Waste gas deodorization system and method

Abstract

The invention discloses a waste gas deodorization system and method, and relates to the technical field of waste gas treatment. Comprising a spraying module, a biological deodorization module, a humidifying circulation module, a waste gas treatment module and a control module, the spraying module is used for treating alkaline gas in the waste gas; the humidifying circulating module is used for realizing cyclic utilization of spraying liquid and adjusting the humidity and temperature of waste gas; the biological deodorization module is used for removing part of organic matters in the waste gas; the biological box utilizes the biodegradation effect of microorganisms to realize biological deodorization; the waste gas treatment module is used for treating acid gas in the waste gas to reach the emission standard of the waste gas; the control module adopts a PLC to control operation of equipment in the waste gas treatment process, and automatic control over the waste gas treatment process is achieved. A PLC control system is adopted, equipment can be regulated and controlled in real time according to sensor data, the automatic operation capacity of the equipment can be achieved, and the waste gas deodorization effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment, and in particular to a waste gas deodorization system and method. Background Art

[0002] Malodorous gases, as one of the eight major environmental hazards, not only pollute the ecological environment, but also directly affect people's quality of life and even endanger human health. They have attracted more and more attention. Industrial production, municipal sewage, sludge treatment and garbage disposal facilities are the main sources of malodorous gases. Except for a few inorganic compounds such as hydrogen sulfide and ammonia, the vast majority are organic matter, containing sulfur (S), nitrogen (N), oxygen (O), and chlorine (Cl), which are common components of malodorous substances. Traditional waste gas treatment methods such as physical adsorption and chemical absorption have problems such as high cost, low efficiency, and easy to cause secondary pollution.

[0003] Biological deodorization has become an important method of biological deodorization by using microbial deodorizing bacteria to absorb and deodorize odor molecules in the air in the form of spray, and by adding microbial bacteria at the source to inhibit the generation of odor. However, in the deodorization process, there are also problems such as low automation efficiency and inability to accurately control the operation of the equipment. Summary of the invention

[0004] The object of the present invention is to provide a waste gas deodorization system and method to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a waste gas deodorization system, comprising a spray module, a biological deodorization module, a humidification circulation module, a waste gas treatment module, and a control module;

[0006] The spray module includes an alkaline scrubber, which processes acidic gases in the waste gas by neutralizing the waste gas with an alkaline absorbent, and pre-treats the input waste gas;

[0007] The humidification circulation module includes a circulation water tank and a spray water tank, which are used to realize the recycling of the spray liquid and adjust the humidity and temperature of the exhaust gas;

[0008] The biological deodorization module includes a pre-washing tank and a biological box. The pre-washing tank is connected to the humidification circulation module. The pre-treated waste gas enters the pre-washing tank and contacts with the spray water to remove large particles, some soluble gases and some organic matter in the waste gas through physical and chemical effects.

[0009] The bio-box utilizes the biodegradation effect of microorganisms to adsorb and decompose organic matter in the waste gas to generate carbon dioxide and other inorganic substances for biological deodorization;

[0010] The waste gas treatment module includes an acid washing tower, and the waste gas output from the bio-box undergoes a neutralization reaction with an acid solution to treat the alkaline gas in the waste gas to meet the waste gas emission standards;

[0011] The control module uses PLC to control the operation of the waste gas treatment process equipment to achieve automatic control of the waste gas treatment process.

[0012] Preferably, the spray water tank sprays water mist into the air through a nozzle, and controls the spraying amount by adjusting the opening of the nozzle and the flow of the spray pump to keep the exhaust gas humidity stable; the circulating water tank is equipped with a heating and cooling device to adjust the temperature of the spray liquid to keep the exhaust gas temperature stable.

[0013] Preferably, the bio-box utilizes biodegradation to perform biological deodorization, specifically:

[0014] Gas-liquid diffusion: the odorous waste gas diffuses through the gas-liquid interface and transfers from the gas phase to the liquid phase;

[0015] Liquid-solid diffusion: the odorous waste gas dissolved in the liquid phase diffuses to the surface of the microbial membrane. The odor molecules in the odorous waste gas diffuse from the liquid phase to the biofilm of the biological filler and are adsorbed and absorbed by the microorganisms.

