CN111484569A - Zero-emission treatment method of viscose squeezed alkali liquor - Google Patents
Zero-emission treatment method of viscose squeezed alkali liquor Download PDFInfo
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- CN111484569A CN111484569A CN202010477696.2A CN202010477696A CN111484569A CN 111484569 A CN111484569 A CN 111484569A CN 202010477696 A CN202010477696 A CN 202010477696A CN 111484569 A CN111484569 A CN 111484569A
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
- C08B37/0003—General processes for their isolation or fractionation, e.g. purification or extraction from biomass
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
- C01D1/04—Hydroxides
- C01D1/28—Purification; Separation
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
- C01D5/16—Purification
Abstract
The invention relates to the technical field of viscose squeezed alkali liquor treatment, in particular to a zero-emission treatment method of viscose squeezed alkali liquor. The invention provides a method for recovering hemicellulose, alkali and water from viscose squeezed alkali liquor and also obtains a byproduct sodium sulfate, thereby realizing zero emission of the whole treatment method, compared with the prior nanofiltration technology for recovering alkali, the method can recover the alkali and the water recovered from the viscose squeezed alkali liquor to be reused in different procedures of viscose production, and simultaneously, the hemicellulose in the viscose squeezed alkali liquor can be completely recovered, and the alkali recovery rate can reach more than 90%.
Description
Technical Field
The invention relates to the technical field of treatment of viscose squeezed alkali liquor, and discloses a zero-emission treatment method of viscose squeezed alkali liquor.
Background
The main components in the viscose squeezed alkali liquor are sodium hydroxide and hemicellulose, the existing alkali squeezed liquid treatment method mostly adopts a nanofiltration technology to separate the hemicellulose from the viscose squeezed alkali liquor to obtain relatively pure alkali liquor, the purified alkali liquor can be directly reused in the process, but the nanofiltration membrane of the nanofiltration technology can only recycle part of alkali, the hemicellulose in trapped liquid obtained after the viscose squeezed alkali liquor is separated through the nanofiltration membrane is concentrated, the concentrated liquid still contains a large amount of alkali, the part of feed liquid is used as waste alkali for neutralization, the hemicellulose enters waste water treatment, or caustic soda is recovered by burning, and the hemicellulose is combusted. At present, it is also reported that hemicellulose powder containing a large amount of sodium sulfate is obtained by directly performing spray drying after a hemicellulose concentrated solution obtained by separating viscose squeezed alkali liquor through a nanofiltration membrane is neutralized, and the hemicellulose powder cannot be effectively utilized due to the fact that the hemicellulose powder contains a large amount of sodium sulfate. Therefore, the hemicellulose in the prior art is not fully recycled.
Disclosure of Invention
The invention provides a zero-emission treatment method of viscose squeezed alkali liquor, which overcomes the defects of the prior art and can effectively realize zero emission of the viscose squeezed alkali liquor.
The technical scheme of the invention is realized by the following measures: a zero-emission treatment method of viscose squeezed alkali liquor is carried out according to the following method: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor; secondly, separating the pretreated viscose squeezed alkali liquor by a primary membrane to obtain a primary concentrated solution and a primary filtrate respectively, wherein the primary filtrate is purified alkali liquor and can be directly recycled; a third step; adding water into the primary concentrated solution for dialysis, and separating by a secondary membrane to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the secondary filtrate is purified alkali liquor and can be directly recycled; fourthly, adding sulfuric acid into the secondary concentrated solution, adjusting the pH value to 5-7 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, adding water into the third-stage concentrated solution for washing, and performing spray drying to obtain hemicellulose powder; fifthly, separating the third-stage filtrate by a fourth-stage membrane to obtain a fourth-stage concentrated solution and a fourth-stage filtrate respectively, wherein the fourth-stage filtrate is water and can be directly recycled; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
The following is further optimization or/and improvement of the technical scheme of the invention:
in the second step, a nanofiltration membrane is adopted for primary membrane separation, the rejection rate of the primary membrane to sodium chloride is 60-90%, the primary membrane separation temperature is 10-80 ℃, and the pressure is 1-5 MPa.
In the third step, the secondary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the interception molecular weight of the secondary membrane separation is 200-5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1-6 m/s, the secondary membrane separation temperature is 10-80 ℃, and the pressure is 0.1-4 MPa.
In the fourth step, one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane is adopted for three-stage membrane separation, the cutoff molecular weight of the three-stage membrane separation is 200-100000, the three-stage membrane separation mode is cross flow filtration, the membrane surface filtration flow rate is 1-6 m/s, the three-stage membrane separation temperature is 10-80 ℃, and the pressure is 0.1-4 MPa.
