Method and apparatus for producing oil from waste plastic

Abstract

The present invention provides a method for producing oil from waste plastic, in which, when waste plastic is introduced into a thermal decomposition chamber and mixed with a high-temperature solvent to carry out thermal decomposition, the solvent is heated more uniformly within a shorter time and blended oil generated in the thermal decomposition chamber can be cooled more uniformly within a shorter time. The present invention also provides an apparatus for producing oil from waste plastic, which utilize such a novel method. The method and apparatus for producing oil from waste plastic are those each configured such that a first circulation device having a circulation chamber 12 and a heating device 13 , which can be functioned to heat and store a solvent, and a second circulation device capable of supplying purified lower-temperature blended oil are connected to each of the thermal decomposition chambers 10 and 30 , where a high-temperature solvent is continuously flowed until it is completely decomposed, while it can be cooled when the decomposed oil generated is discharged.

1 . A method of manufacturing oil by thermal decomposition of waste plastic with a high temperature solvent heated sufficiently to separate refined oil from the waste plastic, to obtain refined oil from the waste plastic, wherein 
 depositing waste plastic into a thermal decomposition chamber having an output port for decomposed oil provided with a closable gate for separating intact plastic and solid impurities from the decomposed oil;    heating said solvent in a first circulation device capable of heating and storing the solvent;    flowing the high-temperature solvent continuously from the first circulation device to the thermal decomposition chamber until the waste plastic is completely decomposed in the thermal decomposition chamber; and    supplying purified lower-temperature blended oil from a second circulation device, the lower-temperature blended oil being supplied to the thermal decomposition chamber to cool down the decomposed oil.    
   
   
       2 . The method for producing oil from waste plastic according to  claim 1 , wherein the first circulation device comprises a heating device, a circulation chamber for storing the solvent, and a circulation channel for flowing heated solvent to the thermal decomposition chamber, and wherein 
 the second circulation chamber is disconnectable from both the circulation chamber and the heating device.    
   
   
       3 . The method for producing oil from waste plastic according to  claim 2 , wherein 
 both of the thermal decomposition chambers are employed to dissolve the waste plastic deposited into each thermal decomposition chamber in the solvent heated at a predetermined temperature to produce decomposed oil;    while cooling down one of the thermal decomposition chambers, the other of the thermal decomposition chambers allows the solvent to be heated by the heating device and to be circulated through the circulation chamber to carry out thermal decomposition of additionally-introduced waste plastic; and    all of decomposed oil and solid impurity are drawn from a separator while being cooled down to a predetermined temperature by the lower-temperature blended oil.    
   
   
       4 . An oil-producing apparatus, which thermally decomposes waste plastic in a high-temperature solvent to obtain refined oil from the waste plastic, comprising: 
 a thermal decomposition chamber that receives the high-temperature solvent and receives the introduction of waste plastic, where the thermal decomposition chamber is connected to a first circulation device having a function of moving a solvent in a thermal decomposition chamber and a second circulation device capable of supplying lower-temperature blended oil from a product-receiving chamber storing the purified blended oil, wherein    a circulation chamber capable of storing a solvent having a capacity about 10 times higher than that of the thermal decomposition chamber, a first heating device for heating the solvent up to a predetermined temperature, and a pump are arranged as common instruments for each of the first circulation device and the second circulation device, and a separating device for separating the decomposed oil from solid impurities is connected to an output port for decomposed oil of the thermal decomposition chamber through a closable gate.    
   
   
       5 . The apparatus for producing oil from waste plastic, according to  claim 4 , wherein 
 two thermal decomposition chambers are placed and connected to the first circulation device and the second circulation device, respectively, in a switchable manner.    
   
   
       6 . The apparatus for producing oil from waste plastic, according to  claim 5 , further comprising: 
 a second heating device for heating the decomposed oil, provided as a device for purifying the decomposed oil out of the separating device; and    an evaporation chamber having a device for enlarging the surface area of the decomposed oil heated by the second heating device.    
   
   
       7 . The apparatus for producing oil from waste plastic, according to  claim 6 , wherein 
 the first heating device and the second heating device are provided as devices for controlling heating temperatures, having: a heat-generating member arranged in the heating chamber, provided with a screw-type heat-generating plate on a spindle, and made of an electroconductive steel product; and a control device arranged on the outside of the heating chamber and provided for supplying a predetermined electric power to the heat-generating member on the basis of information about temperature from a temperature sensor arranged on the outlet side of a heating fluid in the heating chamber.    
   
   
       8 . The apparatus for producing oil from waste plastic, according to  claim 7 , wherein 
 a plurality of the heat-generating members is arranged in parallel to the direction of flow in the heating chamber and placed at positions that divide the inside of the heating chamber almost evenly.