JP2789303B2 - Dry distillation incineration method and apparatus for organic solvent-containing waste - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for dry distillation incineration of organic solvent-containing waste, and more particularly to waste containing an organic solvent which is easily volatile and flammable, such as paints, printing inks, and the like.
Safe and dry incineration of waste liquids, residual liquids such as adhesives and degreasing detergents, and wastes and filters on which they are adhered and impregnated, as well as wastes containing these and other flammable substances. It is intended to provide a method and an apparatus therefor.

[0002]

2. Description of the Related Art A combustible waste is housed in a carbonization furnace, a part of which is burned under a limited amount of supplied air, carbonized, and the generated carbonized gas is guided to a combustion furnace for complete combustion.
Ashing and burning of waste from a carbonization furnace is conventionally known, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-141639. In the dry distillation incineration means, when waste containing an organic solvent having a low boiling point is mixed, when the waste is charged and stored in the dry distillation furnace, and furthermore, during the dry distillation step, the atmosphere in the furnace becomes organic. Explosive mixtures consisting of solvent vapor and air may cause an explosion, deflagration, etc., and are extremely dangerous. Therefore, organic solvent-containing waste is separated from other waste, It has to be treated by means of dry distillation in coke combustion gas as shown in 1-60731.

[0003]

Liquids containing organic solvents such as paints and printing inks, and wastes such as impregnated substances adhered thereto are used to prevent fires and unpleasant odors due to evaporation of solvent vapors. Usually, they are stored in sealed cans and taken out of the sealed cans for incineration. However, the work is troublesome, and it is necessary to store and dispose of the waste remaining in the sealed cans. On the other hand, when the organic solvent-containing waste was put into a dry distillation furnace in a sealed can, the mixed atmosphere of the organic solvent vapor and air leaked from the can was sparked by collision of a metal can or the like, or simultaneously. There is a risk of ignition explosion due to electrostatic discharge sparks of waste plastics and the like, and it has been difficult to stably continue dry distillation.

[0004]

According to the present invention, an organic solvent-containing waste is subjected to dry distillation incineration, and the atmosphere in the dry distillation furnace is replaced with an inert gas in advance before charging the organic solvent-containing waste. The atmosphere in the carbonization furnace from the input of waste to the end of the carbonization step should not exceed the combustion limit oxygen concentration of the carbonized gas consisting of organic solvent vapor generated by carbonization and pyrolysis gas. And a method suitable for the process, wherein the carbonized gas generated by the carbonization and combustion of the waste is introduced into a combustion furnace for complete combustion.

That is, according to the method of the present invention, after the atmosphere in the dry distillation furnace is replaced with an inert gas to reduce the atmosphere in the furnace to a concentration lower than the combustion limit oxygen concentration of the organic solvent vapor, the waste containing the organic solvent is introduced into the furnace. The first step of lowering the oxygen concentration in the furnace atmosphere by injecting and depositing and further proceeding with the supply of the inert gas, and igniting a part of the lower layer of the deposited waste, the air having the combustion limit oxygen concentration described above A second stage of supplying a gaseous mixture of hydrogen and inert gas to form a combustion oxide layer on the entire lower layer of the sedimentary waste and starting the dry distillation of the upper waste, and a dry distillation gas containing an organic solvent vapor generated. In order to keep the oxygen concentration below the combustion limit of the carbonized gas, the mixing ratio of the inert gas in the supply mixture is gradually reduced and the supply amount is adjusted, and finally only air is supplied. To continue stable carbonization and finish incineration through ash combustion It consists third stage, the second stage,
A dry distillation incineration method for organic solvent-containing waste, characterized in that the dry distillation gas generated in the third stage is guided to a combustion furnace to be completely burned.

The inert gas used in the first stage of the treatment method may be an exhaust gas obtained by burning fuel in a combustion furnace, or a nitrogen gas or a carbon dioxide gas supplied from a separate gas source. As the inert gas to be mixed with the air used in the second and third stages, the exhaust gas obtained by burning the above-mentioned dry distillation gas in a combustion furnace can be used.

