JPH0861647A - Method for burning organic chloride - Google Patents

Abstract

PURPOSE: To reduce the amount of chlorine gas generated by combustion by a method wherein the amount of air used for burning organic chloride is set to be lower than that of the prior art and its mol ratio is of a specified time with respect to a theoretical amount of air. CONSTITUTION: Organic chloride A is supplied into an incinerator 1 together with air B as required under its atmoized state and at the same time the air B is supplied through an air flow rate adjusting valve 2 and then ignition is carried out. In the case that a combustion temperature is adjusted, water, water vapor or hydrochloric acid C are supplied into the incinerator 1 together with the air B as required Combustion discharged gas D discharged from the incinerator 1 upon completion of combustion is fed into a cooling tower 3 and cooled with a heat exchanger 4. Then, the gas is fed into an absorbing tower 5, contacted with water E there and hydrogen chloride is absorbed and removed. In this case, an air supplying amount is set to have a range of about 0.8 to 1.15 times in a mole ratio in respect the to a theoretical amount of air, thereby it is possible to reduce m amount of generated cholrine gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for incinerating organic chlorine compounds which can reduce the generation of harmful chlorine gas as much as possible.

[0002]

2. Description of the Related Art In the chlorine derivative industry and the like, an organic chlorine compound is produced as an undesired by-product, and this by-product organic chlorine compound is often incinerated. In this incineration process, combustion is performed in the presence of a large excess of air so that the carbon atoms contained in the organic chlorine compound are completely converted to carbon dioxide. In such a combustion reaction, the carbon atoms contained in the organic chlorine compound are completely converted to carbon dioxide, the chlorine atoms are combined with hydrogen atoms to be converted into hydrogen chloride, and a small amount of chlorine atoms which are not combined with hydrogen atoms. Is converted into molecular chlorine gas, and hydrogen atoms that have not been combined with chlorine gas are converted into water. Therefore, the flue gas usually contains nitrogen, oxygen, water vapor, hydrogen chloride, and a small amount of chlorine gas in addition to carbon dioxide. Such combustion exhaust gas, after cooling, is guided to the absorption tower, after hydrogen chloride is absorbed and removed with water, is further guided to the detoxification tower sodium chloride is absorbed and removed by alkali such as sodium sulfite, caustic soda, It is completely detoxified and released into the atmosphere.

By the way, chlorine in combustion exhaust gas is not only regulated as a harmful substance but its emission is also used in the inner walls of absorption towers and detoxification towers to prevent erosion of equipment by hydrogen chloride. Since it has a property of deteriorating reinforced plastics (FRP) such as epoxy resin and vinyl ester resin, it is desired to reduce the generation of chlorine gas in an incinerator.

As a method of suppressing the generation of such chlorine gas, it is known to increase the combustion temperature,
For this reason, a large excess of air is supplied to the organic chlorine compound to incinerate it at a high combustion temperature. Specifically, all the carbon atoms of the organic chlorine compound to be incinerated are converted into carbon dioxide, and all the chlorine atoms are burned. Is converted into hydrogen chloride, and a large excess of air of about 1.3 to 1.6 times in molar ratio with respect to the theoretical air amount necessary for converting all the hydrogen atoms remaining after hydrogen chloride generation into water. The method of incinerating an organic chlorine compound in the temperature range of 1300 to 1600 ° C. in the presence is adopted.

However, even when this method is used, the amount of chlorine gas contained in the combustion exhaust gas is 50 to 200.
It is volppm, which is not a sufficiently satisfactory level.

In this case, it is possible to carry out the combustion reaction in a higher temperature region in the presence of a large excess of air, but the maximum temperature at which the refractory brick used in the combustion furnace is not damaged is about 1600 to 1700 ° C ( Therefore, there is a limit to increase the combustion reaction temperature.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for incinerating an organic chlorine compound which can suppress the amount of chlorine generated as much as possible and is economically advantageous.

[0008]

As a result of earnest studies to achieve the above object, the present inventor has found that the amount of air for burning the organic chlorine compound is much lower than the conventional amount, and is almost the same as the theoretical amount of air. Therefore, we obtained new knowledge that the amount of chlorine gas generated by combustion is dramatically reduced.

