CN109970146A - An oil-water separator for treating oily wastewater and its application in the treatment of crude oil electric desalination wastewater - Google Patents

Abstract

The oil-water separating agent that the present invention provides a kind of processing oily waste water includes two 100 parts of tertiary butyl ether of ethylene glycol, 30-80 parts of the polyisobutene of average molecular weight 800-1300,20-60 parts of propylene glycol diacetate, 5-20 parts of alpha-pyrrolidone in terms of mass fraction；Suitable for handle oil-in-water type containing mineral oil, bio-oil waste water.It is particularly suitable for crude oil such as peracid crude oil with poor quality, weight crude oil with poor quality adds the processing of oily waste water that electric desalting apparatus is arranged under the conditions of more demulsifier, oil content in separating obtained water phase can control 150mg/L or less, the water content of gained oil phase can be lower than 0.3m%, and crude oil goes atmospheric and vacuum distillation unit normal process after being pumped into electro-desalting.

Description

An oil-water separating agent for treating oily wastewater and its treatment in crude oil electric desalination drainage applications in

technical field

The invention belongs to the field of wastewater treatment, in particular to an oil-water separation agent for treating oily wastewater and its application in the treatment of crude oil electric desalination drainage.

Background technique

Deep electrical desalination is the basic method to treat the salt contained in crude oil. Under the condition of high voltage electric field and heating, supplemented by demulsifier, ultrasonic wave and other means, the salt contained in crude oil is removed by one or more injections of water such as 2-5%. Parts are washed into water, and then oil-water separation is carried out, while controlling the water content of the treated crude oil and the oil content of the drainage. Through the deep electric desalination process, the crude oil can generally be treated to the extent that the salt content is lower than 3 mg/L and the water content is lower than 0.2%, and the oil content of the discharged wastewater can be controlled within 150 mg/L. When the operation is normal, the oil content of the wastewater discharged by electric desalination is low, and it can be sent to the sewage treatment device for normal oil separation-flotation-biochemical process treatment.

However, due to the fluctuation and complexity of crude oil conditions, and the limitation and lag of electric desalination control and adjustment methods, the electric desalination devices of many refineries often discharge a large amount of wastewater with oil content far exceeding 150 mg/L, and sometimes the oil content of the drainage can even reach 10. % or so, mixing this high oily wastewater into the electric desalination injection water and returning it to the electric desalination treatment usually has limited effect, or it will cause the problem that the salt and water content of the crude oil after electric desalination does not meet the standard. This kind of electrical desalination wastewater with high oil content will have a great impact on the oil separation-flotation-biochemical process when it is sent to the sewage plant for treatment, or it will be difficult to handle, and often causes the wastewater to block the reservoir. On the other hand, the waste oil recovered from the electrical desalination wastewater with high oil content is usually inconvenient to be used directly as raw materials for atmospheric and vacuum, catalytic cracking or coking due to the enrichment of complex components in other wastewaters. Some are also difficult to transport.

Therefore, it is necessary to develop a technology for treating such high oily wastewater, especially a method for realizing high-efficiency oil-water separation by simply mixing an oil-water separating agent.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides an oil-water separation agent for treating oily wastewater and its application in the treatment of crude oil electric desalination wastewater.

The oil-water separating agent for treating oily wastewater in the present invention comprises, in parts by mass, 100 parts of ethylene glycol di-tert-butyl ether, 30-80 parts of polyisobutylene with an average molecular weight of 800-1300, 20-60 parts of propylene glycol diacetate, α -5-20 parts of pyrrolidone.

Wherein, the polyisobutylene is polyisobutylene with an average molecular weight of 800 and/or polyisobutylene with an average molecular weight of 1300. Preferably, the two are used in combination, and the ratio of the two by mass is preferably 100: (30-60); the Propylene glycol diacetate is 1,2-propylene glycol diacetate.

