JP2009244220A - Ammonia concentration monitoring device, and fodder manufacturing system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ammonia concentration monitoring device for monitoring increase/decrease variation in ammonia concentration in gas, and to provide a fodder manufacturing system and method using the ammonia concentration monitoring device. <P>SOLUTION: The ammonia concentration monitoring device for monitoring the variation in ammonia concentration in the gas includes a glass film object, an internal liquid put into the glass film object, a first electrode in contact with the internal liquid, a liquid film forming section disposed on the surface of the outside of the glass film object, a second electrode in contact with the liquid film formed by the liquid film forming section, and a detection section for determining the physical quantity corresponding to the ammonia concentration in the gas based on the voltage difference between the first electrode and second electrode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ammonia concentration monitoring device capable of monitoring a change in ammonia concentration in a gas, and a feed production system and method using the ammonia concentration monitoring device.

  As processing of organic waste such as livestock waste and garbage, there is a fermentation process using methane fermentation bacteria. A large amount of ammonia nitrogen is contained in the fermentation broth which is the residue after the fermentation treatment. Therefore, as one of the effective utilization techniques of ammonia, air is brought into contact with the fermentation broth to recover ammonia, a gas containing the recovered ammonia is sent into the ammonia treatment tank, and the grain leaves and stems in the treatment tank There is known a technique for producing a feed with high added value by improving the digestibility, nutritional value, and livestock preference of feed by applying ammonia treatment to (for example, moss and semi-dry grass). (For example, patent document 1).

The quality of feed obtained by this feed production technology is affected by the ammonia concentration in the gas containing ammonia supplied to the ammonia treatment tank. Therefore, it is necessary to measure the ammonia concentration.
JP-A-2005-13909

  However, the measurement method of ammonia concentration in a gas conventionally performed is limited due to the property of ammonia adsorption. At present, a sample is collected and transported to a separate analysis center for analysis. Or it is a grade which measures with an ammonia concentration detection tube. The former takes several days to obtain a measurement result, and the latter also takes several hours, and the ammonia concentration cannot be detected in real time. Furthermore, since neither can monitor the change in the ammonia concentration, it was impossible to respond in real time to the change in the ammonia concentration. Therefore, there has been a problem that the quality of the feed varies.

  An object of the present invention is to provide an ammonia concentration monitoring device capable of monitoring an increase / decrease change in ammonia concentration in a gas, and a feed production system and method using the ammonia concentration monitoring device.

  In order to achieve the above object, a first aspect of the present invention is an ammonia concentration monitoring device for monitoring a change in ammonia concentration in a gas, comprising a glass film body and an internal liquid contained in the glass film body. A first electrode in contact with the internal liquid, a liquid film forming part provided on the outer surface of the glass film body, a second electrode in contact with the liquid film formed by the liquid film forming part, and a gas And a detection unit that obtains a physical quantity corresponding to the ammonia concentration in the medium based on a voltage difference between the first electrode and the second electrode.

  Here, the liquid film forming portion means a water retention structure capable of forming a film of liquid such as water in the portion. Typically, water-retaining sheets such as cloth, paper, and porous bodies are exemplified. In addition, you may enable it to form a liquid film with the structure of the outer surface itself of a glass film.

  When water contained in the gas adheres to the liquid film forming part or when a liquid film of water is formed by spraying water or the like, ammonia in the gas dissolves in the liquid film. If the ammonia concentration is high, it dissolves much, and if the ammonia concentration is low, it dissolves little. The ammonia concentration dissolved in the liquid film changes up and down until it reaches equilibrium with the ammonia concentration in the gas. Therefore, the ammonia concentration in the liquid film corresponds to the ammonia concentration in the gas.

