JP2004269811A - Method for recycling waste product mainly comprising plastic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recycling waste products mainly comprising plastic resin that can recover thermally cracked gas and oil of high addition value in high recovery percentage by using inexpensive installation. <P>SOLUTION: In the method for recycling waste products mainly comprising plastic resin, the waste products mainly comprising plastic resin is subjected to the thermal cracking to recover cracked gas and/or oil and they are recycled. In this case, steam is fed into the thermally cracked reaction mixture thereby controlling the cracking process and/or the recovery percentage of the gas and/or oil. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１３】
【発明の効果】
本発明によれば、熱分解中に水蒸気を供給し、回収される前記ガスおよび／または油の組成および／または回収率を制御することによって、より安価な設備で高付加価値のガスや油を高い回収率で再資源化することができる、樹脂を主体とする廃棄物の再資源化方法を提供することができるなど、産業上有用な著しい効果を奏する。
【図面の簡単な説明】
【図１】本発明における樹脂を主体とする廃棄物の再資源化方法の実施形態を例示するプロセスフロー図である。
【図２】本発明に用いる水蒸気が油の品質に及ぼす影響を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for recycling waste, which is a method of recovering gas and / or oil by pyrolyzing waste mainly composed of resin, and improving the material recycling ratio and improving the effective use of resources. The present invention relates to a processing method for controlling the composition and recovery of gas and oil obtained after decomposition.
[0002]
[Prior art]
JP-A-49-111986, JP-A-51-135983, and the like are examples of a single system for dry-distilling waste mainly composed of resin such as waste tires and waste plastics to obtain a dry-distilled gas, recovered oil and carbide. , There are many.
For example, Japanese Patent Application Laid-Open No. 2000-296378 discloses that in the gasification of waste, a decrease in the calorific value of the highly gasified gas is prevented without forming oil, and in the incineration of waste, the waste gas or incinerated ash There is disclosed a waste treatment method which enables the amount of harmful substances to be reduced. The measures are as follows: gasification of organic waste, gasification accelerator in gasification furnace, combustion incineration of organic waste, combustion promoter in combustion field, hazardous substance decomposer in incineration ash, exhaust gas In this method, high-temperature steam of 600 ° C. or more is introduced as a harmful substance decomposing agent.
However, there is a problem that it is costly to industrially obtain superheated steam of 600 ° C. or higher, and that the calorific value of the recovered gas also decreases.
[0003]
On the other hand, Japanese Patent Application Laid-Open No. 2002-336673 discloses a method of decomposing organic waste by using superheated steam at 550 ° C. or lower as a high-speed decomposition method.
However, this conventional technique is a method of oxidatively decomposing organic waste by all or any combination of an oxidation reaction with oxygen in air and drying with superheated steam, a hydrolysis reaction, and a pyrolysis reaction. There is no description on the composition of the gas or oil to be recovered by pyrolysis, which is the subject of the present invention, and on the control of the recovery rate because it is a heat source.
Japanese Patent Application Laid-Open No. 2002-322481 discloses a method of carbonizing organic waste under an atmosphere of superheated steam.
However, in this conventional technique, the air in the furnace is replaced with superheated steam, thereby making the oxygen concentration in the furnace extremely low to form a good carbonized atmosphere of organic substances. No mention is made of the composition of the gas or oil to be recovered by thermal decomposition or the control of the recovery.
[0004]
[Patent Document 1] JP-A-49-111986 [Patent Document 2] JP-A-51-135983 [Patent Document 3] JP-A-2000-296378 [Patent Document 4] JP-A-2002-333673 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-322481
[Problems to be solved by the invention]
As mentioned above, various proposals have been made regarding the recycling of waste mainly composed of resin for the construction of a recycling-based society, but all of them are based on the premise that the processing cost is expensive. There were also many unresolved issues such as the need to maintain high quality and recovery rates of recovered gas and oil.
Therefore, the present invention relates to a resin-based waste that can be used to recycle high value-added gas and oil at a high recovery rate with less expensive equipment in the recycling of resin-based waste. An object of the present invention is to provide a method for recycling resources.