In the fifth step, one of a nanofiltration membrane and a reverse osmosis membrane is adopted for the four-stage membrane separation, the rejection rate of the four-stage membrane to sodium chloride is 95-100%, the temperature of the four-stage membrane separation is 10-80 ℃, and the pressure is 1-5 MPa.
In the first step, the filtering mode adopts one of a plate-frame filter, a bag filter and an automatic cleaning filter, and the aperture of a filter screen is 1-100 mu m.
In the second step, the first-stage membrane separation temperature is 50-60 ℃, and the pressure is 2-4 MPa.
In the third step, the molecular weight of the second-stage membrane separation interception is 500-5000, the temperature of the second-stage membrane separation is 50-60 ℃, and the pressure is 0.25-0.7 MPa.
In the fourth step, the molecular weight of the three-stage membrane separation cut-off is 1000 to 100000, the temperature of the three-stage membrane separation is 30 to 60 ℃, and the pressure is 0.25 to 0.7 MPa.
In the fifth step, the four-stage membrane separation temperature is 20 ℃ to 40 ℃, and the pressure is 2MPa to 4 MPa.
The invention provides a method for recovering hemicellulose, alkali and water from viscose squeezed alkali liquor and also obtains a byproduct sodium sulfate, thereby realizing zero emission of the whole treatment method, compared with the prior nanofiltration technology for recovering alkali, the method can recover the alkali and the water recovered from the viscose squeezed alkali liquor to be reused in different processes of viscose production, simultaneously, the hemicellulose in the viscose squeezed alkali liquor can be completely recovered, and the alkali recovery rate can reach more than 90 percent.
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FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention. The various chemical reagents and chemical articles mentioned in the invention are all the chemical reagents and chemical articles which are well known and commonly used in the prior art, unless otherwise specified; the percentages in the invention are mass percentages unless otherwise specified; the solution in the present invention is an aqueous solution in which the solvent is water, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution, unless otherwise specified; the normal temperature and room temperature in the present invention generally mean a temperature of 15 ℃ to 25 ℃, and are generally defined as 25 ℃.
The invention is further described below with reference to the following examples:
example 1: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor; secondly, separating the pretreated viscose squeezed alkali liquor by a primary membrane to obtain a primary concentrated solution and a primary filtrate respectively, wherein the primary filtrate is purified alkali liquor and can be directly recycled; a third step; adding water into the primary concentrated solution for dialysis, and separating by a secondary membrane to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the secondary filtrate is purified alkali liquor and can be directly recycled; fourthly, adding sulfuric acid into the secondary concentrated solution, adjusting the pH value to 5-7 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, adding water into the third-stage concentrated solution for washing, and performing spray drying to obtain hemicellulose powder; fifthly, separating the third-stage filtrate by a fourth-stage membrane to obtain a fourth-stage concentrated solution and a fourth-stage filtrate respectively, wherein the fourth-stage filtrate is water and can be directly recycled; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
The viscose squeezing alkali liquor has the alkali concentration of 10-30% and the hemicellulose content of 20 g/L-30 g/L, is obtained by soaking the raw materials through alkali treatment, the raw materials of the viscose squeezing alkali liquor can be one or more than one of wood, cotton, straw, sugarcane, bamboo, reed, fiber-containing stem and leaf fibers, preferably wood pulp is used as a cellulose source, the wood pulp source comprises softwood and hardwood, and the hemicellulose content in the wood pulp cellulose can reach 30%.
Example 2: as the optimization of the embodiment, in the second step, a nanofiltration membrane is adopted for primary membrane separation, the rejection rate of the primary membrane to sodium chloride is 60-90%, the primary membrane separation temperature is 10-80 ℃, and the pressure is 1-5 MPa.
Example 3: in the third step, the secondary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the interception molecular weight of the secondary membrane separation is 200-5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1-6 m/s, the secondary membrane separation temperature is 10-80 ℃, and the pressure is 0.1-4 MPa.
Example 4: as the optimization of the above embodiment, in the fourth step, one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane is used for the tertiary membrane separation, the cutoff molecular weight of the tertiary membrane separation is 200 to 100000, the tertiary membrane separation is cross-flow filtration, the flow rate of the membrane surface filtration is 1m/s to 6m/s, the temperature of the tertiary membrane separation is 10 ℃ to 80 ℃, and the pressure is 0.1MPa to 4 MPa.
