CN111793655A - A rapid start-up process and stable operation method for dry fermentation of chicken manure and corn stalks - Google Patents

Abstract

The invention relates to a rapid start-up process and a stable operation method for dry fermentation of chicken manure and corn stalks. The patent of the present invention uses chicken manure and corn stalks for dry anaerobic fermentation, and uses the pretreatment process of "mechanical pulverization + microbial decay" for dry corn stalks and mixes them with chicken manure for dry anaerobic fermentation. The quick-start process adopts dry start-up, uses special culture and domestication sludge for inoculation, and adjusts the initial pH stability of the reactor, improves the activity of methanogens, helps the rapid growth of methanogens, and reduces the alkali during the commissioning and start-up period. liquid addition. The method realizes rapid and stable start-up and stable operation of the dry anaerobic fermentation system.

Description

A rapid start-up process and stable operation method for dry fermentation of chicken manure and corn stalks

technical field

The invention relates to a rapid start-up process and a stable operation method for dry fermentation of chicken manure and corn stalks.

Background technique

As a major agricultural country, China is rich in corn stalk resources. In 2018, the main crop corn stalks in the country can collect 900 million tons of resources, of which corn stalks account for more than 1/3. It is reasonable to convert this part of resources into usable energy. important. As one of the important components of agriculture, animal husbandry is a major pillar industry of agricultural production and one of the main sources of farmers' income. At present, a large number of corn stalks and chicken manure in my country have not been effectively used, resulting in waste of resources, and anaerobic fermentation technology It is an effective means to realize the resource utilization of corn stalks. It is of great significance to solve the waste of corn stalks and generate methane gas and other renewable energy sources to alleviate the energy shortage in my country, promote the sustainable development of the social economy and improve the ecological environment. At present, anaerobic fermentation technologies all use a single material for anaerobic fermentation, and most of them are wet fermentation. However, in separate chicken manure fermentation, the product concentration after fermentation is low, energy consumption is large, and the carbon-nitrogen ratio is unbalanced, and the stability of the fermentation process is poor. . However, the high content of lignin in corn stalks makes it difficult to hydrolyze, resulting in long fermentation cycle and low biogas production efficiency when corn stalks are used as a single material for anaerobic fermentation, which cannot maximize the benefits of biogas projects. In addition, the output of sludge in urban sewage treatment plants is huge. Due to the high water content in the sludge, the calorific value after combustion is low, landfill occupies land resources, and it is easy to cause secondary pollution. At present, traditional anaerobic fermentation technology The method is to prevent the initial stage of the material dosage from being too high, the lack of methanogens leading to serious hydrolysis and acidification of the reactor, and the failure of start-up. Wet start-up is selected to ensure stable operation, and then the material dosage is continuously adjusted until the reactor is in a dry fermentation state. . However, in the initial stage of wet start-up, the dosage of materials is small, the total solid content in the reactor is low, the reaction period is long, and the operating efficiency of the reactor is low. In the traditional anaerobic fermentation process, the addition of sludge is only in the start-up stage and when the gas production efficiency is low, and it is not spread throughout the whole process, so it cannot maintain the acidification rate of acid-producing bacteria and the rate of volatile fatty acid utilization by methanogens to maintain dynamic balance, but sludge It has a high content of microorganisms, which can provide a sufficient amount of bacteria for the anaerobic fermentation process and properly supplement the alkalinity.

Therefore, the present invention proposes a stable dry anaerobic fermentation process with dry quick start on this basis.

SUMMARY OF THE INVENTION

The invention relates to a rapid start-up process and a stable operation method for dry fermentation of chicken manure and corn stalks. The corn stalk is pretreated by "mechanical pulverization + microbial decay" and then mixed with chicken manure according to the design and optimized ratio and then fermented. At the same time, the residual sludge of the sewage plant is subjected to a special cultivation and domestication process to adjust the pH of the anaerobic reactor and increase the The number of methanogens reduces the initial addition of lye, improves the stability of the startup speed, and effectively improves the gas production efficiency.