If a large amount of ammonia is dissolved in the liquid film, the physical quantity of the liquid film, such as the pH value, becomes large. Hereinafter, in order to simplify the explanation, the physical quantity is fixed to the pH value. Of course, the pH value is not limited. For example, the voltage difference value may be used as it is. If the ammonia concentration increases or decreases, the pH value also increases or decreases. For example, the pH value, which is a physical quantity corresponding to the ammonia concentration in the gas, can be detected by the detection unit based on the voltage difference between the first electrode and the second electrode. Therefore, prepare several kinds of gas whose ammonia concentration in the gas is determined in advance with a detector tube, etc., bring the gas into contact with the liquid film, and measure the pH value in the liquid film in an equilibrium state. Thus, the ammonia concentration in the corresponding gas can be grasped by measuring the pH value of the liquid film by previously obtaining the relationship between them and preparing a calibration curve. The increase or decrease of the ammonia concentration in the corresponding gas can be grasped in real time by increasing or decreasing the pH value of the liquid film.
That is, according to this aspect, the change in the ammonia concentration in the gas can be monitored by measuring the increase or decrease in the physical quantity such as the pH value of the liquid film in which ammonia is dissolved.

  According to a second aspect of the present invention, in the ammonia concentration monitoring device according to the first aspect, the detection unit is configured to obtain a pH value of the liquid film as a physical quantity corresponding to the ammonia concentration in the gas. It is characterized by being. As described, the change in the ammonia concentration in the gas can be monitored by measuring the change in the pH value of the liquid film.

  According to a third aspect of the present invention, in the ammonia concentration monitoring apparatus according to the first or second aspect, the detection unit includes a display unit that displays a value of the ammonia concentration corresponding to the obtained physical quantity. It is characterized by being.

  According to this aspect, since the user can grasp the increase / decrease change in the ammonia concentration, an appropriate measure can be taken thereafter.

  The feed production system according to the fourth aspect of the present invention includes a gas supply unit, a fermentation liquid produced by subjecting an organic waste to methane fermentation, ammonia produced by fermentation, a gas sent from the gas supply unit, and the An ammonia recovery tower that recovers in the gas by gas-liquid contact with the fermentation broth, an ammonia treatment tank that contacts the ammonia recovered in the gas with the ammonia recovery tower with the feed material, and an outlet of the ammonia recovery tower A feed production system comprising a first ammonia concentration monitoring device provided in a gas feed line between the ammonia treatment tank and the ammonia treatment tank, wherein the first ammonia concentration monitoring device is the first to the first embodiment. The ammonia concentration monitoring device according to any one of the three embodiments is characterized in that

  According to this aspect, the ammonia concentration in the gas recovered by gas-liquid contact in the ammonia recovery tower is monitored by the ammonia concentration monitoring device, so that the change in concentration of the recovered ammonia can be grasped in real time. Can do. Therefore, when the ammonia concentration decreases or increases excessively, the ammonia concentration in the gas is adjusted by adjusting the amounts of the gas and the fermentation broth in the gas-liquid contact in a direction to correct the change. It can be kept within a certain range. Thereby, the feed with high added value which improved the digestibility as a feed, a nutritional value, and the preference of livestock can be manufactured without quality variation.

  According to a fifth aspect of the present invention, in the feed production system according to the fourth aspect, a gas return line is provided between an outlet of the ammonia treatment tank and the gas supply unit, and the gas feed line and the gas return line are provided. A gas circulation line is configured, and a second ammonia concentration monitor device is provided in the gas return line. The second ammonia concentration monitor device is the ammonia concentration according to any one of the first to third embodiments. It is a monitor device.

  According to this aspect, the recovered ammonia-containing gas is sent to the ammonia treatment tank through the gas feed line, where ammonia is consumed for making feed in the ammonia treatment tank, and the ammonia concentration is reduced (consumed to almost zero). Gas) is returned to the gas supply section through the gas return line and circulated. The ammonia concentration before entering the ammonia treatment tank is monitored by the first ammonia concentration monitor device, and the ammonia concentration after leaving the ammonia treatment tank is monitored by the second ammonia concentration monitor device. .

  Therefore, since the increase / decrease change of the consumption amount of ammonia in the ammonia treatment tank can be detected in real time, it is possible to take subsequent measures in consideration of the information on the consumption amount of ammonia.

  According to a sixth aspect of the present invention, in the feed production system according to the fifth aspect, the fermentation which receives the detection results of the first ammonia concentration monitoring device and the second ammonia concentration monitoring device and sends the results to the ammonia recovery tower. A control unit for adjusting the amount of liquid and the amount of gas, and a control unit for controlling the operation condition setting unit of the ammonia treatment tank is provided.

