Modified cellulose demulsifier as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of oilfield chemical auxiliaries, and discloses a modified cellulose demulsifier as well as a preparation method and application thereof. The preparation method of the modified cellulose demulsifier comprises the following steps: 1) adding cellulose into organic alkali, uniformly dispersing, adding an aminating agent, heating for reaction, filtering after the reaction is finished, and washing and drying a solid product to obtain aminated cellulose; and 2) adding the aminated cellulose into halogenated alkane, heating for reaction, filtering after the reaction is finished, and washing and drying a solid product to obtain the modified cellulose demulsifier. The modified cellulose demulsifier is obtained by taking the cellulose as a raw material and aminating and ionizing, and the modified cellulose demulsifier has the advantages of cheap and easily available raw materials, simple preparation process, no pollution, easiness in degradation, good demulsification effect, wide application range and the like, and has better application and popularization prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield chemical additives, and particularly relates to a modified cellulose demulsifier, a preparation method thereof, and an application thereof. Background Art

[0002] The petroleum industry generates a large amount of oily wastewater every year. The discharge of oily wastewater inevitably causes waste of resources, environmental and ecological problems, and even threatens human health. With the continuous increase in the production of oily wastewater in the petroleum industry, the treatment of oily wastewater has become one of the worldwide problems. At present, the demulsifiers used in China are mainly polyoxyethylene polyoxypropylene block polyethers, and the main methods for modifying them include "changing the head, changing the tail, adding a backbone, grafting, chain extension, compounding", etc. However, most of the raw materials of these demulsifiers are petroleum-based alkylphenols, which are not only expensive but also pollute water resources. Therefore, it is urgent to develop a new type of demulsifier with low cost, green environmental protection and excellent performance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a modified cellulose demulsifier, a preparation method thereof, and an application thereof in view of the deficiencies of the existing technology. The modified cellulose demulsifier is obtained by amination and ionization of cellulose as a raw material, and has many advantages such as cheap and easily available raw materials, simple preparation process, pollution-free and easy degradation, good demulsification effect, wide application range, etc., and has good application and popularization prospects.

[0004] To solve the technical problems proposed by the present invention, the present invention provides a preparation method of a modified cellulose demulsifier, comprising the following steps:

[0005] 1) Adding cellulose to an organic base, dispersing evenly and then adding an aminating agent, heating for reaction, filtering after the reaction is completed, washing and drying the solid product to obtain aminated cellulose;

[0006] 2) Adding the aminated cellulose to a halogenated alkane, heating for reaction, filtering after the reaction is completed, washing and drying the solid product to obtain a modified cellulose demulsifier.

[0007] In the above solution, the cellulose is microcrystalline cellulose.

[0008] In the above solution, the organic base is one or more of pyridine, triethylamine, and trimethylamine.

[0009] In the above solution, the mass ratio of the cellulose to the organic base is (0.01 - 0.05):1.

[0010] In the above solution, the molecular structure of the aminating agent contains both halogen and dimethylamino groups.

[0011] In the above solution, the aminating agent is one or more of 3-(dimethylamino)propyl chloride hydrochloride, 2-chloro-1-(dimethylamino)propane hydrochloride, dimethylcarbamoyl chloride, dimethylaminoacetyl chloride hydrochloride, and 4-dimethylaminobenzoyl chloride.

[0012] In the above solution, the mass ratio of the aminating agent to cellulose is (1-2):1.

[0013] In the above solution, the temperature increase in step 1) is 50-80°C, and the reaction time is 12-24 h.

[0014] In the above solution, the haloalkane is one or more of dodecyl bromide, tetradecyl bromide, hexadecyl bromide, and hexadecyl chloride.

[0015] In the above solution, the mass ratio of the haloalkane to aminated cellulose is (10-20):1.

[0016] In the above solution, the temperature increase in step 2) is 100-150°C, and the reaction time is 12-24 h.

[0017] The present invention also provides a modified cellulose demulsifier, which is prepared according to the above method.

[0018] The present invention also provides an application of the modified cellulose demulsifier in the treatment of oily wastewater. The application method is as follows:

[0019] 1) Add the modified cellulose demulsifier to water to form a dispersion of the modified cellulose demulsifier.

[0020] 2) Add the dispersion of the modified cellulose demulsifier to the oily wastewater, mix, and then let it stand.

