CN101514349B

CN101514349B - Method for preparing fuel ethanol from bamboo fibers

Info

Publication number: CN101514349B
Application number: CN200810080614XA
Authority: CN
Inventors: 张金萍; 周本智; 王敬文; 杜孟浩
Original assignee: Research Institute of Subtropical Forestry of Chinese Academy of Forestry
Current assignee: Research Institute of Subtropical Forestry of Chinese Academy of Forestry
Priority date: 2008-02-21
Filing date: 2008-02-21
Publication date: 2012-01-04
Anticipated expiration: 2028-02-21
Also published as: CN101514349A

Abstract

The invention discloses a method for preparing fuel ethanol from bamboo fibers. The method comprises the following steps that: waste from bamboo (or other non-wood biomass) processing is used as a raw material, the raw material is cut, dried, crushed and passed through a 80-mesh sieve, the powder passing through the 80-mesh sieve is fine bamboo powder and the powder failing to pass through the 80-mesh sieve is coarse bamboo powder; the coarse bamboo powder is cooked in a mixed liquid of formic acid, acetic acid and water for hydrolyzing hemicellulose and delignification, and fibers are obtained and subjected to hydrolysis by an organic acid to form a reducing monosaccharide; the fine bamboo powder is hydrolyzed directly by the organic acid to form the reducing monosaccharide; the reducing monosaccharide obtained from the hydrolysis of the hemicelluloses, the fibers and the fine bamboo powder are detoxicated by an excess amount of Ca(OH)2, the pH of the mixture is reduced, and the fuel ethanol is obtained after fermentation and rectification. The method for producing the fuel ethanol ensures the yield of the fuel ethanol, reduces the energy consumption for hydrolysis, and allows the organic acid used for hydrolysis to be recycled. In addition, the process of the fuel ethanol preparation using the method requires less water, and reduces environmental pollution and cost.

Description

A kind of method for preparing alcohol fuel by bamboo fiber

Technical field

The present invention relates to a kind ofly prepare the method for alcohol fuel by bamboo fiber, promptly is raw material with the bamboo wood, obtains reducing sugar with organic acid hydrolysis bamboo fibers, and the reducing sugar of gained is fermented obtains alcohol fuel again.Wherein, used organic acid can be recycled.

Technical background

Along with the increase of world population and the raising of various countries' industrialization degree, the energy and environmental problem have become the focus that the whole world is paid close attention to.Fossil energy materials such as oil, coal and Sweet natural gas are petered out; Be protection environment and the target that realizes human kind sustainable development, from renewable resources particularly Wooden Biomass production chemical products with high added-value become the important development strategy of many countries and the hot fields of scientific research.Biomass energy is reproducible clean energy, utilizes biomass to produce Chemicals such as alcohol fuel for the concurrent ferment of raw material hydrolysis and receives extensive concern just day by day.

The technology that employing contains the farm crop preparing ethanol by fermentation of sugar and starch etc. has reached its maturity, and widespread use.Yet along with world population increases, staple food supply is nervous, is that the method for feedstock production alcohol fuel can not be launched on a large scale with food crop, and therefore adopting wood fibre is raw material, and it is significant to produce alcohol fuel through biomass by hydrolyzation.The three big components of forming Wooden Biomass are polymkeric substance such as Mierocrystalline cellulose, semicellulose and lignin, and wherein Mierocrystalline cellulose and semicellulose can be converted into ethanol, and theoretical yield can similar with grain (greater than 400L/t).See that from total amount Mierocrystalline cellulose, semicellulose and lignin are only the resource of renewable biomass the most widely that exists in the world.Bamboo belongs to grass, and Mierocrystalline cellulose and hemicellulose level are higher, and content of lignin is lower, and the phenolic acids secondary substance is also less.China has abundant bamboo plant resource as bamboo kingdom.Bamboo grove distributes extensively, and growth is fast, and it is short to cut down the phase, and output is high, is the important Forest Types of China.Therefore, bamboo can become the high-quality of producing alcohol fuel and abundant desirable feedstock.

Since the seventies in 20th century; The whole world has started the research boom of one cleaning substitute energy; The alcohol fuel that wherein derives from biomass energy with its recyclability, nonstaining property, do not cause Greenhouse effect and improve the characteristics such as explosion-proof performance of automobile and be acknowledged as one of renewable energy source of prospects for commercial application is arranged most, obtained extensive studies.Wood Adhesives from Biomass is that ethanol will be fermentable raw material-reducing sugar with Wood Adhesives from Biomass at first.Main at present mineral acid (rare or dense) and the enzymic hydrolysis filamentary material of adopting produces reducing sugar.