Among them, the preferred proportions are 100 parts of ethylene glycol di-tert-butyl ether, 40 parts of polyisobutylene with an average molecular weight of 800, 20 parts of polyisobutylene with an average molecular weight of 1300, 40 parts of propylene glycol diacetate, and 10 parts of α-pyrrolidone.

The oil-water separating agent of the present invention can be prepared by mixing ethylene glycol di-tert-butyl ether, polyisobutylene, propylene glycol diacetate and α-pyrrolidone in a container and stirring evenly, and can be slightly heated. The obtained oil-water separating agent is a stable emulsion.

The oil-water separator of the present invention is suitable for treating oil-in-water type oily wastewater, the oil includes mineral oil and biological oil, wherein the mineral oil includes crude oil and engine oil, and the biological oil includes vegetable oil and animal oil; It is easy to disperse, dissolve and diffuse, has strong demulsification and fusion ability to the oil or grease, and easily forms a continuous oil phase after treatment. For oily wastewater with oil content less than 20%, 50-2000mg of oily wastewater can be added to 1L of oily wastewater, or 0.5-5m% of oil content, operating under the condition of water temperature 20-150℃, can obtain higher oil content. Oil-water separation effect; the oil content in the treated water obtained by separating the oil phase can be controlled to below 150mg/L or even below 100mg/L, and the water content of the recovered oil can be lower than 0.3m% or even lower than 0.2m%. The water phase obtained by separating the oil phase can reach a clear and transparent level. For low-temperature oil-containing wastewater, where the oil or grease is in a solidified state or high viscosity, the oil-water separating agent of the present invention can be added first to separate the wastewater into an aqueous phase and an oil-rich phase, and the oil-rich phase is heated to the molten state of the oil or grease or The low viscosity level is further separated from oil and water, and the oil content in the water phase obtained by the final separation can be controlled to below 150mg/L or even below 100mg/L, and the water content of the obtained oil phase can be lower than 0.3m% or even lower than 0.2m%.

The oil-water separating agent of the present invention is also a high-efficiency anti-demulsifier, and is especially suitable for the treatment of crude oil such as high-acid and inferior crude oil, heavy and inferior crude oil with more demulsifiers added to the treatment of oily wastewater discharged from an electric desalination device, and can electrically desalt crude oil. The oily wastewater is well separated, the oil content in the separated water phase can be controlled to below 150mg/L or even below 100mg/L, the water content of the obtained oil phase can be lower than 0.3m% or even lower than 0.2m%, the salt content Below 3mg/L. Emulsifying components and/or demulsifier components contained on the surface of oil droplets in the oil-containing wastewater discharged from the electrical desalination device often make the oil droplets stable in water and difficult to collide and fuse. The high-acid and inferior crude oil contains a lot of naphthenates, which makes it difficult to break demulsification and desalinate. Separation of oil and water by sedimentation and centrifugation.

The oil-water separation agent of the invention is used for the treatment of the waste water containing oil exceeding the standard discharged from the electric desalination of crude oil, and can directly use the waste water temperature conditions such as 130-145° C. and use the waste water buffer storage tank as the oil-water separation tank, and basically does not increase other needs more investment. The equipment or container can also play an auxiliary and guarantee role in the operation of the crude oil electric desalination unit. Preferably, two or more oil-water separation tanks are used to separate the oil phase and the water phase by gravity settling. For the accumulated low-temperature crude oil-containing wastewater, the oil-water separating agent of the present invention can be added first, and the wastewater is divided into an aqueous phase and an oil-rich phase, and the oil-rich phase is heated to 80-150 ° C for oil-water separation, and finally the oil-containing water in the obtained water phase is separated. The amount of oil can be controlled to below 150mg/L or even below 100mg/L, the water content of the obtained oil phase can be lower than 0.3m% or even lower than 0.2m%, and the salt content is lower than 3mg/L.

