CN102936606A - Method for preparing reducing monosaccharide from biomass hydrolysis - Google Patents

Abstract

The invention discloses a method for preparing reducing monosaccharide from biomass hydrolysis. The method comprises the main steps of putting lignocellulose biomass in a stirring reactor, hydrolyzing under a normal pressure or a pressure close to the normal pressure by using a dilute acid as a catalyst, wherein partial biomass raw material can be supplemented during the hydrolysis process; washing residues after the hydrolysis is finished; and performing enzyme hydrolysis in the same reactor, wherein a discharged acid solution can used for the enzyme hydrolysis of next batch of the raw materials after being neutralized; and the washing water can be used for washing the residues of acid hydrolysis of the next batch of the raw materials. With the method, pretreatment of the biomass can be carried out in a mild condition and performed with enzyme hydrolysis in the same reactor, thereby significantly reducing pretreatment cost.

Description

A kind of method that is prepared reductive monosaccharide by biomass by hydrolyzation

Technical field

The present invention relates to a kind of technology that is prepared reductive monosaccharide by biomass by hydrolyzation, specifically adopt in same reactor the cellulose biomass material series connection to carry out dilute acid hydrolysis and enzymic hydrolysis to prepare the technique of reductive monosaccharide.

Background technology

The energy and environmental problem just are being subject to increasing attention.Liquid fuel shortage in the long term will be the large problem of puzzlement human development.Under this background, biomass, as unique renewable resources that is converted into liquid fuel, come into one's own just day by day.Tellurian biomass resource is very abundant, estimate that its annual production is equivalent to ten times of the current required energy, but what be used as energy utilization is less than 1%, therefore the technology of biomass-making liquid fuel is rising, this is middle again with the easiest industrialization of lignocellulose-like biomass preparing fuel ethanol.

The method of lignocellulose-like biomass preparing alcohol is to be the cellulose hydrolysis in this raw material monose, then monose is fermented into to ethanol.But the cellulose macromolecule in this raw material can link together by a large amount of hydrogen bonds, form the fibrous bundle of crystalline structure.Such structure makes cellulosic character very stable, and it is water insoluble, also without reductibility.Be not hydrolyzed at normal temperatures, at high temperature hydrolysis is also very slow.Only, under catalyzer exists, cellulosic hydrolysis reaction could carry out significantly.Catalyzer commonly used is mineral acid and cellulase, has formed respectively thus acid hydrolysis and enzyme hydrolysis process.

Enzymic hydrolysis has many advantages.It carries out at normal temperatures, and the process energy consumption is low.Enzyme has very high selectivity, can generate single product, therefore the sugar yield obtained very high (being greater than 95%).Owing to substantially not adding pharmaceutical chemicals in enzymic hydrolysis, and only generate by product seldom, so purification process is relatively simple, also avoided pollution.

An important topic in the enzyme hydrolysis process exploitation is raw materials pretreatment.Due to the Mierocrystalline cellulose that forms biomass, between hemicellulose and xylogen, be wound around mutually, and there is crystalline structure in Mierocrystalline cellulose itself, can stop enzyme to approach cellulose surface, therefore efficiency is very low during the direct enzymic hydrolysis of biomass.Can remove delignification by pre-treatment, dissolve hemicellulose, or destroy cellulosic crystalline structure, thereby increase it, can approach surface, improve the hydrolysis productive rate.Good pretreatment technology should be able to meet the following conditions: (1) can promote sugared generation or be conducive to the enzymic hydrolysis of back; (2) can avoid the degraded loss of carbohydrate; (3) avoid generating to hydrolysis and harmful byproduct that ferments; (4) reasonable in economy.

Many pretreatment processs are studied, and dilute acid pretreatment is the pretreatment process be widely used at present, cost is low and efficiency is high, has good development prospect.Dilute acid pretreatment can success remove hemicellulose, be translated into wood sugar, be beneficial to follow-up cellulose hydrolysis.

So-called dilute acid pretreatment is carried out dilute acid hydrolysis to biomass material exactly.In the dilute acid hydrolysis process of cellulose series biomass, temperature of reaction and reaction times are two relevant parameters.When adopting higher temperature, can use the shorter reaction times; And, when adopting lower temperature, just must use the longer reaction times.

In tradition dilute acid pretreatment technique, acid hydrolysis and enzymic hydrolysis are carried out in different reactor, and in order to improve the utilization ratio of acid hydrolytic reaction device, the higher temperature of reaction of normal employing, therefore high pressure that will be more expensive by price or middle setting-out steam are as thermal source.Traditional dilute acid hydrolysis having relatively high expectations to equipment in addition.