A rapid start-up process and stable operation method for dry fermentation of chicken manure and corn stalks,

1) Use dry corn stalks (usually mass moisture content of 6% to 12%) as an auxiliary material, and carry out the pretreatment process of "mechanical pulverization + microbial decay":

First, pulverize the corn stalks to ensure that the stalks above 60 mesh reach D80 (that is, the particle size is less than or equal to 60 mesh, and the straw particles reach more than 80%); Add 0.1%-0.3% of dry corn stalk mass of cellulase and 0.1%-0.3% of hemicellulase, and decompose under natural ventilation conditions for 3-5 days to obtain pretreated straw; The manure is adjusted according to the carbon-nitrogen ratio of 25-35:1 after mixing to obtain the mixed material to be fermented;

2) In the initial stage, dry start-up is adopted (the moisture content of the material inside the reactor is 70% to 85%), and the mixed straw and chicken manure need to be additionally equipped with domestication sludge that accounts for 20% to 30% of the total material mass. For inoculation, the material fills 75% to 80% of the total volume of the anaerobic reactor, and the stirring device is turned on for 5 to 10 minutes every 1 to 6 hours, and this process is maintained for 3 to 5 days;

3) When starting quickly, take 3 to 5 days as an adjustment period to gradually increase the daily feed amount, and the initial daily feed amount is 1% to 3% of the effective volume, and the concentration of methane in gas production is guaranteed to be above 35% and within the reactor. Under the condition that the pH value is above 6.5, the daily addition amount of the material is adjusted in steps, and the increase amount of each adjustment is 10% to 40% of the previous cycle of feed amount, until the system reaches full load operation (same daily feed amount It is 4% to 5% of the effective volume); the amount of feed and output should be consistent, so as to maintain the material filling volume in the reactor accounts for 75% to 80% of the total volume of the reactor (that is, to maintain the effective volume at 75% to 80% of the total volume of the reactor). 80%);

4) Stabilization stage: when the system reaches full load operation (that is, the daily feed amount is 4% to 5% of the effective volume, and the residence time is 20 to 25 days), the sludge can be stopped or reduced to be put into the anaerobic reactor material to domesticate the sludge. Proportioning amount (the reduction means that only the mixture of straw and chicken manure is used in the feed, or the mixed straw and chicken manure needs to be additionally equipped with domestication sludge that accounts for 5% to 30% of the mass of the feed material); normal operation of the system.

Use domesticated sludge to inoculate the initial stage (quick start) of reactor operation and use alkaline solution to supplement alkalinity and microbial biomass in the operation process (stable stage); The lye solution (the lye solution can be NaOH solution, etc., the concentration of the lye solution is 4.0-5.0mol/L) is used in a mass ratio of 1:1-2.

A methane concentration detector is arranged at the top of the anaerobic reactor and a pH value detector is arranged in the middle or at the bottom;

In one or both of the initial stage, fast start-up, and stable stage, when the methane concentration drops by 2% or the pH drops by more than 0.4, the domestic sludge (75% to 80% water content by mass) and alkali will be acclimated. The solution (the lye solution can be NaOH solution, etc., the concentration of the lye solution is 4.0～5.0mol/L) is used in a mass ratio of 1: 1～2, and the pH is adjusted to ensure that the pH is between 6.5～8.0;

Stir automatically after putting in, and check the pH twice after 3 to 5 hours. If it does not reach the specified range, continue to add lye to ensure that the pH in the fermentation broth is maintained between 6.5 and 8.0.

The anaerobic reactor adopts the zone temperature control method; due to the different heat requirements of each zone in the reactor, the shell of the anaerobic reactor is divided into 3 to 4 zones in sequence along the direction of material movement, and they are located in the middle of the anaerobic reactor. And/or the bottom is provided with a temperature sensor and a heating device (such as an electric heating element or a heating water pipe or a heating water jacket), through the real-time measurement of the temperature sensor connected with the temperature controller signal, by adjusting the temperature controller and the external power supply. The power of the heating device or the flow of hot water is controlled by adjusting the solenoid valve on the heating water pipeline connected to the temperature controller, so that the overall temperature of the reactor is at 37±2°C to ensure the stable operation of the reactor.

