A process for the efficient mass transfer disassembly of polymeric biomass using a tidal method

Abstract

The present application relates to a process for synthesizing bio-based sulfonate by efficiently mass transfer disassembling poly-biomass through a similar tidal method, that is, large-size solid materials are used to remove gas in the pore network of raw materials as much as possible through vacuum, to promote the rapid penetration of reaction liquid, to separate the solid materials from the solution, to reduce the soaking liquid phase resistance when the reaction completed material is removed from the pore, to facilitate the smooth discharge of the reaction completed liquid and the dissolved product from the solid material and the smooth entry of the new reaction liquid material, this method is similar to "tide", which can effectively reduce the gas-liquid mass transfer resistance and improve the reaction efficiency. By using this biomass particle vacuum first, then soaking SO3 / 1,2-dichloroethane, separating the solution and reacting for a period of time, then vacuumizing again, then soaking SO3 / 1,2-dichloroethane, after 2-3 similar "tide" reactions, the sulfonation conversion rate of 30 mesh coarse particle biomass raw material can reach more than 90%, while the conversion rate of the original process of 150 mesh raw material is only about 65%.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of " tidal method " is carried out by biomass modification processing efficient mass transfer technology, belongs to the field of biomass processing production. BACKGROUND

[0002] The annual biomass synthesis amount on earth is as high as 170 billion tons, but only 2% is utilized. The characteristics of difficult solubility, difficult melting and difficult processing of biomass limit its application. Plants are the largest growth and most widely distributed biomass. Plant cell walls are mainly composed of three macromolecular materials: cellulose (30%-50%), hemicellulose (15%-35%), and lignin (10%-30%). The fiber bundles in the crystalline region are difficult to disassemble and aggregate, while hemicellulose and lignin are mainly distributed in the non-crystalline region, with larger intermolecular distance and relatively easy to disassemble. The large number of hydrogen bonds in the structure of biological macromolecules is the main reason for the poor water solubility of biomass. In plant tissues, the crystalline region and the amorphous region are arranged alternately, showing a structure similar to "reinforced concrete". As can be seen from the drawings, plant cell walls are actually composed of crystalline fiber bundles formed by cellulose molecules and hemicellulose and lignin wrapped and filled between them. Micro-nano channel networks exist inside plant tissues and between each cell.

[0003] Obviously, to realize the high-value utilization of plant materials, efficient disassembly and aggregation technology needs to be developed, and biomass materials of different shapes need to be processed into micron-sized plant fiber material raw materials with uniform morphology and size, or further disassembled into water-soluble or oil-soluble single biological macromolecular nanomaterials. Separation of cellulose, hemicellulose, and lignin for further modification into water-soluble or oil-soluble products is a research hotspot in the development and utilization of biomass. Cellulose sulfate monoester salt and lignin sulfonate are the most promising water-soluble biological macromolecular raw materials. They not only have the characteristics of high molecular weight and excellent water solubility, but also have pseudofluid characteristics, shear resistance, negative charge, suspension stability, film-forming property, and other properties, and have great application prospects in water retention, soil conditioning, water-soluble fertilizer, coating, oil and gas drilling engineering, food, cosmetics, cleaning products, capsule film sustained-release materials, degradable plastics, and other fields.

[0004] We first created a process for the sulfonated modification depolymerization of biomass fine powder such as microcrystalline fiber, raw pulp, straw powder, bamboo powder, shrub willow powder, starch, humic acid, shrimp and crab shell powder, etc. suspended in sulfur trioxide / 1,2-dichloroethane system to synthesize bio-based sulfonic acid. Bio-based sulfonic acid monoester or bio-based sulfonic acid or mixture is synthesized, and stable cellulose sulfonic acid monoester salt, cellulose sulfonic acid monoester salt and hemicellulose sulfonic acid monoester salt and lignin sulfonic acid monoester salt and lignin sulfonic acid salt mixture, starch sulfonic acid monoester salt, humic acid sulfonic acid salt, chitin sulfonic acid salt and other series of macromolecular bio-based sulfonated substances with good water solubility are obtained by neutralization with ammonia, lime, carbide slag, cement, sodium hydroxide or potassium hydroxide, etc. The raw material and product library of water-soluble polymers are greatly enriched. This major breakthrough in biomass disassembly and fractional utilization process has solved the industry problem of low-cost water-soluble and maintaining the structure of biological macromolecules, and has realized the breakthrough of the key node and root technology of biomass industry chain. However, the original process requires that the particle size of the biomass raw material is as fine as possible, even if the particle size of 300 mesh or so, the conversion rate is only 70%, and there are problems such as easy flying temperature in the reaction process, black material and material agglomeration sticking wall, etc. Energy saving and consumption reduction and process optimization to improve the conversion rate are still needed. SUMMARY

