System and method for co-producing high quality xylose and premium caramel color using corn cobs

Abstract

The present invention relates to a system and method for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs. The system includes a xylose production subsystem, an enzymatic hydrolysis subsystem, and a caramel color production subsystem, which are connected to each other through piping. The xylose production subsystem includes a raw material tank, a pretreatment tank, an acid hydrolysis kettle, a plate and frame filter press, a filtrate neutralization tank, a nanofiltration membrane separator, an electrodialysis separator, an evaporation concentration tank, a crystallization tank, a centrifuge, and a dryer, which are connected in sequence through piping. The enzymatic hydrolysis subsystem includes a retentate neutralization tank and an enzymatic hydrolysis reaction kettle, which are connected in sequence through piping. The caramel color production subsystem includes a sugar solution mixing tank, a browning reaction kettle, a flash tank, an ultrafiltration membrane separator, and a wiped film evaporator, which are connected in sequence through piping. The present invention not only utilizes the hexose in corn cob waste and the pentose in the xylose mother liquor as resources, but also obtains a high-value-added high-grade caramel color product, thereby improving the comprehensive utilization value of corn cobs.

Description

[Technical field]

[0001] The present invention relates to the technical field of sugar alcohol production, and more particularly to a system and method for simultaneously producing high quality xylose and premium caramel color using corn cobs. [Background technology]

[0002] Xylose is a white crystalline, sweet pentose, with a sweetness equivalent to 0.7 times that of sucrose, and is used as a substitute for sucrose to reduce the amount of sugar used and sweetness. High-quality xylose has higher purity and better light transmittance than certified xylose. High-grade caramel color is a caramel color with a color rate more than twice that of ordinary caramel color and high durability. Patent Publication No. CN111647694A describes a method for extracting xylose from corn cobs, in which corn cobs are subjected to processes such as acid hydrolysis, decolorization, ion exchange, evaporation concentration, and crystallization separation to obtain the finished xylose product. Most of the solid corn cob waste after acid hydrolysis is directly incinerated, and the xylose mother liquor after crystallization is mainly sold to syrup manufacturers at a low price, which results in a large waste of resources of hexose in corn cob waste and pentose in xylose mother liquor. Summary of the Invention [Problem to be solved by the invention]

[0003] The technical problem to be solved by the present invention is to provide a system and method for simultaneously producing high-quality xylose and high-quality caramel color using corn cobs, which uses corn cobs as raw materials to extract pentose therein, produce high-quality xylose, and produce high-quality caramel color using the pentose in the mother liquor and the hexose in the corn cob residue, thereby avoiding the waste of various sugar resources in corn cobs and converting environmentally unfriendly agricultural waste into products with high economic value, thereby promoting high-end production, environmental and ecological protection, and high-quality economic development. [Means for solving the problem]

[0004] The present invention is accomplished as follows: A system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs, comprising: The system includes a xylose production subsystem, an enzymatic hydrolysis subsystem, and a caramel color production subsystem, which are connected to each other via piping. The xylose production subsystem includes a raw material tank, a pretreatment tank, an acid hydrolysis kettle, a plate and frame filter press, a filtrate neutralization tank, a nanofiltration membrane separator, an electrodialysis separator, an evaporation concentration tank, a crystallization tank, a centrifuge, and a dryer, which are connected in series via piping. The enzymatic hydrolysis subsystem includes a retentate neutralization tank and an enzymatic hydrolysis reaction kettle, which are connected in series via piping. The caramel color production subsystem includes a sugar solution mixing tank, a browning reaction kettle, a flash tank, an ultrafiltration membrane separator, and a wiped film evaporator, which are connected in series via piping. the plate and frame filter press is provided with a filtrate outlet and a retentate outlet, the filtrate outlet is connected to a filtrate neutralization tank via a piping, the retentate outlet is connected to a feed port of the retentate neutralization tank via a piping, the centrifuge is provided with a solid outlet and a liquid outlet, the solid outlet is connected to a feed port of a dryer via a piping, the liquid outlet is connected to one feed port of a sugar solution mixing tank, and another feed port of the sugar solution mixing tank and an outlet of the enzymatic hydrolysis reaction vessel are connected to each other via a piping, the raw material tank stores the corn cob raw material to be processed, the material discharged from the outlet of the dryer is high-quality xylose, and the material finally obtained at the outlet of the wiped film evaporator is high-quality caramel color.

