Method for processing vegetable pitch into heavy biological fuel oil

Abstract

The invention relates to a method for processing vegetable pitch into heavy biological fuel oil, which comprises the following steps: (1) mixing vegetable pitch, a solid adsorbent and an extraction agent, stirring, centrifuging, and collecting an upper layer material, the feeding mass ratio of the vegetable pitch to the extraction agent is 100: (10-20), and the extraction agent is cyclic carbonate; (2) carrying out acid pickling and water washing on the upper-layer material, wherein the feeding mass ratio of acid for acid pickling to the vegetable pitch is not less than 0.2%; and (3) mixing the material washed in the step (2) with glycerol and straight-chain carbonate, and then reacting at 150-300 DEG C and 15-35 MPa to obtain the heavy biological fuel oil. According to the method provided by the invention, the ash content and the acid value in the vegetable pitch can be effectively reduced, and meanwhile, the content of total sediments, phosphorus and sulfur in the vegetable pitch is reduced, so that the vegetable pitch is processed into the marine fuel oil meeting the standard, and the application range of the vegetable pitch is widened.

Description

Technical Field

[0001] The invention relates to the technical field of vegetable asphalt processing, and in particular to a method for processing vegetable asphalt into heavy biofuel oil. Background Art

[0002] Plant asphalt is a renewable, green and environmentally friendly resource. It has a wide range of sources and is mainly divided into three categories, namely, downstream products of the oil and fat industry (also known as black feet), biodiesel byproducts, and downstream products of plant-based chemical alcohols. The most common plant asphalt on the market is the large amount of biological heavy oil remaining at the bottom of the tower after the crude product is distilled during the industrial biodiesel production process. It is also called plant asphalt. Its main components are fatty acid methyl esters, plant sterols, natural vitamin E, etc., and can be used as fuel oil.

[0003] Marine fuel oil is divided into distillate-type marine fuel and residual-type marine fuel. Residual-type fuel oil is an oil product with heavy fuel oil as the main component. It is a heavier residual product separated from crude oil after gasoline, coal and diesel in the process of petroleum processing. It mainly includes straight-run fuel oil remaining from atmospheric and vacuum distillation, cracking residual oil remaining after secondary device processing, and products obtained by blending these components (some light components can also be added during the blending process). The corresponding standards for residual-type marine fuel oil are GB / T 17411-2015 Marine Fuel Oil and ISO 8217-2017, which put forward index requirements for fuel oil that can be used for ships, mainly including ash content ≤0.1%, acid value ≤2.5 (in terms of KOH) / (mg / g), total sediment ≤0.1%, phosphorus content ≤15mg / kg, and sulfur content ≤0.1%.

[0004] Under the existing ship fuel oil standards and policies, biodiesel is used as a low-carbon and environmentally friendly fuel to be blended with low-sulfur fuel oil to form B24 for ship engines, which has relatively low economic efficiency. However, using bio-heavy oil, which is closer to petrochemical heavy oil in properties and cheaper, to blend ship fuel will generate huge economic and environmental value. However, bio-heavy oil has complex composition, high viscosity, and dark color, and does not meet the above-mentioned index requirements. In addition, it is difficult to recycle and has low utilization value. Therefore, upgrading low-quality bio-heavy oil into plant-based environmentally friendly fuel that meets the requirements is of great significance to the promotion of carbon emission reduction of ship fuel. Summary of the invention

[0005] The object of the present invention is to provide a method for processing vegetable pitch into heavy biofuel oil.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a method for processing plant asphalt into heavy biofuel oil, which comprises the following steps:

[0008] (1) mixing plant asphalt, a solid adsorbent and an extractant, stirring and centrifuging, and collecting the upper layer material, wherein the mass ratio of the plant asphalt to the extractant is 100:(10-20), and the extractant is a cyclic carbonate;

[0009] (2) The upper layer material is pickled and washed with water, wherein the mass ratio of the pickling acid to the vegetable asphalt is not less than 0.2%;

[0010] (3) The washed material of step (2) is mixed with glycerol and linear carbonate, and then reacted at 150° C. to 300° C. and 15 MPa to 35 MPa to obtain heavy biofuel oil.