The apparatus of the present invention is suitable for carrying out the above-mentioned processing method, and comprises a carbonization furnace, a combustion furnace, a combustion cylinder provided in a pipe connecting the two furnaces, and a combustion exhaust gas from the combustion furnace. In the incinerator for waste carbonization with a discharge pipe that leads out to the outside, the carbonization furnace has a waste inlet at the top that can be opened and closed by a lid, an oxygen concentration meter for the furnace atmosphere on the furnace shell peripheral wall, and a furnace bottom peripheral wall. The combustion nozzle is provided in the part, the ignition burner is provided in the upper part, the furnace bottom thermometer is further provided in the upper part, and the supply amount of the combustion supporting gas to the blowing nozzle is adjusted by the detection value of the oxygen concentration meter. The present invention provides a dry distillation incineration apparatus for organic solvent-containing waste, wherein a control mechanism is provided.

The organic solvent-containing waste to be treated according to the present invention includes paints, printing inks, adhesives, oil and fat detergents containing volatile, flammable organic solvents such as methanol, ethyl acetate, methyl ethyl ketone, and toluene. And waste such as impregnated matter adhered thereto, which can be treated while being sealed in a metal can or the like. The organic solvent contained in the waste must be completely vaporized while the combustion of the flammable solids and the dry distillation are stably continued. More than three times the flammable solids were required in ratio. Therefore, organic solvent-containing waste is usually
Along with other combustible solid wastes such as paper, wood, plastic, etc., they are put into a carbonization furnace and deposited for carbonization, but at that time, other combustible solid wastes are used as the lower layer, and organic solvent-containing wastes are placed on top. It is desirable that the material is charged so as to form a material layer.

Conventionally, when the oxygen concentration becomes 10% or more in a mixed gas atmosphere of an organic solvent vapor and air, and the oxygen concentration becomes 5% or more in a mixed gas atmosphere of hydrogen, carbon monoxide gas and air, explosiveness is caused. It is known that the combustion of gas is caused and that the oxygen concentration is reduced by adding an inert gas to the air-fuel mixture in order to prevent the combustion (Showa 61
August 15, 2008, published by the Japan Society of Safety Engineering, "Safety Engineering, Vol.
25, no. 4, p194-205 "). The present invention makes it possible to carry out the treatment step safely and efficiently by skillfully incorporating the above knowledge conditions into the dry distillation incineration treatment conditions for organic solvent-containing waste.

[0010]

In the dry distillation incineration method according to the present invention, in the first stage, the atmosphere in the dry distillation furnace is replaced with an inert gas and the atmosphere in the furnace is previously burnt with organic solvent vapor before the organic solvent-containing waste is charged. By setting the oxygen concentration to be equal to or less than the limit oxygen concentration, even if any ignition conditions occur during the charging process of the waste containing organic solvent, there is no ignition explosion. The next step is started smoothly with the internal atmosphere having a lower oxygen concentration.

In the second stage, a mixture of air and an inert gas adjusted to a level below the combustion limit oxygen concentration of the organic solvent vapor is supplied as a supporting gas by igniting a part of the lower layer of the deposited waste. As a result, a stable combustion oxide layer can be formed by sequentially expanding the ignited combustion portion over the entire lower layer of the deposited waste, and in this process, the atmosphere in the furnace is an organic solvent vapor and hydrogen and monoxide generated by partial carbonization. Although flammable decomposition gas such as carbon is present, the oxygen concentration in the atmosphere further decreases, and does not exceed the combustion limit oxygen concentration in the atmosphere. Can be transferred to

The third step is to mix the inert gas with the air in the supporting gas supplied in the second step in order to promote the dry distillation while maintaining a stable combustion oxide layer below the sedimentary waste. The amount is gradually reduced, and only air is finally supplied. The supply amount is the amount of organic solvent vapor in the carbonization furnace and the carbonized gas containing more flammable hydrogen and carbon monoxide gas. The oxygen concentration in the mixed atmosphere is adjusted so as not to exceed the combustion limit of the atmosphere. In this manner, the organic solvent contained in the waste is completely vaporized, and the solid content is subjected to dry distillation and ash combustion to complete incineration. Ash combustion refers to a combustion process in which a large amount of air is supplied to the burned material having a low calorific value after the generation of dry distillation gas and incinerated.

