CN110496486A - A kind of purification method of fermented feed production tail gas - Google Patents

Abstract

The invention belongs to the technical field of tail gas treatment, in particular to a method for purifying tail gas from fermented feed production. The present invention adopts a four-step continuous treatment method, that is, dust, volatile organic acids, hydrogen sulfide gas, alcohol, ester and other odorous gases are respectively purified by bag dust removal, lye absorption, high-pressure spray adsorption, and biological liquid spray. The process of the invention has high tail gas odor removal rate, low cost, high efficiency, environmental protection and no secondary pollution, and is suitable for large-scale popularization and application in the fermented feed industry.

Description

A method for purifying tail gas from fermented feed production

technical field

The invention belongs to the technical field of tail gas treatment, in particular to a method for purifying tail gas from fermented feed production.

Background technique

During the feed fermentation process, a large amount of organic acids such as acetic acid and lactic acid, as well as volatile odor gases such as hydrogen sulfide, mercaptan and ammonia will be produced. Especially during the drying process of fermented feed, a large amount of volatile substances are emitted along with water vapor and dust. If not handled properly, it will cause certain pollution to the environment and seriously affect the environment of surrounding residents. With the gradual enhancement of people's awareness of environmental protection, the standards and supervision of industrial exhaust emissions have become more stringent. Direct discharge of fermented feed production tail gas without treatment will be prohibited and punished by relevant regulatory authorities.

At present, the commonly used method of purifying the tail gas of fermented feed mainly adopts alkali solution absorption, and then discharges after washing and spraying. This simple treatment method is difficult to completely treat the odorous substances in the tail gas of fermented feed, and the exhaust gas emission during the drying process is very large, and only one alkali washing and one spraying cannot meet the needs of safe discharge.

Contents of the invention

The present invention aims at the deficiencies in the above-mentioned prior art, and provides a method for purifying the tail gas produced by fermented feed.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

A method for purifying tail gas from fermented feed production, the steps are as follows:

(1) Dust removal by bag filter: During the drying process of fermented feed, the tail gas dried by the boiling dryer is subjected to primary dust removal through the bag filter under the action of the exhaust fan;

(2) Alkali absorption: The tail gas treated in step (1) is passed into the lye spray room, the top of the lye spray room is equipped with an atomizing nozzle, the lower layer is the lye circulation pool, and the lye circulation pool passes through the lye The adding pump is connected to the lye storage tank; the tail gas enters from the side of the lye spray room, and is sprayed and absorbed by the densely arranged atomizing nozzles on the top to remove the irritating gas and perform secondary dust removal at the same time;

(3) High-pressure spray adsorption: the tail gas processed in step (2) enters the exhaust pipe, and a high-pressure spray nozzle is installed in the exhaust pipe, and the deodorizing adsorbent is pressurized to the high-pressure spray nozzle to atomize to form droplets, The tail gas is deodorized and cooled;

(4) Biological liquid spraying: The tail gas treated in step (3) enters from the bottom of the biological liquid spray tower under the action of the induced draft fan, and the biological absorption liquid in the biological liquid spray tower is sprayed in multiple layers from top to bottom. Spraying, the tail gas is discharged at high altitude after spraying treatment.

Further, in step (2), the lye in the lye storage tank is supplemented with high-concentration lye in the lye circulation pool by the lye addition pump according to the flow rate of 100-200mL/min, so as to ensure the pH value of the lye in the lye circulation pool Control it at 8-10.

Furthermore, the solute substance in the lye is sodium hydroxide, potassium hydroxide, quicklime, sodium carbonate or sodium bicarbonate; the lye in the lye storage tank is prepared as follows: add 400-500g of solute substance.

The beneficial effect of adopting the above-mentioned further scheme is that after the tail gas is sprayed and absorbed by the lye, and the irritating acid gases such as hydrogen sulfide and organic acid are removed, the lye concentration and lye pH value in the lye circulation pool will be reduced, so it will continue to The lye circulating pool is supplemented with high-concentration lye to ensure the effect of lye spraying and absorption.

