JP2003003173A - Carbonization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbonization method by which a carbonized product having physical properties suitable for new uses is obtained by controlling carbonization conditions in an oven and by which an exhaust gas by-produced on the carbonization can usefully be used for pyroligneous acid production and the like. SOLUTION: This carbonization method is characterized by stirring and circulating air in a carbonization oven 1 with a stirring circulation means 4 to uniform the inner temperature of the oven on the carbonization. Another carbonization method is characterized by introducing air or air and steam from a refinement blower into the oven through an oven floor portion to carbonize and refine a carbonization material. Exhaust gas by-produced on the carbonization is cooled and recovered for each temperature to obtain pyroligneous acid liquids having different physical properties, respectively. The exhaust gas by-produced on the carbonization is burned, and the generated heat is recovered in a heat storage chamber or directly brought into a carbonization material, thus using the heat in a drying and heating process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbonization method capable of uniformly carbonizing a carbide having physical properties corresponding to a new application and effectively utilizing exhaust gas generated during carbonization.

[0002]

2. Description of the Related Art Conventionally, a carbonization furnace that has been installed in Yamamura is
They were earth and stone kilns, and mainly used charcoal from hardwood to obtain fuel charcoal. On the other hand, in continuous mechanical furnaces including rotary furnaces and fluidized furnaces, sawdust and waste materials generated from lumber mills in the town are crushed into chips and carbonized to be used as an industrial raw material or a charcoal raw material. The flue gas generated during carbonization was cooled in soil kilns and stone kilns to recover wood vinegar, and burned in a mechanical furnace to directly contact combustion waste gas with carbonized raw materials for drying.

In recent years, the development of new uses of charcoal has progressed, and it has been applied to agricultural lands as a soil improving material, used on grass fields or slopes of golf courses, or mixed with livestock feed. There is a demand for a carbide having physical properties corresponding to a new application such as being used as an underfloor hygroscopic material or a VOC adsorbent. However, it was difficult to obtain a carbide with uniform physical properties due to the large difference in carbonization temperature between the top and bottom in the furnace in the Yamamura deferment type kiln and stone kiln. On the other hand, in the mechanical furnace, the capital investment is large, so it is necessary to increase the amount of processing, the area of the raw material is limited, and the energy cost for chipping is also large.

[0004]

SUMMARY OF THE INVENTION According to the present invention, by controlling the carbonization conditions in a furnace, a carbide having physical properties suitable for a new use can be obtained, and at the same time, a wood vinegar solution can be obtained from smoke generated during carbonization. It is an object to provide a carbonization method that can effectively use smoke.

[0005]

The first of the means for solving the problems is that the air in the furnace of the carbonization furnace is agitated and circulated by the agitation circulation means to make the temperature in the furnace during carbonization uniform and carbonize. Is. The second solution is characterized in that air or air and steam are introduced into the furnace from the hearth of the carbonization furnace by a refining blower for carbonization and refining. A third solution means is that, in the first solution means, the agitation circulation means is a circulation gas duct provided in the carbonization furnace main body, and the agitation and circulation of the furnace air is performed by a circulation blower attached to the circulation gas duct. Characterize. Fourth solution
In the first solution means, the stirring and circulation means is a circulation fan provided at the top of the carbonization furnace main body, and the furnace air is stirred and circulated by the circulation fan. A fifth solution means is characterized in that, in the first to fourth solution means, the flue gas generated at the time of carbonization is cooled and recovered for each temperature to obtain a wood vinegar solution having different physical properties. A sixth solution means is that in the first to fourth solution means, a part or all of the flue gas generated at the time of carbonization is burned, and the generated heat is recovered in the heat storage chamber or is directly contacted with the carbonaceous material for drying. -Characterized by being used in the temperature raising step.

