CN113024836A

CN113024836A - Industrial production system and method for polymer-grade cellulose lactic acid with fulvic acid co-production

Info

Publication number: CN113024836A
Application number: CN202110241357.9A
Authority: CN
Inventors: 白博; 白嘉妮; 王东; 刘玉芳; 史晓菲; 王勇
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-03-04
Filing date: 2021-03-04
Publication date: 2021-06-25

Abstract

The invention relates to a factory production system and a method of polymer grade cellulose lactic acid for co-production of fulvic acid, wherein the purification of polymer grade lactic acid is arranged in the whole project system for grasping and designing, firstly, the purification of lactic acid is widened from single post-treatment to pre-treatment removal, in-process control and post-treatment purification clearance range treatment, the known purification process is adopted for purification, secondly, the fiber raw material is purified and separated into high-purity cellulose components and non-cellulose components through pretreatment, the cellulose components are used for producing polymer grade lactic acid, the non-cellulose components are used for producing fulvic acid, thirdly, the complete technical scheme and algorithm for the transfer treatment of lactic acid fermentation waste liquid and sewage are provided, and finally, the fulvic acid with high added value and the polymer grade lactic acid are obtained. Realizes the high added value comprehensive utilization of the cellulose raw material, and overcomes the problems in the industrialization process of producing polymer-grade lactic acid and cellulose ethanol by saccharification and fermentation of a series of cellulose raw materials. The invention is also suitable for the industrial production of the cellulosic ethanol.

Description

Industrial production system and method for polymer-grade cellulose lactic acid with fulvic acid co-production

Technical Field

The invention relates to the fields of comprehensive utilization of crop straw resources, biochemical engineering, fermentation engineering and production of cellulose lactic acid and polylactic acid, in particular to a system and a method for purifying and producing polymer-grade lactic acid for co-producing fulvic acid.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

With the increasing requirement of human on environmental protection, degradable plastics are coming to a huge industrial heat tide. The degradable plastic mainly has three sources of petroleum base, starch base and cellulose base, the petroleum base and grain starch base raw materials have higher industrialization degree at present, but the petroleum resource can not be regenerated, and the starch base raw materials have the problems of competing for grains with people and competing for land with grains.

The cellulose raw material has the advantages of large quantity, regeneration and sustainable development, and has wide prospect in producing polylactic acid by replacing grain and petroleum with the cellulose raw material.

The purification and purification of lactic acid become the main cost component of polylactic acid production, and the purification and purification of lactic acid become the bottleneck of polylactic acid production, which is the primary technical subject facing the polylactic acid production.

A great deal of research has been around purification and purification of lactic acid, but most of them are limited to purification and purification techniques of lactic acid, and are limited to be closed afterwards, and the problems are not put into the whole production system to be investigated and researched and solve:

the patent "method for producing lactic acid and polylactic acid (application No. CN 200980152863.8)" suggests the influence of impurities on lactic acid performance and provides an index for optimizing the content of impurities. The first feature of the lactic acid of the present invention is that the content of (1) methanol as an impurity in a 90% aqueous lactic acid solution is 70ppm or less, preferably 65ppm or less, more preferably 50ppm or less, and still more preferably 30ppm or less. The second feature of the lactic acid of the present invention is that the content of (2) pyruvic acid as an impurity in a 90% lactic acid aqueous solution is 500ppm or less, preferably 400ppm or less, and more preferably 300ppm or less. The third feature of the lactic acid of the present invention is that the content of (3) furfural as an impurity in the 90% lactic acid aqueous solution is 15ppm or less, preferably 10ppm or less, and more preferably 5ppm or less. The fourth feature of the lactic acid of the present invention is that the content of (4) 5-hydroxymethylfurfural, which is an impurity in a 90% aqueous lactic acid solution, is 15ppm or less, preferably 10ppm or less, and more preferably 5ppm or less. The fifth feature of the lactic acid of the present invention is that the content of methyl (5) lactate as an impurity in the 90% aqueous lactic acid solution is 600ppm or less, preferably 400ppm or less, and more preferably 100ppm or less. The sixth feature of the lactic acid of the present invention is that the content of (6) acetic acid as an impurity in the 90% lactic acid aqueous solution is 500ppm or less, preferably 400ppm or less, and more preferably 300ppm or less. The seventh feature of the lactic acid of the present invention is that the content of (7) 2-hydroxybutyric acid as an impurity in a 90% aqueous lactic acid solution is 500ppm or less, preferably 300ppm or less, and more preferably 200ppm or less. The purity of lactic acid obtained by microfiltration, nanofiltration and reverse osmosis is preferably 95% or more, more preferably 99% or more, and most preferably 99.9% or more. The patent does not refer to the source of the impurities.

Jiang Li et al, "research on L-lactic acid production using lignocellulose" (from agricultural products Jia (academic Press 2007: 11 month, 11 th (118 th overall)), pointed out that in the process of producing L-lactic acid from wood fiber raw materials, the fermentation liquor is brownish yellow due to pigment contained in the raw materials such as straw, and the like, and the fermentation liquor needs to be decolored to remove the pigment, so that the requirements of consumers can be met. The decolorization process is mainly based on the adsorption theory of an adsorbent, and decolorizers such as powdered activated carbon, K-5 resin, 122 resin and the like are commonly used for decolorization at present. Meanwhile, the components of the lactic acid fermentation liquid are complex and different due to different raw materials and fermentation processes. Besides lactic acid, the fermentation broth also contains various impurities such as thalli, residual sugar, protein, pigment, colloid, organic heteropolyacid and inorganic salt, which are derived from raw materials, unconsumed nutrient solution or intermediate byproducts of fermentation. Therefore, the extraction of lactic acid from lactic acid fermentation broth is a major task. The method for extracting lactic acid from lactic acid fermentation liquor mainly comprises a calcium salt method, an extraction method, an adsorption method, a membrane method, a molecular distillation method, a reduced pressure distillation method and the like.

The patent "a method for purifying, recovering and concentrating sugar in lignocellulose prehydrolysis liquid (application number: CN 201010100480.0)", relates to a method for recovering, concentrating and removing toxicity inhibitors from the sugar in the lignocellulose prehydrolysis liquid by using nanofiltration technology. The method is realized by the following scheme: firstly, adjusting the pH value of lignocellulose prehydrolysis liquid to be 2.0-5.0, and removing suspended impurities through filtering pretreatment; and then, a nanofiltration membrane is adopted to concentrate sugar and remove inhibitors, the sugar such as glucose and xylose is intercepted by the nanofiltration membrane, the weakly acidic inhibitors (formic acid, acetic acid, levulinic acid and the like) and the furfural inhibitors (furfural, 5-hydroxymethylfurfural and the like) continuously permeate the nanofiltration membrane, and various inhibitors in the prehydrolysis liquid and various sugar in the concentrated prehydrolysis liquid are removed, so that the purification, recovery and concentration of the sugar in the prehydrolysis liquid are realized, and the fermentability of the sugar is improved.

In the advanced research on the L-lactic acid decolorization process (9 2010-9 th of volume 18 of fine and special chemicals), when L-lactic acid is prepared from starch raw materials through lactic acid bacteria fermentation, in the sterilization process of a fermentation medium, part of glucose is subjected to dehydration decomposition reaction under the condition of heating to generate substances such as levulinic acid, and the substances are polymerized by themselves or combined with organic substances contained in starch to generate pigments, so that the quality of L-lactic acid products is influenced. And the active carbon decoloring process is researched, and the decoloring rate reaches 96.27% under the optimal decoloring condition. The pigment problem of the substrate raw material is not involved.

The patent "a method for producing polylactic acid (application No.: CN 202010594402.4)" comprises:

(i) inoculating lactic acid fermentation strains into a lactic acid fermentation culture medium for fermentation to obtain fermentation liquor containing lactate;

(i i) separating the fermentation liquid to obtain lactic acid;

(ii) synthesizing polymer-grade lactide by using lactic acid as a raw material;

(iv) and polymerizing the polymerization-grade lactide in a polymerization reaction device to obtain the polylactic acid.

The problem of the source of the lactic acid impurities is not involved.

The patent 'a process method for preparing high-purity L-lactic acid (CN 200610023613.2)', provides a method for preparing high-purity L-lactic acid, which comprises a), feeding L-lactic acid pretreated by one or more methods of extraction, crystallization, decoloration, ion exchange or membrane separation into a concentrator, and concentrating under 0.5-0.95 Mpa at 50-90 ℃; b) feeding the L-lactic acid from the concentrator to at least 2 stages of short path distillation devices combined in series for continuous distillation; wherein: distilling by using a first-stage short-path distillation device under the conditions of 50-500 Pa and 50-130 ℃, sending heavy components obtained after distillation into a second-stage short-path distillation device, and collecting light component products to obtain high-purity L-lactic acid; and distilling the heavy component L-lactic acid from the first-stage short-path distillation device in a second-stage short-path distillation device under the conditions of 10-500 Pa and 100-120 ℃, and collecting a light component product to obtain the high-purity polymerization-grade L-lactic acid. The treatment problems of distilled water and distillation residues are not involved.

Bin, eds "green plastic polylactic acid" (chemical industry press, beijing, 9 months 2007), p21, indicated that the theoretical yield of saccharification of corn was 60%, the theoretical yield of fermentation of glucose to L-lactic acid was 85%, and the theoretical yield of polymerization of lactic acid to PLLA was 80%. The introduction mentions that the lactic acid is produced by batch fermentation process in the early commercial scale production process of the American MaizeProducts company, and the concentration of the lactic acid obtained from 150g/L glucose reaches 120-135 g/L. The treatment of the lactic acid fermentation waste liquid is not involved.

Zhang Jingqiang et al, "progress in the preparation of Biomass Plastic from lignocellulosic fermented lactic acid" (national emphasis laboratory of pulp and paper making engineering, university of south China, Guangdong, 510640, Yunnan chemical engineering, vol. 2, 2009, vol. 36, No. 1, analysis and experimental verification that acetic acid in lactic acid is produced by hydrolysis of hemicellulose:

C₆H₁₂0₆—2C₃H₆0₃

C₅H₁₀0₅—C₃H₆0₃+CH₃COOH

note that Guadalupe bunts et al in Spain, prepared lactic acid by fermenting a hydrolysate thereof with Lactobacillus pentosus CECT-4023T (ATCC-8041) using trimmed branches and leaves of grapevine as a raw material. They found that the constituents of the hydrolysate were mainly glucose (12.0g g/L), xylose (17.5g/L) and arabinose (4.3g/L), and that acetic acid, the main by-product, appeared only when all the glucose was consumed, indicating that acetic acid was mainly from the metabolism of xylose and arabinose. But no method for removing lactic acid by pretreatment is proposed.

Analysis suggests the source of pyruvate, and in the presence of excess substrate, lactic acid bacteria grow anaerobically, energy substances such as glucose are converted to pyruvate via the EMP metabolic pathway, and pyruvate continues to be metabolised to lactate. As shown in fig. 3.

The patent "a method for removing inhibitors from pre-hydrolyzed solution of lignocellulose" (application number CN201010119148.9) "discloses a method for removing/recovering toxic inhibitors from pre-hydrolyzed solution of lignocellulose and concentrating sugar by using pervaporation technology. The method is realized by the following scheme: firstly, adjusting the pH value of a prehydrolysis liquid obtained by lignocellulose pretreatment to 2.0-5.0, and filtering to remove suspended impurities; then, a pervaporation membrane is adopted for removing/recovering the inhibitor, sugar such as glucose, xylose and the like is intercepted by the pervaporation membrane, weakly acidic inhibitors (formic acid, acetic acid and levulinic acid) and furfural inhibitors (furfural and 5-hydroxymethyl furfural) continuously permeate the pervaporation membrane, and simultaneously, inhibitor components with higher concentration can be obtained at the permeation side. Therefore, the method can remove various inhibitors in the prehydrolysis liquid and simultaneously reserve various sugars in the prehydrolysis liquid, thereby realizing purification and concentration of the sugars in the prehydrolysis liquid, improving the fermentability of the sugars and recycling the inhibitor components. The method comprises the following steps:

(1) lignocellulose prehydrolysis liquid (80 g/L of xylose, 20g/L of glucose, 10g/L of arabinose, 1g/L of mannose, 1g/L of galactose, 5g/L of formic acid, 20g/L of acetic acid, 4g/L of levulinic acid, 40g/L of furfural, 5g/L of 5-hydroxymethylfurfural and pH3.0) obtained by dilute acid pretreatment enters a microfiltration component through a feeding pump to remove suspended matter impurities. The pressure in the microfiltration component is 0.1-0.2 MPa, the temperature is 25 ℃, and the aperture of the filter membrane is 0.45 mu m.

