A kind of preparation method of biofuel
Technical field
The present invention relates to a kind of by grease and monohydroxy-alcohol prepared in reaction method of bio-diesel oil.
Background technology
Biofuel can be that triglyceride level and low-carbon alcohol are carried out transesterification reaction and made through grease; Fatty ester and mono-glycerides, two sweet esters, glycerine, pure and mild unreacted triglyceride level are arranged in the reaction product; Can obtain biofuel through separating; Wherein mainly be fatty ester, also contain a spot of mono-glycerides and two sweet esters.
The preparation method of biofuel can be divided into acid catalyzed process, base catalysis method, enzyme catalysis method and supercritical methanol technology.
CN1412278A discloses a kind of acid catalyzed process, with the method for preparing biological diesel oil from high acid value waste animal and plant oil, it with sulfuric acid as catalyzer; Operation according to raw material dehydration, esterification and transesterify, phase-splitting, decolouring is carried out, and raw material dewaters under the vacuum earlier at 60-100 ℃; Then, under 40~85 ℃, sulfuric acid add-on 2~6%; Carried out esterification and transesterification reaction 6 hours, and told the fatty acid methyl ester phase, with atlapulgite 90~125 ℃ of decolourings get final product biofuel.
It is raw material that CN1473907A adopts the tankage of vegetable oil refining and the edible oil of recovery; Catalyzer is inorganic and organic acid is composite forms by sulfuric acid, hydrochloric acid, tosic acid, Witco 1298 Soft Acid, naphthene sulfonic acid etc.; Produce through operations such as acidifying removal of impurities, continous vacuum dehydration, esterification, layering, underpressure distillation; Esterif iotacation step catalyzer add-on 1~3%, 60~80 ℃ of esterification temperatures, 6 hours reaction times.Reaction product neutralization is earlier removed catalyzer, and then, layering removes and anhydrates, and the after product that anhydrates obtains biofuel through underpressure distillation.
The acid catalysis existing problems are that speed of response is slow, have a large amount of spent acid, waste water generation in addition.
The speed of response of base catalysis method is faster than acid catalyzed process; If but free fatty acid content is more in the grease; Directly use alkaline catalysts can produce fatty acid soaps, alkaline catalysts must be excessive in this case, can cause the fatty ester layer to separate with glycerin layer like this and become difficulty.For avoiding these problems, DE3444893 discloses a kind of method, at first; Oil plant is carried out preparatory esterification treatment; With acid catalyst, normal pressure, 50~120 ℃, free fatty acids and alcohol are carried out esterification, add then in the excessive base metal catalysts and the residual acid catalyst of esterification in advance; Carry out transesterification reaction again, the requirement of base metal catalysts has bigger increase.Adopt that the pre-esterifying process existing problems are that technical process is long, step is many, facility investment, energy consumption significantly rise, and in addition, needs from reaction process and product, remove acid, basic catalyst, needs with a large amount of washing water the generation great amount of wastewater.
US5713965A discloses a kind of method, in the presence of lypase, makes solvent with hexane, through grease and pure prepared in reaction fatty acid methyl ester.Though adopt the enzyme catalyst reaction conditions to relax, long reaction time, efficient are lower, need solvent, and enzyme are more expensive, in high purity methanol, are prone to inactivation.
PCT/JP99/0543 discloses the method for a kind of grease and monohydroxy-alcohol prepared in reaction fatty ester, at 270~280 ℃, under 11~12MPa, methyl alcohol is reacted with oil plant, and the fatty acid methyl ester yield is 55~60%.This method severe reaction conditions is high to equipment requirements.
Summary of the invention
It is a kind of under than the demulcent condition that the present invention provides, and need not the high yield of catalyzer and prepare method of bio-diesel oil, and not only reaction conversion ratio is near 100w%, and the biofuel yield is high.
The preparation method of biofuel provided by the invention comprises: with grease and alcohol reactor drum is provided, carries out transesterification reaction, separate and collection of biological diesel oil and glycerine.
Said grease is a fatty acid triglycercide; Be mainly derived from animal oil or vegetables oil; Comprise also that in addition acid value of oil and fat can change in the larger context, for example 1~190mgKOH/g from the oil plant in the materials such as mikrobe, algae; Preferred 20~160mgKOH/g, more preferably 30~130mgKOH/g.High-acid value grease in above-mentioned acid number scope can be crude oil, waste grease or rotten grease etc.Wherein crude oil is meant without the grease that does not reach product standard after refining or refining, the refining step operations such as matter, alkali refining, dephosphorization matter, decolouring, deodorization that include but not limited to come unstuck.High-acid value grease in above-mentioned acid number scope also can obtain through extra adding free fatty acids in grease.
Said monohydroxy-alcohol is meant that carbon number is 1~6 Fatty Alcohol(C12-C14 and C12-C18), can be single Fatty Alcohol(C12-C14 and C12-C18), also can be the mixture of one or more Fatty Alcohol(C12-C14 and C12-C18), particular methanol and ethanol.
Said reactor drum is fixed-bed reactor, preferred tubular reactor.Grease and alcohol can offer reactor drum separately, or with offering reactor drum after their pre-mixings, before offering reactor drum; Available preheater also can directly get into reactor drum, like this with the material preheating; Reactor drum had both played the effect of preheater, also played the effect of reactor drum.As adopt preheater, preheating together after can or mixing grease and alcohol difference preheating.
