阅读说明：本技术 一种芦苇制备糠醛联产无胶纤维板的方法 (Method for preparing furfural and co-producing glue-free fiberboard from reed ) 是由 唐印 郭志刚 雷林 刘朝慧 李旭初 武长安 李刚 王明权 于 2019-08-01 设计创作，主要内容包括：本发明属于农作物秸秆资源综合利用领域,具体为一种芦苇汽爆提取木糖制备糠醛联产纤维板的方法。该方法包括以下步骤：1)压裂和切段；2)风选；3)稀醋酸预处理后压榨脱水后汽爆,汽爆后物料水洗；4)水提液去分馏塔；电渗析分离甲酸、乙酸和糠醛水溶液；5)还原糖混合物发酵后微滤；6)反渗透；7)得糠醛；8)得到含固体纤维素、木质素及少量半纤维素的混合物处理后烘干；9)制无胶纤维板。该方法采用高压水蒸汽汽爆,使芦苇中的半纤维素更容易在相对低温的蒸汽爆破条件下水解为单糖或者低聚糖,减低蒸汽爆破的温度还能减轻木糖等戊糖的进一步降解,提高芦苇的利用率。(The invention belongs to the field of comprehensive utilization of crop straw resources, and particularly relates to a method for preparing furfural co-production fiberboard by extracting xylose from reed through steam explosion. The method comprises the following steps: 1) fracturing and cutting; 2) winnowing; 3) carrying out steam explosion after squeezing and dewatering after pretreatment of dilute acetic acid, and washing materials after steam explosion; 4) the water extract goes to a fractionating tower; electrodialysis separation of formic acid, acetic acid and furfural aqueous solution; 5) carrying out microfiltration on the reducing sugar mixture after fermentation; 6) reverse osmosis; 7) obtaining furfural; 8) treating the mixture containing solid cellulose, lignin and a small amount of hemicellulose, and drying; 9) and (5) preparing the glue-free fiber board. The method adopts high-pressure steam explosion, so that hemicellulose in the reed can be hydrolyzed into monosaccharide or oligosaccharide more easily under relatively low-temperature steam explosion conditions, the steam explosion temperature is reduced, the further degradation of pentose such as xylose and the like can be reduced, and the utilization rate of the reed is improved.)

1. a method for preparing furfural and coproducing a glue-free fiberboard by using reeds is characterized by comprising the following steps:

1) the raw material reed is crushed and cut into sections, and the length is 20-40 mm;

2) Separating reed leaves, reed flowers and flute membrane impurities in the reeds by wind power conveying, wherein the rest reeds are steam explosion raw materials;

3) Adding 1% diluted acetic acid into the reed steam explosion raw material obtained in the step 2), uniformly mixing by using a mixer, maintaining for 30 minutes, and then sending the reed after acid mixing into a steam blaster for instantaneous blasting; grinding the steam-exploded material into fluffy fibers by a high-concentration mill, adding water, washing, and squeezing for dewatering to obtain a mixture containing solid cellulose, lignin and a small amount of hemicellulose and a water extract;

4) Feeding the water extract obtained in the step 3) into a fractionating tower, collecting aqueous solution containing formic acid, acetic acid and furfural at the tower top, and separating the aqueous solution containing formic acid, acetic acid and furfural by electrodialysis; obtaining a reducing sugar mixture at the bottom of the tower;

5) Adding yeast into the reducing sugar mixture obtained in the step 4) to ferment glucose into ethanol and remove the ethanol; removing thallus from the fermentation liquor by using a microfiltration membrane to obtain mixed liquor containing xylose and arabinose;

6) microfiltering the permeated mixed solution containing xylose and arabinose, and concentrating the mixed solution to 30 Wt% by using a reverse osmosis membrane, wherein the operating pressure of the reverse osmosis membrane is 4-6 MPa;

