Rapid cooking delignification system for hard straw by alkaline ammonium sulfite method

Abstract

The invention discloses a system for quickly cooking and delignifying hard straws by an alkaline ammonium sulfite method, relates to the technical field of pulping and papermaking, and mainly aims to quickly soften and decompose the hard straws in the cooking process and create favorable conditions for taking the hard straws such as cotton stalks as pulping and papermaking raw materials. According to the main technical scheme, the system for rapidly cooking and delignifying the hard straw through the alkaline ammonium sulfite method comprises a pin drum meter, a pre-steaming spiral mechanism, a spiral feeder, a T-shaped pipe, a transverse pipe digester, a pressure rubbing and grinding machine, a vertical boiler digester and a spraying bin which are connected in sequence, wherein the pin drum meter, the pre-steaming spiral mechanism, the spiral feeder, the T-shaped pipe, the transverse pipe digester, the pressure rubbing and grinding machine, the vertical boiler digester and the spraying bin are connected in sequence; wherein the ammonium sulfite liquid inlet pipe and the magnesium oxide liquid inlet pipe are respectively connected to the T-shaped pipe.

Description

Technical Field

[0001] The invention relates to the technical field of pulping and papermaking, in particular to a hard straw alkaline ammonium sulfite method rapid cooking delignification system. Background Art

[0002] With the rapid development of the domestic papermaking industry in recent years, the shortage of papermaking raw materials has become a bottleneck in the development of my country's papermaking industry. As a high-quality papermaking raw material, straw resources are valued by major papermaking companies. However, the alkaline lignin black liquor produced during traditional alkaline pulping is difficult to process, has low returns, and can even be processed at a loss. In recent years, ammonium sulfite pulping 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 produced using the ammonium sulfite process to produce high-quality pulp and fulvic acid fertilizer, achieving good economic value. However, hard straw raw materials such as cotton stalks, hemp stalks, and soybean stalks are difficult to soften and decompose during the cooking process 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 requires a long cooking cycle and high cooking temperatures and pressures, making it difficult to achieve large-scale, automated, and continuous production. Summary of the Invention

[0003] In view of this, an embodiment of the present invention provides a hard straw alkaline ammonium sulfite method rapid cooking delignification system, the main purpose of which is to quickly soften and decompose hard straw during the cooking process, creating favorable conditions for hard straw such as cotton stalks to be used as pulping and papermaking raw materials.

[0004] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0005] The embodiment of the present invention provides a hard straw alkaline ammonium sulfite method rapid cooking delignification system, the device comprising:

[0006] The pin drum meter, pre-steaming screw mechanism, screw feeder, T-tube, horizontal tube cooker, pressure grinding machine, vertical pot cooker and spray bin are connected in sequence;

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

[0008] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0009] Optionally, a first steam pipe is further included. The horizontal tube cooker includes a tube body and a spiral rod coaxially arranged in the tube body. The first steam pipe is connected to the side wall of the tube body.

[0010] Optionally, it also includes a second steam pipe. The vertical pot cooker includes a pot body, a heating pipe and a discharger. 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 tube wall of the heating pipe is evenly distributed with multiple through holes. The discharger 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 the spirally arranged blades. The side wall of the first shell is connected to the spraying bin through a feed pipe.

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

[0012] Optionally, the pressure grinding machine includes a second shell, a double-headed spiral rod and a grinding plate arranged in sequence in the second shell, the grinding plate includes a fixed plate and a movable plate, the fixed plate is fixedly installed in the second shell, and the movable plate rotates coaxially relative to the fixed plate, the inlet of the second shell is located above the double-headed spiral rod, and the outlet of the second shell is located below the movable plate, the inlet of the second shell is connected to the horizontal tube cooker through a first flexible connecting pipe, and the outlet of the second shell is connected to the vertical pot cooker through a second flexible connecting pipe.

[0013] Optionally, the screw feeder includes a third shell and a feeding screw located in the third shell, the feed port of the third shell is connected to the pre-steaming spiral mechanism, the discharge port of the third shell is connected to one side wall of the upper end of the T-shaped tube, and a cylinder is installed on the other side wall of the upper end of the T-shaped tube, and the end of the cylinder piston rod is fixedly connected to a cone, and the cone corresponds to the discharge port of the third shell;

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

[0015] Optionally, the upper end of the T-tube, the upper end of the vertical pot steamer and the upper end of the spray bin 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 is installed on the ammonium sulfite inlet pipe, and the second regulating valve is installed on the magnesium oxide inlet pipe, and the first regulating valve, the second regulating valve and the pin drum meter constitute a first interlocking control mechanism.