[0005] Furthermore, the filtrate discharged from the filtrate outlet of the plate & frame filter press is a corn cob hydrolyzate, and the residue discharged from the residue outlet of the plate & frame filter press is a corn cob waste material.

[0006] Furthermore, the liquid sent from the liquid outlet of the centrifuge is xylose mother liquor.

[0007] Furthermore, the liquid discharged from the outlet of the enzymatic hydrolysis reaction vessel is an enzymatic hydrolysis liquid.

[0008] The present invention is accomplished as follows: A method for simultaneously producing high quality xylose and high quality caramel color using corn cobs, comprising: The method uses a system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs according to any one of the above, Step 1: The corn cob powder stored in the raw material tank is sent to a pre-treatment tank through a pipe to be washed with water and pickled to obtain corn cob liquid, and then the corn cob liquid is sent to an acid hydrolysis kettle through a pipe to be hydrolyzed with acid; Step 2 of obtaining a feed liquid for the plate & frame filter press by acid hydrolysis, and sending the feed liquid for the plate & frame filter press through a pipe to the plate & frame filter press for filtering; Step 3: filtering the feed liquid to the plate and frame filter press through the plate and frame filter press to obtain a liquid portion of the corn cob hydrolyzate liquid and a solid portion of the corn cob waste, respectively; Step 4: neutralizing the corncob hydrolyzate in a filtrate neutralization tank, decolorizing in a nanofiltration membrane separator, desalination in an electrodialysis separator, concentrating in an evaporation concentration tank, crystallizing in a crystallization tank, and separating solid and liquid in a centrifuge to obtain crystalline xylose and xylose mother liquor, respectively; drying the crystalline xylose in a dryer to obtain high-quality xylose crystals with a purity of >99% and a light transmittance of >98%, and sending the xylose mother liquor to a sugar liquid mixing tank through a pipe; The method further includes step 5, in which the corn cob waste is sent to a residue neutralization tank for neutralization, then sent to an enzymatic hydrolysis reactor for enzymatic hydrolysis to obtain an enzymatic hydrolysis liquid, the enzymatic hydrolysis liquid is sent to a sugar liquid mixing tank through a pipeline for mixing with xylose mother liquor, and then browning reaction is carried out in a browning reactor, evaporation is carried out in a flash tank, separation is carried out in an ultrafiltration membrane separator, and wiped film evaporation is carried out in a wiped film evaporator to obtain a high-grade caramel color product with a color rate of 50,000 EBC. Effect of the Invention

[0009] Compared with the prior art, the system and method for simultaneously producing high-quality xylose and premium caramel color using corn cobs of the present invention has the following features:

[0010] 1. By mixing corncob waste with the pentose and hexose in xylose mother liquor to produce high-grade caramel color, the utilization rate of sugar resources in corncob can reach more than 90%. This invention not only improves the utilization rate of corncob resources, but also produces high-end caramel color products with a color rate of 50,000 EBC, greatly improving the comprehensive utilization value of corncob.

[0011] 2. Through the improvement of the entire process system and optimization of the caramel color production process, high-grade caramel color can be produced from the hexose in corncob waste and the pentose in xylose mother liquor, improving the quality of caramel, and converting 1,000 yuan / ton of xylose mother liquor and corncob waste into 5,000 yuan / ton of high-grade caramel color, increasing the economic benefit by more than five times.

[0012] 3. The incineration and large-scale accumulation of corn cob waste will occupy environmental resources and affect the construction of ecological civilization, while the comprehensive utilization of corn cob waste will contribute to sustainable development and the construction of a green ecological civilization. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of the principle of a preferred embodiment of the system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs according to the present invention. [Diagram 2] FIG. 1 is a schematic diagram of the flow direction of each material in the method for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In order to clarify the technical problems, technical solutions and advantageous effects of the present invention, the present invention will be described in more detail below with reference to examples. It should be understood that the specific examples described herein are only used to illustrate the present invention and are not intended to limit the present invention.