Example 5: as the optimization of the above embodiment, in the fifth step, one of a nanofiltration membrane and a reverse osmosis membrane is used for the fourth-stage membrane separation, the rejection rate of the fourth-stage membrane to sodium chloride is 95% to 100%, the temperature of the fourth-stage membrane separation is 10 ℃ to 80 ℃, and the pressure is 1MPa to 5 MPa.
Example 6: as the optimization of the above embodiment, in the first step, the filtration mode adopts one of a plate-frame filter, a bag filter and an automatic cleaning filter, and the aperture of the filter screen is 1 μm to 100 μm.
Example 7: as optimization of the above embodiment, in the second step, the primary membrane separation temperature is 50 ℃ to 60 ℃ and the pressure is 2MPa to 4 MPa.
Example 8: as optimization of the above embodiment, in the third step, the molecular weight cut-off of the secondary membrane separation is 500 to 5000, the temperature of the secondary membrane separation is 50 ℃ to 60 ℃, and the pressure is 0.25MPa to 0.7 MPa.
Example 9: as an optimization of the above embodiment, in the fourth step, the molecular weight cut-off of the tertiary membrane separation is 1000 to 100000, the temperature of the tertiary membrane separation is 30 to 60 ℃, and the pressure is 0.25 to 0.7 MPa.
Example 10: as an optimization of the above embodiment, in the fifth step, the four-stage membrane separation temperature is 20 ℃ to 40 ℃ and the pressure is 2MPa to 4 MPa.
Example 11: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor, wherein a plate-and-frame filter is adopted for filtering in a filtering mode, and the aperture of a filtering screen is 1 mu m; secondly, performing primary membrane separation on the pretreated viscose squeezed alkali liquor to obtain primary concentrated liquor and primary filtrate, wherein the primary filtrate is purified alkali liquor and can be directly recycled, the primary membrane separation adopts a nanofiltration membrane, the retention rate of the primary membrane to sodium chloride is 60-90%, the primary membrane separation temperature is 10 ℃, and the pressure is 1 MPa; a third step; adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the secondary filtrate is a purified alkali liquor and can be directly recycled, the secondary membrane separation adopts a tubular nanofiltration membrane, the interception molecular weight of the secondary membrane separation is 200, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1m/s, the secondary membrane separation temperature is 10 ℃, and the pressure is 0.1 MPa; fourthly, adding sulfuric acid into the second-stage concentrated solution, adjusting the pH value to be 5 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, adding water into the third-stage concentrated solution for washing, and performing spray drying to obtain hemicellulose powder, wherein the third-stage membrane separation adopts a tubular nanofiltration membrane, the cutoff molecular weight of the third-stage membrane separation is 1000, the third-stage membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1m/s, the third-stage membrane separation temperature is 10 ℃, and the pressure is 0.1 MPa; fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be directly recycled, the fourth-stage membrane separation adopts a nanofiltration membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 95%, the temperature of the fourth-stage membrane separation is 10 ℃, and the pressure is 1 MPa; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
Example 12: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor, wherein a bag filter is adopted for filtering in a filtering mode, and the aperture of a filter screen is 100 mu m; secondly, performing primary membrane separation on the pretreated viscose squeezed alkali liquor to obtain primary concentrated liquor and primary filtrate, wherein the primary filtrate is purified alkali liquor and can be directly recycled, the primary membrane separation adopts a nanofiltration membrane, the rejection rate of the primary membrane to sodium chloride is 60%, the primary membrane separation temperature is 80 ℃, and the pressure is 5 MPa; a third step; adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the secondary filtrate is purified alkali liquor and can be directly recycled, the secondary membrane separation adopts an ultrafiltration membrane, the interception molecular weight of the secondary membrane separation is 5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 6m/s, the secondary membrane separation temperature is 80 ℃, and the pressure is 4 MPa; fourthly, adding sulfuric acid into the secondary concentrated solution, adjusting the pH value to 7 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a three-stage concentrated solution and a three-stage filtrate, washing the three-stage concentrated solution with water, and performing spray drying to obtain hemicellulose powder, wherein the three-stage membrane separation adopts an ultrafiltration membrane, the cutoff molecular weight of the three-stage membrane separation is 100000, the three-stage membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 6m/s, the three-stage membrane separation temperature is 80 ℃, and the pressure is 4 MPa; fifthly, respectively obtaining a four-stage concentrated solution and a four-stage filtrate after the three-stage filtrate is subjected to four-stage membrane separation, wherein the four-stage filtrate is water and can be directly recycled, the four-stage membrane separation adopts a reverse osmosis membrane, the rejection rate of the four-stage membrane to sodium chloride is 100%, the four-stage membrane separation temperature is 80 ℃, and the pressure is 5 MPa; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
