CN102827898A

CN102827898A - Method for vacuum-assisted hydrothermal pretreatment of biomass

Info

Publication number: CN102827898A
Application number: CN2011101579681A
Authority: CN
Inventors: 徐建; 彭华栋
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2011-06-13
Filing date: 2011-06-13
Publication date: 2012-12-19
Anticipated expiration: 2031-06-13
Also published as: CN102827898B

Abstract

The invention discloses a method for vacuum-assisted hydrothermal pretreatment of biomass. The method comprises the steps of smashing the biomass into particles with granularity of 0.1-50 mm; putting the smashed biomass particles into an autoclave; adding a proper amount of degassed tap water or distilled water to make the mass ratio of the biomass to water 1:10-1:50; pumping superfluous air from the autoclave, to make an initial relative vacuum degree in the autoclave maintain at -0.01-0.1 MPa; keeping a pre-treating temperature of 150-230 DEG C for 1-30 min; stopping heating; taking out the materials when the temperature in the autoclave is reduced to lower than 50 DEG C; and finishing the pretreatment. The method employs the vacuum-assisted hydrothermal method to pre-treat the biomass, keeps the internal portion of the reaction system in a relative vacuum state after a certain amount of air is removed; so that risks of side reactions in the hydrothermal pretreatment process caused by the presence of oxygen are reduced; treating effects are enhanced; inhibitors having potential inhibiting effects for subsequent utilization can not produced; or the produced inhibitors have very low concentration which is insufficient for influencing the subsequent utilization.

Description

The method of vacuum hydro-thermal preprocessing biomass

Technical field

The invention belongs to the biomass preprocessing technical field, particularly a kind of method of novel evacuated hydrothermal pretreatment biomass.

Background technology

Be based upon the modern chemistry industry on the fossil resource bases such as oil, coal and Sweet natural gas, have tangible dependent resource.Because the reserves of Nonrenewable energy resources are limited, make human development face the potential crisis.Simultaneously, derive by these resources or many chemical of being transformed become the source that environment is polluted after use.The dual-pressure of resource and environment forces people to seek can to substitute the novel resource of fossil resource, and a key property of this resource at first should be renewable.Lignocellulose a kind of renewable resources that exactly comes to this has the potentiality of production bulk chemical, fine chemicals, medicine intermediate, the energy etc., is considered to substitute the optimal selection of fossil resource.

At present, physics conversion method, chemical transformation and biotransformation method are mainly adopted in the conversion of lignocellulose.Biotransformation method becomes the focus of research so that its mild condition, efficiency of pcr product are high, equipment requirements is low, energy consumption is low.Typical lignocellulose bioprocess comprises: biomass collection and transportation, pre-treatment, enzymatic saccharification, fermentation, product reclaim and the byproduct comprehensive utilization.Wherein, pre-treatment has occupied a central position, and it has been related to each link of lignocellulose biotransformation directly or indirectly.Because biomass are of a great variety, textural difference, investigators have invented a lot of pretreatment technology, and, hydro-thermal, microwave quick-fried like vapour, ammonia is quick-fried and technologies such as the plasma body of recent rise, ionic liquid.Wherein, the hydrothermal pretreatment technology is easy to amplify with it and advantage such as environmentally friendly, and enjoys favor.But in the present hydrothermal pretreatment technology,, cause producing more potential inhibition in the preprocessing process, later use is had a negative impact owing to have too much air in the system.Be head it off; Patent of the present invention has adopted the tap water that removes air or deionized water to mix mutually with lignocellulose and has inserted in the reaction kettle; With vacuum pump the unnecessary air in material top in the system is pumped simultaneously, to cause the generation of too much side reaction in the minimizing system as far as possible owing to existing of oxygen.

