JPS5856556B2 - Heat treatment method for waste vinyl chloride resin, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heat treating waste vinyl chloride resin, etc.

Conventionally, wastes such as vinyl chloride resin are treated by heat treatment in a pyrolysis chamber, and the resulting pyrolysis gas is led to a pyrolysis gas condensation tower using steam to condense hydrogen chloride, and then to a separator to condense hydrogen chloride. There are some that are designed to recover hydrochloric acid.

However, in the above method, the pyrolysis product gas is guided to the pyrolysis gas condensation tower by steam, and hydrogen chloride is likely to condense in the low-temperature portion during transportation, resulting in corrosion of the ducts and the like.

In addition, there were other problems such as the inability to recover highly concentrated hydrochloric acid due to the large amount of condensed water.

This invention was made in consideration of the above-mentioned problems, and its purpose is to purge the inside of the pyrolysis chamber to create an inert atmosphere in advance with the combustion generated gas of hydrocarbon fuel, and to and/or the thermal decomposition gas generated during heat treatment of materials to be treated, such as thermoplastic synthetic resin waste, is transported to the outside of the thermal decomposition chamber to prevent explosions, corrosion of processing equipment, etc., and to achieve high concentration. The purpose of the present invention is to provide a heat treatment method for waste vinyl chloride resin, etc., which can recover hydrochloric acid, etc., and an apparatus therefor.

The present invention will be explained below with reference to an embodiment shown in the drawings.

The figure is a layout diagram showing a specific configuration for realizing the method according to the present invention, and the indirect heating type pyrolysis furnace 1 includes:
A pyrolysis chamber 2 and a heating furnace 2a for surrounding and heating the pyrolysis chamber 2
The pyrolysis chamber 2 has an inlet 3 for charging materials to be treated such as waste vinyl chloride resin, and a gas generated by combustion of hydrocarbon fuel (hereinafter referred to as combustion exhaust gas, gas generated by combustion of hydrocarbon fuel such as DX gas). is simply called combustion gas.

) A supply port 4 is provided.

This combustion gas supply port 4 is connected to a combustion gas generator 5.

The pyrolysis chamber 2 is connected via a duct 6 to a pyrolysis product gas condensing unit 9 equipped with a cooler 7 and a circulation pump 8, and the pyrolysis product gas generated during the heat treatment of the material to be treated is The combustion product gas is transported to the condensing group 9.

The condensing group 9 is connected to a pyrolysis coating bed gas cooling and washing tower 11 equipped with a circulation pump 10, and the pyrolysis product gas that has passed through the condensing group 9 is guided to this cooling and washing group 11.

The cooling washing base 11 is connected to a gas tank 13 via a cassette pump 12, and stores the pyrolysis product gas purified by the cooling washing base 11.

On the other hand, the gas tank 13 is connected to the heating furnace 2a of the pyrolysis furnace 1.
The stored gas is connected to a burner (not shown) provided in the heating furnace 2a, and is used as a fuel for the heating furnace 2a, and is also used as a hydrocarbon fuel for the combustion gas generator 5.

Further, when the exhaust port 1a of the heating furnace 2a is connected to the combustion product gas supply port 4, the combustion exhaust gas can be similarly supplied into the pyrolysis chamber 2 as a combustion product gas.

The thermal decomposition chamber 2 is provided with a residue discharge port 1b for discharging carbon and other residues generated during thermal decomposition of the material to be treated.

In the above configuration, when heat treating the material to be treated,
First, the inside of the heating chamber 2 is heated from the heating furnace 2a to approximately 400 to 800°C.
Next, the combustion gas is supplied from the combustion gas generator 5 to the pyrolysis chamber 2 to purge the active atmosphere to make the chamber an inert atmosphere. Charge.

Here, since the oxygen concentration in the pyrolysis chamber 2 is about 1.5% or less, there is no possibility of inducing an explosion or the like during the pyrolysis.

The material to be treated is thermally decomposed in the thermal decomposition chamber 2, and the thermal decomposition gas containing hydrogen chloride, hydrogen, methane, etc. generated at that time is transferred to the combustion gas generator 5 for transportation. The combustion product gas supplied from the duct 6 is guided to the condensing group 9 through the duct 6.