The reactor is fed in the form of a bell-free (Figure 3). A bell-free is installed at the feed port at the upper or top of the anaerobic reactor. The upper and lower ends of the bell are equipped with inlet and outlet valves. Equipped with heating devices (such as one or more of hot water coils, heat exchangers, electric heaters, etc.) and biogas stripping inlet and outlet; biogas stripping inlet and anaerobic reactor top biogas outlet or external nitrogen The gas source is connected, and the heating device is used to preheat the feed to 37±2°C, so as to prevent the cold material from entering the system, which will cause the local temperature to change too much and reduce the microbial activity; The material is stripped at the inlet and outlet to prevent the oxygen in the feed from entering the anaerobic reactor. While reducing the safety risk, it ensures that the reactor maintains a stable environment without oxygen and ensures the stable operation of the reactor.

The preparation process of domestication sludge: firstly, the sludge and the mixed material to be fermented (chicken manure and pretreated corn stover) are mixed in a mass ratio of 1:1 to 4 in a separate tank for domestication, and at the same time, according to the amount of the mixture, according to 10 Add lye solution at a ratio of ~40mg/L (NaOH solution can be used for lye solution, the concentration of lye solution is 4.0-5.0mol/L), adjust the pH to 6.5-8.0, and control the temperature of sludge domestication to maintain at 37±2℃. Measure the pH to ensure that the pH in the sludge is always in the range of 6.5 to 8.0 suitable for the survival of methanogens, fully stir 2 to 5 times a day, and replenish the fermented mixture of equal quality once a week, and it can be used after one week of domestication;

The source of sludge is residual activated sludge from municipal sewage plants, with a mass moisture content of 75-80%.

In the start of the mixed anaerobic fermentation of chicken manure and corn stalk, the single fermentation has serious disadvantages such as imbalance of carbon and nitrogen nutrient ratio, which is not conducive to the application of biogas projects. Therefore, the present invention utilizes its respective advantages to adjust the chicken manure and corn stalks according to the carbon-nitrogen ratio of 25-35:1, which can maintain the activity of acid-producing bacteria and methanogenic bacteria in the anaerobic reactor and improve the efficiency of biogas engineering.

Cellulose and hemicellulose in corn stalks are not conducive to the absorption and utilization of nutrients in corn stalks by microorganisms. Therefore, the method of “mechanical pulverization + microbial decay” is used to pre-treat corn stalks to improve the utilization rate of nutrients.

Provide a new start-up method. On the basis of using mixed materials, dry step-type start-up can be selected, which can greatly shorten the fermentation period and improve the economy.

In the reactor feeding mode, a bellless feeding form is adopted, and a heating device and an oxygen stripping device are provided to ensure that the internal temperature of the reactor and the oxygen concentration are stable.

Set the intelligent detection system to monitor the methane concentration and pH in the system and link it with the alkali addition system.

Select specially acclimated sludge to replace part of lye addition, maintain the pH of the fermentation system and provide additional methanogens, so that the anaerobic reactor can run stably.

Activated sludge: It is a general term for microbial groups and the organic and inorganic substances they are attached to. The microbial groups mainly include bacteria, protozoa and algae. Sludge in the oxygen tank.

The rapid start-up process of the invention adopts dry start-up, uses special cultured and domesticated sludge for inoculation, adjusts the initial pH stability of the reactor, improves the activity of methanogens, helps to increase the rapid reproduction of methanogens, and reduces the commissioning and start-up period. of lye added. The method realizes rapid and stable start-up and stable operation of the dry anaerobic fermentation system in the later stage.