[0015] As shown in Figures 1 and 2, a preferred embodiment of the system for simultaneously producing high-quality xylose and premium caramel color using corn cobs of the present invention includes a xylose production subsystem I, an enzymatic hydrolysis subsystem II, and a caramel color production subsystem III, which are connected to each other through piping. The arrows in the figures indicate the flow direction of materials in the system.

[0016] The xylose production subsystem I includes a raw material tank 1, a pretreatment tank 2, an acid hydrolysis tank 3, a plate and frame filter press 4, a filtrate neutralization tank 5, a nanofiltration membrane separator 6, an electrodialysis separator 7, an evaporation concentration tank 8, a crystallization tank 9, a centrifuge 10, and a dryer 11, which are connected in series through piping. The enzymatic hydrolysis subsystem II includes a filtrate neutralization tank 12 and an enzymatic hydrolysis reaction tank 13, which are connected in series through piping. The caramel color production subsystem III includes a sugar solution mixing tank 14, a browning reaction tank 15, a flash tank 16, an ultrafiltration membrane separator 17, and a wiped film evaporator 18, which are connected in series through piping. The raw material tank 1 stores the corn cob A raw material to be processed, the material discharged from the outlet of the dryer 11 is high-quality xylose B, and the material finally obtained from the outlet of the wiped film evaporator 18 is high-quality caramel color C.

[0017] Each of the plate & frame filter presses 4 is provided with a filtrate outlet and a residue outlet, the filtrate outlet communicates with a filtrate neutralization tank 5 via piping, and the residue outlet communicates with a supply port of a residue neutralization tank 12 via piping. The filtrate discharged from the filtrate outlet of the plate & frame filter press 4 is corn cob hydrolyzate D, and the residue discharged from the residue outlet of the plate & frame filter press 4 is corn cob waste E.

[0018] The centrifuge 10 is provided with a solid outlet and a liquid outlet, the solid outlet being connected to a supply port of the dryer 11 via piping, the liquid outlet being connected to one supply port of a sugar liquid mixing tank 14, and another supply port of the sugar liquid mixing tank 14 being connected to a discharge port of the enzymatic hydrolysis reaction vessel 13 via piping.

[0019] The liquid sent from the liquid outlet of the centrifuge 10 is a xylose mother liquor F. The liquid discharged from the outlet of the enzymatic hydrolysis reaction vessel 13 is an enzymatic hydrolyzate G.

[0020] The pretreatment tank 2 is for removing impurities in the corn cob A by washing with clean water or dilute acid, the acid hydrolysis tank 3 is for hydrolyzing hemicellulose in the corn cob A, the plate and frame filter press 4 is for separating the corn cob hydrolyzate D and the corn cob waste E, and the filtrate neutralization tank 5 is for neutralizing the pH of the corn cob hydrolyzate D. The nanofiltration membrane separator 6 is for decolorizing the corn cob hydrolyzate D, and the cutoff liquid decolorized by the nanofiltration membrane separator 6 is a pigment liquid, and the permeate is a decolorized liquid. The electrodialysis membrane separator 7 is for desalting the decolorized liquid. The cutoff liquid desalted by the electrodialysis membrane separator 7 is a concentrated salt liquid, and the permeate is a desalted liquid. The evaporation concentration tank 8 and the crystallization tank 9 are for evaporation concentration and crystallization of xylose, the centrifuge 10 is for separating the crystalline xylose and the xylose mother liquor F, and the dryer 11 is for drying the high-quality xylose B crystals.

[0021] The residue neutralization tank 12 neutralizes the pH of the corn cob waste E, and the enzymatic hydrolysis reaction vessel 13 enzymatically hydrolyzes the cellulose in the corn cob waste E to produce glucose. The sugar solution mixing tank 14 mixes the xylose mother liquor F and the enzymatic hydrolysis liquid G, the browning reaction vessel 15 browns the mixed sugar solution to produce a high-grade caramel color crude product, the flash tank 16 removes amino compounds or sulfites, which are impurities in the caramel color, the ultrafiltration membrane separator 17 removes 4-methylimidazole, which is an impurity in the caramel color, and the wiped film evaporator 18 concentrates the caramel color at a low temperature to produce a high-grade caramel color C.