  According to this aspect, the ammonia concentration in the gas sent to the ammonia treatment tank can be automatically maintained within a certain range, and the operating conditions such as the temperature of the ammonia treatment tank can be automatically optimized. can do.

In the feed production method according to the seventh aspect of the present invention, ammonia produced by fermentation from the fermentation liquid after methane fermentation is brought into the gas by gas-liquid contact between the gas sent from the gas supply unit and the fermentation liquid. An ammonia recovery step to be recovered; an ammonia treatment step in which ammonia recovered in the gas in the ammonia recovery step is brought into contact with a feed material; and an increase or decrease in the concentration of ammonia in the gas sent to the ammonia treatment step is detected. And a step of controlling the amount of fermentation liquid and the amount of gas sent to the ammonia recovery tower based on the detection result.
According to this aspect, the ammonia concentration in the gas sent to the ammonia treatment tank can be automatically maintained within a certain range.

  According to the present invention, an increase / decrease change in the ammonia concentration in the gas can be monitored. Therefore, the ammonia concentration in the gas recovered by gas-liquid contact in the ammonia recovery tower is monitored by the ammonia concentration monitoring device, so that the change in concentration of the recovered ammonia can be grasped in real time. Therefore, when the ammonia concentration decreases or increases excessively, the ammonia concentration in the gas is adjusted by adjusting the amounts of the gas and the fermentation broth in the gas-liquid contact in a direction to correct the change. It can be kept within a certain range.

  First, an overview of a feed production system and a feed production method according to the present invention will be described.

[Organic waste]
In the present invention, organic waste includes, for example, livestock waste, green farm waste, wastewater treatment sludge, and the like. Examples of livestock waste include livestock manure, carcass and / or processed products thereof. More specifically, livestock carcasses such as cattle, sheep, goats and chickens, and bones separated therefrom. In addition to meat, fat, internal organs, blood, brain, eyeballs, skin, hoofs, horns, etc., crushed material of bones, meat, etc. of livestock carcasses represented by meat and bone meal, meat meal, bone meal, blood meal In addition, a dried product obtained by drying blood or the like is also included. In addition to household garbage, green agricultural waste includes agricultural and industrial waste, food processing waste, etc. as industrial waste.

[Fermentation process]
Ultra-high temperature methane fermentation (methane fermentation at 60 ° C or higher)
Prior to ultra-high temperature methane fermentation, depending on the state of the organic waste as a raw material, a crushing / sorting step and removal of contaminants can be carried out as a pretreatment as necessary. The crushing / sorting step can be performed by, for example, fractionating crushing as shown below, or crushing the entire amount.

  In the case of fractional crushing, a crushing / separating machine is used to collect a portion of the organic waste that can be easily crushed as a slurry together with the liquid. On the other hand, parts that are difficult to crush are collected separately as a lump. The water content of the slurry is 70 to 90% by weight, and the water content of the lump is about 40 to 60% by weight. The crushing / separating machine crushes organic solids by a shearing force and a pulling force, and a two-axis type or a three-axis type cutter can be used. When animal carcasses such as cattle are used as raw materials, it is preferable to crush the triaxial type from the viewpoint of crushing fineness and uniformity.

  The mixed plastics and sheets to be sorted and removed can be removed by mesh sorting, wind sorting (wind sorting), or the like.

  In the case of pulverizing the entire amount, for example, the entire object is crushed using a crusher such as a disposer. The moisture content is, for example, 60 to 70% by weight, but takes a wide range in the case of processed products.

  The ultra-high temperature methane fermentation can be applied to any of an ultra-high temperature type, a slurry (wet) type, and a dry (dry) type.

  In the case of removing impurities, for example, when processing manure from a barn, feed rice straw and wheat straw are included as impurities, so it is preferable to remove them with a screen or a filter.