[0009] That is, in the conventional incineration technique, a large amount of excess air (excess of oxygen) is used for complete combustion of organic substances and adjustment of the temperature in the furnace. About 3 to 1.6 times as much air is supplied to the incinerator together with the organic chlorine compound, but the present inventor has found that the air supply amount is in the range of 0.8 to 1.15 times the theoretical air amount in a molar ratio. As a result, the amount of chlorine gas produced is small, usually 10v
It has been found that it is possible to incinerate an organic chlorine compound at an olppm or less.

Combustion in the low air ratio range is
Combustion becomes unstable when the supply amount and composition of the organochlorine compound change, and as a result of studying a method for maintaining stable combustion, carbon monoxide was contained in the combustion exhaust gas in the low air ratio range. Is generated, and there is a correlation between the amount of carbon monoxide and the amount of chlorine gas produced, the amount of carbon monoxide contained in the combustion exhaust gas is measured, and the amount of chlorine gas produced based on the measurement result is calculated. Therefore, it was found that the amount of chlorine gas produced can be adjusted to an extremely low amount by adjusting the amount of air supplied from the measurement result of carbon monoxide, and the present invention has been completed. It is a thing.

Therefore, according to the present invention, (1) in a method of incinerating an organic chlorine compound by supplying the organic chlorine compound and air to the incinerator, the amount of air supplied to the incinerator is supplied to the incinerator. Required to convert all carbon atoms of organochlorine compounds and hydrocarbons to carbon dioxide, and all chlorine atoms to hydrogen chloride, and all hydrogen atoms remaining after hydrogen chloride formation to water A method for incinerating an organic chlorine compound, characterized in that the molar ratio is 0.8 to 1.15 times the theoretical air amount, and (2) supplying an organic chlorine compound and air to an incinerator to produce an organic chlorine. In the method for incinerating a compound, the concentration of carbon monoxide contained in the combustion exhaust gas after incineration of the organic chlorine compound is measured, and the amount of air supplied to the incinerator is adjusted based on the measurement result. Incineration of chlorine compounds Method and (3) a method of incinerating an organic chlorine compound by supplying an organic chlorine compound and air to an incinerator, after removing hydrogen chloride gas contained in the combustion exhaust gas after incineration of the organic chlorine compound, Organic chlorine characterized by continuously measuring the concentration of carbon monoxide in the flue gas from which this hydrogen chloride gas has been removed and automatically controlling the amount of air supplied to the incinerator based on the measurement results A method of incinerating a compound is provided.

The present invention will be described in more detail below. In the method for incinerating an organic chlorine compound of the present invention, as described above, the amount of air supplied is much smaller than that in the conventional case when incinerating an organic chlorine compound.

In the present invention, examples of the organic chlorine compound to be incinerated include methyl chloride, methylene chloride,
Chlorine of aliphatic saturated hydrocarbons such as chloroform, carbon tetrachloride, ethyl chloride, ethane dichloride, trichloroethane, tetrachloroethane, pentachloroethane, perchloroethane, propyl chloride, propane dichloride, propane trichloride, butyl chloride, butane dichloride. Chlorides, chlorinated products of aliphatic unsaturated hydrocarbons such as vinyl chloride, vinylidene chloride, trichloroethylene, perchloroethylene, propylene chloride and chloroprene, or oxygen-containing organic compounds such as chloral and 2-chloroethanol, and polyvinyl chloride, Examples thereof include organic polymer compounds such as polyvinylidene chloride and chloroprene rubber, and these can be supplied to an incinerator alone or in combination. In this case, the amount of chlorine contained in the organic chlorine compound can be in the range of 10 to 95% by weight. The organochlorine compound may be supplied in any form of solid, liquid and gas, and when supplied in liquid form, it is usually sprayed with air or steam. When the organic chlorine compound is difficult to burn, hydrocarbons having 1 to 4 carbon atoms such as methane, ethane and propane may be supplied to the incinerator as auxiliary fuel. Even when supplying hydrocarbons having 1 to 4 carbon atoms such as methane, ethane and propane as auxiliary fuels to the incinerator, all carbon atoms of the organic chlorine compounds and hydrocarbons supplied to the incinerator are converted to carbon dioxide. Then, all the chlorine atoms are converted to hydrogen chloride, and further, all the hydrogen atoms remaining after the generation of hydrogen chloride are converted to water in a molar ratio of 0.8 to 1. A 15-fold amount of air is supplied to the incinerator.

