JP2001213683A - Method for manufacturing compost-like material and its manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture efficiently an product of the objective odorless high quality compost like materials without wasting fuel, time and labor regardless varing amounts quantities of the raw material by termination of the operation of the apparatus and through automatic judgement on the termination time of the heating treatment and to be able to treat the raw materials with the right treating time. SOLUTION: After heating organic wastes to dryness in the manufacturing method for the compost-like materials through the process of the heating treatment of the products at 100-200 deg.C, the heating time is set based on the detection of the specific components in the exhaust gas from the heating process. The apparatus manufacturing compost-like material has a heating device 11 for the heating treatment of an organic waste at 100-200 deg.C, and a detecting means 12 for detecting the specific components of the exhausted gas from the heating device 11 and a control means 14 which controls the heating time of the heating device 11 based on detected signals of the detecting means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing compost-like material, and more particularly, to a method for producing organic waste and producing a product having no odor similar to compost and recycling it. And an apparatus.

[0002]

2. Description of the Related Art Conventionally, a composting method is mainly used as a method of recycling organic waste such as biologically treated sludge, garbage, and livestock dung. The composting method is a method of fermenting an organic waste, and the obtained aged compost is a fertilizer excellent in handleability because the offensive odor component is decomposed, but the organic matter remains sufficiently.

[0003] However, such a composting method has a problem that it takes a long time of several weeks or more for processing, and in recent years, there has been an attempt to develop a technique for manufacturing a compost-like product in a short time. , Japanese Patent Application No. 11-235
No. 745 (hereinafter referred to as “prior application”) is a method of producing a compost-like material having almost no bad odor by removing the odor component by drying the organic waste and further heating at 100 to 200 ° C. A way to do that has been proposed. According to this method, by continuing the heating at 100 to 200 ° C. even after the heating and drying, there is no odor and the organic fertilizer remains sufficiently in a short treatment of about 10 to 20 hours. In addition, the salt content is not so high, and it is possible to obtain a product which is effective as an organic fertilizer and has excellent handling properties similar to aged compost.

In the processing method disclosed in the above-mentioned prior application, when further heating at 100 to 200 ° C. after the drying treatment, a preliminary test is sufficiently performed in advance in order to set an appropriate heating time, and a predetermined time is set. It is necessary for the operator to observe and analyze the processing status of the raw material during operation or during the processing, and to determine the end of an appropriate processing time.

[0005]

However, in the operation based on the results of the preliminary test, it is difficult to perform an appropriate operation in accordance with the amount of the raw material to be treated and a change in properties such as the water content of the raw material. If the treatment time is short, the treatment is insufficient and the product produces a bad smell.If the treatment time is made longer than necessary, there is no foul odor from the product.
Problems such as wasting fuel and reducing productivity have occurred. Further, the method in which the worker observes and analyzes the processing status to determine the end of the processing time requires a lot of manpower and time, and is industrially disadvantageous.

[0006] The present invention solves the above-mentioned problems of the prior application, and automatically terminates the operation of the apparatus by automatically judging the end time of the heat treatment even if the amount and properties of the raw materials are different. It is an object of the present invention to provide a method and an apparatus capable of processing raw materials in a processing time and efficiently producing a target high-quality product without a bad odor without wasting fuel, time and manpower. And

[0007]

The method for producing compost-like material according to the present invention comprises heating and drying organic waste,
A method for producing a compost-like product through a step of performing heat treatment at a temperature of up to 200 ° C., wherein a predetermined component contained in exhaust gas discharged from the heat treatment step is detected to set the heat treatment time.

[0008] The apparatus for producing compost-like products of the present invention comprises: a heating device for heating organic waste to 100 to 200 ° C;
It is characterized by comprising a detecting means for detecting a predetermined component of the exhaust gas discharged from the heating device, and a control means for controlling a heating processing time of the heating device based on a detection signal of the detecting means.

[0009] The heat-dried organic waste is 100 to 20
In the step of heating at 0 ° C., the moisture in the raw material and the odor component contained in the raw material due to the heating, or various odor components newly generated by decomposing the organic waste of the raw material by heating, etc. Is removed from the raw material and discharged as exhaust gas. In the present invention, based on the knowledge that the concentration of various odor components such as water vapor and ammonia, methyl mercaptan, hydrogen sulfide, methyl sulfide and the like in the exhaust gas generated by the heat treatment increases or decreases with the treatment, Is detected, and the heat treatment time is set based on this result.