[0013] The dry distillation gas containing the organic solvent and the like generated in the first and second stages is led to a combustion furnace where it is completely burned under a required amount of air supply and discharged out of the processing system as a combustion gas. A part of the exhaust gas can be recycled as an inert gas used in the second and third stages.

The apparatus according to the present invention is suitable for carrying out the above-mentioned method for dry distillation and incineration of organic solvent-containing waste, and comprises a dry distillation furnace, a combustion tube, a combustion furnace and an exhaust pipe as main equipment. In the treatment device, mainly by measuring the oxygen concentration in the furnace atmosphere of the carbonization furnace and the input of waste related thereto and control of the carbonization process, it is a device that prevents explosion in the furnace and enables smooth operation, The specific conditions will be clarified by the description of the following embodiment.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a case of carrying out the method of dry distillation incineration of organic solvent-containing waste of the present invention using an embodiment apparatus shown in the explanatory diagram of FIG. 1 will be described. In FIG. 1, 1 is a carbonization furnace, 2 is a combustion furnace, 3 is a combustion cylinder, 4 is a dust collector, 5 is a main exhaust fan, and 6 is a stack. Carbonization furnace 1
Has a waste inlet 14 that can be opened and closed by a water seal lid 15 at the furnace top, a furnace bottom that has an inverted conical peripheral wall, and a lower end that can be opened and closed by an ash dumper 22. Has become. An oxygen concentration meter 30 for the atmosphere in the furnace is provided at the upper, middle, and lower portions of the furnace body, respectively. The inverted conical peripheral wall at the bottom of the furnace has a peripheral wall close to the ash outlet at the lower end thereof. Sixteen combustible gas injection nozzles 12 at equal positions on the circumference, one ignition burner 11 above, and four thermocouple type furnaces at positions above the peripheral wall that divide the peripheral wall into four equal parts. A bottom thermometer 13 is provided.

The combustion cylinder 3 is provided in the middle of a carbonization gas line 40 connecting the carbonization furnace 1 and the combustion furnace 2, and a preheating burner 17 is provided on a gas inflow side thereof, and an air supply blower 9 is provided on a gas outflow side thereof. The gas inflow side is connected to the carbonization furnace 1 via the carbonization gas outflow valve 8, and the gas outflow side is connected to the combustion furnace 2 as a combustion unit. The combustion furnace 2 communicates with the outside air through an exhaust pipe 41 that reaches the stack 6 via a dust collecting device 4 and a main exhaust fan 5, and is capable of discharging combustion gas.

Reference numeral 42 denotes a recirculation line for the combustion gas which branches off from the discharge line 41 on the inflow side of the main exhaust fan 5 and is connected to the blowing nozzle 12 of the carbonization furnace 1. Gas valve 43, branched air inflow valve 4
4. Gas cooler 45, oxygen concentration meter 46, air blower 1
0, a flow control valve 20, and a flow meter 21 are sequentially provided. 4
Reference numeral 7 denotes a drain receiver from the gas cooler 45. The flow meter 21 measures the amount of recirculated gas, and the controller 18
Is compared with the set value, and the amount of recirculated gas is adjusted by controlling the speed of the air blower 10. Further, the controller 18 adjusts the opening degree of the flow control valve 20 and the speed of the air blower 10 in preference to the flow control of the air blower 10 according to the detection value of the oxygen concentration meter 30 of the carbonization furnace 1. Then, the amount of recirculated gas is reduced, and the gas flow is stopped.

