Method for extracting industrial fuel oil from waste edible oil

Abstract

The invention belongs to the technical field of industrial fuel oil preparation, and particularly relates to a method for extracting industrial fuel oil from waste edible oil, which comprises the following steps: firstly, synthesizing a cesium phosphotungstate-cucurbituril clathrate compound catalyst, and obtaining a cesium phosphotungstate-cucurbituril clathrate compound CsPW-CB by using an ultrasonic co-dissolution method; the cesium phosphotungstate-cucurbituril clathrate CsPW-CB catalyst has a good and efficient catalytic effect on an experiment of catalyzing a waste edible oil transesterification reaction to prepare biodiesel; the maximum conversion rate of 95.1% is obtained through two experimental methods, namely a single factor method and a response surface optimization method; the reaction conditions are as follows: the dosage of the catalyst is 2wt%, the alcohol-oil ratio is 11: 1, the reaction time is 150 minutes, and the temperature is 70 DEG C; compared with the prior art, the catalyst with lower price can be self-synthesized, the production time is shortened, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial fuel preparation, and particularly relates to a method for extracting industrial fuel from waste cooking oil. Background Art

[0002] Waste cooking oil is recycled to produce valuable industrial fuel.

[0003] However, existing technologies, such as the Chinese invention patent publication number "CN1670128A," which discloses a "method for producing biodiesel from waste oils," are limited in their widespread use due to the high price and reactive chemical properties of the sodium methoxide catalyst used. Similarly, the Chinese invention patent publication number "CN1473907A," which discloses a "method for producing biodiesel," requires an esterification reaction time of 6 hours and consumes a considerable amount of mechanical energy. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for extracting industrial fuel from waste cooking oil, which can synthesize a low-cost catalyst by itself, shorten the production time, reduce production costs and improve production efficiency.

[0005] The technical solutions adopted by the present invention are as follows:

[0006] A method for extracting industrial fuel from waste cooking oil comprises the following steps:

[0007] Step 1: preparing a cesium phosphotungstate-cucurbitacin inclusion complex catalyst;

[0008] Preferably, in step 1, preparing the cesium phosphotungstate-cucurbitacin inclusion complex catalyst comprises the following steps:

[0009] Step 101: Prepare cesium phosphotungstate Cs using sodium phosphotungstate, concentrated hydrochloric acid and cesium carbonate as raw materials. 2.5 H 0.5 PW 12 O 40 ;

[0010] In step 101, phosphotungstic acid is first prepared, and the ionic formula is:

[0011]

[0012] Under magnetic stirring, 50 parts by mass of Na2WO·2H2O and 8.5 parts by mass of dipotassium hydrogen phosphate were added to 100 mL of boiling water and stirred continuously. After dissolution, 50-60 parts by mass of concentrated hydrochloric acid (density of concentrated hydrochloric acid = 1.18 g / ml) were added dropwise. After the addition of hydrochloric acid, white crystals of phosphotungstic acid began to precipitate. After the hydrochloric acid was added dropwise, the mixture was cooled to room temperature. The upper layer of liquid was poured out and the precipitate was washed with water. A sufficient amount of ether was then added, the solution was separated into layers, and the lower layer was separated using a separatory funnel. The solution was evaporated to dryness at 60°C to obtain phosphotungstic acid solid.

[0013] Then prepare cesium phosphotungstate, the reaction equation is:

[0014] H3PW 12 O 40 +1.25Cs2CO3→Cs 2.5 H 0.5 PW 12 O 40 +1.25CO2+1.25H2O;

[0015] 1.25 parts by mass of Cs2CO3 and 9.175 parts by mass of pretreated phosphotungstic acid were prepared into 0.1 mol / L and 0.08 mol / L solutions respectively; at 60 ° C, 0.1 mol / L Cs2CO3 solution was added dropwise to 0.08 mol / L H3PW at a rate of 1 mL / min. 12 O 40 The solution was stirred continuously during the whole process; after the addition, stirring was continued for 30 minutes, and then the solution was allowed to stand at room temperature for 20 hours; then the water was slowly evaporated at 60 ° C, and white solid cesium phosphotungstate Cs was obtained after 48 hours. 2.5 H 0.5 PW 12 O 40 .