Description of drawings

Figure 1 The whole process of material addition;

Figure 2. The whole system process of chicken manure and corn stalks quick start operation;

Fig. 3 is a schematic diagram of the structure without a bell; wherein, 1, the feed valve without the bell, 2, the discharge valve without the bell, 3, the heating jacket (or interlayer) of the water bath without the bell, 4, the blow-off valve, 5. Blow off the intake valve, 6. The heating system feeds water, 7. The heating system returns water;

Detailed ways

The object of the present invention is achieved in this way:

As shown in Figure 2, the corn stalks used for fermentation are crushed to ensure that the 60 mesh stalks reach D80, and the sludge is taken from the sewage treatment plant (sludge comes from the remaining biologically activated sludge after dehydration, sludge thickening tank or anaerobic sludge). digester). Before the sludge is used, it needs to be mixed with the mixed material to be fermented (fresh chicken manure + pretreated corn stalks) in a mass ratio of 1:1 to 4 in a separate tank for domestication. Control the sludge acclimation temperature to maintain at 37±2℃, measure the pH daily to ensure that the pH in the sludge is always in the range of 6.5 to 8.0 suitable for the survival of methanogens, fully stir three times a day, and replenish the same quality of fermented water once a week. Mix the ingredients and use them after acclimation for a week. The mixture of chicken manure and corn stalks needs to add part of lye and acclimated sludge daily according to pH and methane concentration changes in the initial stage and start-up stage to ensure pH stability and sufficient number of microorganisms. The whole cycle of the test adopts the same amount of feeding and the same amount of discharging. Due to the large amount of material added and discharged in the stable stage, in order to prevent the loss of microorganisms in the fermentation reactor, the method of supplementing domesticated sludge is adopted, which can not only maintain high biogas production efficiency, but also increase the efficiency of biogas production. The efficiency of decomposition and utilization of large input materials. The materials discharged from the initial stage, start-up stage and stabilization stage are all subject to secondary aerobic composting. In order to ensure the rapid and stable operation of the anaerobic fermentation process, an intelligent detection system is set up. In order to ensure the pH stability in the anaerobic reactor, a real-time pH online detection instrument is set up. Through the control system and regulation system, when the detection pH is not between 6.5 and 8.0 When , the amount of lye and sludge after domestication will be automatically calculated to ensure pH stability. The zone temperature sensor set in the anaerobic reactor feeds back the temperature in different intervals and adjusts the power of the heating device to ensure that the overall temperature of the anaerobic reactor is 37±2℃. The biogas collection site adopts biogas treatment device (dehydration and desulfurization, etc.) to separate H ₂ S and moisture in the gas to ensure high-purity CH ₄ . The change of methane concentration will be fed back to the central control system in real time, and the domestication will be adjusted appropriately according to the change of methane concentration. The amount of sludge put in.

Example

1. A special corn stover pretreatment method. Because corn stover contains a lot of lignin, cellulose and hemicellulose, etc., it seriously affects the efficiency of anaerobic fermentation in the utilization of biogas projects. Therefore, the present invention selects the "physical + biochemical" combined pretreatment method of "mechanical pulverization + microbial decay". The specific operation is: first use physical treatment technology to pulverize the air-dried corn stalk (usually the mass moisture content is 6% to 12%), so that the 60-mesh stalk reaches D80, so as to ensure that the lignin, cellulose and hemicellulose in the corn stalk are treated for the first time. At the same time, the specific surface area of corn stalk is increased, which is convenient for the decomposition and utilization of acid-producing bacteria and methanogenic bacteria. Subsequently, the corn stalks crushed below 60 mesh are pretreated by microbial decay technology. The specific method is to adjust the crushed corn stalks to a mass moisture content of 75% to 80%, and according to the specific method used in the biogas project. The amount of corn stalks is added with 0.1% to 0.3% of the dry corn stalk mass of cellulase (here 0.2%) and hemicellulase (here 0.2%) and stacking, and the stacking is controlled to maintain at 40 ° C ~ Between 60 °C, the molecular structure of the cell wall is effectively destroyed, and the precipitation of intracellular solubles in corn stover is accelerated. It can be used after stacking for 3 to 5 days (here, 4 days) under natural ventilation.