[0005] Improving the accessibility between reactants is the basic mass transfer requirement of chemical reaction, and it is also a major processing problem faced by biomass raw material derivatization. Obviously, the finer the raw material, the better the accessibility, the higher the conversion rate, but the greater the energy consumption. The previous sulfonation reaction experiment results show that the conversion rate of 30 mesh shrub or willow coarse powder in the suspended sulfur trioxide / 1,2-dichloroethane system is only about 40%, while the sulfonation and dissolution conversion rate of 300 mesh shrub and willow fine powder is about 70%, but the energy consumption increases by at least more than 9 times, and about one third of the raw material is not converted. Therefore, further improving the sulfonation and dissolution conversion rate of biomass, shortening the reaction time, avoiding carbonization and dehydration and agglomeration in the reaction process is the direction of technological research and development to promote the industrialization of the process and further reduce the production cost.

[0006] To solve the above technical problems, the present application provides a process for preparing bio-based sulfonate by "tidal" reaction of coarse particle biomass powder, which is as follows:

[0007] The biomass material is put into a closed container, the air is pumped out to a vacuum degree substantially unchanged, and SO3 / 1,2-dichloroethane solution is put in under mixing and stirring, the system is kept mixed, the solid material is completely soaked in the solution, and the reaction is carried out for a period of time, namely, soaking reaction, then the solution is separated, and the solid material is allowed to continue to react without solution for a period of time, namely, separated solution and reacted again, that is, through "vacuum-pumping, soaking reaction-separation solution and reaction again" similar "tide" circulation reaction 1-3 times, after the reaction is completed, 1,2-dichloroethane and sulfur trioxide are removed, and the base is neutralized to obtain a bio-based sulfonate.

[0008] Preferably, in the above method, the soaking reaction temperature is not higher than 35℃, the soaking reaction time is 5min-20min, the SO3 concentration in the SO3 / 1,2-dichloroethane solution is 2-6mol / L, the mass ratio of biomass to SO3 is 1:(0.4-1.2), the separation solution and reaction time is 10-15min, and the separation solution and reaction temperature is 0℃-60℃.

[0009] Preferably, in the above method, the "tide" reaction is 2-3 times, the soaking reaction temperature is 10-35℃, the SO3 concentration in the SO3 / 1,2-dichloroethane solution is 3-5mol / L, the mass ratio of biomass to SO3 is 1:0.9, and the separation solution and reaction temperature is 35℃-55℃.

[0010] Preferably, in the above method, the soaking reaction temperature is room temperature or low temperature, and the soaking time is 10min.

[0011] Preferably, in the above method, the temperature for removing 1,2-dichloroethane and sulfur trioxide is 40-50℃, and the solution obtained by removing 1,2-dichloroethane and sulfur trioxide is adjusted in concentration and recycled.

[0012] Preferably, in the above method, the solid obtained by removing 1,2-dichloroethane and sulfur trioxide is used as a bio-based sulfonic acid product, or is neutralized with a base to obtain a bio-based sulfonate directly as a product or is dried to obtain a bio-based sulfonate dry product.

[0013] Preferably, in the above method, the biomass material is put into a closed container in an intermittent or continuous manner, and the biomass material has a water content of less than 2%, preferably a water content of less than 1%.

[0014] Preferably, in the above method, the biomass material is any plant raw material, preferably one or more of bamboo, straw, shrub, sand willow, bleached pulp, cotton, natural color bamboo pulp, wood, etc., and the biomass material has one or more of the shapes of sheet, block, powder, silk, pulp, etc., and the size is suitable for being put into a closed container.