[0006]
[Means for Solving the Problems]
The present invention solves the above-mentioned problems of the prior art, and supplies steam during pyrolysis to control the composition and / or recovery rate of the recovered gas and / or oil, thereby reducing the cost. The present invention provides a method for recycling resin-based waste, which can recycle high value-added gas and oil with a high recovery rate using simple equipment. The following contents are described as described in the range.
(1) In a waste recycling method for recovering gas and / or oil by thermally decomposing waste mainly composed of resin, steam is supplied during the pyrolysis to recover the gas and / or oil recovered. A method of recycling resin-based waste, characterized by controlling the composition and / or recovery of oil.
(2) The method for recycling waste as described in (1), wherein the steam supplied during the pyrolysis is superheated steam of less than 600 ° C.
(3) The steam according to (1) or (2), wherein steam supplied during the thermal decomposition uses steam generated by heat exchange between high-temperature gas generated by the thermal decomposition and water. How to recycle waste.
(4) The recycling of waste according to (1) to (3), wherein the resin-based waste contains one or more of waste tire, waste plastic, and shredder dust. Method.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 1 is a process flow diagram illustrating an embodiment of a method for recycling waste mainly composed of resin according to the present invention.
In the present invention, resin-containing waste mainly composed of resin such as waste tires, waste plastics, and shredder dust is supplied with steam during the thermal decomposition when the gas and / or oil is recovered by pyrolysis. By supplying steam, the apparent gas volume in the furnace is increased, and the residence time of the pyrolyzed gas in the furnace is shortened, so that the reaction time changes, so the recovery rate and composition of the gas and oil are controlled. Gas and oil with higher added value can be provided.
In particular, by exchanging heat between gas and water recovered by pyrolysis, water vapor is produced by the hydrogasification reaction and supplied during pyrolysis, making it possible to use waste heat from pyrolysis at low cost. Steam can be supplied.
[0008]
Further, by increasing the temperature of the steam to form superheated steam of less than 600 ° C. and supplying it during pyrolysis, the gas recovery rate can be significantly increased.
The reason why the temperature is lower than 600 ° C. is that if the temperature is higher than this, the production cost of superheated steam increases. The temperature of the heated steam is preferably 400 ° C. or higher. If the temperature is lower than 400 ° C., the temperature of the atmosphere in the furnace decreases, and the thermal decomposition reaction does not easily proceed.
In addition, in the present invention, the method of thermal decomposition is not limited, but in order to recover gas and oil, an indirect heating method such as an externally heated rotary kiln is preferable. Energy cost can be reduced by using it as a heat source for the thermal decomposition treatment.
[0009]
FIG. 2 is a diagram showing the effect of steam used in the present invention on oil quality.
In FIG. 2, the horizontal axis indicates the residence time index (min) in the pyrolysis gas furnace in consideration of the apparent increase in gas volume when steam is supplied, and the vertical axis indicates the weight loss rate at 100 ° C. of the thermobalance ( %), Which indicates an oil quality index. The lower this value is, the smaller the ratio of light components such as light oil is, and the higher the yield of heavy oil is.
In FIG. 2, a circle indicates a case where steam is not supplied at a pyrolysis temperature of 600 ° C. and a waste processing speed of 170 kg / hr, and a triangle indicates a case where steam is not supplied at a pyrolysis temperature of 650 ° C. and a waste processing speed of 240 kg / hr. The mark ● indicates the case where steam is supplied at a thermal decomposition temperature of 600 ° C. and a waste treatment rate of 170 kg / hr.
As shown by the dotted line on the right side of FIG. 2, by supplying steam, the apparent gas volume increases, so that the residence time index (min) in the pyrolysis gas furnace decreases, and the oil quality index decreases accordingly. Since the ratio of light components such as light oil in oil is low and the ratio of heavy oil is high, it is possible to supply oil that is difficult to catch fire and that can simplify equipment safety measures.
[0010]
Similarly, in FIG. 2, the symbol □ indicates that the steam is not supplied at the thermal decomposition temperature of 700 ° C. and the waste processing speed of 420 kg / hr, and the symbol Δ indicates that the steam is supplied at the thermal decomposition temperature of 700 ° C. and the waste processing speed of 420 kg / hr. In this case, the * mark indicates a case where excessive pyrolysis was performed at a thermal decomposition temperature of 720 ° C. and a waste disposal rate of 170 kg / hr.