Further, in step (3), the exhaust pipe has a diameter of 1 meter and a length of 10 meters, and a high-pressure spray nozzle is set every 5 meters apart; the deodorizing adsorbent in the storage tank is pressurized to 0.4 MPa by using a high-pressure pump, and the deodorizing adsorption The agent is atomized through a high-pressure spray nozzle to form droplets with a diameter of 3-10 μm.

Further, in step (3), the deodorizing adsorbent is composed of 3-9 parts by weight of cationic surfactant, 1-3 parts by weight of nano silicon dioxide and 500-1000 parts by weight of water.

Furthermore, the cationic surfactant is cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide or octadecyldimethylammonium chloride.

The beneficial effect of adopting the above-mentioned further scheme is that the cationic surfactant is positively charged in aqueous solution and has a strong adsorption force, and the nano-silica has the characteristics of small particle size, good dispersibility, and large specific surface area. After being atomized by the high-pressure spray nozzle, it fully contacts with the odor gas molecules and captures them quickly to achieve the effect of exhaust gas purification.

Further, in step (4), the preparation method of the biological absorption liquid is as follows:

(1) Mix photosynthetic bacteria culture fluid, yeast culture fluid, lactic acid bacteria culture fluid, actinomycetes culture fluid, filamentous bacteria culture fluid, and acetic acid bacteria culture fluid in a weight ratio of 2:2:2:1:1:1, get the mixture;

(2) Take the mixed solution of step (1), insert it into the sterilized medium, ventilate it for 1 hour every 12 hours, and after culturing for 60 days, dilute it with water 1000-2000 times as a bioabsorption solution.

Further, in the step (1), the photosynthetic bacteria culture solution is composed of 0.2% ammonium chloride, 0.02% dipotassium hydrogen phosphate, 0.4% sodium acetate, 0.2% sodium bicarbonate, 0.1% sodium chloride by weight percentage , 0.015% yeast extract, 0.02% magnesium sulfate, and 99.045% water, which are autoclaved at 121°C, inoculated with photosynthetic bacteria powder according to the inoculation amount of 5% of the photosynthetic bacteria culture solution weight, and obtained after aerobic cultivation at 30°C for 7 days;

The yeast culture solution is composed of 1% yeast extract, 2% peptone, 2% glucose, and 95% water in terms of weight percentage, and is sterilized by autoclaving at 121° C., and the yeast is inoculated according to the inoculation amount of 1% of the weight of the yeast culture solution. Bacteria powder, obtained after aerobic culture at 28°C for 48 hours;

The lactic acid bacteria culture solution is composed of 0.75% yeast extract, 0.75% peptone, 1% glucose, 0.02% KH ₂ PO ₄ , 0.05% Tween 80, and 97.43% water in terms of weight percentage, and is sterilized by high pressure at 121°C according to Inoculate the lactic acid bacteria powder with 1% inoculum weight of the lactic acid bacteria culture solution, and obtain it after anaerobic culture at 37°C for 48 hours;

The actinomycetes culture solution is composed of 2% soluble starch, 0.05% K ₂ HPO ₄ , 0.05% MgSO ₄ ·7H ₂ O, 0.05% NaCl, 0.001% FeSO ₄ , and 97.848% water by weight percentage. ℃ autoclave, inoculate the actinomycetes powder according to the inoculum amount of 1% of the weight of the actinomycetes culture solution, obtain after 7 days of aerobic culture at 28 ℃;

The filamentous bacteria culture solution is calculated by weight percentage, and is sterilized by 1% yeast extract, 2% peptone, 2% glucose, and 95% water by autoclaving at 121 ° C. Bacteria powder, obtained after aerobic culture at 28°C for 7 days;

Described acetic acid bacterium culture fluid is calculated by weight percentage, by 10% glucose, 1% yeast extract, 89% water through 121 ℃ autoclave sterilization, according to the 1% inoculation amount of acetic acid bacterium culture fluid weight inoculation acetic bacteria powder, aerobic Obtained after culturing for 12 hours;

In step (2), the sterilized medium is composed of 3% sugarcane molasses, 2% peptone, and 95% water by weight percentage, and is obtained by autoclaving at 121°C.

Wherein, the photosynthetic bacteria powder, saccharomyces powder, lactic acid bacteria powder, actinomycetes powder, filamentous bacteria powder, and acetic acid bacteria powder used in the present invention were purchased from Shandong Jining Jinshan Bioengineering Co., Ltd.

