Continuous production of furfural

Abstract

This invention relates to the field of furfural preparation technology, and discloses a continuous furfural production apparatus and method. The continuous furfural production apparatus includes: multiple feeding hoppers, each with a discharge port at its bottom; a hydrolysis reactor located below the feeding hoppers, with a second inlet at its top and a first slag discharge port at its bottom; all discharge ports connected to the second inlet via discharge pipelines; multiple discharge hoppers, each with a slag inlet at its top, and the first slag discharge port connected to all slag inlets via slag discharge pipelines; and a discharge control system for controlling the discharge and slag discharge speeds. The disclosed production method, implemented using this apparatus, controls the bulk density of the material in the hydrolysis reactor to be 200~450 kg / m³. 3 The apparatus and method provided by this invention enable continuous production of furfural, improving its yield and productivity.

Description

Technical Field

[0001] This invention relates to the field of furfural preparation technology, and more specifically, to a continuous furfural production apparatus and method. Background Technology

[0002] With fossil fuel resources dwindling, finding a new, renewable, and environmentally friendly alternative energy source is crucial. The utilization of biomass not only develops a new energy platform and reduces CO2 emissions, but also increases the ways to utilize waste resources and can significantly support agricultural economic development.

[0003] Furfural is an important chemical produced from biomass, and it is widely used in resin synthesis, fuel additives, pharmaceuticals, and pesticide intermediates. Currently, the industrial production of bio-based furfural mainly relies on agricultural and forestry waste (such as corn cobs, bagasse, and corn stalks) as raw materials. Xylose is produced by acid-catalyzed hydrolysis of hemicellulose in the raw materials, and then the xylose is further dehydrated and cyclized to produce furfural.

[0004] From the perspective of furfural production principles, it mainly involves two steps: hydrolysis and dehydration. Based on whether these two steps occur in the same reactor, furfural production methods are categorized into one-step and two-step methods. The one-step method, due to its lower equipment investment and simpler operation, is widely used in the furfural industry. Currently, the mainstream furfural production process is the batch one-step method. The main operation involves adding acid-mixed biomass to a reactor, introducing steam, and reacting for a period of time to obtain furfural product. After the reaction is complete, the remaining furfural residue is discharged, and new raw materials are added to repeat the above steps.

[0005] However, existing one-step production processes suffer from low furfural yield, cumbersome batch operation, and low single-reactor capacity. Taking an existing batch reactor as an example, a single reactor requires approximately 11 tons of biomass to produce 1 ton of furfural, yielding about 45% of the theoretical yield. The single-reactor operation time is 4 hours, with 3 hours for reaction and 1 hour for loading, unloading, and heating / pressurization. Furthermore, due to the reduced volume of biomass after the reaction, the effective utilization rate of the single-reactor volume is only 60%. To overcome the shortcomings of batch operation, continuous processes have been explored. CN115536620A provides a method for the continuous production of furfural and 5-hydroxymethylfurfural from cellulosic biomass, using a screw conveyor for continuous biomass feeding and relying on the screw to compact the biomass and overcome the pressure difference between the inside and outside of the reactor. CN101343292B provides a method for the continuous hydrolysis of cellulosic biomass, using a variable-pitch screw pusher for continuous biomass feeding and a constant-pitch vertical screw pusher as the hydrolysis reactor to move the biomass. Conventional screw conveyors lack compression and sealing capabilities. Without a seal, they cannot overcome pressure differentials, leading to backflow of biomass during feeding due to high internal pressure. Conversely, variable pitch screws are used to seal the reactor, which further compacts the biomass. Therefore, reported continuous processes tend to compress biomass, reducing contact with steam, resulting in incomplete reactions and reactor blockage. Alternatively, reactors are typically open and cannot be sealed, easily causing product loss and material backflow. Furthermore, screw-type mechanical conveyors are not easily scaled up for production.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a continuous furfural production apparatus and method, suitable for high-yield continuous production, and aimed at improving furfural yield.

[0008] This invention is implemented as follows: In a first aspect, the present invention provides a continuous furfural production apparatus, comprising: Multiple feeding bins, each feeding bin having a first feeding port at the top and a discharging port at the bottom; A hydrolysis reactor is located below the plurality of feeding hoppers. The hydrolysis reactor is provided with a high-temperature steam inlet at the bottom, a second feed inlet and a product outlet at the top, and a first slag discharge outlet at the bottom. All the discharge outlets are connected to the second feed inlet via a discharge pipeline. Multiple feeding hoppers, each feeding hopper having a slag inlet at the top and a second slag outlet at the bottom; the first slag outlet and all the slag inlets are connected by a slag discharge pipeline; The feeding control system is used to control the opening and closing of the pipeline between each of the feeding ports and the second feed port, and the feeding rate of the feed hopper when the pipeline is open; it is also used to control the opening and closing of the pipeline between each of the slag inlets and the first slag outlets, and the slag discharge rate of the hydrolysis reactor when the pipeline is open.

[0009] In optional embodiments, at least one of the following technical features (1) to (3) is also included: (1) The feeding control system also includes a feeder and a slag discharger; The feeder is installed on the feed pipeline and is used to control the feed rate of each feed hopper; (2) The feeding control system further includes a slag discharger, which is connected to the first slag discharge port and is used to control the slag discharge rate of the hydrolysis reactor. (3) The feeding control system includes multiple feeding valves. At least one feeding valve is provided on the pipeline connecting each feeding port and the second feeding port. The opening and closing of the corresponding pipeline is achieved by adjusting the feeding valve.

[0010] In optional embodiments, at least one of the following technical features (1) to (6) is also included: (1) Each feeding hopper is equipped with an auxiliary feeding device at the bottom for assisting feeding.

[0011] (2) A feed stabilizer is installed at the bottom of the hydrolysis reactor to help biomass feed smoothly. The feed stabilizer adopts one or more of the following types: mechanical, pneumatic, vibration, and chemical. The feed stabilizer is preferably pneumatic. The equipment model is KQP-B-100 and the gas source is nitrogen.

[0012] (3) Each feeding hopper is equipped with an exhaust vent at the top; (4) Each feeding hopper is also equipped with a first high-pressure carrier gas inlet; (5) The bottom of each feeding hopper, the bottom of the hydrolysis reactor and / or the bottom of each discharging hopper is conical with a cone angle of 30~75°; (6) Each feeding bin is equipped with a second high-pressure carrier gas inlet.

[0013] In an optional embodiment, a furfural vapor delivery pipeline is connected to the product discharge outlet. The furfural vapor delivery pipeline includes a main line and multiple branch lines connected in parallel to the main line. A filter screen with a pore size of 20 to 60 mesh is provided on the main line, and a filter with a pore size of 80 to 120 mesh is provided on each of the branch lines. Optionally, a first pressure sensor and a second pressure sensor are respectively installed before and after each filter on the furfural vapor delivery pipeline. Optionally, on each branch line, a shut-off valve one is provided at the front end of the filter and a shut-off valve two is provided at the rear end, a purge steam branch is provided between the filter and the shut-off valve one, and a vent branch is provided between the filter and the shut-off valve two.

[0014] In an optional embodiment, the feeding control system includes a plurality of slag discharge valves, and at least one of the slag discharge valves is provided on the pipeline connecting each slag inlet and the first slag outlet. The pipeline is opened or closed by controlling the opening and closing of the slag discharge valves. Optionally, each of the second slag discharge ports is connected to a slag discharge pipe, and the slag discharge pipe is equipped with a slag discharge valve.

[0015] In an optional embodiment, the furfural continuous production apparatus further includes a biomass acid mixing device, with a feed pipe connected to each first feed inlet, and the discharge outlet of the biomass acid mixing device connected to each feed pipe via a conveying mechanism. Optionally, the conveying mechanism is a tubular chain conveyor.

[0016] In a second aspect, the present invention provides a continuous furfural production method, implemented using a continuous furfural production apparatus as described in any of the foregoing embodiments, comprising: Multiple feeding hoppers are alternately and continuously feeding materials into the hydrolysis reactor. The materials entering the hydrolysis reactor from the feeding hoppers are biomass raw materials that have been mixed with acid. While feeding the biomass raw material into the hydrolysis reactor from the feeding hopper, high-temperature steam is introduced into the high-temperature steam inlet, so that the acid-mixed biomass raw material reacts with the high-temperature steam in the hydrolysis reactor to generate furfural steam. The generated furfural steam is discharged from the product outlet, and the generated residue is discharged into multiple feeding hoppers that are used alternately.

