Dehydration methods for marine waste oil

Abstract

This application proposes a method for dehydrating ship waste oil, comprising: heating the ship waste oil to 80℃~90℃; adding a demulsifier to the heated ship waste oil and stirring to obtain a mixture; wherein the demulsifier includes an organic amine, and the organic amine includes dodecylamine; and allowing the mixture to stand at a constant temperature of 80℃~90℃ to obtain an upper oil sample and a bottom water layer, wherein the water content of the upper oil sample is less than or equal to 0.4%. This application, by heating the ship waste oil before adding the demulsifier (dodecylamine) and stirring, followed by standing at a constant temperature of 80℃~90℃, can accelerate the stratification of the upper oil sample and the bottom water layer, significantly shortening the standing time to the range of 12h~19.5h. Simultaneously, it can further reduce the water content of the recovered surface oil to less than 0.4%, meeting the requirements for moisture content (≤0.5%) in national standards GB 17411-2015RME or RMG180. The recovered surface oil can be used as boiler fuel.

Description

Technical Field

[0001] This application relates to the field of marine waste oil recycling technology, and more particularly to a method for dehydrating marine waste oil. Background Technology

[0002] Ship waste oil mainly consists of waste oil generated from the purification of marine fuel oil, fuel oil replaced during main engine maintenance, and diesel fuel. Normally, ship waste oil is stored in the ship's oil tanks. When the ship docks, a qualified hazardous waste cleanup company will extract the waste oil from the tanks and transfer it to a hazardous waste company for treatment (dehydration). After treatment by a professional hazardous waste company, the oily wastewater can be discharged after meeting treatment standards, and the separated oil phase (ship waste oil) can be used by the hazardous waste company.

[0003] However, after preliminary oil-water separation by the hazardous waste company, the ash content of the ship's waste oil was 3%-5%, and the water content was 3%-20%. The water content was still relatively high, failing to achieve the desired effect, and the treatment time was also long. Summary of the Invention

[0004] In view of this, this application proposes a method for dehydrating ship waste oil to reduce its water content and shorten the processing time.

[0005] A method for dehydrating ship waste oil includes the following steps: heating the ship waste oil to 80℃~90℃; adding a demulsifier to the heated ship waste oil and stirring to obtain a mixture; wherein the demulsifier includes an organic amine, and the organic amine includes dodecyl primary amine; and allowing the mixture to stand at a constant temperature of 80℃~90℃ to obtain an upper oil sample and a bottom water layer, wherein the water content of the upper oil sample is less than or equal to 0.4%.

[0006] In one embodiment, the amount of demulsifier added is 2% to 5% of the mass of the ship waste oil.

[0007] In one embodiment, the constant temperature settling time is 12h to 19.5h.

[0008] In one embodiment, the stirring time is 10 min to 20 min.

[0009] In one embodiment, the dehydration method further includes: separating the upper oil sample and the bottom water layer, and allowing the bottom water layer to stand to obtain a secondary oil sample and residue, wherein the water content of the secondary oil sample is less than or equal to 0.4%.

[0010] In one embodiment, the bottom water layer is kept at a constant temperature of 80°C to 90°C for 4.5 to 10 hours.

[0011] In one embodiment, the dehydration method further includes: evaporating, filtration, and incinerating the residue.

[0012] In one embodiment, the dehydration method further includes: separating the secondary oil sample and the residue, and allowing the secondary oil sample to stand to obtain a tertiary oil sample and bottom residue, wherein the water content of the tertiary oil sample is less than or equal to 0.2%.

[0013] In one embodiment, the secondary oil sample is kept at a constant temperature of 80°C to 90°C.

[0014] In one embodiment, the secondary oil sample is left to stand for 19 to 24 hours.

[0015] This application involves heating ship waste oil before adding a demulsifier (dodecylamine) and stirring. The mixture is then kept at a constant temperature of 80℃–90℃, which accelerates the stratification of the upper oil layer and the bottom water layer. This significantly shortens the constant temperature settling time to the range of 12h–19.5h. Simultaneously, it further reduces the water content of the recovered surface oil to below 0.4%, meeting the moisture content requirements (≤0.5%) in national standards GB 17411-2015RME or RMG180. The recovered surface oil can be used as boiler fuel. Detailed Implementation

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this application belong. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application.

[0017] This application proposes a method for dehydrating marine waste oil, including steps S10 to S30. It is understood that the numbering of the steps is intended to clearly describe the specific preparation method and is not a limitation on the order of the steps.