As shown by the dotted line on the left side of FIG. 2, by supplying steam, the apparent gas volume increases, the residence time index (min) in the pyrolysis gas furnace decreases, and the oil quality index decreases accordingly. Since the ratio of light components such as light oil in oil is low and the ratio of heavy oil is high, it is possible to supply oil that is difficult to catch fire and that can simplify equipment safety measures.
In addition, conventionally, in order to increase the ratio of heavy oil, the recovered oil may be subjected to distillation again in some cases. However, according to the present invention, the ratio of heavy oil can be increased at the time of collection. The need for a redistillation process is eliminated.
[0011]
【Example】
Using an externally heated rotary kiln having an inner diameter of 800 mm and a length of 6000 mm, a thermal decomposition experiment was performed on cut tires having an average particle size of 30 mm under the conditions shown in Table 1.
<Example-1>
This is an example of the present invention in which steam was supplied at a rate of 80 kg / hr during pyrolysis. By supplying steam, the apparent gas volume was large, so that the residence time of the pyrolysis gas in the furnace was short, and the oil light fraction was 20%. However, since the supplied steam temperature was relatively low at 150 ° C., the gas recovery rate was 18%.
<Example-2>
This is an example of the present invention in which steam was supplied at a rate of 80 kg / hr during the pyrolysis. The apparent gas volume was large due to the supply of the steam, so the residence time of the pyrolysis gas in the furnace was short, and the oil light fraction was 15%. In addition, the supply of superheated steam at 400 ° C. during the pyrolysis increased the gas recovery rate to 46%.
<Example-3>
This is an example of the present invention in which steam was supplied at a rate of 80 kg / hr during the pyrolysis. By supplying the steam, the apparent gas volume was large, so that the residence time of the pyrolysis gas in the furnace was short, and the light oil content became 10%. Since 580 ° C. superheated steam was supplied during the thermal decomposition, the gas recovery rate was further increased to 51%.
[0012]
<Comparative Example-1>
This is a comparative example in which water vapor of 80 kg / hr and oxygen of 24 Nm3 / hr were supplied during pyrolysis. The gas recovery rate was 42% by supplying oxygen. In addition to falling to nearly half of the cases, the oil light fraction increased to 80%.
<Comparative Example-2>
This is a comparative example in which neither steam nor oxygen was supplied at the time of pyrolysis. The gas recovery rate was as low as 18%, and the ratio of light oil components was relatively high as 28%.
<Experimental results>
As a result of this experiment, by supplying steam or superheated steam during pyrolysis, the gas recovery rate can be increased and the oil light fraction can be reduced. It has been confirmed that the ratio can be controlled and high value-added gas and oil can be provided with inexpensive equipment.
[Table 1]

[0013]
【The invention's effect】
According to the present invention, by supplying steam during pyrolysis and controlling the composition and / or recovery rate of the gas and / or oil to be recovered, high-value-added gas and oil can be produced with less expensive equipment. It has remarkable industrially useful effects, such as being able to recycle at a high recovery rate and providing a method of recycling waste mainly composed of resin.
[Brief description of the drawings]
FIG. 1 is a process flow diagram illustrating an embodiment of a resin-based waste recycling method according to the present invention.
FIG. 2 is a diagram showing the effect of steam used in the present invention on oil quality.

Claims (4)

In a waste recycling method for recovering gas and / or oil by thermally decomposing waste mainly composed of resin, the composition of the recovered gas and / or oil is supplied by supplying steam during the pyrolysis. And / or controlling the recovery rate. A method for recycling waste mainly composed of resin. The method according to claim 1, wherein steam supplied during the pyrolysis is superheated steam having a temperature of less than 600C. The wastewater according to claim 1 or 2, wherein steam supplied during the pyrolysis uses steam generated by exchanging heat between high-temperature gas and water generated by the pyrolysis. Recycling method. 4. The method according to claim 1, wherein the resin-based waste contains one or more of waste tire, waste plastic, and shredder dust. 5.

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