A method for preparing biomass liquid fuel from waste

Abstract

The present invention relates to a method for preparing biomass liquid fuel from waste materials, and the method is as follows: After sorting kitchen waste, oil-containing agricultural and forestry waste, and industrial waste oil, performing thermal flash evaporation, solid-liquid separation, and then sterilization treatment to mix them into a waste water-oil mixture, subcritical alcohol reacts with the waste water-oil mixture in a subcritical transesterification reaction. Subcritical oil products are separated in a first separation tower with isothermal pressure reduction. The subcritical oil products react with supercritical alcohol in a supercritical transesterification reaction, and supercritical oil products are separated in a second separation tower with isobaric temperature reduction. After decolorization treatment, the finished biomass liquid fuel is obtained. Using the waste water-oil mixture treated with low-cost waste materials, without a catalyst, through the combination of subcritical transesterification and supercritical transesterification, hierarchical separation, the difficulty of controlling the continuous treatment process conditions is reduced, the process steps are simplified, the cetane number, reaction efficiency, extraction efficiency, and yield are improved, the acid value in the oil products is reduced, the atomization performance and storage stability are improved, and it meets the requirements for combustion use.

Description

Technical Field

[0001] The present invention relates to a method for preparing biomass liquid fuel from waste, and belongs to the technical field of biomass liquid fuel production equipment. Background Art

[0002] Biomass liquid fuel is the terminal energy converted from biomass energy resources. Compared with fossil fuels, the combustion of biofuel can effectively reduce atmospheric pollutants such as NO x and SO x etc. Moreover, due to the presence of intramolecular oxygen and good self-lubrication, it provides support for the full combustion of diesel-powered vehicles. Its flash point is higher than that of petrochemical diesel, and it does not belong to dangerous fuel. It has obvious advantages in transportation, storage, use, etc., which is conducive to changing the fuel structure, reducing energy resource consumption and dependence on petrochemical fuels, maintaining the environmental ecology, and saving environmental protection costs. In the prior art, methods such as physical direct mixing, high-temperature pyrolysis, transesterification, and biocatalytic enzyme can be used to produce biomass liquid fuel. Among them, the transesterification reaction of oil and short-chain alcohol is relatively common, but its catalytic activity is greatly affected by the acidity and alkalinity of the raw materials. At the same time, the subsequent impurity removal and recovery processes of the acid catalyst or base catalyst contained are complex, the dissociation process is slow, and the conversion rate is difficult to meet the requirements.

[0003] Since the production of biomass liquid fuel in the prior art mainly uses agricultural products such as soybeans and rapeseeds as raw materials, the cost fluctuates greatly due to the limitation of raw material production. The carbon chain containing triglyceride is longer and the viscosity is higher than that of traditional diesel, the fluidity is poor, and it is not easy to gasify in the combustion chamber. A certain water content reduces the calorific value of the oil, the cetane number is not high, the acid value is high, and it is easy to deteriorate, which limits the blending amount and finished product application of biomass liquid fuel. There are problems of coking, carbon deposition and lubricating oil pollution to varying degrees when applied to engines, and it is difficult to meet the long-term application requirements. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art and provide a method for preparing biomass liquid fuel from waste. It uses the wastewater-oil mixture treated with low-cost waste raw materials, without the need for a catalyst, combines subcritical transesterification and supercritical transesterification, performs fractional separation, reduces the difficulty of controlling the continuous treatment process conditions, simplifies the process steps, improves the cetane number, reaction efficiency, extraction efficiency and yield, reduces the acid value in the oil product, improves the atomization performance and storage stability, and meets the combustion use requirements.