[0016] Biological oxidation: the microorganisms in the biofilm formed on the surface of the biological filler oxidize and decompose the adsorbed odor molecules. The microorganisms use the odor molecules as nutrients and decompose them into harmless or low-harm water and carbon dioxide through the metabolic process, and cause the diffusion and absorption of nutrients such as nitrogen or phosphorus and oxygen;

[0017] Microbial growth and inhibition: enzymes and antimicrobial peptides produced during microbial growth inhibit the growth of corrupt microorganisms and are used for preservation and to inhibit the generation of odors.

[0018] Preferably, the biological deodorization module is a box-type structure, with a nutrient solution storage tank and automatic humidity control equipment at the bottom; the middle part is the organisms and fillers; the upper part is provided with a waste gas inlet, a qualified gas outlet and a spray automatic circulation system.

[0019] Preferably, the PLC is specifically:

[0020] S1. Preset the range of target values ​​of spraying amount, humidification amount, temperature and flow rate in PLC;

[0021] S2, collect parameter data in real time through sensors installed in the exhaust gas deodorization system;

[0022] S3, PLC processes and analyzes the received sensor data to obtain the error between the current state and the set value. The specific calculation is:

[0023] The PID control algorithm is used to calculate the total control output, and the formula is:

[0024]

[0025] Where, e(t) is the deviation at time t, that is, the difference between the set value and the actual value, K p is the proportional gain, which determines the immediate response of the controller to the deviation, K i is the integral gain, which determines the controller's response to the accumulated deviation and is used to eliminate the steady-state error. d is the derivative gain, which determines the controller’s response to the rate of change of the error;

[0026] The calculation formula for spray volume control is:

[0027] Spray Pump Output=K s HumidityError;

[0028] Among them, K s For the spray control gain, the humidity error is calculated based on the data from the humidity sensor, and the flow rate of the spray pump is adjusted;

[0029] The humidification control calculation formula is:

[0030] Humidifier Output=K h Humidity Error;

[0031] Among them, K h For humidification control gain, the humidity error is calculated based on the data from the humidity sensor, and the spraying amount of the humidifier is adjusted;

[0032] The temperature control calculation formula is:

[0033] Heater (Cooler) Output = K t Temperature Error:

[0034] Among them, K t For temperature control gain, based on the data from the temperature sensor, the temperature error is calculated and the output of the heating or cooling device is adjusted;

[0035] The flow control calculation formula is:

[0036] Flow Control Valve Output=K f Flow Error;

[0037] Among them, K fFor flow control gain, the flow error is calculated based on the data of the flow sensor, and the opening of the flow control valve is adjusted;

[0038] S4. According to the results of data processing, the PLC controls the operating status of the equipment and sends control signals to regulate the operation of the equipment to achieve automated control of the waste gas deodorization process.

[0039] The present invention also provides a method for deodorizing waste gas, which is specifically:

[0040] The collected waste gas is pre-treated through an alkali scrubber to reduce the acidic pollutant content in the waste gas;

[0041] The pre-treated waste gas is humidified by a humidifier to meet the humidity conditions for microbial growth;

[0042] The humidified waste gas passes through the biofilter, and the microbial flora on the surface of the biological carrier captures the pollutants in the waste gas and reproduces rapidly in the biofilter;

[0043] The microbial flora decomposes the captured pollutants into carbon dioxide and other inorganic substances, and treats harmful substances in the exhaust gas;

[0044] The waste gas treated by the biological filter is discharged to achieve the purpose of deodorization.

[0045] Beneficial effects of the present invention: The present invention utilizes the natural degradation ability of microorganisms to convert harmful gases into carbon dioxide and inorganic substances, thereby reducing pollution to the environment; under waste gas conditions, microorganisms can rapidly reproduce and decompose harmful pollutants by adsorbing and converting substances in waste gas, thereby improving the deodorization efficiency of waste gas; the waste gas deodorization system adopts a PLC control system, which can regulate the equipment in real time according to sensor data, realize the automatic operation capability of the equipment, and improve the deodorization effect of waste gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the waste gas deodorization system of the present invention.

[0047] Figure 2 This is the working principle diagram of the biological washing, filtration and deodorization system.

[0048] Figure 3 It is a flow chart of the waste gas treatment method of the present invention. DETAILED DESCRIPTION

[0049] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0050] Reference Figure 1 , the waste gas deodorization system includes a spray module, a biological deodorization module, a humidification circulation module, a waste gas treatment module, and a control module;

[0051] The spray module includes an alkaline scrubber, which processes acidic gases in the waste gas by neutralizing the waste gas with an alkaline absorbent, and pre-treats the input waste gas;

[0052] The humidification circulation module includes a circulation water tank and a spray water tank, which are used to realize the recycling of the spray liquid and adjust the humidity and temperature of the exhaust gas;

[0053] The biological deodorization module includes a pre-washing tank and a biological box. The pre-washing tank is connected to the humidification circulation module. The pre-treated waste gas enters the pre-washing tank and contacts with the spray water to remove large particles, some soluble gases and some organic matter in the waste gas through physical and chemical effects.