[0015] Preferably, in the above method, the biomass material is a powdered biomass material, that is, a biomass powder material, and the biomass powder material has a fineness of 10-100 mesh, preferably, the biomass powder material has a fineness of 20-40 mesh.

[0016] The experimental results of the optimized process conditions show that after 2-3 times of "vacuum extraction (emptying the gas in the capillary network) - rising (soaking reaction, soaking, supplementing reaction solution) - falling (separating the solution for reaction, eliminating liquid seal, vacuum extraction, emptying the material in the capillary network)", the conversion rate of 30 mesh biomass particles can be increased from about 45% of the control to about 90%, which is about 30% higher than the conversion rate of 300 mesh. The process method solves the problems of low conversion rate of coarse particles, low conversion efficiency and long sulfonation time of the original process. Through 2-3 times of similar "tidal" periodic reactions of simple vacuum extraction, liquid material soaking for about 10 minutes, and then separating the liquid material and reacting for another 10 minutes, not only the solvent and unreacted sulfur trioxide raw material can be recycled and reused, but also the conversion rate of the raw material can be greatly improved. The degree of substitution of the bio-based sulfonate product is about 0.8-1.0, which can be used in cement water reducing agent, asphalt modifier, desert management green polymer water retaining agent, water-soluble fertilizer, sticky thickening agent, surfactant, soil conditioner and other wide fields.

[0017] As shown in the accompanying drawings Figure 1 The plant tissue has very rich natural capillary network (similar to corrugated paper), and the gas or solution is restricted in and out due to capillary effect and surface tension. The larger the size of the biomass raw material, the more difficult the mass transfer. Therefore, it is crucial to use the natural micro-nano channel network of the biomass raw material to transport the raw material smoothly and break through the mass transfer resistance of the capillary effect and surface tension of the biomass. We found that the "tidal method" of "rising-falling" by circulating and vacuum extraction or solvent vapor to remove air or material in the capillary network can solve the mass transfer problem of biomass, and well overcome the problems of difficult impregnation and penetration of materials into the interior of biomass, difficult removal of materials in the interior of biomass, and serious influence of capillary effect and surface tension on mass transfer, reaction efficiency and conversion rate. The following will be illustrated in combination with two typical reactions.

[0018] The sulfonation process of biomass particles suspended in SO3 / DCE (1,2-dichloroethane) solvent system can be observed, and it can be observed that the liquid reactant mainly infiltrates and distributes on the surface of the particles. The gas present in the capillary network of the particles or the resistance to the entry of the liquid causes the reactant to have difficulty entering the capillary, and even if it enters part of the area in the capillary network, the reacted material is difficult to discharge due to the immersion of the liquid seal of the gasification solvent and the reacted material, which seriously hinders the penetration of the fresh reaction liquid, requires a long concentration balance time, and results in low conversion rate and long reaction time. Obviously, it is more difficult for the solid material to continue to react in the liquid phase, and it is more difficult for the material to be discharged from the capillary network by vacuumizing or using the reaction heat, and it can effectively avoid local overheating, which is beneficial to the entry of the new liquid reaction material into the capillary network of the empty coarse particle solid material, and significantly improves the reaction efficiency and conversion rate. The use of coarse particle material can not only greatly reduce the investment and energy consumption of the crushing equipment, but also can control the reaction speed and avoid agglomeration.

[0019] The SO3 dispersity, concentration, reaction time and desolventization temperature have a great influence on the dissolution conversion rate of the bio-based sulfonate, but the control step that influences the dissolution conversion rate of the bio-based sulfonate is the penetration mass transfer efficiency of the biomass particle. In the early stage, most of the air can be removed by vacuumizing, and the capillary structure under negative pressure is more conducive to the penetration of the liquid material. The sulfur trioxide in the SO3 / 1,2-dichloroethane material liquid will react with the primary alcohol group of the biomass macromolecule on the surface to generate a monoester, and the sulfonate negative ion and hydrogen positive ion are dissociated. Under the double action of the same electrostatic repulsion and the opposite electrostatic attraction, the macromolecules in the crystalline and non-crystalline regions will tend to be as far away from the surface as possible, thereby exposing more new surfaces that can continue to react, until the system is completely reacted. This process is like "ants gnawing bones", and the concentration of sulfur trioxide and the accessibility of the material are the key to the completion of this reaction.