[0011] Plant asphalt has the problems of high ash content, high acid value, high total sediment, high phosphorus content and high sulfur content, and does not meet the above-mentioned marine fuel oil index requirements (ash content ≤ 0.1%, acid value ≤ 2.5 mgKOH / g, total sediment ≤ 0.1%, phosphorus content ≤ 15 mg / kg, sulfur content ≤ 0.1%). The present invention uses cyclic carbonate as an extractant to effectively reduce the phosphorus content of plant asphalt, and is convenient for separation; by using a solid adsorbent, the total sediment and sulfur content of plant asphalt are significantly reduced; by acid washing and water washing, the ash content of plant asphalt is effectively reduced; by using glycerol and linear carbonate, the acid value of plant asphalt is reduced, and the reactants and products can be directly used as fuel oil components or additives without generating adverse by-products.

[0012] Preferably, the extractant is selected from one or more of five-membered cyclic carbonates, six-membered cyclic carbonates, and seven-membered cyclic carbonates.

[0013] In some embodiments, the extractant is selected from one or more of propylene carbonate, ethylene carbonate, trimethylene cyclocarbonate, and 2,2-dimethyltrimethylene cyclocarbonate.

[0014] Preferably, the acid used for pickling is an organic acid. Compared with inorganic acids, organic acids are milder, have a higher flash point, and have no negative effects.

[0015] In some embodiments, the organic acid is selected from one or more of oxalic acid, tartaric acid, citric acid, sulfanilic acid, gluconic acid, glycolic acid, nitrilotriacetic acid, glutamic acid diacetic acid, ethylenediaminetetraacetic acid, benzohydroxamic acid, and ethylenediaminetetraacetic acid.

[0016] Preferably, the mass ratio of the pickling acid to the vegetable asphalt is (0.2-3):100, for example, 0.2:100, 0.5:100, 1:100, 1.5:100, 2:100, 2.5:100, 3:100.

[0017] Preferably, the solid adsorbent is selected from one or more of regenerated waste clay, regenerated activated carbon, white carbon black, and anion exchange resin.

[0018] Preferably, the feed mass ratio of the plant asphalt to the solid adsorbent is 100:(5-10), for example, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10.

[0019] Preferably, the linear carbonate is one or more of diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate.

[0020] Preferably, the feed mass ratio of the plant asphalt to the linear carbonate is 100:(10-20), for example, 100:10, 100:12, 100:14, 100:16, 100:18, 100:20.

[0021] Preferably, the glycerol is glycerol from which water has been removed.

[0022] In some embodiments, the glycerol is obtained by distilling crude glycerol at 120° C. to 130° C. under vacuum conditions to remove water.

[0023] Preferably, the mass ratio of the plant asphalt to the glycerol is 100:(5-10), for example, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10.

[0024] Preferably, when the acid value of the heavy biofuel oil obtained in step (3) is greater than 2.5 mgKOH / g, step (3) is repeated until the acid value of the heavy biofuel oil is less than or equal to 2.5 mgKOH / g.

[0025] Preferably, the mass ratio of the water for washing to the vegetable asphalt is (3-5):100, for example, 3:100, 4:100, 5:100.

[0026] Preferably, the water washing temperature is 70°C to 80°C.

[0027] In some embodiments, the water washing specifically includes heating the material to be washed to 70° C. to 80° C., then pouring it into a separatory funnel, adding water, inverting it evenly and letting it stand, and finally removing water and impurities by centrifugation to obtain the washed material.

[0028] Furthermore, the standing time during the water washing process is 30 min to 60 min.

[0029] Furthermore, the centrifugal speed during the water washing process is 2000rpm to 3000rpm.

[0030] Preferably, the pickling temperature is 70°C to 80°C.

[0031] In some embodiments, the acid washing specifically comprises heating the material to be cleaned to 70-80° C., then pouring it into a separatory funnel, adding acid, inverting it evenly, and then letting it stand.

[0032] Furthermore, the standing time during the pickling process is 30 minutes to 60 minutes.

[0033] Preferably, the plant asphalt is one or more of a biodiesel by-product, a downstream product of the oil and fat industry, and a downstream product of plant-based chemical alcohol.

[0034] Preferably, the step (1) specifically comprises heating the plant asphalt to 50° C. to 70° C. and then adding the solid adsorbent and the extractant.

