A synergistic dechlorination and quality improvement process for printing and dyeing sludge using traditional Chinese medicine residues

Abstract

The invention discloses a synergistic dechlorination and quality improvement process for printing and dyeing sludge using traditional Chinese medicine residues, comprising the following steps: crushing discarded traditional Chinese medicine residues; placing the crushed discarded traditional Chinese medicine residues in an enzymatic hydrolysis solution for enzymatic hydrolysis to decompose the cross-linked structure of the lignin component, and then filtering to obtain the enzymatic hydrolysis traditional Chinese medicine residues; mixing the enzymatic hydrolysis traditional Chinese medicine residues with printing and dyeing sludge; adjusting the moisture content of the mixture of the enzymatic hydrolysis traditional Chinese medicine residues and the printing and dyeing sludge, and stirring to form a slurry; then adding a hydrothermal additive to the slurry, mixing to obtain a mixed slurry; performing a hydrothermal carbonization reaction on the mixed slurry; and performing solid-liquid separation after the reaction to obtain a solid phase and a liquid phase. The process fully utilizes the interaction between the discarded traditional Chinese medicine residues and the printing and dyeing sludge components in the hydrothermal process to promote dechlorination and product quality improvement, remove chlorine elements in the printing and dyeing sludge, and promote the improvement of the calorific value of hydrothermal carbon, thereby effectively reducing the environmental risks and operating costs of subsequent incineration of the printing and dyeing sludge.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental engineering and solid waste resource utilization, and is a process for collaboratively dechlorinating and improving the quality of printing and dyeing sludge by utilizing traditional Chinese medicine residues. Background Art

[0002] Printing and dyeing sludge is an unavoidable byproduct of the textile industry, and improper disposal can easily cause environmental pollution. Currently, incineration is the primary disposal method for printing and dyeing sludge, but this is limited by the characteristics of the raw material: on the one hand, the high chlorine content of printing and dyeing sludge makes it prone to dioxin production after incineration, making incineration exhaust gas treatment difficult; on the other hand, the low calorific value of printing and dyeing sludge requires the addition of auxiliary fuel during its incineration, resulting in increased operating costs. Therefore, effective technologies are urgently needed to dechlorinate and upgrade printing and dyeing sludge. my country has significant industrial advantages in the production and processing of raw materials for pharmaceuticals, which produces a large amount of waste traditional Chinese medicine residue. Waste traditional Chinese medicine residue is rich in lignin, and previous studies have shown that lignin can promote material dechlorination under hydrothermal conditions. Based on this background, this process proposes to dechlorinate and upgrade printing and dyeing sludge by mixing traditional Chinese medicine residue with printing and dyeing sludge through hydrothermal carbonization, and combines mechanical crushing and rapid enzymatic pretreatment to improve process efficiency.

[0003] This process has significant cost advantages over existing technologies, which are reflected in two aspects: (1) Low operating costs: The process is based on the idea of ​​"treating waste with waste" and does not involve other additives except KOH / NaOH, so the process does not require additional reagent costs. Secondly, although the process involves a hydrothermal carbonization process that requires heating to 180°C, it has advantages over existing processes. For example, the existing technology "Dechlorination Method for Fly Ash from Incineration of Domestic Waste" (Publication No.: CN115138022A) requires continuous calcination at 1000-1200°C; (2) Low investment in fixed equipment: This process does not involve non-standard customized equipment, and all process environments are based on conventional chemical structures. Therefore, the process has the advantage of low equipment investment. Existing dechlorination technologies often involve investment in non-standard equipment. For example, the existing technologies "A Hydrogenation Dechlorination Treatment Device for Chlorinated Wastewater" (Publication No.: CN221319392U), "A Waste Plastic Pyrolysis Dechlorination Device" (Publication No.: CN221344447U), "A Venturi-type Carbon Dioxide Assisted Fly Ash Dechlorination Device" (Publication No.: CN220862327U), and "A Carbon Dioxide Assisted Three-stage Countercurrent Water Washing Fly Ash Dechlorination Device and Method" (Publication No.: CN115193863A) all involve investment in related equipment. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention proposes a synergistic dechlorination and quality improvement process for printing and dyeing sludge using traditional Chinese medicine residue. The purpose of the present invention can be achieved through the following technical solutions:

[0005] A dechlorination and synergistic quality improvement process for printing and dyeing sludge using traditional Chinese medicine residues is characterized in that the process flow specifically includes the following steps:

[0006] Step 1 Mechanical crushing: crush the discarded Chinese medicine residue to a particle size of ≤30mm;

[0007] Step 2: Rapid enzymatic hydrolysis: placing the crushed Chinese medicinal residues described in step 1 in an enzymatic hydrolysis solution for rapid enzymatic hydrolysis, thereby preliminarily decomposing the cross-linked structure of the lignin components, and then filtering to obtain the enzymatic hydrolyzed Chinese medicinal residues;