The oil-water separating agent of the present invention can be mixed with the wastewater by a pipeline mixer, namely a static mixer, or mechanical stirring after being injected into the wastewater, and then gravity sedimentation and stratification or centrifugation can be used for oil-water separation, wherein the components of the separating agent are basically It enters the oil phase and is further utilized with the recovered oil, and does not substantially affect the further processing of the recovered oil. For example, the oil phase recovered from the treatment of crude oil electrical desalination wastewater can be pumped into the crude oil after electrical desalination to go to atmospheric and vacuum units for normal processing, and can also be sent to catalytic cracking units or coking units for processing when the quality is poor. The oil-water separating agent of the present invention contains no inorganic matter and no ash, usually only accounts for 0.5-5% of the recovered crude oil, and does not affect the operation and effect of atmospheric and vacuum units, catalytic cracking units or coking units.

Detailed ways

The present invention will be specifically described below through examples and comparative examples, but it does not constitute a limitation to the present invention.

Embodiment 1-10, comparative example 1-9

According to the proportions in Table 1, the oil-water separating agents of Examples 1-10 and Comparative Examples 1-9 were prepared respectively; the compounding method was to first add the ethylene glycol di-tert-butyl ether and propylene glycol diacetate of the ingredients in a 500ml beaker. , α-pyrrolidone, add polyisobutylene with an average molecular weight of 800 in the electric stirring, add polyisobutylene with an average molecular weight of 1300 after stirring, continue to stir until uniform, and then put them into reagent bottles for storage.

Table 1 Proportion of oil-water separator, unit g

Application example 1

Take the oily wastewater discharged from a high-acid and inferior crude oil electric desalination device, the oil content is 8.1g/L, and it will not stratify at room temperature or 90℃ for 5 hours, and will not form a continuous oil phase; add 1000ml of the oily wastewater into a 1000ml beaker, heat it to 80°C and add 230 μl of the oil-water separator of Example 1, about 200mg (according to 2.5m% of the oil content), stir well, place it in an 80°C incubator for 2 hours, and record the oil-water separation at 1 hour and 2 hours. Detect the oil content of the water phase after standing for 2 hours.

According to the same method, 1000ml of the oily waste water was added to 18 1000ml beakers in turn, heated to 80°C, and 230μl of the oil-water separation agent of Example 2-10 and Comparative Example 1-9 were added in turn, about 200mg (according to 2.5% of the oil content). Add m%, only one oil-water separator is added to each beaker), stir evenly, place it in an 80°C incubator for 2h, record the oil-water separation at 1h and 2h, and detect the oil content of the water phase after 2h . In addition, 1000ml of the oily wastewater was added to a 1000ml beaker, heated to 80°C and directly placed in an 80°C incubator for 2 hours as a blank control.

The test conditions are listed in Table 2, where the oil content of the water phase is the oil content of the water sample taken from the depth of 20-30% of the liquid at the bottom of the cup.

Take 5ml of the continuous oil phase collected from the waste water treated by the oil-water separator in Examples 1-10, mix well, measure the water content to be 0.18m%, and measure the salt content to be lower than 3mg/L.

Table 2 The treatment effect of each oil-water separator on 8.1g/L crude oil electric desalination wastewater at 80℃, the addition amount is 200mg/L

.

Application example 2

Take the oily waste water discharged from a high-acid and inferior crude oil electric desalination unit, with an oil content of 46g/L, which is kept in a closed place at room temperature or 90°C for 3 hours without stratification and without forming a continuous oil phase; in a 1000ml beaker, according to the method of application example 1 , add 1000ml of the oily waste water in 19 1000ml beakers in turn, heat to 90°C and add 570μl of oil-water separators of Examples 1-10 and 1-9 in turn, about 500mg (add at 1.1% of the oil content, each Add only one oil-water separating agent to each beaker), stir evenly, place it in a 90°C incubator for 2 hours, record the oil-water separation at 1 hour and 2 hours, and detect the oil content of the water phase after placing for 2 hours. In addition, 1000ml of the oily wastewater was added to a 1000ml beaker, heated to 90°C and directly placed in a 90°C incubator for 2h as a blank control.