[0035] The present invention also provides an application of the heavy biofuel oil as described above, wherein the application comprises using the heavy biofuel oil in a low-speed marine engine.

[0036] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0037] The method provided by the present invention can effectively reduce the ash content and acid value in plant asphalt, while reducing the total sediment, phosphorus and sulfur content of plant asphalt, thereby processing plant asphalt into marine fuel oil that meets the standards and broadening the application range of plant asphalt. DETAILED DESCRIPTION

[0038] Unless otherwise specified, the raw materials mentioned below are all commercially available products or can be prepared by referring to the existing technology. The plant heavy oil (plant asphalt) is the bio-heavy oil remaining at the bottom of the tower after the crude product is distilled in the existing biodiesel production process, and its main components are fatty acid methyl ester, plant sterol, and natural vitamin E. The regenerated waste clay and regenerated activated carbon are both homemade by conventional muffle furnace high temperature treatment of laboratory waste clay and activated carbon.

[0039] In order to reduce the phosphorus content in biodiesel, the prior art will remove some phospholipids through pretreatment, and then reduce the phosphorus content of biodiesel through distillation, but it also leads to the enrichment of more phosphorus in the remaining biological heavy oil after distillation, and because it undergoes esterification, transesterification and other reactions in the middle, its existence form has also changed greatly, generating phosphorus-containing substances that are more difficult to remove. The present invention uses cyclic carbonate to dissolve non-hydratable phospholipids, which greatly reduces the phosphorus content of plant heavy oil, and the cyclic carbonate has a high density and is not miscible with plant heavy oil, which is easy to separate. Furthermore, the present invention also effectively removes other phospholipids in the product through acidification, water washing and other operations, further reducing the phosphorus content and reducing the ash content of the product. In addition, the prior art often uses low-priced alcohol esterification or sodium hydroxide for saponification and alkali refining to reduce the acid value, but the above method is easy to cause the alcohol content in the product to be too high, affecting the flash point or increasing the potassium and sodium metal content. The present invention adopts glycerol and linear carbonate to carry out joint reaction, and the reaction products mainly include fatty acid esters and glycerol carbonate, and there is no by-product that affects the use, wherein the glycerol can also be obtained by dehydrating the crude glycerol produced in the process of biodiesel production, which is low in cost and green and environmentally friendly. The heavy biofuel oil prepared by the method of the present invention meets the marine fuel oil index and is more green and environmentally friendly.

[0040] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0041] Example 1

[0042] Add vegetable heavy oil into a flask, heat it to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay and 20% of the total mass of the vegetable heavy oil in the amount of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0043] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 60 minutes, and then centrifuge it at 3000rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0044] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0045] Example 2

[0046] Add vegetable heavy oil into a flask, heat to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated activated carbon and 20% of the total mass of the vegetable heavy oil in the amount of ethylene carbonate, stir at a low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0047] Heat material 1 to 70°C and pour it into a separatory funnel. Add citric acid accounting for 3% of the total mass of the plant heavy oil, invert evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert slowly and evenly, let it stand for 60 minutes, and then centrifuge at 3000rpm for 10 minutes to collect the upper layer to obtain material 2.

[0048] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and diethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0049] Example 3

[0050] Add vegetable heavy oil into a flask, heat it to 60°C, add 5% of the total mass of the vegetable heavy oil in the form of regenerated waste clay and 10% of the total mass of the vegetable heavy oil in the form of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0051] Heat material 1 to 70°C and pour it into a separatory funnel. Add 0.5% oxalic acid accounting for the total mass of the plant heavy oil, invert evenly and let it stand for 30 minutes. Then add 3% water at 70°C accounting for the total mass of the plant heavy oil, invert evenly, let it stand for 60 minutes, and then centrifuge at 3000rpm for 10 minutes, collect the upper layer to obtain material 2.

[0052] The crude glycerol was distilled at -0.1 MPa and 120°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 10% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 5% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0053] Example 4

[0054] Add vegetable heavy oil into a flask, heat it to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay and 20% of the total mass of the vegetable heavy oil in the amount of propylene carbonate, stir at low speed for 1 hour, centrifuge at 2000 rpm for 20 minutes, collect the upper layer after separation, and obtain material 1.