Comparison of data before and after air-dried straw pretreatment

It can be seen from the analysis of the data that after pretreatment, the total sugar yield can reach 11.75g/100g DM, which improves the utilization rate of corn stalks, and reduces the proportion of stalks added in the project to 10% to 20%. It reduces the operating cost and reduces the expansion rate of the material.

2. Sludge domestication and a method for periodically replenishing microorganisms with domesticated sludge.

The traditional activated sludge domestication does not add alkali solution to maintain the optimum pH of methanogens, resulting in a long domestication period and slow reproduction of methanogens, and the pH in the dry anaerobic reactor may continue to decrease with the addition of materials. Microorganisms will also be lost along with the discharge, resulting in reduced reactor efficiency and unstable gas production. Therefore, the present invention firstly mixes the sludge with the mixed material to be fermented (fresh chicken manure + pretreated corn stover) in a mass ratio of 1:1 to 4 (here, 1:1) in a separate tank for domestication (sewage). The source of mud is the residual activated sludge of municipal sewage plants, with a mass moisture content of 75-80%.), at the same time, according to the amount of the mixture, lye is added in the proportion of 10-40mg/L. The lye solution can be NaOH solution, etc. 4.0～5.0mol/L (here, 4.5mol/L), adjust the pH to 6.5～8.0, control the sludge acclimation temperature to maintain at 37±2℃, measure the pH every day to ensure that the pH in the sludge is always suitable for methane production. Within the range of 6.5 to 8.0 for the survival of bacteria, fully stir 2 to 5 times a day, and replenish the fermented mixture of equal quality once a week, and it can be used after one week of domestication. To maintain the maximum activity of methanogens, it is used for the rapid start-up of the mixed fermentation of chicken manure and corn stover, and the entire sludge acclimation process is maintained until the end of the start-up. During rapid start-up, the mixed materials need to be additionally equipped with domesticated sludge with a mass ratio of 20% to 30% for inoculation, and the domesticated sludge is continuously supplemented throughout the start-up cycle. 4% to 5% of the effective volume, and the material residence time is 20 to 25d) to stop or reduce the proportion of domesticated sludge, so that the anaerobic reactor can be started quickly in the early stage and stable in the later stage.

3. As shown in Figure 1, the corn stalk is first crushed to below 5cm by a cutter, and then crushed to below 60 mesh by a grinder to ensure that the corn stalk below 60 mesh reaches D80, and then the crushed corn stalk is adjusted to the mass moisture content. To 80%, add 0.2% cellulase and 0.2% hemicellulase by mass of corn stalk, and carry out 5 days of decay under natural ventilation conditions to obtain pretreated stalks. After microbial decay, the pretreatment is completed. It is mixed with the pretreated straw in proportion and then inoculated with 30% of domesticated sludge. For a 30L anaerobic fermenter, a total of 24L of 80% moisture content mixture needs to be put in, and the fermented material accounts for 80% of the total volume of the fermenter. , to prevent clogging of the reactor due to fermentation expansion, and turn on the stirring device for 5 minutes every 1 to 6 hours. The inner wall of the side wall of the material area of the anaerobic reactor is equally divided into 4 areas along the direction of material movement, using the installed zone temperature measurement and temperature control system (the temperature sensor connected to the temperature controller signal, and the temperature controller connected to the external power supply The electric heating tube), control the overall fermentation temperature 37 ± 2 ℃, this process reaches the level of dry fermentation in the initial stage, and the initial stage is maintained for 5 days. Continue to add lye and alkali treated and domesticated sludge during the rapid start-up stage. When the methane concentration drops by 2% or the pH drops more than 0.4, the domesticated sludge and The pH of the lye is adjusted (here, the concentration of lye is 4.5mol/L NaOH solution, and the mass ratio of sludge and lye is 1:1), and the pH of the reactor is maintained between 6.5 and 8.0 while increasing a sufficient amount of microorganisms. And reduce the usage of lye (30% here), automatically stir after lye or sludge is put in, and check the pH twice after 4 hours, if it does not reach the specified range, continue to add lye to ensure fermentation The pH of the solution was maintained between 6.5 and 8.0. Subsequently, 0.5kg (effective volume 2.1%) of the mixed material was added to the reactor every day, and the daily addition amount of the material was adjusted stepwise under the conditions that the gas-producing methane concentration was above 35% and the pH value in the reactor was above 6.5. Take 5 days as an adjustment cycle to gradually increase the daily feeding amount, and the increase amount for each adjustment is 20% of the feeding amount in the previous cycle. When this example reaches full load operation, 4 step adjustment cycles (same daily feeding amount) have passed. The material volume reaches 4% of the effective volume, and the material residence time is 20-25d at this time. Using this method to quickly start the dry anaerobic reactor can shorten the start-up and commissioning period from the original 60-90 days to 20-30 days. This time it was 25 days (5 days in the initial stage, 20 days for quick start), and then in order to maintain the stable operation of the reactor, an additional 10% of the feed quality of domesticated sludge was placed in the feed of the anaerobic reactor, which could Maintain the stable operation of the anaerobic reactor in the later stage.