[0017] Optionally, it also includes a first level meter, a second level meter, a third level meter and a third regulating valve. The first level meter, the second level meter and the third level meter are installed on the upper end side of the pot body in sequence, and the third regulating valve is installed on the material delivery pipe. The first level meter, the second level meter, the third level meter 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, the first temperature transmitter and the second temperature transmitter are installed on the side wall of the pot body in sequence, and the first temperature transmitter, the second temperature transmitter and the fourth regulating valve constitute a third interlocking control mechanism.

[0019] By means of the above technical solution, the present invention has at least the following advantages:

[0020] The present device can address the unfavorable characteristics of ammonium sulfite cooking delignification of hard straws such as cotton stalks, hemp stalks, and bean stalks, such as their high density, high lignin and hemicellulose content, surface waxy layer, and complex cell wall structure. This allows the hard straw to be quickly softened and decomposed during the cooking process. The magnesium oxide solution acts as a buffer for the cooking pH, stabilizing the pH of the cooking liquor above 8 throughout the delignification stage. This allows the use of carbon steel for cooking equipment, subsequent pulp washing equipment, black liquor evaporation equipment, and pipes and fittings, significantly reducing equipment investment. The addition of magnesium also improves the quality of the fulvic acid fertilizer in the black liquor, creating favorable conditions for the high-value-added, large-scale utilization of hard straw as a raw material for pulping and papermaking. The device completes the ammonium sulfite cooking delignification process for hard straw within two hours, enabling large-scale, automated, and continuous production of hard straw cooked by the ammonium sulfite method, greatly increasing the value of the comprehensive utilization of hard straw. This opens up broad prospects for the high-value-added 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 absolute dry raw material, and the magnesium oxide is added in the form of a suspension. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic structural diagram of a hard straw alkaline ammonium sulfite rapid cooking delignification system provided in an embodiment of the present invention;

[0023] Figure 2 It is a partial cross-sectional view of a pressure grinding machine;

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

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

[0026] Figure 5 It is a structural diagram of a vertical pot steamer;

[0027] Figure 6 It is a top view of the discharger;

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

[0029] Figure 8 Schematic diagram of the structure of the horizontal tube digester.

[0030] The reference numerals in the drawings of the specification include: pin drum meter 1, pre-steaming screw mechanism 2, screw feeder 3, T-tube 4, horizontal tube cooker 5, pressure grinding machine 6, vertical pot cooker 7, spraying bin 8, ammonium sulfite inlet pipe 9, magnesium oxide inlet pipe 10, first steam pipe 11, pipe body 501, screw rod 502, second steam pipe 12, pot body 701, heating pipe 702, through hole 703, discharger 13, first shell 1301, blade 1302, hydraulic Motor 1303, temperature control liquid tank 14, temperature control pump 15, second housing 601, double-headed screw 602, fixed plate 603, movable plate 604, third housing 301, feeding screw 302, cylinder 16, cone 17, exhaust pipe 18, first regulating valve 19, second regulating valve 20, first material level meter 21, second material level meter 22, third material level meter 23, third regulating valve 24, fourth regulating valve 25, first temperature transmitter 26, second temperature transmitter 27. DETAILED DESCRIPTION

[0031] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

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

[0033] like Figure 1 As shown, one embodiment of the present invention provides a hard straw alkaline ammonium sulfite method rapid cooking delignification system, which includes:

[0034] The pin drum meter 1, pre-steaming screw mechanism 2, screw feeder 3, T-tube 4, horizontal tube digester 5, pressure grinding machine 6, vertical pot digester 7 and spray bin 8 are connected in sequence;