In the process of carbonization in the fixed bed carbonization furnace of the present invention, first, when the carbonaceous material is burned at the kiln mouth to dry and heat the carbonaceous material, spontaneous carbonization of the carbonaceous material starts at 280 to 300 ° C. Carbonization starts from the top of the furnace, then proceeds toward the bottom of the furnace, and finally opens the kiln opening to increase the amount of introduced air and raise the temperature.
After passing through a refining process in which residual volatile components are discharged and baked, air is shut off and cooled. In this carbonization step, the difference in carbonization temperature between the furnace top and the hearth is usually 200 ° C. or more, and therefore the physical properties of the obtained carbide are significantly different between the upper and lower parts of the furnace. To solve this, mechanically stir and circulate the in-furnace gas at the top of the furnace, or take out the in-furnace gas from the top of the furnace with a circulation blower installed outside the furnace, and By blowing air uniformly, the temperature is made uniform and carbonization is performed. Further, in the refining process, air and steam are introduced uniformly from the hearth where the temperature tends to be low, so that the temperature rise in the hearth is assisted and refining and activation are performed.

The temperature inside the furnace is adjusted by the amount of air at the time of temperature rise and the amount of air introduced into the furnace at the time of refining. If the temperature inside the furnace is too high, endothermic reaction is effected by spraying steam or water. To lower the temperature. In addition, air and steam are introduced to react with charcoal to obtain activated charcoal. In this way, the temperature in the furnace is raised and carbonized while being uniformized. However, it becomes easy to adjust the carbonization temperature according to the purpose of use of the carbide, and the activation reaction becomes possible. The flue gas generated in the process of uniformizing the temperature in the furnace and promoting carbonization can be cooled and recovered for each temperature to obtain a wood vinegar liquid having different physical properties. It is differentiated from the wood vinegar obtained by cooling the flue gas generated by the partially different carbonization temperatures of the conventional furnace. The flue gas during carbonization has a low calorie in flue gas mixed with the water content of the carbonaceous material and is difficult to burn, but in the case where carbonization proceeds at a uniform temperature, the part with a high gas calorie can be burned. It becomes easier and can be burned to store the amount of heat in a heat storage chamber made of bricks, heat can be recovered using a heat exchanger, or combustion gas can be directly used for drying and heating the carbonaceous material. You can

[0008]

1 is a side view of a carbonization furnace using a circulation blower, FIG. 2 is a sectional view of FIG. 1, and FIG. 3 is a side view of a carbonization furnace according to another embodiment. The carbonization furnace body 1 can be made to have any size, but in the embodiment, it is made of a refractory brick and an adiabatic refractory having an inner width of 2.3 m, a height of 2.4 m and a length of 4.7 m. The carbonization furnace body 1 may be provided with a front heating stove 2. The role of this pre-burning stove 2 is used in the carbon material drying process and the temperature raising process, and firewood, kerosene, or heavy oil that does not become carbonaceous material is used as a combustion material, but the exhaust gas from other furnaces is used as a substitute. You can also do it. Further, the front heating stove 2 is provided with an inverter motor and a stove blower 3 provided with an automatic control valve at the front and rear to perform necessary temperature adjustment. However, since the spontaneous carbonization starts when the carbonaceous material exceeds 280 to 300 ° C, the pre-stove 2 is not used.

Further, the carbonization furnace body 1 is provided with a stirring / circulating means (4,
100) stirs and circulates the air in the furnace. The circulating gas duct 4 as a stirring / circulating means circulates the in-furnace gas of the carbonization furnace main body 1 by a circulating blower 5 equipped with an inverter motor and equipped with an automatic control valve to make the in-furnace temperature uniform. The agitating and circulating means of a different system is a furnace gas circulation fan 100 provided at the top of the carbonization furnace body 1 as shown in FIG. In this case, the gas is not circulated by the circulation blower 5, but it can be used in combination. When spontaneous carbonization of carbon material occurs in the carbonization furnace body 1, the front heating stove 2 is stopped, and air is supplied to the inside of the furnace by the air supply blower 6 with an inverter motor, and the temperature is controlled to a predetermined temperature. While supplying air. However, the air can be supplied by the refining blower 7 equipped with an inverter motor, a control valve, and a flow meter. When the temperature in the furnace reaches a predetermined temperature, a refining process is started if necessary. The refining process is not necessary for low-temperature carbonization, but for high-temperature carbonization, a large amount of air is blown from the hearth at once to heat up the carbides, or steam is used to activate the reaction. To do. Since it is important to control the air volume in this refining process, the refining blower 7 has a flow meter 8 in particular.
Check and check the flow rate visually.