The beneficial effects of the present invention are:

The present invention adopts a four-step continuous treatment method, that is, dust, volatile organic acids, hydrogen sulfide gas, alcohol, ester and other odorous gases are respectively purified by bag dust removal, lye absorption, high-pressure spray adsorption, and biological liquid spray. The process of the invention has high tail gas odor removal rate, low cost, high efficiency, environmental protection and no secondary pollution, and is suitable for large-scale popularization and application in the fermented feed industry.

Description of drawings

Fig. 1 is the TIC figure of the volatile matter in the untreated tail gas in the embodiment of the present invention 1;

Fig. 2 is a TIC diagram of volatile substances in the treated tail gas in Example 1 of the present invention.

Detailed ways

The principles and features of the present invention are described below in conjunction with examples, which are only used to explain the present invention and are not intended to limit the scope of the present invention.

Example 1

A method for purifying tail gas produced by fermenting peanut meal, the steps are as follows:

(1) Dust removal by bag filter: During the drying process of fermented feed, the tail gas dried by the boiling dryer is subjected to primary dust removal through the bag filter under the action of the exhaust fan;

(2) Alkali absorption: the tail gas treated in step (1) is passed into the lye spray room, the top of the lye spray room is equipped with an atomizing nozzle, the lower layer is the lye circulation pool, and the lye circulation pool passes through the lye Add the pump to connect to the lye storage tank; the tail gas enters from the side of the lye spray room, sprays and absorbs through the densely arranged atomizing nozzles on the top, removes irritating acid gases such as hydrogen sulfide and organic acids, and performs secondary dust removal at the same time;

Wherein, the lye pH value in the control lye circulation pool is 9.5, and the concentration in the lye storage tank is a sodium hydroxide solution of 400g/L;

(3) High-pressure spray adsorption: the tail gas treated in step (2) enters the exhaust pipe, installs a high-pressure spray nozzle in the exhaust pipe, and utilizes a high-pressure pump to pressurize the deodorizing adsorbent in the storage tank to 0.4MPa, deodorizing The odor adsorbent is atomized through the high-pressure spray nozzle to form droplets with a diameter of 3-10 μm, which deodorizes and cools the exhaust gas; aldehydes, pyrazines, and alcohols in the exhaust gas are significantly reduced;

Wherein, the deodorizing adsorbent is composed of 5 parts by weight of cetyltrimethylammonium bromide, 2 parts by weight of nano silicon dioxide and 600 parts by weight of water;

(4) Biological liquid spraying: The tail gas treated in step (3) enters from the bottom of the biological liquid spray tower under the action of the induced draft fan, and the biological absorption liquid in the biological liquid spray tower is sprayed in three layers from top to bottom. Spraying, to further remove the odor gas in the tail gas, the tail gas only contains a small amount of macromolecular alkanes, which meets the emission standards, and the tail gas is discharged at a height of 25 meters after being sprayed.

detection

The components of the fermented feed tail gas in each step of Example 1 were detected by using solid-phase microextraction combined with gas chromatography-mass spectrometer, and the detection method was as follows:

(1) Sample collection: use a gas sampling bag with a silanized inner wall to collect the exhaust gas, seal it, and complete the test within 12 hours;

(2) Activation of the extraction head: select the manual injection (DVB/CAR/PDMS) extraction head of solid phase microextraction, 50/30 μm DVB/CAR on PDMS; Insert the extraction head into the inlet of the GC-MS instrument for activation to remove the substances that were originally adsorbed on the extraction head. The activation time is 30-40 minutes;

(3) Sample injection: Insert the activated extraction head into the tail gas sampling bag in step (1), push out the extraction head, and then absorb in the headspace for 50-60 minutes at a constant temperature of 35-45°C, then analyze at 250°C for 5 minutes;

(4) Gas chromatography conditions:

Capillary column: DB-5MS chromatographic column (30m×0.25mm×0.25μm);

Gas phase column temperature rise program: keep at 40°C for 2 minutes, raise the temperature to 220°C at a heating rate of 5°C/min, and keep for 10 minutes;

Vaporization chamber temperature: 250°C;

Helium flow rate: 0.8mL/min;

Injection method: splitless injection;

(5) Mass spectrometry conditions: electron bombardment ion source (EI); electron energy 70eV; ion source temperature 230°C; filament emission current 200μA; interface temperature 250°C; full-spectrum scanning, scanning mass range m/z 35-450.