[0055] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 30 minutes, and then centrifuge it at 2000rpm for 20 minutes. Collect the upper layer to obtain material 2.

[0056] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 150°C and 35 MPa to obtain modified heavy biofuel oil.

[0057] Comparative Example 1

[0058] Add vegetable heavy oil into a flask, heat it to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay and 20% of the total mass of the vegetable heavy oil in the amount of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0059] Heat material 1 to 70°C and pour it into a separatory funnel. Add 0.1% oxalic acid accounting for the total mass of the plant heavy oil, invert evenly and let it stand for 5 minutes. Then add 5% 80°C water accounting for the total mass of the plant heavy oil, invert evenly, let it stand for 60 minutes, and then centrifuge at 3000rpm for 10 minutes, collect the upper layer to obtain material 2.

[0060] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0061] Comparative Example 2

[0062] Add vegetable heavy oil into a flask, heat it to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay and 20% of the total mass of the vegetable heavy oil in the amount of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0063] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 60 minutes, and then centrifuge it at 3000rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0064] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 140°C and 8 MPa to obtain modified heavy biofuel oil.

[0065] Comparative Example 3

[0066] Add vegetable heavy oil into a flask, heat it to 70°C, add 2% of the total mass of the vegetable heavy oil in the form of regenerated waste clay and 20% of the total mass of the vegetable heavy oil in the form of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0067] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 5 minutes, and then centrifuge it at 1000 rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0068] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0069] Comparative Example 4

[0070] Add vegetable heavy oil into a flask, heat it to 70°C, add 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay and 2% of the total mass of the vegetable heavy oil in the amount of propylene carbonate, stir at low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0071] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 60 minutes, and then centrifuge it at 3000rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0072] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0073] Comparative Example 5

[0074] Add vegetable heavy oil, 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay, and 20% of the total mass of the vegetable heavy oil in the amount of ether into a flask, stir at a low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0075] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 60 minutes, and then centrifuge it at 3000rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0076] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0077] Comparative Example 6

[0078] Add vegetable heavy oil, 10% of the total mass of the vegetable heavy oil in the amount of regenerated waste clay, and 20% of the total mass of the vegetable heavy oil in the amount of n-hexane into a flask, stir at a low speed for 2 hours, centrifuge at 3000 rpm for 10 minutes, collect the upper layer after separation, and obtain material 1.

[0079] Heat material 1 to 70°C and pour it into a separatory funnel. Add oxalic acid accounting for 1% of the total mass of the plant heavy oil, invert it evenly and let it stand for 30 minutes. Then add water accounting for 5% of the total mass of the plant heavy oil and at a temperature of 80°C. Invert it slowly and evenly, let it stand for 60 minutes, and then centrifuge it at 3000rpm for 10 minutes. Collect the upper layer to obtain material 2.

[0080] The crude glycerol was distilled at -0.1 MPa and 130°C to remove water to obtain dehydrated glycerol. Material 2 was poured into a reactor, and dimethyl carbonate accounting for 20% of the total mass of the plant heavy oil and dehydrated glycerol accounting for 10% of the total mass of the plant heavy oil were added, and the reaction was carried out at 300°C and 35 MPa to obtain modified heavy biofuel oil.

[0081] The heavy biofuel oils of the above embodiments and comparative examples were evaluated for indicators and appearance, and the ash content was ≤0.1%, the acid value was ≤2.5 (in terms of KOH) / (mg / g), the total sediment was ≤0.1%, the phosphorus content was ≤15 mg / kg, and the sulfur content was ≤0.1%, which met the requirements. The results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084]

[0085] Among them, vegetable heavy oil CK is untreated vegetable heavy oil, the ash content is tested in accordance with GB / T 508, the acid value is tested in accordance with GB / T7304, the total sediment is tested in accordance with SH / T 0702, the phosphorus content is tested in accordance with IP 501, and the sulfur content is tested in accordance with GB / T17040.

[0086] As can be seen from Table 1 above, the ash content, acid value, total sediment, phosphorus content and sulfur content of the heavy biofuel oil prepared in the embodiment of the present application all meet the requirements and can be used as residual ship fuel oil.