[0021] In the above solution, the pH of the oily wastewater is 3-10, and the salinity ≤ 30000 mg / L.

[0022] In the above solution, the addition amount of the modified cellulose demulsifier in the oily wastewater is 80-200 mg / L.

[0023] In the above solution, the standing temperature is 10-30°C, and the standing time is 10-30 min.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1) The demulsifier of modified cellulose of the present invention uses cellulose as a raw material. After amination and ionization, an amphiphilic cellulose with a positive charge is obtained, which has good wettability and interfacial activity. It can quickly migrate to the oil-water interface, adsorb asphaltene and displace asphaltene, reduce the oil-water interfacial tension, soften the oil-water interface, and promote the occurrence of the demulsification process. In addition, because it has a positive charge, it can undergo electrostatic neutralization with the negatively charged oil droplets in the oily wastewater, reduce the stability of the oil droplets, and promote the occurrence of the demulsification process. Therefore, when it is applied, it shows excellent demulsification performance, and can achieve a high demulsification efficiency under the conditions of low dosage, low demulsification temperature, and short demulsification time. It can be applied to acidic and alkaline conditions, and has high salt tolerance, with good application and promotion prospects.

[0026] 2) The raw materials of the present invention are cheap and easily available, and the preparation process is simple. The prepared modified cellulose demulsifier is a solid powder, which is convenient for storage and transportation, has no toxic side effects, is easy to degrade, and has no pollution to the environment. It is a new type of demulsifier with low cost and environmental friendliness. Specific Embodiments

[0027] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments. However, the content of the present invention is not limited to the following embodiments.

[0028] Example 1

[0029] A preparation method of a modified cellulose demulsifier includes the following steps:

[0030] 1) Add 2.5 g of microcrystalline cellulose to 50 g of pyridine. After dispersing evenly, add 5 g of 3-(dimethylamino)propyl chloride hydrochloride, heat up to 50 °C and react for 24 h. After the reaction is completed, filter, wash the solid product with water and then dry to obtain aminated cellulose.

[0031] 2) Add 2.5 g of aminated cellulose to 50 g of bromododecane, heat up to 130 °C and react for 18 h. After the reaction is completed, filter, wash the solid product with alcohol and then dry to obtain the modified cellulose demulsifier.

[0032] The molecular structural formula of the modified cellulose demulsifier prepared in this example is:

[0033]

[0034] Example 2

[0035] A preparation method of a modified cellulose demulsifier includes the following steps:

[0036] 1) Add 2.5 g of microcrystalline cellulose to 60 g of triethylamine. After dispersing evenly, add 5 g of 2-chloro-1-(dimethylamino)propane hydrochloride, and raise the temperature to 60 °C for reaction for 20 h. After the reaction is completed, filter, wash the solid product with water and then dry it to obtain aminated cellulose;

[0037] 2) Add 2.5 g of aminated cellulose to 40 g of hexadecyl bromide, raise the temperature to 140 °C for reaction for 16 h. After the reaction is completed, filter, wash the solid product with alcohol and then dry it to obtain the modified cellulose demulsifier.

[0038] Example 3

[0039] A preparation method of a modified cellulose demulsifier, comprising the following steps:

[0040] 1) Add 2.5 g of microcrystalline cellulose to 80 g of pyridine. After dispersing evenly, add 4 g of dimethylcarbamyl chloride, and raise the temperature to 70 °C for reaction for 16 h. After the reaction is completed, filter, wash the solid product with water and then dry it to obtain aminated cellulose;

[0041] 2) Add 2.5 g of aminated cellulose to 50 g of dodecyl chloride, raise the temperature to 150 °C for reaction for 12 h. After the reaction is completed, filter, wash the solid product with alcohol and then dry it to obtain the modified cellulose demulsifier.

[0042] Example 4

[0043] A preparation method of a modified cellulose demulsifier, comprising the following steps:

[0044] 1) Add 2.5 g of microcrystalline cellulose to 50 g of pyridine. After dispersing evenly, add 5 g of 4-dimethylaminobenzoyl chloride, and raise the temperature to 50 °C for reaction for 24 h. After the reaction is completed, filter, wash the solid product with water and then dry it to obtain aminated cellulose;

[0045] 2) Add 2.5 g of aminated cellulose to 45 g of dodecyl bromide, raise the temperature to 150 °C for reaction for 12 h. After the reaction is completed, filter, wash the solid product with alcohol and then dry it to obtain the modified cellulose demulsifier.