In the condensing group 9, hydrogen chloride in the pyrolysis product gas and about 6
Organic substances with a boiling point of 0°C or higher are condensed and separated.

Here, the main component of the combustion generated gas for conveyance is non-condensable and has no or little latent heat of condensation unlike water vapor, so the capacity of the cooler 7 may be small.

The separated hydrogen chloride, etc. is led from the condensing group 9 to a separator (not shown) and separated into hydrochloric acid and oil by gravity separation, and the hydrochloric acid is further led to an activated carbon adsorption column (not shown) and mixed into the hydrochloric acid. Organic substances as off-flavor components are adsorbed and removed,
It is possible to recover hydrochloric acid with a concentration of about 30-35% comparable to that of synthetic hydrochloric acid.

On the other hand, the pyrolysis product gas treated in the condensing group 9 is led to the cooling and washing group 11, where it is washed with alkali to remove impurities, and then stored in the tank 13 by the pump 12, and then transferred to the pyrolysis furnace 1. It is provided as a fuel or a hydrocarbon fuel for the combustion gas generator 5.

In the above method, combustion gas is used to transport the pyrolysis gas, but if the amount of pyrolysis gas is large or to obtain gas with a high calorific value, it may not be necessary to use it all the time. Good too.

In the above apparatus, if the exhaust port 1a of the heating furnace 2a is connected to the combustion product gas supply port 4 of the pyrolysis chamber 2, the combustion product gas generator 5 is not required, reducing equipment costs and maintenance costs. be able to.

In the above embodiments, the case where vinyl chloride resin is used as the material to be treated has been described, but it goes without saying that the technical idea of the present invention can also be applied to thermoplastic resin waste.

As described above, according to the method according to the present invention, the pyrolysis chamber is purged in advance with the gas produced by combustion of hydrocarbon fuel to create an inert atmosphere, so that vinyl chloride resin and/or thermoplastic When thermally decomposing the resin waste material to be treated, it is possible to cause an explosion, etc.
Reactions occur between CO2 and H2O in the combustion gas and the thermal decomposition components, and a sufficiently lightened thermal decomposition gas can be obtained.

In addition, since the lightened combustion gas is non-condensable, it can reduce condensation in low-temperature parts of the processing equipment, prevent corrosion, and has no latent heat of condensation unlike water vapor. , the capacity of the cooler in the pyrolysis product gas condensation group can be made small.

In addition, since combustion gas is already used for conveying the pyrolysis gas, especially for vinyl chloride resin, the concentration of recovered hydrochloric acid is about 30 to 30%, which is the same concentration as synthetic hydrochloric acid.
It can be 5%.

Furthermore, if the combustion exhaust gas of the heating furnace is used for purging the pyrolysis chamber and as the pyrolysis product gas, a combustion product gas generator, etc. is not required, and equipment costs and maintenance costs can be reduced. .

[Brief explanation of drawings]

The figure is a layout diagram of a specific device for implementing the method of the present invention. 1... Indirect heating furnace, 2... Pyrolysis chamber, 2a... Heating furnace, 3... Processing material charging port, 4... ...Combustion generated gas supply port, 5...
... Combustion product gas generator, 9... Condensation group, 11
...Cooling cleaning base, 13...Gas tank.

Claims (1)

[Scope of Claims] 1. In a heat treatment method in which a material to be treated of vinyl chloride resin and/or thermoplastic synthetic resin waste is pyrolyzed in a low-oxygen atmosphere in an indirect heating type pyrolysis furnace, during the heat treatment, carbonization is first performed. After purging the high oxygen atmosphere in the pyrolysis chamber of the pyrolysis furnace with the combustion generated gas of the hydrogen-based fuel, the material to be treated is supplied to the pyrolysis chamber for heat treatment, and the heat generated in the pyrolysis chamber is A method for heat treatment of waste vinyl chloride resin, etc., characterized in that the decomposition product gas is transported to a condensation group by the combustion product gas. 2. The method for heat treatment of waste vinyl chloride resin, etc. according to claim 1, characterized in that the combustion exhaust gas from the pyrolysis furnace is used as the combustion generated gas supply source.