(2) And (2) the permeate liquid obtained in the step (1) enters a feed liquid tank, is heated to 50 ℃ by a super constant-temperature water bath, is conveyed to a flat plate type pervaporation membrane assembly by a feed pump, and returns to the feed liquid tank. The pervaporation membrane is a self-made polydimethylsiloxane/polypropylene nitrile composite membrane. The degree of vacuum on the permeate side was measured by a vacuum gauge and maintained at about 0.2 kPa. The permeate gas that permeates the membrane is collected at the downstream side in a cold trap by a two-stage liquid nitrogen condensing unit. All the liquid collected in the two-stage condenser was mixed and used as permeate for the membrane to analyze and evaluate the performance of the system. And stopping pervaporation operation until the concentration of weak acidity inhibitors (formic acid, acetic acid and levulinic acid) in the feed liquid tank is less than 1.0g/L and the concentration of furfural inhibitors (furfural and 5-hydroxymethyl furfural) is less than 0.1 g/L. The total average permeation flux of the pervaporation membrane during operation was 1200 g/(m)²H). The concentration of each component in the lignocellulose pre-hydrolyzed solution obtained at the moment is respectively as follows: 128g/L of xylose, 32g/L of glucose, 15g/L of arabinose, 1.5g/L of mannose, 1.6g/L of galactose, 0.65g/L of formic acid, 0.82g/L of acetic acid, 0.43g/L of levulinic acid, 0.02g/L of furfural and 0g/L of 5-hydroxymethylfurfural. The average concentration of each component in the permeate is as follows: 13.2g/L of formic acid, 48.4g/L of acetic acid, 11.4g/L of levulinic acid, 106.2g/L of furfural and 13.9g/L of 5-hydroxymethylfurfural. The method can greatly reduce fermentation inhibitors, but does not disclose the direction of waste liquid formed by filtering products.

The patent "method for cleanly producing lactic acid by fermentation method (patent No. CN 200810114988.9)" indicates the reason of black color generated in the purification process of lactic acid, namely that lime milk is needed to raise the pH value of fermentation liquor to 9.5-10 during pretreatment of the fermentation liquor, acid is needed to adjust the pH value of the fermentation liquor to 4-5 during decolorization, and then the pH value of filtrate is adjusted back to 9-10 to denature and flocculate protein. During the post-treatment process of the fermentation residual sugar, the fermentation residual sugar reacts with the existing nitrogenous substances to generate melanoidin, and is decomposed into furfural when meeting acid, so that the furfural is converted into a colored substance.

The invention is especially provided for overcoming the defects of the prior art.

Disclosure of Invention

In order to overcome the problems, the invention provides a system and a method for industrially producing polymer grade cellulose lactic acid with fulvic acid coproduction.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

in a first aspect of the present invention, a factory production method of polymer grade cellulose lactic acid with fulvic acid co-production is provided, which comprises:

pretreating and separating the fiber raw material to obtain purified cellulose and fulvic acid;

producing lactic acid from the purified cellulosic component and purifying the lactic acid;

producing fulvic acid from the non-cellulosic component;

limiting the dosage of sodium ions in the pretreatment and saccharification, fermentation and purification processes;

and (3) carrying out transfer treatment on the lactic acid waste liquid and sewage to finally obtain the fulvic acid with high added value and the high-purity polymer grade cellulose lactic acid.

The problems and objects to be solved by the present invention are:

1. the method is used for producing polymer-grade cellulose lactic acid, so that impurities in lactic acid fermentation liquor are reduced, and the difficulty in purification of lactic acid is simplified and reduced;

2. the economic benefit of comprehensive utilization of cellulose polylactic acid project resources is improved by co-producing fulvic acid;

3. transferring the sewage generated by saccharification, fermentation, purification and purification to a pretreatment unit for treatment.

The idea of solving the problems is as follows:

the production of cellulose polylactic acid with the co-production of yellow rot is grasped as an independent operation project, and the feasibility system design of technology and economy is carried out on the basis of the sustainable operation of the whole project, and all related elements are systematically integrated.

Firstly, the purification and purification of lactic acid, which are key links of the technology and cost of polylactic acid production, are started to determine the impurities and sources of lactic acid.

Secondly, purifying lactic acid impurities afterwards, keeping the lactic acid impurities in a later stage, putting eyes to a pre-treatment early control and saccharification fermentation central control unit according to the source or the generated root source of the impurities, changing the pre-treatment early control and saccharification fermentation central control unit into a pre-treatment + middle-post total system process, namely, carrying out pre-treatment removal, central control and keeping the lactic acid impurities in a later stage, and finally obtaining the polymer grade lactic acid.

Thirdly, the cellulose purification, the reduction and the removal of lactic acid impurities are combined with the production of fulvic acid, and the comprehensive utilization benefit of the fiber raw material is improved. The industrial competitiveness of the cellulose polylactic acid project is improved, and the sustainable development of the cellulose ethanol industry is guaranteed. From the viewpoint of expanding the range of view, cellulose polylactic acid is defined to the category of comprehensive utilization of fiber resources, and the utilization of single cellulose or cellulose + hemicellulose is changed into the comprehensive utilization of cellulose + hemicellulose + lignin, namely, the cellulose or cellulose + hemicellulose produces lactic acid, the lignin which is used as a burden in the past is used for producing fulvic acid with higher added value, and simultaneously, the pollution substance system which troubles the lactic acid production is stored into the fulvic acid to be changed into the effective component of the fulvic acid.

Fourthly, the sewage generated by the saccharification, fermentation and purification of the lactic acid is transferred to a pretreatment unit, and is combined with the production of the fulvic acid, so that the industrial dilemma of cellulose lactic acid is broken through. The purification and purification of lactic acid, the purification and pretreatment of fiber raw materials, the sewage of a pretreatment unit and the sewage of a saccharification fermentation purification unit are put into a production system for solution, the single lactic acid purification technology is changed into the lactic acid purification of the system, and the redesign and the operation control of the production system are carried out.

In a second aspect of the invention, a technical scheme and a method system of a system for separating all fiber raw materials into cellulose components and non-cellulose components, producing lactic acid by using the cellulose components, and producing fulvic acid by using all non-cellulose components such as separated lignin and the like are provided; the method is also suitable for the industrial production of the cellulosic ethanol; the fiber raw materials comprise various wood fibers, non-wood plant fibers, various crop straws, wastes and residues and wastes of industrial processing, and specifically comprise: at least one of wheat and barley straws and wheat bran, corn straws and corncobs and industrial residues thereof, rice and rice chaff, cotton straws and cotton boll hull cotton seed hulls, bean straws, rape stalks, peanut hulls, various tree twigs and offcuts, reeds, bamboos, bagasse, wattle and palm fruit hulls.

Another view to solve the problem is: the frustration and experience training encountered in the industrialization of the cellulose ethanol are summarized, and the cellulose lactic acid is designed and operated as an industrial project according to the brand-new technical thought of a system.

In comparison, the industrialization of producing cellulosic ethanol from wood fiber is similar to the industrialization of producing cellulosic polylactic acid. The frustration and the dilemma encountered in the previous industrialization process of cellulosic ethanol are that the industrialization of the just started cellulosic polylactic acid is just as likely to be encountered and cannot be exceeded.

From the process flow, the process flow of the cellulosic ethanol comprises the following steps: the technological process of pretreatment, purification and detoxification of fiber raw material, saccharification, fermentation to obtain ethanol, purification, concentration and ethanol, and the cellulose polylactic acid comprises the following steps: the fiber raw material is pretreated and purified, detoxified, saccharified, fermented to obtain lactic acid, purified to obtain polymer-grade lactic acid, polylactic acid, and the two are completely superposed in the fiber raw material pretreatment, purification, detoxified and saccharified stages, and are just branched from the beginning of fermentation, and different fermentation strains are added into the cellulose saccharified liquid to respectively produce ethanol and lactic acid.

The method can be used for analyzing the current industrial production situation of the cellulose ethanol in the world to draw a conclusion that: "it is generally accepted that a key factor in the failure of the industrialization of cellulosic ethanol is the significant drawbacks of the pretreatment technology. The possibility of large-scale industrialization (production of cellulosic ethanol and cellulosic lactic acid) by adopting the existing biorefinery technology is basically lost, and the biorefinery technology urgently needs to realize breakthrough of the cellulosic ethanol industrialization technology by a novel technical thought.

Therefore, it is necessary to redefine the problem of the new technical route and to integrate the industrial elements again, thereby designing a new technical solution.

The invention has the beneficial effects that:

(1) the impurity content of the lactic acid is preliminarily removed from the source from the pretreatment unit and is controlled from the saccharification and fermentation unit, so that the difficulty of purifying the lactic acid after the lactic acid purification unit is reduced;

(2) components except cellulose are converted into fulvic acid with high added value through pretreatment, waste is turned into wealth, and the comprehensive economic benefit and the industrial competitiveness of the vitamin lactic acid polylactic acid are effectively improved;

(3) the sewage generated by the saccharification, fermentation and purification of the lactic acid is transferred, the system advantages of cellulose lactic acid and polylactic acid for co-producing fulvic acid are exerted, and the water treatment burden of the cellulose lactic acid is shared and reduced;

(4) toxic and side effects of pretreatment by-products on saccharification and fermentation are eliminated through pretreatment and detoxification;

(5) solid state flow of fiber raw material: pretreating, cooking and hydrolyzing, separating, deeply removing hemicellulose, bleaching and decoloring, concentrating, entering a saccharification fermentation and purification unit, and reacting with dilute fulvic acid black liquor, evaporating and concentrating, concentrated fulvic acid black liquor and distilled water to form an internal circulation system of fulvic acid production and cellulose purification. The production efficiency is improved, the energy is saved, and the integration degree of a production system is improved;

(6) provides a whole set of technical scheme and algorithm for the transfer treatment of the lactic acid sewage.

(7) Provides a systematic analysis method and a design method of polymer-grade polylactic acid for co-producing fulvic acid.

(8) Provides a set of integration and control methods for the operation of a polymer-grade lactic acid project for co-production of fulvic acid. The integration and control of the production system are realized through the control of each node which is mutually associated, and the cooperative operation of each industrial unit is kept.

(9) The technical scheme provided by the invention is also used for industrial production of the cellulosic ethanol.

(10) The preparation method is simple, convenient to operate, high in practicability and easy to popularize.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the invention and not to limit the invention.

FIG. 1 is a production system water circuit;

FIG. 2 is a CFU cell growth diagram, reflecting the degree of removal of toxic by-products;

FIG. 3 is a biochemical step of heterolactic fermentation of glucose and pentose sugars (xylose and arabinose).

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

First, the technical points or innovation points of the invention

1. The type and source of lactic acid impurities.

According to different reasons and sources of the lactic acid impurities, the problem is solved by starting from the lactic acid impurities, and the point of the problem is shifted from single post-treatment to prior + intermediate + post-treatment, and the post-treatment is purified by adopting a known process and treated by dividing into two parts and breaking each part.

First, the impurity species are determined. The impurities to be removed by purification in the lactic acid fermentation broth are mainly: lignin, formaldehyde, 5-hydroxymethylfurfural, acetic acid, pectin, melanin, methyl lactate, pyruvic acid, 2-hydroxybutyric acid, protein, mineral salt and the like.

The main sources are not limited to two aspects: the method is characterized in that the method is carried out by raw materials and is generated in the process of saccharification, fermentation and purification.

Regarding impurities brought by the raw materials:

the fiber material is composed of fiber components including cellulose, hemicellulose and lignin, and non-fiber components including pectin, wax, protein, fat and ash. The production of the cellulose polylactic acid mainly comprises the steps of saccharifying and hydrolyzing cellulose or cellulose and hemicellulose, then fermenting to produce lactic acid, and then purifying and polymerizing to obtain the polylactic acid. So that cellulose having a high degree of purification or cellulose and hemicellulose having a high degree of purification are obtained by pretreatment.

