Production device and production method of super-superior furfural

Abstract

The production device comprises a crusher, an acid mixing tank, a hydrolysis kettle, a filter, a condenser, a buffer tank, a light component removal tower, a heavy component removal tower, an aldehyde-water separator, a decolorizing tank, an intermediate buffer tank, a neutralizing tank, a dehydrating tower, a rectifying tower and a refined aldehyde storage tank which are connected in sequence. The production method specifically comprises the following steps: (1) crushing a plant fiber material, and mixing the crushed plant fiber material with a dilute sulfuric acid solution; (2) hydrolysis reaction, filtration, condensation, light component removal, heavy component removal, aldehyde-water separation and adsorption decolorization; and (3) mixing with alkali liquor, dehydrating and rectifying. The method provided by the invention has the advantages of high product purity, good separation effect, low operation energy consumption, environmental protection, sustainability, realization of continuous operation, low production device equipment investment, simple production process operation, easy reaction control, full utilization of furfural wake fraction, and high economic benefit, and accords with the market prospect.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity chemicals, and more particularly to a production device and a production method of premium furfural. Background Art

[0002] Furfural is a heterocyclic aldehyde with active double bonds. Corn cobs, rice husks and cottonseed husks can all be used as raw materials for the production of furfural, which are abundant and cheap. Furfural and its derivatives are widely used. The main functions of furfural are reflected in the chemical industry, agriculture and medicine. It can be used as a solvent, intermediate and pharmaceutical raw material, and has antiseptic and antibacterial properties, which makes it irreplaceable. In recent years, with the rapid development of these industries, the demand for furfural market has also shown a rapid growth trend. The raw materials for the production of furfural are mainly agricultural waste, so its production process has the advantages of environmental protection and sustainability. By recycling these wastes, not only can environmental pollution be reduced, but also the effective utilization of resources can be achieved. Therefore, furfural has a wide range of applications and important market value. Its production process is complex but sustainable, and the raw materials are widely sourced and environmentally friendly. With the advancement of science and technology and the continuous development of the market, the application field of furfural will be wider and the market prospects will be broader.

[0003] At present, the furfural production process at home and abroad is mainly divided into a one-step production method and a two-step production method. Among them, the one-step production method is that the two-step reaction of pentosan hydrolysis and pentose dehydration to produce furfural is completed in the same hydrolysis pot at one time; the two-step production method is that pentosan is first hydrolyzed at about 100°C to produce pentose, and then the pentose is dehydrated and cyclized to produce furfural under higher temperature conditions. One-step production has been widely used in the furfural industry because of its low equipment investment, simple operation, and easy reaction control; while the two-step production process is relatively complicated, the equipment investment is high, and the second step dehydration process conditions are not very mature, and it has not been put into practical use in industrial production. CN201910237443 proposes a method for preparing furfural, which mixes plant raw materials with organic acids, introduces hemicellulose solution above the reactor during the reaction, and feeds acetic acid vapor below the reactor, so that the sugar solution and acetic acid vapor are in countercurrent contact, and the furfural vapor is released semi-continuously in batches, but this method cannot achieve continuous operation, and a large amount of impurities are introduced during the production process, and there is no subsequent purification and refining.

[0004] Therefore, in order to meet the needs of the market, it is urgent to develop a new process that has high purity, low energy consumption, is green and environmentally friendly, and can continuously and stably produce premium furfural on a large scale. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a production device and a production method of premium furfural to solve the deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A production device for premium furfural comprises a pulverizer, a mixed acid tank, a hydrolysis kettle, a filter, a condenser, a buffer tank, a light removal tower, a heavy removal tower, an aldehyde-water separator, a decolorization tank, an intermediate buffer tank, a neutralization tank, a dehydration tower, a distillation tower and a refined aldehyde storage tank, which are connected in sequence;

[0008] Among them, the light removal tower, heavy removal tower and dehydration tower are connected to the buffer tank respectively, the aldehyde-water separator is connected to the light removal tower, and the distillation tower is connected to the heavy removal tower;

[0009] The tops of the light-removal tower, heavy-removal tower, dehydration tower and distillation tower are all connected with coolers, and the bottoms of the towers are all connected with reboilers.