[0005] The present invention is realized by the following technical solutions:

[0006] A method for preparing biomass liquid fuel from waste, the method is as follows:

[0007] S1: Sort kitchen waste, oil-containing agricultural and forestry waste, and industrial waste oil, remove large solid particles, and put them into a separation tower under anaerobic conditions for thermal flash evaporation. The thermal flash evaporation temperature is 110 - 180 °C, and the time is 20 - 30 min. After the bottom material of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation, the separated liquid is taken and mixed with the top condensate after sterilization and cooling to form a waste oil mixture;

[0008] S2: Place the waste oil mixture in a preheated subcritical reactor, pressurize and feed subcritical alcohol into the subcritical reactor, and carry out subcritical transesterification reaction under anaerobic, low-temperature and high-pressure conditions. The top material is sent to an isothermal depressurization primary separation tower to separate the bottom subcritical oil product and the top subcritical alcohol. The top subcritical alcohol is sent to a storage tank for collection and used for pressurized circulation reaction;

[0009] The subcritical alcohol is one or more of methanol, ethanol, and 1-propanol. The mass ratio of the waste oil mixture to the subcritical alcohol is (1 - 3):10. The temperature of the subcritical reactor is 150 - 180 °C, and the pressure is 6 - 8 Mpa. The pressure in the primary separator is 3 - 5 Mpa;

[0010] S3: Place the bottom subcritical oil product in step S2 in a preheated supercritical reactor, pressurize and feed supercritical alcohol into the supercritical reactor, and carry out supercritical transesterification reaction under anaerobic, high-temperature and high-pressure conditions. The top material is sent to an isobaric cooling secondary separation tower to separate the bottom supercritical oil product and the top supercritical alcohol. The top supercritical alcohol is sent to a storage tank for collection and used for pressurized circulation reaction;

[0011] The supercritical alcohol is one or two of benzyl alcohol and β-phenylethyl alcohol. The mass ratio of the bottom subcritical oil product to the supercritical alcohol is (1 - 2):8. The temperature of the subcritical reactor is 240 - 280 °C, and the pressure is 3 - 5 Mpa. The temperature in the secondary separator is 120 - 150 °C;

[0012] S4: Place the bottom supercritical oil product in step S3 and the decolorizing agent in a decolorizing tower for decolorization treatment. The liquid obtained by centrifugal solid-liquid separation, or the stirred blend of the liquid with industrial oil and chemical additives is used as the finished product of biomass liquid fuel.

[0013] In the above method for preparing biomass liquid fuel from waste, the mass ratio of the bottom supercritical oil product to the decolorizing agent in step S4 is 100:(4 - 8). The decolorization temperature is 40 - 80 °C, and the stirring rate during decolorization is 100 - 150 r / min. The decolorizing agent is attapulgite clay or activated clay;

[0014] The above method for preparing biomass liquid fuel from waste, wherein the industrial oil is one or more of No. 36 white oil, No. 26 white oil, No. 32 engine oil or naphthenic oil XJ-HWY1; the chemical additive is dibutyl phosphite T304 or zinc butyl octyl thiophosphate T202; the mixing mass ratio of the liquid to the industrial oil and the chemical additive is: 50:(10 - 30):(0.6 - 0.8).

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) Through the thermal flash evaporation treatment of waste under anaerobic conditions, light waste oil and water are separated, heavy waste oil is separated from solid and liquid, fibrous substances are removed, and after sterilization to reduce the influence of cells, a subcritical transesterification reaction is carried out under anaerobic, low-temperature and high-pressure conditions, solving the phase solubility problem of the alcohol-oil two-phase. Without the need for a catalyst, the water in the wastewater-oil mixture will not only cause hydrolysis or saponification reaction of the catalyst to consume the catalyst and increase gel formation, making separation and recovery difficult, but also acts as an acidic catalyst, improving the hydrophilicity and hydrophobicity of alcohols, undergoing subcritical transesterification reaction and free fatty acid and methyl esterification reaction, and rapid separation by isothermal pressure reduction;

[0017] (2) Under the action of high temperature and high pressure and in an anaerobic supercritical state, aromatic supercritical alcohols react with the oils and fats in the subcritical oil products at the bottom of the tower to undergo supercritical transesterification reaction and free fatty acid and aromatic esterification reaction, generating methyl aromatic acid, monoester or aldehyde substances. By isobaric cooling, the combination of supercritical and subcritical reduces the control difficulty of the continuous treatment process conditions, improves the cetane number, reaction efficiency, extraction efficiency and yield, and reduces the acid value of the oil products;