Example 13: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor, wherein an automatic cleaning filter is adopted for filtering in a filtering mode, and the aperture of a filtering screen is 50 microns; secondly, performing primary membrane separation on the pretreated viscose squeezed alkali liquor to obtain primary concentrated liquor and primary filtrate, wherein the primary filtrate is purified alkali liquor and can be directly recycled, the primary membrane separation adopts a nanofiltration membrane, the retention rate of the primary membrane on sodium chloride is 90%, the primary membrane separation temperature is 40 ℃, and the pressure is 3 MPa; a third step; adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate, wherein the secondary filtrate is purified alkali liquor and can be directly recycled, the secondary membrane separation adopts a plate nanofiltration membrane, the secondary membrane separation cutoff molecular weight is 3000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 3m/s, the secondary membrane separation temperature is 40 ℃, and the pressure is 2 MPa; fourthly, adding sulfuric acid into the second-stage concentrated solution, adjusting the pH value to 6 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, adding water into the third-stage concentrated solution for washing, and performing spray drying to obtain hemicellulose powder, wherein the third-stage membrane separation plate type nanofiltration membrane has the cutoff molecular weight of 50000, the third-stage membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 3m/s, the third-stage membrane separation temperature is 40 ℃, and the pressure is 2 MPa; fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be directly recycled, the fourth-stage membrane separation adopts a nanofiltration membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 98%, the temperature of the fourth-stage membrane separation is 40 ℃, and the pressure is 3 MPa; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
The following is a study of the alkali recovery in the method for the zero-release treatment of viscose press lye according to the invention, and is described in connection with example 14, example 15, example 16 and example 17.
Example 14: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method:
firstly, filtering viscose alkali squeezed liquid with the alkali content of 150 g/L-200 g/L and the hemicellulose content of 20 g/L-30 g/L at 100m by a plate-and-frame filter with the mesh size of 1-100 mu m to obtain pretreated viscose squeezed alkali liquid;
secondly, separating the pretreated viscose squeezed alkali liquor by a primary membrane to obtain primary concentrated solution and primary filtrate respectively, wherein the hemicellulose content in the primary concentrated solution is 50 g/L-100 g/L, the hemicellulose content in the primary filtrate is 1 g/L-10 g/L, and the alkali concentration is 150 g/L-200 g/L;
thirdly, adding water into the primary concentrated solution for dialysis, and separating by using a secondary membrane to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the content of hemicellulose in the secondary concentrated solution is 100 g/L-500 g/L, the content of alkali in the secondary concentrated solution is lower than 10 g/L, the secondary filtrate is purified alkali liquor, and the content of alkali in the secondary filtrate is lower and can be used for burdening, washing and the like of each process in the production process of viscose glue, wherein the secondary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the interception molecular weight of the secondary membrane separation is 500-5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1-6 m/s, the secondary membrane separation temperature is 50-60 ℃, and the pressure is 0.25-0.7 MPa;
fourthly, adding 30% sulfuric acid solution into the secondary concentrated solution, adjusting the pH value to be 5-7, precipitating hemicellulose to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, and performing tertiary membrane separation to obtain a tertiary concentrated solution and a tertiary filtrate respectively, wherein the hemicellulose content in the tertiary concentrated solution is 20-30%, the alkali content is lower than 1%, the tertiary concentrated solution is washed by adding water, and spray drying is performed to obtain hemicellulose powder, wherein the tertiary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the cutoff molecular weight of the tertiary membrane separation is 1000-100000, the tertiary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1-6 m/s, the tertiary membrane separation temperature is 30-60 ℃, and the pressure is 0.25-0.7 MPa;
fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be reused as process water, the total dissolved solid content of sodium sulfate in the fourth-stage concentrated solution is 10-20%, the fourth-stage membrane separation adopts one of a nanofiltration membrane and a reverse osmosis membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 95-100%, the temperature of the fourth-stage membrane separation is 20-40 ℃, and the pressure is 2-4 MPa;
and sixthly, sending the four-stage concentrated solution to an evaporative crystallizer for further evaporative crystallization, and centrifuging and drying to obtain solid sodium sulfate.