In the present invention, the amount of air for burning the organochlorine compound is set to a much lower air ratio than in the past, and specifically, the molar ratio to the theoretical air amount is 0.8 to 0.8.
The range is 1.15 times, preferably 0.9 to 1.1, and more preferably 0.98 to 1.05. If the air ratio is too high, chlorine generation cannot be sufficiently suppressed,
The object of the present invention cannot be achieved. On the other hand, if it is too low, combustion itself may become unstable, or undecomposed organic chlorine compounds may remain and pollute the downstream. In this case, the theoretical amount of air means that all the carbon atoms supplied to the incinerator are converted to carbon dioxide, all the chlorine atoms are converted to hydrogen chloride, and all the hydrogen atoms remaining after the generation of hydrogen chloride. Is the amount of air required to convert water to water.

The combustion temperature in the incinerator can be set as usual, specifically in the range of 700 to 1600 ° C. If the combustion temperature is lower than 700 ° C, it may be difficult to maintain the flame and the organic chlorine compound may not be completely decomposed. On the other hand, if it exceeds 1600 ° C, the refractory bricks forming the inner wall of the incinerator may be easily damaged. The preferred combustion temperature is 1000 to 1600 ° C, more preferably 1200 to
It is in the range of 1600 ° C. Incidentally, in the combustion in the low range of the air ratio, which is a feature of the present invention, the relationship between the chlorine concentration to be generated and the temperature shows an inverse relationship to the conventional knowledge calculated from the equilibrium constant of the Deacon reaction, The chlorine concentration tends to decrease as the temperature decreases.

Further, in the conventional method of incineration with excessive air,
Adjustment of the temperature in the furnace is performed by increasing or decreasing the amount of air supplied, but in the incinerator method of the present invention, the amount of air supplied to the incinerator is controlled for the purpose of suppressing chlorine generation. The internal temperature may exceed 1600 ° C. Therefore, it is desirable to control the furnace temperature. As a method for controlling the furnace temperature, a method of supplying water, steam or hydrochloric acid (for example, water obtained by absorbing hydrogen chloride from the incinerator) into the incinerator and maintaining the furnace temperature is suitable.
In this case, in order to prevent damage due to thermal shock resulting from rapid thermal cooling of the furnace wall, it is preferable to spray water or hydrochloric acid with air or steam and introduce it into the incinerator.

The flue gas produced by burning the organic chlorine compound at a predetermined air ratio as described above generally has a chlorine gas content of 10 depending on the nature of the organic chlorine compound and the amount of air supplied.
The amount of chlorine gas is suppressed to less than the capacity ppm, usually 0.01 to 2 volume ppm, and more preferably 0.01 to 0.3 volume ppm, and compared to the conventional amount of 50 to 200 volume ppm, chlorine gas is generated significantly. Small quantity.

Further, the combustion exhaust gas burned under such conditions is characterized in that it contains some carbon monoxide. As described above, this carbon monoxide serves as a guide for the combustion conditions in the present invention, and is 0.01 to 5% by volume, preferably 0.02 to 2% by volume, and most preferably 0.1 to 1% by volume. It is desirable to control the amount of air so that the carbon monoxide concentration is in the range of%. That is, when the concentration of carbon monoxide is less than 0.01% by volume, the amount of chlorine produced in the combustion exhaust gas increases, and when the amount of supplied air is reduced and exceeds 5% by volume, it is difficult to maintain combustion. Therefore, it is desirable to increase the supply air amount.

The combustion exhaust gas discharged from the incinerator after the organic chlorine compound is incinerated as described above is introduced into a cooling tower and cooled in the same manner as usual, and then hydrogen chloride is absorbed by water in the absorption tower, and then, If necessary, residual chlorine gas can be removed in the abatement tower. As described above, since a small amount of carbon monoxide is contained, before being released into the atmosphere, a flare stack, a catalytic combustion reactor, or the like is used to measure 700 to 1
It is effective to incinerate with a large excess of air at a combustion temperature of about 100 ° C. With this method, most of the chlorine atoms have already been absorbed as hydrogen chloride, so chlorine gas will not be generated even if there is a large excess of air, and the combustion products released to the atmosphere are carbon dioxide and water. Only, it is possible to emit completely detoxified combustion exhaust gas.

Next, the incineration method of the organic chlorine compound of the present invention will be specifically described with reference to FIG.