The technical scheme adopted in the invention is characterized in that the treatment measures for impurities brought by raw materials are as follows: firstly, separating and then carrying out deep treatment, namely, firstly, separating fiber raw materials to obtain high-purity cellulose and fulvic acid, and separating all non-cellulose components from the cellulose through pretreatment, namely, carrying out ammonium sulfite cooking and matched treatment to obtain high-purity purified cellulose, wherein the content of the cellulose components in the raw materials provided for subsequent saccharification and fermentation is 70-95%, and the content of the non-cellulose components is 30-5%; and simultaneously, all the separated non-cellulose components enter the yellow humic acid black liquor. The core component of the yellow humic acid black liquor is hydrolyzed sulfonated lignin, and other nutrient components are hydrolyzed hemicellulose monosaccharide and hydrolysate of non-fiber components pectin, wax, fat, protein and the like. And secondly, carrying out advanced treatment on the high-purity purified cellulose, and removing residual hemicellulose and saccharification fermentation inhibitors through the advanced treatment, namely detoxification and deep lignin and pigment removal.

Impurities generated during pretreatment include: impurities generated by hydrolysis of hemicellulose comprise weakly acidic inhibitors comprising formic acid, acetic acid, levulinic acid and the like and furfural inhibitors comprising furfural, 5-hydroxymethyl furfural and the like; impurities resulting from lignin hydrolysis, including phenolics, pigments, and unhydrolyzed lignin; impurities resulting from the degradation of non-fibrous components include hydrolysates of pectin, wax, fat, protein, etc.

Practice proves that weak acid inhibitors can be neutralized by alkaline water washing in the pretreatment link, other inhibitors can be effectively removed by water washing, and pigments can be removed by bleaching treatment.

Regarding impurities generated in the purification process of saccharification and fermentation:

firstly, carrying out saccharification hydrolysis fermentation, wherein residual lignin mixed in lactic acid hydrolysate is not hydrolyzed and is removed through solid-liquid separation;

secondly, formic acid, acetic acid, levulinic acid and the like generated by hydrolyzing residual hemicellulose are eliminated by an alkaline neutralizing agent, and common alkaline neutralizing agents comprise calcium hydroxide, calcium carbonate, sodium hydroxide, ammonia water and the like.

In particular, the wastewater generated by saccharification fermentation purification is completely mixed into the fulvic acid black liquor to produce fulvic acid, and the fulvic acid has strict limitation on Na ion content when being used for fertilizer production, so that the Na ion content is limited in the whole lactic acid saccharification fermentation purification process, and a Na-free alkaline agent is preferably used;

thirdly, control of inorganic salt composition. Various inorganic salts are added to the medium during fermentation, and commonly used inorganic salts include at least one of the following: such as mineral salts (e.g., mineral nitrogen, phosphates, sulfur, and trace elements such as zinc, magnesium, calcium, manganese, potassium, sodium, boron, iron, cobalt, copper, molybdenum, nickel, aluminum, etc.). Considering that all the sewage is to be pooled in fulvic acid as a fertilizer for crop production, in addition to limiting the use of sodium elements, mineral elements constituting trace element fertilizers are particularly preferred, elements that can be components of fertilizers and trace elements potassium, zinc, magnesium, manganese, potassium, boron, iron, copper, molybdenum;

fourthly, pyruvic acid is produced due to insufficient fermentation caused by excessive glucose, and the generation amount of pyruvic acid can be reduced by adjusting and controlling the using amount of a fermenting agent to match with the effective content of sugar liquor;

fifthly, decoloring.

2. The technical scheme for implementing the pretreatment by the ammonium sulfite method.

Firstly, cooking sulfonated and hydrolyzed lignin by an ammonium sulfite method to obtain fulvic acid, and hydrolyzing hemicellulose and non-cellulose components;

secondly, the separation of cellulose and non-cellulose components is realized by defibering and washing, and the purified high-purity cellulose and the fulvic acid dilute black liquor are obtained. The dilute fulvic acid black liquor is composed of all non-cellulose components except cellulose, including core components of sulfonated and hydrolyzed lignin, hydrolyzed hemicellulose, hydrolyzed pectin, wax, fat, protein and other non-cellulose components;

thirdly, the separated high-purity purified cellulose is used for producing lactic acid and polylactic acid according to the following technical route:

cellulose-hemicellulose deep hydrolysis-decoloration bleaching detoxification-dehydration-saccharification fermentation-lactic acid-purification-polylactic acid;

the separated fulvic acid is produced according to the following flow to obtain fulvic acid and distilled water: dilute fulvic acid black liquor, evaporation concentration, concentrated fulvic acid black liquor and distilled water, and the pH of the distilled water is 9-11 after denitrification treatment.

Fourthly, deep acid hydrolysis treatment is carried out on the hemicellulose remained in the purified cellulose obtained by cooking, and the impurity content of acetic acid in the lactic acid is reduced.

Fifthly, decoloring and bleaching. The color of the lactic acid is mainly derived from two aspects, namely, the color development group of the lignin and the color blackening of the fermentation liquor caused by residual acid and alkali treatment of the lactic acid fermentation protein. The chromophoric group of lignin enters the lactic acid fermentation liquor from two ways, namely the chromophoric group formed by pretreatment enters the lactic acid along with the cellulose substrate, and the pigment formed by mixing residual lignin in the lactic acid fermentation liquor. The decoloring method comprises the steps of bleaching purified cellulose and residual lignin in a pretreatment unit, preferably adopting hydrogen peroxide for alkaline bleaching, carrying out solid-liquid separation in a lactic acid fermentation liquor link, collecting solid lignin, returning the solid lignin to a pretreatment cooking unit to produce fulvic acid, and carrying out activated carbon decoloring on lactic acid.

Sixth, regarding detoxification of pre-treatment by-products, here we refer mainly to alkaline washing treatment of weak acids of hemicellulose production. On one hand, alkaline hydrogen peroxide bleaching can be adopted to eliminate weak acid impurities in degradation of hemicellulose, on the other hand, alkaline denitrified distilled water with pH of 9-11 is used for washing bleached cellulose, and superposition treatment is formed on the two aspects, so that removal of hemicellulose inhibitor can be guaranteed, and the practical effect is good.

3. Water circulation of the production system.

As shown in the water circulation of the production system in fig. 1, the water circulation of the whole production system has four interrelated parts:

the first is circulation of dilute fulvic acid black liquor. D, carrying out multi-effect evaporation and concentration on the dilute black liquor of the fulvic acid obtained by the defibering and separation of c to obtain a concentrated black liquor of the fulvic acid h and distilled water f, and carrying out powder spraying and drying on the concentrated black liquor of the fulvic acid to obtain commercial dry powder of the fulvic acid with high added value; the distilled water is subjected to known denitrification treatment to obtain g of denitrified distilled water with the pH value of 9-11.

And the second is the circulation of denitrified distilled water. And g, using the denitrified distilled water as n washing water in the m decolorizing and bleaching links, then collecting l washing water used for k hemicellulose, and reusing l washing water for c defibering and separating to finish a cycle.

Thirdly, the transfer treatment of the sewage after saccharification, fermentation and purification. The sewage generated by p saccharification and fermentation, q lactic acid purification and r polylactic acid is converged and transferred to a dispensing procedure a; g, supplementing the deficiency of the dispensing process in the step a by the denitrified distilled water according to the water balance condition of the whole system, and discharging the redundant part up to the standard; when the denitrified distilled water is not enough to make up the shortage of dosage, the denitrified distilled water is supplemented by clear water.

Fourthly, when the lactic acid is purified and concentrated by evaporation, distilled water can be used for regulating the concentration of the saccharified substrate. Generally, in the concentration step in the last step of pretreatment, the solid content of the purified fiber is 28-40%, the concentration of the saccharification substrate is generally 10-30%, and the solid content can be adjusted by adding an enzyme agent and distilled water.

4. And controlling the total sewage content of the production system.

The sewage of the production system is mainly generated in a pretreatment unit and a saccharification fermentation purification unit, and according to production practice analysis, the sewage of the pretreatment unit is completely collected into a treatment system of the fulvic acid black liquor, and the main contradiction is concentrated on the water quantity and the treatment mode of the saccharification fermentation purification unit.

The technical scheme adopted by the invention is as follows:

(1) controlling the amount of sewage generated by the saccharification, fermentation and purification unit;

(2) and transferring all sewage generated by saccharification, fermentation and purification to a pretreatment unit for treatment.

Two limitations of implementation of the embodiment are:

(1) the concentration of lactic acid that may be reached.

(2) The water consumption per ton of fulvic acid can be borne in production practice.

Firstly, the amount of sewage generated by the saccharification fermentation purification unit is controlled. The amount of the sewage generated by the saccharification fermentation purification unit depends on the concentration of the lactic acid, and theoretically, when the concentration of the lactic acid is X%, the amount of the sewage is Q1/X% -1. For example, when the concentration of lactic acid is 10%, the amount of sewage Q is 1/10% -1-9 tons per ton of lactic acid. When evaporation concentration is adopted for purification, distilled water is used for preparing a substrate, and the sewage to be treated is less than 9 tons per ton of lactic acid.

The concentration of the lactic acid depends on the concentration of the saccharification fermentation substrate, and if the cellulose saccharification rate is 90% and the efficiency of converting glucose into lactic acid is 80% according to the cellulose purity of 75%, the concentration of 10% of lactic acid needs the solid content of the saccharification substrate to be 18.52%; when the concentration of lactic acid is 10.8% in terms of the cellulose purity of 75%, the cellulose saccharification of 90%, the conversion efficiency of glucose into lactic acid of 80% and the solid content of the substrate of 20%, the amount of lactic acid wastewater theoretically becomes Q1/10.8% to 1/8.26 ton/ton of lactic acid.

Secondly, the water consumption per ton of fulvic acid can be tolerated in production practice.

The amount of sewage to be evaporated in the existing industrial production of the yellow humic acid dry powder is 8-12 tons/ton of yellow humic acid dry powder, on the premise that the effective content of the yellow humic acid is more than 40%, and the method has good economic benefit.

According to the calculation of the cellulose content of the fiber raw material of 33 percent, 3 tons of fulvic acid are produced when 1 ton of lactic acid is produced. Therefore, when 8.26 tons of lactic acid wastewater per ton of lactic acid correspond to: 8.26 tons of sewage/3 tons of fulvic acid dry powder are equivalent to 2.75 tons of sewage/ton of fulvic acid dry powder, and the total amount of the sewage to be evaporated is 5.75 tons/ton of fulvic acid according to the maximum water content of 3 tons of fulvic acid in consideration of steam break, medicament carrying water and raw material carrying water during the cooking pretreatment, which is far lower than the evaporation amount of 8-12 tons of sewage/fulvic acid dry powder which can be born by fulvic acid production.

According to this analysis, when the lactic acid concentration is as low as 4%, the amount of sewage corresponding to 24 ton/ton of lactic acid is obtained. According to the calculation of 1 ton of lactic acid associated with 3 tons of fulvic acid, 24/3 is equal to 8 tons of fulvic acid dry powder per ton of fulvic acid dry powder, and theoretically, the amount of lactic acid sewage to be shared and treated is within a tolerable range.

Therefore, the joint production of fulvic acid is enough to have enough sewage tolerance capacity for the industrial production of lactic acid.

In contrast, when 8.26 ton/ton of lactic acid is treated separately, especially when the sewage contains residual lignin and is not pretreated, the fiber raw material has more impurities and the pollution load is heavy, the sewage is difficult to treat, the sewage becomes the burden of industrial production of lactic acid, and the cellulose ethanol or cellulose lactic acid project can not be operated continuously seriously.

5. Sodium free adjuvant for the whole system.

The production of the polymer-grade cellulose lactic acid for co-producing the fulvic acid is compatible with the production of the fulvic acid and the lactic acid, the fulvic acid is mainly used for plant growth regulators and soil conditioners, has the effects of fixing nitrogen, dissolving phosphorus and dissolving potassium when being applied in combination with fertilizers, and is particularly suitable for being used as a water-soluble fertilizer for drip irrigation fertilization in saline-alkali arid areas, so that the Na ion content is strictly controlled, and the content of easily precipitated salt is controlled.