  The fermenter is composed of a tank in which the temperature in the fermenter is maintained at 60 ° C. or higher and air is completely shut off in order to maintain the activity of the ultrahigh temperature methane fermentation bacteria. The fermenter has different shapes and operating conditions depending on the solids concentration (usually in the range of 3 to 40% by weight). For example, in the case of a raw material having a high water content (up to a solid concentration of 10% by weight) mixed with washing waste water, a wet type complete mixing method fermenter, a raw material having a low water content (solids concentration of 30 to 30%) 40 wt%), it is preferable to use a so-called dry type plug flow type (extrusion type) fermenter.

  To process the same amount of organic waste, it takes 30 days for fermentation with medium temperature methane fermentation, and 15 days for fermentation with high temperature methane fermentation. On the other hand, in ultra-high temperature methane fermentation bacteria (60 ° C. or higher), the fermentation days can be set to about 10 days.

  Therefore, in a fermenter with a retention time (Retention Time) of 15 days or less than a high-temperature methane-fermenting bacterium (optimum temperature 55 ° C.) or a residence time of 30 days or so The fermentation process can be performed, the equipment can be made compact, and the cost for the equipment can be reduced.

[Ammonia recovery process]
The fermentation liquid extracted from the fermenter by the extraction pump is sent to an ammonia recovery tower in order to recover the ammonia contained in the liquid.

  The ammonia recovery tower is composed of a shower for spraying the fermentation liquid, a packed bed for bringing the fermentation liquid and the gas flowing in the ammonia recovery tower into gas-liquid contact, and a circulation tank for storing the liquid after ammonia recovery.

  Since ammonia in the fermented liquid is diffused in the ammonia recovery tower, this step is until the ammonia is recovered and transferred to the ammonia treatment tank in the next step.

  The temperature in the ammonia recovery tower is preferably maintained at the same level or higher than the temperature in the fermenter. This is because a large amount of ammonia in the fermentation broth is diffused and recovered. Specifically, it is 55-75 degreeC.

  As for the packed bed, all known structures can be adopted as long as the fermentation liquid and the gas flowing in the ammonia recovery tower can come into contact with each other. For example, a porous mat can be used. In order to achieve sufficient gas-liquid contact, it is preferable to provide a porous mat or the like in a shelf manner.

  In addition, in order to collect | recover the ammonia which could not be collect | recovered once, the fermentation liquid after the ammonia collection | recovery stored in the circulation tank is again sent to an ammonia collection tower by a circulation pump. Further, when the ammonia-recovered liquid stored in the circulation tank reaches a predetermined amount, it is sent to a slurry tank (not shown) or returned to the fermenter.

Returning the liquid after ammonia recovery to the fermenter has the following effects.
When the organic nitrogen (Kjeldahl nitrogen) contained in the organic waste in the fermenter is decomposed into ammonia nitrogen, and the amount of ammonia nitrogen in the fermentation liquid exceeds a certain level, methane fermentation in the fermenter It will lower the activity of the fungus (ammonia inhibition). Therefore, by returning the fermented liquid after recovering ammonia to the fermenter, the concentration of ammonia in the fermented liquid in the fermenter can be reduced, and the activity of the methane fermenting bacteria can be maintained. The density | concentration of ammonia nitrogen in the fermented liquor which methane fermentation microbe causes ammonia inhibition is 3000-3500 mg / L.

[Ammonia treatment process (feed production)]
The gas recovered in the gas-liquid contact between the ammonia recovery tower and the ammonia treatment tank (hereinafter referred to as “circulated air”) is transferred from the ammonia recovery tower to the ammonia treatment tank. In the ammonia treatment tank, the feed material is brought into contact (ammonia treatment).

The circulating air transfers the ammonia recovered by the ammonia recovery tower to the ammonia treatment tank.
And most of the transferred ammonia comes into contact with feed in the ammonia treatment tank, reacts and is consumed. Therefore, when the circulating air exits the ammonia treatment tank and flows into the ammonia recovery tower, the circulating air contains almost no ammonia.

  Ammonia treatment (ammonia long-time aeration) in the ammonia treatment tank is performed by adding, for example, about 1 to 3% by weight of ammonia per dry matter weight of the feed material under normal temperature to warming conditions. The amount of ammonia to be added can be sufficiently covered by the ammonia generated in the present invention.

  The ammonia treatment can be performed in a sealed room. The ammonia treatment period is preferably about 20 to 30 days.