[0017] Since the continuous production apparatus provided in this embodiment of the invention is implemented, it can achieve continuous production of furfural while effectively avoiding incomplete reaction or material blockage, and can significantly improve production capacity compared with the intermittent process of hydrolysis reactor of the same size.

[0018] In a preferred embodiment, during the reaction process, the bulk density ρ of the material inside the hydrolysis reactor is controlled to be 200~450 kg / m³. 3 This ensures that the biomass feedstock after acid mixing is in full contact with the high-temperature steam, resulting in a complete reaction and a high yield.

[0019] Specifically, the main methods for controlling the loose density ρ include controlling the matching of the feed rate and the discharge rate to ensure that the loose density of the material in the hydrolysis reactor meets the requirements.

[0020] In a preferred embodiment, ρ is controlled to be 200~450 kg / m³ by the following formula (1). 3 : Equation (1): ; In equation (1), ρ 进 ρ is the density of the material entering the hydrolysis reactor. 出 To determine the density of the slag from the hydrolysis reactor, v 进 v is the velocity of the material entering the hydrolysis reactor. 出 The rate at which material is discharged from the hydrolysis reactor is given by t, where t is the production run time; M0 is the initial mass of material in the hydrolysis reactor; h is the height of the material in the hydrolysis reactor; and A is the mass of material in the reactor. 平均 This represents the average cross-sectional area of ​​the hydrolysis reactor.

[0021] Optionally, v 进 2~12 m 3 / h,v 出 2~12 m 3 / h, V is 11~24 m 3 ;ρ 进 200~300 kg / m 3 , ρ 出 220~350 kg / m 3 M0 is 2000~5000 kg; In an optional implementation, τ is controlled to be 2~5h by the following formula (2): Equation (2): ; In the formula, v 进 v is the feed rate of the hydrolysis reactor. 出 V represents the slag discharge rate of the hydrolysis reactor, and V is the effective volume of the hydrolysis reactor.

[0022] As shown in equation (2) above, it is preferable to control τ within 2~5h to balance the yield. The inventors have found that if the value of τ is too large or too small, it will affect the product yield.

[0023] Optionally, the reaction temperature inside the hydrolysis reactor is 170~190℃, and the reaction pressure is 0.7~1.2MPa; Optionally, the temperature of the high-temperature steam introduced into the hydrolysis reactor is 180–200°C. Optionally, before feeding material from the feed hopper into the hydrolysis reactor, inert gas is introduced into the feed hopper to make the pressure in the feed hopper 0.01 to 0.1 MPaG higher than the pressure inside the hydrolysis reactor, and then feeding begins. Optionally, before switching the feed hopper to be connected to the hydrolysis reactor, inert gas is introduced into it to make the pressure in the feed hopper 0.01~0.1 MPaG lower than the pressure inside the hydrolysis reactor.

[0024] In an optional embodiment, the biomass feedstock after acidification is obtained by uniformly mixing the acid, which serves as a catalyst, with the biomass feedstock. The acid is selected from at least one of sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, and acetic acid; Optionally, the acid is mixed with the biomass feedstock in the form of an acid solution, the mass concentration of the acid solution is 2~10wt%, and the biomass feedstock and acid solution are mixed at a mass ratio of 1~5:1.

[0025] Optionally, the particle size of the biomass feedstock is 6–50 mm.

[0026] In an optional embodiment, the biomass feedstock includes at least one of wood materials and non-wood lignocellulose. Optionally, the wood species used in the wood material are at least one of broadleaf wood, coniferous wood, and grass; Alternatively, the wood material may be sourced from the leaves; Optionally, the non-timber lignocellulose is selected from bast fibers, seed fibers, or agricultural and forestry waste; alternatively, the non-timber lignocellulose is selected from at least one of corn cobs, corn stalks, sugarcane bagasse, wheat straw, cotton stalks, cottonseed hulls, and peanut shells.

[0027] The present invention has the following beneficial effects: The furfural continuous production apparatus provided by this invention features multiple feeding hoppers above the hydrolysis reactor. Before the reactants are introduced into the reactor, they are temporarily stored in these hoppers. Continuous feeding is achieved by alternately feeding the reactor from these hoppers. This continuous feeding method, compared to screw conveyors, avoids material compression and prevents incomplete reaction or blockage. A feeding control system is also included to regulate the operating status and feeding rate of the feeding hoppers. The slag is discharged into a sealable feeding hopper, effectively controlling the pressure of the entire reaction equipment and ensuring smooth feeding and slag discharge. This, in turn, ensures the material in the hydrolysis reactor has a suitable bulk density. The alternating use of multiple feeding hoppers allows for continuous slag discharge while maintaining stable system pressure. The furfural continuous production apparatus provided by this invention achieves continuous furfural production while effectively avoiding incomplete reaction or blockage, significantly increasing production capacity compared to intermittent processes using hydrolysis reactors of the same size.

[0028] The continuous furfural production method provided by this invention, implemented through the continuous production apparatus provided in the embodiments of this invention, can achieve continuous furfural production while effectively avoiding incomplete reaction or material blockage. Compared with the intermittent process of hydrolysis reactor of the same size, it can significantly improve the production capacity. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the continuous furfural production apparatus provided in Embodiment 1 of the present invention; Figure 2 for Figure 1 A schematic diagram of the structure of the furfural steam transmission pipeline.

[0031] Icon: 100-Furfural Continuous Production Unit; 110 - Biomass acid mixing equipment; 111 - Biomass inlet; 112 - Catalyst spray head; 113 - Screw auger; 120-Tube Chain Conveyor; 130 - Feeding bin; 131 - Feed pipe; 131a - Feeding valve; 132 - First high-pressure carrier gas conveying pipe; 133 - Tail gas exhaust pipe; 134 - Auxiliary feeding equipment; 140 - Feeding pipeline; 141 - Feeding valve; 142 - Feeder; 150 - Hydrolysis reactor; 151 - High-temperature steam conveying pipe; 152 - Feed stabilizer; 153 - Slag discharger; 160 - Furfural steam delivery pipeline; 161 - Main line; 161a - Filter screen; 162 - Branch line; 162a - Filter; 163 - First pressure sensor; 164 - Second pressure sensor; 165 - Shut-off valve one; 166 - Shut-off valve two; 167 - Purge steam branch; 168 - Vent branch; 170 - Feeding bin; 171 - Second high-pressure carrier gas conveying pipe; 172 - Slag discharge pipe; 172a - Slag discharge valve; 180 - Slag discharge pipeline; 181 - Slag discharge valve. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0034] like Figure 1As shown, an embodiment of the present invention provides a furfural continuous production apparatus 100, comprising: Multiple feeding hoppers 130, each feeding hopper 130 is provided with a first feeding port at the top and a discharging port at the bottom; The hydrolysis reactor 150 is located below multiple feeding hoppers 130. The lower part of the hydrolysis reactor 150 is provided with a high-temperature steam inlet, the upper part is provided with a second feed inlet and a product discharge outlet, and the bottom is provided with a first slag discharge outlet. All the discharge outlets are connected to the second feed inlet through a discharge pipeline 140. Multiple feeding hoppers 170, each feeding hopper 170 is provided with a slag inlet at the top and a second slag outlet at the bottom; the first slag outlet and all slag inlets are connected by a slag discharge pipeline 180; The feeding control system controls the opening and closing of pipelines between each feeding port and the second feeding port, as well as the feeding rate of the corresponding feeding hopper 130 when the circuit is open; it also controls the opening and closing of pipelines between each slag inlet and the first slag outlet, as well as the slag feeding rate of the corresponding hydrolysis reactor 150 when the circuit is open. The feeding control system uses conventional technology (e.g., PLC), and obviously includes a controller. The controller signals are connected to the drive mechanisms of each controlled device. The controller is configured to issue control commands to the corresponding drive mechanisms according to a preset program or an input program to drive the operation of specific controlled devices. The furfural continuous production apparatus 100 provided in this embodiment of the invention utilizes multiple feeding hoppers 130 above a hydrolysis reactor 150. Before the reactants are introduced into the hydrolysis reactor 150, they are temporarily stored in these hoppers. Continuous feeding is achieved by alternately feeding materials from these hoppers 130 into the hydrolysis reactor 150. This continuous feeding method, compared to screw conveying, does not compress the materials, thus avoiding incomplete reaction or material blockage. A feeding control system is also included to control the operating status and feeding rate of the feeding hoppers 170. The slag is discharged into the sealable feeding hoppers 170, effectively controlling the pressure of the entire reaction equipment and ensuring smooth material and slag discharge. This, in turn, ensures that the material in the hydrolysis reactor 150 has a suitable bulk density. The alternating use of multiple feeding hoppers 170 allows for continuous slag discharge while maintaining stable system pressure. The furfural continuous production apparatus 100 provided in this embodiment of the invention can achieve continuous production of furfural while effectively avoiding incomplete reaction or material blockage. Compared with the intermittent process of the hydrolysis reactor 150 of the same size, it can significantly improve the production capacity.