Further, the dry distillation gas outlet valve 8 is used to be fully closed when the dry distillation furnace 1 is replaced with an inert gas, and it is preferable to improve the airtightness. The recirculation gas valve 43 of the recirculation line 42 is fully opened when the combustion gas is sent to the dry distillation furnace 1 as an inert gas, and fully closed otherwise. Further, the air inflow valve 44 is opened and closed in conjunction with the measured value of the oxygen concentration meter 46 of the reflux gas in the reflux line 42 so as to maintain the oxygen concentration of the reflux gas within the set value range. . Above main exhaust fan 5, air supply blower 9, air supply blower 10
Operation control, valve opening / closing control of the carbonization gas outflow valve 8 and the recirculation gas valve 43, operation stop control of the ignition burner 11, the preheating burner 17, and operation of the furnace bottom thermometer 13, the oxygen concentration meters 30 and 46 are electrically or electrically controlled. It is desirable to perform centralized management by pneumatic remote control means.

The dry distillation incineration of organic solvent-containing waste by the above-described apparatus is performed according to the following procedure. First, the carbonization gas outflow valve 8 is closed, the preheating burner 17 of the combustion cylinder 3 is refueled and ignited, the main exhaust fan 5 is started, and a slight excess of air is supplied to the preheating burner 17 to complete combustion to complete the combustion furnace. 2 is preheated, and the combustion gas having an oxygen concentration of 5% or less is dust-removed by the dust collector 4, is taken in by the main exhaust fan 5 through the exhaust pipe 41, and is discharged from the stack 6 to the outside air.

On the other hand, the dry distillation furnace 1 is provided with a reflux gas valve 43 and a flow control valve 2 of a reflux pipe 42 branched from the combustion gas discharge pipe 41 of the combustion furnace 2 under the opening of the inlet 14 at the top.
0 is fully opened, the air blower 10 is started, and a part of the combustion gas is discharged from the discharge line 41 through the gas cooler 45.
The temperature is lowered to not more than 0 ° C., and the gas is sent from the blowing nozzle 12 into the dry distillation furnace 1 and flows out of the furnace through the inlet 14 at the furnace top to the outside air together with the air in the furnace. Then, flammable wastes such as paper, wood, plastics, garbage and the like which do not contain the organic solvent are charged and deposited into the furnace from the inlet 14 before or during the replacement of the atmosphere in the furnace with the inert gas. The measurement by the oxygen concentration meter 30 arranged in the upper, middle and lower portions of the furnace body is started.

With the progress of the gas replacement, when all of the upper, middle, and lower oxygen concentration meters 30 have reached the detection value of 10% or less, the waste containing the organic solvent, the impregnated adhering matter thereof, or these are accommodated. A sealing can is inserted and deposited on the other flammable waste deposit layer, and the loading of waste is completed. At the same time, the loading port 14 is closed with a lid 15 in a water-tight manner to prevent the outside air from flowing into the furnace. The water ring type purge valve 16 is fully opened under shutoff, and when the oxygen concentration in the furnace reaches 5% due to ventilation and outflow from the purge valve 16, the purge valve 16 is closed, and the air supply blower 10 is stopped. The first stage ends.

Next, the opening of the dry distillation gas outflow valve 8, the ignition of the ignition burner 11, and the restart of the operation of the air blower 10 are performed almost simultaneously, and the air inflow valve 44 of the recirculation line 42 is gradually opened to reduce the oxygen. The detected value of the concentration meter 46 is maintained at approximately 10%, and the amount of air blown by the air-fuel mixture is controlled by the speed control of the air blower 10 and the valve opening degree control of the flow control valve 20 for the atmosphere in the dry distillation furnace 1. Each of the oxygen concentration meters 30 is controlled so as to maintain the oxygen concentration of 5% or less, and the combustion oxide layer ignited in a part of the lower layer of the sedimentary waste is expanded and grown on the entire lower layer. End the stage.