[0008] Step 3: mixing materials: mixing the enzymatic hydrolysis Chinese medicinal residues and printing and dyeing sludge described in step 2;

[0009] Step 4: Slurry adjustment and drug preparation: the moisture content of the mixture of the Chinese medicinal residue and the printing and dyeing sludge in step 3 is adjusted to 90%, and the mixture is stirred to form a slurry; then, a hydrothermal additive is added to the slurry and mixed evenly;

[0010] Step 5: Hydrothermal carbonization: The slurry mixed in step 4 is transferred into a reactor for hydrothermal carbonization reaction;

[0011] Step 6: Solid-liquid separation: After the reaction is completed, the reactor is opened to perform solid-liquid separation to obtain hydrothermal charcoal (solid phase) and chlorine-containing water phase (liquid phase).

[0012] Preferably, the water content of the discarded Chinese medicinal residues and the printing and dyeing sludge is 75% to 85% (based on wet weight).

[0013] Preferably, in step 1, after completing a single crushing stage, the crushing should be checked, and materials that do not meet the particle size requirements (particle size ≥ 30 mm) should be returned to step 1 for crushing again.

[0014] Preferably, the enzymatic hydrolysis solution in step 2 is a laccase solution, and its activity unit concentration needs to be 0.3u / mL to 0.5u / mL. When preparing the enzymatic hydrolysis solution, the laccase is dissolved in an acetate buffer solution with a pH between 4.5 and 5.5.

[0015] Preferably, the rapid enzymatic hydrolysis process in step 2 is 1 hour, and the enzymatic hydrolysis solution is added to the discarded traditional Chinese medicine residue at a liquid-to-solid ratio of 5: 1. The enzymatic hydrolysis process is maintained at 25° C. and continuously stirred.

[0016] Preferably, the weight ratio of the enzymatically hydrolyzed Chinese medicinal residue to the printing and dyeing sludge in step 3 should be 1:2 to 1:1.

[0017] Preferably, in step 4, the moisture content of the mixture is adjusted by adding supplemental water, which comprises distilled water and the hydrothermal carbonization aqueous phase product. Distilled water is added only when the aqueous phase product is insufficient. The hydrothermal additive can be either KOH or NaOH, added in solid form, in an amount of 5% by mass of the slurry.

[0018] Preferably, in step 5, the hydrothermal carbonization is carried out in a sequencing batch reactor at a reaction temperature of 180° C. for 2 hours, and the reaction pressure is the autogenous pressure generated by the slurry as the reaction temperature increases.

[0019] Preferably, in step 6, solid-liquid phase separation is achieved by vacuum filtration. The solid phase after separation is hydrothermal charcoal, which has a high calorific value and can be subsequently incinerated. The liquid phase is the aqueous product. When the chlorine content of the aqueous product is greater than 1000 mg / L, it is discharged as a high-concentration chlorine solution. When the chlorine content of the aqueous product is ≤1000 mg / L, it is returned to step 4 as make-up water for slurry preparation.

[0020] Beneficial effects of the present invention:

[0021] This method simultaneously dechlorinates and increases the calorific value of printing and dyeing sludge, thereby eliminating the environmental risks and additional fuel requirements associated with subsequent incineration. The process is simple, gentle, requires few and inexpensive additives, requires no investment in non-standard equipment, and uses low-value waste as raw materials. This makes the process significantly low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Comparative Example 1

[0026] Taking the printing and dyeing sludge from a printing and dyeing wastewater treatment plant A as the implementation object, its chlorine content was measured to be 1.455 mg / g and its high calorific value was 6.08 MJ / kg.

[0027] Example 1

[0028] (1) This process is used to dechlorinate and improve the quality of the product. The weight ratio of the enzymatic hydrolyzed Chinese medicine residue to the printing and dyeing sludge should be 1:1, and the unit concentration of the enzymatic hydrolyzate activity should be 0.3u / mL.

[0029] (2) Dechlorination rate (DE) is calculated based on the following formula:

[0030]

[0031] Where C0 and C e Represent the chlorine content (mg / g) in printing and dyeing sludge and hydrothermal charcoal, respectively.

[0032] Table 1 Dechlorination and quality improvement effect of Example 1

[0033]

[0034] In this embodiment, after being treated by this process, the dechlorination rate of the printing and dyeing sludge reaches 64.93%, and the calorific value is increased by 73.68%.

[0035] Comparative Example 2

[0036] Taking the printing and dyeing sludge from a printing and dyeing wastewater treatment plant B as the implementation object, its chlorine content was measured to be 3.227 mg / g and its high calorific value was 8.11 MJ / kg.

[0037] Example 2

[0038] (1) This process is used to dechlorinate and improve the quality of the product. The weight ratio of the enzymatic hydrolyzed Chinese medicine residue to the printing and dyeing sludge should be 1:1, and the unit concentration of the enzymatic hydrolyzate activity should be 0.3u / mL.