[0020] Through the exploration of the dissolution conversion rate of biomass by different SO3 / 1,2-dichloroethane solution concentrations and vacuumizing time, "rise-fall" interval reaction time, we obtained the optimized reaction process conditions.

[0021] The process has the advantages of simple process, high reaction efficiency and conversion rate, mild reaction conditions, realization of high-value utilization of biomass, especially straw, recycling of raw materials and solvents involved in the reaction, realization of clean production, low investment and production cost, rich raw material sources, wide product application range and great development prospects. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Plant morphology and internal structure diagram of different sizes

[0023] Figure 2Infrared spectrum of the biosourced sodium sulfonate prepared after the vacuum "tidal" sulfonation reaction

[0024] Figure 3 Residue chart of Caragana, Salix and bamboo after desolventizing at 4 mol / L SO3 concentration and 43℃, 60℃

[0025] Figure 4 Residue chart of bamboo after the sulfonation reaction with different vacuum "tidal" time and intermittent time DETAILED DESCRIPTION

[0026] The present application can be further illustrated by the following non-limiting examples. The following examples reflect the implementation effects under different process conditions, different soaking times, different vacuum times, vacuum times, intermittent times after vacuum, and desolventizing temperatures after reaction completion.

[0027] Preparation example:

[0028] The tidal method for preparing the biosourced sodium sulfonate is as follows:

[0029] 1. Preparation of biomass material raw materials

[0030] The biomass Caragana branches, Salix branches and bamboo blocks were cut, dried, crushed, sieved and dried to 1% moisture for standby.

[0031] 2. Preparation of SO3 solution

[0032] The solid or liquid SO3 was added to 1,2-dichloroethane and stirred to fully dissolve and mix, to prepare the required SO3 concentration of SO3 / 1,2-dichloroethane solvent.

[0033] 3. Sulfonation of biomass raw materials

[0034] The crushed and dried Caragana branch powder, Salix branch powder and bamboo powder with water content less than 1% were added to the reactor, vacuumed to remove air for 10 minutes, and then the SO3 / 1,2-dichloroethane solvent was slowly added under stirring, soaked for 10 minutes, and then the solvent was extracted. After the solution was separated and reacted for 10 minutes, vacuum was applied (this process is called a tidal reaction). According to the need, repeated operation was performed, that is, the vacuumed solid reaction product was added again to the SO3 / 1,2-dichloroethane solvent, soaked for 10 minutes, and then the solvent was extracted. After the solution was separated and reacted for 10 minutes, vacuum was applied, and this process was repeated for multiple tidal reactions. After the last tidal reaction removed the unreacted SO3 and 1,2-dichloroethane from the reaction product, it can be used as an intermediate product or subjected to further neutralization to adjust the pH to 7 to 8, and the residual 1,2-dichloroethane in the solid-liquid mixture was evaporated. The collected filtrate was a biosourced sodium sulfonate aqueous solution, which can also be spray dried to obtain a powder product.

[0035] 4. Product characterization

[0036] Because the biomass material is not soluble in water, the bio-based sulfonate is soluble in water, so the dissolution conversion rate of the biomass material is calculated by weight loss method. The relevant inspection and analysis method of the product is shown in Table 1.

[0037] Table 1 Product analysis items and analysis methods

[0038] Analysis item Analysis method Functional group analysis FT-IR Biomass dissolution conversion rate Gravimetric method Average degree of substitution Elemental analysis method Morphology characterization SEM

[0039] Example 1

[0040] The bio-based sulfonate method operation is prepared according to the tidal method described in the preparation example and the conventional method. The conventional bio-based sulfonate operation method is: keeping the reaction temperature at 30℃, the mass of each reaction raw material is 5g, the mass ratio of the reaction raw material to SO3 is 1:0.9, and the reaction time is 3h. The tidal method reaction condition is: 30-40 mesh of shrub willow branch powder, sand willow branch powder, and bamboo powder are used as biomass raw materials by vacuum "tidal method", vacuum for 10min, soak for 10min after vacuum, separate the solution and vacuum for 10min. Repeat the "tidal" for 2-3 times.