[0054] The bio-box utilizes the biodegradation effect of microorganisms to adsorb and decompose organic matter in the waste gas to generate carbon dioxide and other inorganic substances for biological deodorization;

[0055] The waste gas treatment module includes an acid washing tower, and the waste gas output from the bio-box undergoes a neutralization reaction with an acid solution to treat the alkaline gas in the waste gas to meet the waste gas emission standards;

[0056] The control module uses PLC to control the operation of the waste gas treatment process equipment to achieve automatic control of the waste gas treatment process.

[0057] In a further embodiment, the spray tank of the humidification circulation module sprays water mist into the air through a nozzle for wet scrubbing. The nozzle is adjusted by a manual or automatic control system to control the relative humidity at 90% to 95% or more to meet the treatment requirements of different exhaust gases, ensure uniform distribution of water mist, and effectively cover the exhaust gas flow; and ensure accurate adjustment of the spraying amount through the flow control of the spray pump, and set the flow rate of the spray pump to 20m 3 / h, maintaining the exhaust gas humidity range. The circulating water tank is equipped with a heating device and a cooling device to heat or cool the spray liquid according to the cold or hot environment, accurately control the temperature of the spray liquid, and keep the exhaust gas temperature stable.

[0058] In a further embodiment, referring to Figure 2 The bio-box uses biodegradation to perform biological deodorization. The specific process is:

[0059] Gas-liquid diffusion: the odorous waste gas diffuses through the gas-liquid interface and transfers from the gas phase to the liquid phase. This process conforms to Henry's law.

[0060] Liquid-solid diffusion: the odorous waste gas dissolved in the liquid phase diffuses to the surface of the microbial membrane. The odor molecules in the odorous waste gas diffuse from the liquid phase to the biofilm of the biological filler and are adsorbed and absorbed by the microorganisms.

[0061] Biological oxidation: the microorganisms in the biofilm formed on the surface of the biological filler oxidize and decompose the adsorbed odor molecules. The microorganisms use the odor molecules as nutrients and decompose them into harmless or low-harm water and carbon dioxide through the metabolic process, and cause the diffusion and absorption of nutrients such as nitrogen or phosphorus and oxygen;

[0062] Microbial growth and inhibition: enzymes and antimicrobial peptides produced during microbial growth inhibit the growth of corrupt microorganisms and are used for preservation and to inhibit the generation of odors.

[0063] Through the above process, the metabolic activity of microorganisms is used to degrade malodorous gases and oxidize them into final products - sulfur-containing malodorous gases are decomposed into S, SO3 2- and SO4 2- ; Nitrogen-containing foul-smelling gases are decomposed into NH4 + 、NO3 - and NO2 - ; Malodorous gases without sulfur or nitrogen are decomposed into CO2 and H2O, thus achieving the purpose of odor purification. The main reaction equation is:

[0064]

[0065]

[0066]

[0067]

[0068] The malodorous gases in the exhaust gas require the participation of various microorganisms during the oxidation process, and different oxidation stages of the same malodorous gas require different microorganisms. During the oxidation process of sulfur-containing substances H2S, autotrophic sulfide-oxidizing bacteria will oxidize H2S into sulfate under certain conditions; during the oxidation process of organic sulfur methyl mercaptan, oxygen-conducting microorganisms first convert organic sulfur into H2S, and then autotrophic microorganisms convert it into sulfate; when the malodorous gas is ammonia, ammonia first dissolves in water, and then is converted into nitrates under aerobic conditions by nitrification of ammonia-oxidizing bacteria, nitrite bacteria and nitrifying bacteria. Under facultative anaerobic conditions, nitrate-reducing bacteria reduce nitrates to ammonia.

[0069] In a further embodiment, the biological deodorization module is a box-type structure, with a nutrient solution storage tank and automatic humidity control equipment at the bottom; the middle part is for biological organisms and fillers; the upper part is provided with an exhaust gas inlet, a qualified gas outlet and an automatic spray circulation system.

