Suspended stirring paddle capable of shortening hydrolysis time

Abstract

The utility model discloses a suspension type stirring paddle capable of shortening hydrolysis time, which comprises a stirring shaft, a propeller hub and blades, and the stirring shaft is connected with the propeller hub through a plurality of positioning screw holes and fixing screws; a plurality of hanging lugs are horizontally arranged on the periphery of the propeller hub along the center of a shaft hole of the stirring shaft; the hanging lug is provided with a hanging lug pin hole and is connected with the paddle through a fixing pin; each paddle comprises a groove and a blade; and groove pin holes are formed in the two ends of the groove, and the groove pin holes and the hanging lugs are connected in series through the same fixing pin. According to the utility model, the situation that the motor and the stirring paddle are damaged due to resistance such as straw stacking and winding can be effectively avoided, the manufacturing and processing precision of the stirring paddle is also easily ensured, and the stirring paddle is convenient to disassemble, assemble and transport and is very suitable for large-scale production and application.

Description

Technical Field

[0001] The utility model belongs to the technical field of functional sugar production, and in particular relates to a suspended stirring paddle capable of shortening the hydrolysis time. Background Art

[0002] In nature, xylose is widely present in the hemicellulose of plants in the form of xylan. In industry, xylose is extracted by degrading xylan. Crop straw, represented by bagasse, corn cobs, wheat straw, cottonseed hulls, rice husks, etc., is rich in xylan and is an ideal raw material for extracting xylose. The straw is sequentially subjected to acid-catalyzed hydrolysis, purification, concentration, crystallization and other processes to obtain xylose products. Among them, the hydrolysis process is the first process in xylose production and one of the key processes affecting the yield of xylose products. In addition to the type of raw materials, catalyst, reaction temperature and reaction time, stirring is also a very important factor affecting the efficiency of straw hydrolysis, because the presence or absence of stirring is directly related to the length of the reaction time. It is well known that stirring can effectively promote heat and mass transfer between materials, especially for solid-liquid-gas reaction systems, the role of stirring is particularly important, which can achieve uniform mixing of materials and achieve full reaction in a relatively short time, thereby greatly improving the reaction efficiency. The biggest difficulty in preparing xylose by straw hydrolysis at present is that straw can absorb 5-8 times of its own weight of water. The material cannot be suspended in the hydrolysis kettle and is still in a piled state. At this time, stirring the material will cause the stirring paddle to be entangled due to the accumulation of materials and the large resistance, which may damage the motor or blade. Therefore, in actual production, the straw hydrolysis reactor is not equipped with an agitator. When the straw is cooked and softened at high temperature, the volume is reduced and the liquid is leached, and the material has a certain fluidity. At this time, the material can be locally tumbled and stirred with the help of steam or compressed air. Since this stirring method has high energy consumption, it takes 2-4 hours to keep warm and hydrolyze, which is time-consuming and unevenly heated, resulting in insufficient hydrolysis. It is also easy to cause local excessive temperature, and further degradation of xylose produces furfural, organic acid, pigment, etc., thereby affecting the quality of the hydrolyzate and the yield of xylose. In addition, due to insufficient hydrolysis, the hydrolysis residue fiber still remains in a long state, which is easy to cause the reactor spray outlet to be blocked and the slag discharge to be unsmooth, which seriously affects the progress of the next cycle of hydrolysis. Invention patents CN114214468A and CN105713998A both disclose a xylose production process, and the processes of the two are similar in the hydrolysis process, both use corn cobs as raw materials, and then carry out acid-catalyzed hydrolysis after crushing, cooking, etc. Although a stirring device is used for stirring during the hydrolysis process, it still takes 2-4 hours of heat preservation for hydrolysis, which is equivalent to the effect of using steam and compressed air in actual production. It can be seen that the stirring effect of the two technologies is not obvious. Utility Model Content

[0003] The utility model aims to provide a suspended stirring paddle capable of shortening the hydrolysis time in view of the deficiencies in the prior art, which can effectively promote uniform mixing of straws, shorten the reaction time and improve the hydrolysis efficiency.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A suspended stirring paddle capable of shortening the hydrolysis time comprises a stirring shaft, a hub and a blade, wherein the stirring shaft is connected to the hub via a plurality of positioning screw holes and fixing screws; a plurality of hanging ears are horizontally arranged on the outer circumference of the hub along the center of the shaft hole of the stirring shaft; the hanging ears are provided with hanging ear pin holes and are connected to the blade via fixing pins; the blade comprises a groove and a blade; the hanging ears are embedded in the groove, and groove pin holes are provided at both ends, which are connected in series with the hanging ears via the same fixing pin.