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

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

[0037] The present device can address the unfavorable characteristics of ammonium sulfite cooking delignification of hard straws such as cotton stalks, hemp stalks, and bean stalks, such as their high density, high lignin and hemicellulose content, surface waxy layer, and complex cell wall structure. This allows the hard straw to be quickly softened and decomposed during the cooking process. The magnesium oxide solution acts as a buffer for the cooking pH, stabilizing the pH of the cooking liquor above 8 throughout the delignification stage. This allows the use of carbon steel for cooking equipment, subsequent pulp washing equipment, black liquor evaporation equipment, and pipes and fittings, significantly reducing equipment investment. The addition of magnesium also improves the quality of the fulvic acid fertilizer in the black liquor, creating favorable conditions for the high-value-added, large-scale utilization of hard straw as a raw material for pulping and papermaking. The device completes the ammonium sulfite cooking delignification process for hard straw within two hours, enabling large-scale, automated, and continuous production of hard straw cooked by the ammonium sulfite method, greatly increasing the value of the comprehensive utilization of hard straw. This opens up broad prospects for the high-value-added 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 absolute 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, a first steam pipe 11 is further included. The horizontal tube cooker 5 includes a tube body 501 and a spiral rod 502 coaxially arranged 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 transverse tube cooker 5 is a primary cooking device, and the material to which ammonium sulfite, magnesium oxide liquid and part of the steam are added is further mixed and heated in the transverse tube cooker 5. The screw rod 502 inside the equipment is a variable diameter and variable pitch screw. The special spiral blade 1302 structure makes the volume ratio of the material in the transverse tube cooker 5 reach 70-75%, and the material can be fully mixed with the liquid and steam under the stirring action of the blade 1302, which is conducive to the uniform reaction of the material in the equipment for a longer time, so that the material can initially remove lignin and achieve a better softening effect; the material in the tube body 501 is heated to 140-150°C.

[0041] like Figure 1 、 Figure 4 、 Figure 5 、 Figure 6As shown, in a specific embodiment, it also includes a second steam pipe 12, the vertical pot cooker 7 includes a pot body 701, a heating pipe 702 and a discharger 13, the heating pipe 702 is coaxially arranged in the pot body 701, the second steam pipe 12 is connected to the upper end of the heating pipe 702, and the middle tube wall of the heating pipe 702 is evenly distributed with a plurality of through holes 703, the discharger 13 includes a first shell 1301 and a stirring shaft located in the first shell 1301, the first shell 1301 is coaxially connected to the lower end of the pot body 701, the upper end of the stirring shaft is fixedly connected to the spirally arranged blades 1302, and the side wall of the first shell 1301 is connected to the spraying bin 8 through a feed pipe.

[0042] In this embodiment, specifically, steam flows through the second steam pipe 12 and the heating pipe 702 in sequence, and is finally mixed into the material in the pot body 701 through the multiple through holes 703. The heating pipe 702 is coaxially arranged in the pot body 701 to guide the sedimentation of the material in the pot body 701.

[0043] A hydraulic motor 1303 is fixedly mounted 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 paddle. A plurality of blades 1302 are respectively fixedly connected to the paddle. The plurality of blades 1302 are arranged in a spiral shape. When the blades 1302 rotate, they drive the slurry to converge toward the center. The slurry settles evenly on the radial cross section of the first housing 1301.

[0044] Compared with the horizontal tube digester 5, the vertical boiler 7 has a larger volume and lower power, which can save energy and reduce consumption while ensuring the adequacy of the delignification reaction of the material.

[0045] The vertical boiler 7 can heat the material through the intermediate heating pipe 702 so that the material maintains a good temperature for the delignification reaction during the insulation stage;

[0046] Although the device adopts a rapid cooking delignification process, there are essential differences between ammonium sulfite pulping and alkaline and sulfate pulping. The traditional sulfite pulping heat preservation time for hard straw pulping is 4-6 hours, which can be shortened to 1.5-2 hours using the process and equipment of the device. The temperature and mixing conditions of the material coming down from the pressure grinding mill 6 are in a good state, and the material enters the rapid delignification stage. The material is kept warm in the vertical pot cooker 7 for about 1.5 hours. If the temperature drops during the heat preservation process, steam is added through the heating pipe 702 to make fine adjustments to achieve the optimal reaction conditions.

[0047] like Figure 1As shown, in a specific embodiment, it further includes a temperature control liquid tank 14 and a temperature control pump 15 , the inlet of the temperature control pump 15 is connected to the temperature control liquid tank 14 , and the outlet of the temperature control pump 15 is connected to the lower end side 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 through the temperature regulating pump 15. On the one hand, the temperature of the lower space of the vertical pot steamer 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 spraying bin 8 to achieve cold spraying.

