JPH0441588A - Increase of cog recovery - Google Patents

Abstract

PURPOSE:To recover a polymer waste as a high-calory gas without spoiling the quality of a prepd. coke by decomposing the polymer waste in a reductive atmosphere in a coke oven. CONSTITUTION:COG (coke oven gas) recovery is increased by the following method A or B. In the method A, a polymer waste with a size of 1mm or smaller is compounded and mixed in a charged coal up to the max. amt. of 20% and the mixture is charged in a coke oven and carbonization is performed to obtain a reductively decomposed gas. In the method B, after coal is coabonized in the coke oven, a polymer waste with a size of 2-400mmphi is charged in an upper space of a carbonization chamber out of contact with the atmospheric air, without stopping a generated gas suction system to obtain a reductively decomposed gas.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention introduces polymeric (plastic) waste into a coke oven and decomposes the polymeric waste in a reducing atmosphere, impairing the quality of the coke produced. The present invention relates to a method for increasing the amount of coke oven gas (COG) recovered.

Conventional technology Plastics are indispensable in modern society, and the good moldability of plastics matches the diversification of modern needs, resulting in the production and consumption of large quantities of plastics (polyethylene, polypropylene, styrene,
Approximately 7 million tons of PVC products were produced in 2012).

On the other hand, these plastics are also discharged as industrial waste, and currently they are disposed of in landfills or partially incinerated, but they are not decomposed by bacteria in the soil.
When incinerated, it poses problems in terms of exhaust gas treatment and the large calorific value that adversely affects the incinerator.

As another measure, polymer waste is thermally decomposed by injecting it into the moving bed of coke dry fire extinguishing installation I (CDQ), and the pyrolyzed gas is combusted to increase the amount of steam generated. The method of conversion was published in JP-A-63-273
It is disclosed in Ell1 publication. However, with this method, the resulting CDQ circulating gas has a low calorie (E
~800kcal/Nm3).

Additionally, JP-A-48-28002 discloses a method of pulverizing old tires and carbonizing them together with coal, but this method converts about 32% of the fixed carbon contained in old tires into new It is used as a carbon raw material.

Problems to be Solved by the Invention The present invention decomposes polymer waste in the reducing atmosphere of a coke oven, without impairing the quality of the coke produced.
High calorie gas (4400-4800kcal/N layer 3
).

Here, the coke oven is an equipment for thermal decomposition and e-polymerization of coal, which has a higher molecular weight than plastics, and also has secondary treatment equipment, so it can be used as an alternative to the incineration treatment of plastics. For this reason, we investigated the incineration (pyrolysis) treatment of plastics in coke ovens and completed the present invention.

Means for Solving the Problems The present invention incorporates a maximum of 2 mm of polymer waste into charging coal.
A method for increasing COG recovery characterized by obtaining reduced decomposition gas by blending and mixing to 0%, charging the mixture into a coke oven and carbonizing it, and after carbonizing coal in a coke oven,
A method for increasing the amount of COG recovered, characterized in that polymeric waste with a layer Φ of 2 to 400 m is injected into the upper space of the carbonization chamber without stopping the generated gas suction system under the exclusion of the atmosphere to obtain reduced decomposition gas. It is.

Function In the present invention, polymeric waste is not particularly limited to, but includes high-calorie and harmful gases (CQ, N-based, etc.).
In order to avoid the generation of carbon dioxide, hydrocarbon-based polymers are preferred.9 For example, polyethylene.

Examples include polyolefins such as polypropylene, styrenes, acrylics, and the like.

Moreover, molded products are a typical form of polymer waste.

A coke oven is a reducing atmosphere, and the temperature inside the oven is 900 to 11
Because the temperature is as high as 00°C, the polymer waste is not combusted but decomposed into high-calorie reduced decomposition gases such as hydrogen, methane, ethane, propane, ethylene, and propylene.

The method of charging into a coke oven in the first invention is as follows:
Pulverize polymer waste, mix a predetermined amount of it with coal, charge the mixture into a coke oven in the same way as normal coking coal charge,
Carry out carbonization according to normal operation.

In this method, the particle size of the polymeric waste is 81
As shown in the figure, when coke with a large particle size is mixed with coal and carbonized, the pores formed in the coke produced after gasification become large. Therefore, the strength required for blast furnace coke, for example, DI: 83% or more, C9R: 54
In order to satisfy % or more, it is pulverized to 11 or less.

In addition, as for the blended amount of polymer waste, see Figures 2 and 3.
As shown in the figure, it is preferably 20% or less, preferably 10% or less based on the coke strength and porosity.The lower limit of the blending amount is not particularly limited, but as shown in the gas generation amount in Figure 2. As shown in the figure, if the amount is too small, the work will be complicated and the effect of the present invention will be small compared to the effect of increasing the recovery amount.Therefore, it is preferable to set the amount to 5% or more.

