A method for removing phosphorus from biodiesel by oxygen-rich biomass-based porous carbon

Abstract

The application discloses a method for removing phosphorus in biodiesel by oxygen-rich biomass porous carbon, and belongs to the technical field of biological oil products. The method for preparing oxygen-rich biomass porous carbon for removing phosphorus in biodiesel comprises the following steps: mixing biomass materials and a porous framework template, performing pyrolysis gas in-situ deposition to obtain a precursor, and then removing the porous framework template in the precursor to obtain the oxygen-rich biomass porous carbon. The method adopts the gaseous products after pyrolysis of biomass materials as carbon precursors, and the biomass pyrolysis and the gaseous deposition process are simultaneously performed during preparation, so that the oxygen-rich biomass porous carbon with high specific surface area, developed pores, coexisting micropores and mesopores and high oxygen content can be finally prepared. The method for removing phosphorus in biodiesel disclosed by the application is simple, fast and low in cost, and remarkably improves the removal effect of phosphorus in biodiesel, and is a potential method for removing phosphorus in biodiesel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological oil, in particular to a method for removing phosphorus in biodiesel by oxygen-rich biomass porous carbon. BACKGROUND

[0002] Biodiesel, as a near-zero carbon emission green energy, is a renewable clean energy with the most potential to replace fossil fuels in internal combustion engines. However, the raw material cost of biodiesel is relatively high, accounting for 70-85% of the total production cost, which has become one of the main obstacles to the commercialization of biodiesel. Current studies have shown that using non-refined oil as raw material can reduce the production cost of biodiesel, but the high phospholipid content in non-refined oil will lead to the phosphorus content in biodiesel not meeting the relevant standards (British standard EN14214: ≤4mg·kg -1 , American Society for Testing and Materials ASTM D6751 and Chinese GB 25199: ≤10mg·kg -1 ).

[0003] Phosphorus in biodiesel can form oxide particles at high temperatures, causing catalyst "poisoning" and more seriously leading to high particulate matter emissions, increasing sulfate ash, and thus exacerbating carbon deposition and engine blockage. At present, in terms of phosphorus removal, the hydration method is low in efficiency, the acid-base method produces a large amount of wastewater, and the enzyme and membrane removal technologies are expensive and need to be further improved. Therefore, exploring a suitable method for removing phosphorus in biodiesel is an important link to solve the problem of non-compliance of phosphorus in biodiesel. SUMMARY

[0004] The present application aims to provide a method for removing phosphorus in biodiesel by oxygen-rich biomass porous carbon, to solve the above problems in the background art. The present application uses the gaseous product after pyrolysis of biomass material as a carbon precursor. During preparation, biomass pyrolysis and gas phase deposition processes are carried out simultaneously, and finally oxygen-rich biomass porous carbon with high specific surface area, developed porosity, coexistence of micropores and mesopores, and high oxygen content can be prepared. The biodiesel phosphorus removal method disclosed in the present application is simple, fast, low in cost, and significantly improves the removal effect of phosphorus in biodiesel, and is a very potential method for removing phosphorus in biodiesel.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] One of the technical solutions of the present application: a method for preparing oxygen-rich biomass porous carbon for removing phosphorus in biodiesel is provided, comprising the following steps:

[0007] Mixing the biomass material with the porous framework template, carrying out pyrolysis gas in-situ deposition to obtain a precursor, and then removing the porous framework template in the precursor to obtain the oxygen-rich biomass porous carbon.

[0008] Preferably, the porous framework template is 13X molecular sieve.

[0009] Preferably, the mass ratio of the biomass material to the porous framework template is 1-2:1.

[0010] Preferably, the pyrolysis gas in-situ deposition is: under a protective atmosphere, increasing the temperature to 900 DEG C at a temperature increasing rate of 20 DEG C / min, and then keeping the temperature for 2h.

[0011] Preferably, the method for removing the porous framework template in the precursor is: sequentially washing the precursor in 2mol / L HCl solution, 1mol / L KOH solution and 2mol / L HCl solution for 2h, and then washing with water until neutral.

[0012] The second technical scheme of the present application provides an oxygen-rich biomass porous carbon for removing phosphorus in biodiesel, which is prepared by the above preparation method.

[0013] The third technical scheme of the present application provides an application of the above oxygen-rich biomass porous carbon in the field of biodiesel phosphorus removal agents.

[0014] The fourth technical scheme of the present application provides a method for removing phosphorus from biodiesel, which comprises mixing the above oxygen-rich biomass porous carbon with biodiesel, removing phosphorus, and then filtering and separating to obtain the phosphorus-removed biodiesel.