[0006] Furthermore, the hanging ears are evenly distributed on the outer circumference of the hub by welding.

[0007] Furthermore, the number of the hanging ears is 4-6.

[0008] Furthermore, the ratio of the blade length to the reactor diameter is 0.3-0.7.

[0009] Furthermore, the number of the blades is the same as the number of the hanging ears.

[0010] Furthermore, the blade is wedge-shaped.

[0011] Furthermore, the inclination angle of the blade is 0-10°.

[0012] Furthermore, the horizontal width of the blade is the distance between the intersection points of the extended lines of the centers of the pin holes of two adjacent grooves.

[0013] Compared with the prior art, the advantages of the utility model are as follows:

[0014] 1. The utility model can effectively avoid the damage of the motor and the stirring paddle caused by resistance such as straw accumulation and entanglement, and the manufacturing and processing accuracy of the stirring paddle is also easy to ensure, and it is convenient for disassembly, assembly and transportation, which is very suitable for large-scale production applications.

[0015] 2. At present, the straw hydrolysis reactor is not equipped with a stirring paddle, and the materials in the reactor are heated unevenly. In order to achieve a higher degree of hydrolysis, the insulation time must be extended, usually 90-120 minutes. The use of the suspended stirring paddle of the utility model can effectively enhance the solid-liquid-gas mass transfer and mixing. The straw hydrolysis insulation time only needs 30-60 minutes to reach or even exceed the existing technical level, greatly improving the straw hydrolysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the front view of the propeller hub;

[0017] Figure 2 It is a top view of the propeller hub;

[0018] Figure 3 It is the front view of the propeller blade;

[0019] Figure 4 It is a top view of the propeller blade;

[0020] Figure 5 This is a front view of the suspended stirring paddle in a stationary state;

[0021] Figure 6 This is a top view of the suspended stirring paddle in a stationary state;

[0022] Figure 7 It is a top view of the motion state of the suspended stirring paddle.

[0023] In the attached figure:

[0024] 1. Hub; 2. Positioning screw hole; 3. Hanging ear pin hole; 4. Shaft hole; 5. Hanging ear; 6. Groove pin hole; 7. Groove; 8. Blade; 9. Paddle blade; 10. Agitator shaft; 11. Fixing screw; 12. Fixing pin. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to common technical knowledge and conventional means in the field, which should all be included in the protection scope of the present invention.

[0026] A method for improving the hydrolysis efficiency of preparing xylose from straw comprises the following steps:

[0027] 1) Loading. Add straw raw materials into the hydrolysis kettle according to the loading coefficient of 0.6-0.85, and then pump in a dilute acid solution with a concentration of 0.5-1.5% (w / w), and seal the hydrolysis kettle. The mass ratio of the dry weight of the straw raw materials to the dilute acid solution is 1:5-1:12.

[0028] 2) Hydrolysis. Steam is introduced into the hydrolysis kettle, and the suspended stirring blade is started. The speed of the suspended stirring blade is adjusted to 10-150 rpm. After the temperature in the kettle rises to the set temperature of 100-135°C, it is kept warm for 30-60 minutes. After the hydrolysis is completed, it is sprayed into the slurry tank, and then the slurry is separated to obtain xylose hydrolyzate and hydrolysis residue.

[0029] The straw raw material includes one or more of bagasse, sugarcane pith, wheat straw, forage grass, cottonseed husk, rice straw, rice husk and corn cob.

[0030] The shape of the suspended stirring paddle can be changed according to the state of the material, including before starting, the blades of the suspended stirring paddle are in a closed clamped state, vertically parallel to the axis; after starting, as the temperature rises, the straw in the kettle gradually softens, the acid adsorbed by the straw gradually leaches out, the buoyancy increases, the friction with the straw weakens, the resistance decreases, and the suspended stirring paddle gradually opens from vertical to horizontal and is suspended in the system. Due to sufficient stirring during the process, the material in the kettle is evenly heated, fully hydrolyzed, and the hydrolysis time is shortened, thereby achieving the purpose of improving the hydrolysis efficiency.

[0031] The suspended stirring paddle of the utility model is as follows Figure 1-Figure 7 , including a stirring shaft 10, a hub 1 and a blade 9, wherein the stirring shaft 10 is connected to the hub 1 through a plurality of positioning screw holes 2 and fixing screws 11; a plurality of hanging ears 5 are horizontally arranged on the outer periphery of the hub 1 along the center of the stirring shaft shaft hole 4; the hanging ear 5 has a hanging ear pin hole 3 and is connected to the blade 9 through a fixing pin 12; the blade 9 includes a groove 7 and a blade 8; the hanging ear 5 is embedded in the groove 7, and groove pin holes 6 are arranged at both ends, which are connected in series with the hanging ear 5 through the same fixing pin 12.

