Hard straw alkali hyponitrite method rapid cooking delignification system

Abstract

The utility model discloses a kind of hard straw alkaline imidogen method quick cooking delignification system, it is related to pulping papermaking technical field, main purpose is to make hard straw be softened and decomposed quickly in cooking process, create favorable conditions for cotton stick and other hard straw as pulping papermaking raw material.The main technical scheme of the utility model is as follows:hard straw alkaline imidogen method quick cooking delignification system, the device includes: the pin drum metering device, pre-steaming screw mechanism, screw feeder, T-tube, horizontal tube digester, pressure rubbing mill, vertical pot digester and spray bin connected in turn;Among them, ammonium sulfite inlet pipe and magnesium oxide inlet pipe are connected to the T-tube respectively.

Description

Technical Field

[0001] This utility model relates to the field of pulp and paper technology, and in particular to a rapid cooking and delignification system for hard straw using alkaline ammonium sulfite. Background Technology

[0002] In recent years, with the rapid development of China's paper industry, the shortage of papermaking raw materials has become a bottleneck for the industry's development. Straw resources, as a high-quality papermaking raw material, have received significant attention from major paper companies. However, the alkali lignin black liquor produced during the traditional alkaline pulping process is difficult to process, yields low returns, and can even result in losses. In recent years, the ammonium sulfite pulping process has quietly emerged. The sulfonated lignin black liquor produced during pulping is an organic fertilizer with high economic and social value. Soft straws such as wheat straw and rice straw have been successfully processed using the ammonium sulfite process to produce high-quality pulp and humic acid fertilizer, achieving good economic value. However, hard straw raw materials such as cotton stalks, hemp stalks, and bean stalks are difficult to soften and decompose during cooking due to their fiber structure, density, high lignin and hemicellulose content, surface wax layer, and complex cell wall structure. Using the traditional ammonium sulfite pulping process results in a long cooking cycle, high cooking temperature and pressure, making large-scale, automated, and continuous production difficult. Utility Model Content

[0003] In view of this, this utility model provides a rapid cooking and delignification system for hard straw using alkaline ammonium sulfide, the main purpose of which is to rapidly soften and decompose hard straw during the cooking process, creating favorable conditions for using hard straw such as cotton stalks as raw materials for pulping and papermaking.

[0004] To achieve the above objectives, this utility model mainly provides the following technical solutions:

[0005] This utility model embodiment provides a rapid delignification system for hard straw using alkaline ammonium sulfide cooking. The device includes:

[0006] The pin drum metering device, the pre-steaming screw mechanism, the screw feeder, the T-tube, the horizontal tube cooker, the pressure mill, the vertical cooker and the spray chamber are connected in sequence.

[0007] The ammonium sulfite inlet pipe and the magnesium oxide inlet pipe are respectively connected to the T-shaped pipe.

[0008] The purpose of this utility model and the technical problems to be solved can be further achieved by the following technical measures.

[0009] Optionally, it also includes a first steam pipe. The horizontal tube cooker includes a tube body and a spiral rod coaxially disposed within the tube body, and the first steam pipe is connected to the side wall of the tube body.

[0010] Optionally, a second steam pipe is also included. The vertical cooker includes a pot body, a heating pipe, and a discharge device. The heating pipe is coaxially disposed in the pot body. The second steam pipe is connected to the upper end of the heating pipe. The middle wall of the heating pipe has multiple through holes evenly distributed. The discharge device includes a first housing and a stirring shaft located in the first housing. The first housing is coaxially connected to the lower end of the pot body. The upper end of the stirring shaft is fixedly connected to spirally arranged blades. The side wall of the first housing is connected to the discharge chamber through a conveying pipe.

[0011] Optionally, it also includes a temperature-regulating liquid tank and a temperature-regulating pump, wherein the inlet of the temperature-regulating pump is connected to the temperature-regulating liquid tank and the outlet of the temperature-regulating pump is connected to the lower end of the pot body.