7) Taking 30 Wt% of xylose mixed liquor, a catalyst and a polymerization inhibitor according to the weight ratio of 1: 0.04-0.08: continuously feeding the mixture into a liquid-liquid mixer at a ratio of 0.001 for mixing, pumping the mixture into a preheater, heating the mixture to the temperature of 160-; the method comprises the following steps of enabling reactants to stay in a tubular reactor for 8-15 minutes and enter a reaction extraction tower, keeping the temperature of the tower at 160-200 ℃ for continuous reaction, enabling furfural generated in the reaction mixture to be redissolved in a solvent after the reaction mixture is contacted with the solvent flowing down from the upper part, enabling the furfural to flow to a settling section at the lower part of the tower, cooling the furfural to 40 ℃ through a cooler, enabling the furfural to enter a disc centrifugal separator, separating a small amount of water from a solvent phase, enabling the solvent phase to enter a fractionating tower, and rectifying crude furfural obtained at the top of the tower to obtain a finished product furfural; the solvent obtained at the tower bottom is returned to be used as ingredients; and (3) moving the water phase in the reaction liquid entering the reactive extraction tower to the upper part of the tower for continuous reaction, extracting by the solvent added at the tower top, continuously moving the water phase upwards, discharging from an outlet at the tower top, performing heat exchange, then entering a centrifugal extractor, further extracting and separating by the newly added solvent, returning the solvent phase to the tower top, and mixing the water phase with the water phase separated by a centrifuge at the tower bottom for treatment.

8) soaking the mixture containing solid cellulose, lignin and a small amount of hemicellulose obtained in the step 3) in 1.2 wt% of NaOH aqueous solution for 20-40 min, wherein the solid-to-liquid ratio is 1: 4, the temperature is 100 ℃ and 120 ℃, then the mixture is squeezed and dried until the water content is 10-15 percent;

9) and (3) uniformly paving the dried material obtained in the step (8) on a hot press plate, and maintaining the pressure at 2-3 MPa, the hot pressing temperature at 160-.

2. The method for preparing furfural and coproducing the glue-free fiber board by using reed as claimed in claim 1, wherein the method comprises the following steps: the solid-liquid ratio in the mixer in the step 3) is 1: 4-10; the mixer is a ribbon mixer or a drum mixer.

3. The method for preparing furfural and coproducing the glue-free fiber board by using reed as claimed in claim 1, wherein the method comprises the following steps: the conditions of the instant blasting in the steam blaster are as follows: the steam pressure is 1.2-2.0 Mpa, the temperature is 180-; preparing the materials after steam explosion into thick pulp with the concentration of 20-30%, grinding the thick pulp by a high-concentration mill, and washing the thick pulp by hot water with the mass of 10 times in a continuous pulp washer, wherein the temperature of the hot water is 70 ℃.

4. the method for preparing furfural and coproducing the glue-free fiber board by using reed as claimed in claim 1, wherein the method comprises the following steps: adding water into the reducing sugar mixture obtained in the step 4) to adjust the concentration to 12-24 Wt%, adding urea and phosphoric acid to adjust the pH value to 4.4-5.2, adding saccharomyces cerevisiae, maintaining the fermentation temperature at 30-60 ℃, fermenting for 48-72 h, and filtering the yeast from the obtained fermentation liquor by using a microfiltration membrane with the diameter of 0.1 mu m; then removing protein macromolecular impurities by using an ultrafiltration membrane of 1000 Da.

5. The method for preparing furfural and coproducing the glue-free fiber board by using reed as claimed in claim 1, wherein the method comprises the following steps: the catalyst is organic acid; the dosage is 3-8 wt%; the used solvents are p-nitrotoluene and diisopropyl biphenyl, and the weight ratio of the materials to the solvents is 1: 2-3; the polymerization inhibitor is triphenyl phosphine, thiourea or hydroquinone.

6. The utility model provides a reaction extraction device of xylose liquid preparation furfural, the device includes reaction extraction tower (12), centrifugal extractor (13), solvent phase centrifuge (16), fractionating tower (17) and furfural rectifying column (18), its characterized in that: a xylose liquid conveying pipeline with a xylose liquid metering pump (2) and an acetic acid conveying pipeline with an acetic acid metering pump (4) are connected and then connected with a mixing pump (6), and the mixing pump (6) is connected with the lower part of a reaction extraction tower (12); the bottom of the reaction extraction tower (12) is connected with a solvent phase centrifugal separator (16) and then connected with the middle part of a fractionating tower (17), and the top of the fractionating tower (17) is connected with the middle part of a furfural rectifying tower (18); the bottom of the fractionating tower (17) is divided into two branch pipes after passing through a solvent tank (9) and a solvent metering pump (10) in sequence, one branch pipe is connected with a centrifugal extractor (13) and a solvent feeding pump (14) and then connected with the upper part of the reaction extraction tower (12), and the other branch pipe is connected with a discharge hole at the top of the reaction extraction tower (12) through a pipeline which is sequentially provided with a water phase heat exchanger (11) and a pressure reducing valve (22).