  Treating the leaves and stems of cereals (for example, moss and semi-dry grass) with ammonia improves the digestibility as feed, nutritional value, and livestock preference, and also maintains the quality during storage. Cellulose, hemicellulose, ligno, and the like, which are main components of moss, are intertwined in a complex manner to form a hard tissue and form a tissue that is difficult to be decomposed by microorganisms and oxygen. When ammonia is allowed to act on this, amyloid decomposition (decomposition reaction such as cleavage of the cross-linking bond and reaction in which nitrogen is added) occurs, and the leaf stems of grains that are difficult for livestock to digest and absorb. However, it is easily digested and absorbed, has a high crude protein value, and becomes a feed with high added value.

  In other words, in feed materials such as cereal leaves and stems by ammonia treatment, ammonia acts on cellulose and hemicellulose to cause amylolysis, and as a result, amino acid polymers are formed from aminated degradation products. And increases in crude protein value.

  Methods for numerically indicating the effect of ammonia treatment include, for example, methods of measuring (1) an increase in the ratio of highly digestible fibers to low digestible fibers, and (2) an increase in total soluble nitrogen content. . If good ammonia treatment is performed, the numerical values of the above (1) and (2) can be made twice or more that of untreated products.

  In the feed production method of the present invention, ammonia present in a fermented liquid obtained by subjecting organic waste to ultrahigh temperature methane fermentation is recovered and used as ammonia for producing feed with high added value. Thus, by recovering ammonia from organic waste, it is possible to significantly reduce the cost of ammonia treatment compared to the case of using industrial chemical ammonia.

  In the ammonia treatment, when the concentration of recovered ammonia is about 10% by weight, the treatment is performed under heating conditions of, for example, about 40 ° C. rather than room temperature (outside temperature) in order to sufficiently obtain an effect on the grains and leaves. It is preferable. The reaction rate is increased by heating, and a sufficient ammonia treatment effect can be obtained. The heating temperature range during the ammonia treatment is preferably about 20 to 60 ° C.

  As mentioned above, although demonstrated about each process and the apparatus in each process, it is preferable on heat balance that the temperature in each apparatus in a series of processes is maintained at the temperature vicinity or more of a methane fermenter.

An embodiment of the present invention will be described with reference to FIG.
FIG. 5 shows a schematic diagram of the feed production system of the present invention. First, the flow of the fermentation liquid extracted from the fermenter will be described.

  The fermented liquor extracted from the fermenter 1 by the snake pump 7 (filtered as necessary) is directed to the packed bed 4 from the shower 3 provided in the upper part of the ammonia recovery tower 2 via the circulation pump 8. Sprayed. On the other hand, from the lower part of the packed bed 4 of the ammonia collecting tower 2, the circulating air circulating through the ammonia collecting tower 2 and the ammonia treatment tank 6 rises and comes into gas-liquid contact with the fermentation liquid in the packed bed 4.

  And the circulating air transfers the ammonia diffused (recovered) from the fermentation liquor in the ammonia recovery tower 2 to the ammonia treatment tank 6, and the ammonia and feed contact and react inside the ammonia treatment tank 6.

  The fermentation liquor after the ammonia is recovered by the ammonia recovery tower 2 is stored in the circulation tank 5 and sent again to the ammonia recovery tower 2 by the circulation pump 8. When the fermentation liquid in the circulation pump 8 reaches a predetermined amount, the fermentation liquid is sent to a slurry tank (not shown) by the extraction pump 9.

[Fermentation in fermenter]
Milking cow manure mixed with wheat straw pieces was put into the fermenter 1, and the temperature in the fermenter 1 was maintained at 65 ° C., and methane fermentation (ultrahigh temperature methane fermentation) was performed for 10 days. The ultra-high temperature methane-fermenting bacterium is a hydrogen-assimilating methane-producing bacterium.

[Ammonia recovery at ammonia recovery tower]
Thereafter, the fermented liquid at 65 ° C. is extracted from the fermenter 1 at a withdrawal rate of 5 L / min by the snake pump 7, subjected to automatic screen processing (filtration), and then sent to the ammonia recovery tower 2 by the circulation pump 8 and showered. The fermented liquor was sprayed from 3 to the packed bed 4 and brought into gas-liquid contact with the circulating air supplied from the circulating blower 10 serving as a gas supply unit in the packed bed 4. The packed layer 4 was formed by providing a porous mat in a stepped manner.