The method of charging into a coke oven in the second invention is as follows:
After carbonization of coal, polymeric waste is placed on top of the carbonized red hot coke in the carbonization chamber while blocking the atmosphere and without stopping the generated gas suction system.

As a means for charging the polymer waste while blocking the atmosphere, as shown in FIG. 5, a hopper 2 is provided in a moving vehicle, such as a charging vehicle (not shown), which runs above the coke oven I. At the bottom of this hopper 2 there are seal valves 4 in two stages, upper and lower.
．． A hopper 3 having 5 is provided. This hopper 3 is provided with an inert gas supply pipe 6 and a gas discharge pipe 7. 9 is a cylindrical chute.

According to this charging device, first, the cylindrical chute 9 is set in the charging port 10 of the coke oven l, and then, when the valve 4 is opened, the polymer waste particles 8 of a predetermined particle size in the hopper 2 are charged. It is introduced into the hopper 3. When the reception of a predetermined amount is completed, the valve 4 is closed, and when the valve 5 is opened while introducing an inert gas, such as nitrogen gas, from the inert gas supply pipe 6, the polymer waste particles 8 are transferred to a cylindrical chute. 9
The coke can be charged onto the carbonized red hot coke 11 in the carbonization chamber under exclusion of the atmosphere.

Although not shown, a hopper containing polymeric waste particles of a predetermined particle size may be directly pressurized with an inert gas and fed under pressure, and then charged under exclusion of the atmosphere.

As mentioned above, the particle size of the polymeric waste is limited by the diameter of the charging port 10 and the specifications of the charging device used, but it is generally applicable to a range of 2 to 200 layer carbon Φ.

In addition, the timing of addition is during coke maturation (approximately 2
It is preferable to charge the battery at a certain time.

That is, during this time, as shown in FIG. 4, the amount of gas generated in a normal coke oven is small, which is beneficial for flattening the amount of gas generated. Also, although a large amount of heat is radiated from the coke oven during the standing time, the radiated heat can be used as gas decomposition heat. The introduced polymeric waste is immediately gasified (about 60 degrees Celsius) at a temperature of about 1000 degrees Celsius in the carbonization chamber. Therefore, it is desirable that the introduction of the polymer waste into the carbonization chamber is completed at least 80 minutes before coke extrusion.Hereinafter, this will be explained in detail with reference to examples.

(1) 10 wt % of crushed polyethylene particles with an average particle size of 0.5 layer 1 were added to the charged coal and mixed. This mixture was charged into a coke oven using a conventional charging car and carbonized. Carbonization gas is originally 375Mm for 32ONm3/1-coal
3/1-coal was obtained. Moreover, the quality of the obtained coke was CSR: 81.5% and Di: 84.5%, which is comparable to coke for blast furnaces.

■ Using the charging device shown in Figure 5, 100 kg of polypropylene in a layer with a maximum diameter of 100 m is placed from the coal charging port closest to the riser pipe (not shown) of the carbonization chamber where coke carbonization has been completed, under exclusion of the atmosphere. I put it in. Carbonization gas is originally 23ONm3/
A carbonization gas of 29 ONm3/hr was obtained.

Effects of the Invention As described above, according to the present invention, polymer waste is charged into a coke oven, decomposed in a reducing atmosphere, and the amount of coke oven gas recovered can be increased without impairing the quality of the coke produced.
Since it can add I, its industrial effect is great.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the relationship between polymer waste particle size and coke strength, Figure 2 is an explanatory diagram showing the relationship between the amount of polymer waste particles added, coke strength, and gas generation amount. An explanatory diagram showing the relationship between the amount of polymer waste grains added and coke porosity, Figure 4 is an explanatory diagram showing the relationship between the elapsed time after carbonization and the amount of COG generated, and Figure 5 is an explanatory diagram showing the relationship between the amount of polymer waste particles added and the coke porosity. An explanatory diagram showing an example of a device for charging a coke oven under shut-off.

Claims (1)

[Claims] 1. A method of obtaining reduced decomposition gas by blending and mixing up to 20% of polymeric waste of 1 mm or less in charging coal, charging the mixture into a coke oven, and performing carbonization. Characteristic C
How to increase the amount of OG recovered. 2. After coal carbonization in a coke oven, polymeric waste with a diameter of 2 to 400 mm is charged into the upper space of the carbonization chamber under atmospheric exclusion without stopping the generated gas suction system to obtain reduced decomposition gas. How to increase COG recovery amount.