[0035] Optionally, the furfural continuous production apparatus 100 also includes a biomass acid mixing device 110, with a feed pipe 131 connected to each first feed inlet, and the discharge outlet of the biomass acid mixing device 110 connected to each feed pipe 131 via a conveying mechanism.

[0036] Specifically, the biomass acid mixing equipment 110 is equipped with a catalyst spray head 112 and a biomass inlet 111 at the top, and an auger 113 in the middle. After the biomass raw material is crushed to a size of 6-50mm by a crusher, it is added to the acid mixing equipment through the biomass inlet 111. Acid is sprayed into the equipment from the top through the catalyst spray head 112, and the auger 113 is used to agitate the biomass for acid mixing. The mixed material is then conveyed to the feed pipe 131 via a conveying mechanism, and then enters the feeding hopper 130. This conveying mechanism is, for example, a tubular chain conveyor 120. The tubular chain conveyor 120 prevents acid vapor and biomass dust from leaking out.

[0037] Optionally, each feed pipe 131 is equipped with a feeding valve 131a, which stops feeding into the feeding hopper 130 and achieves overall sealing of the furfural continuous production device 100 by closing the feeding valve 131a.

[0038] Optionally, each feeding hopper 130 has the following specific structure: a first feed inlet, a tail gas vent, and a first high-pressure carrier gas inlet are provided at the top, and a discharge outlet is provided at the bottom. A tail gas vent pipe 133 is connected to the tail gas vent, and a first high-pressure carrier gas delivery pipe 132 is connected to the first high-pressure carrier gas inlet.

[0039] Before feeding into the feeding hopper 130, it is preferable to introduce high-pressure inert gas (e.g., nitrogen) into it through the first high-pressure carrier gas conveying pipe 132 to balance the pressure in the feeding hopper and the hydrolysis reactor. When the pressure in the feeding hopper 130 rises to slightly higher than the pressure in the reactor, the valve is closed to stop the introduction of high-pressure inert gas. Then, feeding begins, relying on high-pressure impact and gravity to achieve feeding, so as to better prevent biomass from bridging and blocking in the feeding hopper 130 and hindering feeding.

[0040] After the material in a feeding hopper 130 is emptied, the exhaust gas is discharged and depressurized through the exhaust gas vent pipe 133 before new material is added.

[0041] In existing technologies, biomass feedstocks are typically transferred directly from ambient temperature and pressure to high temperature and pressure, which can easily lead to steam leakage or difficulties in feeding. In this solution, a feeding hopper 130 is installed before the hydrolysis reactor 150, and the feeding hopper 130 is kept under high pressure. The feeding hopper 130 acts as a buffer zone, which allows the biomass feedstock to be fed more smoothly and avoids material backflow, steam leakage, or furfural vapor escaping from the reactor into the feeding hopper, which would increase the reaction time, generate side reactions, and thus reduce the yield.

[0042] Optionally, each feeding hopper 130 is provided with an auxiliary unloading device 134 at its bottom.

[0043] Auxiliary feeding equipment 134, such as scraper feeders, with scrapers of type F, T, L, J, U or V, etc., and scraper feeder diameter of 200~500mm.

[0044] Optionally, the auxiliary feeding device 134 adopts a scraper F300, where F = F-type scraper and 300 = feeder diameter is 300mm.

[0045] An auxiliary feeding device 134 is installed to keep the bottom of the feeding hopper 130 in a loose state, so as to better avoid the problem of obstructed feeding.

[0046] Optionally, the feeding control system includes multiple feeding valves 141, and at least one feeding valve 141 is provided on the pipeline connecting each feeding port and the second feeding port. The opening and closing of the corresponding pipeline can be achieved by adjusting the feeding valve 141.

[0047] Optionally, the feeding control system also includes a feeder 142; the feeder 142 is disposed on the feeding pipeline 140 and is used to control the feeding rate of each feeding bin 130.

[0048] The function of the feeder 142 is to control the material conveying rate. Rotary valves are commonly used to control this rate. A rotary valve is a conventional device for conveying and quantitatively feeding bulk materials; for example, a star-shaped feeder valve, where the impeller is star-shaped and its speed is adjusted by a variable frequency motor, thus directly controlling the feeding amount per unit time. Furthermore, the feeder 142 uses an XF300RSQ star-shaped feeder valve with the following parameters: XF = star-shaped feeder valve, 300 = nominal diameter 300mm, R = heat-resistant type, S = servo drive, Q = quantitative feeding.

[0049] Optionally, the feeder 142 may not be installed. By installing a weighing sensor in the feeding hopper, controlling the opening of the feeding valve 141, and simultaneously monitoring the reduction of the material weight in the feeding hopper, the material conveying rate can also be controlled.

[0050] Optionally, the specific structure of the hydrolysis reactor 150 is as follows: A product outlet is provided at the top of the hydrolysis reactor 150, and a furfural vapor delivery pipeline 160 is connected to the product outlet. The furfural vapor delivery pipeline 160 is used to transport the generated furfural vapor to the downstream end for purification. The furfural vapor delivery pipeline 160 includes a main line 161 and multiple parallel branch lines 162 connected to the main line 161. A filter screen 161a is provided on the main line 161, and a filter 162a and a valve for adjusting the opening and closing of the pipeline section or the product flow rate are provided on each branch line 162. The filter screen 161a filters the large-diameter biomass particles blown up, and its mesh size is relatively large (the filter pore size is 20~60 mesh, specifically, for example, 20 mesh, 30 mesh, 40 mesh or 60 mesh). The filter screen 162a filters the small-diameter biomass particles blown up, and its mesh size is relatively small (the filter pore size is 80~120 mesh, specifically, for example, 80 mesh, 100 mesh or 120 mesh).

[0051] Furthermore, a first pressure sensor 163 and a second pressure sensor 164 are installed before and after the filter 162a, respectively. When the pressure difference ΔP = P reflected by the first pressure sensor 163 and the second pressure sensor 164 is detected... 前 -P 后 When the threshold is reached, it indicates severe coking, and the pipeline needs to be switched.

[0052] Furthermore, on each branch line 162, a first shut-off valve 165 is provided at the front end of the filter 162a and a second shut-off valve 166 is provided at the rear end. A purge steam branch line 167 is provided between the filter 162a and the first shut-off valve 165, and a vent branch line 168 is provided between the filter 162a and the second shut-off valve 166.

[0053] Filter screen 161a and filter 162a need to be cleaned regularly, otherwise severe blockage will prevent the equipment from operating normally. When cleaning filter 162a, close the first shut-off valve 165 and the second shut-off valve 166 to completely close the front and rear pipelines. Then, purge steam is introduced through the purge steam branch 167 to clean filter 162a. After cleaning, the steam carrying the filter residue is discharged from the vent branch 168. When filter screen 161a needs to be cleaned, open the first shut-off valve 165 and introduce purge steam through the purge steam branch 167 to clean filter screen 161a in the reverse direction of the bus 161. The steam carrying the filter residue enters the hydrolysis reactor 150 and is discharged through the slag discharger 153 and other structures.