For example, with respect to moisture, the processing can be terminated by heating for a certain period of time starting from the point when water vapor in the exhaust gas is no longer detected. Also,
With respect to various odor components such as ammonia, the concentration in the exhaust gas increases once with heating and then decreases, but after the peak of the ammonia concentration in the exhaust gas is detected, the heat treatment time is reduced until the ammonia concentration decreases to a predetermined ammonia concentration. , Preferably when the ammonia is almost not detected in the exhaust gas.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the present invention.
FIG. 2 is a sectional view showing an indirect heating device suitable for the present invention.

In the present invention, organic wastes such as sewage sludge, surplus sludge, digested sludge, and the like, biologically treated sludge, garbage, livestock dung, etc. generated in the biological treatment of wastewater and waste are heated and dried. Even after the moisture in the organic waste is gradually evaporated by this drying treatment and the moisture content becomes less than 1% and the drying is completed, the heating is continued at 100 to 200 ° C., and the wastewater is discharged from the heating treatment step. A predetermined component contained in the exhaust gas to be detected is detected, and a heat treatment time is set based on the result.

In the process of evaporating water by heating and drying the organic waste, while the water remains, the temperature of the organic waste to be treated is lower than 100 ° C., but the water is completely removed. If heating is continued even after the removal by evaporation, the temperature of the object to be processed rises to 100 ° C. or higher. When heating is continued for a predetermined time in this state, an aged compost-like product having almost no odor can be obtained. The heating temperature after completion of the drying is 100 to 200 ° C, preferably 150 to 200 ° C.
And Within this temperature range, moisture is completely evaporated and removed, and odor components are also volatilized and decomposed, while a good aged compost-like product can be obtained.

[0015] Specifically, as shown in FIG.
1. Using an apparatus provided with an exhaust gas detecting means 12, an exhaust gas treatment device 13 and a control device 14, an organic waste is put into a heating device 11 for heat treatment, and the exhaust gas generated in the heating device 11 is blown by a blower (not shown). Forced ventilation is performed, and a predetermined component in the exhaust gas is detected by the exhaust gas detecting means 12. The detection result is input to the control device 14, and the control device 14 determines continuation or termination of the heating based on the detection result, and outputs a stop signal of the heating device 11 when the heating is terminated. The exhaust gas that has passed through the exhaust gas detecting means 12 is processed by the exhaust gas processing device 13.

In the present invention, as described above, the components in the exhaust gas detected for setting the heat treatment time are contained in the exhaust gas by the heat treatment and are discharged, and depending on the condition of the object to be treated, And various odor components whose concentration increases or decreases. Among them, it is preferable to detect ammonia having the highest concentration among various odor components.

In the present invention, when the heat treatment time is set by detecting the water vapor in the exhaust gas, the heating is continued for a further predetermined time after the water vapor in the exhaust gas is no longer detected, and then the heating is terminated. It is preferable to obtain a good compost-like substance having almost no odor.

In this case, the predetermined time varies depending on the amount and properties of the organic waste to be treated, but usually, about 3 to 5 hours is sufficient.

On the other hand, when the heating time is set by detecting an odor component in the exhaust gas, for example, ammonia, by continuing the treatment, the ammonia concentration in the exhaust gas gradually increases and reaches a peak concentration. It is preferable to continue heating until the ammonia concentration decreases to a predetermined value, and to end the heating at this point. In this case, the ammonia concentration at which the heating is completed varies depending on the amount and properties of the organic waste to be treated, but usually the ammonia concentration is 100 pp.
By stopping the heating when the temperature becomes m or less, particularly 50 ppm or less, a compost-like substance having almost no odor can be obtained.

In the present invention, the means for detecting water vapor and odor components in the exhaust gas include a sensor for directly detecting water vapor and ammonia, and in the case of odor components, this component is once dissolved in a liquid and then dissolved in the liquid. Means for detecting the concentration in the medium can be employed.

In the present invention, if the organic waste is heated by the direct heating method, there is a risk of ignition. Therefore, it is preferable to perform the indirect heating using an indirect heating device as shown in FIG. preferable.

The indirect heating apparatus shown in FIG. 1 circulates a medium oil 2 in a circulation path of a heating vessel 1 having a double wall structure so that a heating medium circulates, and indirectly heats an object 10 to be treated inside. Is what you do. The medium oil 2 is heated by the heat exchanger 3 and circulates in the circulation path of the heating vessel 1. Organic waste is introduced from an upper inlet (not shown) of the heating vessel 1 and the rotating shaft 4
Of the medium oil 2
And the compost-like product of the product is taken out from the bottom outlet (not shown) of the heating vessel 1. Reference numeral 6 denotes a drive motor for driving the rotating shaft 4.

When heating the organic waste with such an indirect heating device, if the temperature of the medium oil 2 is maintained at 150 to 200 ° C., as will be apparent from the results of the examples described later,
Before the drying is completed, the object to be processed 10 having a temperature of less than 100 ° C. is maintained at 100 to 200 ° C. after the completion of the drying, and good heating is performed.