The technical scheme provided by the invention does not definitely limit the content of Na ions in relevant links of the whole production process, and mainly comprises the steps of adopting sodium-free cooking in a cooking link, adopting sodium-free bleaching in a pretreatment alkaline bleaching link, adopting sodium-free denitrification in a distilled water removal single treatment link, adopting sodium-free saccharification fermentation and purification in a lactic acid production link, and finally obtaining the sodium-free fulvic acid through the transmission of pretreatment fulvic acid black liquor and sewage.

6. Regarding the treatment of hemicellulose. Hemicellulose has positive and negative effects in the lactic acid production process according to C₅H₁₀0₅—C₃H₆0₃+CH₃COOH, theoretically hemicellulose can be converted by fermentation into lactic acid and acetic acid, 60% into lactic acid and 40% into acetic acid. On the one hand, the existence of the hemicellulose can improve the lactic acid yield of the fiber raw material, but also can generate a large amount of acetic acid and increase the content of impurities in the lactic acid. More importantly, the existence of the hemicellulose greatly reduces the saccharification efficiency of the hemicellulose and prolongs the saccharification time of the cellulose in practice; conversely, the saccharification efficiency of cellulose is significantly increased when the hemicellulose content is reduced. For analytical reasons, it should be that the presence of hemicellulose reduces the accessibility of cellulase to cellulose. On the other hand, hemicellulose is hydrolyzed through pretreatment, so that hemicellulose hydrolysis monosaccharide enters the fulvic acid black liquor, the yield of fulvic acid is improved, and the added value of fulvic acid is not lower than that of lactic acid. Therefore, the technical scheme adopted by the invention is to remove the hemicellulose in the pretreatment stage.

7. Lactic acid wastewater transfer treatment implementation scheme and algorithm.

The node elements involved in the transfer treatment of the lactic acid sewage mainly comprise the following elements: the sewage receiving node of the lactic acid sewage generation and control and pretreatment unit mainly comprises dosage, dilute black liquor of fulvic acid, concentrated black liquor of fulvic acid, pulp washing, direction of lactic acid concentrated distilled water, dosage cooking water consumption, pulp washing water consumption, cellulose solid content, total system sewage amount, evaporation water amount, distilled water generation amount, clear water amount supplement amount, cooking and pulp washing effects, water balance of a production system and the environment and the like. The lactic acid sewage transfer treatment scheme relates to the water balance problem of the whole production system for producing the polymer grade cellulose lactic acid with the joint production of fulvic acid, and relates to the layout planning and the integrated operation problem of the production system.

(1) And controlling the amount of the lactic acid sewage. The total amount of the sewage of the lactic acid waste liquid is 1/9-1-9 tons/ton of lactic acid according to the concentration of the lactic acid in the fermentation liquid of 10%. According to the conversion rate of glucose-lactic acid being 80%, the conversion rate of cellulose-glucose being 90%, and the concentration of saccharified substrate being 20%, the theoretical cellulose content must be greater than 69.4%. According to the technical scheme designed by the invention, the purity of the pretreated cellulose is 70-95%, and the concentration of lactic acid of 10% is fully guaranteed.

(2) And transferring the lactic acid wastewater to a receiving node for pretreatment unit treatment for optimization. The selectable sewage receiving nodes comprise four nodes of dispensing, dilute yellow humic acid black liquor, concentrated yellow humic acid black liquor and pulp washing, and different adding nodes can be selected according to different water qualities and water quantities:

adding from a dosage node. Can enter the cooking link to perform cooking hydrolysis, and can be directly used for preparing cooking liquor when the sewage pollution load is COD <50000 mg/L. The nutrient components in the sewage are mixed with the non-cellulose components obtained by cooking and hydrolysis. When the water volume is small, the water volume can be completely used for dispensing, and when the water volume is large and exceeds the dispensing requirement, other nodes are required to be added for processing;

② dilute black liquor is mixed. When the sewage pollution load is larger than COD100000 mg/L and the solid content is about 10%, the sewage can be directly mixed with the dilute fulvic acid black liquor to obtain the concentrated fulvic acid black liquor and distilled water through evaporation concentration treatment. The high-load sewage can be effectively treated by evaporation and concentration in the general industry. The sewage with the solid content of 10 percent and the COD of 100000-180000mg/L can be concentrated to the solid content of 50 percent by multi-effect evaporation, and then powder spraying and drying are carried out;

③ mixing the yellow humic acid thick black liquor. When the solid content of the transferred sewage reaches about 50 percent, the transferred sewage can be mixed with the thick fulvic acid black liquor to directly carry out powder spraying and drying to obtain the fulvic acid. Generally, lactic acid wastewater in production practice does not reach such a high pollution load;

and fourthly, the washing liquid is recycled. Three intervening nodes serving as washing water are arranged according to the required cleaning degree in sequence as follows: decolouring and bleaching, hemicellulose deep hydrolysis and four-stage reverse washing. Compared with distilled water, the pollution load of the lactic acid sewage is not easy to control, so the technical scheme of the invention does not claim that the lactic acid sewage is used for pulp washing treatment, particularly pulp washing of processes of decoloring bleaching and hemicellulose deep hydrolysis.

For the inlet water of the four-stage reverse washing IV-stage pulp squeezing, the comparative selection needs to be made according to the situation: comparing the pollution loads of lactic acid sewage and hemicellulose deep hydrolysis pulp washing water, wherein the person with the heavier pollution load enters the dilute fulvic acid black liquor, the person with the lighter pollution load enters a four-section reverse washing unit, and is discharged through a water outlet of a section I pulp extruder and converged into the dilute fulvic acid black liquor after the four-section reverse washing unit sequentially carries out IV-III-II-I reverse washing.

In a word, in the technical scheme of the invention, the lactic acid pulp washing sewage is preferentially used for a dosage node, and the redundant sewage directly enters the fulvic acid dilute black liquor or enters the four-section reverse washing unit according to the condition.

(3) Controlling the water consumption of the medicine preparation and the steaming. The set conditions are that the cellulose content of the raw material is 35 percent, the raw material consumes 4 absolute dry tons/ton of lactic acid, the solid-liquid ratio is 1:3, the steam consumes 4 tons/ton of lactic acid, the water content of the raw material is 15 percent, the water content of the medicament is 20 percent and 15 percent, the dewatering and pulp squeezing concentration is 40 percent, the pulp washing and diluting concentration is 15 percent, the purified cellulose yield is 1.4 tons/ton of lactic acid, the purified cellulose content is 80 percent, the evaporation residual solid content is 50 percent, the fulvic acid yield is 3 tons/ton of lactic acid, and the lactic acid sewage transfer treatment capacity is 9 tons/ton of lactic acid.

Then the process of the first step is carried out,

boiling water consumption: cooking liquor ratio of 1:3, namely the solid content is 25 percent, and the water consumption is 4 tons/25 percent and 16 tons/ton of lactic acid

Secondly, carrying water quantity on the material: 4 ton with water for raw material 15% + 4 ton with water for medicine 20% + 4 ton with water for steam 5.766 ton/ton lactic acid

Thirdly, dispensing and water replenishing: the water consumption for cooking is 16-5.766 with water amount which is 10.23 tons/ton of lactic acid

Transferring the amount of the sewage to be treated: 9 ton/ton lactic acid

The pretreatment unit needs water supplement amount: 10.234-9-1.23 ton/ton lactic acid

Sixthly, water supplement source: clean water or distilled water, preferably supplemented with distilled water.

(4) The amount of black liquor water is cooked. After cooking, defibering and pulp squeezing are carried out, the pulp squeezing concentration is 40 percent, and 1.4/80 percent of pulp is 1.75 ton/ton of lactic acid.

Then the process of the first step is carried out,

defibering, pulp squeezing and yellow humic acid black liquor extruding: 4/25% -1.75/40% ═ 11.63 ton/ton lactic acid

(5) The water consumption for washing the pulp. 1.75 tons of cellulose pulp, 15 percent of diluted pulp concentration and 40 percent of pulp squeezing concentration,

then the process of the first step is carried out,

water consumption for washing: 1.75/15% -1.75/40% ═ 7.34 ton/ton lactic acid

(6) The amount of sewage to be treated: the water amount of the black liquor is 11.63 percent, and the water amount for pulp washing is 7.34 to 18.97 tons per ton of lactic acid

(7) Amount of distilled water evaporated: calculated according to 2 tons of thick black liquor/ton of yellow humic acid dry powder,

obtaining the yield of distilled water: 8.97-2 x 3-12.97 ton/ton lactic acid

(8) The pretreatment unit is rich in distilled water. Preferably, the distilled water surplus of the pretreatment unit is as follows: the yield of distilled water is 12.97, the amount of water supplement for medicine is 1.23, and the water consumption for washing pulp is 7.34 which is 4.4 tons/ton of lactic acid.

(9) Distilled water is used for the water quantity of the saccharification and fermentation unit. Preferably, the solid content of the pretreated cellulose pulp is 40 percent, the solid content of the saccharified substrate is 20 percent, enzyme agent liquid is added according to the amount of 10 percent, the rest is supplemented by distilled water, and the lactic acid fermentation liquid wastewater is completely transferred to a pretreatment unit for treatment,

the saccharification and fermentation unit then requires additional amounts of distilled water: (1.75/20% -1.75/40%) -1.75 × 10% ═ 4.27 tons per ton of lactic acid.

(10) Distilled water requiring outward discharge: 4.4-4.27-0.13 ton/ton lactic acid.

In summary, the distilled water produced by the pretreatment unit goes to: (1) 1.23 ton/ton of ethanol is supplemented and dispensed, (2) 7.34 ton/ton of lactic acid is supplemented and pulp washing, (3) 4.27 ton/ton of lactic acid is supplemented and saccharification and fermentation is supplemented, and (4) 0.13 ton/ton of lactic acid is discharged.

8. The technical scheme and the method disclosed by the invention are also suitable for industrial production of the cellulosic ethanol.

Second, technical scheme

The industrial production system and method of the polymer grade cellulose lactic acid for co-producing fulvic acid preferably extend the purification range to a pretreatment unit and a saccharification fermentation purification unit for pre-neutralization and post-treatment; separating the fiber material by pretreatment to obtain purified cellulose and fulvic acid, producing lactic acid from the purified cellulose component, and producing fulvic acid from all non-cellulose components such as separated lignin; the method comprises the following steps of (1) carrying out transfer treatment on lactic acid waste liquid sewage to finally obtain fulvic acid with high added value and high-purity polymer grade cellulose lactic acid:

(1) purifying cellulose and fulvic acid by pretreatment and separation, removing impurities in lactic acid carried by raw materials, including lignin and phenolic substances hydrolyzed by the lignin, aldehydes and organic acids generated by hemicellulose hydrolysis, and protein, pectin and wax fat generated by non-cellulose components, and decolorizing;

(2) controlling and removing impurities in the saccharification liquid; including lignin and non-saccharified hemicellulose;

(3) controlling and removing impurities formed by intermediate byproducts generated in the fermentation production process, including inorganic salt and acetic acid, and impurities formed by nutrient solution not consumed in the fermentation process, including pyruvic acid and the like;

(4) decoloring;

(5) concentrating and dehydrating lactic acid, and performing classified treatment and recycling on the generated sewage;

(6) limiting the dosage of Na ions in the pretreatment and saccharification fermentation purification processes;

(7) the integrated production system and water circulating system includes pre-treated water circulation, fulvic acid black liquor circulation treatment and lactic acid waste liquor sewage transfer treatment.

Finally, purified polymer-grade lactic acid and fulvic acid are obtained. The method specifically comprises the following steps:

in some embodiments, the high purity purified cellulose and fulvic acid are separated by pretreatment to remove impurities carried into the lactic acid by the starting material, in two steps:

firstly, pretreatment and separation are carried out to obtain high-purity purified cellulose and fulvic acid.

The impurities brought into the lactic acid by the raw materials comprise lignin, phenolic substances hydrolyzed by the lignin, hemicellulose and organic mixed acid hydrolyzed by the hemicellulose, including acetic acid, furfural, hydroxymethyl furfural, formic acid, levulinic acid and protein, pigment, pectin and wax fat generated by hydrolysis of non-fibrous components;

the high-purity purified cellulose is characterized in that:

the content of cellulose components is 70-95%, preferably 75-95%, and the content of non-cellulose components is 30-5%, preferably 10-5%.