Whether or not a combustion oxide layer was formed on the entire lower layer of the above-mentioned sediment waste was determined by all four furnace bottom thermometers 13 distributed on the furnace body above the ignition burner 11 by about 200.
The temperature can be detected by indicating a detection temperature of not less than ℃, and the carbonization gas including the organic solvent vapor and the combustible gas such as hydrogen and carbon monoxide gas generated by pyrolysis during this period is completely burned in the combustion furnace 2. On the other hand, the preheating burner 17 of the combustion cylinder 3 is stopped during this time, the air supply blower 9 continues to supply air, and a part of the combustion gas is blown through the recirculation line 42 at an oxygen concentration of about 10%. It is sent to the nozzle 12 and is mostly discharged from the stack 6 to the outside air.

When a stable combustion oxide layer is formed on the entire lower surface of the deposited waste in the dry distillation furnace 1, the valve opening of the air inlet valve 44 of the return line 42 is gradually increased (return gas valve 43).
Is controlled to be only fully opened and fully closed.) The oxygen concentration in the recirculation gas to the blowing nozzle 12 is increased, and finally the recirculation gas valve 43
Is closed and only air is supplied (the oximeter 46 during this time).
Is set so that the oxygen concentration is increased stepwise from the oxygen concentration of about 10% in the second step to the oxygen concentration of 20.9% in the third step). The dry distillation gas atmosphere in the furnace is measured by an oxygen concentration meter 30 so that the oxygen concentration does not become 5% or more, and the flow rate control valve 20 is controlled to maintain the oxygen concentration.
Stable carbonization is continued, the incineration process is completed through carbonization combustion through ash combustion, and the third stage is completed.
Non-combustible materials such as metal cans open the ash dumper 22 and are discharged out of the furnace to complete the process.

In the second and third stages, the oxygen concentration in the atmosphere in the dry distillation furnace 1 causes the inflow of outside air due to failure of the lid 15 of the inlet 14, the ash-out damper 22, the furnace wall, and the like. Occurred and increased to 6% or more.
If detected, the air blower 10 is stopped to prevent an accident. In the present embodiment, three oxygen concentration meters 30 are provided in the furnace body of the dry distillation furnace 1 in the upper, middle and lower parts, one ignition burner 11 is provided on the furnace bottom peripheral wall, and 16 blowing nozzles 12 are provided.
Although the case where four pieces and four furnace bottom thermometers 13 are used is shown, it is needless to say that the number may be increased or decreased depending on design conditions, operation conditions and the like.

[0026]

As described above, according to the present invention,
Regardless of the state of the waste containing organic solvents, the atmosphere in the furnace is changed to the desired inert gas and the ratio of the inert gas in the combustion supporting gas is adjusted throughout the entire process from input deposition in the carbonization furnace to ignition carbonization incineration. By maintaining conditions that do not exceed the combustion limit oxygen concentration of organic solvent vapor or a mixture of organic solvent vapor and dry distillation gas, explosive combustion is completely prevented,
Organic solvent-containing waste and other flammable waste can be treated at once, and organic solvent-containing waste can be treated in a sealed state, thus improving the efficiency of dry distillation incineration. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 carbonization furnace 2 combustion furnace 3 combustion cylinder 5 main exhaust fan 8 carbonization gas outflow valve 9 air supply blower 10 air supply blower 11 ignition burner 12 blow nozzle 13 furnace bottom thermometer 14 inlet 15 lid 17 preheating burner 18 controller 20 flow rate adjustment Valve 21 Flow meter 30 Oxygen concentration meter 40 Dry distillation gas line 41 Discharge line 42 Reflux line 43 Reflux gas valve 44 Air inflow valve 46 Oxygen concentration meter

Continuation of the front page (56) References JP-A-5-141639 (JP, A) JP-A-60-144512 (JP, A) JP-A-3-137407 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) B09B 3/00 F23G 5/027 F23G 5/24 F23G 5/50 F23G 7/00

