Kitchen waste grease desalting process

Abstract

The invention relates to the technical field of grease waste treatment, and provides a kitchen waste grease desalting process which comprises the following steps: S1, filtering, crushing and separating grease to obtain treated grease; s2, adding water and an auxiliary agent into the treated grease, stirring, and carrying out oil-water separation to obtain desalted grease; the auxiliaries comprise the following components in parts by weight: 2-15 parts of calcium tartrate, 2-12 parts of diacetone acrylamide, 3-7 parts of sodium bicarbonate, 10-18 parts of organic amine, 2-4 parts of a demulsifier and 15-25 parts of activated carbon. According to the technical scheme, the problem of low salt removal efficiency in the kitchen waste grease in related technologies is solved.

Description

Technical Field

[0001] The invention relates to the technical field of waste grease treatment, and in particular to a process for desalting waste kitchen grease. Background Art

[0002] The salt in waste cooking oil usually exists in the form of inorganic salts such as sodium chloride, but there are also some other chloride salts. These salts will partially dissolve in the small amount of water contained in the oil, or adhere to the surface of the oil in the form of tiny particles, and thus exist in the waste cooking oil. When recycling waste cooking oil, it is usually necessary to separate the oil from other impurities, and the presence of salt will interfere with the further processing of the waste cooking oil. For example, the waste cooking oil is further processed and used to produce biodiesel, and in the transesterification reaction in the biodiesel production process, salt may affect the activity of the catalyst, resulting in reduced reaction efficiency or even failure to proceed normally, thereby affecting the yield and quality of biodiesel. Furthermore, from the perspective of equipment maintenance, these chloride salts are corrosive to a certain extent. In the equipment for recycling and processing waste cooking oil, if the salt content is too high, long-term contact will corrode the metal parts of the equipment, shorten the service life of the equipment, increase the equipment maintenance cost and replacement frequency, and is not conducive to the long-term stable operation of the recycling process.

[0003] At present, electrical desalination is usually used to separate oil and salt. Electrical desalination mainly relies on the effect of electric field force on water droplets and the density difference between oil and water to achieve the desalination process. However, although this method can reduce the salt content in the medium to a certain extent, the removal efficiency is limited. Therefore, a method for efficiently removing salt from waste kitchen oil is proposed, which is of great significance for improving the recycling of oil. Summary of the invention

[0004] The invention provides a process for desalting waste cooking oil, which solves the problem of low efficiency in removing salt from waste cooking oil in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides a process for desalting waste cooking oil, comprising the following steps: S1, filtering, crushing and separating the grease to obtain treated grease; S2, adding water and an auxiliary agent to the treated grease, stirring, separating the oil and water, and obtaining desalted grease; The auxiliary agent comprises the following components in parts by weight: 2-15 parts of calcium tartrate, 2-12 parts of diacetone acrylamide, 3-7 parts of sodium bicarbonate, 10-18 parts of organic amine, 2-4 parts of demulsifier, and 15-25 parts of activated carbon.

[0006] As a further technical solution, the weight ratio of the calcium tartrate to the diacetone acrylamide is 3-6:2.

[0007] When the weight ratio of calcium tartrate to diacetone acrylamide is 3-6:2, the removal efficiency of salt in waste cooking oil can be further improved.

[0008] As a further technical solution, the activated carbon is activated carbon loaded with an aminocarboxylic acid complexing agent, and the raw materials of the activated carbon loaded with an aminocarboxylic acid complexing agent include activated carbon and an aminocarboxylic acid complexing agent.

[0009] As a further technical solution, the aminocarboxylic acid complexing agent includes iminodiacetic acid.

[0010] When the aminocarboxylic acid complexing agent includes iminodiacetic acid, by loading iminodiacetic acid on the activated carbon, the adsorption sites of the activated carbon are increased, and the activated carbon can be better dispersed in the oil system, thereby improving the adsorption effect of salt in the oil, and further improving the removal efficiency of salt in kitchen waste oil.

[0011] As a further technical solution, the weight ratio of the activated carbon to the aminocarboxylic acid complexing agent is 30:2~6.

[0012] When the weight ratio of activated carbon to aminocarboxylic acid complexing agent is 30:2~6, the removal efficiency of salt in waste cooking oil can be further improved.

[0013] As a further technical solution, the preparation method of the activated carbon loaded with aminocarboxylic acid complexing agent comprises the following steps: after dispersing the aminocarboxylic acid complexing agent in water, adding the activated carbon, impregnating, and drying to obtain the activated carbon loaded with aminocarboxylic acid complexing agent.