7. The reactive extraction plant for preparing furfural from xylose liquor according to claim 6, characterized in that: the xylose liquid metering pump (2) is connected with the xylose storage tank (1); the acetic acid metering pump (4) is connected with the acetic acid storage tank (3); a polymerization inhibitor adding device is arranged on a pipeline at a feed inlet of the mixing pump (6), the polymerization inhibitor adding device comprises a polymerization inhibitor meter (5) and a polymerization inhibitor storage tank, and the polymerization inhibitor meter (5) is connected with the polymerization inhibitor storage tank; a heat exchanger (7) and a preheater (8) are sequentially arranged on a pipeline between the mixing pump (6) and the reactive extraction tower (12); a pressure reducing valve and a solvent phase heat exchanger (15) are sequentially arranged between the reaction extraction tower (12) and the solvent phase centrifugal separator (16); the top of the furfural rectifying tower (18) is connected with a furfural condenser (19) and then connected with a furfural storage tank (20); the water phase heat exchanger (11) is respectively connected with a solvent feeding pump (14) of the centrifugal extractor (13).

8. The reactive extraction plant for preparing furfural from xylose liquor according to claim 6, characterized in that: the reaction extraction tower (12) is a turbine stirring type reaction extraction tower, the turbine reaction extraction tower is divided into four sections, the uppermost section is a water phase and solvent phase separation clarification section (12-5), the middle section is a reaction extraction section (12-4), the lower part of the reaction extraction section is a feeding section (12-3), and the lowermost end of the reaction extraction section is a solvent phase clarification section (12-1); a reaction liquid feeding pipe (12-2) is arranged at the upper end of the solvent phase clarification section (12-1), the reaction liquid feeding pipe (12-2) is circularly distributed in the tower, two rows of circular small holes with 60 degrees are formed on the pipe, and a sieve plate (12-13) is arranged above the reaction liquid feeding pipe (12-2); a solvent feeding pipe (12-8) is arranged at the lower part of the water phase and solvent phase separation clarification section (12-5); and heating jackets (12-12) are welded outside the tower barrels of the feeding section (12-3) and the reactive extraction section (12-4) of the reactive extraction tower (12), and the heating jackets (12-12) are connected with a heat-preservation hot oil furnace of the reactive extraction tower.

9. the reactive extraction plant for preparing furfural from xylose liquor according to claim 6, characterized in that: the reaction extraction tower (12) is provided with a stirrer (12-6), a stirring shaft (12-9) connected with the stirrer (12-6) extends into a feeding section (12-3) in the reaction extraction tower (12), and the stirring shaft (12-9) is provided with a stirring paddle (12-11).

10. The reactive extraction plant for preparing furfural from xylose liquor according to claim 6, characterized in that: a baffle (12-10) is arranged at the reactive extraction section (12-4) of the reactive extraction tower (12); a water phase discharge hole (12-7) is arranged at one side of the water phase and solvent phase separation clarification section (12-5); a solvent feeding pipe (12-8) is arranged on one side of the upper part of the reactive extraction section (12-4), and a discharging hole (12-14) is arranged at the bottom of the reactive extraction tower (12).

Technical Field

The invention belongs to the field of comprehensive utilization of crop straw resources, relates to a process technology for co-producing furfural from crop straws, particularly emphasizes a method for directly preparing furfural from steam-exploded washing substances of the crop straws and preparing a glue-free fiberboard from residual solids, and particularly relates to a method for preparing furfural and co-producing the glue-free fiberboard from reeds.

Background

with the increasing shortage of wood supply, finding wood substitute raw materials is receiving more and more extensive attention. Researches prove that the reed can replace wood for producing artificial boards. The reed resource is sufficient in China, the distribution area is very wide, and the main reed producing areas are as many as fourteen. The reed is used as paper making raw material, other industrial purposes are not available, and the felled reed is abandoned or burnt, which brings certain pressure to the environment of the producing area. The artificial board of reed has great significance in developing artificial boards of reed, can relieve the contradiction between supply and demand of wood, protect forest resources and ecological environment, and drive the economic development of reed producing areas.