Summary of the invention

The object of the invention is to propose a kind ofly can under the condition relaxed, by lignocellulose-like biomass, be prepared the method for reductive monosaccharide, solve traditional dilute acid hydrolysis pretreatment reaction condition harshness, the problem that high and acid hydrolysis and enzymic hydrolysis must be carried out in different reactor to equipment requirements.

Design of the present invention:

The contriver thinks, with respect to enzymic hydrolysis, often wants tens hours, and the required time of acid hydrolysis is wanted much shorter, even be also like this at relatively low temperature.Dilute acid pretreatment and enzymic hydrolysis are carried out in same reactor, can't obviously be reduced the utilization ratio of enzymatic hydrolysis reaction device.Owing to having omitted a solid discharging and a feeding-in solid body, total efficiency can obviously increase.Acid hydrolytic reaction carries out at relatively low temperature, just can be with more cheap low-pressure water steam as thermal source.Carry out owing to reacting at normal pressure or approaching under normal pressure, in hydrolytic process, can add the part biological raw material, to improve the sugared concentration in hydrolyzed solution, also lower to material and the manufacture requirement of reactor.In addition because enzymic hydrolysis need to be carried out (pH is in 5 left and right) under certain acidity, to the washing of acid hydrolysis solid residue also than being easier to.The inventor has proposed biomass acid in same reactor-enzyme series connection hydrolysis and has produced the technique of reductive monosaccharide for this reason.

Technique of the present invention comprises the steps:

(1) dilute acid hydrolysis:

To be placed in the reactor with whipping appts through the preliminary lignocellulose-like biomass raw material of pulverizing, and first pass into low-pressure steam and carry out preheating, then add a certain amount of dilute hydrochloric acid or dilution heat of sulfuric acid.Continue to pass into the low-pressure steam heating after liquid adds, start to stir simultaneously.After temperature reaches preset value (this value is at 90～110 ℃), be hydrolyzed 1～3 hour at this temperature, keep certain stir speed (S.S.) in reaction process.In hydrolysis, acid concentration used is 1～3%, and the mass ratio of acid solution and solid material is 6～10, and these two is has considered the numerical value after the vapor condensation.Can add the part biological raw material in hydrolytic process, its amount is 15～40% of raw material original bulk, according to the content of hemicellulose in raw material, determines.Can once add, also can divide several times and add.Can pass into a small amount of steam after adding to control temperature.

Washing and neutralization:

Stop after having reacted stirring, emit acid hydrolysis liquid, with a certain amount of liquid scrubbing acid hydrolysis solid residue, obtain washings 1.What said liquid was used when the processing of first raw material here is clear water, and what while criticizing afterwards the processing of raw material, use is the residue from enzymatic hydrolysis washing water that obtain during last consignment of time raw material is processed.

Sodium hydroxide or calcium hydroxide neutralization for acid solution to obtaining, obtain neutralizer.Can be used for the enzymic hydrolysis in the processing of next batch raw material.

The washings 1 obtained through the neutralization after as hydrolysis prods.

Enzymic hydrolysis:

Add a certain amount of liquid and a certain amount of cellulase in reactor, what said liquid was used when first raw material is processed here is clear water, and what while criticizing afterwards the processing of raw material, use is the neutralizer obtained during last consignment of time raw material is processed.The cellulase consumption is controlled at every 10～20 filter paper enzyme activities for the gram solid material.

Start after regulator solution pH=5 to stir, solid residue is carried out to enzymic hydrolysis.Controlling temperature in reaction process is 45～55 ℃.Hydrolysis is carried out after 12～48 hours stopping stirring, and emits enzyme hydrolyzate, with a certain amount of clear water detersive enzyme hydrolysis solid residue, and residue is pressed dry.Obtain washings 2.

The enzyme hydrolyzate obtained and through the neutralization washings 1 together with as hydrolysis prods.

Washings 2 can be used for the washing of the acid hydrolysis residue in the processing of next batch raw material.

Reactor used for being applicable to the stirring stirring reaction device of liquid-solid reaction in the present invention, want can anti-applicable acidity of the present invention and temperature range simultaneously, the carbon steel that material is lass lining or inner liner polytetrafluoroethylene.

Embodiment

Embodiment 1

Raw material and analytical procedure:

Raw materials used is bagasse, and it consists of: moisture 6.3%, hemicellulose 31.2%, Mierocrystalline cellulose 41.2%, xylogen 13.9%, ash content 1.3%, neutral washes 6.1%.