[0014] As a further technical solution, the aminocarboxylic acid complexing agent also includes hydroxyethyliminodiacetic acid.

[0015] The inventors have found that when the aminocarboxylic acid complexing agent also includes hydroxyethyliminodiacetic acid, the activated carbon is loaded with iminodiacetic acid and hydroxyethyliminodiacetic acid, which can further improve the removal efficiency of salt in waste kitchen grease. It is speculated that the reason may be that when the aminocarboxylic acid complexing agent also includes hydroxyethyliminodiacetic acid, hydroxyethyliminodiacetic acid can produce a synergistic effect with iminodiacetic acid, so that the effect of activated carbon on salt is further enhanced, thereby further improving the removal efficiency of salt in waste kitchen grease.

[0016] As a further technical solution, the weight ratio of the iminodiacetic acid to the hydroxyethyliminodiacetic acid is 2-5:1.

[0017] When the weight ratio of iminodiacetic acid to hydroxyethyliminodiacetic acid is 2-5:1, the removal efficiency of salt in waste cooking oil can be further improved.

[0018] As a further technical solution, during the immersion, the temperature is 50-60° C. and the time is 1-2 hours.

[0019] As a further technical solution, the demulsifier includes one or more of fatty alcohol polyoxyethylene ether, octylphenol polyoxyethylene ether, and castor oil polyoxyethylene ether.

[0020] As a further technical solution, the organic amine is one or more of ethanolamine, ethylenediamine, and 2-ethylhexylamine.

[0021] As a further technical solution, in step S1, during the filtration, a mesh is used for filtration at 50-60° C., and the pore size of the mesh is 0.1-0.15 mm.

[0022] As a further technical solution, in step S2, the amount of water added is 15% to 30% of the volume of the treated oil; in terms of g / mL, the mass volume ratio of the auxiliary agent to the treated oil is 3 to 4:2000.

[0023] As a further technical solution, in step S2, the stirring temperature is 85-95° C. and the stirring time is 2-3 hours.

[0024] The working principle and beneficial effects of the present invention are: In the present invention, water and an auxiliary agent are added to the treated grease, and the auxiliary agent includes calcium tartrate and diacetone acrylamide. Calcium tartrate and diacetone acrylamide have a synergistic effect. The combined use of calcium tartrate and diacetone acrylamide can act on waste kitchen grease to reduce the aggregation of grease in water and hydrate it. In combination with other auxiliary agents, salt in grease can be effectively separated, thereby improving the removal efficiency of salt in waste kitchen grease. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the following examples and comparative examples, the model of castor oil polyoxyethylene ether is EL-10; the activated carbon is coconut shell activated carbon, model HSQ-04, particle size is 40 mesh, specific surface area is 1500m 2 / g, packing density is 600g / cm 3 .

[0027] Example 1 A process for desalting waste cooking oil comprises the following steps: S1, filtering the oil at 50°C using a sieve with a pore size of 0.1 mm, crushing and separating the oil to obtain treated oil; S2, adding water and additives to the treated oil, stirring at 85°C for 3 hours, separating the oil and water, and obtaining desalted oil; The amount of water added was 15% of the volume of the treated oil; the mass volume ratio of the additive to the treated oil was 3g:2000mL; The additives include the following components in parts by weight: 2 parts of calcium tartrate, 2 parts of diacetone acrylamide, 3 parts of sodium bicarbonate, 10 parts of 2-ethylhexylamine, 2 parts of castor oil polyoxyethylene ether, and 15 parts of activated carbon.

[0028] Example 2 A process for desalting waste cooking oil comprises the following steps: S1, filtering the oil at 55°C using a sieve with a pore size of 0.15 mm, crushing and separating the oil to obtain treated oil; S2, adding water and additives to the treated oil, stirring at 90°C for 2.5h, separating the oil and water, and obtaining desalted oil; The amount of water added is 30% of the volume of the treated oil; the mass volume ratio of the additive to the treated oil is 4g:2000mL; The additives include the following components in parts by weight: 6 parts of calcium tartrate, 10 parts of diacetone acrylamide, 5 parts of sodium bicarbonate, 14 parts of 2-ethylhexylamine, 3 parts of castor oil polyoxyethylene ether, and 20 parts of activated carbon.