[0012] Optionally, the pressure grinding machine includes a second housing, a double-headed spiral rod and a grinding disc arranged sequentially within the second housing. The grinding disc includes a fixed disc and a moving disc. The fixed disc is fixedly installed within the second housing, and the moving disc rotates coaxially relative to the fixed disc. The inlet of the second housing is located above the double-headed spiral rod, and the outlet of the second housing is located below the moving disc. The inlet of the second housing is connected to the horizontal tube cooker via a first flexible connecting pipe, and the outlet of the second housing is connected to the vertical cooker via a second flexible connecting pipe.

[0013] Optionally, the screw feeder includes a third housing and a feeding screw located inside the third housing. The inlet of the third housing is connected to the pre-steaming screw mechanism, and the outlet of the third housing is connected to one side wall of the upper end of the T-tube. A cylinder is installed on the other side wall of the upper end of the T-tube, and the end of the piston rod of the cylinder is fixedly connected to a cone, which corresponds to the outlet of the third housing.

[0014] The ammonium sulfite inlet pipe and the magnesium oxide inlet pipe are respectively connected to the upper end of the T-shaped pipe.

[0015] Optionally, the upper end of the T-shaped tube, the upper end of the vertical steamer, and the upper end of the spray chamber are respectively connected to the pre-steaming spiral mechanism through exhaust pipes.

[0016] Optionally, it also includes a first regulating valve and a second regulating valve, the first regulating valve being installed in the ammonium sulfite inlet pipe and the second regulating valve being installed in the magnesium oxide inlet pipe, the first regulating valve, the second regulating valve and the pin drum metering device constituting a first interlocking control mechanism.

[0017] Optionally, it also includes a first level gauge, a second level gauge, a third level gauge, and a third regulating valve. The first level gauge, the second level gauge, and the third level gauge are sequentially installed on the upper side of the pot body, and the third regulating valve is installed on the conveying pipe. The first level gauge, the second level gauge, the third level gauge, and the third regulating valve constitute a second interlocking control mechanism.

[0018] Optionally, it also includes a fourth regulating valve, a first temperature transmitter, and a second temperature transmitter. The fourth regulating valve is installed on the second steam pipe, and the first temperature transmitter and the second temperature transmitter are sequentially installed on the side wall of the pot body. The first temperature transmitter, the second temperature transmitter, and the fourth regulating valve constitute a third interlocking control mechanism.

[0019] By employing the above technical solution, this utility model has at least the following advantages:

[0020] This device addresses the challenges of using high-density, high-lignin and hemicellulose content, waxy surface layers, and complex cell wall structures in hard straws such as cotton stalks, hemp stalks, and bean stalks, which are unfavorable for delignification via ammonium sulfite cooking. It allows for rapid softening and decomposition of hard straws during cooking. Magnesium oxide solution acts as a pH buffer, maintaining a stable pH above 8 throughout the delignification process. This allows for the use of carbon steel in cooking equipment, subsequent washing equipment, black liquor evaporation equipment, and pipework and fittings, significantly reducing equipment investment. Furthermore, the addition of magnesium improves the quality of the black liquor humic acid fertilizer, creating favorable conditions for the large-scale, high-value utilization of hard straw as a pulping and papermaking raw material. The device enables the completion of the ammonium sulfite cooking and delignification process for hard straw within 2 hours, achieving large-scale, automated, and continuous production of hard straw using this method, greatly enhancing the comprehensive utilization value of hard straw. This opens up broad prospects for the high-value comprehensive utilization of hard straws such as cotton stalks, bean stalks, and hemp stalks.

[0021] The amount of magnesium oxide added is 3-7% relative to the oven-dry raw material, and the magnesium oxide is added in the form of a suspension. Attached Figure Description

[0022] Figure 1 A schematic diagram of a rapid delignification system for hard straw using alkaline ammonium sulfide method provided for an embodiment of this utility model;

[0023] Figure 2 This is a partial sectional view of a pressure grinding machine;

[0024] Figure 3 This is a top view of the screw feeder;

[0025] Figure 4 for Figure 1 Enlarged view of section A;

[0026] Figure 5 A schematic diagram of a vertical steam cooker;

[0027] Figure 6 This is a top view of the unloader;

[0028] Figure 7 for Figure 1 Enlarged view of section B;

[0029] Figure 8 This is a schematic diagram of a horizontal tube cooker.

