JPH06279769A - Reforming of coal carbonization gas - Google Patents

Abstract

PURPOSE:To provide a most improved process wherein the tar-containing gas produced from a coal carbonization oven is converted into a gas oil by treating the gas at atmospheric pressure by a gas purification equipment, as such, used in a conventional coke oven, an equipment for producing formed coke, etc., in the former stage of the gas refining step. CONSTITUTION:In the course of refining the carbonization gas produced when coal is carbonized, a low-temperature plasma is generated, and the carbonization gas is reformed with this plasma. Alternatively, in the course of refining the tar-containing coke oven gas produced when coal is carbonized, a low- temperature plasma is generated in the carbonization gas after or before being cooled with an ammoniacal liquor to convert higher hydrocarbons such as tar into lower hydrocarbons. Thus, the recovery of gas oil can be markedly increased simply by adding a low-temperature plasma generator to conventional carbonization gas refining equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reforming a dry-distilled gas containing a tar component, which is generated during the carbonization of coal, such as a coke-oven gas generated from a coke oven.

[0002]

2. Description of the Related Art When coal is carbonized, thermal decomposition starts after the release of water, and the volatile components of the coal are discharged as gas and tar, and the coke as a residue mainly composed of carbon is left behind. That is, it is generally well known as a method for producing coke. During this carbonization, a large amount of tar is contained in the coke oven gas due to the generation of gas such as coke oven gas, carbon monoxide, hydrogen, and methane. In addition, the amount of these gases generated increases as the carbonization temperature rises after the start of thermal decomposition, reaches a maximum value at 700 to 800 ° C, and gradually decreases thereafter, and almost ends at 1000 ° C. On the other hand, tar begins to come out at around 300 ° C and reaches 500
Finished at around ℃. Coke oven gas, carbon monoxide, hydrogen, methane, gas oil, etc. obtained by conventional coal carbonization method have been separated and refined by cooling, distillation, solvent absorption, mechanical methods, etc., and their components (yield) Varies depending on the type of coal, the charging status in the carbonization chamber, and the heating pattern during carbonization, and has already been determined when the coke oven exits.

The amounts of tar and light oil generated from an ordinary coke oven and separated and recovered are 3.2% and 1.0%, respectively, based on the weight of coal charged. The amount of diesel generated is relatively high, but it is desirable to use light oil as an important raw material for the chemical industry rather than tar, which has a low utility value. At present, we do not have the technology to realize this. On the other hand, in order to reduce the molecular weight of high molecular weight hydrocarbons and reform it to the amount of light oil, it is generally hydrogenated under conditions of high temperature and high pressure using a catalyst, etc. It is expensive.

[0004]

[Problems to be Solved by the Invention] Deoiling is an eternal theme in Japan, where resources are scarce, and as part of this, possessing technology that can increase the proportion of coal in light oil is an important issue. . The present invention was developed from such a viewpoint, reforms tar with low utility value generated from a conventional coke oven, and attempts to easily convert it into light oil, and more specifically, Using the conventional gas purification equipment in the coke oven as it is, the gas containing the tar component generated from the coke oven in the pre-stage of the gas refining process is processed at atmospheric pressure, and the tar component is mainly converted to light oil. A method for reforming coal carbonization gas is provided.

[0005]

The present inventor diligently studied a method of using the existing coke oven and gas refining equipment as they are, and reforming the tar content contained in the coke oven carbonization gas generated during the carbonization of coal. As a result, it is possible to easily reform the carbonization gas by generating low-temperature plasma in the carbonization gas. Especially, the high carbon hydrocarbons such as tar contained in the carbonization gas are converted to low carbon hydrocarbons (light oil). I found it possible.

That is, the present invention is a method for reforming coal carbonization gas, characterized in that low temperature plasma is generated in the process of purifying carbonization gas produced during coal carbonization, and the carbonization gas is reformed by the plasma. Further, in the process of purifying the coke oven gas containing the tar content generated during the carbonization of coal, low temperature plasma is generated in the carbonization gas cooled with an anhydrous water or in the carbonization gas before the anhydrous cooling, A method for reforming coal carbonization gas, which comprises reforming high carbon hydrocarbons such as tar in a furnace gas into low carbon hydrocarbons.

The present invention mainly focuses on the generation of low-temperature plasma to reform the carbonization gas, and the use of low-temperature plasma has been very recently introduced to plasma chemistry using pulse. These are PPCP (Pulse Corona Induced Plasma Che) which uses nanosecond pulse high voltage.
mical Process-Pulse corona / plasma chemistry), SPCP (Surface Discharge Induce) that uses nanosecond pulse discharge aggregates created by high-frequency creeping discharge
d Plasma Process-creeping discharge plasma chemistry), both of which cause electrons in plasma generated by discharge to collide with neutral molecules and generate highly reactive chemically active species to carry out a desired reaction. is there. In particular, the PPCP method is used in the fields of surface treatment of plastics, purification of combustion exhaust gas from boilers, dust incinerators, engines and the like. In addition, as seen in JP-A-1116091,
There is an example of a method of producing a carbon electrode by imparting hydrophilicity to a carbon substance by a low temperature plasma method, but the field of use is limited. That is, there is no example of reforming coal carbonization gas with plasma.