[0029] Example 3 A process for desalting waste cooking oil comprises the following steps: S1, filtering the oil at 60°C using a sieve with a pore size of 0.15 mm, crushing and separating the oil to obtain treated oil; S2, adding water and additives to the treated oil, stirring at 95°C for 2h to separate the oil and water to obtain desalted oil; The amount of water added was 25% of the volume of the treated oil; the mass volume ratio of the additive to the treated oil was 3.5 g:2000 mL; The additives include the following components in parts by weight: 15 parts of calcium tartrate, 12 parts of diacetone acrylamide, 7 parts of sodium bicarbonate, 18 parts of 2-ethylhexylamine, 4 parts of castor oil polyoxyethylene ether, and 25 parts of activated carbon.

[0030] Example 4 The difference between this embodiment and embodiment 2 is that, in this embodiment, 14 parts of calcium tartrate and 2 parts of diacetone acrylamide are added.

[0031] Example 5 The only difference between this embodiment and embodiment 2 is that, in this embodiment, 9.6 parts of calcium tartrate and 6.4 parts of diacetone acrylamide are added.

[0032] Example 6 The difference between this embodiment and embodiment 2 is that, in this embodiment, 12 parts of calcium tartrate and 4 parts of diacetone acrylamide are added.

[0033] Example 7 The only difference between this embodiment and embodiment 6 is that in this embodiment, the activated carbon is activated carbon loaded with an aminocarboxylic acid complexing agent, and its preparation method comprises the following steps: after dispersing 1 part of iminodiacetic acid in 15 parts of water, adding 30 parts of activated carbon, immersing at 50°C for 2h, and drying to obtain activated carbon loaded with an aminocarboxylic acid complexing agent.

[0034] Example 8 The difference between this embodiment and embodiment 7 is that, in this embodiment, 7 parts of iminodiacetic acid are added.

[0035] Example 9 The difference between this embodiment and embodiment 7 is that, in this embodiment, 2 parts of iminodiacetic acid are added.

[0036] Example 10 The difference between this embodiment and embodiment 7 is that, in this embodiment, 6 parts of iminodiacetic acid are added.

[0037] Embodiment 11 The difference between this embodiment and embodiment 10 is that, in this embodiment, iminodiacetic acid is replaced by an equal amount of hydroxyethyliminodiacetic acid.

[0038] Example 12 The only difference between this embodiment and embodiment 10 is that, in this embodiment, 6 parts of iminodiacetic acid are replaced by 3 parts of iminodiacetic acid and 3 parts of hydroxyethyliminodiacetic acid.

[0039] Example 13 The only difference between this embodiment and embodiment 10 is that, in this embodiment, 6 parts of iminodiacetic acid are replaced by 5.5 parts of iminodiacetic acid and 0.5 parts of hydroxyethyliminodiacetic acid.

[0040] Embodiment 14 The only difference between this embodiment and embodiment 10 is that, in this embodiment, 6 parts of iminodiacetic acid are replaced by 4 parts of iminodiacetic acid and 2 parts of hydroxyethyliminodiacetic acid.

[0041] Embodiment 15 The only difference between this embodiment and embodiment 10 is that, in this embodiment, 6 parts of iminodiacetic acid are replaced by 5 parts of iminodiacetic acid and 1 part of hydroxyethyliminodiacetic acid.

[0042] Comparative Example 1 The difference between this comparative example and Example 1 is that in this comparative example, no calcium tartrate is added and 4 parts of diacetone acrylamide are added.

[0043] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, no diacetone acrylamide is added, and 4 parts of calcium tartrate are added.

[0044] Comparative Example 3 The only difference between this comparative example and Example 1 is that in this comparative example, neither calcium tartrate nor diacetone acrylamide is added.

[0045] After desalting the waste cooking oil containing 35.75 mg / L NaCl and 71.46 ppm of total chlorine content by the methods of Examples 1 to 15 and Comparative Examples 1 to 3, the inorganic salt content was determined according to the method in SY / T 0536-2008 "Determination of Salt Content of Crude Oil by Coulometric Method", and the total chlorine content was tested by a microcomputer sulfur-chlorine analyzer (model ZWK-3000), wherein the electrolyte used in the total chlorine content test was high-grade pure glacial acetic acid and pure water in a volume ratio of 7:3, and the injection volume was 4 μL.

[0046] The test results are shown in Table 1 below.