Example 15: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method:
step one, filtering viscose alkali squeezed liquid with alkali content of 150 g/L and hemicellulose content of 20 g/L in 100m through a plate-and-frame filter with the filter screen mesh aperture of 100 mu m to obtain pretreated viscose squeezed alkali liquid;
secondly, after the pretreated viscose squeezed alkali liquor is subjected to primary membrane separation, primary concentrated liquor and primary filtrate are respectively obtained, wherein the content of hemicellulose in the primary concentrated liquor is 50 g/L, the content of hemicellulose in the primary filtrate is 10 g/L, and the alkali concentration is 150 g/L;
thirdly, adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the content of hemicellulose in the secondary concentrated solution is 100 g/L, the content of alkali in the secondary concentrated solution is lower than 5 g/L, the secondary filtrate is purified alkali liquor, the content of alkali in the secondary filtrate is low, and the secondary filtrate can be used for ingredients, washing water and the like of each process in the production process of viscose, wherein the secondary membrane separation adopts a tubular nanofiltration membrane, the interception molecular weight of the secondary membrane separation is 500, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 5m/s, the secondary membrane separation temperature is 50 ℃, and the pressure is 0.25 MPa;
fourthly, adding 30% sulfuric acid solution into the second-stage concentrated solution, adjusting the pH value to 7, separating out hemicellulose to obtain a hemicellulose suspension, adding water into the hemicellulose suspension for dialysis, and performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, wherein the hemicellulose content in the third-stage concentrated solution is 20%, the alkali content is lower than 1%, the third-stage concentrated solution is washed by adding water, and spray drying is performed to obtain hemicellulose powder, wherein the third-stage membrane separation adopts a tubular nanofiltration membrane, the cutoff molecular weight of the third-stage membrane separation is 1000, the third-stage membrane separation mode is cross flow filtration, the membrane surface filtration flow rate is 5m/s, the third-stage membrane separation temperature is 30 ℃, and the pressure is 0.25 MPa;
fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be reused as process water, and the total dissolved solid content of sodium sulfate in the fourth-stage concentrated solution is 200 g/L, the fourth-stage membrane separation adopts a nanofiltration membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 95%, the temperature of the fourth-stage membrane separation is 20 ℃, and the pressure is 2 MPa;
and sixthly, sending the four-stage concentrated solution to an evaporative crystallizer for further evaporative crystallization, and centrifuging and drying to obtain solid sodium sulfate.
Example 16: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method:
step one, filtering the viscose alkali squeezed liquid with alkali content of 200 g/L and hemicellulose content of 30 g/L and obtained by 100m through a plate and frame filter with the filter screen mesh diameter of 1 mu m to obtain pretreated viscose squeezed alkali liquid;
secondly, after the pretreated viscose squeezed alkali liquor is subjected to primary membrane separation, primary concentrated liquor and primary filtrate are respectively obtained, wherein the content of hemicellulose in the primary concentrated liquor is 100 g/L, the content of hemicellulose in the primary filtrate is 5 g/L, and the alkali concentration is 200 g/L;
thirdly, adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the content of hemicellulose in the secondary concentrated solution is 200 g/L, the content of alkali in the secondary concentrated solution is lower than 10 g/L, the secondary filtrate is purified alkali liquor, the content of alkali in the secondary filtrate is lower, and the secondary filtrate can be used for ingredients, washing water and the like of each process in the production process of viscose, wherein the secondary membrane separation adopts an ultrafiltration membrane, the secondary membrane separation cutoff molecular weight is 5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 56m/s, the secondary membrane separation temperature is 60 ℃, and the pressure is 0.7 MPa;
fourthly, adding 30% sulfuric acid solution into the secondary concentrated solution, adjusting the pH value to be 6, separating out hemicellulose to obtain hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, and performing tertiary membrane separation to obtain tertiary concentrated solution and tertiary filtrate respectively, wherein the hemicellulose content in the tertiary concentrated solution is 30%, the alkali content is lower than 1%, the tertiary concentrated solution is washed by adding water, and spray drying is performed to obtain hemicellulose powder, wherein the tertiary membrane separation adopts an ultrafiltration membrane, the cutoff molecular weight of the tertiary membrane separation is 100000, the tertiary membrane separation mode is cross flow filtration, the membrane surface filtration flow rate is 5m/s, the tertiary membrane separation temperature is 60 ℃, and the pressure is 0.7 MPa;
fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be reused as process water, and the total dissolved solid content of sodium sulfate in the fourth-stage concentrated solution is 200 g/L, the fourth-stage membrane separation adopts a reverse osmosis membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 98%, the temperature of the fourth-stage membrane separation is 40 ℃, and the pressure is 4 MPa;
and sixthly, sending the four-stage concentrated solution to an evaporative crystallizer for further evaporative crystallization, and centrifuging and drying to obtain solid sodium sulfate.