The non-cellulosic components include cellulosic components other than cellulose and non-cellulosic components in the fibrous material.

The non-cellulose components except cellulose comprise lignin and hemicellulose, wherein the content of the hemicellulose is 2-10 percent, and the content of the lignin is 2-10 percent;

the non-cellulose components in the fiber raw material comprise pectin, wax and crude protein, and the content of the non-cellulose components is 0-5%;

the phenolic substance is a phenolic substance which is generated by hydrolysis of lignin and is rich in hydroxyl, and the content of the phenolic substance is 0-0.1%;

the organic heteropolyacid and other inhibitors are generated by hydrolyzing hemicellulose, and comprise methanol, furfural, 5-hydroxymethyl furfural, acetic acid and 2-hydroxybutyric acid, and the content of the organic heteropolyacid and the other inhibitors is 0-0.3%.

The pretreatment process comprises the following steps: by ammonium sulfite cooking, sulfonation hydrolysis of lignin, hydrolysis of hemicellulose, hydrolysis of pectin, wax and protein, and then separation of cellulose and all non-cellulose components except cellulose by defibering and washing.

And secondly, performing advanced treatment on the cellulose, including acidification treatment for deeply hydrolyzing hemicellulose, deeply delignifying, decoloring and deeply detoxifying on the cellulose pulp obtained in the first step.

In some embodiments, the polymer grade cellulose lactic acid factory production system and method for co-producing fulvic acid separate cellulose and all non-cellulose components by cooking, defibering and washing, specifically, a, cooking by an ammonium sulfite method to obtain cooked cellulose pulp, b, squeezing pulp and pulping defibering, collecting to obtain fulvic acid cooked thin black liquor, c, performing multi-section, preferably four-section reverse washing pulp washing on the pulp subjected to b defibering, separating fiber pulp and black liquor, collecting to obtain fulvic acid washed thin black liquor and cellulose pulp, d, collecting and mixing the cooked thin black liquor and the washed thin black liquor, sending the mixture to an evaporation station for evaporation and concentration, and obtaining fulvic acid concentrated black liquor and distilled water. And (3) spraying and drying the thick yellow humic acid black liquor to obtain yellow humic acid dry powder, and washing cellulose pulp by using distilled water with the pH value of 7-9 after known salt control denitrification treatment.

In some embodiments, a polymer-grade cellulose lactic acid industrial production system and method for co-producing fulvic acid are used for acidifying cellulose and deeply hydrolyzing residual hemicellulose, and specifically, the method comprises the steps of adding 1-3% of acid, concentrating slurry by 28-40%, mixing by a high-concentration mixer, feeding into a reaction bin, keeping the temperature at 80-95 ℃ for 60-120 min, washing the slurry, collecting the washing water, and using the washing water for four-stage reverse washing and pulp washing in the previous process. So that 1-4%, preferably 2-3% of hemicellulose remains.

The pulp washing refers to the pulp washing of denitrified distilled water obtained by evaporating and concentrating the dilute fulvic acid black liquor or sewage generated in the subsequent decoloring and bleaching process.

The acid is selected from one or a mixture of inorganic acid, organic acid, amino acid and mineral acid, and preferably phosphoric acid, sulfuric acid and hydrochloric acid.

In some embodiments, a system and method for the industrial production of lactic acid from polymer grade cellulose with co-production of fulvic acid, and a third step of deep delignification, decolorization, and deep detoxification of cellulose. The deep delignification is carried out by adopting a conventional method in pulping production, and oxygen delignification is preferred; the decolorization is carried out by a conventional method in pulping production, hydrogen peroxide bleaching is preferred, and a pH regulator is a sodium-free alkaline agent. The lignin content is 1-4%, preferably 2-3%, and the fiber pulp whiteness is 75-90% ISO.

The detoxification refers to the process of washing and removing the residual heteroacid such as acetic acid, 2-hydroxybutyric acid and the like in the cellulose by using alkaline denitrified distilled water.

The sodium-free alkali agent, preferably magnesium alkali, namely at least one of MgO, Mg (OH)2, MgCO3 and Mg (HCO3)2, ammonia water and KOH, and NaOH is limited.

In some embodiments, the industrial production system and method for producing the polymer-grade cellulose lactic acid with fulvic acid coproduction adopts an ammonium sulfite method for cooking, specifically, the dosage of ammonium sulfite is 10-25%, the pH is adjusted to 4-10 by using acid and a sodium-free alkali agent, and the liquid ratio is 1: 2.5-4 ℃, the temperature is 140-175 ℃, preferably 140-160 ℃, and the temperature is kept for 60-180 min, preferably 90-120 min.

The acid is one or a mixture of sulfuric acid, hydrochloric acid and phosphoric acid, and the dosage is 1-5%;

the sodium-free alkali agent comprises magnesium alkali, namely ammonia water and KOH, wherein the ammonia water and the KOH are added in an amount of 1-7%, and the use amount of the magnesium alkali is limited, namely at least one of MgO, Mg (OH)2, MgCO3 and Mg (HCO3) 2.

In some embodiments, the industrial production system and method for the co-production of fulvic acid and the polymer-grade cellulose lactic acid are used for removing impurities formed by intermediate byproducts generated by saccharification, fermentation and purification and decoloring by adopting a known method. Firstly, adopting a sodium-free neutralizer, namely limiting the dosage of sodium ion salts in the saccharification fermentation process, namely adopting a sodium-free alkaline neutralizer and adding additional sodium-free mineral nutrients; secondly, performing solid-liquid separation on lactic acid liquid obtained by saccharification or simultaneous fermentation of saccharification, collecting and adding undegraded residual lignin to a pretreatment cooking part to produce fulvic acid, and thirdly, performing solid-liquid separation on calcium sulfate and magnesium sulfate precipitates generated by separating lactic acid and lactate to perform harmless treatment. A purified lactic acid liquid is obtained.

The sodium-free basic neutralizing agent includes Ca (OH)2, CaO, MgOH, KOH, aqueous ammonia, and urea.

The additional sodium-free nutrient may be selected from at least one of: for example mineral salts (e.g. mineral nitrogen, phosphates, sulphur and trace elements such as zinc, magnesium, calcium, manganese, potassium, boron, iron, cobalt, copper, molybdenum, nickel, aluminium, etc.), in particular the mineral elements constituting the trace element fertilizer, preferably the elements that can be used as fertilizer components and the trace elements potassium, zinc, magnesium, manganese, potassium, boron, iron, copper, molybdenum.

The collection of the undegraded residual lignin refers to that when saccharification and fermentation are carried out step by step, the saccharification liquid is subjected to solid-liquid separation after saccharification; when saccharification and fermentation are carried out synchronously, solid-liquid separation is carried out on the lactic acid fermentation liquor after saccharification and fermentation are carried out simultaneously.

The known methods for extracting lactic acid from lactic acid fermentation broth include, but are not limited to, calcium salt method, extraction method, adsorption method, membrane method, molecular distillation method, and distillation under reduced pressure.

In some embodiments, the industrial production system and method for polymer grade cellulose lactic acid with fulvic acid co-production, total amount control and transfer treatment of lactic acid wastewater, the specific embodiment is as follows:

③ mixing the yellow humic acid thick black liquor. When the solid content of the transferred sewage reaches about 50%, the transferred sewage can be mixed with the yellow fulvic acid thick black liquor to directly carry out powder spraying and drying to obtain the fulvic acid. Generally, lactic acid wastewater in production practice does not reach such a high pollution load;

(3) Controlling the water consumption of the medicine preparation and the steaming. The set conditions are that the cellulose content of the raw material is 35 percent, the raw material consumes 4 absolute dry tons/ton of lactic acid, the solid-liquid ratio is 1:3, the steam consumes 4 tons/ton of lactic acid, the water content of the raw material is 15 percent, the water content of the medicament is 20 percent and 15 percent, the dewatering pulp squeezing concentration is 40 percent, the pulp washing dilution concentration is 15 percent, the purified cellulose yield is 1.4 tons/ton of lactic acid, the cellulose content after the purification pretreatment is 80 percent, the solid content of the yellow rot concentrated black liquor is 50 percent, the yellow rot acid yield is 3 tons/ton of lactic acid, and the lactic acid sewage transfer treatment capacity is 9 tons/ton of lactic acid.

Then the process of the first step is carried out,

② water consumption in cooking: cooking liquor ratio of 1:3, namely the solid content is 25 percent, and the water consumption is 4 tons/25 percent and 16 tons/ton of lactic acid

Secondly, carrying water quantity on the material: 4 ton with water for raw material 15% + 4 ton with water for medicine 20% + 15% + 4 ton with water for steam 5.766 ton/ton lactic acid

Transferring the amount of the sewage to be treated: 9 ton/ton lactic acid

The pretreatment unit needs water supplement amount: 10.234-9 ═ 1.23 ton/ton of lactic acid

Then the process of the first step is carried out,

then the process of the first step is carried out,

water consumption for washing: 1.75/15% -1.75/40% ═ 7.34 ton/ton lactic acid

obtaining the yield of distilled water: 8.97-2 x 3-12.97 ton/ton lactic acid

Finally, the distilled water produced by the pretreatment unit goes to: (1) 1.23 ton/ton of ethanol is supplemented and dispensed, (2) 7.34 ton/ton of lactic acid is supplemented and pulp washing, (3) 4.27 ton/ton of lactic acid is supplemented and saccharification and fermentation is supplemented, and (4) 0.13 ton/ton of lactic acid is discharged.

In some embodiments, a system and method for the industrial production of polymer grade cellulose lactic acid with co-production of fulvic acid provides a technical scheme and a method system for a system for separating all fiber raw materials into cellulose components and non-cellulose components, producing lactic acid from the cellulose components, producing fulvic acid from all non-cellulose components such as separated lignin and the like. The fiber raw materials comprise various wood fibers, non-wood plant fibers, various crop straws, wastes and residues and wastes of industrial processing, and specifically comprise: wheat and barley straws and wheat bran, corn straws and corncobs and industrial residues, rice and rice chaff, cotton straws and cotton boll hulls, bean straws, rape stalks, peanut hulls, various tree twigs and offcuts, reeds, bamboos, bagasse, wattle, palm shells and the like.

The technical scheme and the method disclosed by the invention are also suitable for industrial production of the cellulosic ethanol.

The present invention is described in further detail below with reference to specific examples, which are intended to be illustrative of the invention and not limiting.

In the following examples, the penetrant JFC refers to: fatty alcohol polyoxyethylene ether.

The fermentation strains are all commercial strains, and other raw materials are all commercial products.

Example 1

Firstly, preparing materials. Removing impurities from wheat straw, and cutting into 2-5 cm;

and step two, dispensing. 20% of ammonium sulfite, 1:3, penetrant JFC 0.1%, sulfuric acid 1%, pH 6;

and thirdly, cooking and hydrolyzing. The temperature is 165 ℃, the temperature is kept for 120min, and the pH value is 4.5. Hydrolyzing lignin, hydrolyzing hemicellulose, and hydrolyzing non-cellulose components including pectin, wax, fat, and protein by cooking sulfonation;

and fourthly, untwining. Hydrolyzing and pulping by a high-concentration pulping machine to strip cellulose and non-cellulose components and release hydrolyzed substances in fiber gaps;

and fifthly, squeezing and washing pulp. The pulp is concentrated by 30 percent through double-helix pulp extrusion. Collecting pulp squeezing black liquor; washing pulp, and separating cellulose and non-cellulose components by adopting 4 sections of reverse washing. The first, second, third and fourth roll press are installed from press to back, the washing water is injected from the inlet of the fourth press, from the outlet of the fourth press to the inlet of the third press, from the outlet of the third press to the inlet of the second press, from the outlet of the second press to the inlet of the first press, from the outlet of the first press to the black liquor collected by the double screw press, the fulvic acid thin night and purified cellulose pulp are obtained. The pulp was found to have a cellulose content of 65%, a hemicellulose content of 17%, and a lignin content of 18%.

The treatment is carried out according to the respective treatment flows of cellulose and the dilute black fulvic acid liquor.