The reed belongs to perennial plants, and grows better in the next year after felling, so that the yield is high, and the requirement of a factory on a large scale can be met. The separated stalk reed has high fiber yield and good shape, and can be produced into reed fiber boards with various thicknesses and densities by a flat plate hot pressing method or a compression roller hot pressing method according to different use requirements. The performance of reed fiber board produced by urea-formaldehyde resin and other adhesives can be compared favorably with the performance of medium-density fiber board produced by wood. The product is mainly used in the fields of packaging, floors, furniture, buildings, decoration and the like, so that the application prospect of producing fiberboards with different densities by using the reeds is wide.

The ash content in the reed is high, the main component in the ash content is silicon dioxide, and the silicon dioxide and fatty substances form a wax layer with hard surface skin, the wax layer is non-polar substances, the wettability is poor, the surface free energy is low, so that a water-soluble adhesive is difficult to permeate, the bonding strength of the board is low, and the development of the reed fiber board is restricted. In order to solve this problem, it is necessary to perform surface treatment on the reed to destroy the cell wall structure and improve the adhesive force. The treatment mainly includes physical, chemical and biological methods. The physical method mainly comprises a mechanical hot grinding method and a steam explosion method, and the patent CN101172351 proposes a method for preparing an artificial board without glue by using bamboo hot grinding, but the application range is limited because the hot grinding temperature is higher, the hot pressing time is longer, the energy consumption is higher, and the production rate is lower. The chemical method is mainly characterized in that a plurality of chemical reagents are added to activate natural macromolecules in the straw raw material to generate active groups, and the chemical method mainly comprises an oxidation bonding method, a free radical initiation method, an acid catalysis condensation method and an alkali solution activation method. The biological method mainly utilizes microbes or enzyme to catalyze the degradation of straw raw material components to generate active groups. At present, the straw adhesive-free technology is not a single method but a combination of multiple methods, for example, patent CN101214678 uses a hot grinding and oxidant applying combined activation method to prepare a bamboo fiber artificial board, and patent CN1412092 proposes a method for preparing a straw modified material by utilizing steam explosion to treat straws and then inoculating phanerochaete chrysosporium to solid state fermentation activated straw materials for hot pressing. Although no external adhesive is added in the method, the production efficiency of the pressing plate is low due to the long growth period of microorganisms, and meanwhile, the product is easy to be unstable due to the uneven enzyme activity distribution of laccase. At the same time, the methods cannot utilize the reed raw material more valuably. Another problem is that the hemicellulose is not fully utilized during the treatment.

Disclosure of Invention

the invention provides a method for preparing furfural and coproducing a glue-free fiberboard by using reeds based on the technical problems. The method adopts high-pressure steam explosion, so that hemicellulose in the reed can be hydrolyzed into monosaccharide or oligosaccharide more easily under relatively low-temperature steam explosion conditions, the steam explosion temperature is reduced, the further degradation of pentose such as xylose and the like can be reduced, and the utilization rate of the reed is improved.

in order to achieve the above purpose, the technical scheme of the invention is as follows:

The chemical composition of the reed is compared with other plant fibers: unit: is based on

A method for preparing furfural and coproducing a glue-free fiberboard by using reeds comprises the following steps:

1) The raw material reed is crushed and cut into sections, and the length is 20-40 mm;

2) separating reed leaves, reed flowers and flute membrane impurities in the reeds by wind power conveying, wherein the rest reeds are steam explosion raw materials;

3) adding 1% (wt/wt) diluted acetic acid into the reed steam explosion raw material obtained in the step 2), uniformly mixing by using a mixer, and maintaining for 30 minutes, wherein the solid-to-liquid ratio in the mixer is 1: 4-10, the mixer is a ribbon mixer or a drum mixer. Then, the reed after acid mixing is pressed and dehydrated, the water content of the reed after treatment is 40-50%, and the reed is sent into a steam blaster for instant blasting; grinding the steam exploded material into fluffy fiber by a high-concentration mill, adding water, washing, and squeezing for dewatering to obtain a mixture containing solid cellulose, lignin and a small amount of hemicellulose and a water extract.

Preferably, the conditions for instantaneous blasting in the steam blaster are: the steam pressure is 1.2-2.0 Mpa, the temperature is 180-.

Preferably, the material after steam explosion is prepared into 20-30% thick pulp, the thick pulp is ground by a high-consistency mill and washed by hot water with the mass of 10 times of that of a continuous pulp washer, and the temperature of the hot water is 70 ℃.