[0010] Furthermore, the above-mentioned light-removal tower, heavy-removal tower, intermediate buffer tank, neutralization tank, dehydration tower, distillation tower and refined aldehyde storage tank are all maintained in vacuum operation.

[0011] A method for producing premium furfural, using the above-mentioned production device for premium furfural, specifically comprises the following steps:

[0012] (1) First, the plant fiber material is fed into a pulverizer for pulverization to obtain plant fiber material particles, and then fed into a mixed acid tank through a screw conveyor, and mixed with a dilute sulfuric acid solution in the mixed acid tank to obtain a solid-liquid mixture;

[0013] (2) The solid-liquid mixture is sent to the hydrolysis kettle for hydrolysis reaction. The obtained furfural gas is first filtered through a filter, then condensed through a condenser, and then enters a buffer tank, and then sent to a lightness removal tower; the top vapor of the lightness removal tower is condensed through a top cooler, and part of it is refluxed, and part of it is sent back to the buffer tank, and the bottom liquid of the lightness removal tower is reboiled in a kettle reboiler, and part of it is refluxed, and part of it is sent to the de-weight removal tower; the top mixed liquid (aldehyde-water azeotrope) of the de-weight removal tower is condensed through a top cooler, and then sent to an aldehyde-water separator, and the bottom liquid of the de-weight removal tower is reboiled in a kettle reboiler, and part of it is refluxed, and part of it is sent back to the buffer tank; the liquid phase in the aldehyde-water separator is separated into an aldehyde layer and a water layer, and the aldehyde layer is sent to a decolorization tank for adsorption decolorization, and the water layer is sent back to the lightness removal tower for further distillation;

[0014] (3) The crude aldehyde liquid after decolorization in the decolorization tank is sent to the neutralization tank through the intermediate buffer tank, mixed with the alkali solution in the neutralization tank, and then sent to the dehydration tower; the top steam of the dehydration tower is condensed by the top cooler and partially refluxed, and partially sent back to the buffer tank, and the bottom liquid of the dehydration tower is reboiled in the kettle reboiler and partially refluxed, and partially sent to the distillation tower; the top steam of the distillation tower is condensed by the top cooler to obtain the premium furfural, which is sent to the refined aldehyde storage tank, and the bottom liquid of the distillation tower is reboiled in the kettle reboiler and partially refluxed, and partially sent back to the deweighting tower for further distillation.

[0015] Furthermore, in the above step (1), the plant fiber material is at least one of corn cobs, rice husks, wood waste and wheat straw, preferably corn cobs; the particle size of the plant fiber material particles is 10-30 mm; the mass fraction of the dilute sulfuric acid solution is 3%-8%, and the amount used is 40%-60% of the mass of the plant fiber material particles.

[0016] A further beneficial effect of adopting the above method is that the raw materials selected in the present invention are plant raw materials, which have little impact on the environment and high safety performance.

[0017] Furthermore, in the above step (2), the hydrolysis kettles are connected in parallel in two or more groups, each group is composed of two or more hydrolysis kettles connected in series; during the hydrolysis reaction, steam is introduced into the hydrolysis kettle, the operating pressure is 0.35~0.9 MPa, the temperature is 130~230℃, and the time is 1~6 hours. The furfural gas obtained by the reaction in the hydrolysis kettle should be blown out immediately with steam, and a detection device is set on the hydrolysis kettle. When the amount of aldehyde output is high, the steam valve is opened wide, and when the amount of aldehyde output is small, the steam valve is opened small.

[0018] A further beneficial effect of the above method is that the hydrolysis kettle selected in the present invention can realize continuous large-scale operation.

[0019] Furthermore, in the above step (2), the operating temperature of the top of the lightness removal tower is 60-75°C, the operating temperature of the bottom of the tower is 80-100°C, and the operating pressure is 0.1-0.2 MPa.

[0020] Furthermore, in the above step (2), the bottom of the deweighting tower is indirectly heated by steam, the operating temperature of the top of the tower is 80-105°C, the operating temperature of the bottom of the tower is 95-110°C, the operating pressure is 0.1-0.2 MPa, and the mixed liquid at the top of the tower is condensed to below 56°C through a top cooler; the material used for adsorption decolorization is activated carbon or resin.