[0030] The reference numerals in the accompanying drawings include: 1. Pin drum metering device; 2. Pre-steaming screw mechanism; 3. Screw feeder; 4. T-tube; 5. Horizontal tube cooker; 6. Pressure mill; 7. Vertical cooker; 8. Discharge chamber; 9. Ammonium sulfite inlet pipe; 10. Magnesium oxide inlet pipe; 11. First steam pipe; 501. Pipe body; 502. Screw rod; 12. Second steam pipe; 701. Pot body; 702. Heating tube; 703. Through hole; 13. Unloader; 13. First shell; 1301. Blade; 1302. Hydraulic... Motor 1303, temperature regulating liquid tank 14, temperature regulating pump 15, second housing 601, double-headed screw 602, fixed plate 603, moving plate 604, third housing 301, feeding screw 302, cylinder 16, cone 17, exhaust pipe 18, first regulating valve 19, second regulating valve 20, first level gauge 21, second level gauge 22, third level gauge 23, third regulating valve 24, fourth regulating valve 25, first temperature transmitter 26, second temperature transmitter 27. Detailed Implementation

[0031] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the specific implementation methods, structures, features, and effects according to this utility model application are described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 As shown, one embodiment of this utility model provides a rapid delignification system for hard straw using alkaline ammonium sulfide cooking, which includes:

[0034] The pin drum metering device 1, the pre-steaming screw mechanism 2, the screw feeder 3, the T-tube 4, the horizontal tube cooker 5, the pressure grinding machine 6, the vertical cooker 7, and the spray chamber 8 are connected in sequence.

[0035] The ammonium sulfite inlet pipe 9 and the magnesium oxide inlet pipe 10 are respectively connected to the T-shaped pipe 4.

[0036] The working process of the alkaline ammonium sulfite rapid cooking delignification system for hard straw is as follows:

[0037] This device addresses the challenges of using high-density, high-lignin and hemicellulose content, waxy surface layers, and complex cell wall structures in hard straws such as cotton stalks, hemp stalks, and bean stalks, which are unfavorable for delignification via ammonium sulfite cooking. It allows for rapid softening and decomposition of hard straws during cooking. Magnesium oxide solution acts as a pH buffer, maintaining a stable pH above 8 throughout the delignification process. This allows for the use of carbon steel in cooking equipment, subsequent washing equipment, black liquor evaporation equipment, and pipework and fittings, significantly reducing equipment investment. Furthermore, the addition of magnesium improves the quality of the black liquor humic acid fertilizer, creating favorable conditions for the large-scale, high-value utilization of hard straw as a pulping and papermaking raw material. The device enables the completion of the ammonium sulfite cooking and delignification process for hard straw within 2 hours, achieving large-scale, automated, and continuous production of hard straw using this method, greatly enhancing the comprehensive utilization value of hard straw. This opens up broad prospects for the high-value comprehensive utilization of hard straws such as cotton stalks, bean stalks, and hemp stalks.

[0038] The amount of magnesium oxide added is 3-7% relative to the oven-dry raw material, and the magnesium oxide is added in the form of a suspension.

[0039] like Figure 1 and Figure 8 As shown, in a specific embodiment, it also includes a first steam pipe 11. The horizontal tube cooker 5 includes a tube body 501 and a spiral rod 502 coaxially disposed in the tube body 501. The first steam pipe 11 is connected to the side wall of the tube body 501.

[0040] In this embodiment, the horizontal tube digester 5 is a primary digester. The material with added ammonium sulfite and magnesium oxide solutions and some steam is further mixed and heated in the horizontal tube digester 5. The spiral rod 502 inside the equipment is a variable diameter and variable pitch spiral. The special spiral blade 1302 structure makes the volume ratio of the material in the horizontal tube digester 5 reach 70-75%, and the material can be fully mixed with the solution and steam under the stirring action of the blade 1302. This is conducive to the material reacting evenly in the equipment for a longer time, so that the material can initially remove lignin and achieve a better softening effect. The material is heated to 140-150°C in the tube body 501.