The test conditions are listed in Table 3, where the oil content of the water phase is the oil content of the water sample taken from the depth of 20-30% of the liquid from the bottom of the cup.

Take 10ml of the continuous oil phase collected from the waste water treated by the oil-water separator in Examples 1-10, mix well, measure the water content of 0.23m%, and the salt content of less than 3mg/L.

Table 3 The treatment effect of each oil-water separator on 46g/L crude oil electric desalination wastewater at 90℃, the addition amount is 500mg/L

.

Application example 3

Take the oily wastewater discharged from a heavy and inferior crude oil electric desalination device, the oil content is 150g/L, it is sealed at room temperature or 90 ℃ for 3 hours without stratification and no continuous oil phase is formed; add 1000ml of the oily wastewater into a 1000ml beaker, and heat it to 90 ℃ and add 1700 μl of oil-water separator of Example 1 about 1500 mg, stir evenly, place it in a 90 ℃ incubator for 3 hours, record the oil-water separation at 2 hours and 3 hours, and detect the oil content of the water phase after placing for 3 hours.

According to the same method, 1000ml of the oily waste water was added to 18 1000ml beakers in turn, heated to 90°C, and 1700μl of oil-water separation agent of Example 2-10 and Comparative Example 1-9 were added in sequence. About 1500mg (according to 1.0 % addition, only one oil-water separator is added to each beaker), stir evenly and place in a 90°C incubator for 3 hours, record the oil-water separation at 2 hours and 3 hours, and detect the oil content of the water phase after being placed for 3 hours.

The test conditions are listed in Table 4, where the oil content of the water phase is the oil content of the water sample taken from the depth of 20-30% of the liquid at the bottom of the cup. In addition, 1000ml of the oily wastewater was added to a 1000ml beaker, heated to 90°C and directly placed in a 90°C incubator for 3h as a blank control.

Take 50ml of the continuous oil phase collected from the waste water treated by the oil-water separating agent in Examples 1-10, and measure the water content below 0.3m%, and measure the salt content below 3mg/L.

Table 4 The treatment effect of each oil-water separator on 150g/L crude oil electric desalination wastewater at 90℃, the addition amount is 1500mg/L

.

Application example 4

In six 1000ml beakers, add 1000ml of each of the three types of oily waste water used in Application Examples 1-3, and two cups of each oily waste water, respectively, heat to 80°C and add the oil-water separator of Example 5, stir evenly and place in 100L In the cup holder of the pressure-resistant reaction kettle, the amount of oil-water separating agent added is listed in Table 5; in addition, 1000 ml of each of the three types of oily wastewater was added to the three 1000-ml beakers, heated to 80 °C, and placed directly in the cup of the pressure-resistant reaction kettle. rack as a blank control. The outer dimensions of the nine beakers are the same, and the bottom surfaces of the beakers in the pressure-resistant reactor cup holder are at the same level. After placing the beaker, inject 80°C hot water into the reaction kettle until it is flush with the liquid level in the beaker, close the lid of the reaction kettle, fill with high-purity nitrogen to 0.6MPa, then release the pressure, and repeat the charge and discharge of high-purity nitrogen six times to replace the air. Charge high-purity nitrogen to 0.6MPa, then power on to heat up the hot water in the reactor to 140°C, keep the temperature for 1 hour, turn off the power, turn on the cooling water, cool the hot water in the reactor to 80°C, release the pressure, open the lid of the reactor, Remove nine beakers. During the operation, the time from the waste water in the first beaker adding the water separating agent to the heating of the hot water in the reactor to 140°C is 0.4h, from the opening of the cooling water to the cooling of the hot water to 80°C, pressure relief, opening the lid, The time for all the nine beakers to be taken out was 0.3h.