[0021] Furthermore, in the above step (3), the intermediate buffer tank is filled with nitrogen to seal the decolorized crude aldehyde liquid; the refined aldehyde storage tank is filled with nitrogen to seal the premium furfural; the alkali solution is at least one of Na2CO3 solution, CaO solution, NaOH solution and NaHCO3 solution, preferably Na2CO3, with a mass fraction of 10% to 15%, and the amount used is 3% to 5% of the mass of the crude aldehyde liquid.

[0022] A further beneficial effect of the above method is that the purpose of adding the alkali solution is to neutralize a small amount of sulfuric acid in the crude aldehyde solution and a small amount of acetic acid produced during the hydrolysis process.

[0023] Furthermore, in the above step (3), the dehydration tower adopts a temperature-raising and pressure-reducing operation, an air valve is provided at the bottom of the tower, and the air valve is opened during operation for air stirring, and the tower top temperature is controlled to rise to 80-105°C, the tower bottom temperature is 90-120°C, and the operating pressure is 0.1-0.2 MPa. When the temperature and vacuum degree are stable, distillation is continued for 10-20 minutes.

[0024] Furthermore, in the above step (3), the distillation tower adopts a double-filled tower in parallel for refining, the filler is the BH type high-efficiency filler developed by Beijing University of Chemical Technology, the method is a vacuum distillation method or a steam distillation method, the operating temperature of the tower top is 50~100℃, the operating temperature of the tower bottom is 90~115℃, the operating pressure is 0.1~0.2 MPa, the aldehyde sludge is discharged once every 3 refining kettles, and the tower is washed once every 4 refining kettles.

[0025] A further beneficial effect of the above method is that the dual-tower parallel refining can ensure continuous production.

[0026] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The present invention adopts multi-tower distillation, with simplified process steps, high product purity, high separation efficiency, few impurities, and extremely high market potential.

[0028] 2. The present invention adopts a method of connecting multiple groups of hydrolysis kettles in parallel, connecting multiple hydrolysis kettles in series, and refining with double distillation towers in parallel to ensure the sustainability of the operation, which can realize large-scale stable and continuous operation, support continuous and automated production processes, accurately meet the stringent needs of the high-end market, and has broad market prospects.

[0029] 3. The production process of the present invention contains more reflux, fully recycles and utilizes waste liquid, realizes the maximum recycling of resources, not only optimizes energy allocation, but also significantly improves energy efficiency, and achieves the green and energy-saving production goal.

[0030] 4. The product of the present invention has high purity, good separation effect, low operating energy consumption, environmental protection and sustainability, can achieve continuous operation, and requires little investment in production equipment, simple production process operation, easy reaction control, full utilization of furfural tail stream, high economic benefits, and meets market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 The schematic diagram of the structure of the production device of the premium grade furfural of the present invention.

[0033] Among them, 1-crusher, 2-mixed acid tank, 3-hydrolysis kettle, 4-filter, 5-condenser, 6-buffer tank, 7-light removal tower, 8-heavy removal tower, 9-aldehyde-water separator, 10-decolorization tank, 11-intermediate buffer tank, 12-neutralization tank, 13-dehydration tower, 14-distillation tower, 15-refined aldehyde storage tank. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] Example 1

[0040] The production equipment of premium furfural, such as Figure 1 As shown, it includes a pulverizer 1, a mixed acid tank 2, a hydrolysis kettle 3, a filter 4, a condenser 5, a buffer tank 6, a light removal tower 7, a heavy removal tower 8, an aldehyde-water separator 9, a decolorization tank 10, an intermediate buffer tank 11, a neutralization tank 12, a dehydration tower 13, a distillation tower 14 and a refined aldehyde storage tank 15 which are connected in sequence;

[0041] Among them, the light removal tower 7, the heavy removal tower 8 and the dehydration tower 13 are respectively connected to the buffer tank 6, the aldehyde-water separator 9 is connected to the light removal tower 7, and the distillation tower 14 is connected to the heavy removal tower 8;

[0042] The tops of the light removal tower 7, the heavy removal tower 8, the dehydration tower 13 and the distillation tower 14 are all connected to coolers, and the bottoms of the towers are all connected to reboilers;

[0043] The light-removing tower 7, heavy-removing tower 8, intermediate buffer tank 11, neutralization tank 12, dehydration tower 13, distillation tower 14 and refined aldehyde storage tank 15 are all maintained in vacuum operation.