The temperature in the ammonia recovery tower 2 was 60 ° C., the temperature of the packed bed was 58 ° C., and the flow rate of circulating air circulating through the ammonia recovery tower 2 and the ammonia treatment tank 6 was 3 m ³ / min.
The pH of the fermentation broth was 8.0, the concentration of organic nitrogen was 600 mg / L, and the concentration of ammonia nitrogen was 3900 mg / L.

In the above state, the concentration of ammonia contained in the circulating air was measured by a first ammonia concentration monitor device 11 described later provided at the outlet of the ammonia recovery tower 2. Furthermore, only the temperature in the ammonia recovery tower 2 was changed to 50 ° C., 40 ° C., and 30 ° C., and similarly the concentration of ammonia contained in the circulating air was measured.
The results are shown in FIG. From this result, it can be seen that the higher the pH of the fermentation broth and the higher the temperature of the ammonia recovery tower 2, the better the ammonia is recovered.

[Ammonia concentration monitor]
A first ammonia concentration monitoring device 11 is provided in a gas feed line 12 between the outlet of the ammonia recovery tower 2 and the ammonia treatment tank 6. A gas return line 14 is provided between the outlet of the ammonia treatment tank 6 and the circulation blower 10, and a gas circulation line 15 is constituted by the gas feed line 12 and the gas return line 14. The gas return line 14 is provided with a second ammonia concentration monitor device 16.

  Further, a control for adjusting the amount of fermentation liquid and the amount of gas sent to the ammonia recovery tower 2 in response to the detection results of the first ammonia concentration monitoring device 11 and the second ammonia concentration monitoring device 16, the ammonia treatment tank The control part 18 which performs control of the 6 driving condition setting parts 17 is provided. A control signal from the control unit 18 is sent to the circulation pump 8 and the circulation blower 10 to adjust the amount of fermentation liquid and the amount of gas sent to the ammonia recovery tower 2.

Next, the structure of the ammonia concentration monitoring devices 11 and 16 will be described with reference to FIGS.
The ammonia concentration monitoring devices 11 and 16 include a glass film body 20, an internal liquid 21 placed in the glass film body 20, a first electrode 22 in contact with the internal liquid 21, and the outside of the glass film body 20. A liquid film forming part 23 provided on the surface of the liquid film, a second electrode 24 in contact with the liquid film 29 formed by the liquid film forming part 23, and a physical quantity corresponding to the ammonia concentration in the gas with the first electrode. And a detection unit 25 that is obtained from a voltage difference between the second electrodes.

  In this embodiment, the glass film body 20, the internal liquid 21, and the first electrode 22 have the same electrode structure as that of the glass electrode having the indicator electrode and the internal liquid in the pH meter. The second electrode 24 is an electrode corresponding to the reference electrode in the pH meter.

  The liquid film 29 formed by the liquid film forming unit 23 corresponds to the liquid to be measured in which the reference electrode in the pH meter is immersed. Here, the liquid film formation part 23 is comprised with water retention sheets, such as cloth, paper, and a porous body. The liquid film 29 may be formed with the structure of the outer surface of the glass film itself. Basically, it is an apparatus that can measure the pH in the liquid film from the voltage difference based on the difference between the hydrogen ion concentration in the internal liquid and the hydrogen ion concentration in the liquid film 29 via the glass film 20.

  The tip of the glass film body 20 is sealed in the wind box 26. The wind box 26 is provided with an inlet 27 and an outlet 28 for a gas to be measured. The detection unit 25 includes a display unit 30 that displays the obtained physical quantity or the ammonia concentration value corresponding to the physical quantity.

  Next, the measurement principle will be described. The gas G containing ammonia that has flowed in from the inlet of the wind box 26 passes through the liquid film forming unit 23 while being in contact with it, and flows out from the outlet 28. A liquid film 29 of water is formed in the liquid film forming part 23. The water liquid film 29 may be formed by adhering water contained in the gas G. In this case, the water liquid film 29 may not be formed in advance.