4) Feeding the water extract obtained in the step 3) into a fractionating tower, collecting aqueous solution containing formic acid, acetic acid and furfural at the tower top, and separating the aqueous solution containing formic acid, acetic acid and furfural by electrodialysis; obtaining a reducing sugar mixture at the bottom of the tower;

5) Adding yeast into the reducing sugar mixture obtained in the step 4) to ferment glucose into ethanol and remove the ethanol; and (4) removing thalli from the fermentation liquor by using a microfiltration membrane to obtain a mixed liquor containing xylose and arabinose.

Preferably, the reducing sugar mixture obtained in the step 4) is firstly added with water to be prepared into 12-24 Wt%, then urea and phosphoric acid are added to adjust the pH value to 4.4-5.2, and then saccharomyces cerevisiae is added to maintain the fermentation temperature at 30-60 ℃ and ferment for 48-72 h, so that glucose in the reducing sugar mixture is fermented into ethanol and removed. Filtering the fermentation liquor with 0.1 μm microfiltration membrane to remove yeast; then removing protein macromolecular impurities by using a 1000Da ultrafiltration membrane to obtain a mixed solution containing xylose and arabinose.

6) Microfiltering the permeated mixed solution containing xylose and arabinose, and concentrating the mixed solution to 30 Wt% by using a reverse osmosis membrane, wherein the operating pressure of the reverse osmosis membrane is 4-6 MPa;

7) Treating by using a reaction extraction device for preparing furfural from xylose liquid: taking 30 Wt% of xylose mixed liquor, a catalyst and a polymerization inhibitor according to the weight ratio of 1: 0.04-0.08: continuously feeding the mixture into a liquid-liquid mixer at a ratio of 0.001 for mixing, pumping the mixture into a preheater, heating the mixture to the temperature of 160-; the reaction product stays in the tubular reactor for 8-15 minutes and enters a reaction extraction tower for continuous reaction, a reaction mixture flows to a lower settling section of the tower after contacting with a solvent flowing down from the upper part, the reaction mixture is cooled to 40 ℃ by a cooler and enters a disc centrifugal separator, a small amount of water in a solvent phase is separated out, the solvent phase enters a fractionating tower, and crude furfural obtained from the top of the tower is rectified to obtain a finished product furfural; the solvent obtained at the tower bottom is returned to be used as ingredients; and (3) moving the water phase in the reaction liquid entering the reaction extraction tower to the upper part of the tower to be extracted by the solvent added at the tower top, continuously moving the water phase upwards, continuously carrying out the reaction, discharging the reaction liquid from an outlet at the tower top, carrying out heat exchange by a heat exchanger, entering a centrifugal extractor, further extracting and separating by the newly added solvent, returning the solvent phase to the tower top, and mixing the water phase with the water phase separated by a centrifuge at the tower bottom for treatment.

Preferably, the catalyst is organic acid acetic acid; the dosage is 3-8 wt%; the used solvents are p-nitrotoluene and diisopropyl biphenyl, and the weight ratio of the materials to the solvents is 1: 2-3. the polymerization inhibitor is triphenyl phosphine, thiourea or hydroquinone.

8) Soaking the mixture containing solid cellulose, lignin and a small amount of hemicellulose obtained in the step 3) in 1.2 wt% of NaOH aqueous solution for 20-40 min, wherein the solid-to-liquid ratio is 1: 4, the temperature is 100 ℃ and 120 ℃, and then the mixture is squeezed and dried until the water content is 10-15%.

9) And (3) uniformly paving the dried material obtained in the step (8) on a hot press plate, and maintaining the pressure at 2-3 MPa, the hot pressing temperature at 160-.

preferably, the tubular reactor is internally provided with reaction tubes with different structural elements, the tubes are internally provided with static mixer elements of any one of SV, SK and SH types to promote the reactants to be uniformly mixed and carry out primary reaction, the length of the tubular reactor is 6-10 m, and the reaction tubes are connected with one another by 180-degree elbows to form a unit mixed reactor.