[0016] Step 102: synthesizing and isolating cucurbitacin CB from glyoxal and urea raw materials;

[0017] In step 102, urea and a 40% aqueous solution of glyoxal are refluxed at a certain temperature to obtain glycoluril through a condensation reaction. The specific operation method is as follows: first, a certain amount of urea solution is prepared, and its pH is adjusted to about 2 with hydrochloric acid, and the molar ratio of urea to glyoxal is controlled to be 2:1. Then, the temperature is raised to 70° C. in a condensation reflux experimental device, and the 40% glyoxal solution is added dropwise to the urea solution at a rate of 1 ml per minute. After reacting for about 3 hours, the solution begins to separate. The white solid precipitate is collected, filtered, and the filtrate is repeatedly washed with a dilute NaOH solution and distilled water, and then dried in a vacuum oven. The method comprises the steps of: drying the mixture at 120°C in a drying oven for 3-5 hours to obtain a glycoluril monomer; dissolving the glycoluril in a certain amount of 3 mol / L hydrochloric acid, cooling the mixture to 0°C, then adding paraformaldehyde powder in a ratio of glycoluril to paraformaldehyde of 2:1, mixing the mixture thoroughly, shaking the mixture, and allowing the mixture to stand for 1 hour after gelation occurs. The mixture is then heated to 90°C and maintained at this temperature for 4 hours. After the reaction is completed, the mixture is cooled and allowed to stand, and then filtered. A large amount of acetone is added to the filtrate to produce a white precipitate. After separation and separation, a solid crystalline precipitate is formed, and the mixture is recovered and dried. The dried white solid powder is cucurbitacin (CB).

[0018] Step 103: Obtain cesium phosphotungstate-cucurbitacin inclusion complex CsPW-CB by ultrasonic co-dissolution method.

[0019] In step 103, take the amount of CB and Cs that are stored in a dry state. 2.5 H 0.5 PW 12 O 40 Prepare 0.1 mol / L aqueous solution respectively; slowly drop the phosphotungstic acid aqueous solution into the cucurbitacin aqueous solution under ultrasonic vibration, and fully ultrasonically vibrate for 3 hours; then use a rotary evaporator to evaporate the solution water at 40 ° C to obtain a white powdery substance, namely cucurbitacin and Cs 2.5 H 0.5 PW 12 O 40 inclusion complex CsPW-CB.

[0020] Step 2: The waste cooking oil raw material is filtered to remove impurities and heated to 120-160°C for dehydration to complete the raw material pretreatment;

[0021] Step 3: Add waste cooking oil to a reactor and preheat the reactor to 70°C; then add a catalyst and methanol; the catalyst is added in an amount of 1.5wt%-2.5wt% of the waste cooking oil; the methanol-to-oil ratio is 10-12:1; simultaneously turn on a water condenser and a magnetic stirrer; after reacting for 140-160 minutes, transfer the solution to a centrifuge to separate the catalyst, transfer the filtrate to a container and let it stand for 24 hours to allow most of the methanol to evaporate; after sufficient standing, the filtrate separates into two layers: a lower layer of glycerol and an upper layer of biodiesel;

[0022] Step 4: Separate the upper layer of biodiesel; use distilled water to wash away a small amount of methanol, saponification and glycerol in the biodiesel; use a rotary evaporator to remove water and methanol in the biodiesel to obtain pure biodiesel.

[0023] The technical effects achieved by the present invention are:

[0024] In the present invention, CsPW-CB has a good and efficient catalytic effect in an experiment of catalyzing the transesterification reaction of waste cooking oil to prepare biodiesel. Through two experimental methods, single factor and response surface optimization, a maximum conversion rate of 95.1% was obtained. At this time, the reaction conditions are: catalyst dosage of 2wt%, alcohol-to-oil ratio of 11:1, reaction time of 150 minutes, and temperature of 70°C. Compared with the existing technology, the catalyst can be synthesized independently at a lower price, and the production time and cost are shortened, while the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The gas chromatogram of biodiesel obtained by the method of extracting industrial fuel from waste cooking oil according to the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following examples. It should be understood that the following text is only used to describe one or more specific embodiments of the present invention and does not strictly limit the scope of protection of the present invention.