[0054] A high-temperature steam inlet is provided at the lower part of the hydrolysis reactor 150. A high-temperature steam delivery pipe 151 is connected to the high-temperature steam inlet. A steam valve is provided on the steam delivery pipe. The steam valve is used to control the opening and closing of the steam delivery pipe or the steam flow rate.

[0055] Optionally, a feed stabilizer 152 is installed at the bottom of the hydrolysis reactor 150. This effectively prevents biomass feedstock from bridging and clogging within the hydrolysis reactor 150, improving production efficiency. The specific type of feed stabilizer 152 is not limited; it can be one or a combination of mechanical, pneumatic, vibratory, or chemical types. A pneumatic type is preferred. The optional feed stabilizer 152 is model KQP-B-100L, with nitrogen as the gas source.

[0056] Optionally, the feeding control system also includes a slag discharger 153; the slag discharger 153 is connected to the first slag discharge port and is used to control the slag discharge rate of the hydrolysis reactor 150.

[0057] The coordinated arrangement of the feeder 142 and the slag discharger 153 makes it easy to control the feeding speed and the slag discharge speed, thereby maintaining the amount of material in the hydrolysis reactor 150 within a suitable range, thus better ensuring the reaction is complete and having better production efficiency.

[0058] The feed stabilizer 152 works in conjunction with the slag discharger 153 to prevent unpredictable blockages that could disrupt slag discharge. It can be activated via a timer or automatically when the slag flow rate decreases. For example, a timer can be set to activate every 5 to 20 minutes, with each activation cycle lasting in milliseconds (ms) to ensure impact force, such as 50 to 200 ms. Specifically, the feed stabilizer 152 can be of any type; for example, a KQP-B-100L can be used, with nitrogen as the gas source.

[0059] The slag discharger 153 and the feeder 142 work together to control the slag discharge rate and the feed rate, so that the material in the hydrolysis reactor 150 is kept within a suitable range, thereby ensuring production quality and efficiency.

[0060] Optionally, the slag discharger 153 functions the same as the feeder 142. The specific type of slag discharger 153 is not limited; specifically, the slag discharger 153 can use a star-shaped feeder valve XF300RSQ with the following parameters: XF = star-shaped feeder valve, 300 = nominal diameter 300mm, R = heat-resistant type, S = servo drive, Q = quantitative type.

[0061] Optionally, the material feeding control system includes multiple slag discharge valves 181, and at least one slag discharge valve 181 is provided on the pipeline connecting each slag inlet and the first slag outlet. The opening and closing of the pipeline is achieved by controlling the opening and closing of the slag discharge valve 181.

[0062] Optionally, in addition to the slag inlet and the second slag outlet, each discharge hopper 170 is also provided with a second high-pressure carrier gas inlet, which is connected to a second high-pressure carrier gas delivery pipe 171. Inert gas (such as nitrogen) is introduced into the discharge hopper 170 through the second high-pressure carrier gas delivery pipe 171, similar to the introduction of inert gas into the upper hopper 130. The introduction of high-pressure gas into the discharge hopper 170 is used to provide a buffer transition and balance the pressure within the entire equipment.

[0063] Both the feeding hopper 130 and the discharging hopper 170 are filled with gas during operation to keep them under high pressure, which can effectively buffer the feeding and slag discharge of the hydrolysis reactor 150, better overcome the pressure difference during the feeding and discharging process, and better keep the material inside the hydrolysis reactor 150 in a conveying state, thereby ensuring a higher yield in the production process.

[0064] Furthermore, each second slag discharge port is connected to a slag discharge pipe 172, and a slag discharge valve 172a is installed on the slag discharge pipe 172. When a slag material in a feeding hopper 170 is full, the corresponding slag discharge valve 181 is closed and the corresponding slag discharge valve 172a is opened to discharge the slag material.

[0065] Furthermore, each feeding hopper 170 is equipped with a tuning fork level gauge. When the material level in feeding hopper 170 reaches 90%, the feeding tank is switched. The original feeding tank opens the slag discharge valve 172a, and relies on the internal residual pressure to discharge the furfural residue material onto the conveyor belt, which is then sent to the thermal power system for incineration to produce steam.

[0066] Optionally, to achieve smoother material discharge, the bottoms of the feeding hopper 130, the hydrolysis reactor 150, and / or the discharging hopper 170 are conical, with a cone angle of 30~75° (e.g., 30°, 45°, 60°, or 75°). Preferably, the cone angle of the feeding hopper 130, the hydrolysis reactor 150, and / or the discharging hopper 170 is 60°. Different biomass materials have different preferred angles of repose, and the cone angle can be set accordingly based on the preferred angle of repose required by the biomass material.

[0067] The continuous furfural production method provided in this embodiment of the invention is implemented using the continuous furfural production apparatus 100 provided in this embodiment of the invention, and includes: Multiple feeding hoppers 130 alternately feed materials into the hydrolysis reactor 150. The material entering the hydrolysis reactor 150 from the feeding hoppers 130 is the biomass raw material after acid mixing. While feeding material from the feeding hopper 130 into the hydrolysis reactor 150, high-temperature steam is introduced into the high-temperature steam inlet, so that the acid-mixed biomass raw material reacts with the high-temperature steam in the hydrolysis reactor 150 to generate furfural steam. The generated furfural steam is discharged from the product outlet, and the generated slag is discharged into multiple feeding hoppers 170 that are used alternately.

[0068] The continuous furfural production method provided by this invention, implemented through the continuous production apparatus provided in the embodiments of this invention, can achieve continuous furfural production while effectively avoiding incomplete reaction or material blockage. Compared with the intermittent process of the same size hydrolysis reactor 150, it can significantly improve the production capacity.

[0069] During the reaction, the bulk density ρ of the material inside the hydrolysis reactor 150 is controlled to be 200~450 kg / m³. 3 This ensures that the biomass feedstock, after being acidified, is in full contact with the high-temperature steam, resulting in a complete reaction and a high yield. If the loose density is too high (>450 kg / m³),... 3 If the material is piled too tightly, the contact between it and the steam will be uneven, leading to incomplete reaction and reduced yield. It will also prevent the generated furfural vapor from dissipating properly, increasing side reactions. If the loose density is too low (<200 kg / m³), the reaction will be unsuccessful. 3 Production efficiency will decrease, and when the bulk density is too low, the amount of high-pressure steam used will be large, and excessive steam will also lead to increased energy consumption.

[0070] Preferably, ρ is controlled to be 200~450 kg / m³ by the following formula (1). 3 (e.g., 200 kg / m) 3 250 kg / m 3 300kg / m 3 350 kg / m 3 400 kg / m 3 Or 450 kg / m 3 ): Equation (1):

[0071] In equation (1), ρ 进 ρ is the density of the material entering the hydrolysis reactor. 出 To determine the density of the slag from the hydrolysis reactor, v 进 v is the velocity of the material entering the hydrolysis reactor. 出 The rate at which material is discharged from the hydrolysis reactor is given by t, where t is the production run time; M0 is the initial mass of material in the hydrolysis reactor; h is the height of the material in the hydrolysis reactor; and A is the mass of material in the reactor. 平均 This represents the average cross-sectional area of ​​the hydrolysis reactor.

[0072] A 平均The calculation method is based on the actual situation of the reactor and can be performed using a discretization method. m points are set along the height direction of the reactor, with heights of h1, h2, ..., hm respectively. The cross-sectional areas corresponding to h1, h2, ..., hm along the height direction of the reactor are measured as A1, A2, ..., Am, and then averaged. Generally, the reactor is regular in shape. For example, in this invention, a moving bed reactor is used, with a cylindrical outer shape, an inner diameter of 1.5~3m, and a height of 5~20m. In this case, A... 平均 It is the area of ​​any cross section along the height direction of the reactor, for example, in the embodiment of this application, A=2m. 2 The reaction vessel.