The reaction extraction device for preparing furfural from xylose liquid comprises a reaction extraction tower, a centrifugal extractor, a solvent phase centrifugal separator, a fractionating tower and a furfural rectifying tower; wherein the xylose liquid metering pump is connected with the xylose storage tank; the acetic acid metering pump is connected with the acetic acid storage tank; a xylose liquid conveying pipeline with a xylose liquid metering pump and an acetic acid conveying pipeline with an acetic acid metering pump are connected and then connected with a mixing pump, and the mixing pump is connected with the lower part of the reaction extraction tower; the bottom of the reaction extraction tower is connected with the solvent phase centrifugal separator and then connected with the middle part of the fractionating tower, and the tower top of the fractionating tower is connected with the middle part of the furfural rectifying tower; the bottom of the fractionating tower is divided into two pipelines after passing through a solvent tank and a solvent metering pump in turn, one branch is connected with the centrifugal extractor and a solvent feed pump and then connected with the upper part of the reactive extraction tower, and the other branch is connected with a discharge hole at the top of the reactive extraction tower through a pipeline which is sequentially provided with a water phase heat exchanger and a pressure reducing valve; the water phase heat exchanger is respectively connected with a solvent feed pump of the centrifugal extractor, the water phase heat exchanger exchanges heat with the solvent entering the reaction extraction tower, the water phase heat exchanger enters the centrifugal extractor for further extraction after exchanging heat with the solvent entering the reaction extraction tower, the solvent phase and the fresh solvent are pumped into the reaction extraction tower through the solvent feed pump, and the water phase is additionally treated.

A polymerization inhibitor adding device is arranged on a pipeline at a feed inlet of the mixing pump, and comprises a polymerization inhibitor meter and a polymerization inhibitor storage tank, wherein the polymerization inhibitor meter is connected with the polymerization inhibitor storage tank to ensure quantitative addition of the polymerization inhibitor; a heat exchanger and a preheater are sequentially arranged on a pipeline between the mixing pump and the reactive extraction tower.

A pressure reducing valve and a solvent phase heat exchanger are sequentially arranged between the reaction extraction tower and the solvent phase centrifugal separator.

The top of the furfural rectifying tower is connected with a furfural condenser and then connected with a furfural storage tank, so that furfural gas coming out of the top of the furfural rectifying tower enters the furfural condenser.

The reaction extraction tower is a turbine stirring type reaction extraction tower, the turbine reaction extraction tower is divided into four sections, the uppermost section is a water phase and solvent phase separation clarification section, the middle section is a reaction extraction section, a feeding section is arranged below the reaction extraction section, and the lowermost end is a solvent phase clarification section.

the upper end of the solvent phase clarification section is provided with a reaction liquid feeding pipe, the reaction liquid feeding pipes are circularly distributed in the tower, two rows of circular small holes with the angle of 60 degrees are formed in the pipes, and a sieve plate is arranged above the reaction liquid feeding pipes; and a solvent feeding pipe is arranged at the lower part of the clarification section for separating the water phase from the solvent phase.

and heating jackets are welded outside the feeding section of the reactive extraction tower and the tower barrels of the reactive extraction tower, and the heating jackets are connected with the heat-preservation hot oil furnace of the reactive extraction tower.

The reaction extraction tower is provided with a stirrer, a stirring shaft connected with the stirrer extends into a feeding section in the reaction extraction tower, and the stirring shaft is provided with a stirring paddle.

A baffle is arranged at the reaction extraction section in the reaction extraction tower; a water phase discharge port is arranged on one side of the water phase and solvent phase separation clarification section; a solvent feeding pipe is arranged on one side of the upper part of the reactive extraction section, and a discharge hole is arranged at the bottom of the reactive extraction tower.

The invention is also suitable for the process for preparing furfural by processing corn stalks, cotton stalks, wheat straws, rice straws, bamboo, bagasse/xylose mother liquor and other materials.

In the application, high-pressure steam explosion is adopted, water can be used as an acid catalyst at a high temperature to promote hemicellulose to be hydrolyzed into xylose, but H ⁺ provided by water at a certain temperature is limited, so that a higher steam explosion temperature is required, xylose can be further decomposed into furfural at a high temperature, low-concentration acetic acid is used for pre-soaking the reed before steam explosion pretreatment, a certain amount of H ⁺ can be provided as the catalyst, the hemicellulose in the reed can be more easily hydrolyzed into monosaccharide or oligosaccharide under the relatively low-temperature steam explosion condition, the steam explosion temperature is reduced, further degradation of pentose such as xylose can be reduced, and the utilization rate of the reed is improved.