Summary of the invention

The pretreated method of [goal of the invention] biomass is varied, produces the bigger potential inhibition to the toxic effect of later use of concentration but distinct issues are preprocessing process.In order to remove these inhibitions, must increase the detoxification program, this has just caused production cost sharply to rise indirectly.This shows that the pretreatment technology of inventing a kind of nothing or a small amount of potential inhibition generation is imperative.This also is the place of the object of the invention.

[design of the present invention]

In the hydrothermal pretreatment process; Only make water as medium, the oxonium ion that the water autoionization produces under the high temperature acts on biomass, thereby generates acetic acid, uronic acid and phenolic acids etc.; Cause the further degraded of biomass, this process be known as biomass from the body hydrolysis.Mainly act on the semicellulose in the little element of wooden fibre from the body hydrolysis, simultaneously can be with a small amount of lignin degradation.If in the hydrothermal pretreatment system, there is too much air (oxygen), then can causes too much xylogen under hot conditions, to be degraded, and further be oxidized to inhibition the toxic effect of later use.

If in preprocessing process, the air in the system is removed as far as possible, then can farthest reduce the generation of side reaction in the preprocessing process.Based on this, the present invention has been proposed.

[technical scheme of the present invention] essential characteristic of the present invention is following:

(1) biomass material that at first will handle cuts off and pulverization process, makes its granularity scope between 0.1mm～50mm; (2) tap water or deionized water are handled through vacuum degassing machine or ultrasonic degas device; (3) biomass are inserted reaction kettle after, add tap water or deionized water through the degassing, making solid-to-liquid ratio is 1: 10～1: 50; (4) extract the air of material top in the autoclave out with vacuum pump, make the inner relative vacuum degree of reaction kettle for-0.01MPa～-0.1MPa; (4) according to the difference of utilizing purpose after the kind of biomass and the pre-treatment; Reaction kettle is heated to 150 ℃～230 ℃, and after under target temperature, keeping 1min～30min (5) insulation to finish, question response still temperature is reduced to below 50 ℃; Take out material, accomplish pre-treatment.

Described biomass material is a corn straw, rice straw, wheat stalk, beanstalk, Chinese sorghum, agricultural crop straws such as sweet sorghum; Clover, herbage such as hybrid giant napier; Wood shavings, the each several part of xylophytas such as twig; The each several part of Chinese silvergrass, switchgrass, the living willow equal energy source plant of speed.

The pre-treatment purpose comprises that pretreated raw material is used for enzymolysis produces sugar; Pretreated raw material is used to produce alcohol fuel; Butanols, liquid fuel or Chemicals such as Succinic Acid are used for solid state fermentation matrix with pretreated raw material; Pretreated raw material is used to produce animal-feed, pretreated matrix is used for anaerobically fermenting.

The present invention has following characteristics and advantage:

1. this pre-treatment belongs to the vacuum hydrothermal pretreatment, and the air in the removal system as far as possible in the treating processes can reduce because the preprocessing process side reaction odds that the existence of oxygen in the air causes so to greatest extent, and and then the generation of minimizing inhibition;

2. cause vacuum state through extracting the inner air of autoclave out, more traditional hydrothermal pretreatment of rate of heating and time is increased;

3. more traditional hydrothermal pretreatment need not to increase the detoxification step, and production cost is significantly reduced;

4. need not to add chemical such as soda acid in the treating processes, avoided pollution, effectively reduced the pre-treatment cost.

Embodiment

Through embodiment the present invention is further specified below.

Embodiment 1

Wheat stalk is ground to 1mm, inserts in the autoclave, add through the tap water after the degassing; Make system solid-to-liquid ratio (Wheat Straw: be 1: 15 water), after mixing, cover reaction kettle; Extract air in the reaction kettle out with vacuum pump, make in the still start-up phase that vacuum tightness is-0.08MPa, reacting by heating still to 180 ℃; Behind the constant temperature 15min, accomplish pre-treatment.