[0041] like Figure 1 , Figure 4 , Figure 5 , Figure 6As shown, in a specific embodiment, a second steam pipe 12 is also included. The vertical cooker 7 includes a pot body 701, a heating pipe 702, and a discharge device 13. The heating pipe 702 is coaxially arranged inside the pot body 701. The second steam pipe 12 is connected to the upper end of the heating pipe 702. The middle wall of the heating pipe 702 is evenly distributed with multiple through holes 703. The discharge device 13 includes a first housing 1301 and a stirring shaft located inside the first housing 1301. The first housing 1301 is coaxially connected to the lower end of the pot body 701. The upper end of the stirring shaft is fixedly connected to spirally arranged blades 1302. The side wall of the first housing 1301 is connected to the discharge chamber 8 through a conveying pipe.

[0042] In this embodiment, steam flows sequentially through the second steam pipe 12 and the heating pipe 702, and finally mixes into the material in the pot body 701 through multiple through holes 703. The heating pipe 702 is coaxially arranged inside the pot body 701, which guides the settling of the material inside the pot body 701.

[0043] A hydraulic motor 1303 is fixedly installed at the lower end of the first housing 1301. The output shaft of the hydraulic motor 1303 is connected to the lower end of the stirring shaft. The upper end of the stirring shaft is fixedly connected to the blade. Multiple blades 1302 are fixedly connected to the blade. The multiple blades 1302 are arranged in a spiral shape. When the blades 1302 rotate, they drive the slurry to converge towards the center. On the radial section of the first housing 1301, the slurry settles evenly.

[0044] Compared to the horizontal tube cooker 5, the vertical cooker 7 has a larger volume and requires less power, ensuring the fullness of the delignification reaction of the material while saving energy and reducing consumption.

[0045] The vertical cooker 7 can heat the material through the intermediate heating tube 702, so that the material can maintain the temperature of delignification reaction during the heat preservation stage.

[0046] Although this device uses a rapid cooking and delignification process, the ammonium sulfite pulping method is fundamentally different from the alkali and sulfate pulping methods. The traditional sulfite pulping method for hard straw pulping requires 4-6 hours of heat preservation, while the process and equipment of this device can shorten it to 1.5-2 hours. The material from the pressure mill 6 reaches a good temperature and mixing condition, and the material enters the rapid lignin removal stage. The material is kept warm in the vertical cooker 7 for about 1.5 hours. If the temperature drops during the heat preservation process, steam is added through the heating tube 702 for fine-tuning to achieve the best reaction conditions.

[0047] like Figure 1As shown, in a specific embodiment, it also includes a temperature-regulating liquid tank 14 and a temperature-regulating pump 15. The inlet of the temperature-regulating pump 15 is connected to the temperature-regulating liquid tank 14, and the outlet of the temperature-regulating pump 15 is connected to the lower end of the pot body 701.

[0048] In this embodiment, specifically, the temperature regulating liquid in the temperature regulating liquid tank 14 is transported to the lower end of the pot body 701 by the temperature regulating pump 15. On the one hand, the temperature of the lower space of the vertical pot cooker 7 is reduced. On the other hand, the high-pressure fluid pumped by the temperature regulating pump 15 provides power to transport the material to the discharge chamber 8 to achieve cold discharge.

[0049] Specifically, after the K value is qualified, a temperature-regulating liquid is added to the bottom of the pot 701 to lower the slurry temperature to 90-95℃, thus achieving cold spraying.