[0044] Example 2

[0045] The production method of premium furfural adopts the production device of premium furfural in Example 1, and specifically comprises the following steps:

[0046] (1) First, the corn cob is fed into a pulverizer 1 for pulverization to obtain plant fiber material particles of 10 mm, and then fed into a mixed acid tank 2 through a screw conveyor, and mixed with a 40% amount of a 3% by mass dilute sulfuric acid solution in the mixed acid tank 2 to obtain a solid-liquid mixture;

[0047] (2) The solid-liquid mixture is sent to the hydrolysis kettle 3 for hydrolysis reaction. The hydrolysis kettle 3 is composed of two groups connected in parallel, and each group consists of two hydrolysis kettles connected in series. Steam is introduced after sealing and feeding. The operating pressure is 0.49 MPa, the temperature is 145.79°C, and the time is 6 hours. The furfural gas generated after the hydrolysis reaction is blown out with steam, first filtered by the filter 4, then condensed by the condenser 5, and then enters the buffer tank 6, and then sent to the light removal tower 7;

[0048] The operating temperature of the top of the light removal tower 7 is 64.33°C, the operating temperature of the bottom is 83.54°C, and the operating pressure is 0.1MPa. The top vapor is condensed by the top cooler and partially refluxed, and partially sent back to the buffer tank 6 for redistillation. The bottom liquid of the light removal tower 7 is reboiled in the kettle reboiler, and partially refluxed, and partially sent to the heavy removal tower 8.

[0049] The bottom of the de-weighting tower 8 is indirectly heated by steam, the operating temperature of the top of the tower is 85.34°C, the operating temperature of the bottom of the tower is 100.41°C, the operating pressure is 0.15 MPa, the top mixed liquid is condensed to 45.38°C by the top cooler and then sent to the aldehyde-water separator 9, the bottom liquid of the de-weighting tower 8 is reboiled in the tower kettle reboiler and then partly refluxed and partly sent back to the buffer tank 6;

[0050] The liquid phase in the aldehyde-water separator 9 is separated into an aldehyde layer and a water layer. The aldehyde layer is sent to the decolorization tank 10 for activated carbon adsorption decolorization. The water layer contains 7% aldehyde and is sent back to the light removal tower 7 for further distillation.

[0051] (3) The crude aldehyde solution after decolorization in the decolorization tank 10 is sent to the neutralization tank 12 through the intermediate buffer tank 11. The intermediate buffer tank 11 is filled with nitrogen to seal the decolorized crude aldehyde solution. The crude aldehyde solution is mixed and stirred with a 3% dosage and a mass fraction of 10% Na2CO3 solution in the neutralization tank 12 for 10 minutes, and then allowed to stand for 10 minutes before being sent to the dehydration tower 13;

[0052] The dehydration tower 13 adopts the operation of temperature increase and pressure reduction. An air valve is set at the bottom of the tower. The air valve is opened during operation for air stirring. The tower top temperature is controlled to rise to 82.98°C, the tower bottom temperature is 97.87°C, and the operating pressure is 0.1 MPa. When the temperature and vacuum degree are stable, distillation is continued for 10 minutes. The tower top steam is condensed by the tower top cooler and partially refluxed and partially sent back to the buffer tank 6. The tower bottom liquid of the dehydration tower 13 is reboiled in the tower kettle reboiler and partially refluxed and partially sent to the distillation tower 14.