[0046] Example 5

[0047] A preparation method of a modified cellulose demulsifier, comprising the following steps:

[0048] 1) Add 2.5 g of microcrystalline cellulose to 100 g of pyridine. After dispersing evenly, add 3 g of dimethylaminoacetyl chloride hydrochloride, and raise the temperature to 70 °C for reaction for 24 h. After the reaction is completed, filter, wash the solid product with water and then dry it to obtain aminated cellulose;

[0049] 2) Add 2.5 g of aminated cellulose to 35 g of dodecyl bromide, heat up to 145 °C and react for 12 h. After the reaction, filter, wash the solid product with alcohol and dry it to obtain the modified cellulose demulsifier.

[0050] Application Example 1

[0051] Add 5 parts by weight of crude oil to 495 parts by weight of deionized water, stir and mix, heat to 60 °C, and then stir at a speed of 11000 r / min for 20 min to obtain stable oily wastewater (oil-in-water emulsion).

[0052] Apply the modified cellulose demulsifiers prepared in Examples 1-5 to the above-mentioned treatment of oily wastewater:

[0053] 1) Add the modified cellulose demulsifiers of each example to water respectively to prepare a modified cellulose demulsifier dispersion with a mass fraction of 0.3%;

[0054] 2) Add each modified cellulose demulsifier dispersion to 20 times the volume of oily wastewater respectively, shake well and mix evenly, and then let it stand at 20 °C for 30 min.

[0055] Use a spectrophotometer to measure the light transmittance of the separated aqueous phase to characterize the demulsification efficiency. The results are shown in Table 1.

[0056] Table 1

[0057] Group Demulsifier concentration (mg / L) Transmittance (%) Example 1 150 88.9 Example 2 150 85.1 Example 3 150 84.8 Example 4 150 86.6 Example 5 150 87.2

[0058] As can be seen from Table 1, the modified cellulose demulsifiers prepared in Examples 1-5 of the present invention have a high demulsification efficiency in oily wastewater.

[0059] Application Example 2

[0060] Add 5 parts by weight of crude oil to 495 parts by weight of deionized water, stir and mix, heat to 60 °C, and then stir at a speed of 11000 r / min for 20 min to obtain stable oily wastewater (oil-in-water emulsion).

[0061] Apply the modified cellulose demulsifier prepared in Example 1 to the above-mentioned treatment of oily wastewater:

[0062] 1) Take three portions of the modified cellulose demulsifier and add them to water respectively to prepare modified cellulose demulsifier dispersions with mass fractions of 0.4%, 0.3%, and 0.2%;

[0063] 2) Add each modified cellulose demulsifier dispersion to 20 times the volume of oily wastewater respectively, shake well and mix evenly, and then let it stand at 20 °C for 30 min.

[0064] The light transmittance of the separated aqueous phase was measured using a spectrophotometer to characterize the demulsification efficiency, and the results are shown in Table 2.

[0065] Table 2

[0066] Group Demulsifier concentration (mg / L) Transmittance (%) Test group 1 200 87.2 Test group 2 150 88.9 Test group 3 100 81.5

[0067] As can be seen from Table 2, when the dosage of the modified cellulose demulsifier prepared in the present invention in the oily wastewater is 100 - 200 mg / L, a relatively high demulsification efficiency can be achieved.

[0068] Application Example 3

[0069] 5 parts by weight of crude oil was added to 495 parts by weight of deionized water and stirred. The pH value was adjusted by adding hydrochloric acid or sodium hydroxide, and then heated to 60 °C and stirred at a speed of 11000 r / min for 20 min to obtain stable oily wastewater (oil-in-water emulsion).

[0070] The modified cellulose demulsifier prepared in Example 1 was applied to the treatment of the above-mentioned oily wastewater:

[0071] 1) Five portions of the modified cellulose demulsifier were respectively added to water to prepare a modified cellulose demulsifier dispersion with a mass fraction of 0.3%;

[0072] 2) Each modified cellulose demulsifier dispersion was respectively added to 20 times the volume of the oily wastewater, shaken well and mixed evenly, and then left to stand at 20 °C for 30 min.