Claims (7)

(57) [Claims] In a method for dry-burning incineration of organic solvent-containing waste, air in a dry-burning furnace is replaced with an inert gas so that the furnace atmosphere is reduced to a combustion limit oxygen concentration of organic solvent vapor or less. The organic solvent-containing waste is charged and deposited in the first stage, and the inert gas is further fed in to lower the oxygen concentration in the furnace atmosphere, and the lower part of the deposited waste is ignited to ignite a part thereof. A second stage in which a mixture of air and an inert gas having a combustion limit oxygen concentration of an organic solvent vapor is supplied to form a combustion oxide layer on the entire lower layer of the deposited waste to start dry distillation of the upper layer waste; The oxygen concentration in the carbonized gas containing the organic solvent vapor to be maintained, the mixing ratio of the inert gas in the supplied gaseous mixture is gradually reduced and the supply amount is adjusted so as to maintain the oxygen concentration in the carbonized gas below the combustion limit of the carbonized gas, Ultimately, stable air distillation is continued by supplying only air And a third stage in which incineration is completed after ash combustion, and the carbonization gas generated in the second and third stages is guided to a combustion furnace to be completely burned. Dry distillation incineration method. 2. An exhaust gas obtained by burning fuel in a combustion furnace as an inert gas used in the first stage, and burning the dry distillation gas as an inert gas of an air-fuel mixture used in the second and third stages. The dry distillation incineration method of an organic solvent-containing waste according to claim 1, wherein the exhaust gas burned in the furnace is used. 3. The method of claim 1, wherein nitrogen gas or carbon dioxide gas supplied from a separate gas source is used as the inert gas used in the first step of the first step. 4. An inflammable waste containing no organic solvent is charged and deposited in the furnace prior to the introduction of the organic solvent-containing waste before or during the inert gas replacement step in the dry distillation furnace. 2. A method for dry distillation and incineration of organic solvent-containing waste according to claim 1. 5. Combustion from a carbonization furnace (1), a combustion furnace (2), a combustion cylinder (3) provided in a carbonization gas pipe (40) connecting the two furnaces, and a combustion furnace (2). In a waste carbonization incinerator having a discharge pipe (41) for discharging exhaust gas to the outside, a carbonization furnace (1) has a waste inlet (14) which can be opened and closed by a lid (15) at the top, and a furnace body. An oxygen concentration meter (30) for the atmosphere in the furnace is provided on the peripheral wall, a combustion supporting gas injection nozzle (12) is provided on the peripheral wall of the furnace bottom, and an ignition burner (1) is provided above the furnace.
1) A controller (18) which further includes a furnace bottom thermometer (13) on the top thereof and adjusts the supply amount of the combustion supporting gas to the blowing nozzle (12) based on the detection value of the oxygen concentration meter (30). An incinerator for dry distillation of organic solvent-containing waste, comprising: 6. A blowing nozzle (1) of a carbonization furnace (1) that branches off from a discharge line (41) of a combustion exhaust gas of a combustion furnace (2).
A reflux pipe (42) communicating with 2) is provided, and the reflux pipe (42) is provided with a reflux gas valve (4) sequentially in the gas flow direction.
3) and an air inlet valve (44) branched from the pipe, a cooler (45), and an oximeter (4) for the flowing gas in the pipe.
6), an air blower (10), a flow control valve (20), and a flow meter (21) are provided, and the flow control valve (20) and the air blower (10) are provided by an oxygen provided in a carbonization furnace (1). 6. The incineration treatment apparatus for organic solvent-containing waste according to claim 5, wherein the valve opening and the blower operation speed are adjusted by a controller (18) related to the detected value of the concentration meter (30). 7. An oxygen concentration meter (46) in a reflux line (42).
7. The incineration treatment apparatus for incineration of organic solvent-containing waste according to claim 6, further comprising means for adjusting the degree of opening of the air introduction valve (44) based on the detected value.