The names and related information of unknown compounds were determined by matching with the NIST spectral library (data of 107,000 compounds) by computer search, and only relevant identification results with a similarity greater than 80 (the maximum value was 100) were reported. The relative content of each component was calculated by the peak area normalization method.

Table 1 is the content of volatile substances in the tail gas produced by fermented peanut meal in Example 1; Table 2 is the content of volatile substances in the tail gas after step (2) lye absorption in Example 1; Table 3 is the content of volatile substances in the tail gas in Example 1 The content of volatile substances in the tail gas after step (3) high-pressure spray adsorption; Table 4 shows the content of volatile substances in the tail gas after step (4) biological liquid spraying in Example 1.

Table 1

keep time Substance name Relative content % 2.602 acetic acid 7.25 3.794 pentanol 13.41 5.792 butyric acid 23.32 8.583 Valeric acid 19.97 9.206 2,5-Dimethylpyrazine 5.89 12.031 Trimethylpyrazine 2.67 13.06 Benzyl alcohol 1.25 14.451 3-Ethyl-2,5-dimethylpyrazine 1.7 15.53 Phenyl alcohol 9.77 16.362 Heptane ether 0.77 16.653 3-Methylbutyl Ester 0.6 18.07 Heptanol 5.36 18.223 borneol 1.34 22.669 Furanone 0.22 23.504 Tetradecane 1.11 28.403 Eicosane 0.81

Table 2

table 3

Table 4

keep time Substance name Relative content% 13.06 Benzyl alcohol 5.21 15.53 Phenyl alcohol 5.76 20.309 Nonane 18.15 20.849 dodecane 15.03 23.514 Tetradecane 27.21 28.411 Eicosane 28.64

From the data in Table 1-Table 4, it can be seen that after the tail gas of fermented peanut meal is absorbed by lye, absorbed by cations, and sprayed with biological fluid, the small molecular organic acids, pyrazines, alcohols, esters and other substances in the volatile substances are successively reduced, and finally Only alcohol and alkanes can be detected in the exhaust gas, and the emission standards have been met through third-party testing.

Example 2

A method for purifying tail gas produced by fermenting sesame meal, the steps are as follows:

(1) Dust removal by bag filter: During the drying process of fermented feed, the tail gas dried by the boiling dryer is subjected to primary dust removal through the bag filter under the action of the exhaust fan;

(2) Alkali absorption: The tail gas treated in step (1) is passed into the lye spray room, the top of the lye spray room is equipped with an atomizing nozzle, the lower layer is the lye circulation pool, and the lye circulation pool passes through the lye Add the pump to connect to the lye storage tank; the tail gas enters from the side of the lye spray room, and is sprayed and absorbed by the densely arranged atomizing nozzles on the top to remove irritating acid gases such as hydrogen sulfide and organic acids, and perform secondary dust removal at the same time;

Wherein, the lye pH value in the control lye circulation pool is 8, and the concentration in the lye storage tank is a sodium hydroxide solution of 450g/L;

(3) High-pressure spray adsorption: the tail gas treated in step (2) enters the exhaust pipe, installs a high-pressure spray nozzle in the exhaust pipe, and utilizes a high-pressure pump to pressurize the deodorizing adsorbent in the storage tank to 0.4MPa, deodorizing The odor adsorbent is atomized through the high-pressure spray nozzle to form droplets with a diameter of 3-10 μm, which deodorizes and cools the exhaust gas; aldehydes, pyrazines, and alcohols in the exhaust gas are significantly reduced;

Wherein, the deodorizing adsorbent is composed of 8 parts by weight of octadecyldimethylammonium chloride, 3 parts by weight of nano silicon dioxide and 900 parts by weight of water;