[0018] (3) Through decolorization treatment, pigments, trace metals, odors, sulfides, peroxides in the oil products are removed, the viscosity is reduced, and it can be blended with industrial oils and chemical additives to improve antioxidant, anti-corrosion, wear-resistant properties and blending and dispersion properties, thereby improving the volatility, atomization performance and storage stability, meeting the usage requirements of various machinery, significantly reducing costs, having high economic cost performance, and being beneficial to environmental protection and energy sustainable development. Description of the Drawings

[0019] Figure 1 It is the process flow chart of the present invention. Detailed Embodiments

[0020] The following further describes the detailed embodiments of the present invention with reference to the drawings and examples.

[0021] Example 1:

[0022] A method for preparing biomass liquid fuel from waste, the method is as follows:

[0023] S1: Sort 50 kg of kitchen waste, 1 kg of decomposed residue of oil-containing agricultural and forestry waste, and 12 kg of industrial waste oil, remove large solid particles, and put them into a separation tower under anaerobic conditions for thermal flash evaporation. The thermal flash evaporation temperature is 152 °C and the time is 25 min. After the bottom material of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation, the separated liquid is taken and mixed with the top condensate after sterilization and cooling to form a waste oil mixture;

[0024] S2: Place the waste oil mixture in a preheated subcritical reactor, send subcritical alcohol under pressure into the subcritical reactor, and carry out subcritical transesterification reaction under anaerobic, low-temperature and high-pressure conditions. The top material is sent into an isothermal depressurized first separation tower to separate the bottom subcritical oil product and the top subcritical alcohol. The top subcritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0025] The subcritical alcohol is composed of methanol and 1-propanol in a mass ratio of 1:1. The mass ratio of the waste oil mixture to the subcritical alcohol is 2:10. The temperature of the subcritical reactor is 160 °C and the pressure is 7 Mpa. The pressure in the first separator is 4 Mpa;

[0026] S3: Place the bottom subcritical oil product in step S2 in a preheated supercritical reactor, send supercritical alcohol under pressure into the supercritical reactor, and carry out supercritical transesterification reaction under anaerobic, high-temperature and high-pressure conditions. The top material is sent into an isobaric cooling second separation tower to separate the bottom supercritical oil product and the top supercritical alcohol. The top supercritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0027] The supercritical alcohol is benzyl alcohol. The mass ratio of the bottom subcritical oil product to the supercritical alcohol is 2:8. The temperature of the subcritical reactor is 270 °C and the pressure is 4 Mpa. The temperature in the second separator is 130 °C;

[0028] S4: Place the bottom supercritical oil product in step S3 and a decolorizing agent in a decolorizing tower for decolorization treatment. The mass ratio of the bottom supercritical oil product to the decolorizing agent is 100:6. The decolorization temperature is 75 °C and the stirring rate during decolorization is 120 r / min. The decolorizing agent is attapulgite clay;

[0029] The liquid obtained by centrifugal solid-liquid separation and the stirring blend of industrial oil and chemical additives are used as the finished product of biomass liquid fuel. The industrial oil is naphthenic oil XJ-HWY1; the chemical additive is dibutyl phosphite T304. The mixing mass ratio of the liquid, industrial oil and chemical additive is: 50:12:0.7.