  When water contained in the gas adheres to the liquid film forming unit 23 or when a liquid film 29 of water is formed by spraying water or the like, ammonia in the gas dissolves in the liquid film 29. If the ammonia concentration is high, it dissolves much, and if the ammonia concentration is low, it dissolves little. The concentration of ammonia dissolved in the liquid film 29 increases and decreases until it reaches equilibrium with the ammonia concentration in the gas (FIG. 2). Therefore, the ammonia concentration in the liquid film 29 corresponds to the ammonia concentration in the gas.

  If a large amount of ammonia is dissolved in the liquid film 29, the pH value, which is a physical quantity of the liquid film 29, increases due to its alkalinity. If the ammonia concentration increases or decreases, the pH value also increases or decreases. The pH value, which is a physical quantity corresponding to the ammonia concentration in the gas, can be detected by the detection unit 25 based on the voltage difference between the first electrode 22 and the second electrode 24.

  Therefore, prepare several kinds of gas whose ammonia concentration in the gas is determined in advance with a detector tube, etc., bring the gas into contact with the liquid film, and measure the pH value in the liquid film in an equilibrium state. Thus, the ammonia concentration in the corresponding gas can be grasped by measuring the pH value of the liquid film by previously obtaining the relationship between them and preparing a calibration curve.

FIG. 3 shows the calibration curve. The calibration curve shown in FIG. 3 is a calibration curve used when carbon dioxide is contained in the gas. As can be seen from FIG. 3, there is linearity between pH values 7 and 10 when the ammonia concentration is in the range of 10 to 1000 ppm, and the calibration curve can be used to measure the ammonia concentration in this range. This is because carbon dioxide (H ₂ CO ₃ ) and ammonium hydroxide (NH ₄ OH) react with each other in the liquid film due to the presence of carbon dioxide to produce ammonium carbonate, thereby changing the high concentration of ammonia concentration. It is thought that it can detect by the change of pH value. In the production of the feed of the present invention, the calibration curve is used because the ammonia concentration is high (1000 ppm or more) and carbon dioxide is contained in the gas.

  FIG. 4 is a calibration curve in the case where the gas contains little or no carbon dioxide. As can be seen from FIG. 4, the ammonia concentration is low (10 ppm or less) and linear between pH values 7 and 9, and the calibration curve is used to measure the ammonia concentration in this low concentration range. be able to.

  That is, by using the ammonia concentration monitoring devices 11 and 16, it is possible to grasp in real time the increase or decrease in the ammonia concentration in the corresponding gas by increasing or decreasing the pH value of the liquid film 29, and the pH of the liquid film in which ammonia is dissolved. By measuring the increase / decrease in the physical quantity such as the value, the increase / decrease change in the ammonia concentration in the gas can be monitored.

  In the feed production apparatus according to the present embodiment, the ammonia concentration in the gas recovered by gas-liquid contact in the ammonia recovery tower 2 is monitored by the ammonia concentration monitor device 11, so the concentration of the recovered ammonia It is possible to grasp the increase and decrease change in real time. Therefore, when the ammonia concentration decreases or increases excessively, the ammonia concentration in the gas is adjusted by adjusting the amounts of the gas and the fermentation broth in the gas-liquid contact in a direction to correct the change. It can be kept within a certain range. Thereby, the feed with high added value which improved the digestibility as a feed, a nutritional value, and the preference of livestock can be manufactured without quality variation.

  Further, the recovered gas containing ammonia is sent to the ammonia treatment tank 6 through the gas feed line 12, where ammonia is consumed for making feed in the ammonia treatment tank 6, and the ammonia concentration is reduced (consumed to almost zero). The gas is returned to the circulation blower 10 through the gas return line 14 and circulated. The ammonia concentration before entering the ammonia treatment tank 6 is monitored by the first ammonia concentration monitor device 11, and the ammonia concentration after leaving the ammonia treatment tank 6 is monitored by the second ammonia concentration monitor device 16. It has become. Therefore, since the increase / decrease change of the consumption amount of ammonia in the ammonia treatment tank 6 can also be detected in real time, the operation condition setting of the ammonia treatment tank 6 is set as a subsequent response in consideration of the information on the consumption amount of ammonia. The part 17 can be adjusted.