[0022] The present invention also discloses a method for simultaneously producing high quality xylose and high quality caramel color using corn cobs, the method using the system for simultaneously producing high quality xylose and high quality caramel color using corn cobs as described in any one of the above, the method comprising the steps of:

[0023] Step 1: The corn cob A powder stored in the raw material tank 1 is sent to the pre-treatment tank 2 via a pipe to be washed with water and pickled to obtain corn cob liquid, which is then sent to the acid hydrolysis tank 3 via a pipe for acid hydrolysis.

[0024] Step 2: The corncob liquid is acid hydrolyzed in the acid hydrolysis kettle to obtain the feed liquid H for the plate & frame filter press, and the feed liquid H for the plate & frame filter press is sent to the plate & frame filter press 4 via piping for filtration.

[0025] Step 3: The feed liquid H to the plate and frame filter press is filtered through the plate and frame filter press 4 to obtain a liquid portion and a solid portion, respectively. The liquid portion is the corncob hydrolyzate liquid D, and the solid portion is the corncob waste E.

[0026] Step 4: The corncob hydrolyzate D is neutralized in the filtrate neutralization tank 5, decolorized in the nanofiltration membrane separator 6, desalted in the electrodialysis separator 7, concentrated in the evaporation concentration tank 8, crystallized in the crystallization tank 9, and separated into solid and liquid in the centrifuge 10, to obtain crystalline xylose and xylose mother liquor, respectively. The crystalline xylose is dried in the dryer 11 to obtain high-quality xylose B crystallized finished product, and the xylose mother liquor F is sent to the sugar liquid mixing tank 14 via piping. The high-quality xylose A crystals have a purity of >99% and a light transmittance of >98%.

[0027] Step 5: The corn cob waste E is sent to the residue neutralization tank 12 for neutralization, then sent to the enzymatic hydrolysis reaction vessel 13 for enzymatic hydrolysis to obtain the enzymatic hydrolysis liquid G, which is sent to the sugar liquid mixing tank 14 via piping to be mixed with the xylose mother liquor F, and then subjected to the browning reaction in the browning reaction vessel 15, evaporation in the flash tank 16, separation in the ultrafiltration membrane separator 17, and wiped film evaporation in the wiped film evaporator 18 to obtain the high-grade caramel color C product with a high color rate of 50,000 EBC.

[0028] Specifically, in step 1, the mass percentage concentration of the sugar resource dry matter in the corn cob A is 60-70 wt%, the sugar resource dry matter contains 50-55 wt% hexose and 45-50 wt% pentose, and a 0.20-0.30 wt% sulfuric acid solution with a liquid-solid ratio of 3:1 is used for the pickling treatment.

[0029] Specifically, in step 2, in the acid hydrolysis, the corncob material / liquid ratio is 1:5, the sulfuric acid addition amount is 1.2-1.5%, the temperature is 120-125°C, and the time is 100-140min.

[0030] Specifically, in step 4, in the decolorization treatment using the nanofiltration membrane separator 6, the nanofiltration membrane separator 6 has an operating temperature of 40 to 60°C and an operating pressure of 15 to 35 bar, and in the desalination treatment using the electrodialysis separator 7, the electrodialysis membrane separator 7 has an operating current of 60 to 120 A, a voltage of 200 to 250 V, and an operating pressure of 15 to 35 bar.

[0031] Specifically, in step 5, in the enzymatic hydrolysis, the pH is adjusted to 5.5 to 6.5, 2 to 4 mass% of a commercially available cellulose complex enzyme is used as a catalyst, the temperature of the enzymatic hydrolysis reaction is controlled to 40 to 60°C, the time of the enzymatic hydrolysis reaction is 72 to 96 hours, and in the browning reaction in the browning reaction vessel 15, ammonia water or ammonium carbonate, ammonium bicarbonate and urea are mixed in a ratio of 6:2:2 to 4:4:2 as a reaction aid. In adjusting the reaction, the pH is first adjusted to 7.0 to 9.0. The temperature is then raised to 80-90°C and reacted for 30-50 minutes, then raised to 160-180°C and reacted for 3-5 hours, then the pH is adjusted to 2-4, and then the temperature is lowered to 130-150°C and reacted for 0.5-1 hour. In the separation by the ultrafiltration membrane separator 17, the ultrafiltration membrane separator 17 has an operating temperature of 40-60°C and an operating pressure of 5-7 bar, and in the wiped film evaporation by the wiped film evaporator 18, the evaporation pressure is 4-5 bar and the vacuum degree is 80-90 kpa.