[0047] Table 1 Results of determination of salt content in Examples 1 to 15 and Comparative Examples 1 to 3

[0048] Compared with Comparative Examples 1 to 3, the inorganic salt content and the total chlorine content in Example 1 are significantly reduced, indicating that when calcium tartrate and diacetone acrylamide are added to the additive, the two have a synergistic effect and can improve the removal efficiency of salt in waste kitchen oil.

[0049] Compared with Examples 2 and 4, the inorganic salt content and the total chlorine content in Examples 5-6 are reduced, indicating that when the weight ratio of calcium tartrate to diacetone acrylamide is 3-6:2, the removal efficiency of salt in waste cooking oil can be further improved.

[0050] Compared with Example 6, the inorganic salt content and the total chlorine content in Examples 7 to 10 are reduced, indicating that when the aminocarboxylic acid complexing agent is iminodiacetic acid, the removal efficiency of salt in waste cooking oil can be further improved by loading iminodiacetic acid on activated carbon.

[0051] Compared with Examples 7 to 8, the inorganic salt content and the total chlorine content in Examples 9 to 10 are reduced, indicating that when the weight ratio of activated carbon to aminocarboxylic acid complexing agent is 30:2 to 6, the removal efficiency of salt in waste cooking oil can be further improved.

[0052] Compared with Examples 10 to 11, the inorganic salt content and the total chlorine content in Examples 12 to 15 are reduced, indicating that when the aminocarboxylic acid complexing agent also includes hydroxyethyliminodiacetic acid, the activated carbon is loaded with iminodiacetic acid and hydroxyethyliminodiacetic acid, which can further improve the removal efficiency of salt in waste kitchen grease. In addition, compared with Examples 12 to 13, the inorganic salt content and the total chlorine content in Examples 14 to 15 are reduced, indicating that when the weight ratio of iminodiacetic acid and hydroxyethyliminodiacetic acid is 2 to 5:1, the removal efficiency of salt in waste kitchen grease can be further improved.

[0053] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for desalting waste cooking oil, characterized in that: The following steps are involved: S1, filtering, crushing and separating the grease to obtain treated grease; S2, adding water and an auxiliary agent to the treated grease, stirring, separating the oil and water, and obtaining desalted grease; The auxiliary agent comprises the following components in parts by weight: 2-15 parts of calcium tartrate, 2-12 parts of diacetone acrylamide, 3-7 parts of sodium bicarbonate, 10-18 parts of organic amine, 2-4 parts of demulsifier, and 15-25 parts of activated carbon.

2. A process for desalting waste cooking oil according to claim 1, characterized in that: The weight ratio of the calcium tartrate to the diacetone acrylamide is 3-6:

2.

3. A process for desalting waste cooking oil according to claim 1, characterized in that: The activated carbon is activated carbon loaded with an aminocarboxylic acid complexing agent, and the raw materials of the activated carbon loaded with an aminocarboxylic acid complexing agent include activated carbon and an aminocarboxylic acid complexing agent.

4. A process for desalting waste cooking oil according to claim 3, characterized in that: The aminocarboxylic acid complexing agent includes iminodiacetic acid.

5. A process for desalting waste cooking oil according to claim 3, characterized in that: The weight ratio of the activated carbon to the aminocarboxylic acid complexing agent is 30:2-6.

6. A process for desalting waste cooking oil according to claim 3, characterized in that: The preparation method of the activated carbon loaded with aminocarboxylic acid complexing agent comprises the following steps: dispersing the aminocarboxylic acid complexing agent in water, adding the activated carbon, impregnating, and drying to obtain the activated carbon loaded with aminocarboxylic acid complexing agent.

7. A process for desalting waste cooking oil according to claim 4, characterized in that: The aminocarboxylic acid complexing agent also includes hydroxyethyliminodiacetic acid.

8. A process for desalting waste cooking oil according to claim 7, characterized in that: The weight ratio of the iminodiacetic acid to the hydroxyethyliminodiacetic acid is 2-5:

1.

9. The process for desalting waste cooking oil according to claim 1, characterized in that: The demulsifier includes one or more of fatty alcohol polyoxyethylene ether, octylphenol polyoxyethylene ether, and castor oil polyoxyethylene ether; the organic amine is one or more of ethanolamine, ethylenediamine, and 2-ethylhexylamine.

10. The process for desalting waste cooking oil according to claim 1, characterized in that: In step S2, the amount of water added is 15% to 30% of the volume of the treated oil; in terms of g / mL, the mass volume ratio of the auxiliary agent to the treated oil is 3 to 4:2000.

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