Example 17: the zero-emission treatment method of the viscose squeezed alkali liquor is carried out according to the following method:
step one, filtering the viscose alkali squeezed liquid with the alkali content of 180 g/L and the hemicellulose content of 25 g/L and the alkali content of 100m through a plate-and-frame filter with the filter screen mesh size of 50 mu m to obtain pretreated viscose squeezed alkali liquid;
secondly, after the pretreated viscose squeezed alkali liquor is subjected to primary membrane separation, primary concentrated liquor and primary filtrate are respectively obtained, wherein the content of hemicellulose in the primary concentrated liquor is 70 g/L, the content of hemicellulose in the primary filtrate is 8 g/L, and the alkali concentration is 180 g/L;
thirdly, adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively, wherein the content of hemicellulose in the secondary concentrated solution is 150 g/L, the content of alkali in the secondary concentrated solution is lower than 10 g/L, the secondary filtrate is purified alkali liquor, the content of alkali in the secondary filtrate is low, and the secondary filtrate can be used for ingredients, washing water and the like of each process in the production process of viscose, wherein the secondary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the interception molecular weight of the secondary membrane separation is 3000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 5m/s, the secondary membrane separation temperature is 55 ℃, and the pressure is 0.5 MPa;
fourthly, adding 30% sulfuric acid solution into the secondary concentrated solution, adjusting the pH value to be 5-7, separating out hemicellulose to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, and performing tertiary membrane separation to obtain a tertiary concentrated solution and a tertiary filtrate respectively, wherein the hemicellulose content in the tertiary concentrated solution is 25%, the alkali content is lower than 1%, the tertiary concentrated solution is washed by adding water, and spray drying is performed to obtain hemicellulose powder, wherein the tertiary membrane separation adopts one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane, the cutoff molecular weight of the tertiary membrane separation is 50000, the tertiary membrane separation mode is cross flow filtration, the membrane surface filtration flow rate is 5m/s, the tertiary membrane separation temperature is 45 ℃, and the pressure is 0.5 MPa;
fifthly, respectively obtaining a fourth-stage concentrated solution and a fourth-stage filtrate after the third-stage filtrate is subjected to fourth-stage membrane separation, wherein the fourth-stage filtrate is water and can be reused as process water, the total dissolved solid content of sodium sulfate in the fourth-stage concentrated solution is 10-20%, the fourth-stage membrane separation adopts one of a nanofiltration membrane and a reverse osmosis membrane, the rejection rate of the fourth-stage membrane to sodium chloride is 96%, the temperature of the fourth-stage membrane separation is 30 ℃, and the pressure is 3 MPa;
and sixthly, sending the four-stage concentrated solution to an evaporative crystallizer for further evaporative crystallization, and centrifuging and drying to obtain solid sodium sulfate.
As shown in FIG. 1, it can be seen from examples 15, 16 and 17 of the present invention that the alkali recovery rates from the viscose press lye in examples 15 to 17 of the present invention were 92%, 95% and 94%, respectively.
In conclusion, the invention provides a method for recovering hemicellulose, alkali and water from viscose squeezed alkali liquor and also obtaining a byproduct sodium sulfate, so that the whole treatment method realizes zero emission, compared with the prior nanofiltration technology for recovering alkali, the method provided by the invention can recover alkali and water from the viscose squeezed alkali liquor to be reused in different processes of viscose production, and simultaneously, the hemicellulose in the viscose squeezed alkali liquor can be completely recovered, and the alkali recovery rate can reach more than 90%.
The technical characteristics form an embodiment of the invention, which has strong adaptability and implementation effect, and unnecessary technical characteristics can be increased or decreased according to actual needs to meet the requirements of different situations.
