JP2001192664A - Apparatus and method for producing carbide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a heat efficiency and a carbonization treatment efficiency by suitably controlling an amount of air supplied to a carbonization furnace so as to prevent excess and deficiency of air. SOLUTION: In this apparatus for producing a carbide having a carbonization furnace 2 for carbonizing an organic waste, a afterburning furnace 5 for burning a gas generated in the carbonization furnace 2, the apparatus is equipped with a means 2A for measuring temperature in the inside of the carbonization furnace 2, a means 5A for measuring an oxygen concentration in the afterburning furnace 5, a means 4 for controlling the amount of air supplied to the carbonization furnace 2 and a means 10 for controlling an amount of air supplied based on the measured temperature and oxygen concentration. The amount of air supplied to the carbonization furnace is controlled based on the temperature in the carbonization furnace and the oxygen concentration in the reburning furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to sludge discharged from a sewage treatment process, activated sludge, residues generated by anaerobic fermentation of sludge, livestock waste such as animal dung, animal and plant residues, and other organic wastes. The material is carbonized to improve the soil,
The present invention relates to a carbide production apparatus and a carbide production method for effectively utilizing as a dehydration aid, an activated carbon substitute, and the like.

[0002]

2. Description of the Related Art Conventionally, sludge discharged from a sewage treatment process or the like is often incinerated and then landfilled. In recent years, sludge and livestock waste have been composted for effective use due to lack of disposal sites and increasing awareness of the effective reuse of resources.However, in some regions, the compost produced cannot be fully processed. There is a problem.

[0003] In recent years, attention has been paid to carbonization, and attempts have been made to effectively use a carbide obtained by carbonizing sludge or the like as a substitute for activated carbon or a soil improving material.

[0004] Conventionally, carbide production apparatuses used for this carbonization treatment are roughly classified into batch type and continuous type. The carbonization furnace of the continuous type carbide production apparatus includes an internal heat kiln type, an external heat kiln type and a multi-stage screw type. and so on.

[0005] The carbide producing apparatus includes such a carbonizing furnace,
It mainly consists of a hot air generator for supplying hot air as a heat source to the carbonization furnace, and a reburning furnace for completely burning the pyrolysis gas generated by the thermal decomposition of organic waste in the carbonization furnace. I have. This carbonization furnace is connected with a fan and an air supply damper for supplying air from its wall as an oxygen supply source for complete combustion of the pyrolysis gas and for adjusting the furnace temperature. .

If the temperature in the carbonization furnace is too low, the carbonization treatment will be insufficient, and if it is too high, the components of the furnace will be damaged. Therefore, it is necessary to control the temperature within a predetermined temperature range.
Japanese Patent No. 47717 discloses that a temperature sensor is provided in a carbonization furnace to measure the temperature in the furnace, and the operation is controlled so that the temperature becomes a predetermined value.

[0007]

In the carbide production apparatus, the amount of air supplied to the carbonization furnace must be larger than the theoretical amount of air for completely burning the pyrolysis gas generated by carbonization. The excess or deficiency of the supplied air amount causes the following problems, respectively. Therefore, it can be said that the adjustment of the supplied air amount to the carbonization furnace is a very important control item.

[When the supply air amount is excessive] Since the total amount of exhaust gas discharged from the carbonization furnace increases,
Heat loss due to exhaust gas increases. The combustion temperature in the carbonization furnace decreases. If the combustion temperature is lowered, the carbonization becomes insufficient, and it is necessary to raise the temperature to a set value. In this case, the fuel consumption for maintaining the combustion temperature increases. Promotes the formation of nitrogen oxides.

[When the supply air amount is too small] Immediately after startup or when the calorific value of the pyrolysis gas is high, the combustion temperature in the carbonization furnace becomes abnormally high, and the components of the furnace are damaged by heat. Insufficient oxygen results in incomplete combustion of pyrolysis gas.