[0032] The systems and methods for co-producing high quality xylose and premium caramel color using corn cobs of the present invention are further illustrated below with specific examples. Example 1

[0033] In the first embodiment of the system and method for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs of the present invention, corn cobs are used as raw materials, refined to obtain high-quality crystalline xylose, which is then enzymatically hydrolyzed, and the enzymatic hydrolysis liquid is mixed with the xylose mother liquor obtained after centrifugation to produce high-grade caramel color. The method includes the following steps:

[0034] Step 1: The corn cob powder in the raw material tank 1 is sent to the pre-treatment tank 2 through a pipe to be washed with water and pickled with acid. The pickling is carried out using a 0.20 wt% sulfuric acid solution with a liquid-solid ratio of 3:1. Then, the powder is sent to the acid hydrolysis tank 3 for hydrolysis.

[0035] Step 2: The corncob washing liquid from the pretreatment tank 2 is sent to the acid hydrolysis tank 3 via piping to be hydrolyzed at a corncob liquid-solid ratio of 5:1, sulfuric acid addition amount of 1.2%, temperature of 125°C, and time of 140 min, and then sent to the plate and frame filter press 4 for filtration.

[0036] Step 3: The hydrolysis material is separated into two parts by a plate and frame filter press 4, the liquid part is corncob hydrolyzate D, and the solid part is corncob waste E.

[0037] Step 4: The corn cob hydrolyzate D is neutralized in the filtrate neutralization tank 5, decolorized in the nanofiltration membrane separator 6, desalted in the electrodialysis separator 7, concentrated in the evaporation concentration tank 8, crystallized in the crystallization tank 9, and separated into solid and liquid by the centrifuge 10, to obtain crystalline xylose and xylose mother liquor F, respectively. The crystalline xylose is dried in the dryer 11 to obtain a high-quality xylose B crystallized finished product, and the xylose mother liquor F is sent to the sugar liquid mixing tank 14 through the piping. The high-quality xylose crystals have a purity of >99% and a light transmittance of >98%. The nanofiltration membrane separator 6 has an operating temperature of 60°C and an operating pressure of 20 bar, and the electrodialysis membrane separator 7 has an operating current of 100A, a voltage of 250V, and an operating pressure of 20 bar.

[0038] Step 5: The corn cob waste is sent to the residue neutralization tank 12 for neutralization, then sent to the enzymatic hydrolysis reaction tank 13 for enzymatic hydrolysis to obtain the enzymatic hydrolysis liquid G, which is sent to the sugar liquid mixing tank 14 through the pipe to mix with the xylose mother liquor F, and further subjected to the browning reaction in the browning reaction tank 15, evaporation in the flash tank 16, separation in the ultrafiltration membrane separator 17, and wiped film evaporation treatment in the wiped film evaporator 18 to obtain the high-grade caramel color C product with a high color rate of 50,000 EBC, other indicators all meeting the national standard, and a high utilization rate of sugar resources of 90%. In the enzymatic hydrolysis, the pH is adjusted to 5.5, 2% by mass of commercially available cellulose complex enzyme is added as a catalyst, the temperature of the enzymatic hydrolysis reaction is controlled at 50°C, and the time of the enzymatic hydrolysis reaction is 72h. In the browning reaction in the browning reaction vessel 15, a mixture of ammonium carbonate, ammonium bicarbonate and urea in a ratio of 6:2:2 is used as a reaction aid, and in adjusting the reaction, the pH is first adjusted to 9.0, then the temperature is raised to 90°C and reacted for 30 minutes, then the temperature is raised to 170°C and reacted for 3 hours, then the pH is adjusted to 3.0, then the temperature is lowered to 130°C and reacted for 1 hour. The ultrafiltration membrane separator 17 has an operating temperature of 60°C and an operating pressure of 5 bar. In the wiped film evaporation in the wiped film evaporator 18, the evaporation pressure is 4 bar and the vacuum degree is 90 kpa. Comparative Example 1