Claims (10)
1. A zero-emission treatment method of viscose squeezed alkali liquor is characterized by comprising the following steps: firstly, filtering the viscose squeezed alkali liquor to obtain pretreated viscose squeezed alkali liquor; secondly, separating the pretreated viscose squeezed alkali liquor by a primary membrane to obtain a primary concentrated solution and a primary filtrate respectively; a third step; adding water into the primary concentrated solution for dialysis, and performing secondary membrane separation to obtain a secondary concentrated solution and a secondary filtrate respectively; fourthly, adding sulfuric acid into the secondary concentrated solution, adjusting the pH value to 5-7 to obtain a hemicellulose turbid liquid, adding water into the hemicellulose turbid liquid for dialysis, performing three-stage membrane separation to obtain a third-stage concentrated solution and a third-stage filtrate respectively, adding water into the third-stage concentrated solution for washing, and performing spray drying to obtain hemicellulose powder; fifthly, separating the third-stage filtrate by a fourth-stage membrane to obtain a fourth-stage concentrated solution and a fourth-stage filtrate respectively; and sixthly, evaporating, crystallizing, centrifuging and drying the four-stage concentrated solution to obtain solid sodium sulfate.
2. The zero-emission treatment method of the viscose squeezing alkali liquor as claimed in claim 1, wherein in the second step, a nanofiltration membrane is used for primary membrane separation, the rejection rate of the primary membrane to sodium chloride is 60% to 90%, the primary membrane separation temperature is 10 ℃ to 80 ℃, and the pressure is 1MPa to 5 MPa.
3. The zero-emission treatment method of the viscose squeezing alkali liquor according to claim 1 or 2, characterized in that in the third step, one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane is adopted for secondary membrane separation, the molecular weight of the secondary membrane separation cut-off is 200 to 5000, the secondary membrane separation mode is cross-flow filtration, the membrane surface filtration flow rate is 1m/s to 6m/s, the secondary membrane separation temperature is 10 ℃ to 80 ℃, and the pressure is 0.1MPa to 4 MPa.
4. The zero-emission treatment method of the viscose squeezing alkali liquor according to the claim 1, the claim 2 or the claim 3, characterized in that in the fourth step, one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane is adopted for the third-stage membrane separation, the cutoff molecular weight of the third-stage membrane separation is 200 to 100000, the cross flow filtration is adopted for the third-stage membrane separation mode, the flow rate of the membrane surface filtration is 1m/s to 6m/s, the temperature of the third-stage membrane separation is 10 ℃ to 80 ℃, and the pressure is 0.1MPa to 4 MPa.
5. The zero-emission treatment method of the viscose squeezing alkali liquor according to the claim 1, 2, 3 or 4, characterized in that in the fourth step, one of a tubular nanofiltration membrane, a plate nanofiltration membrane and an ultrafiltration membrane is adopted for the tertiary membrane separation, the cutoff molecular weight of the tertiary membrane separation is 200 to 100000, the tertiary membrane separation mode is cross flow filtration, the flow rate of the membrane surface filtration is 1m/s to 6m/s, the temperature of the tertiary membrane separation is 10 ℃ to 80 ℃, and the pressure is 0.1MPa to 4 MPa.
6. The zero-emission treatment method of the viscose squeezing alkali liquor according to the claim 1, 2, 3, 4 or 5, characterized in that in the fifth step, one of a nanofiltration membrane and a reverse osmosis membrane is adopted for four-stage membrane separation, the rejection rate of the four-stage membrane to sodium chloride is 95% to 100%, the temperature of the four-stage membrane separation is 10 ℃ to 80 ℃, and the pressure is 1MPa to 5 MPa.
7. The zero-emission treatment method of the viscose squeezing lye as claimed in any one of the claims 1 to 6, characterized in that in the first step, the filtration mode adopts one of a plate-and-frame filter, a bag filter and an automatic cleaning filter, and the aperture of the filter screen is 1 μm to 100 μm.
8. The method for the zero-emission treatment of viscose squeezing lye as claimed in any of the claims 1 to 7 wherein in the second step the primary membrane separation temperature is 50 ℃ to 60 ℃ and the pressure is 2MPa to 4 MPa.
9. The zero-emission treatment method of viscose squeezing lye as claimed in any of the claims 1 to 8 wherein in the third step the secondary membrane separation cut off molecular weight is 500 to 5000, the secondary membrane separation temperature is 50 ℃ to 60 ℃ and the pressure is 0.25MPa to 0.7 MPa.
10. The zero-emission treatment method of the viscose squeezing alkali liquor according to any one of claims 1 to 9, characterized in that in the fourth step, the molecular weight cut-off of the tertiary membrane separation is 1000 to 100000, the temperature of the tertiary membrane separation is 30 ℃ to 60 ℃, and the pressure is 0.25MPa to 0.7 MPa; or/and in the fifth step, the temperature of the four-stage membrane separation is 20-40 ℃, and the pressure is 2-4 MPa.