Get handle after the exsiccant stalk under 40 ℃, with cellulase degradation 48 hours, the cellulase consumption was the 30IU/g substrate in the damping fluid of pH4.8.Cellulosic enzymatic hydrolyzation is 80%.Corresponding without pretreated wheat stalk, its enzymatic hydrolyzation has only 23%.

Embodiment 2

Corn straw is ground to 2mm, inserts in the autoclave, add through the tap water after the degassing; Make system solid-to-liquid ratio (corn straw: be 1: 20 water), after mixing, cover reaction kettle; Extract air in the reaction kettle out with vacuum pump, make in the still start-up phase that vacuum tightness is-0.09MPa, reacting by heating still to 195 ℃; Behind the constant temperature 10min, accomplish pre-treatment.

Get and handle after the exsiccant corn straw carries out the synchronous saccharification ethanol fermentation under 38 ℃, the cellulase consumption is the 30IU/g substrate.Fermented 120 hours, the ethanol yield reaches 76% of theoretical value.And without pretreated corn straw, its ethanol conversion is merely 24% of theoretical value.

Embodiment 3

Rice straw is ground to 3mm, inserts in the autoclave, add through the tap water after the degassing; Make system solid-to-liquid ratio (rice straw: be 1: 30 water), after mixing, cover reaction kettle; Extract air in the reaction kettle out with vacuum pump, make in the still start-up phase that vacuum tightness is-0.1MPa, reacting by heating still to 185 ℃; Behind the constant temperature 12min, accomplish pre-treatment.

Pretreated rice straw carries out the viride solid state fermentation as the product enzyme substratum of cellulase.Raw material after the processing and wheat bran carried out proportioning according to 4: 1, added inorganic salt solution (ammonium sulfate 6% (w/w), the sal epsom 3% (w/w) of 1: 2.5 (w/w); Potassium hydrogenphosphate 1.5% (w/w)), behind the 30min that sterilizes under 121 ℃, cooling; The viride seed liquor of inoculating 1: 0.5 (w/v) is fermented, and temperature is 30 ℃, ferments after 5 days; Enzyme is lived and is the 58IU/g dry medium, considerably beyond contrast (being untreated) 13IU/g dry medium.

Claims

1. the method for a vacuum hydro-thermal preprocessing biomass, its step comprises:

(1) biomass material is cut off and pulverization process, make its granularity scope between 0.1～50mm;

(2) with the processing that outgases of the used tap water of preprocessing process or deionized water;

(3) biomass of step (1) being handled join in the autoclave;

(4) in autoclave, add tap water or the deionized water that step (2) was handled, the mass ratio of regulating biomass and water is 1: 10～1: 50, mixes;

(5) to extract unnecessary air in the autoclave out with vacuum pump, make autoclave inside be in the relative vacuum state, the relative vacuum degree is-0.01MPa～-0.1MPa;

(6) after temperature of reaction kettle reaches 150 ℃～230 ℃, keep stopping heating behind 1min～30min;

(7) question response still temperature is reduced to below 50 ℃, takes out material, accomplishes pre-treatment.

2. method according to claim 1 is characterized in that: described biomass are corn straw, rice straw, wheat stalk, beanstalk, Chinese sorghum, sweet sorghum, agricultural crop straws such as peanut seedling or shell; Clover, hybrid giant napier, herbage such as reed; Wood shavings or sawdust, the each several part of xylophytas such as twig; The each several part of Chinese silvergrass, switchgrass, the living willow equal energy source plant of speed.

3. method according to claim 1 is characterized in that: described pre-treatment purpose comprises that pretreated raw material is used for enzymolysis produces sugar, is used to produce alcohol fuel with pretreated raw material; Butanols; Liquid fuel or Chemicals such as Succinic Acid are used for solid state fermentation matrix with pretreated raw material, and pretreated raw material is used to produce animal-feed; Pretreated raw material is used to produce crop fertilizer, pretreated matrix is used for anaerobically fermenting.