Check the oil-water separation in each beaker, and test each oil phase and water phase. The results are listed in Table 5.

Table 5 Treatment effect of each oil-water separator on 8.1g/L, 46g/L and 150g/L crude oil electric desalination wastewater at 140℃

.

Application example 5

In six 1000ml beakers, add 1000ml of each of the three kinds of oily wastewater at room temperature used in Application Examples 1-3, and two cups of each oily wastewater, without heating, add the oil-water separator of Example 5, stir well, and add the oil-water separator. The amount is listed in Table 6; in addition, 1000ml of each of the three types of oily waste water was added to three 1000ml beakers, respectively, without heating, without adding oil, and the water separator was used as a blank control. After standing at room temperature for 1 hour, check the oil-water separation in each beaker, and there is no visible change in the water-separating agent without adding oil; the oil-rich phase is formed in the upper layer of the oil-water separation agent, and the transparent water phase is formed below the oil-rich phase. The oil phase was taken out, placed in a small-capacity beaker and heated to 90°C and placed in a 90°C incubator for 1 hour to form a continuous oil phase. There was no foam on the oil phase, the oil-water phase interface was clear, and the water phase was transparent. The combined water phase of the oil phase, the room temperature water phase and the 90° C. water phase was tested, and the results are listed in Table 6.

Table 6 The treatment effect of each oil-water separator on the crude oil electric desalination wastewater with an oil content of 150g/L at room temperature +90℃

.

Claims (10)

1. a kind of oil-water separating agent for handling oily waste water, in terms of mass fraction, comprising two 100 parts of tertiary butyl ether of ethylene glycol, averagely 30-80 parts of the polyisobutene of molecular weight 800-1300,20-60 parts of propylene glycol diacetate, 5-20 parts of alpha-pyrrolidone.

2. oil-water separating agent as described in claim 1, which is characterized in that the polyisobutene is the poly- of average molecular weight 800 The polyisobutene of isobutene and/or average molecular weight 1300.

3. oil-water separating agent as claimed in claim 2, which is characterized in that the polyisobutene peace of the average molecular weight 800 The polyisobutene of average molecular weight 1300, the mass fraction ratio of the two are 100:(30-60).

4. oil-water separating agent as claimed in claim 2, which is characterized in that include two 100 parts of tertiary butyl ether of ethylene glycol, mean molecule 40 parts of polyisobutene, 20 parts of the polyisobutene of average molecular weight 1300,40 parts of propylene glycol diacetate, α-pyrrolidines of amount 800 10 parts of ketone.

5. oil-water separating agent as described in claim 1, which is characterized in that suitable for handling the oily waste water of oil-in-water type；With/ Or the oil includes mineral oil and bio-oil.

6. oil-water separating agent as described in claim 1, which is characterized in that oily waste water is added by the amount of 50-2000mg/L, or Person is added by the 0.5-5m% of oil content；And/or water-oil separating treatment temperature is 20-150 DEG C.

7. application of the oil-water separating agent as described in claim 1 in the arranged oiliness sewage treatment of crude electric desalter.

8. application of the oil-water separating agent as claimed in claim 7 in the arranged oiliness sewage treatment of crude electric desalter, special Sign is that the crude oil includes or comprising peracid crude oil with poor quality, weight crude oil with poor quality.

9. application of the oil-water separating agent as claimed in claim 8 in the arranged oiliness sewage treatment of crude electric desalter, special Sign is, water-oil separating processing operation is carried out under the conditions of 130-145 DEG C of temperature of crude oil electric desalting arranged oily waste water.

10. application of the oil-water separating agent as claimed in claim 8 in the arranged oiliness sewage treatment of crude electric desalter, special Sign is that the oily phase recycled when handling crude oil electric desalting waste water, crude oil goes atmospheric and vacuum distillation unit normally to add after being pumped into electro-desalting Work, or give to catalytic cracking unit or coking plant and processed.