[0015] Preferably, the temperature for removing phosphorus is 25-30 DEG C, the time is 10-15 min, and the stirring speed during the phosphorus removal is 20r / min.

[0016] Preferably, the mass ratio of the oxygen-rich biomass porous carbon to the biodiesel is 0.1-5:100.

[0017] The present application has the following beneficial technical effects:

[0018] The oxygen-rich biomass porous carbon for removing phosphorus in biodiesel disclosed in the present application aims to use the oxygen-rich biomass porous carbon to efficiently remove phosphorus from biodiesel. The biomass porous carbon prepared in the present application has high porosity, large specific surface area and good adsorption performance. Moreover, the oxygen-rich biomass porous carbon retains a high oxygen content and has more oxygen-containing functional groups (hydroxyl and carboxyl) on the surface, which can form hydrogen bonds with phosphorus and have electrostatic interaction, thereby increasing the adsorption capacity of phosphorus, and significantly improving the removal effect of phosphorus in biodiesel, and ensuring the quality of the biodiesel.

[0019] The application adopts the gaseous product after pyrolysis of biomass material as a carbon precursor, during preparation, the biomass pyrolysis and vapor deposition process are carried out simultaneously, finally, the oxygen-rich biomass porous carbon with high specific surface area, developed pores, coexistence of micropores and mesopores and high oxygen content can be prepared.

[0020] The biodiesel dephosphorization method disclosed by the application has the advantages of simple operation, rapidness, low cost and significant improvement of the dephosphorization effect of phosphorus in the biodiesel, and is a potential biodiesel dephosphorization method. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 It is a real object diagram of the oxygen-rich biomass porous carbon in Example 1.

[0023] Figure 2 It is an XPS peak separation diagram of the oxygen-rich biomass porous carbon in Example 1. DETAILED DESCRIPTION

[0024] Now, various exemplary embodiments of the present application will be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application. It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application.

[0025] In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0026] 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 the present application pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application.

[0027] As for the "comprising", "including", "having", "containing" and the like used in the present application, they are all open terms, that is, meaning containing but not limited to.

[0028] The "room temperature" in the present application is 10-30°C unless otherwise specified.

[0029] Each raw material used in the following examples and comparative examples of the present application is a commercially available product.

[0030] Example 1

[0031] Preparation of oxygen-rich biomass porous carbon for removing phosphorus in biodiesel:

[0032] Mixing the biomass material with the porous framework template, pyrolysis gas is deposited in situ to obtain a precursor, and then removing the porous framework template in the precursor to obtain the oxygen-rich biomass porous carbon.

[0033] The Jatropha seed shell is crushed to pass through a 60-mesh sieve, and then mixed with 13X type spherical molecular sieves with a diameter of 0.5-1 mm at a mass ratio of 1.5:1, placed in a crucible, and then placed in a tube furnace, heated to 900°C at a rate of 20°C / min under N2 atmosphere, and then kept for 2 h, and then naturally cooled to room temperature to obtain a precursor; the precursor is sequentially washed in 2 mol / L HCl solution, 1 mol / L KOH solution, and 2 mol / L HCl solution for 2 h, and then washed with water to neutral, dried, and ground to pass through a 60-mesh sieve to obtain the oxygen-rich biomass porous carbon.

[0034] Figure 1 It is a real object diagram of the oxygen-rich biomass porous carbon in Example 1.

[0035] Figure 2 It is an XPS peak separation diagram of the oxygen-rich biomass porous carbon in Example 1.

[0036] Example 2

[0037] Method for removing phosphorus from Jatropha biodiesel:

[0038] (1) Using an electronic balance with an accuracy of 0.0001, 0.03 g of the product of Example 1 is weighed into a 100 mL beaker containing 30 mL of Jatropha biodiesel, and mixed thoroughly by a constant temperature magnetic stirrer at a stirring speed of 20 r / min and a temperature of 25-30°C for 10 min;

[0039] (2) The liquid phase system of step (1) is transferred to a funnel provided with qualitative filter paper for filtration to obtain the Jatropha biodiesel after phosphorus removal.