[0030] Example 2:

[0031] A method for preparing biomass liquid fuel based on waste, the method is as follows:

[0032] S1: Sort 25 kg of kitchen waste, 3 kg of rotted residue of oil-containing agricultural and forestry waste, and 6 kg of industrial waste oil, remove large solid particles, and put them into a separation tower under anaerobic conditions for thermal flash evaporation. The thermal flash evaporation temperature is 175 °C and the time is 20 - 30 min. After the bottom material of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation, the separated liquid is taken and mixed with the top condensate after sterilization and cooling to form a waste oil mixture;

[0033] S2: Place the waste oil mixture in a preheated subcritical reactor, pressurize and send subcritical alcohol into the subcritical reactor, and carry out subcritical transesterification reaction under anaerobic, low-temperature and high-pressure conditions. The top material is sent into an isothermal depressurizing first separation tower to separate the bottom subcritical oil product and the top subcritical alcohol. The top subcritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0034] The subcritical alcohol is 1-propanol, and the mass ratio of the waste oil mixture to the subcritical alcohol is 2:10. The temperature of the subcritical reactor is 165 °C and the pressure is 7 Mpa. The pressure in the first separator is 3.5 Mpa;

[0035] S3: Place the bottom subcritical oil product in step S2 in a preheated supercritical reactor, pressurize and send supercritical alcohol into the supercritical reactor, and carry out supercritical transesterification reaction under anaerobic, high-temperature and high-pressure conditions. The top material is sent into an isobaric cooling second separation tower to separate the bottom supercritical oil product and the top supercritical alcohol. The top supercritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0036] The supercritical alcohol is β-phenethyl alcohol, and the mass ratio of the bottom subcritical oil product to the supercritical alcohol is 1.4:8. The temperature of the subcritical reactor is 260 °C and the pressure is 3.8 Mpa. The temperature in the second separator is 130 °C;

[0037] S4: Place the bottom supercritical oil product in step S3 and a decolorizing agent in a decolorizing tower for decolorization treatment. The mass ratio of the bottom supercritical oil product to the decolorizing agent is 100:6. The decolorization temperature is 50 °C and the stirring rate during decolorization is 120 r / min. The decolorizing agent is activated clay;

[0038] The liquid separated by centrifugal solid-liquid separation, or the stir-blended mixture of the liquid with industrial oil and chemical additives is used as the finished product of biomass liquid fuel. The industrial oil is composed of white oil No. 26 and machine oil No. 32 in a mass ratio of 10:1; the chemical additive is zinc dialkyldithiophosphate T202; the mixing mass ratio of the liquid, industrial oil and chemical additive is: 50:22:0.6.

[0039] Example 3:

[0040] A method for preparing biomass liquid fuel based on waste, and the method is as follows:

[0041] S1: Sort 15 kg of kitchen waste, 10 kg of decomposed residue of oil-containing agricultural and forestry waste, and 30 kg of industrial waste oil, remove large solid particles, and put them into a separation tower under anaerobic conditions for thermal flash evaporation. The thermal flash evaporation temperature is 170 °C and the time is 30 min. After the bottom material of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation, take the separated liquid and the top condensate, and after sterilization treatment and cooling, mix them into a waste oil mixture;

[0042] S2: Place the waste oil mixture in a preheated subcritical reactor, pressurize and send subcritical alcohol into the subcritical reactor, and carry out subcritical transesterification reaction under anaerobic, low-temperature and high-pressure conditions. The top material is sent into an isothermal depressurized first-stage separation tower to separate the bottom subcritical oil product and the top subcritical alcohol. The top subcritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0043] The subcritical alcohol is methanol, and the mass ratio of the waste oil mixture to the subcritical alcohol is 1:10. The temperature of the subcritical reactor is 160 °C and the pressure is 8 Mpa. The pressure in the first-stage separator is 4 Mpa;

[0044] S3: Place the bottom subcritical oil product in step S2 in a preheated supercritical reactor, pressurize and send supercritical alcohol into the supercritical reactor, and carry out supercritical transesterification reaction under anaerobic, high-temperature and high-pressure conditions. The top material is sent into an isobaric depressurized second-stage separation tower to separate the bottom supercritical oil product and the top supercritical alcohol. The top supercritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction;