[0050] like Figure 1 and Figure 2 As shown, in a specific embodiment, the pressure grinding machine 6 includes a second housing 601, a double-headed spiral rod 602 and a grinding disc arranged sequentially within the second housing 601. The grinding disc includes a fixed disc 603 and a moving disc 604. The fixed disc 603 is fixedly installed within the second housing 601, and the moving disc 604 rotates coaxially relative to the fixed disc 603. The inlet of the second housing 601 is located above the double-headed spiral rod 602, and the outlet of the second housing 601 is located below the moving disc 604. The inlet of the second housing 601 is connected to the horizontal tube cooker 5 through a first flexible connecting pipe, and the outlet of the second housing 601 is connected to the vertical cooker 7 through a second flexible connecting pipe.

[0051] In this embodiment, specifically, the material discharged from the horizontal tube cooker 5 enters the second shell 601 and reaches the grinding disc under the drive of the double-headed spiral rod 602. During the relative rotation of the moving disc 604 and the fixed disc 603, the material is rubbed into filaments.

[0052] Specifically, the pressure grinding machine 6 is located between the horizontal tube steamer and the vertical steamer. It grinds the material that has undergone preliminary delignin removal and softening in the horizontal tube steamer 5 into cotton wool and filaments, which alters the structure of pectin, wax layer, and some cell walls. The chemical solution and the material are fully combined during the grinding process, creating favorable conditions for rapid lignin removal. Grinding after full softening can greatly reduce the damage to the fibers by the grinding discs during the grinding process, and the physical properties of the fibers can be fully guaranteed.

[0053] Specifically, the pressure grinding machine 6 uses a large toothed grinding disc structure that primarily uses rubbing and secondarily uses grinding. During operation, the gap between the fixed disc 603 and the moving disc 604 is relatively large, generally 1-1.5mm.

[0054] Specifically, the power consumption of the pressure grinding machine 6 is about 1 / 3 to 1 / 2 of that of the traditional high-concentration mill.

[0055] Specifically, during the grinding process of the pressure grinding mill 6, some of the mechanical energy is converted into heat energy, generating a certain amount of steam, which causes the material temperature to rise rapidly to 160-165℃, reaching the optimal temperature for delignification in ammonium sulfite pulping, thus reducing the consumption of fresh steam.

[0056] Specifically, the inlet of the second housing 601 is connected to the horizontal tube cooker 5 through the first flexible connecting pipe, and the outlet of the second housing 601 is connected to the vertical cooker 7 through the second flexible connecting pipe. This firstly eliminates the impact of equipment vibration during the operation of the pressure grinding machine 6 on the upper and lower cookers, and also compensates for the thermal expansion of the upper and lower continuous cooking equipment.

[0057] like Figure 3 , Figure 7 As shown, in a specific embodiment, the screw feeder 3 includes a third housing 301 and a feeding screw 302 located inside the third housing 301. The inlet of the third housing 301 is connected to the pre-steaming screw mechanism 2, and the outlet of the third housing 301 is connected to one side wall of the upper end of the T-tube 4. A cylinder 16 is installed on the other side wall of the upper end of the T-tube 4. The end of the piston rod of the cylinder 16 is fixedly connected to a cone 17, and the cone 17 corresponds to the outlet of the third housing 301.

[0058] The ammonium sulfite inlet pipe 9 and the magnesium oxide inlet pipe 10 are respectively connected to the upper end of the T-shaped pipe 4.

[0059] In this embodiment, specifically, the feeding screw 302 is a variable diameter and variable pitch screw, and the third housing 301 is a conical tube. Under the push of the feeding screw 302, the material is compressed by the variable diameter and variable pitch screw and the conical tube. The dryness of the compressed material sheet forming the material plug is greater than 40%, and the material plug is formed at the discharge port of the third housing 301 to achieve the purpose of gas-liquid sealing and prevent backflow.

[0060] When the process or equipment feeding of this device is abnormal, the piston rod of the control cylinder 16 extends, driving the cone 17 to block the discharge port of the third housing 301 and stop feeding.

[0061] Specifically, it also includes a filter screen, which is set on the lower side wall of the third housing 301. Under the compression of the variable diameter and pitch spiral and the conical tube, the water in the material is squeezed out and discharged from the third housing 301 through the filter screen, so that the dryness of the material is greater than 40%. On this basis, the material is then mixed with ammonium sulfite and magnesium oxide solution to ensure the concentration of the drug solution.