[0087] By comparing Example 1 and Comparative Example 1, it is found that the amount of organic acid used is too low to reduce the ash content, so the amount of organic acid used cannot be too low, while too high an amount of organic acid will increase the processing cost and may also cause the acid value of the system to be too large. In summary, the amount of organic acid preferably accounts for 0.2% to 3% of the total mass of the vegetable heavy oil.

[0088] By comparing Example 1 and Comparative Example 2, it is found that glycerol and linear carbonate can synergistically reduce the acid value of the system under certain reaction conditions, but the reaction temperature and pressure are not suitable and cannot effectively reduce the acid value of the system. Preferably, the reaction temperature is 150-300°C and the reaction pressure is 15-35MPa.

[0089] By comparing Example 1 and Comparative Example 3, it is found that adding solid adsorbent helps to reduce the sulfur content of plant heavy oil. As the amount of solid adsorbent increases, the sulfur reduction effect is improved, but too much solid adsorbent will have an adverse effect on the calorific value of the fuel. Therefore, the amount of solid adsorbent preferably accounts for 5% to 10% of the total mass of the plant heavy oil.

[0090] By comparing Example 1 and Comparative Examples 4 to 6, it is found that when ether and n-hexane are used as extractants, the phosphorus content and sulfur content of the system cannot be effectively reduced, and ether and n-butane are difficult to separate from the system, which poses a safety hazard. Compared with ether and n-hexane, the addition of cyclic carbonates helps to reduce the phosphorus and sulfur content of plant heavy oils. As the amount of cyclic carbonates increases, the effect is on the rise, especially the phosphorus reduction effect, but too much cyclic carbonates will increase costs. Therefore, the amount of cyclic carbonates preferably accounts for 10% to 20% of the total mass of plant heavy oils.

[0091] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing plant asphalt into heavy biofuel oil, characterized in that: The steps include: (1) mixing plant asphalt, a solid adsorbent and an extractant, stirring and centrifuging, and collecting the upper layer material, wherein the mass ratio of the plant asphalt to the extractant is 100:(10-20), and the extractant is a cyclic carbonate; (2) The upper layer material is pickled and washed with water, wherein the mass ratio of the pickling acid to the vegetable asphalt is not less than 0.2%; (3) The washed material of step (2) is mixed with glycerol and linear carbonate, and then reacted at 150° C. to 300° C. and 15 MPa to 35 MPa to obtain heavy biofuel oil.

2. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The extractant is selected from one or more of five-membered cyclic carbonate, six-membered cyclic carbonate and seven-membered cyclic carbonate.

3. The method for processing vegetable asphalt into heavy biofuel oil according to claim 2, characterized in that: The extractant is selected from one or more of propylene carbonate, ethylene carbonate, trimethylene cyclocarbonate, and 2,2-dimethyltrimethylene cyclocarbonate.

4. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The acid used for pickling is an organic acid; and / or, The mass ratio of the acid used for pickling to the vegetable asphalt is (0.2-3):

100.

5. The method for processing vegetable asphalt into heavy biofuel oil according to claim 4, characterized in that: The organic acid is selected from one or more of oxalic acid, tartaric acid, citric acid, sulfanilic acid, gluconic acid, glycolic acid, nitrilotriacetic acid, glutamic acid diacetic acid, ethylenediaminetetraacetic acid, benzohydroxamic acid, and ethylenediaminetetraacetic acid.

6. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The solid adsorbent is selected from one or more of regenerated waste clay, regenerated activated carbon, white carbon black, and anion exchange resin; and / or, The feed mass ratio of the plant asphalt to the solid adsorbent is 100:(5-10).

7. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The linear carbonate is one or more of diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; and / or, The mass ratio of the plant asphalt to the linear carbonate is 100:(10-20).

8. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The glycerol is glycerol after dehydration; and / or, The mass ratio of the plant asphalt to the glycerol is 100:(5-10).

9. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: When the acid value of the heavy biofuel oil obtained in step (3) is greater than 2.5 mgKOH / g, step (3) is repeated until the acid value of the heavy biofuel oil is less than or equal to 2.5 mgKOH / g.

10. The method for processing vegetable asphalt into heavy biofuel oil according to claim 1, characterized in that: The plant asphalt is one or more of a biodiesel by-product, a downstream product of the oil and fat industry, and a downstream product of plant-based chemical alcohol.

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