[0053] The distillation tower 14 adopts a double-filled tower in parallel for refining, and the filler is BH type high-efficiency filler. The method is vacuum distillation. The operating temperature of the top of the tower is 65.7°C, the operating temperature of the bottom of the tower is 102.6°C, and the operating pressure is 0.1 MPa. The aldehyde sludge is discharged once every 3 kettles of refining, and the tower is washed once every 4 kettles of refining. The top steam is condensed by the top cooler to obtain the premium grade furfural, which is sent to the refined aldehyde storage tank 15. Nitrogen is filled into the refined aldehyde storage tank 15 to seal the premium grade furfural. The bottom liquid of the distillation tower 14 is reboiled in the bottom reboiler and then partially refluxed and partially sent back to the deweighting tower 8 for further distillation.

[0054] Example 3

[0055] The production method of premium furfural adopts the production device of premium furfural in Example 1, and specifically comprises the following steps:

[0056] (1) First, the corn cob is fed into a pulverizer 1 for pulverization to obtain plant fiber material particles of 30 mm, and then fed into a mixed acid tank 2 through a screw conveyor, and mixed with a 40% amount of a dilute sulfuric acid solution with a mass fraction of 8% in the mixed acid tank 2 to obtain a solid-liquid mixture;

[0057] (2) The solid-liquid mixture is sent to the hydrolysis kettle 3 for hydrolysis reaction. The hydrolysis kettle 3 is composed of two groups connected in parallel, and each group consists of two hydrolysis kettles connected in series. Steam is introduced after sealing and feeding. The operating pressure is 0.89 MPa, the temperature is 189.2°C, and the time is 3 h. The furfural gas generated after the hydrolysis reaction is blown out with steam, first filtered by the filter 4, then condensed by the condenser 5, and then enters the buffer tank 6, and then sent to the light removal tower 7;

[0058] The operating temperature of the top of the light removal tower 7 is 72.43°C, the operating temperature of the bottom is 95.22°C, and the operating pressure is 0.1MPa. The top vapor is condensed by the top cooler and partially refluxed, and partially sent back to the buffer tank 6 for redistillation. The bottom liquid of the light removal tower 7 is reboiled in the kettle reboiler, and partially refluxed, and partially sent to the heavy removal tower 8.

[0059] The bottom of the de-weighting tower 8 is indirectly heated by steam, the operating temperature of the top of the tower is 95.1°C, the operating temperature of the bottom of the tower is 109.57°C, the operating pressure is 0.2 MPa, the top mixed liquid is condensed to 55.4°C by the top cooler and then sent to the aldehyde-water separator 9, the bottom liquid of the de-weighting tower 8 is reboiled in the tower kettle reboiler and then partially refluxed and partially sent back to the buffer tank 6;

[0060] The liquid phase in the aldehyde-water separator 9 is separated into an aldehyde layer and a water layer. The aldehyde layer is sent to the decolorization tank 10 for activated carbon adsorption decolorization. The water layer contains 8.5% aldehyde and is sent back to the light removal tower 7 for further distillation.

[0061] (3) The crude aldehyde solution after decolorization in the decolorization tank 10 is sent to the neutralization tank 12 through the intermediate buffer tank 11. The intermediate buffer tank 11 is filled with nitrogen to seal the decolorized crude aldehyde solution. The crude aldehyde solution is mixed and stirred with a 3% dosage and a mass fraction of 10% Na2CO3 solution in the neutralization tank 12 for 10 minutes, and then allowed to stand for 10 minutes before being sent to the dehydration tower 13;

[0062] The dehydration tower 13 adopts the operation of temperature increase and pressure reduction. An air valve is set at the bottom of the tower. The air valve is opened during operation for air stirring. The top temperature is controlled to rise to 97.35°C, the bottom temperature is 108.97°C, and the operating pressure is 0.12 MPa. When the temperature and vacuum degree are stable, distillation is continued for 10 minutes. The top steam is condensed by the top cooler and partially refluxed and partially sent back to the buffer tank 6. The bottom liquid of the dehydration tower 13 is reboiled in the tower kettle reboiler and partially refluxed and partially sent to the distillation tower 14.