[0073] Furthermore, to ensure better yields, some embodiments use operating parameters such as: v 进 2~12 m 3 / h,v 出 2~12 m 3 / h;ρ 进 200~300 kg / m 3 , ρ 出 220~350 kg / m 3 , where v 进 and v 出 Adjusted by the feeding control system, ρ 进 and ρ 出 The mass of the material in the hydrolysis reactor was determined by testing; M0 is the initial mass of the material in the hydrolysis reactor, and h is the height of the material in the hydrolysis reactor.

[0074] Optionally, v 进 and v 出 2 m respectively 3 / h、3 m 3 / h、4 m 3 / h、5 m 3 / h、6 m 3 / h、7 m 3 / h、8 m 3 / h、9m 3 / h, 10 m 3 / h、11 m 3 / h or 12 m 3 / h, or any other value within the range of any two of the aforementioned values.

[0075] Optionally, ρ 进 200 kg / m 3 230 kg / m 3 250 kg / m 3 280 kg / m 3 Or 300 kg / m3 , or any other value within the range of any two of the aforementioned values.

[0076] Optionally, ρ 出 220 kg / m 3 250 kg / m 3 280 kg / m 3 300 kg / m 3 Or 350 kg / m 3 , or any other value within the range of any two of the aforementioned values.

[0077] Optionally, the initial material mass M0 in the hydrolysis reactor is 2000~5000 kg (e.g., 2000 kg, 3000 kg, 4000 kg or 5000 kg, or other values ​​within any two of the aforementioned values).

[0078] In actual production, after selecting the reactor and biomass feedstock, the initial reactor loading M0 is a constant value, and the reactor's A... 平均 The height h of the material in the reactor remains essentially constant. Specifically, it is adjusted by the flow rate of high-temperature steam; a larger flow rate results in a larger h, and a smaller flow rate results in a smaller h. In this invention, A... 平均 *h can also be expressed as the effective volume V of the reactor; v 进 and v 出 The control is achieved through a feeder and a slag discharger, respectively; under steady-state operation, ρ can be considered... 进 and ρ 出 This is a constant value. When the data in equation (1) is set as described above, equation (1) can be expressed as follows: or ; As shown above, once the system reaches steady state, ρ will continuously increase with increasing running time. The inventors discovered that when ρ increases to 450 kg / m³... 3 Continuing to increase the yield significantly impacts the product yield. To address this issue, when ρ increases to 450 kg / m³... 3 Then, add v 出 Until ρ reaches 200 kg / m 3 Add v 出 .

[0079] Optionally, M0 is 2000~5000 kg, h is 8~15 m, and A 平均 2~15m 2Specifically, M0 is, for example, 2000kg, 3000kg, 4000kg, or 5000kg, or other values ​​within the range of any two of the aforementioned values; h is, for example, 8m, 10m, 12m, or 15m, or other values ​​within the range of any two of the aforementioned values; A 平均 For example, 2m 2 5m 2 8m 2 10m 2 or 15m 2 , or any other value within the range of any two of the aforementioned values.

[0080] Alternatively, control can be performed using the following methods to maintain v 进 Keep the initial ρ constant at 200~250 kg / m 3 As the operating time increases, ρ will increase; when it increases to 300~450 kg / m 3 Adjust v 出 This brings ρ back to 200~250 kg / m 3 The interval is repeated. If v is maintained... 出 Remain unchanged, by adjusting v 进 It can also keep ρ within the required range.

[0081] Optionally, τ can be controlled to be 2~5h (e.g., 2 h, 3 h, 4 h or 5 h, or other values ​​within the range of any two of the aforementioned values) by the following formula (2): Equation (2): ; In the formula, v 进 v is the feed rate of the hydrolysis reactor. 出 V represents the slag discharge rate of the hydrolysis reactor, and V is the effective volume of the hydrolysis reactor. Once the reactor is determined, V is a fixed value. In this invention, the preferred reactor volume V is 11~24 m³. 3 (e.g., 11 m) 3 15m 3 20 m 3 or 24 m 3 ).

[0082] As shown in equation (2) above, it is preferable to control τ within 2~5h to balance the yield.

[0083] Optionally, to ensure a suitable reaction rate and to enable better continuous and stable operation of the equipment, the reaction temperature inside the hydrolysis reactor 150 is 170~190℃ (e.g., 170℃, 180℃ or 190℃, or other values ​​within the range of any two of the aforementioned values), and the reaction pressure is 0.7~1.2MPa (e.g., 0.7 MPa, 1 MPa or 1.2 MPa, or other values ​​within the range of any two of the aforementioned values).

[0084] Optionally, to ensure that the temperature inside the hydrolysis reactor 150 is within a suitable range, the temperature of the high-temperature steam introduced into the hydrolysis reactor 150 is 180~200℃ (e.g., 180℃, 190℃ or 200℃, or other values ​​within the range of any two of the aforementioned values).

[0085] Optionally, before feeding material from the feeding hopper 130 into the hydrolysis reactor 150, the pressure of the hopper 130 is made to be 0.01 to 0.1 MPaG higher than the pressure inside the hydrolysis reactor 150, and then feeding can begin. The pressure can be 0.01 MPaG, 0.02 MPaG, 0.05 MPaG, or 0.1 MPaG higher, or any other value within the range of any two of the aforementioned values.

[0086] Optionally, in order to balance the pressure difference during the slag discharge process in the reactor and ensure a more stable pressure inside the reactor, before the discharge hopper 170 is switched to be connected to the hydrolysis reactor 150, inert gas is introduced into it so that the pressure in the discharge hopper 170 is 0.01 to 0.1 MPaG lower than the pressure inside the hydrolysis reactor.

[0087] Specifically, the biomass feedstock after acid mixing is obtained by uniformly mixing the acid, which serves as a catalyst, with the biomass feedstock.

[0088] Furthermore, the acid includes, but is not limited to, at least one selected from sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, and acetic acid.

[0089] Furthermore, the acid is mixed with the biomass feedstock in the form of an acid solution, the mass concentration of which is 2 to 10 wt% (e.g., 2 wt%, 5 wt%, 8 wt% or 10 wt%), and the biomass feedstock and acid solution are mixed at a mass ratio of 1 to 5:1 (e.g., 1:1, 2:1, 3:1 or 5:1).

[0090] In the implementation of this invention, the selection of acid, the mass concentration of the acid solution, and the mass ratio of biomass raw material to acid solution can be chosen within a wide range. The above-listed ranges are preferred embodiments. It is understood that this invention is not limited thereto, and those skilled in the art can choose from outside the above ranges according to actual process requirements.

[0091] It should be noted that the reason for mixing the acid with the biomass feedstock in the form of an acidic liquid is that acidic liquid is easier to mix with the biomass feedstock. In some other embodiments of the present invention, the acid may also be mixed with the biomass feedstock in solid form.

[0092] Furthermore, the biomass raw materials used as reaction feedstocks include, but are not limited to, at least one of wood materials and non-wood lignocellulose. Optionally, the wood species include, but are not limited to, at least one of broadleaf trees, coniferous trees, and grasses. Optionally, the wood material is generally obtained from the leaves. Optionally, the non-wood lignocellulose includes, but is not limited to, materials selected from bast fibers, seed fibers, or agricultural and forestry waste. Optionally, the non-wood lignocellulose is selected from, but is not limited to, at least one of corn cobs, corn stalks, sugarcane bagasse, wheat straw, cotton stalks, cottonseed hulls, and peanut shells.

[0093] The present invention will be further described below with reference to several embodiments and comparative examples.

[0094] Example 1 Adopting such Figure 1 The apparatus shown has a hydrolysis reactor that is a cylindrical moving bed reactor with a cross-sectional area A. 平均 2m 2 The reactor is 10m high. The auxiliary feeding device 134 is a scraper F300. The feeder 142 and slag discharger 153 are both star-shaped feed valves XF300RSQ. The feeding stabilizer 152 is a pneumatic stabilizer KQP-B-100L (nitrogen source). The cone angles of the feeding hopper 130, hydrolysis reactor 150, and feeding hopper 170 are all 60°. The filter screen 161a has a 50-mesh pore size, and the filter 162a has a 100-mesh pore size. Other equipment and pipelines are standard configurations for the reactor.