[0041] This example carries out the influence of SO3 concentration in SO3 / 1,2-dichloroethane solution and the dissolution conversion rate of biomass after the reaction is completed on the dissolution conversion rate of biomass, and the comparison and evaluation of different soaking times of sulfonation process on the dissolution conversion rate of biomass. Under different SO3 concentrations, the related experiments after each "vacuum" tidal and the control experiment results are shown in Tables 2, 3, 4, 5, 6, 7, 8 and 9.

[0042] Table 2 Influence of different sulfonation processes on the dissolution conversion rate of 30-40 mesh shrub willow branch powder, sand willow branch powder and bamboo powder

[0043]

[0044] The "dissolution conversion rate" in the above description and Table 2 is the conversion rate of soluble bio-based sulfonate, which can directly reflect the yield of biomass sulfonate (the same below).

[0045] It can be seen that the "tidal method" has a very significant effect on the yield of biomass, and vacuum can easily empty the material in the capillary network of powder particles, which can greatly improve the conversion rate; the difference in conversion rate of different plant raw materials is also significant.

[0046] Table 3 Influence of SO3 concentration in vacuum "tidal" method on the dissolution conversion rate of shrub willow branch powder, sand willow branch powder and bamboo powder

[0047]

[0048]

[0049] From Table 3, it can be seen that the conversion rate of the three raw materials is the highest when the SO3 concentration is about 4M.

[0050] Table 4 Influence of desolventization at different temperatures on the dissolution conversion rate of the sulfonated Caragana, Salix and bamboo powder

[0051]

[0052] From the results in Table 4, it can be seen that the desolventization temperature has a great influence on the conversion rate of the raw material. Increasing the desolventization temperature can intensify carbonization dehydration and condensation. The conversion rate can be easily ensured by taking the way of rapid desolventization at a lower temperature (about 40°C) under reduced pressure.

[0053] Example 2

[0054] According to the optimal SO3 concentration of 4 mol / L and the desolventization temperature of about 43°C, further exploration was made on the influence of different vacuum pumping times and intermittent times after vacuum pumping on the sulfonated dissolution conversion rate of the biomass by using the bamboo powder with the lowest conversion rate. The relevant experimental and control experimental results are shown in Table 5.

[0055] Table 5 Influence of vacuum "tide" time and intermittent time on the sulfonated dissolution conversion rate of the bamboo powder

[0056]

[0057]

[0058] It can be seen that the optimal time for vacuum and separation of the solution and reaction is about 10 minutes. Too long or too short time will affect the conversion rate.

[0059] Example 3

[0060] According to the reaction conditions in Example 1, the influence of three vacuum tides on the sulfonated dissolution conversion rate of the bamboo biomass was evaluated by pumping out the remaining SO3 / 1,2-dichloroethane solution after each vacuum pumping and soaking, and then soaking with new SO3 / 1,2-dichloroethane solution with a concentration of 4 mol / L. The relevant experimental and control experimental results are shown in Table 6.

[0061] Table 6 Influence of the same reactant concentration in three vacuum "tides" on the sulfonated dissolution conversion rate of Caragana, Salix and bamboo

[0062]

[0063] Obviously, the process conditions of vacuum "tide" before each soaking and emptying the capillary network can indeed improve the conversion rate of the bamboo powder compared with other conditions.

[0064] Example 4

[0065] The reaction conditions of Example 1 were used in a 4 mol / L SO3 / DCE sulfonation system, and the mass of total SO3 input was 4.5 g. The volume, concentration, mass of residual SO3 after each "vacuum tide" was completed, and the percentage of residual SO3 amount to total SO3 input were determined. The relevant experimental and control experimental analysis results are shown in Tables 7 and 8.

[0066] Table 7 Change in residual SO3 amount after each vacuum "tide" at a 4 mol / L SO3 / DCE concentration

[0067]

[0068]

[0069] Table 8 Percentage of residual SO3 amount to total SO3 input after each vacuum "tide" at a 4 mol / L SO3 / DCE concentration

[0070]

[0071] It can be seen that the adsorption of reactants by the three raw materials is very different. After the first tide reaction, Salix, Salix, and bamboo reacted and adsorbed three-thirds, two-thirds, and one-third of sulfur trioxide, respectively. After the second tide reaction, Salix, Salix, and bamboo reacted and adsorbed about 82%, 76%, and 68% of sulfur trioxide, respectively. After the third tide reaction, Salix, Salix, and bamboo reacted and adsorbed about 89%, 83%, and 76% of sulfur trioxide, respectively. Obviously, due to the large difference in the compactness of the three materials, it caused a large difference in the adsorption of reactants and conversion rate.