[0018] S10: Heat the waste oil from ships to 80℃~90℃;

[0019] S20: Add a demulsifier to heated ship waste oil and stir to obtain a mixture; wherein the demulsifier includes an organic amine, which may be, but is not limited to, dodecyl primary amine;

[0020] S30: The mixture is kept at a constant temperature of 80℃~90℃ to obtain an upper oil sample and a bottom water layer, wherein the water content of the upper oil sample is less than or equal to 0.4%.

[0021] Dodecyl primary amine (molecular formula CH3(CH2)) 11NH2 (CAS No.: 124-22-1), also known as 1-aminododecane, laurylamine, dodecylamine, etc., is weakly basic and can form salts with inorganic or organic acids. Dodecyl primary amine demulsifiers can rapidly penetrate the external phase of an oil-water emulsion and disperse at the oil-water interface at temperatures between 80℃ and 90℃, replacing or neutralizing the emulsifier (a component in ship waste oil), reducing the interfacial tension and interfacial film strength of the emulsion droplets, and disrupting the colloidal stability system. Simultaneously, the positively charged demulsifier dispersed at the oil-water interface neutralizes the negative charge adsorbed on the surface of the water droplets, reducing the electrostatic repulsion between the water droplets in the emulsion, causing the droplets to coagulate and merge, increasing particle size, and finally separating from the oil phase as free water. Because its specific gravity is greater than that of oil, it sinks, thus achieving the purpose of separating impurities and water.

[0022] In some embodiments, before step S10, the ship waste oil can be pretreated by letting it stand for about 24 hours to remove impurities.

[0023] In some embodiments, in step S20, the amount of demulsifier added is 2% to 5% of the mass of the waste oil. For example, the amount of demulsifier added can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc., which will not be listed here. Adding demulsifier in the range of 2% to 5% can improve the dehydration effect, ensuring that the water content in the resulting oil phase is less than or equal to 0.4%, meeting the requirements for moisture content (≤0.5%) in national standards GB 17411-2015RME or RMG180, while also controlling raw material costs.

[0024] In some embodiments, the stirring time in step S20 may be 10 min to 20 min.

[0025] In some embodiments, the isothermal settling time in step S30 is 12h to 19.5h. The demulsification effect is enhanced with prolonged isothermal settling, but after 19 hours, the improvement in demulsification effect is no longer significant, and the decrease in water content of the upper oil sample is limited. In some embodiments, the upper oil sample is also referred to as surface oil.

[0026] In some embodiments, due to the varying initial water content of the waste oil, the mixture may separate into two or three layers after being kept at a constant temperature in step S30, but the uppermost layer is always the oil phase. When the mixture separates into two layers after being kept at a constant temperature, the bottom water layer described in this application is the second layer beneath the upper oil sample. When the mixture separates into three layers after being kept at a constant temperature, the bottom water layer described in this application consists of the second and third layers beneath the upper oil sample.

[0027] In some embodiments, the dehydration method further includes step S40: separating the upper oil sample and the bottom water layer from step S30 (the upper oil sample can be transferred to another container), and allowing the bottom water layer to remain still to obtain a secondary oil sample and residue. The water content of the secondary oil sample is less than or equal to 0.4%. After transferring the upper oil sample, the bottom water layer can continue to separate under the action of a demulsifier to obtain a secondary oil sample and residue. The secondary oil sample is located on top of the residue. In some embodiments, step S40 may also be omitted.

[0028] Furthermore, in step S40, the bottom water layer is kept at a constant temperature of 80℃~90℃ for 4.5h~10h.

[0029] Furthermore, the residue in step S40 can be treated by evaporation, pressure filtration, or incineration. The residue is heated to 100℃~120℃ and evaporated at normal pressure to produce water vapor, which can be treated by wastewater treatment processes before being discharged. The remaining residue after evaporation can be pressure filtered and then incinerated.

[0030] In some embodiments, the dehydration method further includes step S50: separating the secondary oil sample and the residue (the secondary oil sample may be transferred to another container), and allowing the secondary oil sample to stand again to obtain a tertiary oil sample and bottom residue, wherein the water content of the tertiary oil sample is less than or equal to 0.2%. In some embodiments, step S50 may also be omitted.

[0031] Furthermore, in step S50, the secondary oil sample is kept at a constant temperature of 80℃~90℃.

[0032] Furthermore, in step S50, the time for the secondary oil sample to stand is 19h to 24h.

[0033] Furthermore, the bottom slag in step S50 can be treated by evaporation, pressure filtration, or incineration. The bottom slag is heated to 100℃~120℃ and evaporated at normal pressure to produce water vapor, which can be treated by wastewater treatment processes before being discharged. The remaining bottom slag after evaporation can be pressure filtered and then incinerated.

[0034] In some embodiments, the upper oil sample obtained in step S30, the secondary oil sample obtained in step S40, and the tertiary oil sample obtained in step S50 can all be used as boiler fuel.