FIG. 1 is a flow chart showing an example of the incineration method of the present invention. In the incinerator 1, an organochlorine compound A is supplied in a spray state together with air B as necessary, and the air B is adjusted in air flow rate. It is supplied to the incinerator 1 via the valve 2 and the incinerator 1
The above-mentioned combustion is performed. When adjusting the combustion temperature, water, steam or hydrochloric acid C is supplied to the incinerator 1 together with air B as necessary. The combustion exhaust gas D which has been burned and discharged from the incinerator 1 is introduced into the cooling tower 3, where it is cooled to about 50 to 120 ° C. with water circulating in the heat exchanger 4. The combustion exhaust gas D that has left the cooling tower 3 is then introduced into the absorption tower 5, where it contacts the water E and hydrogen chloride is absorbed and removed. Flue gas D ₁ from which hydrogen chloride has been removed in the absorption tower 5
Is further introduced into the detoxification tower 6, where chlorine is absorbed by contacting with the alkaline water F. The combustion exhaust gas D ₂ from which chlorine has been removed in the detoxification tower 6 is finally re-combusted in the catalytic combustion reactor 7 and released into the atmosphere as harmless combustion exhaust gas D ₃ from which carbon monoxide has been removed.

In the pipe through which the combustion exhaust gas D ₂ between the abatement tower 6 and the catalytic combustion reactor 7 of this incinerator passes, the concentration of carbon monoxide in the combustion exhaust gas D ₂ can be continuously measured. A carbon detector (infrared spectrophotometer) 8 is installed.
Further, a control device 9 for sending a signal for controlling the air flow rate control valve 2 so as to keep the carbon monoxide concentration detected by the detector 8 at the above-mentioned constant value is provided, and if the amount of carbon monoxide decreases, the air The air flow rate control valve 2 is controlled so that the flow rate is decreased and the air flow rate is increased when the carbon monoxide concentration is increased, so that even if the amount or composition of the organochlorine compound A varies. The combustion can be stably maintained, and continuous automatic incineration operation can be performed. In addition, incinerator 1
A pipe 10 through which the combustion exhaust gas D passes between the cooling tower 3 and the cooling tower 3 is provided with an outlet 10 for extracting the exhaust gas. The air flow rate can be controlled as necessary by using the organochlorine compound B.
When water, water vapor, or hydrochloric acid C is sent together with air, it can also be performed for the air flow rate control valves 11 and 12.

In the incinerator, the carbon monoxide detector was used to measure the concentration of carbon monoxide in the combustion exhaust gas discharged from the detoxification tower, but the carbon monoxide detector was used to measure the concentration of carbon monoxide emitted from the incinerator. Extraction port 10 for carbon monoxide in exhaust gas
It may be taken out from the device, measured and controlled.
Since this exhaust gas contains hydrogen chloride gas and chlorine gas, it may damage the carbon monoxide measuring device. From this point, measure the carbon monoxide concentration in the exhaust gas flowing out from the abatement tower 6 as shown in the figure. However, it is recommended to control.

The adjustment and control of the air amount can also be performed by directly measuring the chlorine gas concentration in the exhaust gas. In this case, continuous chlorine gas analyzers include the diaphragm electrolytic electrode method and the O-tolidine continuous absorption spectrophotometric method. However, in both cases, when a high concentration of chlorine gas is detected, the subsequent analysis value is likely to cause a positive error. It has characteristics and is not suitable as an analyzer for the purpose of continuous control.

[0025]

According to the incineration method of an organic chlorine compound of the present invention, the generation of chlorine is reduced as much as possible by incinerating the organic chlorine compound by setting the air amount to a specified low amount. it can.

Further, according to the method for incinerating an organic chlorine compound of the present invention, by keeping the concentration of carbon monoxide in the combustion exhaust gas within a certain range, the generation of chlorine is reduced as much as possible, and the combustion is stably maintained. it can.

[0027]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to the following examples.

Example 1 A mixture of chlorinated hydrocarbons mainly having 1 to 4 carbon atoms (63% chlorine by weight, 33% carbon by weight,
(Containing 4% hydrogen) was continuously incinerated at 88 kg per hour.

Empty the chlorinated hydrocarbon mixture in an incinerator.
Qi (15M³ / Hr, 0 ° C 1 atm)
And supply air to achieve the air ratio shown in Table 1.
In order to maintain the temperature inside the furnace at about 1500 ° C, 20
% Hydrochloric acid at a rate of 66 kg per hour in air (15 M³ /
It was supplied by spraying together with (hr, 0 ° C., 1 atm). Incinerator
The residence time of the combustion exhaust gas is 1.1 to 1.3 seconds.