[0073] The light transmittance of the separated aqueous phase was measured using a spectrophotometer to characterize the demulsification efficiency, and the results are shown in Table 3.

[0074] Table 3

[0075]

[0076]

[0077] As can be seen from Table 3, the modified cellulose demulsifier prepared in the present invention has a relatively high demulsification efficiency under both acidic and alkaline conditions.

[0078] Application Example 4

[0079] 5 parts by weight of crude oil was added to 495 parts by weight of deionized water and stirred. The salinity was adjusted by adding sodium chloride, and then heated to 60 °C and stirred at a speed of 11000 r / min for 20 min to obtain stable oily wastewater (oil-in-water emulsion).

[0080] The modified cellulose demulsifier prepared in Example 1 was applied to the treatment of the above-mentioned oily wastewater:

[0081] 1) Take six portions of the modified cellulose demulsifier and add them into water respectively to prepare a modified cellulose demulsifier dispersion with a mass fraction of 0.3%.

[0082] 2) Add each modified cellulose demulsifier dispersion into 20 times the volume of oily wastewater respectively, shake well and mix evenly, and then let it stand at 20 °C for 30 min.

[0083] Use a spectrophotometer to measure the light transmittance of the separated aqueous phase to characterize the demulsification efficiency. The results are shown in Table 4.

[0084] Table 4

[0085] Group Salinity (mg / L) Transmittance (%) Test group 9 0 88.9 Test group 10 5000 88.1 Test group 11 10000 87.7 Test group 12 15000 86.9 Test group 13 20000 86.4 Test group 14 25000 85.8

[0086] As can be seen from Table 4, the modified cellulose demulsifier prepared in the present invention has a very high demulsification efficiency under high salinity conditions, indicating that the demulsifier has high salt resistance.

[0087] Therefore, the modified cellulose demulsifier provided by the present invention has the characteristics of low dosage, low demulsification temperature, short demulsification time, high demulsification efficiency, etc., and has no toxic and side effects, is easy to degrade, has no pollution to the environment, can be applied to acidic and alkaline conditions, and has high salt tolerance.

[0088] The above embodiments are merely examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. Preparation method of a modified cellulose demulsifier, characterized in that, it comprises the following steps: 1) Add cellulose to an organic base, after dispersing evenly, add an aminating agent, raise the temperature for reaction, after the reaction ends, filter, wash and dry the solid product to obtain aminated cellulose; 2) Add the aminated cellulose to a halogenated alkane, raise the temperature for reaction, after the reaction ends, filter, wash and dry the solid product to obtain the modified cellulose demulsifier.

2. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the cellulose is microcrystalline cellulose; the organic base is one or more of pyridine, triethylamine, and trimethylamine; the molecular structure of the aminating agent contains both halogen and dimethylamino.

3. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the aminating agent is one or more of 3-(dimethylamino)chloropropane hydrochloride, 2-chloro-1-(dimethylamino)propane hydrochloride, dimethylcarbamoyl chloride, dimethylaminoacetyl chloride hydrochloride, and 4-dimethylaminobenzoyl chloride.

4. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the mass ratio of the cellulose to the organic base is (0.01-0.05):1; the mass ratio of the aminating agent to the cellulose is (1-2):

1.

5. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the halogenated alkane is one or more of dodecyl bromide, tetradecyl bromide, hexadecyl bromide, and hexadecyl chloride; the mass ratio of the halogenated alkane to the aminated cellulose is (10-20):

1.

6. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the temperature increase in step 1) is 50-80°C, and the reaction time is 12-24h.

7. The preparation method of the modified cellulose demulsifier according to claim 1, characterized in that, the temperature increase in step 2) is 100-150°C, and the reaction time is 12-24h.

8. A modified cellulose demulsifier prepared by the method according to any one of claims 1-7.

9. Application of the modified cellulose demulsifier as claimed in claim 8 in the treatment of oily wastewater.

10. The application of the modified cellulose demulsifier in the treatment of oily wastewater according to claim 9, characterized in that, the pH of the oily wastewater is 3-10, and the salinity ≤ 30000 mg / L; the addition amount of the modified cellulose demulsifier in the oily wastewater is 80-200 mg / L.

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