[0039] (2) Dechlorination rate (DE) is calculated based on the following formula:

[0040]

[0041] Where C0 and C e Represent the chlorine content (mg / g) in printing and dyeing sludge and hydrothermal charcoal, respectively.

[0042] Table 2 Dechlorination and quality improvement effects of Example 2

[0043]

[0044] In this embodiment, after being treated by this process, the dechlorination rate of the printing and dyeing sludge reaches 66.50%, and the calorific value is increased by 61.04%.

[0045] Comparative Example 3

[0046] Taking the printing and dyeing sludge from a printing and dyeing wastewater treatment plant A as the implementation object, its chlorine content was measured to be 1.455 mg / g and its high calorific value was 6.08 MJ / kg.

[0047] Example 3

[0048] (1) This process is used to dechlorinate and improve the quality of the product. The weight ratio of the enzymatic hydrolyzed Chinese medicine residue to the printing and dyeing sludge should be 1:1, and the unit concentration of the enzymatic hydrolyzate activity should be 0.5u / mL.

[0049] (2) Dechlorination rate (DE) is calculated based on the following formula:

[0050]

[0051] Where C0 and C e Represent the chlorine content (mg / g) in printing and dyeing sludge and hydrothermal charcoal, respectively.

[0052] Table 3 Dechlorination and quality improvement effects of Example 3

[0053]

[0054] In this embodiment, after being treated by this process, the dechlorination rate of the printing and dyeing sludge reaches 65.77%, and the calorific value is increased by 81.09%.

[0055] Comparative Example 4

[0056] Taking the printing and dyeing sludge from a printing and dyeing wastewater treatment plant A as the implementation object, its chlorine content was measured to be 1.455 mg / g and its high calorific value was 6.08 MJ / kg.

[0057] Example 4

[0058] (1) This process is used to dechlorinate and improve the quality of the product. The weight ratio of the enzymatic hydrolyzed Chinese medicine residue to the printing and dyeing sludge should be 1:2, and the unit concentration of the enzymatic hydrolyzate activity should be 0.5u / mL.

[0059] (2) Dechlorination rate (DE) is calculated based on the following formula:

[0060]

[0061] Where C0 and C e Represent the chlorine content (mg / g) in printing and dyeing sludge and hydrothermal charcoal, respectively.

[0062] Table 4 Dechlorination and quality improvement effect of Example 4

[0063]

[0064]

[0065] In this embodiment, after being treated by this process, the dechlorination rate of the printing and dyeing sludge reaches 50.86%, and the calorific value is increased by 61.35%.

[0066] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0067] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A synergistic dechlorination and quality improvement process for printing and dyeing sludge using traditional Chinese medicine residues, characterized in that: The following steps are involved: Crushing the discarded Chinese medicine residue; The crushed discarded Chinese medicine residue is placed in an enzymatic hydrolysis solution for enzymatic hydrolysis to decompose the cross-linked structure of the lignin component, and then filtered to obtain the enzymatic hydrolyzed Chinese medicine residue, wherein the activity unit concentration of the enzymatic hydrolysis solution is 0.3U / mL to 0.5U / mL; Mixing the above enzymatically hydrolyzed Chinese medicinal residue with printing and dyeing sludge, wherein the weight ratio of the enzymatically hydrolyzed Chinese medicinal residue to the printing and dyeing sludge is 1:2 to 1:1; Adjusting the moisture content of the mixture of the enzymatically hydrolyzed Chinese medicinal residue and the printing and dyeing sludge, and stirring to form a slurry; then adding a hydrothermal additive to the slurry, and mixing to obtain a mixed slurry; subjecting the mixed slurry to a hydrothermal carbonization reaction; After the reaction is completed, solid-liquid separation is performed to obtain hydrothermal charcoal and chlorine-containing water phase.

2. The process according to claim 1, characterized in that The water content of the discarded traditional Chinese medicine residue and the printing and dyeing sludge is 75% to 85%.

3. The process according to claim 1, characterized in that The enzymatic hydrolysis solution includes a laccase solution.

4. The process according to claim 1, characterized in that The solid-liquid ratio of the enzymatic hydrolysis solution to the discarded traditional Chinese medicine residue is 5:1; the enzymatic hydrolysis time is 1 hour, and the enzymatic hydrolysis temperature is 25°C.

5. The process according to claim 1, characterized in that The discarded traditional Chinese medicine residues include lignin.

6. The process according to claim 1, characterized in that The temperature of the hydrothermal carbonization reaction is 180° C., and the reaction time is 2 h.

7. The process according to claim 1, characterized in that The hydrothermal additive includes one or more of KOH and NaOH.

8. Use of the process according to any one of claims 1 to 7 in the dechlorination and upgrading of printing and dyeing sludge.

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