[0035] The present application will be further described below with reference to specific embodiments and comparative examples.

[0036] Example 1

[0037] In this embodiment, a mixed oil sample of ship waste oil from Yantian and Dachang Bay ports in Shenzhen was selected, and the water content (mass percentage) of the ship waste oil was determined to be 14% to 18% using the GB / T260 method for determining the moisture content of petroleum products mentioned in national standards GB17411-2015RME or RMG180.

[0038] S10: Weigh 3630g of waste oil from the ship and heat it to 90℃;

[0039] S20: Add 181.5g (5%) of demulsifier (dodecylamine) to the heated ship waste oil and stir for 10 minutes to obtain a mixture;

[0040] S30: The mixture is allowed to stand at a constant temperature of 90°C for 12 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer is 1877.9 g, and the mass of the bottom water layer is 1863 g. The water content of the upper oil layer, determined according to the test method of GB / T260, is 0.4%.

[0041] S40: Transfer the upper oil sample to another container, and let the bottom water layer stand for another 10 hours to obtain a secondary oil sample (surface oil) and residue. The secondary oil sample has a mass of 1131.3 g, and the residue has a mass of 720.2 g. According to the test method of GB / T260, the water content of the secondary oil sample is 0.36%.

[0042] S50: Transfer the secondary oil sample to another container and let it stand for another 19 hours to obtain a tertiary oil sample (surface oil) and bottom residue. The mass of the tertiary oil sample is 895.1 g, and the mass of the bottom residue is 224.2 g. The water content of the tertiary oil sample, determined according to the test method of GB / T260, is 0.18%.

[0043] In this embodiment, the water content of the final upper oil sample (surface oil) and the third oil sample (surface oil) were 0.4% and 0.18%, respectively, both meeting the requirements for moisture content (≤0.5%) in national standards GB 17411-2015RME or RMG180, and can be used as boiler fuel. The yield of surface oil in this embodiment was 76.39% ((1877.9+895.1) / 3630).

[0044] Example 2

[0045] The waste oil sample from this embodiment is the same as the waste oil sample from Example 1.

[0046] S10: Weigh 2016.6g of waste oil from the ship and heat it to 85℃;

[0047] S20: Add 40g (2%) of demulsifier (dodecylamine) to the heated ship waste oil and stir for 20 minutes to obtain a mixture;

[0048] S30: The mixture is allowed to stand at a constant temperature of 85°C for 19 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer is 994.4 g, and the mass of the bottom water layer is 1041.1 g. The water content of the upper oil layer, determined according to the test method of GB / T260, is 0.3%.

[0049] In this embodiment, the final upper oil sample (surface oil) has a water content of 0.3%, which meets the requirements for moisture content (≤0.5%) in national standards GB17411-2015RME or RMG180, and can be used as boiler fuel.

[0050] Example 3

[0051] The waste oil sample from this embodiment is the same as the waste oil sample from Example 1.

[0052] S10: Weigh 1995.2g of waste oil from the ship and heat it to 80℃;

[0053] S20: Add 100g (5%) of demulsifier (dodecylamine) to the heated ship waste oil and stir for 15 minutes to obtain a mixture;

[0054] S30: The mixture is allowed to stand at 80°C for 19.5 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer is 980 g, and the mass of the bottom water layer is 1090.4 g. The water content of the upper oil layer, determined according to the test method of GB / T260, is 0.28%.

[0055] In this embodiment, the final upper oil sample (surface oil) has a water content of 0.28%, which meets the requirements for moisture content (≤0.5%) in national standards GB17411-2015RME or RMG180, and can be used as boiler fuel.

[0056] Comparative Example 1

[0057] The waste oil sample used in this comparative example is the same as the waste oil sample used in Example 1.

[0058] S10: Weigh 415g of waste oil from the ship and heat it to 90℃;

[0059] S20: The heated ship waste oil was allowed to stand at a constant temperature of 90℃ for 32 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer was 214.5 g, and the mass of the bottom water layer was 197.8 g. The water content of the upper oil layer was determined to be 0.48% according to the test method of GB / T260.

[0060] Comparative Example 2

[0061] The waste oil sample used in this comparative example is the same as the waste oil sample used in Example 1.

[0062] S10: Weigh 2000g of waste oil from the ship and heat it to 85℃;

[0063] S20: The heated ship waste oil was allowed to stand at 85℃ for 37 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer was 1058g, and the mass of the bottom water layer was 932.2g. The water content of the upper oil layer was determined to be 0.38% according to the test method of GB / T260.

[0064] Comparative Example 3

[0065] The waste oil sample used in this comparative example is the same as the waste oil sample used in Example 1.