  In the present embodiment, the control unit 18 can automatically maintain the ammonia concentration in the gas sent to the ammonia treatment tank 6 within a certain range, and the operating conditions such as the temperature of the ammonia treatment tank 6 can be automatically set. It can be adjusted in the direction of optimization.

It is sectional drawing of the ammonia concentration monitoring apparatus of the Example of this invention. It is a principal part expanded sectional view of the same apparatus. It is a figure of the calibration curve which shows the relationship between the ammonia concentration in the gas containing many carbon dioxides, and the pH value of a liquid film. It is a figure of the calibration curve which shows the relationship between the ammonia concentration in the gas which hardly contains a carbon dioxide, and the pH value of a liquid film. It is a schematic block diagram of the feed manufacturing system of this invention. It is a figure which shows the temperature dependence of the ammonia concentration in an ammonia recovery tower.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fermenter 2 Ammonia recovery tower 3 Shower 4 Packing bed 5 Circulation tank 6 Ammonia treatment tank 7 Snake pump 8 Circulation pump 9 Extraction pump 10 Circulation blower 11a, b Ammonia gas detection tube

Claims (7)

An ammonia concentration monitoring device for monitoring changes in ammonia concentration in a gas,
A glass membrane body;
An internal liquid placed in the glass film, a first electrode in contact with the internal liquid,
A liquid film forming part provided on the outer surface of the glass film body, a second electrode in contact with the liquid film formed by the liquid film forming part,
An ammonia concentration monitoring apparatus, comprising: a detection unit that obtains a physical quantity corresponding to the ammonia concentration in the gas from a voltage difference between the first electrode and the second electrode. The ammonia concentration monitoring device according to claim 1,
The ammonia concentration monitoring device, wherein the detection unit is configured to obtain a pH value of the liquid film as a physical quantity corresponding to an ammonia concentration in a gas. The ammonia concentration monitoring device according to claim 1 or 2,
The said detection part is provided with the display part which displays the value of the calculated | required physical quantity or the ammonia concentration corresponding to this physical quantity, The ammonia concentration monitor apparatus characterized by the above-mentioned. A gas supply unit;
An ammonia recovery tower that recovers ammonia produced by fermentation from a fermentation liquid produced by subjecting organic waste to methane fermentation into the gas by gas-liquid contact between the gas sent from the gas supply unit and the fermentation liquid,
An ammonia treatment tank in which the ammonia recovered in the gas in the ammonia recovery tower is brought into contact with a feed raw material;
A first ammonia concentration monitoring device provided in a gas feed line between an outlet of the ammonia recovery tower and an ammonia treatment tank, and a feed production system comprising:
4. The feed production system according to claim 1, wherein the first ammonia concentration monitor device is the ammonia concentration monitor device according to claim 1. In the feed production system according to claim 4,
A gas return line is provided between the outlet of the ammonia treatment tank and the gas supply unit, and a gas circulation line is constituted by the gas feed line and the gas return line.
A second ammonia concentration monitoring device is provided in the gas return line;
4. The feed production system according to claim 1, wherein the second ammonia concentration monitoring device is the ammonia concentration monitoring device according to claim 1. In the feed production system according to claim 5,
Control for adjusting the amount of fermentation liquor and the amount of gas sent to the ammonia recovery tower in response to the detection results of the first ammonia concentration monitoring device and the second ammonia concentration monitoring device, and setting the operating conditions of the ammonia treatment tank The feed manufacturing system characterized by including the control part which performs control of a part. Ammonia recovery step of recovering ammonia produced by fermentation from the fermentation liquid after methane fermentation into the gas by gas-liquid contact between the gas sent from the gas supply unit and the fermentation liquid,
An ammonia treatment step in which the ammonia recovered in the gas in the ammonia recovery step is brought into contact with a feed raw material;
A step of detecting an increase or decrease in the concentration of ammonia in the gas sent to the ammonia treatment step and controlling the amount of fermentation liquid and gas sent to the ammonia recovery tower based on the detection result;

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