[0027] like Figure 1 As shown, a method for extracting industrial fuel from waste cooking oil comprises the following steps:

[0028] Step 1: preparing a cesium phosphotungstate-cucurbitacin inclusion complex catalyst;

[0029] Preferably, in step 1, preparing the cesium phosphotungstate-cucurbitacin inclusion complex catalyst comprises the following steps:

[0030] Step 101: Prepare cesium phosphotungstate Cs using sodium phosphotungstate, concentrated hydrochloric acid and cesium carbonate as raw materials. 2.5 H0.5 PW 12 O 40 ;

[0031] In step 101, phosphotungstic acid is first prepared, and the ionic formula is:

[0032]

[0033] Under magnetic stirring, 50 parts by mass of Na2WO·2H2O and 8.5 parts by mass of dipotassium hydrogen phosphate were added to 100 mL of boiling water and stirred continuously. After dissolution, 50-60 parts by mass of concentrated hydrochloric acid (density of concentrated hydrochloric acid = 1.18 g / ml) were added dropwise. After the addition of hydrochloric acid, white crystals of phosphotungstic acid began to precipitate. After the hydrochloric acid was added dropwise, the mixture was cooled to room temperature. The upper layer of liquid was poured out and the precipitate was washed with water. A sufficient amount of ether was then added, the solution was separated into layers, and the lower layer was separated using a separatory funnel. The solution was evaporated to dryness at 60°C to obtain phosphotungstic acid solid.

[0034] Then prepare cesium phosphotungstate, the reaction equation is:

[0035] H3PW 12 O 40 +1.25Cs2CO3→Cs 2.5 H 0.5 PW 12 O 40 +1.25CO2+1.25H2O;

[0036] 1.25 parts by mass of Cs2CO3 and 9.175 parts by mass of pretreated phosphotungstic acid were prepared into 0.1 mol / L and 0.08 mol / L solutions respectively; at 60 ° C, 0.1 mol / L Cs2CO3 solution was added dropwise to 0.08 mol / L H3PW at a rate of 1 mL / min. 12 O 40 The solution was stirred continuously during the whole process; after the addition, stirring was continued for 30 minutes, and then the solution was allowed to stand at room temperature for 20 hours; then the water was slowly evaporated at 60 ° C, and white solid cesium phosphotungstate Cs was obtained after 48 hours. 2.5 H 0.5 PW 12 O 40 .

[0037] Step 102: synthesizing and isolating cucurbitacin CB from glyoxal and urea raw materials;

[0038] In step 102, urea and a 40% aqueous solution of glyoxal are refluxed at a certain temperature to obtain glycoluril through a condensation reaction. The specific operation method is as follows: first, a certain amount of urea solution is prepared, and its pH is adjusted to about 2 with hydrochloric acid, and the molar ratio of urea to glyoxal is controlled to be 2:1. Then, the temperature is raised to 70°C in a condensation reflux experimental device, and the 40% glyoxal solution is added dropwise to the urea solution at a rate of 1 ml per minute. After reacting for about 3 hours, the solution begins to separate. The white solid precipitate is collected, filtered, and the filtrate is repeatedly washed with a dilute NaOH solution and distilled water, and then dried in a vacuum drying oven. The method comprises the steps of: drying the mixture at 120°C for 3-5 hours to obtain a glycoluril monomer; dissolving the glycoluril in a certain amount of 3 mol / L hydrochloric acid, cooling the mixture to 0°C, then adding paraformaldehyde powder in a ratio of glycoluril to paraformaldehyde of 2:1, mixing the mixture thoroughly, shaking the mixture, and standing the mixture for 1 hour at room temperature after gel formation, and then heating the mixture to 90°C and maintaining the temperature for 4 hours; after the reaction is completed, cooling the mixture and standing the mixture, then filtering the mixture, adding a large amount of acetone to the filtrate to produce a white precipitate, and recovering and drying the mixture after separation to produce a solid crystalline precipitate. The dried white solid powder is cucurbitacin (CB).

[0039] Step 103: Obtain cesium phosphotungstate-cucurbitacin inclusion complex CsPW-CB by ultrasonic co-dissolution method.

[0040] In step 103, the amount of the substance Cs that is stored in a dry state is taken. 2.5 H 0.5 PW 12 O 40 Prepare 0.1 mol / L aqueous solution respectively; slowly drop the phosphotungstic acid aqueous solution into the cucurbitacin aqueous solution under ultrasonic vibration, and fully ultrasonically vibrate for 3 hours; then use a rotary evaporator to evaporate the solution water at 40 ° C to obtain a white powdery substance, namely cucurbitacin and Cs 2.5 H 0.5 PW 12 O 40 inclusion complex CsPW-CB.