[0062] like Figure 1As shown, in a specific embodiment, the upper end of the T-shaped tube 4, the upper end of the vertical steamer 7, and the upper end of the spray chamber 8 are respectively connected to the pre-steaming spiral mechanism 2 through the exhaust pipe 18.

[0063] In this embodiment, specifically, the exhaust pipes 18 of the T-tube 4, the vertical cooker 7, and the spray chamber 8 are each equipped with control valves. When the pressure at the top of the T-tube 4, the vertical cooker 7, and the spray chamber 8 is too high, the steam can be automatically discharged by adjusting the opening of their respective control valves, allowing the steam to enter the preheating spiral mechanism.

[0064] like Figure 1 As shown, in a specific embodiment, it also includes a first regulating valve 19 and a second regulating valve 20. The first regulating valve 19 is installed on the ammonium sulfite inlet pipe 9, and the second regulating valve 20 is installed on the magnesium oxide inlet pipe 10. The first regulating valve 19, the second regulating valve 20 and the pin drum meter 1 constitute a first interlocking control mechanism.

[0065] In this embodiment, specifically, the pin drum metering device 1 is a feeding and metering device for qualified material flakes. Qualified material flakes refer to hard straw such as cotton stalks, hemp stalks, and bean stalks that have been crushed, screened, washed, and preliminarily dehydrated, and have a moisture content of about 80%, suitable for entering the screw feeder 3. The main components of the pin drum metering device 1 are the outer shell and two opposing rotating drum-shaped rotors with feeding teeth. The upper chute of the pin drum metering device 1 is always in a full state. The rotation speed of the two rotors determines the amount of raw material fed, which is the direct basis for the subsequent cooking system capacity and the amount of medicine added.

[0066] Specifically, the speed sensor of the pin drum meter 1 monitors the rotational speed of the rotor and transmits the feeding amount electrical signal of the pin drum meter 1 to the controller. The controller adjusts the opening of the first regulating valve 19 and the second regulating valve 20 according to the electrical signal, thereby adjusting the proportion of medicine added to the material.

[0067] like Figure 1 As shown, in a specific embodiment, it also includes a first level gauge 21, a second level gauge 22, a third level gauge 23, and a third regulating valve 24. The first level gauge 21, the second level gauge 22, and the third level gauge 23 are sequentially installed on the upper side of the pot body 701, and the third regulating valve 24 is installed on the conveying pipe. The first level gauge 21, the second level gauge 22, the third level gauge 23, and the third regulating valve 24 constitute a second interlocking control mechanism.

[0068] In this embodiment, specifically, the first level gauge 21, the second level gauge 22, and the third level gauge 23 are all tension level gauges. The first level gauge 21, the second level gauge 22, and the third level gauge 23 transmit electrical signals to the controller. The controller adjusts the opening of the third regulating valve 24, thereby maintaining the liquid level of the pot body 701 between the first level gauge 21 and the third level gauge 23 through integral feedback control.

[0069] like Figure 1 As shown, in a specific embodiment, it also includes a fourth regulating valve 25, a first temperature transmitter 26, and a second temperature transmitter 27. The fourth regulating valve 25 is installed on the second steam pipe 12, and the first temperature transmitter 26 and the second temperature transmitter 27 are sequentially installed on the side wall of the pot body 701. The first temperature transmitter 26, the second temperature transmitter 27, and the fourth regulating valve 25 constitute a third interlocking control mechanism.

[0070] In this embodiment, specifically, the first temperature sensor is installed on the upper side wall of the pot body 701, and the second temperature sensor is installed on the lower side wall of the pot body 701. The first temperature sensor and the second temperature sensor respectively transmit electrical signals to the controller. When the electrical signal is less than the lower limit of the set value of the pot body 701 temperature, the controller increases the opening of the fourth regulating valve 25.