[0095] like Figure 1 As shown, the crushed corn cob residue (6~15mm particle size) enters the biomass acid mixing equipment 110 through the biomass inlet 111. The acid solution (sulfuric acid, concentration of 3wt%) is sprayed into the equipment from the catalyst spray head 112. The mass ratio of corn cob residue to acid solution is 3:1. The auger 113 is started to mix the acid.

[0096] The acid-mixed corn cob residue is fed into the feeding hopper 130, which is closed by the discharge valve 141, via the tubular chain conveyor 120. Feeding is stopped when the feeding hopper 130 reaches 90% of its volume, or the feeding is switched to another feeding hopper 130 (the feeding method is the same as that of the previous feeding hopper 130). The hydrolysis reactor 150 is heated and pressurized by introducing 190℃ steam at a rate of 2.1~2.2 t / h, bringing the internal temperature of the reactor 150 to 180℃ and the pressure to 0.9 MPa. The feeding valve 131a above the already loaded feeding hopper 130 and the discharging valve 141 below are closed. High-pressure nitrogen is then introduced into the feeding hopper 130 through the first high-pressure carrier gas delivery pipe 132 until the pressure in the feeding hopper 130 reaches 0.95 MPa, at which point the nitrogen is shut off. The discharging valve 141 is then opened, initiating a continuous reaction. Once the feeding hopper 130 is completely discharged, the process is switched to another feeding hopper 170 that has been fully loaded and filled with nitrogen, continuing the discharge cycle.

[0097] When the device first starts operating, the initial mass M0 in the reactor is 4000 kg, and the reaction is initiated. Feeding, slag discharge, and furfural material discharge are continuous. The feed rate v into the hydrolysis reactor 150 is controlled by the feeder 142. 进 It is 7.5m 3 / h, feed density ρ (after acidification of biomass raw materials) 进 200kg / m 3 (200±5kg / m) 3 Fluctuation); the slag discharge speed is controlled by the slag discharger 153, the slag discharge speed v 出 It is 6.5m 3 / h, slag density ρ 出 230±5kg / m 3 During the reaction, the material is maintained at a stacking height h of approximately 9m in the hydrolysis reactor at 150°C.

[0098] The pressure difference between the first pressure sensor 163 and the second pressure sensor 164 on the furfural vapor delivery pipeline 160 is monitored. When ΔP = P 前 -P 后 When the pressure exceeds 100 kPaA, it indicates severe coking in filter 162a, requiring pipeline switching and decoking of filter 162a. The filter should be replaced with a spare delivery pipeline connected in parallel with furfural steam delivery pipeline 160.

[0099] When the material level in the feeding hopper 170 reaches 90% of its capacity, switch the feeding hopper 170. Open the slag discharge valve 172a of the nearly full feeding hopper 170, and rely on the internal residual pressure to discharge the furfural residue material onto the conveyor belt, which is then sent to the thermal power system for incineration to produce steam, and so on.

[0100] Set the material feed stabilizer 152 to start once every 5 minutes.

[0101] The system reaches steady state. After reaching steady state, continue operating according to the above parameters and adjust v. 进 and v 出 This makes ρ = 230~350 kg / m 3And keep τ at 2.4~2.6h.

[0102] Specifically, t is the running time.

[0103] Keep v 进 and v 出 The value remains unchanged; after 300 hours of operation, ρ is approximately 310 kg / m³. 3 τ is approximately 2.6h, at which point M0' is approximately 5500kg; then v is increased. 出 =7.5m 3 / h, keep not v 进 After running for another 6 hours, ρ is approximately 231 kg / m³. 3 τ is approximately 2.4h, at which point M0'' is approximately 4150kg; then v is reduced. 出 =6.5m 3 / h, then keep v 进 and v 出 The reaction remains unchanged for 300 hours, and the cycle continues as above. The yield of furfural is monitored and calculated periodically. When the yield drops by about 10%, the reaction is stopped, the reactor is cleaned, and the next continuous reaction begins.

[0104] Sampling was performed at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 68.2%, and the calculated production was 27 tons.

[0105] The furfural yield was monitored every 10 hours. When the system continued to run for 1320 hours, the furfural yield was 58.5%, a decrease of 10% ± 0.3%. The continuous reaction was stopped immediately and the equipment was cleaned, waiting for the next continuous production.

[0106] Furfural yield = mass of furfural in furfural vapor per unit time / (mass of biomass feedstock per unit time * 0.3 * 0.727 * 100%).

[0107] Example 2 The equipment used in this embodiment is the same as that in Embodiment 1.

[0108] like Figure 1 As shown, the crushed corn cob residue (20~30mm particle size) enters the biomass acid mixing equipment 110 through the biomass inlet 111. The acid solution (sulfuric acid, concentration of 4wt%) is sprayed into the equipment from the catalyst spray head 112. The mass ratio of corn cob residue to acid solution is 2:1. The auger 113 is started to mix the acid.

[0109] The acid-mixed corn cob residue is fed into the feeding hopper 130, which is closed by the discharge valve 141, via the tubular chain conveyor 120. Feeding is stopped when the feeding hopper 130 reaches 90% of its volume, or the feeding is switched to another feeding hopper 130 (the feeding method is the same as that of the previous feeding hopper 130). The hydrolysis reactor 150 is heated and pressurized by introducing 200℃ steam at a rate of 2.2~2.3 t / h, bringing the internal temperature of the reactor 150 to 190℃ and the pressure to 1.2 MPa. The feeding valve 131a above the already loaded feeding hopper 130 and the discharging valve 141 below are closed. High-pressure nitrogen is then introduced into the feeding hopper 130 through the first high-pressure carrier gas delivery pipe 132 until the pressure in the feeding hopper 130 reaches 1.22 MPa, at which point the nitrogen is shut off. The discharging valve 141 is then opened, initiating a continuous reaction. Once the feeding hopper 130 is completely discharged, the process is switched to another feeding hopper 170 that has been fully loaded and filled with nitrogen, continuing the discharge cycle.

[0110] When the device first starts operating, the initial mass M0 in the reactor is 3000 kg, and the reaction is initiated. Feeding, slag discharge, and furfural material discharge are continuous. The feed rate v into the hydrolysis reactor 150 is controlled by the feeder 142. 进 9.0m 3 / h, feed density ρ (after acidification of biomass raw materials) 进 150kg / m 3 (150±5kg / m) 3 Fluctuation); the slag discharge speed is controlled by the slag discharger 153, the slag discharge speed v 出 It is 7.5m 3 / h, slag density ρ 出 180±5kg / m 3 During the reaction, the material is maintained at a stacking height h of approximately 9m in the hydrolysis reactor at 150°C.

[0111] The pressure difference between the first pressure sensor 163 and the second pressure sensor 164 on the furfural vapor delivery pipeline 160 is monitored. When ΔP = P 前 -P 后 When the pressure exceeds 100 kPaA, it indicates severe coking in filter 162a, requiring pipeline switching and decoking of filter 162a. The filter should be replaced with a spare delivery pipeline connected in parallel with furfural steam delivery pipeline 160.

[0112] When the material level in the feeding hopper 170 reaches 90% of its capacity, switch the feeding hopper 170. Open the slag discharge valve 172a of the nearly full feeding hopper 170, and rely on the internal residual pressure to discharge the furfural residue material onto the conveyor belt, which is then sent to the thermal power system for incineration to produce steam, and so on.

[0113] Set the material feed stabilizer 152 to start once every 5 minutes.

[0114] The system reaches steady state. After reaching steady state, continue operating according to the above parameters and adjust v. 进 and v 出 This makes ρ = 200~300 kg / m 3 And keep τ at 2.0~2.1h.

[0115] Sampling was performed at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 63.5%, and the calculated production was 23 tons.

[0116] The furfural yield was monitored every 10 hours. When the system continued to run for 1230 hours, the furfural yield was 53.6%, a decrease of 10% ± 0.3%. The continuous reaction was stopped immediately and the equipment was cleaned, waiting for the next continuous production.

[0117] Example 3 The equipment used in this embodiment is the same as that in Embodiment 1.