[0041] Step 2: The waste cooking oil raw material is filtered to remove impurities and heated to 120-160°C for dehydration to complete the raw material pretreatment;

[0042] Step 3: Add waste cooking oil to a reactor and preheat the reactor to 70°C; then add a catalyst and methanol; the catalyst is added in an amount of 1.5wt%-2.5wt% of the waste cooking oil; the methanol-to-oil ratio is 10-12:1; simultaneously turn on a water condenser and a magnetic stirrer; after reacting for 140-160 minutes, transfer the solution to a centrifuge to separate the catalyst, transfer the filtrate to a container and let it stand for 24 hours to allow most of the methanol to evaporate; after sufficient standing, the filtrate separates into two layers: a lower layer of glycerol and an upper layer of biodiesel;

[0043] Step 4: Separate the upper layer of biodiesel; use distilled water to wash away a small amount of methanol, saponification and glycerol in the biodiesel; use a rotary evaporator to remove water and methanol in the biodiesel to obtain pure biodiesel.

[0044] In the actual experimental process of the present invention, a total of 29 groups of experimental conditions were carried out through the mathematical model and according to the design of the software. The software gave random experiments, and the experimental results are shown in Table 1. It can be seen from Table 1 that the conversion rate and the predicted conversion rate are on the far right. Through data comparison, the largest difference occurred in the 5th group of experiments, reaching 3.3%; the difference in the 10th group reached 3.1%; the difference in the 14th group was 0%; most of the differences were still within 3%, indicating that the model is reliable and can better reflect the actual situation of the experiment.

[0045]

[0046]

[0047] Table 1

[0048] In the present invention, CsPW-CB has a good and efficient catalytic effect in experiments for catalyzing the transesterification reaction of waste cooking oil to prepare biodiesel. Through two experimental methods, single factor and response surface optimization, a maximum conversion rate of 95.1% was obtained from the 29th group of experiments. At this time, the reaction conditions are: catalyst dosage of 2wt%, alcohol-to-oil ratio of 11:1, reaction time of 150 minutes, and temperature of 70°C. Compared with the existing technology, the present invention can synthesize a low-cost catalyst, shorten production time, reduce production costs, and improve production efficiency.

[0049] In the present invention, a gas chromatography-mass spectrometer, a vortex mixer, and a TTL-DC hydrogen blowdown analyzer are used to analyze samples. 1 mL of a biodiesel sample is taken, and the reaction conditions are: a catalyst dosage of 2 wt%, an alcohol-to-oil ratio of 11:1, a reaction time of 150 minutes, and a temperature of 70°C; 9 mL of n-hexane is added to dilute the sample and mixed in a vortex mixer. 1 mL of the dilution is then taken into a graduated test tube, blown dry with a nitrogen blowdown analyzer, and then redissolved in 1 mL of n-hexane for sample analysis. Figure 1The main components of vegetable oil and biodiesel obtained from the gas chromatogram shown in Table 2 are listed in Table 2. The names and molecular formulas of the components are listed in Table 2.

[0050]

[0051] Table 2: Main components of biodiesel

[0052] By calculating the peak areas and their ratios in the gas chromatogram, the composition of the biodiesel was determined. The fatty acid methyl esters (FAMs) content reached 96.8%. The main products were cis-octadecanoic acid methyl ester (45.05%), erucic acid methyl ester (28.79%), trans-oleic acid methyl ester (6.38%), palmitic acid methyl ester (5.16%), and stearic acid methyl ester (4.93%). The large amount of FAMEs detected indicates that the waste cooking oil was essentially completely converted.

[0053] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained herein shall, unless otherwise specified or limited, be implemented in accordance with conventional means in the art.

Claims

1. A method for extracting industrial fuel from waste cooking oil, characterized in that: The following steps are involved: Step 1: preparing a cesium phosphotungstate-cucurbitacin inclusion complex catalyst; Step 2: The waste cooking oil raw material is filtered to remove impurities and heated to 120-160°C for dehydration to complete the raw material pretreatment; Step 3: Add waste cooking oil to a reactor and preheat the reactor to 70°C; then add a catalyst and methanol; the catalyst is added in an amount of 1.5wt%-2.5wt% of the waste cooking oil; the methanol-to-oil ratio is 10-12:1; simultaneously turn on a water condenser and a magnetic stirrer; after reacting for 140-160 minutes, transfer the solution to a centrifuge to separate the catalyst, transfer the filtrate to a container and let it stand for 24 hours to allow most of the methanol to evaporate; after sufficient standing, the filtrate separates into two layers: a lower layer of glycerol and an upper layer of biodiesel; Step 4: Separate the upper layer of biodiesel; use distilled water to wash away a small amount of methanol, saponification and glycerol in the biodiesel; use a rotary evaporator to remove water and methanol in the biodiesel to obtain pure biodiesel.