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| CN114247210A (en) * | 2021-12-28 | 2022-03-29 | 宜宾丝丽雅股份有限公司 | Method and system for recycling alkali liquor in viscose production |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103572635A (en) * | 2013-05-28 | 2014-02-12 | 上海凯鑫分离技术有限公司 | Processing and recovering process of chemical fiber pulp cellulose alkali pressed liquor |
| CN105525389A (en) * | 2014-10-24 | 2016-04-27 | 上海凯鑫分离技术有限公司 | Chemical pulp cellulose alkali squeezing liquid zero-discharge recovery technology |
| CN106145496A (en) * | 2016-08-03 | 2016-11-23 | 上海凯鑫分离技术股份有限公司 | The comprehensive utilization process of viscose fiber acid waste water |
| CN106242101A (en) * | 2015-06-12 | 2016-12-21 | 上海凯鑫分离技术股份有限公司 | The process recovery process of alkali pressed liquor in production process of viscose fiber |
| CN107572697A (en) * | 2017-09-26 | 2018-01-12 | 杭州蓝然环境技术股份有限公司 | A kind of viscose rayon spent lye resource utilization method |
| CN109133448A (en) * | 2018-11-06 | 2019-01-04 | 宜宾海丝特纤维有限责任公司 | A kind of the environment-friendly cycle treatment process and system of viscose glue waste liquid |
| CN109336064A (en) * | 2018-11-06 | 2019-02-15 | 宜宾海丝特纤维有限责任公司 | A kind of viscose sodium sulfate waste liquor multi-level handling system |
| CN109529625A (en) * | 2018-11-28 | 2019-03-29 | 宜宾丝丽雅股份有限公司 | A kind of continuous nanofiltration technique of lye |
| CN209322625U (en) * | 2018-11-06 | 2019-08-30 | 宜宾海丝特纤维有限责任公司 | A kind of environment-friendly cycle processing system of viscose glue waste liquid |
| CN110559861A (en) * | 2019-08-22 | 2019-12-13 | 唐山三友远达纤维有限公司 | Continuous membrane treatment method for alkali squeezing liquid in viscose fiber production process |
-
2020
- 2020-05-29 CN CN202010477696.2A patent/CN111484569A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103572635A (en) * | 2013-05-28 | 2014-02-12 | 上海凯鑫分离技术有限公司 | Processing and recovering process of chemical fiber pulp cellulose alkali pressed liquor |
| CN105525389A (en) * | 2014-10-24 | 2016-04-27 | 上海凯鑫分离技术有限公司 | Chemical pulp cellulose alkali squeezing liquid zero-discharge recovery technology |
| CN106242101A (en) * | 2015-06-12 | 2016-12-21 | 上海凯鑫分离技术股份有限公司 | The process recovery process of alkali pressed liquor in production process of viscose fiber |
| CN106145496A (en) * | 2016-08-03 | 2016-11-23 | 上海凯鑫分离技术股份有限公司 | The comprehensive utilization process of viscose fiber acid waste water |
| CN107572697A (en) * | 2017-09-26 | 2018-01-12 | 杭州蓝然环境技术股份有限公司 | A kind of viscose rayon spent lye resource utilization method |
| CN109133448A (en) * | 2018-11-06 | 2019-01-04 | 宜宾海丝特纤维有限责任公司 | A kind of the environment-friendly cycle treatment process and system of viscose glue waste liquid |
| CN109336064A (en) * | 2018-11-06 | 2019-02-15 | 宜宾海丝特纤维有限责任公司 | A kind of viscose sodium sulfate waste liquor multi-level handling system |
| CN209322625U (en) * | 2018-11-06 | 2019-08-30 | 宜宾海丝特纤维有限责任公司 | A kind of environment-friendly cycle processing system of viscose glue waste liquid |
| CN109529625A (en) * | 2018-11-28 | 2019-03-29 | 宜宾丝丽雅股份有限公司 | A kind of continuous nanofiltration technique of lye |
| CN110559861A (en) * | 2019-08-22 | 2019-12-13 | 唐山三友远达纤维有限公司 | Continuous membrane treatment method for alkali squeezing liquid in viscose fiber production process |
Non-Patent Citations (2)
| Title |
|---|
| 盛宁 等: "自粘胶纤维生产废碱中回收碱液和半纤维素工艺", 《人造纤维》 * |
| 高红武: "《"三废"处理及综合利用》", 30 September 2005, 中国环境科学出版社 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114247210A (en) * | 2021-12-28 | 2022-03-29 | 宜宾丝丽雅股份有限公司 | Method and system for recycling alkali liquor in viscose production |
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