[0118] like Figure 1 As shown, the crushed corn cob residue (6~10mm particle size) enters the biomass acid mixing equipment 110 through the biomass inlet 111. The acid solution (acetic acid, concentration of 6wt%) is sprayed into the equipment from the catalyst spray head 112. The mass ratio of corn cob residue to acid solution is 5:1. The auger 113 is started to mix the acid.

[0119] The acid-mixed corn cob residue is fed into the feeding hopper 130, which is closed by the discharge valve 141, via the tubular chain conveyor 120. Feeding is stopped when the feeding hopper 130 reaches 90% of its volume, or the feeding is switched to another feeding hopper 130 (the feeding method is the same as that of the previous feeding hopper 130). The hydrolysis reactor 150 is heated and pressurized by introducing 180℃ steam at a rate of 2.1~2.2 t / h, resulting in a temperature of 170℃ and a pressure of 0.7 MPa inside the reactor 150. The feeding valve 131a above the already loaded feeding hopper 130 and the discharging valve 141 below are closed. High-pressure nitrogen is then introduced into the feeding hopper 130 through the first high-pressure carrier gas delivery pipe 132 until the pressure in the feeding hopper 130 reaches 0.8 MPa, at which point the nitrogen is shut off. The discharging valve 141 is then opened, initiating a continuous reaction. Once the feeding hopper 130 is completely discharged, the process is repeated with another feeding hopper 170 that has been fully loaded and filled with nitrogen. This cycle continues.

[0120] When the device first starts operating, the initial mass M0 in the reactor is 6000 kg, and the reaction is initiated. Feeding, slag discharge, and furfural material discharge are continuous. The feed rate v into the hydrolysis reactor 150 is controlled by the feeder 142. 进 It is 5.0m3 / h, feed density ρ (after acidification of biomass raw materials) 进 300kg / m 3 (300±5kg / m) 3 Fluctuation); the slag discharge speed is controlled by the slag discharger 153, the slag discharge speed v 出 It is 4.5m 3 / h, slag density ρ 出 320±5kg / m 3 During the reaction, the material is maintained at a stacking height h of approximately 9m in the hydrolysis reactor at 150°C.

[0121] The pressure difference between the first pressure sensor 163 and the second pressure sensor 164 on the furfural vapor delivery pipeline 160 is monitored. When ΔP = P 前 -P 后 When the pressure exceeds 100 kPaA, it indicates severe coking in filter 162a, requiring pipeline switching and decoking of filter 162a. The filter should be replaced with a spare delivery pipeline connected in parallel with furfural steam delivery pipeline 160.

[0122] When the material level in the feeding hopper 170 reaches 90% of its capacity, switch the feeding hopper 170. Open the slag discharge valve 172a of the nearly full feeding hopper 170, and rely on the internal residual pressure to discharge the furfural residue material onto the conveyor belt, which is then sent to the thermal power system for incineration to produce steam, and so on.

[0123] Set the material feed stabilizer 152 to start once every 5 minutes.

[0124] The system reaches steady state. After reaching steady state, continue operating according to the above parameters and adjust v. 进 and v 出 This makes ρ = 250~400 kg / m 3 And keep τ at 3.6~3.8h.

[0125] Samples were taken at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 54.1%, and the calculated production was 21 tons.

[0126] The furfural yield was monitored every 10 hours. When the system continued to run for 1130 hours, the furfural yield was 44.2%, a decrease of 10% ± 0.3%. The continuous reaction was stopped immediately and the equipment was cleaned.

[0127] Furfural yield = mass of furfural in furfural vapor per unit time / (mass of biomass feedstock per unit time * 0.3 * 0.727 * 100%).

[0128] Example 4 This embodiment is basically the same as Embodiment 1, except that the biomass raw material is replaced with corn straw.

[0129] Furfural yield % = mass of furfural in furfural vapor per unit time / (mass of biomass feedstock per unit time * 0.12 * 0.727 * 100%).

[0130] Samples were taken at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 49.6%, and the calculated production was 7 tons.

[0131] The furfural yield was monitored every 10 hours. When the system continued to run for 1180 hours, the furfural yield was 38.9%, a decrease of 10.7%. The continuous reaction was stopped immediately and the equipment was cleaned.

[0132] This embodiment uses corn stalks as raw material. Compared with corn cobs as raw material, the characteristics of this biomass raw material result in a lower furfural yield.

[0133] Example 5 This embodiment is basically the same as embodiment 1, except that the biomass raw material is replaced with sugarcane bagasse.

[0134] Furfural yield % = mass of furfural in furfural vapor per unit time / (mass of biomass feedstock per unit time * 0.23 * 0.727 * 100%).

[0135] Sampling was performed at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 55.1%, and the calculated production was 16 tons.

[0136] The furfural yield was monitored every 10 hours. When the system continued to run for 1080 hours, the furfural yield was 45.8%, a decrease of 10% ± 0.3%. The continuous reaction was stopped immediately and the equipment was cleaned.

[0137] This embodiment uses sugarcane bagasse as raw material. Compared with corn cob as raw material, the characteristics of this biomass raw material result in a lower furfural yield.

[0138] Example 6 This embodiment is basically the same as embodiment 1, except that: The pressure inside the hydrolysis reactor 150 is controlled at 0.9 MPa, and the pressure in the feeding hopper 130 is controlled at 0.91 MPa.

[0139] Sampling was performed at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 59.3%, and the calculated production was 22 tons.

[0140] In this embodiment, the pressure difference between the feeding hopper 130 and the hydrolysis reactor 150 is controlled at 0.01 MPa. If the pressure difference is insufficient, furfural vapor in the reactor will escape to the feeding hopper, increasing the residence time of aldehyde vapor and leading to an increase in side reactions, thereby reducing the yield compared to Example 1.

[0141] Example 7 This embodiment is basically the same as Embodiment 1, except that: The feed rate v into the hydrolysis reactor 150 is controlled by the feeder 142. 进 3.5m 3 / h, feed (acid-mixed biomass feedstock); the slag discharge speed is controlled by the slag discharger 153, slag discharge speed v 出 3m 3 / h. After the system reaches steady state, adjust vin and vout to keep ρ between 230 and 350 kg / m2. 3 τ is between 5.1 and 5.5 hours.

[0142] Sampling was performed at regular intervals, and the furfural content was analyzed by gas chromatography. The furfural yield was calculated. After 60 hours of system operation, the furfural yield was 65.4%. After another 120 hours of system operation, the furfural yield was 62.4%, and the calculated production was 12 tons.

[0143] The furfural yield was monitored every 10 hours. When the system continued to run for 720 hours, the furfural yield was 56.1%, a decrease of 9.3%. The continuous reaction was stopped immediately and the equipment was cleaned.

[0144] Although the furfural yield reached 65% after 60 hours of operation in this embodiment, the furfural yield decreased faster than in Example 1 as the system continued to run. This is likely due to the increased residence time of furfural vapor in the reactor, which led to an increase in side reactions. The yield reduction became more pronounced as the operating time increased.

[0145] Example 8 This embodiment is basically the same as Embodiment 1, except that: After the system reaches steady state, v is not adjusted. 出 .

[0146] Samples were taken at regular intervals, and the furfural content was analyzed by gas chromatography. The yield of furfural was calculated. After the system ran for 120 hours, the furfural yield was monitored to be 55.7%, and the calculated output was 22 tons.

[0147] The furfural yield was monitored every 10 hours. When the system continued to run for 780 hours, the furfural yield was 45.6%, a decrease of 10.1%. The continuous reaction was stopped immediately and the equipment was cleaned.

[0148] This embodiment does not regulate v. 出 This can lead to overly compacted material packing, resulting in uneven contact between the material and steam, and consequently, incomplete reaction, leading to a lower yield compared to Example 1. Furthermore, the overly compacted material packing in this example also prevents the generated furfural vapor from dissipating effectively, increasing side reactions and thus reducing the overall system uptime.

[0149] Comparative Example This comparative example provides a conventional batch process for producing furfural, implemented using the equipment provided in Example 1 of this application, and simulating the existing batch process by controlling the equipment operation mode.

[0150] In this comparative example, the equipment is controlled to operate discontinuously. After the material is loaded into the reactor, the inlet and outlet of the reactor are sealed, and the material is discharged after the reaction is complete.