[0010] However, in the conventional carbide production apparatus, a method for controlling the amount of air supplied to the carbonization furnace has not been established. In order to completely combust the pyrolysis gas and prevent abnormal temperature rise in the carbonization furnace, The current situation is that an excess amount of air is supplied, and as a result, heat loss due to exhaust gas is large,
The device used a lot of fuel.

Japanese Patent Application Laid-Open No. 11-47717 describes that the temperature in the carbonization furnace is controlled.
No consideration is given to the control of the supply air amount, and it is not possible to reduce the exhaust gas amount by reducing the supply air amount to the necessary minimum, and thereby reduce the heat loss.

The present invention solves the above-mentioned conventional problems, and appropriately controls the amount of air supplied to a carbonization furnace to prevent an excess or deficiency of the amount of air. The aim is to provide a method.

[0013]

According to the present invention, there is provided a carbide producing apparatus comprising: a carbonizing furnace for carbonizing organic waste; and a reburning furnace for burning gas generated in the carbonizing furnace. Temperature measuring means for measuring the temperature inside the carbonization furnace; oxygen concentration measuring means for measuring the oxygen concentration in the reburning furnace; air amount adjusting means for adjusting the amount of air supplied to the carbonization furnace; Means for controlling the amount of air supplied to the carbonization furnace based on the measurement temperature of the measurement means and the concentration measured by the oxygen concentration measurement means.

[0014] In the carbide production method of the present invention, the organic waste is carbonized in a carbonization furnace, and the gas generated in the carbonization processing is burned in a reburning furnace. The amount of air supplied to the carbonization furnace is controlled based on the oxygen concentration in the combustion furnace.

In the present invention, the amount of air supplied to the carbonizing furnace is controlled as follows based on the measured value of the temperature in the carbonizing furnace and the measured value of the oxygen concentration in the reburning furnace.

First, an optimum value and an allowable upper limit value of the temperature in the carbonization furnace and a minimum value (lower limit value) of the oxygen concentration of the reburning furnace required for complete combustion of the pyrolysis gas are set.

[When the temperature in the carbonization furnace is lower than the optimum value]
Reduce the amount of air supplied to the carbonization furnace and raise the temperature inside the carbonization furnace. However, if the supply air amount is excessively reduced, the oxygen concentration in the reburning furnace decreases and incomplete combustion occurs. Therefore, the supply air amount is reduced within a range where the oxygen concentration does not become lower than a preset lower limit.

[When the temperature in the carbonization furnace is higher than the optimum value]
Irrespective of the oxygen concentration in the reburning furnace, the supply air amount is increased so that the temperature in the carbonizing furnace does not exceed a preset upper limit value.

As described above, by controlling the amount of air supplied to the carbonization furnace based on the temperature in the carbonization furnace and the oxygen concentration in the reburning furnace, the temperature in the carbonization furnace is maintained in an appropriate range, and In addition to reducing the carbonization efficiency and preventing damage to the furnace components due to excessive heating, and preventing incomplete combustion due to lack of oxygen, heat loss due to exhaust gas has been minimized by minimizing the amount of supplied air. Thus, the fuel consumption can be reduced.

On the other hand, if the supply air amount is controlled only based on the temperature of the carbonization furnace, there is a possibility that incomplete combustion may be caused due to lack of oxygen. Further, if the supply air amount is controlled only based on the oxygen concentration of the reburning furnace, the temperature inside the carbonization furnace may be excessively increased, and in either case, stable operation cannot be performed.

[0021]

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 carbide producing apparatus according to the present invention, and FIG. 2 is a graph showing the relationship between the oxygen concentration of the reburning furnace and the temperature of the carbonizing furnace.

In FIG. 1, reference numeral 1 denotes a hot-air generating furnace for supplying hot air to the carbonizing furnace 2. Reference numeral 3 denotes a fan for supplying air to the carbonization furnace 2, and the amount of air supplied to the carbonization furnace 2 is adjusted by an air supply damper 4. The carbonization furnace 2 is provided with a thermometer 2A.