[0063] The distillation tower 14 adopts a double-filled tower in parallel for refining, and the filler is BH type high-efficiency filler. The method is vacuum distillation. The operating temperature of the top of the tower is 91.3°C, the operating temperature of the bottom of the tower is 112.58°C, and the operating pressure is 0.15 MPa. The aldehyde sludge is discharged once every 3 kettles of refining, and the tower is washed once every 4 kettles of refining. The top steam is condensed by the top cooler to obtain the premium grade furfural, which is sent to the refined aldehyde storage tank 15. Nitrogen is filled in the refined aldehyde storage tank 15 to seal the premium grade furfural. The bottom liquid of the distillation tower 14 is reboiled in the bottom reboiler and then partially refluxed and partially sent back to the deweighting tower 8 for further distillation.

[0064] Comparative Example

[0065] The furfural product produced by a certain enterprise specifically includes the following steps:

[0066] (1) Wash and crush the corn cobs, add them into a hydrolysis pot, add formic acid, washing wastewater and waste acid filtrate, pressurize and heat to react, and hydrolyze the pentosan in the corn cobs into pentoses;

[0067] (2) After the hydrolysis is completed, the pentose solution is pressed to produce furfural. The pentose solution and the water produced in other stages enter the dehydration reactor and react for 2 hours to complete the dehydration cyclization of pentose and the distillation of crude furfural.

[0068] (3) The evaporated material is condensed and then passes through a primary distillation tower, a crude aldehyde phase separation tower, and a rectification tower in sequence to finally obtain the finished furfural.

[0069] Performance Testing

[0070] The furfural products obtained in the comparative example and Examples 2-3 were respectively observed for their appearance, and their moisture, acidity and purity were tested.

[0071] The results are shown in Table 1.

[0072] Table 1 Indexes of furfural products of comparative example and example 2-3

[0073] Quality indicators Comparative Example Example 2 Example 3 Appearance Slightly yellow colorless colorless Moisture 0.15% 0.03% 0.02% acidity 0.016 0.006 0.004 purity 98.5% 99.85% 99.9%

[0074] It can be seen from Table 1 that, compared with the comparative example, the furfural product of Example 2-3 has a lighter color, lower moisture and acidity, and has higher economic benefits.

[0075] The above experiments show that the product of the present invention has high purity, good separation effect, low operating energy consumption, is environmentally friendly and sustainable, can achieve continuous operation, and requires little investment in production equipment, simple production process operation, easy reaction control, full utilization of furfural tail stream, high economic benefit, and meets market prospects.

[0076] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A production device for premium furfural, characterized in that: It includes a pulverizer, a mixed acid tank, a hydrolysis kettle, a filter, a condenser, a buffer tank, a light removal tower, a heavy removal tower, an aldehyde-water separator, a decolorization tank, an intermediate buffer tank, a neutralization tank, a dehydration tower, a distillation tower and a refined aldehyde storage tank connected in sequence; The light-removing tower, the heavy-removing tower and the dehydration tower are respectively connected to the buffer tank, the aldehyde-water separator is connected to the light-removing tower, and the distillation tower is connected to the heavy-removing tower; The tops of the light-removing tower, the heavy-removing tower, the dehydration tower and the distillation tower are all connected with coolers, and the bottoms of the towers are all connected with reboilers.

2. A production device for premium furfural according to claim 1, characterized in that: The light-removing tower, the heavy-removing tower, the intermediate buffer tank, the neutralization tank, the dehydration tower, the distillation tower and the refined aldehyde storage tank are all maintained in vacuum operation.