[0040] Effect Example 1

[0041] The inorganic phosphorus content of the Jatropha biodiesel and the Jatropha biodiesel after phosphorus removal in Example 2 is detected respectively, and the detection operation is as follows:

[0042] Take 13 g of the sample to be tested in a 50 mL beaker, add 15 mL of the extractant (18.2 MΩ ultrapure water), seal with plastic wrap, and place in a water bath at 85°C for 30 min; after the water bath is complete, transfer to a 150 mL separatory funnel, shake well for 1.5 min, and then let it stand to separate; the lower layer is placed in a 100 mL volumetric flask, and the upper layer of oil sample is returned to the 50 mL beaker, and the same conditions are used for water bath and separation, and the "water bath-separation" operation is repeated 5 times, and the lower layer after 5 times of separation is collected in a 100 mL volumetric flask, and the 100 mL volumetric flask is diluted to the calibration line with ultrapure water;

[0043] The sample in the 100 mL volumetric flask is detected and analyzed by ion chromatography (IC), each sample is measured three times, and the average value is obtained, and the inorganic phosphorus content in the sample to be tested is obtained.

[0044] Then the formula (1) is used to calculate the phosphorus removal rate of inorganic phosphorus in Jatropha biodiesel and Jatropha biodiesel after phosphorus removal:

[0045]

[0046] In the formula, y: phosphorus removal rate, %; x0: phosphorus content in Jatropha biodiesel before treatment with oxygen-enriched biomass porous carbon, mg / L; x1: phosphorus content in Jatropha biodiesel after treatment with oxygen-enriched biomass porous carbon, mg / L. The test results are shown in Table 1.

[0047] Table 1

[0048] Before treatment After treatment Oxygen-rich biomass porous carbon dosage (g / 30 mL) 0.00 0.03 Inorganic phosphate content in Jatropha biodiesel (mg / L) 1.857 0.897 Inorganic phosphate removal rate (%) / 51.70

[0049] As can be seen from Table 1, by adding 0.03 g of oxygen-enriched biomass porous carbon to 30 mL of Jatropha biodiesel, mixing and treating thoroughly, the content of inorganic phosphate can be reduced by 51.70%, and the removal effect is obvious.

[0050] Example 2

[0051] The organic phospholipid and total phosphorus content of the Jatropha biodiesel and the Jatropha biodiesel after phosphorus removal in Example 2 are detected, and the detection operation is as follows:

[0052] Take 15 g of the sample to be tested in a 30 mL test tube, and use the Rancimat 873 biodiesel oxidation stability tester to rapidly oxidize the Jatropha biodiesel in the test tube (oxidation temperature 110°C, air flux 10 L / h, oxidation time 18 h) to obtain an oxidized sample; take 13 g of the oxidized sample in a 50 mL beaker, add 15 mL of the extracting agent (18.2 MΩ ultrapure water), seal with plastic wrap, and then place in a water bath at 85°C for 30 min; after the water bath, transfer to a 150 mL separatory funnel, shake well for 1.5 min, and then let stand to separate the layers; take the lower layer and place in a 100 mL volumetric flask, return the upper layer to the 50 mL beaker, and perform the water bath and separation under the same conditions, and repeat the water bath-separation operation 5 times; collect the lower layer after the 5 separations in a 100 mL volumetric flask, and use ultrapure water to bring the 100 mL volumetric flask to the calibration line; use ion chromatography (IC) to analyze the sample in the 100 mL volumetric flask, and obtain the contents of organic phospholipid and total phosphorus in the sample to be tested.

[0053] Then use formula (1) to calculate the phosphorus removal rate of the organic phospholipid and total phosphorus in the Jatropha biodiesel and the Jatropha biodiesel after phosphorus removal. The test results are shown in Table 2.

[0054] Table 2

[0055] Before treatment After treatment Oxygen-rich biomass porous carbon dosage (g / 30 mL) 0.00 0.03 Organic phospholipid content in Jatropha biodiesel (mg / L) 3.545 2.238 Total phosphorus content in Jatropha biodiesel (mg / L) 5.402 3.135 Organic phospholipid removal rate in Jatropha biodiesel (%) / 36.87 Total phosphorus removal rate in Jatropha biodiesel (%) / 41.97

[0056] As shown in Table 2, after adding 0.03 g of the oxygen-rich biomass porous carbon to 30 mL of the Jatropha biodiesel, 36.87% of the organic phospholipid can be removed, and 41.97% of the total phosphorus can be removed.

[0057] Comparative Example 1

[0058] Preparation of the ordinary biomass carbon:

[0059] Grind the Jatropha seed shell to pass through a 60 mesh sieve, and then place in a tube furnace, and heat to 900°C at a heating rate of 20°C / min under a N2 atmosphere, and then maintain for 2 h, and then naturally cool to room temperature to obtain the ordinary biomass carbon.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that the product of Example 1 is omitted and an equal amount of the product of Comparative Example 1 is added to obtain the Jatropha biodiesel after phosphorus removal.