And sixthly, evaporating and concentrating the dilute fulvic acid black liquor. Evaporating to obtain a fulvic acid concentrated black liquor and distilled water;

seventhly, performing powder spraying and drying on the strong yellow humic acid black liquor to obtain yellow humic acid dry powder, wherein the content of a yellow humic acid dry base is 43% by testing;

eighthly, performing salt control denitrification on the distilled water to obtain denitrified distilled water with the pH value of 9-11;

and step nine, performing advanced treatment on the slurry to deeply remove hemicellulose. Namely, the cellulose pulp obtained by four sections of reverse washing is acidified to deeply hydrolyze residual hemicellulose. Firstly, adding 3% of phosphoric acid, concentrating the pulp by 28-40%, mixing by a high-concentration mixer, putting the mixture into a reaction bin, keeping the temperature at 80-95 ℃ for 120min, then washing the pulp by using the washing water generated in the next bleaching and decoloring procedure, squeezing the pulp, and collecting the washing water for reversely washing and washing the pulp in the four sections of the previous procedure. Measuring the cellulose content to be 73 percent, the hemicellulose content to be 9 percent, the lignin content to be 18 percent and the whiteness to be 48 percent;

and step ten, decoloring, bleaching and detoxifying. The decolorization is carried out by adopting a conventional method in pulping production, preferably hydrogen peroxide bleaching, wherein a pH regulator uses a sodium-free alkaline agent, the using amount of KOH is 3 percent, the initial pH value is 13, the ending pH value is 9, hydrogen peroxide is 3 percent, the using amount of a chelating agent EDTA is 0.1 percent, polyacrylamide is 0.01 percent, pulp concentration is 30 percent, the temperature is 90 ℃, heat preservation is carried out for 90min, denitrified distilled water is used for washing pulp, and the pulp washing water is used for pulp washing and pulp squeezing in the previous process hemicellulose deep hydrolysis process, and the concentration is 32. The whiteness is 73% ISO, the cellulose content is 75%, the hemicellulose content is 9%, and the lignin content is 16%;

step ten, adopting conventional synchronous diastatic fermentation for diastatic fermentation, adopting a known process, preferably, adding 10FPU/g of cellulase, 10% of Rhizopus oryzae inoculum size, at 30 ℃, pH5.5, and 48h to obtain lactic acid fermentation liquor;

the twelfth step, lactic acid purification. The sodium-free lactic acid purification is carried out according to the known method to achieve the polymer grade lactic acid.

Thirteenth, polylactic acid is produced according to a known method.

And fourteenth, sewage transfer treatment. And (4) measuring and calculating the sewage quantity, wherein the produced fermentation wastewater is completely transferred to a pretreatment dosage link according to the lactic acid extraction concentration of 99.6%, and redundant sewage is directly mixed into the dilute black liquor for evaporation and concentration and is recycled after denitrification.

Example 2

Firstly, preparing materials. Removing impurities from cotton straw, and cutting into 2-5 cm;

and step two, dispensing. 20% of ammonium sulfite, 1:3, penetrant JFC 0.1%, KOH 3%, pH13,

and thirdly, cooking and hydrolyzing. Keeping the temperature at 170 ℃ for 150min, and finishing the cooking with pH 8. Hydrolyzing lignin by cooking sulfonation, hydrolyzing hemicellulose, and hydrolyzing non-cellulosic components including pectin, wax, fat, and protein;

and fifthly, squeezing and washing pulp. The pulp is concentrated by 30 percent through double-helix pulp extrusion. Collecting pulp squeezing black liquor; washing pulp, and separating cellulose and non-cellulose components by adopting 4 sections of reverse washing. The first, second, third and fourth roll press are installed from press to back, the washing water is injected from the inlet of the fourth press, from the outlet of the fourth press to the inlet of the third press, from the outlet of the third press to the inlet of the second press, from the outlet of the second press to the inlet of the first press, from the outlet of the first press to the black liquor collected by the double screw press, the fulvic acid thin night and purified cellulose pulp are obtained. Measuring the cellulose content of the pulp to be 72%, the hemicellulose content to be 18% and the lignin content to be 10%;

and step nine, performing advanced treatment on the slurry to deeply remove hemicellulose. Namely, the cellulose pulp obtained by four sections of reverse washing is acidified to deeply hydrolyze residual hemicellulose. Firstly, adding 3% of phosphoric acid, concentrating the pulp by 28-40%, mixing by a high-concentration mixer, entering a reaction bin, keeping the temperature at 80-95 ℃ for 120min, then washing and squeezing the pulp by using the washing water generated in the next bleaching and decoloring process, and collecting the washing water for reverse washing and washing of four sections of the previous process. Measuring the cellulose content to be 82 percent, the hemicellulose content to be 10 percent, the lignin content to be 8 percent and the whiteness to be 46 percent;

and step ten, decoloring, bleaching and detoxifying. The decolorization is carried out by adopting a conventional method in pulping production, preferably hydrogen peroxide bleaching, wherein a pH regulator uses a sodium-free alkaline agent, the using amount of KOH is 3 percent, the initial pH value is 12, the ending pH value is 9, hydrogen peroxide is 3 percent, the using amount of a chelating agent EDTA is 0.1 percent, polyacrylamide is 0.01 percent, pulp concentration is 30 percent, the temperature is 85 ℃, heat preservation is carried out for 120min, denitrified distilled water is used for washing pulp, and the pulp washing water is used for washing pulp and squeezing pulp in the process of deeply hydrolyzing hemicellulose in the process, and the concentration is. The whiteness is 73% ISO, the cellulose content is 84%, the hemicellulose content is 9%, and the lignin content is 7%;

step ten, adopting conventional synchronous diastatic fermentation for diastatic fermentation, adopting a known process, preferably, adding 10FPU/g of cellulase, 10% of Rhizopus oryzae inoculum size, at 30 ℃, pH5.5, and for 72h to obtain lactic acid fermentation liquor;

the twelfth step, lactic acid purification. Sodium-free lactic acid purification is carried out according to a known method to obtain polymer-grade lactic acid.

Thirteenth, polylactic acid is produced according to a known method.

Example 3

Water circulation embodiment of production system:

Fourthly, when the lactic acid is purified and concentrated by evaporation, distilled water can be used for regulating the concentration of the saccharified substrate. Generally, in the last step of the pre-treatment, the concentration of the purified fiber is 28-40%, the concentration of the saccharification substrate is generally 10-30%, and the solid content can be adjusted by adding an enzyme and distilled water.

Example 4

Detoxification embodiment-three detoxification treatments are carried out on heteropolyacids such as hemicellulose acetic acid:

firstly, cooking and hydrolyzing;

secondly, defibering, washing and separating;

thirdly, evaporating and concentrating to obtain distilled water;

fourthly, denitrifying to obtain alkaline denitrified distilled water with the pH value of 9-11;

the first to fourth steps above were operated according to example 1 and example 2.

Fifthly, removing hemicellulose acetic acid and the like for three times. Washing the cellulose pulp in the bleaching process by using alkaline denitrified distilled water to obtain washing pulp water with the pH value of 8-11, wherein the washing pulp water is used for washing after the hemicellulose in the front-stage process is deeply hydrolyzed;

sixthly, performing secondary detoxification on hemicellulose acetic acid and the like. Bleaching cellulose under the condition of pH 11-13, and simultaneously completing neutralization of hemicellulose acetic acid and the like, wherein the pH of cellulose pulp is 9-11 after bleaching;

seventhly, performing first detoxification on the hemicellulose acetic acid. After the hemicellulose is subjected to deep acidic hydrolysis, washing pulp by using washing pulp generated in a subsequent bleaching process to complete first detoxification. Obtaining the pH value of the washing slurry of 7-9;

and eighthly, the pulp washing sewage formed by detoxification is used for hemicellulose hydrolysis pulp washing, the hemicellulose hydrolysis pulp washing water sewage enters a four-section reverse washing unit of a separation pulp washing procedure, is added from a water injection port of a pulp squeezing machine at the IV section, sequentially passes through the IV-III-II-I fourth section to a thin pulp machine for reverse washing, and finally is collected from an outlet of the pulp washing machine at the I section to obtain the fulvic acid thin black liquor, and enters an evaporation concentration procedure.

In summary, the detoxification sequence was:

first detoxification: deeply hydrolyzing hemicellulose and washing pulp;

and (3) second detoxification: alkaline decoloring and bleaching;

third detoxification: after alkaline bleaching, the pulp is washed with alkaline nitrogen distilled water.

Example 5

Comparative example-detoxification effect experiment-influence of detoxification on saccharification and fermentation of cellulose ethanol:

the first step is as follows: and (4) pretreating and preparing materials. Wheat straw is used as a raw material, and is subjected to cooking pretreatment by pulping with a neutral ammonium sulfite method to obtain a slurry a; and then, acidizing the slurry a to obtain slurry b. The acidification treatment process comprises the following steps: hydrochloric acid 2%, pulp concentration 8%, cooking temperature 95-100 deg.C, time 90min, washing with water three times, pH 7.

Sampling 5 kg of slurry b, measuring the solid content to be 35%, and measuring the fiber component: cellulose 64%, hemicellulose 18%, lignin and ash 18%.

Step two, enzymolysis saccharification: the cellulase is Novoxil CTec2.0, the dosage is 4mg of zymoprotein/g of dry base material, enzymolysis and saccharification are carried out for 36 hours at 50 ℃, and 72.2g/L glucose and 19.0g/L xylose are obtained.

Step three, fermentation: fermenting with original raw materials without any dilution and drying. The fermentation mode is synchronous saccharification and glucose/xylose co-fermentation. 20 percent of solid content, a 5L fermentation tank, 30 ℃, and 10 percent of inoculation amount, wherein the fermentation strain is saccharomyces cerevisiae engineering bacteria.

Fermentation time: data were measured every 12 hours for 96 hours.

The concentration of the fermentation ethanol is 40.3g/L, and the reduced volume concentration is 5.1%. The yield of ethanol from cellulose and hemicellulose in the cotton stalk material was 48.6% of theoretical.

Fourthly, analyzing the detection data:

(one) sugar-alcohol conversion

Fermenting for 96 hours:

glucose content: 1g/L, sugar-alcohol conversion 98.9%

Xylan content: 4g/L, saccharification rate 78.9%

Ethanol content: 40.3g/L

Finally, the yield of the fermented ethanol is 40.3g/L, and the reduced volume concentration is 5.1%.

(II) toxic by-product Effect

In this example, no conventional inhibitor was detected, indicating that the pretreatment of the fiber material had a good detoxifying effect. FIG. 2CFU cell growth diagram

FIG. 2 shows the cell viability of sugar-alcohol converting fermentation enzymes, indicating that the yeast is not affected by toxic by-products.

Example 6

The decolorization embodiment:

in the first step, sulfonated and hydrolyzed lignin is cooked. Generating black lignin hydrolysate;

and secondly, defibering, washing and separating to obtain purified cellulose and melanin lignin hydrolysate, namely the yellow humic acid black liquor. Purifying cellulose with the content of residual lignin of 3-8%, preferably 3-5%;

and thirdly, decoloring and bleaching. The decolorization is carried out by adopting a conventional method in pulping production, preferably hydrogen peroxide bleaching, wherein a pH regulator uses a sodium-free alkaline agent, the using amount of KOH is 3%, the initial pH value is 12, the ending pH value is 9, hydrogen peroxide is 3%, the using amount of a chelating agent EDTA is 0.1%, polyacrylamide is 0.01%, pulp concentration is 30%, the temperature is 90 ℃, heat preservation is carried out for 90min, denitrified distilled water is used for washing pulp, and the pulp washing water is used for washing pulp and squeezing pulp in the process of deeply hydrolyzing hemicellulose in the process, and the concentration is 32%. The whiteness degree is 75% ISO, the cellulose content is 85%, the hemicellulose content is 8%, and the lignin content is 7%;

fourthly, collecting solid lignin in the lactic acid fermentation liquor, reusing the solid lignin in a pretreatment cooking link, and continuing sulfonation and hydrolysis to produce fulvic acid;

fifthly, lactic acid decolorization. The pigment source in the lactic acid is brought by cellulose, and the protein in the fermentation substrate is generated by repeated acid and alkali treatment and is removed by activated carbon adsorption.