[0070] PLC is used to realize the automatic control of the system, specifically:

[0071] S1. Preset the range of target values ​​of spraying amount, humidification amount, temperature and flow rate in PLC;

[0072] S2, collect parameter data in real time through sensors installed in the exhaust gas deodorization system;

[0073] S3, PLC processes and analyzes the received sensor data to obtain the error between the current state and the set value. The specific calculation is:

[0074] The PID control algorithm is used to calculate the total control output, and the formula is:

[0075]

[0076] Where, e(t) is the deviation at time t, that is, the difference between the set value and the actual value, K p is the proportional gain, which determines the immediate response of the controller to the deviation, K i is the integral gain, which determines the controller's response to the accumulated deviation and is used to eliminate the steady-state error. d is the derivative gain, which determines the controller’s response to the rate of change of the error;

[0077] The calculation formula for spray volume control is:

[0078] Spray Pump Output=K s Humidity Error;

[0079] Among them, K s For the spray control gain, the humidity error is calculated based on the data from the humidity sensor, and the flow rate of the spray pump is adjusted;

[0080] The humidification control calculation formula is:

[0081] Humidifier Output = K h Humidity Error;

[0082] Among them, K h For humidification control gain, the humidity error is calculated based on the data from the humidity sensor, and the spraying amount of the humidifier is adjusted;

[0083] The temperature control calculation formula is:

[0084] Heater(CDoler)Output=K t Temperature Error;

[0085] Among them, Kt For temperature control gain, based on the data from the temperature sensor, the temperature error is calculated and the output of the heating or cooling device is adjusted;

[0086] The flow control calculation formula is:

[0087] Flow Control Valve Output=K f Flow Error;

[0088] Among them, K f For flow control gain, the flow error is calculated based on the data of the flow sensor, and the opening of the flow control valve is adjusted;

[0089] S4. According to the results of data processing, the PLC controls the operating status of the equipment and sends control signals to regulate the operation of the equipment to achieve automated control of the waste gas deodorization process.

[0090] In a further embodiment, referring to Figure 3 The present invention also provides a method for deodorizing waste gas, which is specifically:

[0091] The collected waste gas is pre-treated by an alkaline scrubber, using an alkaline solution such as sodium hydroxide or sodium carbonate solution, which is evenly sprayed into the waste gas stream through a spray system to neutralize the acidic pollutants such as hydrogen sulfide and sulfur dioxide in the waste gas, thereby reducing the acidic components in the waste gas;

[0092] The pre-treated waste gas is humidified by a humidifier to provide suitable humidity conditions for the growth of microorganisms;

[0093] The humidified waste gas passes through the biofilter, which is filled with biological carriers made of activated carbon, wood chips, soil or other porous materials. These carriers provide a surface for microorganisms to attach and grow. The microbial flora on the surface of the biological carrier captures the pollutants in the waste gas and multiplies rapidly in the biofilter;

[0094] The microbial flora decomposes the captured pollutants into carbon dioxide and other inorganic substances, and treats harmful substances in the exhaust gas;

[0095] The waste gas after biological filter treatment refers to GB14554-93, and the concentration is CO = 60mg / m 3 The following discharge is carried out to achieve the purpose of deodorization.

[0096] During the waste gas deodorization process, in order to ensure the efficient operation of the waste gas treatment system, the key parameters including the waste gas flow, temperature, humidity, pollutant concentration, etc. are monitored in real time through the automatic control system. The spray intensity of the alkali washing tower, the spray volume of the humidification device and the operating conditions of the biological filter can be adjusted in time to cope with the changes in the waste gas composition and flow, and improve the deodorization efficiency.

[0097] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A waste gas deodorization system, characterized in that: Including spray module, biological deodorization module, humidification circulation module, exhaust gas treatment module, control module; The spray module includes an alkaline scrubber, which processes acidic gases in the waste gas by neutralizing the waste gas with an alkaline absorbent, and pre-treats the input waste gas; The humidification circulation module includes a circulation water tank and a spray water tank, which are used to realize the recycling of the spray liquid and adjust the humidity and temperature of the exhaust gas; The biological deodorization module includes a pre-washing tank and a biological box. The pre-washing tank is connected to the humidification circulation module. The pre-treated waste gas enters the pre-washing tank and contacts with the spray water to remove large particles, some soluble gases and some organic matter in the waste gas through physical and chemical effects. The bio-box utilizes the biodegradation effect of microorganisms to adsorb and decompose organic matter in the waste gas to generate carbon dioxide and other inorganic substances for biological deodorization; The waste gas treatment module includes an acid washing tower, and the waste gas output from the bio-box undergoes a neutralization reaction with an acid solution to treat the alkaline gas in the waste gas to meet the waste gas emission standards; The control module uses PLC to control the operation of the waste gas treatment process equipment to achieve automatic control of the waste gas treatment process.