[0039] The steps of directly extracting xylose from corn cob A as raw material are specifically as follows: The corn cob raw material in the raw material tank 1 is sent to the pre-treatment tank 2 through a pipe for cleaning, then sent to the acid hydrolysis tank 3, where 1.5% sulfuric acid is added, and then the hydrolysis liquid is subjected to alkali neutralization, activated carbon decolorization, and ion exchange desalting in the plate and frame filter press 4, and then evaporated and concentrated, crystallized, and centrifuged, and finally crystalline xylose is obtained as the finished product. The corn cob waste E from the plate and frame filter press is dried and incinerated or solid waste treatment is performed, and the xylose mother liquor F after centrifugation is sold commercially for syrup production, and the actual utilization rate of sugar resources is only 30%. Comparative Example 2

[0040] The steps of directly producing caramel color using xylose mother liquor F as raw material specifically include the following: the xylose mother liquor F after centrifugation is directly sent to the browning reaction vessel 15 through a pipe, the pH is adjusted to 9.0, 10w% ammonium carbonate is added as a reaction aid, the reaction temperature is 170℃, the reaction time is 3h, and the reaction is filtered to obtain a finished caramel color with a color rate of 30,000EBC and other indicators that meet the national standards.

[0041] As described above, in the system and method of the present invention for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs, the utilization rate of the sugar resources in corn cob A is increased from 30% to 90%, and the color rate of caramel color is increased from 30,000 EBC to 50,000 EBC, improving the comprehensive utilization value of corn cobs and enhancing the product quality of caramel color.

[0042] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs, comprising: The system includes a xylose production subsystem, an enzymatic hydrolysis subsystem, and a caramel color production subsystem, which are connected to each other via piping. The xylose production subsystem includes a raw material tank, a pretreatment tank, an acid hydrolysis kettle, a plate and frame filter press, a filtrate neutralization tank, a nanofiltration membrane separator, an electrodialysis separator, an evaporation concentration tank, a crystallization tank, a centrifuge, and a dryer, which are connected in series via piping. The enzymatic hydrolysis subsystem includes a retentate neutralization tank and an enzymatic hydrolysis reaction kettle, which are connected in series via piping. The caramel color production subsystem includes a sugar solution mixing tank, a browning reaction kettle, a flash tank, an ultrafiltration membrane separator, and a wiped film evaporator, which are connected in series via piping. the plate and frame filter press is provided with a filtrate outlet and a retentate outlet, the filtrate outlet is connected to a filtrate neutralization tank via a pipe, the retentate outlet is connected to a feed port of the retentate neutralization tank via a pipe, the centrifuge is provided with a solid outlet and a liquid outlet, the solid outlet is connected to a feed port of the dryer via a pipe, the liquid outlet is connected to one feed port of a sugar solution mixing tank, and another feed port of the sugar solution mixing tank and an outlet of the enzymatic hydrolysis reaction vessel are connected to each other via a pipe, the raw material tank stores the corn cob raw material to be processed, the material discharged from the outlet of the dryer is high-quality xylose, and the material finally obtained at the outlet of the wiped film evaporator is high-quality caramel color.

2. 2. The system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs according to claim 1, characterized in that the filtrate discharged from the filtrate outlet of the plate and frame filter press is a corn cob hydrolyzate, and the residue discharged from the residue outlet of the plate and frame filter press is a corn cob waste.

3. 2. The system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs as claimed in claim 1, wherein the liquid sent from the liquid outlet of the centrifuge is xylose mother liquor.

4. The system for simultaneously producing high-quality xylose and high-grade caramel color using corn cobs as claimed in claim 1, characterized in that the liquid discharged from the outlet of the enzymatic hydrolysis reaction vessel is an enzymatic hydrolysis liquid.