(4) Biological liquid spraying: The tail gas treated in step (3) enters from the bottom of the biological liquid spray tower under the action of the induced draft fan, and the biological absorption liquid in the biological liquid spray tower is sprayed in three layers from top to bottom. Spraying, to further remove the odor gas in the tail gas, the tail gas only contains a small amount of macromolecular alkanes, which meets the emission standards, and the tail gas is discharged at a height of 25 meters after being sprayed.

detection

The components of the fermented feed tail gas in each step of Example 2 were detected by using solid-phase microextraction combined with gas chromatography-mass spectrometer, and the detection method was as follows:

(1) Sample collection: use a gas sampling bag with a silanized inner wall to collect the exhaust gas, seal it, and complete the test within 12 hours;

(2) Activation of the extraction head: select the manual injection (DVB/CAR/PDMS) extraction head of solid phase microextraction, 50/30 μm DVB/CAR on PDMS; Insert the extraction head into the inlet of the GC-MS instrument for activation to remove the substances that were originally adsorbed on the extraction head. The activation time is 30-40 minutes;

(3) Sample injection: Insert the activated extraction head into the tail gas sampling bag in step (1), push out the extraction head, and then absorb in the headspace for 50-60 minutes at a constant temperature of 35-45°C, then analyze at 250°C for 5 minutes;

(4) Gas chromatography conditions:

Capillary column: DB-5MS chromatographic column (30m×0.25mm×0.25μm);

Gas phase column temperature rise program: keep at 40°C for 2 minutes, raise the temperature to 220°C at a heating rate of 5°C/min, and keep for 10 minutes;

Vaporization chamber temperature: 250°C;

Helium flow rate: 0.8mL/min;

Injection method: splitless injection;

(5) Mass spectrometry conditions: electron bombardment ion source (EI); electron energy 70eV; ion source temperature 230°C; filament emission current 200μA; interface temperature 250°C; full-spectrum scanning, scanning mass range m/z 35-450.

The names and related information of unknown compounds were determined by matching with the NIST spectral library (data of 107,000 compounds) by computer search, and only relevant identification results with a similarity greater than 80 (the maximum value was 100) were reported. The relative content of each component was calculated by the peak area normalization method.

Table 5 is the content of volatile substances in the tail gas produced by fermenting sesame meal in Example 2; Table 6 is the content of lye in Example 2 through step (2) lye absorption, step (3) high-pressure spray adsorption, step (4) biological liquid spray The content of volatile substances in the exhaust gas after leaching.

table 5

Table 6

keep time Substance name Relative content% 13.06 Benzyl alcohol 3.86 18.07 Heptanol 6.3 19.741 Phenyl ethyl ester 12.17 20.849 dodecane 18.85 23.514 Tetradecane 29.14 28.411 Eicosane 29.68

It can be seen from the data in Table 5-Table 6 that after the tail gas of fermented sesame meal is purified by the method of the present invention, organic acids, pyrazines and other odorous substances are significantly reduced, and the third detection reaches the emission standard.

The above descriptions 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 principles of the present invention shall be included in the protection of the present invention. within range.

Claims (7)