Example 7

The lactic acid fermentation liquor sewage transfer treatment embodiment:

the node elements involved in the transfer treatment of the lactic acid sewage mainly comprise the following elements: (1) the production and control of lactic acid sewage, (2) sewage receiving node of pretreatment unit, mainly including dispensing, direction of fulvic acid dilute night, fulvic acid concentrated black liquor, pulp washing and lactic acid concentrated distilled water, (3) dispensing boiling water consumption, (4) pulp washing water consumption, (5) cellulose solid content, (6) system sewage total amount, (7) evaporation water amount, (8) distilled water production amount, (9) clear water amount supplement amount, (10) boiling and pulp washing effect, (11) production system and environment water balance, etc.

1. And controlling the amount of the lactic acid sewage. The total amount of the sewage of the lactic acid waste liquid is 1/9-1-9 tons/ton of lactic acid according to the concentration of the lactic acid fermentation liquid of 10%. According to the conversion rate of glucose-lactic acid being 80%, the conversion rate of cellulose-glucose being 90%, and the concentration of saccharified substrate being 20%, the theoretical cellulose content must be greater than 69.4%. According to the technical scheme designed by the invention, the purity of the pretreated cellulose is 70-95%, and the concentration of lactic acid of 10% is fully guaranteed.

2. And transferring the lactic acid wastewater to a receiving node for pretreatment unit treatment for optimization. The selectable sewage receiving nodes comprise four nodes of dispensing, dilute yellow humic acid black liquor, concentrated yellow humic acid black liquor and pulp washing, and different adding nodes can be selected according to different water qualities and water quantities:

(1) adding from the dosage node. Can enter the cooking link to perform cooking hydrolysis, and can be directly used for preparing cooking liquor when the sewage pollution load is COD <50000 mg/L. The nutrient components in the sewage are mixed with the non-cellulose components obtained by cooking and hydrolysis. When the water volume is small, the water volume can be completely used for dispensing, and when the water volume is large and exceeds the dispensing requirement, other nodes need to be selected for processing;

(2) the diluted black liquor is mixed in. When the sewage pollution load is larger than COD100000 mg/L and the solid content is about 10%, the sewage can be directly mixed with the dilute fulvic acid black liquor to obtain the concentrated fulvic acid black liquor and distilled water through evaporation concentration treatment. The high-load sewage can be effectively treated by evaporation and concentration in the general industry for the high-pollution load sewage. The sewage with the solid content of 10 percent and the COD of 100000-180000mg/L can be concentrated to the solid content of 50 percent by multi-effect evaporation, and then powder spraying and drying are carried out;

(3) mixing with the concentrated black liquor of fulvic acid. When the solid content of the sewage reaches about 50 percent, the sewage can be mixed with the yellow fulvic acid thick black liquor to directly carry out powder spraying and drying to obtain the fulvic acid. Generally, lactic acid wastewater in production practice does not reach such a high pollution load;

(4) can be recycled as washing water. The three intervening nodes of the washing water are arranged in sequence according to the required cleaning degree: decolouring and bleaching, hemicellulose deep hydrolysis and four-stage reverse washing. Compared with distilled water, the pollution load of the lactic acid sewage is not easy to control, so the technical scheme of the invention does not claim that the lactic acid sewage is used for pulp washing treatment, particularly pulp washing in processes of decoloring, bleaching and hemicellulose deep hydrolysis.

For the inlet water of the four-stage reverse washing IV-stage pulp squeezing, the comparative selection needs to be made according to the situation:

comparing the pollution loads of lactic acid sewage and hemicellulose deep hydrolysis pulp washing water, wherein the person with the heavier pollution load enters the dilute fulvic acid black liquor, the person with the lighter pollution load enters a four-section reverse washing unit, and is discharged into the dilute fulvic acid black liquor through a water outlet of a section I pulp extruder after sequentially performing IV-III-II-I reverse washing.

In a word, in the technical scheme of the invention, the lactic acid pulp washing sewage is preferentially used for a dosage node, and the redundant sewage directly enters the yellow humic acid washing black liquor or enters the four-section reverse washing unit according to the condition.

3. Controlling the water consumption of the medicine preparation and the steaming. The set conditions are that the cellulose content of the raw material is 35 percent, the raw material consumes 4 absolute dry tons/ton of lactic acid, the solid-liquid ratio is 1:3, the steam consumes 4 tons/ton of lactic acid, the water content of the raw material is 15 percent, the medicament dosage is 20 percent, the water content is 15 percent, the concentration of dewatering and pulp squeezing is 40 percent, the concentration of pulp washing and dilution is 15 percent, the yield of purified cellulose is 1.4 tons/ton of lactic acid, the cellulose content after purification is 80 percent, the solid content of evaporation residue is 50 percent, the yield of fulvic acid is 3 tons/ton of lactic acid, and the transfer treatment capacity of lactic acid sewage.

Then the process of the first step is carried out,

Transferring the amount of the sewage to be treated: 9 ton/ton lactic acid

4. The amount of black liquor water is cooked. And (3) defibering and squeezing pulp after cooking, wherein the concentration of the squeezed pulp is 40%, and the pulp is obtained, wherein 1.4/80% of the pulp is 1.75 ton/ton of lactic acid.

Then the process of the first step is carried out,

5. The water consumption for washing the pulp. 1.75 tons of cellulose pulp, 15 percent of diluted pulp concentration and 40 percent of pulp squeezing concentration,

then the process of the first step is carried out,

water consumption for washing: 1.75/15% -1.75/40% ═ 7.34 ton/ton lactic acid

6. The amount of sewage to be treated: the water amount of the black liquor is 11.63 percent, and the water amount for pulp washing is 7.34 to 18.97 tons per ton of lactic acid

7. Amount of distilled water evaporated: calculated according to 2 tons of thick black liquor/ton of yellow humic acid dry powder,

obtaining the yield of distilled water: 8.97-2 x 3-12.97 ton/ton lactic acid

8. The pretreatment unit is rich in distilled water. Preferably, the distilled water surplus of the pretreatment unit is as follows: the yield of distilled water is 12.97, the amount of water supplement for medicine is 1.23, and the water consumption for washing pulp is 7.34 which is 4.4 tons/ton of lactic acid.

9. Distilled water is used for the water quantity of the saccharification and fermentation unit. Preferably, the solid content of the pretreated cellulose pulp is 40 percent, the solid content of the saccharification substrate is 20 percent, enzyme agent liquid is added according to the amount of 10 percent, the rest is supplemented by distilled water, and the lactic acid fermentation liquor wastewater is completely transferred to a pretreatment unit for treatment,

the saccharification and fermentation unit then requires additional amounts of distilled water: 1.75/20% -1.75/40%) -1.75 x 10% ═ 4.27 tons per ton of lactic acid.

10. Distilled water requiring outward discharge: 4.4-4.27-0.13 ton/ton lactic acid.

Example 8

The lactic acid fermentation liquor sewage transfer treatment embodiment:

1. and controlling the amount of the lactic acid sewage. The total amount of the sewage of the lactic acid waste liquid is 1/6-1, namely 15.67 tons/ton of lactic acid according to the concentration of the lactic acid fermentation liquid of 6%.

2. And transferring the lactic acid wastewater to a receiving node for pretreatment unit treatment for optimization. The selectable sewage receiving nodes comprise four nodes of dispensing, dilute yellow humic acid black liquor, concentrated yellow humic acid black liquor and pulp washing, and different adding nodes can be selected according to different water qualities and water quantities.

In this embodiment, the lactic acid pulp washing sewage is preferentially used for the dispensing node, and the redundant sewage directly enters the four-section reverse washing unit.

3. Controlling the water consumption of the medicine preparation and the steaming. The set conditions are that the cellulose content is 35%, the raw material consumes 4 absolute dry tons/ton of lactic acid, the solid-liquid ratio is 1:3, the steam consumes 4 tons/ton of lactic acid, the water content of the raw material is 15%, the medicament dosage is 20%, the water content is 15%, the dewatering pulp squeezing concentration is 40%, the pulp washing dilution concentration is 10%, the cellulose content after pretreatment is 80%, 1.4 tons of pure cellulose/ton of lactic acid, 50% of yellow humic acid black liquor is obtained through evaporation and concentration, the yield of yellow humic acid is 3 tons/ton of lactic acid, and the lactic acid sewage transfer treatment capacity is 15.67 tons/ton of lactic acid.

Then the process of the first step is carried out,

(1) water consumption in cooking: cooking liquor ratio of 1:3, namely the solid content is 25 percent, and the water consumption is 4 tons/25 percent and 16 tons/ton of lactic acid

(2) The material carries the water yield: 4 ton with water for raw material 15% + 4 ton with water for medicine 20% + 15% + 4 ton with water for steam 5.77 ton/ton lactic acid

(3) Water supplement quantity: water consumption in cooking: 16-water content 5.77-10.23 ton/ton lactic acid

(4) Transferring and treating sewage quantity: 15.67 ton/ton lactic acid

(5) Transferring and treating the surplus sewage: 15.67-10.23-5.44 tons/ton lactic acid for the following four reverse washes.

4. And (5) cooking black liquor. And (3) defibering and squeezing pulp after cooking, wherein the concentration of the squeezed pulp is 40%, and the pulp is obtained, wherein 1.4/80% of the pulp is 1.75 ton/ton of lactic acid.

Then the process of the first step is carried out,

defibering and pulp squeezing to remove yellow humic acid black liquor: 4/25% -1.75/40% ═ 2.67 ton/ton lactic acid

5. The water consumption for washing the pulp. 1.75 tons of cellulose pulp, 10 percent of diluted pulp concentration and 40 percent of pulp squeezing concentration,

then the process of the first step is carried out,

water consumption for washing: 1.75/10% -1.75/40% ═ 13.13 tons/ton lactic acid, the source is two parts: firstly, the transfer treatment sewage is supplemented with 5.44 tons/ton lactic acid, and the rest 7.69 tons/ton lactic acid is supplemented with subsequent pulp washing water for deep hydrolysis of hemicellulose.

6. The hemicellulose hydrolysis pulp washing water is used for four-stage reverse washing. 7.69 tons of lactic acid hemicellulose pulp washing water per ton are used for four-stage reverse washing, and the rest 5.44 tons of hemicellulose hydrolysis pulp washing water per ton of lactic acid directly enters the yellow humic acid washing black liquor.

7. The amount of sewage to be evaporated: 2.67 percent of cooking black liquor, 13.13 percent of pulp washing and 5.44 percent of hemicellulose hydrolysis pulp washing water, 21.24 tons of lactic acid per ton

8. Amount of distilled water evaporated: calculated according to 2 tons of thick black liquor/ton of yellow humic acid dry powder,

obtaining the distilled water amount: 21.24-2 x 3-15.24 ton/ton lactic acid

9. Amount of water (distilled water) for decoloring bleaching and washing: 1.75/10% -1.75/40% ═ 13.13 tons/ton lactic acid

10. The amount of surplus distilled water: 15.24-13.13-2.11 ton/ton lactic acid

11. The saccharification and fermentation unit needs supplementary water. Preferably, the solid content of the saccharification substrate is 20%, the solid content of the cellulose pulp after pretreatment is 40%, the enzyme liquid is 10%, and the lactic acid fermentation liquor wastewater is completely transferred to a pretreatment unit for treatment, so that the water supplement amount required to be supplemented is as follows: (1.75/20% -1.75/40%) +1.75 x 10% ═ 4.28 tons/ton of lactic acid.

12. The entire production system requires a supplemental amount of fresh water. Preferably, the amount of fresh water to be replenished by the entire production system is: the lactic acid saccharification and fermentation unit has 4.28 tons and the pretreatment unit has 2.11 tons of residual distilled water per ton of lactic acid which is 2.17 tons, namely, 2.17 tons of clean water is consumed for producing 1 ton of lactic acid and 3 tons of fulvic acid dry powder.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and equivalents can be made in the technical solutions described in the foregoing embodiments, or equivalents thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Although the present invention has been described with reference to the specific embodiments, it should be understood by those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims

1. A factory production method of polymer grade cellulose lactic acid for co-producing fulvic acid is characterized by comprising the following steps:

producing lactic acid by using the purified cellulose component, and purifying to obtain polymer-grade lactic acid;

producing fulvic acid from the non-cellulosic component;

2. The industrial production method of the polymer grade cellulose lactic acid with the co-production of fulvic acid as claimed in claim 1, which is characterized by comprising the following steps:

(1) pretreating and separating to obtain purified cellulose and fulvic acid, removing impurities in lactic acid carried by raw materials, including lignin and phenolic substances hydrolyzed by the lignin, aldehydes and organic acids generated by hemicellulose hydrolysis, and protein, pectin and wax fat generated by non-cellulose components, and decolorizing;

(3) controlling and removing impurities formed by intermediate byproducts generated in the fermentation production process, including inorganic salt and acetic acid, and impurities formed by nutrient solution not consumed in the fermentation process, including pyruvic acid;

(4) decoloring;

(5) concentrating and dehydrating lactic acid, and transferring the generated sewage to a pretreatment unit for treatment;

(7) an integrated production system and a water circulation system, which comprises a technical scheme of water circulation of pretreatment, cycle treatment of fulvic acid black liquor and transfer treatment of lactic acid waste liquor and sewage,

finally, purified polymer-grade lactic acid and fulvic acid are obtained.