[0071] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A hard stalk alkali imidogen method rapid cooking delignification system, characterized in that, include: The pin drum metering device, the pre-steaming screw mechanism, the screw feeder, the T-tube, the horizontal tube cooker, the pressure mill, the vertical cooker and the spray chamber are connected in sequence. The ammonium sulfite inlet pipe and the magnesium oxide inlet pipe are respectively connected to the T-shaped pipe.

2. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 1, characterized in that, It also includes a first steam pipe. The horizontal tube cooker includes a tube body and a spiral rod coaxially disposed within the tube body. The first steam pipe is connected to the side wall of the tube body.

3. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 1, characterized in that, It also includes a second steam pipe. The vertical cooker includes a pot body, a heating pipe, and a discharge device. The heating pipe is coaxially arranged in the pot body. The second steam pipe is connected to the upper end of the heating pipe. The middle wall of the heating pipe has multiple through holes evenly distributed. The discharge device includes a first shell and a stirring shaft located in the first shell. The first shell is coaxially connected to the lower end of the pot body. The upper end of the stirring shaft is fixedly connected to spirally arranged blades. The side wall of the first shell is connected to the discharge chamber through a conveying pipe.

4. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 3, characterized in that, It also includes a temperature-regulating liquid tank and a temperature-regulating pump, with the inlet of the temperature-regulating pump connected to the temperature-regulating liquid tank and the outlet of the temperature-regulating pump connected to the lower end of the pot body.

5. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 1, characterized in that, The pressure grinding machine includes a second housing, a double-headed spiral rod and a grinding disc arranged sequentially within the second housing. The grinding disc includes a fixed disc and a moving disc. The fixed disc is fixedly installed within the second housing, and the moving disc rotates coaxially relative to the fixed disc. The inlet of the second housing is located above the double-headed spiral rod, and the outlet of the second housing is located below the moving disc. The inlet of the second housing is connected to the horizontal tube cooker via a first flexible connecting pipe, and the outlet of the second housing is connected to the vertical cooker via a second flexible connecting pipe.

6. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 1, characterized in that, The screw feeder includes a third housing and a feeding screw located inside the third housing. The inlet of the third housing is connected to the pre-steaming screw mechanism, and the outlet of the third housing is connected to one side wall of the upper end of the T-tube. A cylinder is installed on the other side wall of the upper end of the T-tube. The end of the piston rod of the cylinder is fixedly connected to a cone, and the cone corresponds to the outlet of the third housing. The ammonium sulfite inlet pipe and the magnesium oxide inlet pipe are respectively connected to the upper end of the T-shaped pipe.

7. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 1, characterized in that, The upper end of the T-shaped tube, the upper end of the vertical steamer, and the upper end of the spray chamber are respectively connected to the pre-steaming spiral mechanism through exhaust pipes.

8. The rapid delignification system for hard straw using alkaline ammonium sulfide method according to any one of claims 1 to 7, characterized in that, It also includes a first regulating valve and a second regulating valve. The first regulating valve is installed in the ammonium sulfite inlet pipe, and the second regulating valve is installed in the magnesium oxide inlet pipe. The first regulating valve, the second regulating valve, and the pin drum metering device constitute a first interlocking control mechanism.

9. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 3, characterized in that, It also includes a first level gauge, a second level gauge, a third level gauge, and a third regulating valve. The first level gauge, the second level gauge, and the third level gauge are sequentially installed on the upper side of the pot body, and the third regulating valve is installed on the conveying pipe. The first level gauge, the second level gauge, the third level gauge, and the third regulating valve constitute a second interlocking control mechanism.

10. The rapid delignification system for hard straw using alkaline ammonium sulfite method according to claim 3, characterized in that, It also includes a fourth regulating valve, a first temperature transmitter, and a second temperature transmitter. The fourth regulating valve is installed on the second steam pipe, and the first temperature transmitter and the second temperature transmitter are sequentially installed on the side wall of the pot body. The first temperature transmitter, the second temperature transmitter, and the fourth regulating valve constitute a third interlocking control mechanism.

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