1. a purification method of fermented feed production tail gas, is characterized in that, step is as follows: (1) Dust removal by bag filter: During the drying process of fermented feed, the tail gas dried by the boiling dryer is subjected to primary dust removal through the bag filter under the action of the exhaust fan; (2) Alkali absorption: The tail gas treated in step (1) is passed into the lye spray room, the top of the lye spray room is equipped with an atomizing nozzle, the lower layer is the lye circulation pool, and the lye circulation pool passes through the lye The adding pump is connected to the lye storage tank; the tail gas enters from the side of the lye spray room, and is sprayed and absorbed by the densely arranged atomizing nozzles on the top to remove the irritating gas and perform secondary dust removal at the same time; (3) High-pressure spray adsorption: the tail gas processed in step (2) enters the exhaust pipe, and a high-pressure spray nozzle is installed in the exhaust pipe, and the deodorizing adsorbent is pressurized to the high-pressure spray nozzle to atomize to form droplets, The tail gas is deodorized and cooled; (4) Biological liquid spraying: The tail gas treated in step (3) enters from the bottom of the biological liquid spray tower under the action of the induced draft fan, and the biological absorption liquid in the biological liquid spray tower is sprayed in multiple layers from top to bottom. Spraying, the tail gas is discharged at high altitude after spraying treatment. 2. purification method according to claim 1, is characterized in that, in step (2), the lye in the lye storage tank replenishes alkali in the lye circulation pool according to the flow velocity of 100-200mL/min by the lye adding pump Liquid, control the pH value of the lye in the lye circulation pool at 8-10. 3. according to claim 1 and 2 described purification methods, it is characterized in that, in step (2), the solute substance in the described lye is sodium hydroxide, potassium hydroxide, unslaked lime, sodium carbonate or sodium bicarbonate; The lye in the lye storage tank is prepared as follows: add 400-500g of solute substances into 1L of water. 4. purification method according to claim 1, is characterized in that, in step (3), described deodorizing adsorbent is made of cationic surfactant 3-9 weight part, nano silicon dioxide 1-3 weight part and water 500-1000 parts by weight. 5. purification method according to claim 4 is characterized in that, described cationic surfactant is hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide Dimethyl ammonium chloride. 6. purification method according to claim 1, is characterized in that, in step (4), the preparation method of biological absorption liquid is as follows: (1) Mix photosynthetic bacteria culture fluid, yeast culture fluid, lactic acid bacteria culture fluid, actinomycetes culture fluid, filamentous bacteria culture fluid, and acetic acid bacteria culture fluid in a weight ratio of 2:2:2:1:1:1, get the mixture; (2) Take the mixed solution of step (1), insert it into the sterilized medium, ventilate it for 1 hour every 12 hours, and after culturing for 60 days, dilute it with water 1000-2000 times as a bioabsorption solution. 7. purification method according to claim 6, is characterized in that, in step (1), described photosynthetic bacteria culture fluid is by weight percentage, is made of 0.2% ammonium chloride, 0.02% dipotassium hydrogen phosphate, 0.4% acetic acid Sodium, 0.2% sodium bicarbonate, 0.1% sodium chloride, 0.015% yeast extract, 0.02% magnesium sulfate, 99.045% water, after autoclaving at 121 ℃, inoculate photosynthetic bacteria according to the inoculation amount of 5% of the weight of photosynthetic bacteria culture solution Bacteria powder, obtained after aerobic culture at 30°C for 7 days; The yeast culture solution is composed of 1% yeast extract, 2% peptone, 2% glucose, and 95% water in terms of weight percentage, and is sterilized by autoclaving at 121° C., and the yeast is inoculated according to the inoculation amount of 1% of the weight of the yeast culture solution. Bacteria powder, obtained after aerobic culture at 28°C for 48 hours; The lactic acid bacteria culture solution is composed of 0.75% yeast extract, 0.75% peptone, 1% glucose, 0.02% KH ₂ PO ₄ , 0.05% Tween 80, and 97.43% water in terms of weight percentage, and is sterilized by high pressure at 121°C according to Inoculate the lactic acid bacteria powder with 1% inoculum weight of the lactic acid bacteria culture solution, and obtain it after anaerobic culture at 37°C for 48 hours; The actinomycetes culture solution is composed of 2% soluble starch, 0.05% K ₂ HPO ₄ , 0.05% MgSO ₄ ·7H ₂ O, 0.05% NaCl, 0.001% FeSO ₄ , and 97.848% water by weight percentage. ℃ autoclave, inoculate the actinomycetes powder according to the inoculum amount of 1% of the weight of the actinomycetes culture solution, obtain after 7 days of aerobic culture at 28 ℃; The filamentous bacteria culture solution is calculated by weight percentage, and is sterilized by 1% yeast extract, 2% peptone, 2% glucose, and 95% water by autoclaving at 121 ° C. Bacteria powder, obtained after aerobic culture at 28°C for 7 days; Described acetic acid bacterium culture fluid is calculated by weight percentage, by 10% glucose, 1% yeast extract, 89% water through 121 ℃ autoclave sterilization, according to the 1% inoculation amount of acetic acid bacterium culture fluid weight inoculation acetic bacteria powder, aerobic Obtained after culturing for 12 hours; In step (2), the sterilized medium is composed of 3% sugarcane molasses, 2% peptone, and 95% water by weight percentage, and is obtained by autoclaving at 121°C.