[0032] The number of the hanging ears 5 is 4-6, and they are evenly distributed on the periphery of the hub 1 by welding.

[0033] The ratio of the length of the blades 9 to the diameter of the reactor is 0.3-0.7, and the number of the blades 9 is the same as that of the hanging ears 5.

[0034] The blade 8 is wedge-shaped, with an inclined surface angle of 0-10°, and a horizontal width of the blade 8 is the distance between the intersection points of the extended center lines of two adjacent groove pin holes 6 .

[0035] In order to make the present invention more fully disclosed, the following is explained through more specific embodiments based on the above description.

[0036] Example 1

[0037] This embodiment uses 4 suspended agitator blades, the ratio of blade length to hydrolysis kettle diameter is 0.7, and the blade slope angle is 6°. 150 kg of wheat straw is put into the hydrolysis kettle, and dilute hydrochloric acid solution is pumped in at a ratio of wheat straw dry weight to hydrochloric acid solution mass of 1:12 and a system hydrochloric acid concentration of 1.5% (w / w). The suspended agitator is started, and the temperature begins to rise. The hydrolysis is carried out at 100°C for a certain period of time. After the hydrolysis is completed, it is sprayed into the slurry tank, and the slag and liquid are separated to obtain wheat straw hydrolyzate and residue respectively. The xylose extraction rate in the hydrolyzate is used as an evaluation method for improving the efficiency of straw hydrolysis by the suspended agitator of the present invention (the same below), and the implementation conditions and results are shown in Table 1. Among them, the xylose extraction rate is calculated using the following formula:

[0038]

[0039] In the formula: Y is the xylose extraction rate (on the basis of raw material dry matter) %; V is the volume of hydrolysate, L; C is the mass concentration of xylose in the hydrolysate, g / L; m is the mass of raw material, g; X is the moisture content of raw material, %.

[0040] Table 1 Implementation conditions and results

[0041]

[0042] The implementation results in Table 1 show that under the same hydrolysis conditions, the xylose extraction rate in wheat straw reaches a maximum of 8.44% after 90 minutes of non-stirring hydrolysis; and the xylose extraction rate in wheat straw basically reaches the above-mentioned non-stirring technical level by adopting a method for improving the hydrolysis efficiency of preparing xylose from straw and a suspended stirring paddle disclosed in the present invention, and keeping warm at 70rpm for 45min; increasing the stirring speed can effectively promote sufficient hydrolysis, stirring at 110rpm for 45min, or stirring at 150rpm for 30min, the xylose extraction rate in wheat straw exceeds the above-mentioned non-stirring technical level, and extending the insulation time, the xylose extraction rate shows a downward trend, which may be caused by the further degradation of xylose at high temperature. In summary, the optimal conditions of this embodiment are a stirring speed of 150rpm and a insulation time of 30min, which greatly improves the hydrolysis efficiency of wheat straw, reaching 8.71%, and the wheat straw fiber is broken into a paste, and all materials are discharged smoothly after the reaction is completed.

[0043] Example 2

[0044] In this embodiment, the number of suspended stirring blades is 6, the ratio of blade length to reactor diameter is 0.5, and the blade inclined angle is 10°. 2000 kg of sugarcane pith is put into the hydrolysis reactor, and dilute hydrochloric acid solution is pumped in at a ratio of 1:6 of dry weight of sugarcane pith to hydrochloric acid solution and a system hydrochloric acid concentration of 0.8% (w / w), the suspended stirring blade is started, the temperature is raised, and the hydrolysis is carried out at 115°C for a certain period of time. After the hydrolysis is completed, it is sprayed into the slurry tank, and the slag and liquid are separated to obtain sugarcane pith hydrolyzate and residue respectively. The implementation conditions and results are shown in Table 2.