The present invention utilizes the above PPCP method,
However, although not limited to this, in order to reform the carbonization gas, particularly to convert high carbon hydrocarbons such as tar in the coke oven gas into low carbon hydrocarbons (light oil), the first stage of the gas purification process A low-temperature plasma generator is installed in and the generated gas is plasma-treated to generate radicals.

FIG. 1 shows an example of the processing flow of the present invention.
The coke dry distillation gas generated from the coke oven 1 enters the dry main 3 through the rising pipe 2 and is further conveyed to the gas cleaning system 5 through the gas cooling system 4, and the purified gas is
Guided to the gas holder. The gas entering the drymen 3 has a high temperature of around 800 ° C., and ammonium hydroxide is injected at this portion to cool the gas temperature to around 100 ° C. and remove the tar content contained in the gas. The tar content that is removed is mainly heavy tar, and the tar ratio in the ammonium hydroxide that is removed from the gas is about 50%, and the remaining light tar remains in the gas. After the treatment, this ammonium hydroxide is introduced into the tar cleaning system 5, where tar and ammonium hydroxide are separated and tar is recovered.

The low temperature plasma generator 6 of the present invention is provided in the preceding stage of the cooling system, and the dry distillation gas passing through this device is subjected to low temperature plasma treatment. Conventionally, the gas temperature is 100
Although it is cooled down to around ℃, in the case of the present invention, the amount of safe water to be supplied is adjusted and the dry distillation gas is heated to an appropriate temperature, preferably 200 ° C.
℃ or above. When an electric discharge is generated by plasma-treating the gas generated from a coke oven, each molecule is equally ionized, and reactions such as polymerization occur at the same time, but when the gas temperature is about 200 ° C or higher, hydrocarbons are decomposed. The reaction proceeds in the direction, and the amount of light oil such as benzene, toluene and xylene increases. The high-voltage discharge is a pulse discharge of the milli-nanosecond order, which stably generates glow-corona without arc generation, and does not cause a rise in gas temperature.

The gas thus modified and containing a large amount of light oil is introduced into the gas cooler 4 to lower the temperature, and the remaining light tar is separated, and then the light cleaning system 7 recovers the light oil. It In addition, the light tar remaining in the gas is removed by the gas cooler 4, and is sent to the tar / anhydrous separator 5 to be recovered.

[0012]

EXAMPLE As shown in FIG. 1, a low temperature plasma generator provided on the dry main outlet side of a coke oven gas recovery system was used to apply a voltage between electrodes to discharge the gas, thereby reforming the dry distillation gas. The reformed gas was cooled by a cooler and then introduced into a purifier to separate and collect light oil. Conventionally, the recovery of light oil is 1 per coal charged.
However, according to the method of the present invention, the conventional 1.
Approximately 1.5% reforming separation was made, which is 5 times.

As described above, in the present invention, gas reforming for recovering light oil can be easily carried out, but it is also possible to adjust the gas component after discharge by adjusting the discharge pulse interval and voltage. . The low temperature plasma used in the present invention is not limited to the pulse corona method using a pulsed high voltage, and it goes without saying that it can be implemented by a high frequency creeping discharge method.

[0014]

As described above, according to the present invention, by adding a low temperature plasma generator as a gas reforming equipment to the gas refining equipment of the coal coke distillation equipment such as the conventional coke oven and the forming coke manufacturing equipment, the gas oil It is possible to dramatically increase the recovery rate, and the effect is extremely large.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a processing flow of the present invention.

[Explanation of symbols]

 1: Coke oven 2: Rise pipe 3: Dry main 4: Gas cooler 5: Tar cleaning system 6: Low temperature plasma generator 7: Gas cleaning device 8: Power supply

Claims (3)

[Claims] 1. A method for reforming coal carbonization gas, wherein low temperature plasma is generated in the process of purifying carbonization gas generated during carbonization of coal, and the carbonization gas is reformed by the plasma. 2. In the process of refining a coke oven gas containing a tar component generated during the carbonization of coal, low temperature plasma is generated in the carbonization gas cooled with cheap water to generate a high carbon hydrocarbon such as tar in the gas. A method for reforming coal carbonization gas, which comprises reforming carbon to low carbon. 3. In the process of refining a coke oven gas containing a tar component generated during coal carbonization, low temperature plasma is generated in the carbonization gas to reform high carbon hydrocarbons such as tar in the gas into low carbon. A method of reforming coal carbonization gas, characterized by cooling with cold water.