[0049] Specifically, after the K value is qualified, a temperature regulating liquid is added to the bottom of the pot body 701 to reduce the slurry temperature to 90-95° C. to achieve cold spraying.

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

[0051] In this embodiment, specifically, the material discharged from the transverse tube cooker 5 enters the second shell 601 and reaches the rubbing plate driven by the double-headed screw rod 602. During the relative rotation of the moving plate 604 and the fixed plate 603, the material is rubbed into strips.

[0052] Specifically, the pressure grinding machine 6 is located between the horizontal tube continuous steamer and the vertical pot continuous steamer. It grinds the material that has been preliminarily delignified and fully softened by the horizontal tube digester 5 into cotton wool and silk strips, so that the structure of pectin, wax layer and part of the cell wall changes. The liquid medicine and the material are fully combined in the grinding process, creating good conditions for rapid removal of lignin; grinding after sufficient softening can greatly reduce the damage of the grinding disc to the fiber during the grinding process, and the physical properties of the fiber can be fully guaranteed.

[0053] Specifically, the pressure grinding machine 6 uses a relief type large tooth groove grinding plate structure with rubbing as the main function and grinding as the secondary function. During operation, the gap between the fixed plate 603 and the movable plate 604 is relatively large, generally 1-1.5 mm.

[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 grinding machine.

[0055] Specifically, during the grinding process of the material, the pressure grinding machine 6 converts part of the mechanical energy into heat energy, generating a certain amount of steam, which rapidly raises the material temperature to 160-165°C, reaching the optimal temperature for ammonium sulfite pulping delignification, and reducing the consumption of fresh steam.

[0056] Specifically, the inlet of the second shell 601 is connected to the horizontal tube cooker 5 through a first flexible connecting pipe, and the outlet of the second shell 601 is connected to the vertical pot cooker 7 through a second flexible connecting pipe, first eliminating the influence of the equipment vibration on the upper and lower cookers during the operation of the pressure grinding machine 6, and also compensating 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 shell 301 and a feeding screw 302 located in the third shell 301. The feed port of the third shell 301 is connected to the pre-steaming spiral mechanism 2, and the discharge port of the third shell 301 is connected to one side wall of the upper end of the T-shaped tube 4. The other side wall of the upper end of the T-shaped tube 4 is installed with a cylinder 16. The end of the piston rod of the cylinder 16 is fixedly connected to a cone 17. The cone 17 corresponds to the discharge port of the third shell 301.

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

[0059] In this embodiment, the feeding screw 302 is a variable diameter and variable pitch screw, and the third housing 301 is a tapered tube. Under the push of the feeding screw 302, the material is compressed by the variable diameter and variable pitch screw and the tapered tube. The compressed material sheets form a material plug with a dryness greater than 40%. A material plug is formed at the discharge port of the third housing 301, achieving the purpose of gas-liquid blocking and preventing backflow.

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

[0061] Specifically, the filter screen is provided on the lower side wall of the third shell 301. Under the compression of the variable diameter and variable pitch spiral and the tapered tube, the water in the material is squeezed out and discharged from the third shell 301 through the filter screen, so that the dryness of the material is greater than 40%. On this basis, the material is mixed with ammonium sulfite and magnesium oxide solution to ensure the concentration of the liquid medicine.

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

[0063] In this embodiment, specifically, the exhaust pipes 18 of the T-tube 4, the vertical pot steamer 7 and the spraying bin 8 are respectively installed with control valves. When the pressure at the top of the T-tube 4, the vertical pot steamer 7 and the spraying bin 8 is too high, the opening of each control valve can be adjusted to achieve automatic steam exhaust, so that the steam enters 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, and 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 meter 1 is a feeding metering device for qualified material sheets. The so-called qualified material sheets refer to hard straws such as cotton stalks, hemp stalks, bean stalks, etc., which have a moisture content of about 80% after crushing, screening, washing and preliminary dehydration and are suitable for entering the spiral feeder 3; the main components of the pin drum meter 1 are the outer shell and two relatively rotating drum rotors with material-feeding teeth; the upper chute of the pin drum meter 1 is in a full material state for a long time, and the rotation speed of the two rotors determines the discharge amount of the raw materials, which is a direct basis for the subsequent cooking system production capacity and the amount of liquid medicine added.