2. The method for extracting industrial fuel from waste cooking oil according to claim 1, wherein: In the step 1, the preparation of the cesium phosphotungstate-cucurbitacin inclusion complex catalyst comprises the following steps: Step 101: Prepare cesium phosphotungstate Cs using sodium phosphotungstate, concentrated hydrochloric acid and cesium carbonate as raw materials. 2.5 H 0.5 PW 12 O 40 ; Step 102: synthesizing and isolating cucurbitacin CB from glyoxal and urea raw materials; Step 103: Obtain cesium phosphotungstate-cucurbitacin inclusion complex CsPW-CB by ultrasonic co-dissolution method.

3. The method for extracting industrial fuel from waste cooking oil according to claim 1, wherein: In step 101, phosphotungstic acid is first prepared, and the ionic formula is: Under magnetic stirring, add 50 parts by mass of Na2WO·2H2O and 8.5 parts by mass of dipotassium hydrogen phosphate to 100 mL of boiling water and continue stirring. After dissolution, add 50-60 parts by mass of concentrated hydrochloric acid dropwise. The density of concentrated hydrochloric acid is 1.18 g / ml. After the addition of hydrochloric acid, white crystals of phosphotungstic acid begin to precipitate. After the hydrochloric acid is added dropwise, the mixture is cooled to room temperature; the upper liquid is poured out and the precipitate is washed with water; sufficient ether is then added, the solution is separated into layers, and the lower layer is separated using a separatory funnel; the solution is evaporated to dryness at 60°C to obtain phosphotungstic acid solid; Then prepare cesium phosphotungstate, the reaction equation is: H3PW 12 O 40 +1.25Cs2CO3→Cs 2.5 H 0.5 PW 12 O 40 +1.25CO2+1.25H2O; 1.25 parts by mass of Cs2CO3 and 9.175 parts by mass of pretreated phosphotungstic acid were prepared into 0.1 mol / L and 0.08 mol / L solutions respectively; at 60 ° C, 0.1 mol / L Cs2CO3 solution was added dropwise to 0.08 mol / L H3PW at a rate of 1 mL / min. 12 O 40 The solution was stirred continuously during the whole process; after the addition, stirring was continued for 30 minutes, and then the solution was allowed to stand at room temperature for 20 hours; then the water was slowly evaporated at 60 ° C, and white solid cesium phosphotungstate Cs was obtained after 48 hours. 2.5 H 0.5 PW 12 O 40 .

4. The method for extracting industrial fuel from waste cooking oil according to claim 1, wherein: In step 102, urea and a 40% aqueous solution of glyoxal are refluxed at a certain temperature to obtain glycoluril through a condensation reaction. The specific operation method is as follows: first, a certain amount of urea solution is prepared, and its pH is adjusted to about 2 with hydrochloric acid, and the molar ratio of urea to glyoxal is controlled to be 2:

1. Then, the temperature is raised to 70°C in a condensation reflux experimental device, and the 40% glyoxal solution is added dropwise to the urea solution at a rate of 1 ml per minute. After about 3 hours of reaction, the solution begins to separate; the white solid precipitate is collected, filtered, and the filtrate is repeatedly washed with a dilute NaOH solution and distilled water in sequence, and dried in a vacuum drying oven at 120°C for 3-5 hours to obtain glycoluril monomer; glycoluril is dissolved in a certain amount of 3 mol / L hydrochloric acid, cooled to 0°C, and then paraformaldehyde powder is added at a ratio of glycoluril to paraformaldehyde of 2:

1. The mixture is thoroughly mixed and shaken, and then allowed to stand. After a gel appears, the mixture is placed at room temperature for 1 hour, and then heated to 90°C and maintained at this temperature for 4 hours. After the reaction is completed, the obtained The mixture was cooled and allowed to stand, then filtered, and a large amount of acetone was added to the filtrate to produce a white precipitate. After the solid crystalline precipitate appeared after separation, it was recovered and dried. The white solid powder obtained by drying was Cucurbitacin (CB).

5. The method for extracting industrial fuel from waste cooking oil according to claim 1, wherein: In step 103, take the amount of CB and Cs that are stored dry. 2.5 H 0.5 PW 12 O 40 Prepare 0.1 mol / L aqueous solution respectively; slowly drop the phosphotungstic acid aqueous solution into the cucurbitacin aqueous solution under ultrasonic vibration, and fully ultrasonically vibrate for 3 hours; then use a rotary evaporator to evaporate the solution water at 40 ° C to obtain a white powdery substance, namely cucurbitacin and Cs 2.5 H 0.5 PW 12 O 40 inclusion complex CsPW-CB.

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