[0066] S10: Weigh 1968.1g of waste oil from the ship and heat it to 80℃;

[0067] S20: The heated ship waste oil was allowed to stand at 80℃ for 36 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer was 1012g, and the mass of the bottom water layer was 944g. The water content of the upper oil layer was determined to be 0.38% according to the test method of GB / T260.

[0068] Comparative Example 4

[0069] The waste oil sample used in this comparative example is the same as the waste oil sample used in Example 1.

[0070] S10: Weigh 1961g of waste oil from the ship and heat it to 90℃;

[0071] S20: The heated ship waste oil was allowed to stand at a constant temperature of 90℃ for 37 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer was 1004.8 g, and the mass of the bottom water layer was 871.1 g. The water content of the upper oil layer was determined to be 0.38% according to the test method of GB / T260.

[0072] Comparative Example 5

[0073] The waste oil sample used in this comparative example is the same as the waste oil sample used in Example 1.

[0074] S10: Weigh 1850g of waste oil from the ship and heat it to 90℃;

[0075] S20: The heated ship waste oil was allowed to stand at a constant temperature of 90℃ for 34.5 hours to obtain an upper oil layer and a bottom water layer. The mass of the upper oil layer was 1331.4 g, and the mass of the bottom water layer was 508.7 g. The water content of the upper oil layer was determined to be 0.38% according to the test method of GB / T260.

[0076] As can be seen from Examples 1-3 and Comparative Examples 1-5, although heating and then isothermal settling of the ship's waste oil in Comparative Examples 1-5 can yield a top layer oil sample with a water content of less than or equal to 0.48%, the isothermal settling time in Comparative Examples 1-5 is over 32 hours, which is relatively long and results in low recovery efficiency. In contrast, in Examples 1-3, the addition of a demulsifier (dodecylamine) significantly shortened the isothermal settling time to within 19.5 hours, and the water content of the top layer oil could be further reduced to less than 0.4%.

[0077] This application involves heating ship waste oil before adding a demulsifier (dodecylamine) and stirring. The mixture is then kept at a constant temperature of 80℃–90℃, which accelerates the stratification of the upper oil layer and the bottom water layer. This significantly shortens the constant temperature settling time to the range of 12h–19.5h. Simultaneously, it further reduces the water content of the recovered surface oil to below 0.4%, meeting the moisture content requirements (≤0.5%) in national standards GB 17411-2015RME or RMG180. The recovered surface oil can be used as boiler fuel.

[0078] The above description describes some specific embodiments of this application, but in actual applications, the application should not be limited to these embodiments. For those skilled in the art, other modifications and alterations made based on the technical concept of this application should fall within the protection scope of this application.

Claims

1. A method for dehydrating ship waste oil, characterized in that, Includes the following steps: Heat the waste oil from ships to 80℃~90℃; A demulsifier is added to heated marine waste oil and stirred to obtain a mixture; wherein the demulsifier comprises an organic amine, and the organic amine comprises dodecyl primary amine; The mixture is kept at a constant temperature of 80℃~90℃ to obtain an upper oil sample and a bottom water layer. The water content of the upper oil sample is less than or equal to 0.4wt%, and the constant temperature standing time is 12 h~19.5 h. The upper oil sample and the bottom water layer are separated, and the bottom water layer is allowed to stand to obtain a secondary oil sample and residue. The water content of the secondary oil sample is less than or equal to 0.4 wt%.

2. The method for dehydrating ship waste oil as described in claim 1, characterized in that, The amount of demulsifier added is 2% to 5% of the mass of the waste oil from the ship.

3. The method for dehydrating ship waste oil as described in claim 1, characterized in that, The stirring time is 10 min to 20 min.

4. The method for dehydrating ship waste oil as described in claim 1, characterized in that, The bottom water layer is kept at a constant temperature of 80℃~90℃ for 4.5 h~10 h.

5. The method for dehydrating ship waste oil as described in claim 1, characterized in that, The dehydration method further includes: evaporating, filtration, and incinerating the residue.

6. The method for dehydrating ship waste oil as described in claim 1, characterized in that, The dehydration method further includes: separating the secondary oil sample from the residue, allowing the secondary oil sample to stand for a while to obtain a tertiary oil sample and bottom residue, wherein the water content of the tertiary oil sample is less than or equal to 0.2 wt%.

7. The method for dehydrating ship waste oil as described in claim 6, characterized in that, The secondary oil sample was kept at a constant temperature of 80℃~90℃.

8. The method for dehydrating ship waste oil as described in claim 6, characterized in that, The secondary oil samples were allowed to stand for 19 to 24 hours.