Reference numeral 5 denotes a reburning furnace for completely burning the pyrolysis gas generated by carbonizing the raw organic waste in the carbonizing furnace 2, and is provided with an oxygen concentration meter 5A. 6 is a raw material supply hopper, and 7 is a cooling conveyor.

In 10, the measured values of the thermometer 2 A and the oxygen concentration meter 5 A are inputted, and based on these values, the amount of air to be supplied to the carbonization furnace 2 is calculated. 4 is a controller for adjusting the opening degree.

In FIG. 1, a carbonization furnace 2 is a multi-stage screw type carbonization furnace in which horizontal pipes 2a to 2d having a screw conveyor therein (hereinafter referred to as "transfer conveyors") are provided in four stages in the furnace. However, in the present invention, the type of the carbonizing furnace to be used is not particularly limited, and an internal heating kiln type, an external heating kiln type, and other carbonizing furnaces can be used.

In this carbide production apparatus, the raw material organic waste is introduced into the carbonization furnace 2 from the raw material supply hopper 6 and transferred inside the carbonization furnace 2 in the order of the transfer conveyors 2a, 2b, 2c and 2d. Is heated by hot air generated in the hot air generating furnace 1 and carbonized, and high-temperature carbide is discharged from the end of the lowermost transfer conveyor 2d. The carbide is cooled by a water-cooling jacket (not shown) or water spray while being transferred by the cooling conveyor 7, and the carbide hopper (not shown)
Is stored in The pyrolysis gas generated by the carbonization is completely combusted in the reburning furnace 5, and the exhaust gas from the reburning furnace 5 is discharged to the atmosphere after being used as a heat source for drying the raw material if necessary. You.

In such a carbonization process, in the carbide manufacturing apparatus of this embodiment, the measured value of the temperature in the carbonizing furnace 2 by the thermometer 2A and the measured value of the oxygen concentration in the reburning furnace 5 by the oxygen concentration meter 5A Based on this, the amount of air supplied to the carbonization furnace 2 is controlled.

That is, the measured value of the thermometer 2A and the measured value of the oxygen concentration meter 5A are input to the controller 10, and the amount of air supplied to the carbonization furnace 2 is calculated based on these values. An opening adjustment signal of the air supply damper 4 is output from the controller 10 so that the supply air amount is obtained, and the opening of the damper 4 is adjusted.

An example of a method of adjusting the opening of the damper 4 will be described with reference to FIG.

FIG. 2 is a graph in which the horizontal axis indicates the measured temperature of the carbonization furnace 2 and the vertical axis indicates the measured oxygen concentration of the reburning furnace 5.

For example, if the set value of the temperature of the carbonization furnace 2 is 900
C., the optimum value of the oxygen concentration at the outlet of the reburning furnace 5 is 5%.

The optimum point in FIG. 2 is point (1) where both the temperature and the oxygen concentration are optimum. The damper 4 is adjusted as described below so as to approach the optimum point (1).

When the oxygen concentration is 5% or more and the temperature of the carbonization furnace 2 is 900 ° C. or less (region (2) in FIG. 2), the air supplied to the carbonization furnace 2 becomes excessive, and the carbonization furnace 2 is cooled. Is determined to be performed, the opening degree of the damper 4 is reduced, and the supply air amount is reduced.

When the oxygen concentration is 5% or less (region (3) in FIG. 2), it is determined that the pyrolysis gas generated in the carbonization furnace 2 may be incompletely burned, and the opening degree of the damper 4 is determined. Increase to increase supply air volume.

The temperature of the carbonization furnace 2 is 900 ° C. or higher (FIG. 2)
In the case of (4)), it is determined that there is a possibility that the constituent materials of the furnace may be damaged by high temperature, and the opening degree of the damper 4 is increased to cool the furnace to increase the amount of supplied air.

As a result of such adjustment of the damper 4, the temperature,
The oxygen concentration becomes stable near the straight line (5) or (6) in FIG.

This point is the optimum point of temperature and oxygen concentration (1)
If any one of them is away from the optimum point (1) as described below, the other operating conditions are changed as shown below to change the optimum point (1). ) Is preferred.