3. The industrial production method of polymer grade cellulose lactic acid with co-production of fulvic acid as claimed in claim 1, characterized in that high purity purified cellulose and fulvic acid are obtained by pretreatment separation, impurities brought into lactic acid by raw materials are removed, and the method is implemented in two steps:

firstly, pretreating and separating to obtain high-purity purified cellulose and fulvic acid;

the impurities brought into the lactic acid by the raw materials comprise lignin, phenolic substances hydrolyzed by the lignin, hemicellulose and organic heteroacid hydrolyzed by the hemicellulose, including acetic acid, furfural, hydroxymethyl furfural, formic acid, levulinic acid and protein, pigment, pectin and wax fat generated by hydrolysis of non-fibrous components;

the high-purity purified cellulose is characterized in that:

the content of the cellulose component is 70-95%, preferably 75-95%, and the content of the non-cellulose component is 30-5%, preferably 10-5%;

the non-cellulose components include cellulose components other than cellulose and non-fiber components in the fiber material;

the non-cellulose components except cellulose comprise lignin and hemicellulose, wherein the content of the hemicellulose is 2-10%, and the content of the lignin is 2-10%;

the organic heteropolyacid and other inhibitors are generated by hydrolyzing hemicellulose, and comprise methanol, furfural, 5-hydroxymethyl furfural, acetic acid and 2-hydroxybutyric acid, and the content of the organic heteropolyacid and the other inhibitors is 0-0.3%;

the pretreatment process comprises the following steps: performing ammonium sulfite cooking, sulfonating and hydrolyzing lignin, hydrolyzing hemicellulose, hydrolyzing pectin, wax and protein, and then performing defibering and washing to separate cellulose and all non-cellulose components except the cellulose;

and secondly, performing advanced treatment on the cellulose, including acidizing the cellulose pulp obtained in the first step to deeply hydrolyze hemicellulose, deeply delignify, decolor and deeply detoxify.

4. The industrial production method of polymer grade cellulose lactic acid with the co-production of fulvic acid according to claim 1, characterized in that cellulose and all non-cellulose components are separated by cooking, defibering and washing, specifically, a. the cooked cellulose pulp is obtained by cooking with an ammonium sulfite method, b. pulp squeezing and pulp refining defibering are carried out on the pulp, fulvic acid cooked thin black liquor is obtained by collection, c. pulp subjected to multi-section, preferably four-section reverse washing pulp washing is carried out on the pulp subjected to defibering by b, cellulose pulp and black liquor are separated, fulvic acid washed pulp thin black liquor and cellulose pulp are obtained by collection, d. the cooked thin black liquor and the washed pulp thin black liquor are collected and mixed to be sent to an evaporation station for evaporation and concentration, fulvic acid concentrated black liquor and distilled water are obtained; and (3) spraying and drying the thick yellow humic acid black liquor to obtain yellow humic acid dry powder, and washing cellulose pulp by using distilled water with the pH value of 7-9 after known salt control denitrification treatment.

5. The industrial production method of the polymer-grade cellulose lactic acid with the co-production of fulvic acid is characterized in that the cellulose is acidified to deeply hydrolyze the residual hemicellulose, and specifically, 1-3% of acid and 28-40% of slurry concentration are added firstly, mixed by a high-concentration mixer and then enter a reaction bin, the temperature is 80-95 ℃, and the temperature is kept for 60-120 min; then, washing pulp, and collecting washing pulp water for reverse washing and washing pulp in the four stages of the previous working procedure; so that 1-4%, preferably 2-3% of hemicellulose remains;

the pulp washing refers to pulp washing by using denitrified distilled water obtained by evaporating and concentrating the dilute fulvic acid black liquor or by using sewage generated in a subsequent decoloration bleaching process;

the acid is selected from one or more of inorganic acid, organic acid, amino acid and mineral acid, preferably phosphoric acid, sulfuric acid and hydrochloric acid.

6. The industrial production method of the polymer grade cellulose lactic acid with the co-production of fulvic acid as claimed in claim 1, characterized in that the cellulose is subjected to deep delignification, decolorization and deep detoxification treatment;

according to the requirements, the deep delignification is carried out by adopting a conventional method in pulping production, and oxygen delignification is preferably selected; the decolorization is carried out by adopting a conventional method in pulping production, hydrogen peroxide bleaching is preferred, and a pH regulator uses a sodium-free alkaline agent; the lignin content is 1-4%, preferably 2-3%, and the fiber pulp whiteness is 75-90% ISO;

the detoxification refers to the steps of washing and removing residual heteroacid such as acetic acid, 2-hydroxybutyric acid and the like in cellulose by using alkaline denitrified distilled water;

the sodium-free alkaline agent is preferably magnesium alkali, i.e. MgO, Mg (OH)₂、MgCO₃And Mg (HCO)₃)₂Ammonia, KOH, and NaOH.

7. The industrial production method of the polymer grade cellulose lactic acid with the co-production of fulvic acid according to claim 1, characterized by adopting ammonium sulfite cooking, specifically, using 10-25% of ammonium sulfite, adjusting pH 4-10 with acid and sodium-free alkali agent, liquid ratio 1: 2.5-4 ℃, the temperature is 140-175 ℃, preferably 140-160 ℃, the temperature is kept for 60-180 min, preferably 90-120 min;

the sodium-free alkali agent comprises magnesium alkali, i.e. MgO, Mg (OH)₂、MgCO₃And Mg (HCO)₃)₂At least one of the above components, ammonia water and KOH, with the amount of 1-7%, and the use of NaOH is limited.

8. The industrial production method of polymer grade cellulose lactic acid with fulvic acid co-production as claimed in claim 1, wherein the impurities formed by intermediate by-products generated by saccharification, fermentation and purification are removed and decolorized by a known method; firstly, adopting a sodium-free neutralizer, namely limiting the dosage of sodium ions in the saccharification and fermentation process, namely adopting a sodium-free alkaline neutralizer and adding additional sodium-free mineral nutrients; secondly, carrying out solid-liquid separation on lactic acid fermentation liquor obtained by simultaneous saccharification and saccharification fermentation, collecting undegraded residual lignin, adding the undegraded residual lignin into a pretreatment cooking part to produce fulvic acid, and thirdly, carrying out solid-liquid separation on calcium sulfate and magnesium sulfate precipitates generated by separating lactic acid and lactate to carry out harmless treatment; obtaining purified lactic acid liquid;

the sodium-free basic neutralizing agent comprises Ca (OH)₂CaO, MgOH, KOH, ammonia and urea;

the additional sodium-free nutrient may be selected from at least one of: for example mineral salts, for example mineral nitrogen, phosphates, sulphur and at least one of the trace elements such as zinc, magnesium, calcium, manganese, potassium, boron, iron, cobalt, copper, molybdenum, nickel, aluminium, in particular the mineral elements constituting the trace element fertilizer, preferably at least one of the trace elements potassium, zinc, magnesium, manganese, potassium, boron, iron, copper, molybdenum as a constituent of the fertilizer;

the collection of the undegraded residual lignin refers to that when saccharification and fermentation are carried out step by step, the saccharification liquid is subjected to solid-liquid separation after saccharification; when saccharification and fermentation are carried out synchronously, solid-liquid separation is carried out on the lactic acid fermentation liquor after the saccharification and fermentation are carried out simultaneously;

the known method for extracting lactic acid from the lactic acid fermentation broth includes, but is not limited to, at least one of a calcium salt method, an extraction method, an adsorption method, a membrane method, a molecular distillation method, and a reduced pressure distillation method.

9. The industrial production method of polymer grade cellulose lactic acid with fulvic acid co-production as claimed in claim 1, wherein the total amount of lactic acid wastewater is controlled and transferred, and the specific implementation scheme and algorithm are as follows:

(1) controlling the amount of the lactic acid sewage; preferably, the concentration of the lactic acid fermentation liquid is 10%, and the total amount of sewage of the lactic acid waste liquid is 9 tons/ton of lactic acid; preferably, the conversion rate of glucose-lactic acid is 80%, the conversion rate of cellulose-glucose is 90%, the concentration of saccharification substrate is 20%, and the cellulose content after pretreatment is more than 70%;

(2) transferring the lactic acid sewage to a receiving node for pretreatment unit treatment for optimization; the selectable sewage receiving nodes comprise four nodes of dispensing, dilute fulvic acid black liquor, concentrated fulvic acid black liquor and pulp washing, preferably, the dispensing node is selected at first, and redundant sewage directly enters the dilute fulvic acid black liquor or enters a four-section reverse washing unit according to the condition;

(3) controlling the water consumption of the medicine preparation and the cooking; the preferable set conditions are that the cellulose content of the raw material is 35 percent, the raw material consumes 4 absolute dry tons/ton of lactic acid, the solid-liquid ratio is 1:3, the steam consumes 4 tons/ton of lactic acid, the water content of the raw material is 15 percent, the medicament dosage is 20 percent, the water content is 15 percent, the concentration of dewatering and pulp squeezing is 40 percent, the concentration of pulp washing and dilution is 15 percent, the yield of purified cellulose is 1.4 tons/ton of lactic acid, the cellulose content after pretreatment and purification is 80 percent, the solid content of the yellow humic acid concentrated black liquor is 50 percent, the yield of the yellow humic acid is 3 tons/ton of lactic acid, and the transfer treatment capacity of lactic acid.

Then the process of the first step is carried out,

Secondly, carrying water quantity on the material: 4 ton with water for raw material 15% + 4 ton with water for medicine 20% + 4 ton with water for steam 15 ton 5.766 ton/ton lactic acid

Transferring the amount of the sewage to be treated: 9 ton/ton lactic acid

(4) The amount of black liquor water is cooked. And (3) defibering and squeezing pulp after cooking, wherein the concentration of the squeezed pulp is 40%, and the pulp is obtained, wherein 1.4/80% of the pulp is 1.75 ton/ton of lactic acid.

Then the process of the first step is carried out,

then the process of the first step is carried out,

water consumption for washing: 1.75/15% -1.75/40% ═ 7.34 ton/ton lactic acid

obtaining the yield of distilled water: 8.97-2 x 3-12.97 ton/ton lactic acid

(9) Distilled water is used for the water quantity of the saccharification and fermentation unit. Preferably, the solid content of the pretreated cellulose pulp is 40 percent, the solid content of the saccharification substrate is 20 percent, enzyme agent liquid is added according to the amount of 10 percent, the rest is supplemented by distilled water, and the lactic acid fermentation liquor wastewater is completely transferred to a pretreatment unit for treatment,

the saccharification and fermentation unit then requires additional amounts of distilled water: (1.75/20% -1.75/40%) -1.75 × 10% ═ 4.27 tons/ton of lactic acid.

10. The industrial production method of polymer grade cellulose lactic acid with fulvic acid co-production as claimed in claim 1, wherein a technical scheme and a method system of a system for separating all fiber raw materials into cellulose components and non-cellulose components, producing lactic acid from the cellulose components, and producing fulvic acid from all non-cellulose components such as separated lignin are provided; the method is also suitable for the industrial production of the cellulosic ethanol; the fiber raw materials comprise various wood fibers, non-wood plant fibers, various crop straws, wastes and residues and wastes of industrial processing, and specifically comprise: at least one of wheat and barley straws and wheat bran, corn straws and corncobs and industrial residues, rice and rice chaff, cotton straws and cotton boll hull cotton seed hulls, bean straws, rape stalks, peanut hulls, various tree twigs and offcuts, reeds, bamboos, bagasse, wattle and palm shells.