Liquid phase spectrometry analysis for the contents of monosaccharides obtained after hydrolysis.In hydrolyzed solution, the method for calculation of monose yield are as follows:

$Y=\frac{\mathrm{CV}}{1.1A\×M}\×100\%$

In formula, Y means monose yield (%); C means monosaccharide concentration in hydrolyzed solution (g/L); A means that in raw material, hemicellulose adds Mierocrystalline cellulose quality minute rate; V means the volume (L) of hydrolyzed solution; M means the quality (g) of raw material.

Dilute acid hydrolysis:

Take 50 gram bagasse and be placed in the stirred reactor that thermometer is housed, then add the hydrochloric acid soln of 400 milliliter 2%.With the oil bath heating, make temperature rise to fast 100 ℃, at this temperature, hydrolysis was added 10 gram bagasse after 1 hour, after 1 hour, had reacted, and controlling stir speed (S.S.) in reaction process is 80 rev/mins.

Washing and neutralization:

Stop after having reacted stirring, emit acid hydrolysis liquid, with 150 milliliters of clear water washing acid hydrolysis solid residues, obtain washings 1.

The acid solution obtained is neutralized with sodium hydroxide, obtain neutralizer.

Enzymic hydrolysis:

To the cellulase that adds 300 milliliters of clear water and 500 filter paper enzyme activities in reactor, regulator solution pH=5, then carry out enzymic hydrolysis to solid residue.Controlling temperature in reaction process is 50 ℃, and stir speed (S.S.) is 80 rev/mins.Hydrolysis is carried out after 24 hours stopping stirring, and emits enzyme hydrolyzate, with 120 milliliters of clear water detersive enzyme hydrolysis solid residues, and residue is pressed dry.Obtain washings 2.

Experimental result:

The total reducing sugar rate of recovery is 79.3%.It comprises the acid hydrolysis neutralizer, enzyme hydrolyzate, resulting whole monose in washings 1 and washings 2.Average concentration of sugars 39.9 grams per liters.

Embodiment 2

Raw material and analytical procedure:

With embodiment 1.

Dilute acid hydrolysis:

With embodiment 1.

Washing and neutralization:

Other conditions are with embodiment 1, but for washing acid hydrolysis solid residue be not clear water, but the washings 2 in embodiment 1.

Enzymic hydrolysis:

Other conditions are with embodiment 1.But for enzymic hydrolysis be not clear water, but the neutralizer in embodiment 1.

Experimental result:

The total reducing sugar rate of recovery is 75.4%.It comprises resulting whole monose in enzyme hydrolyzate and washings 1.Average concentration of sugars 72.1 grams per liters.

Embodiment 3

Raw material and analytical procedure:

With embodiment 1.

Dilute acid hydrolysis:

With embodiment 1.

Washing and neutralization:

Other conditions are with embodiment 1, but for washing acid hydrolysis solid residue be not clear water, but the washings 2 in embodiment 2.

Enzymic hydrolysis:

Other conditions are with embodiment 1.But for enzymic hydrolysis be not clear water, but the neutralizer in embodiment 2.

Experimental result:

The total reducing sugar rate of recovery is 75.7%.It comprises resulting whole monose in enzyme hydrolyzate and washings 1.Average concentration of sugars 72.4 grams per liters.

Claims (5)

1. a method that is prepared reductive monosaccharide by lignocellulose biomass by hydrolyzation, is characterized in that, comprises the steps: biomass material is placed in to stirred reactor, take diluted acid as catalyzer, at normal pressure or approach under the condition of normal pressure and be hydrolyzed.Be hydrolyzed rear washing residue, and in same reactor, it carried out to enzymic hydrolysis.

2. method according to claim 1, is characterized in that, mineral acid used is hydrochloric acid or sulfuric acid, and acid concentration is 1～3%, and the mass ratio of acid solution used and solid material is 6～10.

3. method according to claim 1, is characterized in that, the acid hydrolytic reaction time is 1～3 hour, and temperature of reaction is 90～110 ℃; The enzymatic hydrolysis reaction time is 12～48 hours, and temperature of reaction is 40～70 ℃.

4. method according to claim 1, is characterized in that, in hydrolytic process, will add the part biological raw material, in an amount equivalent to 15～40 of initial charge amount.

5. method according to claim 1, is characterized in that, also comprises the steps:

(1) acid solution of emitting after neutralization for the enzymic hydrolysis of next batch raw material.

(2) the residual washing-out water after enzymic hydrolysis is for the residual washing-out after the next batch material acidolysis, and the washings after acid hydrolysis is also as product.