, mud and water separation. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. Standing the recovered oil water for 30min to separate the oil water, wherein 73.23g of the recovered oil product is obtained, and the mass content of the organic matter in the sludge is 2.11%.

Example 3

Adding 300g of oil sludge (with water content of 9.3%, oil content of 87.7% and solid content of 3%) into 130g of foamed polyethylene powder, stirring uniformly (for 10 min), placing in a squeezer, and squeezing out oil water; then the rest part is put into a special separator for oil, mud and water separation. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. Standing the recovered oil water for 30min to separate the oil water, wherein 221.66g of the recovered oil product is obtained, and the mass content of the organic matter in the sludge is 2.81%.

Example 4

Taking 300g of oil sludge (with the water content of 69.4%, the oil content of 27.2% and the solid content of 3.4%), adding 130g of foamed polyethylene powder, uniformly stirring (10 min), placing in a squeezer, squeezing out oil water, secondarily adding powder to the squeezed and deoiled sludge, adding 30g of foamed polyethylene powder, stirring (10 min), uniformly stirring, standing for 15min, and then placing in a special separator for three-item separation of oil, sludge and water. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. Standing the recovered oil water for 30min to separate the oil water, wherein 80.83g of the recovered oil product is obtained, and the mass content of the organic matter in the sludge is 1.13%.

Example 5

Adding 300g of oil sludge (water content 69.4%, oil content 27.2%, solid content 3.4%) into 130g of foamed polyethylene powder, stirring uniformly (10 min), placing in a squeezer, and squeezing out oil water; standing the recovered oil water (30 min) to separate the oil water from the water. And (3) squeezing the deoiled sludge, adding powder for the second time, adding 30g of foamed polyethylene powder, stirring (10 min), standing for 15min after uniform stirring, and then putting the mixture into a special separator for oil, mud and water separation. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. And standing the recovered oil water for 30min to separate the oil from the water, wherein 78.11g of the recovered oil product contains 1.45% of the organic matter in the sludge.

Example 6

Adding 300g of oil sludge (with water content of 9.3%, oil content of 87.7% and solid content of 3%) into 130g of foamed polyethylene powder, stirring uniformly (for 10 min), placing in a squeezer, and squeezing out oil water; standing the recovered oil water (30 min) to separate the oil water from the water. And (3) squeezing the deoiled sludge, adding powder for the second time, adding 30g of foamed polyethylene powder, stirring (10 min), standing for 15min after uniform stirring, and then putting the mixture into a special separator for oil, mud and water separation. The separated powder can be reused after centrifugal drying, the water phase can be filtered by modified adsorption powder (COD is less than 30 mg/L), and the sludge is harmless. Standing the recovered oil water for 30min to separate the oil water, wherein 241.20g of the recovered oil product is obtained, and the mass content of the organic matter in the sludge is 1.45%.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. All equivalent changes and modifications made according to the disclosure of the present invention are covered by the scope of the claims of the present invention.

Claims

1. A harmless treatment process of oily sludge is characterized by comprising the following steps:

and a three-phase separation step, namely placing the mixture obtained in the squeezing separation step into a container, adding water, and layering, wherein the upper layer is a polymer powder oil stain layer, the middle layer is a water layer, and the lower layer is a mud layer.

2. The process according to claim 1, wherein the water content of the oily sludge is 10-90%.

3. The process according to claim 2, wherein the stirring time in the first mixing step is 10 to 40 minutes.

4. The process according to claim 3, wherein in the first mixing step, the mass ratio of the oily sludge to the foamed polymer powder is 1: 0.2-2.

5. The innocent treatment process of oily sludge according to claim 4, characterized in that the innocent treatment process further comprises a second mixing step, and the second mixing step comprises the following steps: and adding the foaming polymer powder into the pressed mixture again, and uniformly mixing to obtain a second polymer sludge mixture.

6. The process according to claim 5, wherein in the second mixing step, the mass ratio of the pressed mixture to the foamed polymer powder is 1: 0.1-1.

7. The process according to claim 6, wherein in the three-phase separation step, the mass ratio of the second polymer sludge mixture to water is 1: 0.1-2.

8. The process according to claim 7, wherein the standing time in the three-phase separation step is 10 to 60 minutes.

9. The process according to claim 8, wherein the process further comprises an adsorption step for treating the aqueous layer obtained in the three-phase separation step.

10. The process of claim 9, wherein the process further comprises a separation step for spin-drying the polymer powder and the oily dirt in the polymer powder oily dirt layer obtained in the three-phase separation step at a high speed.