[0045] The supercritical alcohol is β-phenethyl alcohol, and the mass ratio of the bottom subcritical oil product to the supercritical alcohol is 1.8:8. The temperature of the subcritical reactor is 260 °C and the pressure is 3.8 Mpa. The temperature in the second-stage separator is 130 °C;

[0046] S4: Place the bottom supercritical oil product in step S3 and the decolorizing agent in a decolorizing tower for decolorization treatment. The mass ratio of the bottom supercritical oil product to the decolorizing agent is 100:5. The decolorization temperature is 45 °C, and the stirring rate during decolorization is 120 r / min. The decolorizing agent is activated clay, and the liquid separated by centrifugal solid-liquid separation is used as the finished product of biomass liquid fuel.

[0047] Take Examples 1-3 and commercially available biodiesel (Jinan Jiaxu Chemical Industry) as the comparative example, and conduct performance tests according to the test standards in the table. The results are as follows:

[0048]

[0049]

[0050] The mechanism of the present invention is:

[0051] (1) As can be seen from the above table, the preparation method of the present invention is simple, and the materials are easily obtained. By using waste materials, kitchen waste, oil-containing agricultural and forestry waste, and industrial waste oil are sorted to prevent large solid particles from damaging the separation equipment. After thermal flash evaporation treatment under anaerobic conditions, light waste oil and water are separated, and the bottom product of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation to separate heavy waste oil, so as to fully remove impurities such as fibers and hemicellulose in the waste materials, and reduce the influence of microbial cells in the waste oil and water through mixed sterilization treatment;

[0052] (2) Using one or more of methanol, ethanol, and 1-propanol as subcritical alcohols solves the problem of phase solubility between alcohol and oil, avoids the problems of large solvent consumption, many impurities, and waste liquid discharge pollution during the reaction of traditional acid catalysts or base catalysts, and does not require a catalyst, so that the water in the waste water-oil mixture will not cause hydrolysis or saponification reaction of the catalyst to consume the catalyst, increase gel formation and make separation and recovery difficult, and makes the mixture more acidic to increase the reaction rate;

[0053] The subcritical transesterification reaction is carried out under anaerobic, low-temperature and high-pressure conditions. Rapid dissociation and weakened hydrogen bonding occur, and water acts as an acidic catalyst to improve the hydrophilicity and hydrophobicity of alcohols, and undergoes subcritical transesterification reaction with the oil in the waste water-oil mixture and free fatty acid and methyl esterification reaction to generate fatty acid methyl ester and monoester, and separation is carried out in an isothermal pressure-reducing primary separation tower. The partially subcritical alcohol at the bottom of the tower is recovered and recycled to reduce costs;

[0054] (3) Using one or two aromatic alcohols such as benzyl alcohol and β-phenylethyl alcohol under supercritical conditions, through high-temperature and high-pressure action, under anaerobic supercritical conditions, and undergoing supercritical transesterification reaction and free fatty acid and aromatic esterification reaction with the oil in the subcritical oil product at the bottom of the tower to generate methyl aromatic acid, monoester or aldehyde substances, and separation is carried out in an isobaric temperature-reducing secondary separation tower. The combination of supercritical and subcritical reduces the difficulty of controlling the continuous treatment process conditions;

[0055] The subcritical alcohol and supercritical alcohol are recovered and recycled to reduce costs, and through the temperature and pressure conditions of subcritical transesterification and supercritical transesterification, the energy consumption and control difficulty are reduced, the cetane number, reaction efficiency, extraction efficiency and yield are improved, the acid value in the oil product is reduced, and the phenomenon of deterioration or engine coking and carbon deposition during long-term use is avoided;

[0056] (4) Remove pigments, trace metals, odors, sulfides, and peroxides from the oil through decolorization treatment to reduce viscosity; white oil No. 36, white oil No. 26, engine oil No. 32, or naphthenic oil XJ-HWY1 is purchased from Zibo Xinjiu Co., Ltd., and dibutyl phosphite T304 or zinc dialkyldithiophosphate T202 is purchased from Nanjing Rongji. It can be blended with industrial oil bodies and chemical additives to improve antioxidant, corrosion resistance, wear resistance, and blending and dispersion properties, comprehensively utilize industrial non-refined oils, reduce viscosity, increase volatility, improve atomization performance and storage stability, meet the usage requirements of various machinery, significantly reduce costs, have high economic cost performance, and are beneficial to environmental protection and sustainable energy development.