[0045] Table 2 Implementation conditions and results

[0046]

[0047]

[0048] The implementation results in Table 2 show that under the same hydrolysis conditions, the non-stirring hydrolysis was kept warm for 120 minutes, and the xylose extraction rate in the sugarcane pith reached a maximum of 12.45%; while the method for improving the hydrolysis efficiency of preparing xylose from straw and the suspended stirring paddle disclosed in the present invention were used, and the xylose extraction rate in the sugarcane pith was kept warm for 45 minutes at 60 rpm, and the xylose extraction rate in the sugarcane pith was higher than the above-mentioned non-stirring technical level; the xylose extraction rate in the sugarcane pith was kept warm for 60 minutes at 60 rpm or 45 minutes at 80 rpm, and the xylose extraction rate in the sugarcane pith exceeded the above-mentioned non-stirring technical level; the effect of increasing the stirring speed to 100 rpm was not obvious. In summary, the optimal conditions of this embodiment are a stirring speed of 60 rpm and a holding time of 60 minutes, which greatly improves the hydrolysis efficiency of the sugarcane pith, reaching 12.73%, and the sugarcane pith fibers are sheared into powder, and all materials are discharged smoothly after the reaction is completed.

[0049] Example 3

[0050] In this embodiment, the number of suspended stirring blades is 5, the ratio of blade length to hydrolysis kettle diameter is 0.3, and the blade slope angle is 10°. 3000 kg of forage grass is put into the hydrolysis kettle, and dilute hydrochloric acid solution is pumped into the hydrolysis kettle at a ratio of 1:5 of dry weight of forage grass to hydrochloric acid solution and a system hydrochloric acid concentration of 1.0% (w / w). The suspended stirring blade is started, and the temperature is raised. The hydrolysis is carried out at 135°C for a certain period of time. After the hydrolysis is completed, it is sprayed into the slurry tank, and the slag and liquid are separated to obtain the forage grass hydrolyzate and the residue respectively. The implementation conditions and results are shown in Table 3.

[0051] Table 3 Implementation conditions and results

[0052]

[0053]

[0054] The implementation results in Table 3 show that under the same hydrolysis conditions, the non-stirring hydrolysis was kept warm for 120 minutes, and the xylose extraction rate in the forage grass reached a maximum of 6.94%; while the method for improving the hydrolysis efficiency of preparing xylose from straw and the suspended stirring paddle disclosed in the present invention were used, and the xylose extraction rate in the forage grass could reach the above-mentioned non-stirring technical level by keeping warm at 30rpm for 75min and at 70rpm for 30min; the xylose extraction rate in the forage grass exceeded the above-mentioned non-stirring technical level by keeping warm at 50rpm and 70rpm for 45min; and the effect of improving the xylose extraction rate by continuing to increase the stirring speed to 90rpm was not obvious. In summary, the optimal conditions of this embodiment are a stirring speed of 50rpm and a holding time of 45min, which greatly improves the forage grass hydrolysis efficiency to 7.18%, and the forage grass fiber is sheared into fine and short particles, and all materials are discharged smoothly after the reaction is completed.

Claims

1. A suspended stirring blade capable of shortening the hydrolysis time, characterized in that: The invention comprises a stirring shaft (10), a hub (1) and a blade (9); the stirring shaft (10) is connected to the hub (1) via a plurality of positioning screw holes (2) and fixing screws (11); a plurality of hanging ears (5) are horizontally arranged on the outer periphery of the hub (1) along the center of the stirring shaft axial hole (4); the hanging ears (5) are provided with hanging ear pin holes (3) and are connected to the blade (9) via fixing pins (12); the blade (9) comprises a groove (7) and a blade (8); the hanging ears (5) are embedded in the groove (7), and groove pin holes (6) are provided at both ends, which are connected in series with the hanging ears (5) via the same fixing pin (12).

2. The suspended stirring blade capable of shortening the hydrolysis time according to claim 1, characterized in that: The hanging ears (5) are evenly distributed on the outer circumference of the hub (1) by welding.

3. The suspended stirring blade capable of shortening the hydrolysis time according to claim 2, characterized in that: The number of the hanging ears (5) is 4-6.

4. The suspended stirring blade capable of shortening the hydrolysis time according to claim 1, characterized in that: The ratio of the length of the blade (9) to the diameter of the reactor is 0.3-0.

7.

5. The suspended stirring blade capable of shortening the hydrolysis time according to claim 4, characterized in that: The number of the blades (9) is the same as the number of the hanging ears (5).

6. The suspended stirring blade capable of shortening the hydrolysis time according to claim 1, characterized in that: The blade (8) is wedge-shaped.

7. The suspended stirring blade capable of shortening the hydrolysis time according to claim 6, characterized in that: The inclined surface angle of the blade (8) is 0-10°.

8. The suspended stirring blade capable of shortening the hydrolysis time according to claim 7, characterized in that: The horizontal width of the blade (8) is the distance between the intersection points of the extended center lines of two adjacent groove pin holes (6).

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