main indicators traditional way Quick Start dry anaerobic fermentation 30～60d 1d startup cycle 60～90d 20～30d The frequency of adding liquid alkali during the start-up period 1～3d/time 5～10d/time

The biogas produced by the anaerobic reactor is monitored for instantaneous flow and cumulative flow by a gas flow meter, and then processed by a dehydration and desulfurization device (the dehydration device used here is an adsorption-type dehydration tank. The desulfurization device is a packing dry desulfurization device), and finally obtained purer methane.

The anaerobic reactor also includes: an intelligent online detection and adjustment system for pH and methane concentration. In order to ensure that the activity of methanogens in the anaerobic reactor is in a good and stable state, an intelligent detection system for methane concentration and pH is set up in the reactor. 10～40mg/L of domesticated sludge and lye solution (the lye solution is prepared by 4.5mol/L NaOH solution, the mass ratio of sludge and lye solution is 1:1). If the pH does not reach the specified range, continue to add lye to ensure that the pH in the fermentation broth is maintained between 6.5 and 8.0, to ensure that the biogas project is in a high-efficiency state, and to maintain the number of bacteria and alkalinity.

The anaerobic reactor also includes: an anaerobic reactor zone temperature online detection and adjustment system. Since the heat demand of each area in the reactor is different, the zone temperature control method is adopted, and the material area on the inner wall of the anaerobic reactor side wall is divided into 4 areas on average along the material movement direction, and temperature sensors and heating devices are installed in each area to control The system uses the real-time measurement of the installed zone temperature measurement temperature sensor to adjust the power or hot water flow of the heating device corresponding to the zone to ensure that the overall temperature of the reactor is 37±2°C.

A set of central control system and intelligent regulation system, install methane concentration detection probes in the gas chamber at the top of the anaerobic reactor, and install temperature detection probes and pH detection probes in the material area on the inner wall of the anaerobic reactor along the direction of material movement in 4 areas. Value detection probe, the indicators detected online by the above-installed detection probes are in the form of electrical signals, and the electrical signals are transmitted to the PLC through the signal line to convert into digital signals, and then the digital signals are transmitted to the central computer for real-time display and operation. By setting parameters on the central computer, the value that does not meet the set range will be controlled by the PLC intelligent control system to start and stop the heating device and the alkali adding device, so as to realize the automatic adjustment of temperature and pH.

A method for reusing anaerobic fermentation output materials. Since anaerobic fermentation cannot completely degrade organic matter, the output material still contains a large amount of organic matter components. Further composting of the output material can realize the secondary degradation and utilization of organic matter. , convert the remaining organic matter of anaerobic fermentation into stable humus, and apply it to farmland to increase soil fertilizer efficiency, and truly realize the reduction, resource utilization and harmlessness of agricultural waste.