[0057] As mentioned above, it is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for preparing biomass liquid fuel from waste, characterized in that, The method is as follows: S1: Sort kitchen waste, oil-containing agricultural and forestry waste, and industrial waste oil, remove large solid particles, and put them into a separation tower under anaerobic conditions for thermal flash evaporation. After the bottom material of the tower is subjected to pressing or vacuum centrifugal solid-liquid separation, the separated liquid and the top condensate are sterilized, cooled and mixed into a waste oil mixture; S2: Place the waste oil mixture in a preheated subcritical reactor, pressurize the subcritical alcohol and send it into the subcritical reactor, and carry out subcritical transesterification reaction under anaerobic, low-temperature and high-pressure conditions. The top material is sent into a first separation tower with isothermal pressure reduction to separate the bottom subcritical oil product and the top subcritical alcohol. The top subcritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction; S3: Place the bottom subcritical oil product in step S2 in a preheated supercritical reactor, pressurize the supercritical alcohol and send it into the supercritical reactor, and carry out supercritical transesterification reaction under anaerobic, high-temperature and high-pressure conditions. The top material is sent into a second separation tower with isobaric temperature reduction to separate the bottom supercritical oil product and the top supercritical alcohol. The top supercritical alcohol is sent into a storage tank for collection and used for pressurized circulation reaction; S4: Place the bottom supercritical oil product in step S3 and a decolorizing agent in a decolorizing tower for decolorization treatment. The liquid obtained by centrifugal solid-liquid separation, or the mixture of the liquid and industrial oil and chemical additives is used as the finished product of biomass liquid fuel.

2. The method for preparing biomass liquid fuel from waste according to claim 1, characterized in that, In step S1, the thermal flash evaporation temperature is 110-180 °C and the time is 20-30 min.

3. The method for preparing biomass liquid fuel from waste according to claim 1, characterized in that, In step S2, the subcritical alcohol is one or more of methanol, ethanol, and 1-propanol. The mass ratio of the waste oil mixture to the subcritical alcohol is (1-3):

10. The temperature of the subcritical reactor is 150-180 °C and the pressure is 6-8 Mpa. The pressure in the first separation tower is 3-5 Mpa.

4. The method for preparing biomass liquid fuel from waste according to claim 1, characterized in that, In step S3, the supercritical alcohol is one or two of benzyl alcohol and β-phenylethyl alcohol. The mass ratio of the bottom subcritical oil product to the supercritical alcohol is (1-2):

8. The temperature of the subcritical reactor is 240-280 °C and the pressure is 3-5 Mpa. The temperature in the second separation tower is 120-150 °C.

5. The method for preparing biomass liquid fuel from waste according to claim 1, characterized in that, In step S4, the mass ratio of the bottom supercritical oil product to the decolorizing agent is 100:(4-8). The decolorization temperature is 40-80 °C, and the stirring rate during decolorization is 100-150 r / min. The decolorizing agent is attapulgite clay or activated clay.

6. The method for preparing biomass liquid fuel from waste according to any one of claims 1 to 5, characterized in that, In step S4, the industrial oil is one or more of white oil No. 36, white oil No. 26, engine oil No. 32, or naphthenic oil XJ-HWY1.

7. The method for preparing biomass liquid fuel from waste according to claim 6, characterized in that, In step S4, the chemical additive is dibutyl phosphite T304 or zinc butyl thiophosphate T202.

8. The method for preparing biomass liquid fuel from waste according to claim 7, characterized in that, In step S4, the mixing mass ratio of the liquid, industrial oil, and chemical additive is: 50:(10-30):(0.6-0.8).

Images