The circulating gas, refining air and steam are uniformly dispersed in the furnace by a dispersion plate provided in the hearth 10. The dispersion plate of the hearth 10 may have a structure used in a general fluidized furnace. Further, when only refining air is introduced from the hearth portion 10, it is possible to arrange pipes with holes and connect them to the air blower. Further, a steam introducing pipe 17 may be provided in the pipe of the refining blower 7 to introduce air and steam together. This method is also used as a simple uniform refining method or a method for producing activated charcoal when refining in a conventionally used earth kiln, stone kiln, brick kiln or the like. The flue gas generated during carbonization passes through a cooler 12 provided in the middle of the flue gas duct 11 to be water-cooled and the wood vinegar solution is recovered. The size of the cooler 12 is arbitrarily designed according to the amount of gas, but it is desirable to have a structure that allows easy removal of tar when it adheres.

The wood vinegar liquid that has flowed down the cooler 12 is collected by the flow-down pipe 13 according to the temperature of the flue gas. When the flue gas is burned and recovered as heat, it is ignited by the afterburner 111 of the exhaust gas combustion chamber 110, and the high temperature combustion gas is used through the heat resistant duct 112, as shown in FIG. The exhaust heat can be used by directly using the combustion gas, but can be recovered and used by using a heat storage chamber or a heat exchanger.
Further, wood gas that has been cooled by the cooler 12 to separate the wood vinegar solution can also be used. Combustion gas or hot air obtained by heat exchange is brought into contact with the carbonaceous material and used for drying the carbonaceous material or in a temperature rising step.

Example 1 A carbonization furnace main body 1 shown in FIG. 1 (inner diameter width 2.3 m, height 2.4)
m, length 4.7 m) is the front heating stove 2 (diameter 70 cm,
The length was 1 m), and firewood or kerosene (burner with an oil amount of 5 to 15 liters / h) was used as the fuel material.
The hearth 10 has a thickness of 6 cm at a position 30 cm above the bottom.
A heat resistant pipe was embedded in a castable refractory having a diameter of 1 cm, and holes were drilled in this pipe so that the open area ratio was 1% to obtain a dispersion plate of the hearth. The heat-resistant pipe of the circulating gas duct 4 is 8
I used inches. The circulation blower 5 used was 40 m ³ / min. The air supply blower 6 used was 6 m ³ / min. The refining blower 7 used was 10 m ³ / min.

An inverter motor was attached to each of the blowers 5, 6 and 7 to adjust the air flow rate, and at the same time, precise temperature control was performed using an automatic control valve. In addition, temperature adjustment is
The control box 20 and the thermocouple 21 inserted into the carbonization furnace main body 1 are connected to detect temperature information from the thermocouple 21,
The rotation speed of each blower 5, 6, and 7 and the flow rate by the control valve are adjusted by a command from the. The flue gas cooler 12
A cylinder with a water cooling jacket, the cylinder made of an acid resistant material. The inner diameter of the tube is 42 cm and the height is 3.5 m.
Further, the smoke exhaust duct 11 is provided with a damper 14 so that the amount of exhaust gas can be adjusted. A circulating gas duct 4 for discharging a part of exhaust gas from refining from the top of the carbonization furnace main body 1
The branch pipe outlet 40 was provided, and a damper 41 was also attached to this pipe. The wood vinegar liquid that was cooled and recovered from the flow-down pipe 13 was separated into smoke collection temperatures through a recovery hose and collected in respective collection tanks.

Using the carbonization furnace according to the present invention, the carbonizations of Experiments 1 to 3 were conducted, and the obtained carbides and wood vinegar solutions were analyzed to examine their effects. In Experiment 1, for comparison, a refining method of supplying circulating gas or air from the hearth surface was not performed as a conventional method, and in Experiments 2 and 3, carbonization was performed by the method of the present invention.
The carbon material used was 4.5 to 11 cm in diameter, 1.8 m in length and 45% in water content (converted to dry matter), and 1.2 to 1.5 t of waste root removal material was used as the combustion material. The following table shows the temperature differences in the processes such as drying, heating, and refining.

[Table 1]

After the completion of carbonization and cooling, the front door of the furnace is opened to take out the carbide. At this time, the refining degree is measured by a refining meter which measures the electric resistance of the charcoal in each part of the furnace to check the degree of carbonization. At the same time, the physical properties of the carbide were analyzed to examine the state of carbonization in the furnace, and the results in the following table were obtained.