The flue gas discharged from the incinerator is then cooled in a cooling tower, hydrogen chloride is absorbed and removed in an absorption tower, chlorine remaining in the detoxification tower is removed, and finally, a large amount is removed in a catalytic combustion reactor. The carbon monoxide remaining under excess air was incinerated and released to the atmosphere.

The carbon monoxide concentration (denoted by A in the table) in the combustion exhaust gas from the incinerator was measured by the following method. Also,
Carbon monoxide concentration in the combustion exhaust gas from the abatement tower (B in the table)
Was displayed with an infrared spectrophotometer. Therefore, the carbon monoxide concentration (B) indicates the concentration in the combustion exhaust gas after absorbing the hydrogen chloride gas. <Chlorine concentration> In the figure, the combustion exhaust gas was taken out through the take-out port 10, and the concentration of chlorine contained in the taken-out combustion exhaust gas was measured by O-tolidine absorption spectrophotometry. <Carbon monoxide concentration A> In the figure, the combustion exhaust gas was taken out through the outlet 10, and the concentration of carbon monoxide contained in the taken out combustion exhaust gas was measured by a gas chromatography method. <Carbon monoxide concentration B> Carbon monoxide contained in the combustion exhaust gas discharged from the abatement tower by the carbon monoxide detection device (infrared spectrophotometer) 8 taken out from the combustion exhaust gas discharged from the abatement tower Was measured.

Table 1 shows the measurement results of the concentration of chlorine gas produced by incineration and the concentration of carbon monoxide for each air ratio. The air ratio is the oxygen concentration in the air, which is 2
It was calculated by measuring the total amount of air supplied to the incinerator including atomized air as 0.6% by volume.

[0033]

[Table 1]

[Example 2] The air ratio was set to 1.03, and the temperature of the inner wall of the incinerator was adjusted to the temperature shown in Table 2.
The same chlorinated hydrocarbon mixture was incinerated under the same conditions as in Example 1 except that the supply amount of 0% hydrochloric acid was changed. The results are also shown in Table 2.

[0035]

[Table 2]

[Brief description of drawings]

FIG. 1 is a process diagram showing an incineration method for an organic chlorine compound of the present invention.

[Explanation of symbols]

A Organochlorine compound B Air C Water, steam or hydrochloric acid D, D ₁ , D ₂ , D ₃ Combustion exhaust gas E Water F Alkaline water 1 Incinerator 2 Air quantity control valve 3 Cooling tower 5 Absorption tower 6 Exclusion tower 7 Contact Combustion reactor 8 Carbon monoxide detector 9 Controller

Claims (5)

[Claims] 1. In a method for incinerating an organic chlorine compound by supplying the organic chlorine compound and air to an incinerator, the amount of air supplied to the incinerator is the amount of the organic chlorine compound and hydrocarbons supplied to the incinerator. To the theoretical amount of air required to convert all carbon atoms to carbon dioxide, and all chlorine atoms to hydrogen chloride, and further to convert all hydrogen atoms remaining after the production of hydrogen chloride to water, 0.8-1.1 in molar ratio
A method for incinerating an organic chlorine compound, which is characterized by being 5 times. 2. The method for incinerating an organic chlorine compound according to claim 1, wherein water, steam or hydrochloric acid is supplied into the incinerator. 3. The organic chlorine according to claim 1 or 2, wherein after removing the hydrogen chloride gas contained in the combustion exhaust gas after incinerating the organic chlorine compound, the combustion exhaust gas is re-incinerated with air. How to incinerate compounds. 4. A method of incinerating an organochlorine compound by supplying the organochlorine compound and air to an incinerator, wherein the concentration of carbon monoxide contained in the combustion exhaust gas after the incineration of the organochlorine compound is measured and measured. A method for incinerating an organic chlorine compound, which comprises adjusting the amount of air supplied to an incinerator based on the result. 5. A method for incinerating an organic chlorine compound by supplying an organic chlorine compound and air to an incinerator, wherein hydrogen chloride gas contained in combustion exhaust gas after incineration of the organic chlorine compound is removed, and then this chlorine is removed. The concentration of carbon monoxide in the combustion exhaust gas from which hydrogen gas has been removed is continuously measured, and the amount of air supplied to the incinerator is automatically controlled based on the measurement results. Incineration method.