[0151] The operating parameters are basically the same as in Example 1, except that: no parameters involving continuous operation are adjusted, i.e., no v. 进 ρ 进 v 出、 ρ 进 Parameters, etc. In this comparative example, the residence time of the material in the reactor was 2.4 h.

[0152] The system runs for 3.4 hours at a time, and after 120 hours of operation, the furfural yield is 50.3%, with a calculated output of 14 tons.

[0153] In summary, the furfural continuous production apparatus 100 and method provided in this embodiment of the invention can achieve continuous furfural production while effectively avoiding incomplete reaction or material blockage. Compared with the intermittent process of the hydrolysis reactor 150 of the same size, it can significantly improve the production capacity.

[0154] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuous furfural production apparatus, characterized in that, include: Multiple feeding bins, each feeding bin having a first feeding port at the top and a discharging port at the bottom; A hydrolysis reactor is located below the plurality of feeding hoppers. The hydrolysis reactor is provided with a high-temperature steam inlet at the bottom, a second feed inlet and a product outlet at the top, and a first slag discharge outlet at the bottom. All the discharge outlets are connected to the second feed inlet via a discharge pipeline. Multiple feeding hoppers, each feeding hopper having a slag inlet at the top and a second slag outlet at the bottom; the first slag outlet and all the slag inlets are connected by a slag discharge pipeline; The feeding control system is used to control the opening and closing of the pipeline between each of the feeding ports and the second feed port, and the feeding rate of the feed hopper when the pipeline is open; it is also used to control the opening and closing of the pipeline between each of the slag inlets and the first slag outlets, and the slag discharge rate of the hydrolysis reactor when the pipeline is open.

2. The furfural continuous production apparatus according to claim 1, characterized in that, It also includes at least one of the following technical features (1) to (3): (1) The feeding control system further includes a feeder; the feeder is installed on the feeding pipeline and is used to control the feeding rate of each feeding bin; (2) The feeding control system further includes a slag discharger, which is connected to the first slag discharge port and is used to control the slag discharge rate of the hydrolysis reactor. (3) The feeding control system includes multiple feeding valves. At least one feeding valve is provided on the pipeline connecting each feeding port and the second feeding port. The opening and closing of the corresponding pipeline is achieved by adjusting the feeding valve.

3. The furfural continuous production apparatus according to claim 1 or 2, characterized in that, It also includes at least one of the following technical features (1) to (6): (1) Each of the feeding bins is equipped with an auxiliary unloading device at its bottom; (2) A feed stabilizer is provided at the bottom of the hydrolysis reactor; (3) Each of the feeding hoppers is provided with an exhaust vent at the top; (4) Each of the feeding hoppers is also provided with a first high-pressure carrier gas inlet; (5) The bottom of each feeding hopper, the bottom of the hydrolysis reactor and / or the bottom of each discharging hopper is conical with a cone angle of 30~75°; (6) Each of the feeding bins is provided with a second high-pressure carrier gas inlet.

4. The furfural continuous production apparatus according to claim 1 or 2, characterized in that, The product outlet is connected to a furfural vapor delivery pipeline. The furfural vapor delivery pipeline includes a main line and multiple branch lines connected in parallel to the main line. The main line is equipped with a filter screen with a pore size of 20-60 mesh, and each branch line is equipped with a filter with a pore size of 80-120 mesh. Optionally, in the furfural vapor delivery pipeline, a first pressure sensor and a second pressure sensor are respectively installed before and after each of the filters; Optionally, on each branch line, a shut-off valve one is provided at the front end of the filter, a shut-off valve two is provided at the rear end, a purge steam branch is provided between the filter and the shut-off valve one, and a vent branch is provided between the filter and the shut-off valve two.

5. The furfural continuous production apparatus according to claim 1 or 2, characterized in that, The feeding control system includes multiple slag discharge valves. At least one slag discharge valve is provided on the pipeline connecting each slag inlet and the first slag outlet. The opening and closing of the pipeline is achieved by controlling the opening and closing of the slag discharge valve. Optionally, each of the second slag discharge ports is connected to a slag discharge pipe, and the slag discharge pipe is equipped with a slag discharge valve.

6. The furfural continuous production apparatus according to claim 1 or 2, characterized in that, The furfural continuous production unit also includes a biomass acid mixing device, with a feed pipe connected to each of the first feed inlets, and the discharge outlet of the biomass acid mixing device is connected to each of the feed pipes through a conveying mechanism. Optionally, the conveying mechanism is a tubular chain conveyor.

7. A continuous production method for furfural, characterized in that, The process is carried out using the furfural continuous production apparatus as described in any one of claims 1 to 6, comprising: The multiple feeding hoppers are alternately and continuously feeding materials into the hydrolysis reactor. The materials entering the hydrolysis reactor from the feeding hoppers are biomass raw materials that have been mixed with acid. While the feed hopper is feeding the hydrolysis reactor, high-temperature steam is introduced into the high-temperature steam inlet, so that the acid-mixed biomass raw material reacts with the high-temperature steam in the hydrolysis reactor to generate furfural steam. The generated furfural steam is discharged from the product outlet, and the generated residue is discharged into the multiple feed hoppers that are used alternately.

8. The continuous production method of furfural according to claim 7, characterized in that, During the reaction, the bulk density ρ of the material in the hydrolysis reactor is controlled to be 200~450 kg / m³. 3 ; Preferably, ρ is controlled to be 200~450 kg / m³ by the following formula (1). 3 : Equation (1): ； In equation (1), ρ 进 ρ is the density of the material entering the hydrolysis reactor. 出 To determine the density of the slag from the hydrolysis reactor, v 进 v is the velocity of the material entering the hydrolysis reactor. 出 The velocity of material discharged from the hydrolysis reactor; t is the production run time; M0 is the initial material mass in the hydrolysis reactor; h is the height of the material in the hydrolysis reactor; A 平均 This represents the average cross-sectional area of ​​the hydrolysis reactor; Optionally, v 进 2~12 m 3 / h,v 出 2~12 m 3 / h, ρ 进 200~300 kg / m 3 , ρ 出 220~350 kg / m 3 ; Optionally, the high-temperature steam flow rate is 1~15 t / h; Alternatively, τ can be controlled to be 2~5h using the following equation (2): Equation (2) ； In equation (2), v 进 v is the velocity of the material entering the hydrolysis reactor. 出 V is the rate at which the material is discharged from the hydrolysis reactor, and V is the effective volume of the hydrolysis reactor. Optionally, the reaction temperature inside the hydrolysis reactor is 170~190℃, and the reaction pressure is 0.7~1.2MPa; Optionally, the temperature of the high-temperature steam introduced into the hydrolysis reactor is 180~200°C; Optionally, before feeding material from the feeding hopper into the hydrolysis reactor, an inert gas is introduced into the feeding hopper to make the pressure in the feeding hopper 0.01~0.1 MPaG higher than the pressure inside the hydrolysis reactor, and then feeding begins. Optionally, before the feeding hopper is switched to be connected to the hydrolysis reactor, inert gas is introduced into it to make the pressure of the feeding hopper 0.01~0.1 MPaG lower than the pressure inside the hydrolysis reactor.

9. The continuous production method of furfural according to claim 7 or 8, characterized in that, The biomass raw material after acid mixing is obtained by uniformly mixing the acid, which serves as a catalyst, with the biomass raw material; The acid is selected from at least one of sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, and acetic acid; Optionally, the acid is mixed with the biomass raw material in the form of an acid solution, the mass concentration of the acid solution is 2-10 wt%, and the biomass raw material and the acid solution are mixed at a mass ratio of 1-5:

1. Optionally, the particle size of the biomass raw material is 6-50 mm.

10. The continuous production method of furfural according to claim 9, characterized in that, The biomass raw materials include at least one of wood materials and non-wood lignocellulose; Optionally, the wood species of the wood material is at least one of broadleaf wood, coniferous wood, and grass; Optionally, the wood material is selected from at least one part of the leaf; Optionally, the non-wood lignocellulose is selected from at least one of corn cob, corn stalk, sugarcane bagasse, wheat straw, cotton stalk, cottonseed hull, and peanut shell.

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