Compared with the prior art, the invention has the beneficial effects that:

The method comprises the steps of (I) treating reed by a steam explosion technology, instantly spraying and damaging a cell wall structure at high temperature, improving the active group content of three components, directly degrading hemicellulose into xylose, extracting the xylose by using water, producing furfural by a continuous reaction extraction tower after treatment and concentration, and combining a polymerization inhibitor, so that the occurrence of side reaction in the traditional production of furfural is reduced, the yield of furfural is improved, the yield of waste residue is reduced, and the environmental pollution is reduced.

and (II) the pentosan content of the reed reaches 25.23 percent, the pentosan is converted into xylose, and the xylose is dehydrated and cyclized to produce furfural, so that the value of the product is increased. The generated xylose solution is separated to carry out dehydration reaction independently, so that the steam consumption in the reaction process can be reduced, and the problem that the furfural refining is not facilitated due to the formation of impurities in the final furfural aqueous solution caused by the decomposition of cellulose and lignin in a one-step method is solved.

And thirdly, acetic acid is used as a catalyst in the reaction extraction process, so that the corrosion of equipment is reduced, and the selection of materials for the equipment is facilitated.

the main problems of reed as the raw material of artificial board are its high ash content and the existence of silicon covering the surface of fiber, which makes reed show hydrophobic property. The bonding strength of the reed and the urea-formaldehyde resin adhesive is not high, the surface wettability of reed fibers can be obviously improved through steam explosion treatment and alkali treatment, and the problem of low strength of artificial boards made of reeds can be well solved.

And (V) treating the solid material by alkali, and performing condensation reaction on cellulose, residual hemicellulose and lignin in the raw material under a high-temperature pressing condition to form an adhesive effect, so that the adhesive-free gluing of the reed fiber is realized, the addition cost of the adhesive is saved, the process and the production line are simplified, the environmental pollution caused by the synthetic resin adhesive is reduced, and the production cost is reduced.

And sixthly, the reaction extraction device for preparing furfural from xylose liquid adopted in the invention has reasonable design structure and high working efficiency, and can better realize continuous operation.

description of the drawings:

FIG. 1 is a schematic view of the process flow of the method for preparing furfural coproduction glue-free fiberboard from reed.

FIG. 2 is a schematic diagram showing the connection relationship of the structures in the reaction extraction apparatus for preparing furfural from xylose liquor according to the present invention.

wherein, 1 is a xylose liquid storage tank, 2 is a xylose liquid metering pump, 3 is an acetic acid storage tank, 4 is an acetic acid metering pump, 5 is a polymerization inhibitor meter, 6 is a mixing pump, 7 is a heat exchanger, 8 is a preheater, 9 is a solvent storage tank, 10 is a solvent metering pump, 11 is a water phase heat exchanger, 12 is a reaction extraction tower (turbine extraction tower), 13 is a centrifugal extractor, 14 is a solvent feeding pump, 15 is a solvent phase heat exchanger, 16 is a solvent phase centrifugal separator, 17 is a fractionating tower, 18 is a furfural rectifying tower, 19 is a furfural condenser, 20 is a furfural storage tank, and 22 is a pressure reducing valve.

FIG. 3 is a schematic diagram of a reactive extraction column according to the present invention.

Wherein 12-1 is a solvent phase clarification section, 12-2 is a reaction liquid feeding pipe, 12-3 is a feeding section, 12-4 is a reaction extraction section, 12-5 is a water phase clarification section, 12-6 is a stirrer, 12-7 is a water phase discharging port, 12-8 is a solvent feeding pipe, 12-9 is a stirring shaft, 12-10 is a tower plate, 12-11 is a stirring paddle, 12-12 is a heating jacket, 12-13 is a sieve plate, and 12-14 is a discharging port.

FIG. 4 is a schematic view showing the positional relationship between the feed pipe for the reaction solution and the sieve plate in the present invention.

FIG. 5 is a schematic view showing the distribution of small holes in the reaction liquid feed pipe according to the present invention.

FIG. 6 is a schematic view showing the distribution of small holes in the solvent feed pipe according to the present invention.

Detailed Description

in order to facilitate the understanding of the present invention, the process described in the present invention will be further described with reference to the accompanying drawings and the detailed description. It should not be understood that the scope of the above-described subject matter of the present invention is limited to the following examples.

the percentages used in the present invention are, unless otherwise specified, all expressed in terms of mass percentage, i.e., wt%. (ii) a The solid-to-liquid ratio as used in this application refers to the ratio of the mass of the solid g to the volume of the liquid mL.