5. A method for simultaneously producing high quality xylose and premium caramel color using corn cobs, comprising the steps of: A system for simultaneously producing high-quality xylose and high-grade caramel color using the corn cob according to any one of claims 1 to 4 is used, Step 1: The corn cob powder stored in the raw material tank is sent through a pipe to a pre-treatment tank for water washing and acid washing to obtain corn cob liquid, and then the corn cob liquid is sent through a pipe to an acid hydrolysis kettle for acid hydrolysis; Step 2: obtaining a feed liquid for a plate & frame filter press by acid hydrolysis, and sending the feed liquid for the plate & frame filter press through a pipe to the plate & frame filter press for filtering; Step 3: filtering the feed liquid to the plate and frame filter press through the plate and frame filter press to obtain a liquid portion of the corn cob hydrolyzate liquid and a solid portion of the corn cob waste, respectively; Step 4: neutralizing the corncob hydrolyzate in a filtrate neutralization tank, decolorizing the corncob hydrolyzate in a nanofiltration membrane separator, desalination in an electrodialysis separator, concentrating the corncob hydrolyzate in an evaporation concentration tank, crystallizing the corncob hydrolyzate in a crystallization tank, and separating the corncob hydrolyzate into solid and liquid form in a centrifuge; obtaining crystalline xylose and xylose mother liquor; drying the crystalline xylose in a dryer to obtain high-quality xylose crystals with a purity of >99% and a light transmittance of >98%; and sending the xylose mother liquor to a sugar liquid mixing tank through a pipe; and step 5. sending the corn cob waste to a residue neutralization tank for neutralization, then sending the corn cob waste to an enzymatic hydrolysis reactor for enzymatic hydrolysis to obtain an enzymatic hydrolysis liquid, sending the enzymatic hydrolysis liquid to a sugar liquid mixing tank through a pipe to mix with xylose mother liquor, and then carrying out a browning reaction in a browning reactor, evaporation in a flash tank, separation in an ultrafiltration membrane separator, and wiped film evaporation in a wiped film evaporator to obtain a high-grade caramel color product with a color ratio of 50,000 EBC.

6. The method for simultaneously producing high-quality xylose and high-grade caramel color using corn cob according to claim 5, characterized in that in step 1, the mass percentage concentration of the sugar resource dry matter in the corn cob is 60-70 wt%, the sugar resource dry matter contains 50-55 wt% hexose and 45-50 wt% pentose, and a 0.20-0.30 wt% sulfuric acid solution with a liquid-solid ratio of 3:1 is used for pickling treatment.

7. 6. The method for simultaneously producing high-quality xylose and high-grade caramel color using corn cob according to claim 5, characterized in that in step 2, in the acid hydrolysis, the material / liquid ratio of corn cob is 1:5, the amount of sulfuric acid added is 1.2-1.5%, the temperature is 120-125°C, and the time is 100-140min.

8. 6. The method for simultaneously producing high-quality xylose and high-grade caramel color using corncob according to claim 5, wherein in step 4, in the decolorization by the nanofiltration membrane separator, the nanofiltration membrane separator has an operating temperature of 40-60° C. and an operating pressure of 15-35 bar; and in the desalination by the electrodialysis separator, the electrodialysis membrane separator has an operating current of 60-120 A, a voltage of 200-250 V, and an operating pressure of 15-35 bar.

9. In step 5, in the enzymatic hydrolysis, the pH is adjusted to 5.5-6.5, 2-4% by mass of a commercially available cellulose complex enzyme is added as a catalyst, the temperature of the enzymatic hydrolysis reaction is controlled to 40-60°C, the time of the enzymatic hydrolysis reaction is 72-96h, in the browning reaction in the browning reaction vessel, ammonia water or ammonium carbonate, ammonium bicarbonate and urea are mixed in a ratio of 6:2:2 to 4:4:2 as a reaction aid, and in the reaction adjustment, the pH is first adjusted to 7.0-9.0, and then the temperature is raised to 80-90°C and the reaction is carried out for 30-50min.

6. The method for simultaneously producing high-quality xylose and high-grade caramel color using corncob according to claim 5, characterized in that: the reaction mixture is heated to 160-180°C for 3-5 h, the pH is adjusted to 2-4, and the reaction mixture is cooled to 130-150°C for 0.5-1 h; in the separation by ultrafiltration membrane separator, the ultrafiltration membrane separator has an operating temperature of 40-60°C and an operating pressure of 5-7 bar; and in the wiped film evaporation by wiped film evaporator, the evaporation pressure is 4-5 bar and the vacuum degree is 80-90 kPa.

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