[0072] Table 9 Elemental analysis of Salix, Salix, and bamboo-based sodium sulfonate

[0073] Sample C％ H％ N％ S％ DS Biobased sodium sulfonate of caragana 24.73 4.87 0.82 9.53 0.88 Biobased sodium sulfonate of sand willow 24.31 4.53 0.66 9.07 0.84 Biobased sodium sulfonate of bamboo 23.98 4.15 0.19 8.62 0.81

[0074] As can be seen from Table 9, since the Salix powder has the largest amount of adsorbed reactant material, the degree of substitution of the obtained bio-based sodium sulfonate is also the highest.

Claims

1. A process for preparing bio-based sulfonate by fast and efficient sulfonation of coarse granular biomass powder through "tidal" reaction, the process is as follows: biomass material is put into a closed container, vacuum is extracted to remove air to a constant vacuum degree, SO3 / 1,2-dichloroethane solution is put in under mixing and stirring, the system is kept fully mixed, the solid material is completely immersed in the solution for a period of time, namely soaking reaction, then the solution is separated, and the solid material continues to react without solution for a period of time, namely separated solution re-reaction, that is, through "vacuum extraction-soaking reaction-separated solution re-reaction" similar "tidal" cycle reaction 1-3 times, after the reaction is completed, 1,2-dichloroethane and sulfur trioxide are removed, and the bio-based sulfonate is obtained by neutralization with alkali; the reaction time of the solid material completely immersed in the solution is 5 minutes to 20 minutes; wherein the reaction time of the solid material continuing to react without solution is 10-15 minutes. The soaking reaction temperature is not higher than 35℃, the soaking reaction time is 5min-20min, the SO3 concentration in the SO3 / 1,2-dichloroethane solution is 2-6mol / L, the mass ratio of biomass to SO3 is 1:(0.4-1.2), the separated solution re-reaction time is 10-15 minutes, and the separated solution re-reaction temperature is 0℃-60℃.

2. The process according to claim 1, characterized in that The "tidal" reaction is 2-3 times, the soaking reaction temperature is 10-35℃, the SO3 concentration in the SO3 / 1,2-dichloroethane solution is 3-5moL / L, the mass ratio of biomass to SO3 is 1:0.9, and the separated solution re-reaction temperature is 35℃-55℃.

3. The process of claim 2, wherein The soaking reaction temperature is room temperature or low temperature of 0℃, and the soaking time is 10min.

4. The process of claim 1, wherein The temperature for removing 1,2-dichloroethane and sulfur trioxide is 40-50℃, and the solution obtained by removing 1,2-dichloroethane and sulfur trioxide is adjusted in concentration and recycled.

5. The process of claim 1, wherein The solid obtained by removing 1,2-dichloroethane and sulfur trioxide is used as a bio-based sulfonic acid product, or is neutralized with alkali to obtain a bio-based sulfonate directly as a product or is dried to obtain a bio-based sulfonate dry product.

6. The process of claim 1, wherein The way of putting the biomass material into the closed container is intermittent or continuous, and the biomass material has a water content of less than 2%.

7. The process of claim 1, wherein The biomass material has a water content of less than 1%.

8. The process of claim 7, wherein The biomass material is any plant raw material.

9. The process of claim 1, wherein The biomass material is one or more of bamboo, straw, shrub, sand willow, bleached pulp, cotton, natural color bamboo pulp, and wood, and the shape of the biomass material is one or more of sheet, block, powder, silk, and pulp, and the size is capable of being put into the closed container.

10. The process of claim 9, wherein The biomass material is a powder biomass material, that is, a biomass powder material, and the fineness of the biomass powder material is 10-100 mesh.

11. The process of claim 10, wherein The fineness of the biomass powder material is 20-40 mesh.

12. The process of claim 11, wherein ​

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