2. The exhaust gas deodorization system according to claim 1, characterized in that: The spray water tank sprays water mist into the air through a nozzle, and controls the spray volume by adjusting the opening of the nozzle and the flow of the spray pump to keep the exhaust gas humidity stable; the circulating water tank is equipped with a heating and cooling device to adjust the temperature of the spray liquid and keep the exhaust gas temperature stable.

3. The exhaust gas deodorization system according to claim 1, characterized in that: The bio-box utilizes biodegradation to perform biological deodorization, specifically: Gas-liquid diffusion: the odorous waste gas diffuses through the gas-liquid interface and transfers from the gas phase to the liquid phase; Liquid-solid diffusion: the odorous waste gas dissolved in the liquid phase diffuses to the surface of the microbial membrane. The odor molecules in the odorous waste gas diffuse from the liquid phase to the biofilm of the biological filler and are adsorbed and absorbed by the microorganisms. Biological oxidation: the microorganisms in the biofilm formed on the surface of the biological filler oxidize and decompose the adsorbed odor molecules. The microorganisms use the odor molecules as nutrients and decompose them into harmless or low-harm water and carbon dioxide through the metabolic process, and cause the diffusion and absorption of nutrients such as nitrogen or phosphorus and oxygen; Microbial growth and inhibition: enzymes and antimicrobial peptides produced during microbial growth inhibit the growth of corrupt microorganisms and are used for preservation and to inhibit the generation of odors.

4. The exhaust gas deodorization system according to claim 1, characterized in that: The biological deodorization module is a box-type structure, with a nutrient solution storage tank and automatic humidity control equipment at the bottom; the middle part is biological and filler; the upper part is provided with a waste gas inlet, a qualified gas outlet and a spray automatic circulation system.

5. The exhaust gas deodorization system according to claim 1, characterized in that: The PLC is specifically: S1. Preset the range of target values ​​of spraying amount, humidification amount, temperature and flow rate in PLC; S2, collect parameter data in real time through sensors installed in the exhaust gas deodorization system; S3, PLC processes and analyzes the received sensor data to obtain the error between the current state and the set value. The specific calculation is: The PID control algorithm is used to calculate the total control output, and the formula is: Among them, e(t) is the deviation at time t, that is, the difference between the set value and the actual value, K p is the proportional gain, which determines the immediate response of the controller to the deviation, K i is the integral gain, which determines the controller's response to the accumulated deviation and is used to eliminate the steady-state error. d is the derivative gain, which determines the controller’s response to the rate of change of the error; The calculation formula for spray volume control is: Spray Pump Output=K s ·Humidity Error; Among them, K s For the spray control gain, the humidity error is calculated based on the data from the humidity sensor, and the flow rate of the spray pump is adjusted; The humidification control calculation formula is: Humidifier Output=K h ·Humidity Error; Among them, K h For humidification control gain, the humidity error is calculated based on the data from the humidity sensor, and the spraying amount of the humidifier is adjusted; The temperature control calculation formula is: Heater(Cooler)Output=K t ·Temperature Error; Among them, K t For temperature control gain, based on the data from the temperature sensor, the temperature error is calculated and the output of the heating or cooling device is adjusted; The flow control calculation formula is: Flow Control Valve Output=K f ·Flow Error; Among them, K f For flow control gain, the flow error is calculated based on the data of the flow sensor, and the opening of the flow control valve is adjusted; S4. According to the results of data processing, the PLC controls the operating status of the equipment and sends control signals to regulate the operation of the equipment to achieve automated control of the waste gas deodorization process.

6. A method for deodorizing waste gas, characterized in that: Specifically: The collected waste gas is pre-treated through an alkali scrubber to reduce the acidic pollutant content in the waste gas; The pre-treated waste gas is humidified by a humidifier to meet the humidity conditions for microbial growth; The humidified waste gas passes through the biofilter, and the microbial flora on the surface of the biological carrier captures the pollutants in the waste gas and reproduces rapidly in the biofilter; The microbial flora decomposes the captured pollutants into carbon dioxide and other inorganic substances, and treats harmful substances in the exhaust gas; The waste gas treated by the biological filter is discharged to achieve the purpose of deodorization.

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