Apparatus for and method of treating waste containing plastic material

Abstract

Apparatus and method for treating waste products containing plastic materials by pyrolysis is disclosed. The method includes pyrolytically decomposing the waste products containing plastic materials by thermolysis to obtain useful liquid and gaseous organic raw materials. The method is carried out continuously.

1 . Apparatus for the treatment of waste containing plastic material, comprising:
 a container which is closed except for inlets and outlets and which in operation is to be filled with a liquid metal bath up to a liquid metal level and has a gas space above the liquid metal level;   a waste feed opening for waste to be treated;   a residual material outlet opening for solid waste residues;   a waste conveyor device which extends substantially horizontally between the waste feed opening and the residual material outlet opening and which is adapted to convey waste at least in portion-wise manner beneath the liquid metal level from the waste feed opening to the residual material outlet opening and in so doing to periodically immerse waste which floats upwardly deeper into the liquid metal bath;   a gas feed line for an inert gas, which opens into the gas space;   a gas outlet connected to the gas feed line by way of conduits to afford a gas circuit;   a condenser arranged in the gas circuit for condensable gas constituents;   a feed line opening into the condenser for a carrier liquid; and   a liquid discharge line arranged in a base point of the condenser.   
   
   
       2 . Apparatus according to  claim 1 , wherein the conveyor device is enclosed by its own casing within the container, a first portion of the conveyor device extending close to the waste feed opening in part above the liquid metal level, further portions of the conveyor device extending into the proximity of the residual material outlet opening beneath the liquid metal level. 
   
   
       3 . Apparatus according to  claim 1  or  2 , wherein the conveyor device comprises a plurality of conveyor elements which are arranged around an at least approximately horizontally extending axis of rotation of the conveyor device. 
   
   
       4 . Apparatus according to  claim 3 , wherein the conveyor elements of the conveyor device comprise rotationally moving, blade-like entrainment members which extend at least approximately to the casing of the conveyor device. 
   
   
       5 . Apparatus according to  claim 4 , wherein the entrainment members of the conveyor device extend in a plane extending at least approximately parallel to the axis of rotation and transversely with respect to the direction of rotation. 
   
   
       6 . Apparatus according to  claim 1 , wherein the conveyor elements comprise chutes which adjoin the entrainment members near the axis of rotation and comprise a chute bottom extending inclinedly with respect to the axis of rotation. 
   
   
       7 . Apparatus according to  claim 3 , wherein the conveyor device further comprises entrainment plates which in comparison with the entrainment members are of a shorter extent in relation to the radial direction, are at a greater spacing relative to the axis of rotation, and also extend to close to the casing of the conveyor device. 
   
   
       8 . Apparatus according to  claim 2 , wherein the casing of the conveyor device further comprises an opening at the end of the conveyor device in the proximity of the residual material outlet on its top side beneath the liquid material level, which opening opens into a discharge chamber whose flat bottom extends at the level of the surface of the liquid metal. 
   
   
       9 . Apparatus according to  claim 8 , wherein the discharge chamber further comprises a rotating bladed wheel, the wheel comprising blades which extend to the bottom of the discharge chamber and to the edge of the discharge chamber. 
   
   
       10 . A method of treating plastic material-containing waste, comprising:
 introducing waste into a container containing a liquid metal bath and a gas atmosphere thereabove;   immersing the waste into the liquid metal bath;   conveying the waste within the liquid metal bath, thereby producing thermolysis gas and solid residue materials;   flushing the gas atmosphere with an inert gas;   separating the thermolysis gas from the inert gas in a condenser;   dissolving condensed pyrolysis gas in a carrier liquid;   draining the carrier liquid and liquid condensed thermolysis products from the condenser, and   removing remaining solid materials from the liquid metal bath.   
   
   
       11 . A method according to  claim 10 , wherein the method is carried out continuously. 
   
   
       12 . A method according to  claim 10 , wherein the carrier liquid comprises an oil or tuluol. 
   
   
       13 . A method according to  claim 10 , wherein the liquid metal bath further comprises lime for binding chlorine. 
   
   
       14 . A method according to  claim 10 , carried out at temperatures of between 450° C. and 500° C. 
   
   
       15 . A method according to  claim 10 , wherein the liquid metal bath comprises tin. 
   
   
       16 . A method according to  claim 10 , wherein the residence time of waste to be treated in the liquid metal bath is about two minutes. 
   
   
       17 . A method according to  claim 10 , wherein the waste to be treated is conveyed in the liquid metal bath in an at least approximately horizontal direction.