[0066] Specifically, the speed sensor of the pin drum meter 1 monitors the speed of the rotor and transmits the discharge 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 the drug solution added to the material.

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

[0068] In this embodiment, specifically, the first level meter 21, the second level meter 22 and the third level meter 23 are all tension level meters. The first level meter 21, the second level meter 22 and the third level meter 23 transmit electrical signals to the controller, and 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 meter 21 and the third level meter 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 installed in sequence 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 the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A hard straw alkaline ammonium sulfite rapid cooking delignification system, characterized in that: include: The pin drum meter, pre-steaming screw mechanism, screw feeder, T-tube, horizontal tube cooker, pressure grinding machine, vertical pot cooker and spray bin are connected in sequence; Wherein, the ammonium sulfite liquid inlet pipe and the magnesium oxide liquid inlet pipe are respectively connected to the T-shaped pipe.

2. The hard straw alkaline ammonium sulfite rapid cooking delignification system 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 arranged in the tube body. The first steam pipe is connected to the side wall of the tube body.

3. The hard straw alkaline ammonium sulfite rapid cooking delignification system according to claim 1, characterized in that: It also includes a second steam pipe. The vertical pot steamer includes a pot body, a heating pipe and a discharger. 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 tube wall of the heating pipe is evenly distributed with multiple through holes. The discharger 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 the spirally arranged blades. The side wall of the first shell is connected to the spraying bin through a feed pipe.

4. The hard straw alkaline ammonium sulfite rapid cooking delignification system according to claim 3, characterized in that: It also includes a temperature control liquid tank and a temperature control pump, wherein the inlet of the temperature control pump is connected to the temperature control liquid tank, and the outlet of the temperature control pump is connected to the lower end side of the pot body.

5. The hard straw alkaline ammonium sulfite rapid cooking delignification system according to claim 1, characterized in that: The pressure grinding machine includes a second shell, a double-headed spiral rod and a grinding plate arranged in sequence in the second shell, the grinding plate includes a fixed plate and a movable plate, the fixed plate is fixedly installed in the second shell, and the movable plate rotates coaxially relative to the fixed plate, the inlet of the second shell is located above the double-headed spiral rod, and the outlet of the second shell is located below the movable plate. The inlet of the second shell is connected to the horizontal tube steamer through a first flexible connecting pipe, and the outlet of the second shell is connected to the vertical pot steamer through a second flexible connecting pipe.

6. The hard straw alkaline ammonium sulfite rapid cooking delignification system according to claim 1, characterized in that: The screw feeder includes a third shell and a feeding screw located in the third shell, the feed port of the third shell is connected to the pre-steaming screw mechanism, the discharge port of the third shell is connected to one side wall of the upper end of the T-shaped tube, and a cylinder is installed on the other side wall of the upper end of the T-shaped tube, and the end of the cylinder piston rod is fixedly connected to a cone, and the cone corresponds to the discharge port of the third shell; The ammonium sulfite liquid inlet pipe and the magnesium oxide liquid inlet pipe are respectively connected to the upper ends of the T-shaped pipe.

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

8. The hard straw alkaline ammonium sulfite rapid cooking delignification system 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 on the ammonium sulfite inlet pipe, and the second regulating valve is installed on the magnesium oxide inlet pipe. The first regulating valve, the second regulating valve and the pin drum meter constitute a first interlocking control mechanism.

9. The hard straw alkaline ammonium sulfite rapid cooking delignification system according to claim 3, characterized in that: It also includes a first material level meter, a second material level meter, a third material level meter and a third regulating valve. The first material level meter, the second material level meter and the third material level meter are installed on the upper end side of the pot body in sequence, and the third regulating valve is installed on the material delivery pipe. The first material level meter, the second material level meter, the third material level meter and the third regulating valve constitute a second interlocking control mechanism.

10. The hard straw alkaline ammonium sulfite rapid cooking delignification system 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. The first temperature transmitter and the second temperature transmitter are installed on the side wall of the pot body in sequence. The first temperature transmitter, the second temperature transmitter and the fourth regulating valve constitute a third interlocking control mechanism.

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