3. A method for producing premium furfural, characterized in that: The production device of the premium furfural as claimed in claim 1 specifically comprises the following steps: (1) First, the plant fiber material is fed into a pulverizer for pulverization to obtain plant fiber material particles, and then fed into a mixed acid tank through a screw conveyor, and mixed with a dilute sulfuric acid solution in the mixed acid tank to obtain a solid-liquid mixture; (2) The solid-liquid mixture is sent to the hydrolysis kettle for hydrolysis reaction. The obtained furfural gas is first filtered through a filter, then condensed through a condenser, and then enters a buffer tank, and then sent to a lightness removal tower; the top vapor of the lightness removal tower is condensed through a top cooler, and part of it is refluxed, and part of it is sent back to the buffer tank, and the bottom liquid of the lightness removal tower is reboiled through a kettle reboiler, and part of it is refluxed, and part of it is sent to the heavy removal tower; the top mixed liquid of the heavy removal tower is condensed through a top cooler, and then sent to an aldehyde-water separator, and the bottom liquid of the heavy removal tower is reboiled through a kettle reboiler, and part of it is refluxed, and part of it is sent back to the buffer tank; the liquid phase in the aldehyde-water separator is separated into an aldehyde layer and a water layer, and the aldehyde layer is sent to a decolorization tank for adsorption decolorization, and the water layer is sent back to the lightness removal tower for further distillation; (3) The crude aldehyde liquid after decolorization in the decolorization tank is sent to the neutralization tank through the intermediate buffer tank, mixed with the alkali solution in the neutralization tank, and then sent to the dehydration tower; the top steam of the dehydration tower is condensed by the top cooler, and part of it is refluxed and part of it is sent back to the buffer tank, and the bottom liquid of the dehydration tower is reboiled in the kettle reboiler, and part of it is refluxed and part of it is sent to the distillation tower; the top steam of the distillation tower is condensed by the top cooler to obtain the special furfural, which is sent to the refined aldehyde storage tank, and the bottom liquid of the distillation tower is reboiled in the kettle reboiler, and part of it is refluxed and part of it is sent back to the deweight removal tower for further distillation.

4. The method for producing premium furfural according to claim 3, wherein: In step (1), the plant fiber material is at least one of corn cobs, rice husks, wood waste and wheat straw; the particle size of the plant fiber material particles is 10-30 mm; the mass fraction of the dilute sulfuric acid solution is 3%-8%, and the amount used is 40%-60% of the mass of the plant fiber material particles.

5. The method for producing premium furfural according to claim 3, characterized in that: In step (2), the hydrolysis kettles are connected in parallel in two or more groups, and each group is composed of two or more hydrolysis kettles connected in series; during the hydrolysis reaction, steam is introduced into the hydrolysis kettle, the operating pressure is 0.35-0.9 MPa, the temperature is 130-230°C, and the time is 1-6 h.

6. The method for producing premium furfural according to claim 3, characterized in that: In step (2), the operating temperature of the top of the lightness removal tower is 60-75°C, the operating temperature of the bottom of the tower is 80-100°C, and the operating pressure is 0.1-0.2 MPa.

7. The method for producing premium furfural according to claim 3, characterized in that: In step (2), the bottom of the deweighting tower is indirectly heated by steam, the operating temperature of the top of the tower is 80-105°C, the operating temperature of the bottom of the tower is 95-110°C, the operating pressure is 0.1-0.2 MPa, and the mixed liquid at the top of the tower is condensed to below 56°C through a top cooler; the material used for the adsorption decolorization is activated carbon or resin.

8. The method for producing premium furfural according to claim 3, characterized in that: In step (3), the intermediate buffer tank is filled with nitrogen to seal the decolorized crude aldehyde liquid; the refined aldehyde storage tank is filled with nitrogen to seal the premium furfural; the alkali solution is at least one of Na2CO3 solution, CaO solution, NaOH solution and NaHCO3 solution, with a mass fraction of 10% to 15%, and the amount used is 3% to 5% of the mass of the crude aldehyde liquid.

9. The method for producing premium furfural according to claim 3, characterized in that: In step (3), the dehydration tower adopts the operation of increasing temperature and decreasing pressure, an air valve is arranged at the bottom of the tower, and the air valve is opened during operation for air stirring, and the temperature at the top of the tower is controlled to rise to 80-105°C, the temperature at the bottom of the tower is 90-120°C, and the operating pressure is 0.1-0.2 MPa. When the temperature and vacuum degree are stable, the distillation is continued for 10-20 minutes.

10. The method for producing premium furfural according to claim 3, characterized in that: In step (3), the distillation tower adopts a double-filled tower in parallel for refining, the filler is BH type high-efficiency filler, the method is vacuum distillation or steam distillation, the operating temperature of the tower top is 50~100℃, the operating temperature of the tower bottom is 90~115℃, the operating pressure is 0.1~0.2 MPa, the formaldehyde sludge is discharged once every 3 refining kettles, and the tower is washed once every 4 refining kettles.

Images