[Table 2] In the above analysis, the refining degree was measured by "Sanyo Denki's refining degree meter", the industrial analysis was conducted by "JIS M 8812", and the iodine adsorption performance was "JIS K 1474".
Analyzed by As is clear from this result, in the conventional furnace, the temperature difference between the furnace top and the furnace bottom was large, and the physical properties of the obtained carbides were also very different, but the method of the present invention made it possible to obtain almost uniform carbides ( See Figures 4-6).

Next, in this experiment, the wood vinegar solution obtained by cooling the flue gas was analyzed, and the following results were obtained. The wood vinegar is collected at a flue gas temperature of 80-9 below the cooler.
The three fractions of 3 ° C., 94 to 113 ° C. and 114 to 220 ° C. were collected separately and the components were compared.

[Table 3] As shown by the above results, in the conventional furnace, the decomposition of hemicellulose, the decomposition of cellulose, and the decomposition of lignin occur at the same time, but according to the present invention, the initial wood vinegar has a relatively high water content. The obtained product can be used for each application. For example, a wood vinegar containing a large amount of phenols is effective when used as an anti-termite agent under the floor of a wooden building, and a material having a high acidity is effective as a plant growth promoter when diluted. As described above, it is the first time that the present invention can differentiate the wood vinegar solution without using the distillation method.

Example 2 Carbonization was carried out in a fixed bed carbonization furnace of the same type as that used in Example 1 and in a furnace having a structure in which three circulation fans 100 were attached to the furnace top as shown in FIG. As the carbonaceous material, larch thinned wood having a diameter of 6 to 8 cm and a length of 1.5 m and a water content of 34% was used as 3.1 t (dry matter conversion). When setting up the carbonaceous material, it was set up with a gap between the left and right wall surfaces. The circulation fan 100 was rotated by a blade made of SUS310S and having a diameter of 50 cm so as to be located 30 cm below the furnace ceiling so that the gas could flow upward. The carbonization time was 34 hours for the drying step and 86 hours for the elevated temperature carbonization, and the refining step was performed for 4 hours at an air volume of 280 m ³ / h using the refining blower 7 of FIG. 3 as in Example 1. The final carbonization temperature was set to 845 ° C. to complete the carbonization.

After cooling, the refining degree of the carbide was measured at each site in the furnace, and as a result, a very approximate value was obtained. The data obtained are shown in the table below.

[Table 4] From the above results, it was proved that the carbonization was performed uniformly. In the carbonization process performed in the same manner, only the refining process was changed. That is, the refining blower 7 shown in FIG.
³ / h and 30 kg / h of steam were introduced from the steam introducing pipe 17 to carry out refining and activation at the same time. This step was performed for 8 hours. At this time, the reaction temperature was 810 ° C. and the coal collection rate was 18.7%. When the physical properties of this carbide were compared with the case where the above steam was not used, the following results were obtained.

[Table 5]

Next, the flue gas generated during carbonization is introduced into the exhaust gas combustion chamber 110 with an afterburner and burned, and the exhaust heat is used in the adjacent carbonization furnace of the same type. Exhaust gas combustion chamber 11
0 is a cylindrical type with an inner diameter of 700 mm and a length of 1.5 m, and a thickness of 1
As shown in FIG. 3, which is made of a heat resistant material of 00 mm, an afterburner 111 with a controller for burning 3 to 10 liters / h of kerosene is additionally installed at the bottom. Secondary air for exhaust gas combustion is also supplied from the blower attached to this burner. The combustion gas that has exited the exhaust gas combustion chamber 110 is supplied to a front heating stove of an adjacent carbonization furnace main body (not shown), which is the next destination, through a heat resistant duct 112 having an inner diameter of 200 mm.