The anaerobic reactor also includes: a bellless feeding process with preheating and stripping functions (as shown in Figure 3). In order to avoid the temperature fluctuation of the fermentation broth in the reactor due to the addition of the initial material that does not reach the specified temperature into the reactor, the activity of acid-producing bacteria and methanogenic bacteria will be affected. When feeding, open the feed valve 1 without a bell (Fig. 3), close the feed valve 1 without a bell after the material is put in, and blow out the gas outlet valve 4 to connect the atmosphere with the bell-free tank, blowing off the feed valve. The gas valve 5 connects the stripping gas source with the tank without the material bell, and the material is stripped for 1 min by opening the valve 4 and valve 5. The stripping gas adopts the biogas generated by the reactor (can also use external canned nitrogen or other Inert gas), remove the oxygen carried by itself when the material is added, maintain a stable oxygen-free environment, and close valve 4 and valve 5 after stripping. When blowing off, it is necessary to prevent the material from splashing due to the low moisture content of the material, blocking the sampling port and the air outlet, etc. At the same time, through the heating system inlet 6 and the heating system return water 7, the circulating hot water is passed through the bellless water bath heating jacket 3 to pre-heat the material inside the bellless, and the temperature setting is consistent with the set temperature of the reactor, which is 37±2 ℃, after the material processing is completed, the bellless discharge valve 2 is opened, and the material inside the bellless enters the interior of the anaerobic reactor connected at the lower part under the action of gravity.

Data comparison before and after preheating and stripping

main indicators unprocessed processed temperature 18℃～25℃ 37±2℃ oxygen content 10～21% 1% or less Reactor temperature fluctuations Within -3℃ ±0.5℃ Reactor gas production inhibition time 30～60min 0～10min

The patent of the present invention adopts chicken manure and corn stalk for dry anaerobic fermentation, and adopts the pretreatment process of "mechanical pulverization + microbial decay" to dry corn stalk and mixes it with chicken manure for dry anaerobic fermentation. The quick-start process adopts dry start-up, uses special culture and domestication sludge for inoculation, and adjusts the initial pH stability of the reactor, improves the activity of methanogens, helps the rapid growth of methanogens, and reduces the alkali during the commissioning and start-up period. liquid addition.

Claims (6)