[0024]

The present invention will be described more specifically with reference to the following examples.

Example 1 1 ton of dehydrated sludge (water content: 83%) of excess sludge generated from a night soil treatment facility was processed at a target treatment temperature of 2 tons using an indirect heating device.
Heated at 00 ° C., the exhaust gas generated from the heating device was forcibly ventilated by a blower (blower amount 1 m ³ / min), ammonia in the exhaust gas was detected by an ammonia sensor, and based on the result, the heating time was controlled by a control device. Controlled. In this control device, the ammonia concentration in the exhaust gas is once 400 ppm
After that, when it became 50 ppm or less, the heating device was set to be stopped and the processing was performed by automatic control.
In 2 hours, a compost-like product having good properties without odor could be produced.

In this treatment, the temperature of the object to be treated rises to 100 ° C. or more after about 9 hours from the start of heating.
At this point, it was presumed that the drying was completed. Thereafter, the temperature of the object was in the range of 150 to 200 ° C. The relationship between the elapsed time from the start of the heating and the ammonia concentration in the exhaust gas is as shown in FIG. 3. When the ammonia concentration is, the heating is terminated and water is added to the compost-like material taken out. When the odor was confirmed, there was a strong sludge odor before the ammonia concentration peaked, and there was a slight sludge odor even at the ammonia concentration peak. However, after that, the ammonia concentration became 50 ppm
At the time of the following, a product with almost no odor could be obtained.

From this result, it can be seen that a product having no odor can be obtained by performing the heat treatment at 100 to 200 ° C. until almost no ammonia in the exhaust gas is detected.

Embodiment 2 In Embodiment 1, a humidity detector is provided in place of the ammonia sensor to detect the water vapor in the exhaust gas.
When heating was continued for 3 hours after the water vapor in the exhaust gas was no longer detected, the heating device was set to stop and the processing was performed by automatic control. Similarly, the time required for the production of compost-like material was about 12 hours. A compost-like product having good properties without odor could be produced in a short time.

In this treatment, the relationship between the time elapsed since the detection of water vapor in the exhaust gas was stopped and the compost-like material taken out after heating was stopped at that time was examined in the same manner as in Example 1. As shown in Table 1 below, it can be seen that a product without odor can be obtained by ending the treatment after continuing heating for 3 hours after the detection of water vapor in the exhaust gas is stopped.

[0030]

[Table 1]

When various other organic wastes having different properties such as moisture content were treated by the control methods of the above-mentioned Examples 1 and 2, it was found that a compost-like material having almost no odor was produced. Was completed.

[0032]

As described above in detail, according to the method for producing a compost-like material and the apparatus for producing a compost-like material of the present invention, even if the amounts and properties of the raw materials are different, they are generated by heat treatment at 100 to 200 ° C. By detecting the concentration of the components in the exhaust gas, and automatically determining the end time of the heat treatment based on the result and terminating the operation of the apparatus, the raw material can be processed in an appropriate processing time, and the target It is possible to efficiently produce a high-quality compost-like product without odor by automatic operation without wasting fuel, time, or manpower.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a method for producing a compost-like material and an apparatus for producing a compost-like material according to the present invention.

FIG. 2 is a cross-sectional view showing an indirect heating device suitable for a heat treatment in the present invention.

FIG. 3 is a graph showing changes in the concentration of ammonia in exhaust gas in Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating container 2 Medium oil 3 Heat exchanger 4 Rotating shaft 5 Stirring blade 6 Motor 10 Workpiece 11 Heating device 12 Exhaust gas detection means 13 Exhaust gas treatment device 14 Control device

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Claims (4)

[Claims] 1. After drying organic waste by heating, 100
A method for producing a compost-like product through a heat treatment step at a temperature of 200 to 200 ° C., wherein a predetermined component contained in exhaust gas discharged from the heat treatment step is detected to set the heat treatment time. Manufacturing method of similar products. 2. The method for producing a compost-like product according to claim 1, wherein a predetermined heat treatment time is set from a point in time when water vapor in said exhaust gas is substantially no longer detected. 3. The method for producing a compost-like product according to claim 1, wherein after detecting the peak of the ammonia concentration in the exhaust gas, the heat treatment time is set until a point at which the ammonia concentration falls to a predetermined ammonia concentration. 4. A heating device for heating organic waste to 100 to 200 ° C., a detecting device for detecting a predetermined component of exhaust gas discharged from the heating device, and the heating device based on a detection signal of the detecting device. An apparatus for manufacturing a compost-like product, comprising: control means for controlling a heat treatment time of the apparatus.