1. acid-hydrolysis method

Acid hydrolysis can be divided into dilute acid hydrolysis and concentrated acid hydrolysis, and dilute acid hydrolysis is a five-carbon sugar with hydrolysis of hemicellulose earlier usually at a lower temperature, and then adds acid hydrolysis residual solids under comparatively high temps, obtains hydrolysate glucose.The transformation efficiency of dilute acid hydrolysis sugar has only 50%, and has more depolymerization product can stop yeast fermentation to generate ethanol.Vitriol oil hydrolysis has 90% Mierocrystalline cellulose and semicellulose to be converted into fermentable sugars approximately, but the acid in the hydrolysis is difficult to reclaim, with in the lime with a large amount of gypsum of back generation, its value is very low.

2. enzyme hydrolysis method

Enzymic hydrolysis is a biochemical reaction, and biological material is put into hydrolysis reactor through after the pre-treatment, adds cellulase.Katalysis through cellulase is cellulose hydrolysis the monose that can ferment.This hydrolytic process reaction conditions is gentle, does not generate poisonous degraded product.But because the cost of production of cellulose enzyme is high at present, hydrolysis time is long, and productive rate relies on effects of pretreatment, equipment that pre-treatment need be bigger and higher running cost to a great extent.

Summary of the invention

The object of the present invention is to provide a kind of is the method for feedstock production alcohol fuel with the bamboo wood, and promptly with organic acid hydrolysis bamboo fine powder (or organic acid handled bamboo meal) preparation reducing sugar, the hydrolyzed solution that ferments then obtains alcohol fuel.

Conception of the present invention

The biomass by hydrolyzation process be exactly semicellulose and cellulose degradation be the process of pentose and glucose.But under hot conditions, pentose and glucose are also unstable, can further be degraded to by products such as furfural and hydroxymethylfurfural, to follow-up microbial fermentation deleterious impact.Therefore, hydrolytic process should reduce production of by-products as far as possible when improving sugared concentration.

Compare with Mierocrystalline cellulose, the hydrolysis ratio of semicellulose is easier to carry out.When temperature during at 100-105 ℃; Add certain density organic acid boiling, can stripping be enclosed in Mierocrystalline cellulose xylogen on every side, semicellulose is degraded to pentose simultaneously; Pentose and lignin are dissolved in the organic acid soln simultaneously; Thin up, lignin deposition leach, and will filtrate must the wood sugar liquid concentrator after concentrating.Isolated solid residue Mierocrystalline cellulose adds catalyzer hydrolysis at normal temperatures with organic acid again after the boiling, distills out organic acid and promptly obtains reducing sugar.Consider factors such as fermentation costs and equipment, pentose is become alcohol fuel with shehatae candida with fermentation by saccharomyces cerevisiae with follow-up cellulose hydrolysis gained reducing sugar.The lignin that reclaims can continue to prepare the chemical of other high added value or act as a fuel burning etc.

The present invention imagination with organic acid formic acid and acetate, is used formic acid when hydrolysis bamboo fine powder and the Mierocrystalline cellulose that prepared by the bamboo meal, and is made catalyzer with hydrochloric acid when boiling bamboo meal.

Technical scheme

1, the present invention is starting material with mao bamboon tankage (also being applicable to other non-timber biomass), and it is blocked, dries, pulverizes, crosses 80 mesh sieves.Through 80 mesh sieves be the bamboo fine powder, what cross 80 mesh sieves is the bamboo meal.

2, the bamboo meal is added in the pulp digester, with the mixed solution (liquid-solid ratio is 10: 1) of formic acid, acetate and water (ratio is 10/70/20) at 100-105 ℃ of following boiling 2h.Hydrolysis of hemicellulose is that wood sugar is dissolved in the acid solution, and lignin also is dissolved in the acid solution, and acid solution thin up lignin deposition is separated out, and gets the pentose liquid concentrator after cooking liquor is concentrated, and the gained solid residue is a cellulose components.

Above-mentioned gained solid residue Mierocrystalline cellulose adds 60 ℃ of hydrolysis 6h of 4% hydrochloric acid with 85% formic acid, and the formic acid underpressure distillation obtains reducing sugar after reclaiming.

3, the bamboo fine powder is added in the hydrolysis reactor, add 85% formic acid and 4% hydrochloric acid at 25: 1 at 60 ℃ of following hydrolysis 6h, after formic acid and salt acid recovery, obtain reducing sugar with liquid-solid ratio.

4, above-mentioned gained reducing sugar is mixed, after the detoxification treatment, with yeast saccharomyces cerevisiae and shehatae candida, 30 ℃ of fermentations 48 hours.

Description of drawings

Fig. 1 bamboo fiber prepares the alcohol fuel schematic flow sheet

The practical implementation method

Through instance the present invention is further specified below, but does not influence protection scope of the present invention:

Embodiment 1

The mao bamboon tankage are blocked, dry, pulverize.Cross 80 mesh sieves, through 80 mesh sieves be the bamboo fine powder, not through the person be the bamboo meal.Take by weighing 400 gram bamboo meal and add in the digestion reactors, with the mixed solution of liquid-solid ratio adding in 10: 1 formic acid/acetic acid/water (10/70/20), 105 ℃ of boiling 2h cross and filter 50.2% filter residue (staple is a Mierocrystalline cellulose); There is deposition to separate out behind the filtrating thin up, crosses and filter 16% xylogen; Test contains 20% piperylene after the concentrating filter liquor.