Although the oxygen concentration is about 5%, when the temperature of the carbonizing furnace 2 is significantly lower than 900 ° C. (for example, 800 ° C. or less), the hot air generating furnace 1 Increase the set temperature of the outlet gas.

The temperature of the carbonization furnace 2 is about 900 ° C., but the oxygen concentration is much higher than 5% (for example, 7% or more).
In this case, the set temperature of the outlet gas of the hot-air generating furnace 1 is reduced in order to reduce the amount of air that is excessively supplied to cool the carbonizing furnace 2 and reduce the oxygen concentration.

As described above, according to the present invention, by controlling the amount of air supplied to the carbonization furnace based on the temperature of the carbonization furnace and the oxygen concentration of the reburning furnace, the amount of air supplied, and hence the amount of exhaust gas, can be reduced to a minimum. And the heat loss due to the exhaust gas can be reduced, so that the amount of fuel used in the hot air generator can be reduced by about 15% as compared with the conventional case.

[0042]

As described above in detail, according to the present invention, the temperature in the carbonization furnace is controlled by controlling the amount of air supplied to the carbonization furnace based on the temperature in the carbonization furnace and the oxygen concentration in the reburning furnace. By maintaining the temperature within an appropriate range, preventing the reduction of the carbonization efficiency due to the temperature drop and the damage of the constituent materials of the furnace due to the excessive temperature rise, the incomplete combustion due to the lack of oxygen is prevented, and the supply air volume is kept to the minimum required. As a result, heat loss due to exhaust gas can be reduced, and the amount of fuel used can be reduced. For this reason, the thermal efficiency and carbonization processing efficiency of the carbide manufacturing apparatus are greatly improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a carbide producing apparatus according to the present invention.

FIG. 2 is a graph showing the relationship between the oxygen concentration of a reburning furnace and the temperature of a carbonization furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot-air generator 2 Carbonization furnace 2A Thermometer 2a, 2b, 2c, 2d Transfer conveyor 3 Fan 4 Air supply damper 5 Reburning furnace 5A Oxygen concentration meter 6 Raw material supply hopper 7 Cooling conveyor 10 Controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23G 5/027 ZAB F23G 5/50 ZABN 5/50 ZAB ZABH ZABM B09B 3/00 ZABE (72) Inventor Horii Shigeki Kurita Kogyo Co., Ltd., 3-4-7 Nishi Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Yoshiaki Tanto 3-9-1 Nihonbashi, Chuo-ku, Tokyo 2nd Maruzen Building Tomoe Kogyo Co., Ltd. (72) Invention Person Hideo Yamazaki 95-1 Oyori, Sagara-cho, Haibara-gun, Shizuoka F-term (reference) 3K061 AB02 AC01 AC02 AC19 BA02 FA23 3K062 AB02 AC02 AC11 BA02 CA01 CB03 DA01 DA22 DB05 4D004 AA02 AC05 BA04 BA06 CA26 CA27 CB02 CB36 DA01 DA12 DA06 DA10 4G046 BA00 CC09 HA09 HC11 HC25 4H012 HA03 HA05 HA06

Claims (2)

[Claims] 1. A carbonization furnace for carbonizing organic waste,
A carbide producing apparatus having a reburning furnace for burning gas generated in the carbonizing furnace; a temperature measuring means for measuring a temperature inside the carbonizing furnace; and an oxygen concentration measuring means for measuring an oxygen concentration in the reburning furnace. Air amount adjusting means for adjusting the amount of air supplied to the carbonizing furnace; controlling the amount of air supplied to the carbonizing furnace based on the measured temperature of the temperature measuring means and the measured concentration of the oxygen concentration measuring means. And a means for producing a carbide. 2. A method for producing a carbide in which an organic waste is carbonized in a carbonization furnace and a gas generated in the carbonization is burned in a reburning furnace, wherein the temperature in the carbonization furnace and the oxygen concentration in the reburning furnace are determined. And controlling the amount of air supplied to the carbonization furnace based on the above method.