100~260 ℃ of temperature of reactor, preferred 140~235 ℃, more preferably 170~220 ℃; Pressure 0.2~7MPa, preferred 1~6MPa, more preferably 2~5MPa; Oil/pure mass ratio is 0.4~8:1, is preferably 1~7:1, more preferably 2~7:1.Liquid hourly space velocity is 0.1~5h
-1, preferred 0.3~2h
-1
For the reacting coarse product that obtains, can steam monohydroxy-alcohol through flash distillation; From the mixture behind the flash distillation monohydroxy-alcohol, separate then mixed ester mutually with glycerine mutually, can separate the separation of optimum fiber bundle through settlement separate or fibrous bundle separator; Separation condition is 20~150 ℃ of temperature; Preferred 40~100 ℃, pressure greater than a normal atmosphere or normal pressure all can, air speed 0.1-10h
-1, preferred 1~4h
-1Then mixed methyl phase and glycerine are distilled respectively; Can be through rectification under vacuum tower or thin-film evaporator distillation, pressure is less than 0.1MPa, preferably less than 0.04MPa; Reflux ratio 0.1~10:1 in the rectifying tower; Preferred 1~6:1, tower still or thin film evaporation actuator temperature are 100~300 ℃, preferably less than 280 ℃.
According to method provided by the invention, product yield can reach more than the 80w%.Technology of the present invention is particularly suitable for processing the higher non-refining oil of acid number, can save the numerous and diverse preprocessing process of operation, and energy consumption, facility investment are descended.The basic three-waste free discharge of this technology is an eco-friendly friendly process.
Embodiment
Further specify the present invention through instance below, but the present invention is not limited to this.
Relevant nominal definition is following among the embodiment:
Yield=(biofuel weight/grease weight) * 100%
The oil quantity that liquid hourly space velocity=unit volume reactor drum unit time handles
W% representes weight percentage.
Embodiment 1
Grease and the methyl alcohol of acid number 104.7mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 160 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor, 200~205 ℃ of temperature of reaction, and pressure 2.0~2.5MPa, reacting coarse product gets into flashing tower,<remove methyl alcohol for 150 ℃, and methyl alcohol is reclaimed, reuses, leftover materials are got into the fibrous bundle separator, at 20 ℃ of temperature, liquid hourly space velocity 5h
-1, tell the mixed ester phase, the middle mutually content of triglyceride 2.4w% of mixed ester, mixed ester gets into thin-film evaporator mutually, at pressure 6mmHg, under the condition that temperature is 240 ℃, steams biofuel, yield 85.2w%.
Embodiment 2
Grease and the methyl alcohol of acid number 58.1mgKOH/g are provided in the preheater liquid hourly space velocity 0.7h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 160 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor, 220 ℃ of temperature of reaction, and pressure 5.5~6.0MPa, the crude product of outflow reactor gets into flashing tower,<remove methyl alcohol and methyl alcohol is reclaimed, reuses for 150 ℃.Leftover materials are got into the fibrous bundle separator, at 30 ℃ of temperature, liquid hourly space velocity 10h
-1Under the condition, tell continuously mixed ester mutually with glycerine mutually, the middle mutually content of triglyceride 0 of ester, mixed ester gets into the rectification under vacuum tower mutually, at pressure 11mmHg, 267 ℃ of tower stills under the condition of reflux ratio 3:1, steam biofuel, yield 93w%.
Embodiment 3
Grease and the methyl alcohol of acid number 49.3mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 110 Grams Per Hours respectively
-1, 140 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor, 200~205 ℃ of temperature of reaction, and pressure 3.5~4MPa, the reacting coarse product of outflow reactor gets into flashing tower,<remove methyl alcohol and methyl alcohol is reclaimed, reuses for 150 ℃, leftover materials are got into the fibrous bundle separator, at 60 ℃ of temperature, liquid hourly space velocity 5h
-1, divide the ester output phase, the middle mutually content of triglyceride 1.25w% of ester, ester gets into the rectification under vacuum tower mutually, and at pressure 15mmHg, 279 ℃ of tower stills under the condition of reflux ratio 0.6:1, steam biofuel, and yield can reach 88.2w%.
Embodiment 4
Grease and the methyl alcohol of acid number 35.3mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 128 Grams Per Hours respectively
-1, 140 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor, and temperature of reaction 225-230 ℃, pressure 0.7~0.9MPa, the crude product of outflow reactor gets into flashing tower,<remove methyl alcohol and methyl alcohol is reclaimed, reuses for 150 ℃, leftover materials carry out settlement separate, divide ester output mutually with glycerine mutually; Mixed ester gets into thin-film evaporator mutually, at pressure 11mmHg, under the condition that temperature is 255 ℃; Steam biofuel, yield 74.4w%.
Embodiment 5
Grease and the methyl alcohol of acid number 125.7mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 170 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor; 200~205 ℃ of temperature of reaction, pressure 3.5~4MPa, the crude product of outflow reactor separates by the method for embodiment 3; Obtain biofuel, yield 71.4w%.
Embodiment 6
Grease and the methyl alcohol of acid number 81.2mgKOH/g are provided in the preheater liquid hourly space velocity 0.7h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 140 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor, 180 ℃ of temperature of reaction, and pressure 5.8~6.0MPa, the crude product of outflow reactor separates by the method for embodiment 2, steams biofuel, yield 90.7w%.
Embodiment 7
Grease and the methyl alcohol of acid number 22.5mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 170 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor; 210~215 ℃ of temperature of reaction, pressure 2.0~2.5MPa, the crude product of outflow reactor separates by the method for embodiment 4; Steam biofuel, yield 51.2w%.
Comparative example 1
Grease and the methyl alcohol of acid number 0.4mgKOH/g are provided in the preheater liquid hourly space velocity 0.6h with the speed of 600 Grams Per Hours and 100 Grams Per Hours respectively
-1, 170 ℃ of preheater temperature continuously are provided to the material after the preheating in the tubular reactor; 210~215 ℃ of temperature of reaction, pressure 2.0~2.5MPa, the crude product of outflow reactor separates by the method for embodiment 1; Steam biofuel, yield 19.7w%.