Embodiment 2

Embodiment 1 gained Mierocrystalline cellulose is added in the hydrolysis reactor, add 85% formic acid and 4% hydrochloric acid at 25: 1 at 60 ℃ of following hydrolysis 6h with liquid-solid ratio, underpressure distillation can obtain 55% reducing sugar after reclaiming formic acid.

Embodiment 3

Bamboo fine powder 400 grams that take by weighing among the embodiment 1 preparation add in the hydrolysis reactors, add 85% formic acid and 4% hydrochloric acid at 25: 1 at 60 ℃ of following hydrolysis 6h with liquid-solid ratio, with after formic acid and the hydrochloric acid underpressure distillation recovery, obtain 72.7% reducing sugar.

Embodiment 4

With embodiment 1,2,3 gained reductive hydrolysis liquid glucoses, with Ca (OH) ₂Adjust pH is used H again to 9-10 (excessive alkaline process overliming) ₂SO ₄Recall to pH5.5.With hydrolysis sugar liquid 150ml after the detoxification treatment and the yeast saccharomyces cerevisiae bacterial classification liquid concentrator 50mL mixed fermentation behind the multiplication culture; Ferment after 48 hours; Fermented liquid is drawn off, the bacterial classification in the reactor drum is kept 50mL as inoculum, in 72 hours, add hydrolyzed solution 400mL continuously.Leavening temperature is 30 ℃, and alcohol yied is 0.40g/g.

The used yeast bacterial classification is yeast saccharomyces cerevisiae (Saccharomyces cerevisiae Meyen et Hansen 2157) and shehatae candida (Candida shehatae) in the zymocyte liquid.

The acclimation method of used bacterial classification is following:

Substratum (g/L): peptone 3, yeast extract paste 2.5, MgSO ₄0.25, KH ₂PO ₄2.5, CaCl ₂0.25, glucose 15.00,121 ℃ of sterilizations of pH5.0-5.5. substratum 20 minutes.

The enrichment culture of bacterial classification: with the bacterial classification inoculation of preservation in the 100mL liquid nutrient medium, 30 ℃, 80rpm activation 24h.Change fresh culture then into, breed 48h down in similarity condition.

Claims

1. one kind is the method that the hydrolysis of raw material organic acid prepares alcohol fuel with the bamboo wood, it is characterized in that, comprises the steps:

A, be starting material, it blocked, dry, pulverize, cross 80 mesh sieves with the mao bamboon tankage, through 80 mesh sieves be the bamboo fine powder, mistake 80 mesh sieves is the bamboo meal;

B, boiling bamboo meal, are removed lignin at hydrolyzed hemicellulose, isolate Mierocrystalline cellulose: with the bamboo meal with formic acid/acetic acid/water mixed solution in 100-105 ℃ of boiling 2h; Remaining residue is a Mierocrystalline cellulose after the boiling, adds entry in the filtrating lignin deposition is leached, and hydrolysis of hemicellulose is that pentose is dissolved in the acid solution, after evaporation concentration, obtains the pentose liquid concentrator;

C, organic acid hydrolysis de-fibering element: the formic acid with 85% adds hydrochloric acid and makes catalyzer, the Mierocrystalline cellulose of hydrolysing step b preparation, and liquid-solid ratio 25: 1, at 60 ℃ of hydrolysis 6h, underpressure distillation Separation and Recovery formic acid obtains the reductibility liquid glucose;

D, organic acid hydrolysis bamboo fine powder: the bamboo fine powder is added hydrochloric acid with 85% formic acid make catalyzer, liquid-solid ratio 25: 1, at 60 ℃ of hydrolysis 6h, underpressure distillation Separation and Recovery formic acid obtains the reductibility liquid glucose;

E, with step b, c, d hydrolysis gained liquid glucose detoxification secondary fermentation.

According to claim 1 said a kind of be the method that the hydrolysis of raw material organic acid prepares alcohol fuel with the bamboo wood, it is characterized in that among the said step e, the detoxification process is with excessive Ca (OH) ₂Adjust pH is used H again to 9-10 ₂SO ₄Recall to pH5.5.

According to claim 2 said a kind of be the method that the hydrolysis of raw material organic acid prepares alcohol fuel with the bamboo wood, it is characterized in that, after the step e adjust pH; With liquid glucose 150ml after the detoxification treatment and the yeast saccharomyces cerevisiae bacterial classification liquid concentrator 50mL mixed fermentation behind the multiplication culture;, after 48 hours fermented liquid is drawn off 30 ℃ of fermentations, the bacterial classification in the reactor drum is kept 50mL as inoculum; Liquid glucose 400mL in 72 hours after the continuous adding detoxification treatment; Obtain tunning, carry out rectifying, collect ethanol wherein.