The flue gas generated in the second embodiment is introduced into the exhaust gas combustion chamber 110 without being cooled.
The calorific value of the generated gas is low for 4 hours and 24 hours of the next temperature raising step, and cannot be used. After 58 hours, the afterburner 111 is ignited and 8 liters / h of kerosene is burned for 6 hours to raise the temperature, and the kerosene amount is gradually reduced after the combustion chamber exceeds 800 ° C. After 72 hours, the kerosene combustion amount is increased. 3 liters /
However, the combustion chamber was maintained at 850 to 900 ° C. The calorie of the gas generated at this time is estimated to be 60,000 calories / h on average, and the combustion exhaust gas of about 90,000 calories / h together with the amount of kerosene is supplied to the pre-burning stove of the adjacent carbonization furnace body for 52 hours for 52 hours. , Used in the drying / heating process. The heat balance of the carbonization process was estimated to be 33% for charcoal, 37% for exhaust gas calorie utilization, and 30% for heat loss. It was the first time in the furnace of the present invention to obtain and utilize such high-calorie flue gas in a fixed furnace.

Example 3 In this example, carbonization was performed by the method of the present invention using an ancient Japanese kiln. The size of the clay kiln is 1
5 kg / bale is 70 bale kiln, and the approximate size is length 7
It is a kiln with m, width of 3 m, and height of 1.6 m, and is baked for about 10 days. At the bottom of this kiln, SUS3 with a length of 2m
10S 2 inch pipe with 4mm diameter holes 10
Five pieces were connected to a 6-inch pipe at 50 cm intervals, and the 6-inch pipe was extended and taken out of the kiln to be connected to a blower. The blower used had an air volume of 5 liters / minute. Refining was carried out for 3 hours in this soil kiln by the usual carbonization method and the refining process of the present invention using a refining air introduction pipe provided in the hearth. Alumel chromel thermocouple length 1.4 to observe the refining situation
Two pieces of m were inserted into the kiln at the heights of 13 cm and 15 cm, and the point where the temperature difference between the upper and lower sides was reduced was the end point of the refining. Further, the longer the refining time, the higher the carbonization temperature, and it was possible to control the carbonization temperature to the target.

The following table shows the results of carbonization by introducing air or air and steam from the hearth without stirring or circulating the air in the furnace and the results of carbonization by the conventional method.

[Table 6] By using the refining method of the present invention as described above, a carbide having uniform physical properties was easily obtained.

[Brief description of drawings]

FIG. 1 is a side view showing a carbonization device of the present invention.

FIG. 2 is a cross-sectional view showing a carbonization device of the present invention.

FIG. 3 is a sectional view showing another carbonization device of the present invention.

FIG. 4 is a temperature rise curve diagram in the carbonization furnace in Experiment 1.

FIG. 5 is a temperature rise curve diagram in the carbonization furnace in Experiment 2.

FIG. 6 is a temperature rise curve diagram in the carbonization furnace in Experiment 3.

[Explanation of symbols]

1 Carbonization furnace body 2 front heating stove Blower for 3 stoves 4 Circulating gas duct 5 Circulation blower 6 Blower for air supply 7 Refining blower 8 flow meter 10 hearth 11 Smoke exhaust duct 12 Cooler 13 Downflow pipe 14 Damper 17 Steam introduction pipe 20 control box 21 Thermo Couple 40 Branch pipe outlet 41 Damper 100 circulation fan 110 Exhaust gas combustion chamber 111 Afterburner 112 Heat-resistant duct

Claims (6)

[Claims] 1. A stirring and circulating means (4, 4) for circulating air in the furnace of the carbonization furnace.
100) a method of carbonizing, which comprises agitating and circulating by 100) to homogenize the temperature in the furnace during carbonization and carbonize. 2. A carbonization method characterized by introducing air or air and steam from a hearth (10) of a carbonization furnace into a furnace by a refining blower (7) for carbonization and refining. 3. The stirring / circulating means is a circulating gas duct (4) provided in the carbonization furnace body (1), and the circulating air blower (5) attached to the circulating gas duct (4) stirs and circulates the air in the furnace. The carbonization method according to claim 1, wherein 4. The stirring and circulating means is a circulation fan (100) provided on the top of the carbonization furnace body (1), and the circulation fan (100) stirs and circulates the air in the furnace. The carbonization method according to claim 1. 5. The carbonization method according to any one of claims 1 to 4, wherein flue gas generated during carbonization is cooled and recovered for each temperature to obtain a wood vinegar having different physical properties. 6. A feature of burning part or all of the flue gas generated during carbonization, recovering the heat generated in the heat storage chamber or directly contacting with the carbonaceous material for use in the drying / heating process. The carbonization method according to any one of claims 1 to 4.