A reaction extraction device for preparing furfural from xylose liquid comprises a reaction extraction tower 12, a centrifugal extractor 13, a solvent phase centrifugal separator 16, a fractionating tower 17 and a furfural rectifying tower 18. Wherein the outlet at the bottom of the xylose liquid storage tank 1 is connected to the inlet of the xylose liquid metering pump 2, and the outlet of the xylose liquid metering pump 2 is connected to the inlet of the mixing pump 6; an outlet at the lower part of the acetic acid storage tank 3 is connected to an inlet of an acetic acid metering pump 4, an outlet of the acetic acid metering pump 4 and an outlet of a resistance agent meter 5 are simultaneously connected to an inlet of a mixing pump 6, the mixed materials enter a heat exchanger 7 and are preheated by a preheater 8, the preheated materials enter the lower part of a reaction extraction tower 12 and are contacted with a solvent flowing down from the upper part of the tower, furfural generated by reaction enters a solvent phase, the furfural flows downwards to the lower section of the reaction extraction tower for sedimentation and separation, the solvent phase is cooled and decompressed by a solvent heat exchanger 15, is discharged from the bottom of the tower and enters a solvent phase centrifugal separator 16, and the solvent phase separated by the solvent phase centrifugal separator enters a fractionating; the solvent from the bottom of the fractionating tower 17 enters a solvent storage tank 9 for standby; the solvent is divided after being measured by a solvent metering pump 10, one part of the solvent enters a water phase heat exchanger 11, the other part of the solvent enters a centrifugal extractor 13, the solvent phase from the centrifugal extractor 13 is pumped into a reaction extraction tower 12 through a solvent feeding pump-14, furfural steam from the top of a fractionating tower 17 enters a rectifying tower 18, the furfural steam from the top of the tower enters a storage tank 20 after being condensed, and the water phase discharged from the top of the reaction extraction tower enters the centrifugal extractor after being cooled by the heat exchanger 11.

the reaction extraction tower is of a turbine stirring type, the turbine reaction extraction tower is divided into four sections, the uppermost section is a water phase clarification section 12-5, a solvent enters from a solvent feeding pipe 12-8 at the lower part of the water phase clarification section 12-5, the middle part is a reaction extraction section 12-4, and the reaction extraction tower consists of a series of turbine stirring paddles 12-11 and annular tower plates 12-10 separated from the turbine stirring paddles 12-11; the two phases continuously pass through the reactive extraction section 12-4 in a countercurrent mode depending on the density difference, the solvent is a continuous phase, and the water phase is a dispersed phase. Here, the reaction for producing furfural by dehydration of xylose is continuously carried out, and the produced furfural enters the solvent phase. The turbine paddles 12-11 provide the necessary radial mixing and phase dispersion and prevent stratification of the reaction solution with the solvent; annular trays 12-10 reduce axial back-mixing of the fluid while achieving optimum dispersed phase retention while retaining droplets of the dispersed phase. Below the reactive extraction section 12-4 is a feed section 12-3, and at the lowermost end is a solvent phase clarification section 12-1, where the solvent phase is separated from the aqueous phase.

The feed inlet of the reaction liquid feed pipe 12-2 of the reaction extraction tower is a circular water phase distribution pipe in the tower, two rows of circular small holes with 60 degrees are arranged on the pipe, and a sieve plate 12-13 is arranged above the distribution pipe, so that the back mixing of materials can be prevented. The feed inlet of the solvent feed pipe 12-8 is positioned at the lower part of the water phase clarification section 12-5; the inlet of the reaction liquid feed pipe 12-2 is located at the upper part of the solvent phase clarification section. Heating jackets 12-12 are welded outside the tower barrels of the feeding section 12-3 and the reactive extraction section 12-4, and heat carriers are supplied for heat preservation by a heat preservation oil furnace of the reactive extraction tower.

The water phase from the top of the reactive extraction tower 12 and the solvent returned to the tower exchange heat in a water phase heat exchanger-11; the solvent phase coming out from the lower part of the clarifying section of the reactive extraction tower 12 and the reaction liquid entering the tower exchange heat in a solvent phase heat exchanger-15.

the temperature and flow of the reaction liquid and the solvent, and the temperature and pressure in the reactive extraction tower are controlled by PID regulation.