1. a rapid start-up process and stable operation method for dry fermentation of chicken manure and corn stalks, it is characterized in that: 1) Using dry corn stalks (usually the mass moisture content of 6% to 12%) as an auxiliary material, the pretreatment process of "mechanical pulverization + microbial decay" is carried out: First, pulverize the corn stalks to ensure that the stalks above 60 mesh reach D80 (that is, the particle size is less than or equal to 60 mesh, and the straw particles reach more than 80%); Add 0.1%-0.3% of dry corn stalk mass of cellulase and 0.1%-0.3% of hemicellulase, and decompose under natural ventilation conditions for 3-5 days to obtain pretreated straw; The manure is adjusted according to the carbon-nitrogen ratio of 25 to 35:1 after mixing to obtain the mixed material to be fermented; 2) In the initial stage, dry start-up is adopted (the moisture content of the material inside the reactor is 70% to 85%), and the mixed straw and chicken manure need to be additionally equipped with domestication sludge that accounts for 20% to 30% of the total material mass. For inoculation, the material fills 75% to 80% of the total volume of the anaerobic reactor, and the stirring device is turned on for 5 to 10 minutes every 1 to 6 hours, and this process is maintained for 3 to 5 days; 3) When starting quickly, take 3 to 5 days as an adjustment period to gradually increase the daily feed amount, and the initial daily feed amount is 1% to 3% of the effective volume, and the concentration of methane in gas production is guaranteed to be above 35% and within the reactor. Under the condition that the pH value is above 6.5, the daily addition amount of the material is adjusted in steps, and the increase amount of each adjustment is 10% to 40% of the previous cycle of feed amount, until the system reaches full load operation (same daily feed amount It is 4% to 5% of the effective volume); the amount of feed and output should be consistent, so as to maintain the material filling volume in the reactor accounts for 75% to 80% of the total volume of the reactor (that is, to maintain the effective volume at 75% to 80% of the total volume of the reactor). 80%); 4) Stabilization stage: when the system reaches full load operation (that is, the daily feed amount is 4% to 5% of the effective volume, and the residence time is 20 to 25 days), the sludge can be stopped or reduced to be put into the anaerobic reactor material to domesticate the sludge. Proportion amount (the reduction means that only the mixture of straw and chicken manure is used in the feed or the mixed straw and chicken manure needs to be additionally equipped with domestication sludge that accounts for 5% to 30% of the mass of the feed material); normal operation of the system. 2. method according to claim 1, is characterized in that: Use domesticated sludge to inoculate the initial stage (quick start) of reactor operation and use alkaline solution to supplement alkalinity and microbial biomass in the operation process (stable stage); The lye solution (the lye solution can be NaOH solution, etc., the concentration of the lye solution is 4.0-5.0mol/L) is used in a mass ratio of 1:1-2. 3. method according to claim 1, is characterized in that: A methane concentration detector is arranged at the top of the anaerobic reactor and a pH value detector is arranged in the middle or at the bottom; In one or both processes of the initial stage, the rapid start-up and the stable stage, when the methane concentration drops by 2% or the pH drops by more than 0.4, the domesticated sludge (with a mass moisture content of 75% to 80%) and alkali The liquid (the lye solution can be NaOH solution, etc., the concentration of the lye solution is 4.0-5.0mol/L) is used in a mass ratio of 1:1-2, and the pH is adjusted to ensure that the pH is between 6.5-8.0; After putting in, it is automatically stirred, and the pH is checked twice after 3 to 5 hours. If it does not reach the specified range, continue to add lye to ensure that the pH in the fermentation broth is maintained between 6.5 and 8.0. 4. method according to claim 1, is characterized in that: The anaerobic reactor adopts the zone temperature control method; due to the different heat requirements of each zone in the reactor, the shell of the anaerobic reactor is divided into 3 to 4 zones in sequence along the material movement direction, and they are located in the middle of the anaerobic reactor. And/or the bottom is provided with a temperature sensor and a heating device (such as an electric heating element or a heating water pipe or a heating water jacket), through the real-time measurement of the temperature sensor connected with the temperature controller signal, by adjusting the temperature controller and the external power supply. The power of the heating device or the flow of hot water is controlled by adjusting the solenoid valve on the heating water pipeline connected to the temperature controller, so that the overall temperature of the reactor is at 37±2°C to ensure the stable operation of the reactor. 5. method according to claim 1, is characterized in that: The reactor is fed in the form of a bell-free (Figure 3). A bell-free is installed at the feed port at the upper or top of the anaerobic reactor. The upper and lower ends of the bell are equipped with inlet and outlet valves. Equipped with heating devices (such as one or more of hot water coils, heat exchangers, electric heaters, etc.) and biogas stripping inlet and outlet; biogas stripping inlet and anaerobic reactor top biogas outlet or external nitrogen The gas source is connected, and the heating device is used to preheat the feed to 37±2°C, so as to prevent the cold material from entering the system, which will cause the local temperature to change too much and reduce the microbial activity; The material is stripped at the inlet and outlet to prevent the oxygen in the feed from entering the anaerobic reactor. While reducing the safety risk, it ensures that the reactor maintains a stable environment without oxygen and ensures the stable operation of the reactor. 6. The method according to claim 1, 2 or 3, characterized in that: The preparation process of domestication sludge: firstly, the sludge and the mixed material to be fermented (chicken manure and pretreated corn stover) are mixed in a mass ratio of 1:1 to 4 in a separate tank for domestication, and at the same time, according to the amount of the mixture, according to 10 Add lye solution at a ratio of ~40mg/L (NaOH solution can be used for lye solution, the concentration of lye solution is 4.0-5.0mol/L), adjust the pH to 6.5-8.0, and control the temperature of sludge domestication to maintain at 37±2℃. Measure the pH to ensure that the pH in the sludge is always in the range of 6.5 to 8.0 suitable for the survival of methanogens, fully stir 2 to 5 times a day, and replenish the fermented mixture of equal quality once a week, and it can be used after one week of domestication; The source of sludge is residual activated sludge from municipal sewage plants, with a mass moisture content of 75-80%.

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