[0062] Effect Example 3

[0063] Using the test method in Effect Example 1, detect the inorganic phosphorus content data in the Jatropha biodiesel after phosphorus removal in Comparative Example 2. The test results are shown in Table 3.

[0064] Table 3

[0065]

[0066]

[0067] As can be seen from Table 3, in terms of removal of inorganic phosphate from Jatropha biodiesel, the oxygen-enriched biomass porous carbon has a more prominent advantage in removal effect compared to the ordinary biomass carbon of Comparative Example 1.

[0068] Comparative Example 3

[0069] By adjusting the product of Example 1 in Example 2 to be added in an amount of 0.15, 0.6, and 1.5 g respectively, different types of dephosphorized Jatropha biodiesel were obtained.

[0070] By adjusting the product of Comparative Example 1 in Comparative Example 2 to be added in an amount of 0.15, 0.6, and 1.5 g respectively, different types of dephosphorized Jatropha biodiesel were obtained.

[0071] Effect Example 4

[0072] Using the test method in Effect Example 2, the total phosphorus content data in the dephosphorized Jatropha biodiesel in Comparative Example 3 was detected. The test results are shown in Table 4.

[0073] Table 4

[0074]

[0075] As can be seen from Table 4, as the amount of ordinary biomass carbon in Comparative Example 1 increases, the removal effect of phosphorus in Jatropha biodiesel gradually improves. When 1.50 g of ordinary biomass carbon is added to 30 mL of Jatropha biodiesel, the removal rate of phosphorus is 78.63%. However, when 0.15 g of oxygen-enriched biomass porous carbon in Example 1 is added to 30 mL of Jatropha biodiesel, the removal rate of phosphorus has reached 91.93%, and the removal effect is significant.

[0076] When 1.5 g of oxygen-enriched biomass porous carbon is added to 30 mL of Jatropha biodiesel, the removal rate of total phosphorus in biodiesel is slightly lower compared to the sample with 0.6 g of oxygen-enriched biomass porous carbon. This may be because the number of functional groups on the surface of the oxygen-enriched biomass porous carbon is limited. When the adsorption sites are occupied, the excess biomass carbon may not be able to provide enough functional groups to react with phosphorus, thereby reducing the removal rate.

[0077] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. Use of oxygen-enriched biomass-based porous carbon in the field of biodiesel dephosphorization agents, characterized in that, The preparation method of the oxygen-enriched biomass porous carbon comprises the following steps: mixing the biomass material with a porous framework template, performing pyrolysis gas in-situ deposition to obtain a precursor, and then removing the porous framework template in the precursor to obtain the oxygen-enriched biomass porous carbon; the porous framework template is 13X molecular sieve; the mass ratio of the biomass material to the porous framework template is 1-2:1; the pyrolysis gas in-situ deposition is: under a protective atmosphere, the temperature is raised to 900 DEG C at a temperature rising rate of 20 DEG C / min, and then the temperature is kept for 2h; the method for removing the porous framework template in the precursor is: the precursor is sequentially washed in 2mol / L HCl solution, 1mol / L KOH solution and 2mol / L HCl solution for 2h, and then washed with water until neutral.

2. A method for dephosphorization of biodiesel, characterized by, The oxygen-enriched biomass porous carbon is mixed with biodiesel, phosphorus removal is performed, and then filtration separation is performed to obtain the phosphorus-removed biodiesel. The preparation method of the oxygen-enriched biomass porous carbon comprises the following steps: mixing the biomass material with a porous framework template, performing pyrolysis gas in-situ deposition to obtain a precursor, and then removing the porous framework template in the precursor to obtain the oxygen-enriched biomass porous carbon; the porous framework template is 13X molecular sieve; the mass ratio of the biomass material to the porous framework template is 1-2:1; the pyrolysis gas in-situ deposition is: under a protective atmosphere, the temperature is raised to 900 DEG C at a temperature rising rate of 20 DEG C / min, and then the temperature is kept for 2h; the method for removing the porous framework template in the precursor is: the precursor is sequentially washed in 2mol / L HCl solution, 1mol / L KOH solution and 2mol / L HCl solution for 2h, and then washed with water until neutral.

3. The dephosphorization method according to claim 2, characterized by, The mass ratio of the oxygen-enriched biomass porous carbon to the biodiesel is 0.1-5:100.

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