Method and Apparatus for Microwave Depolymerization of Hydrocarbon Feedstocks

Abstract

A method and apparatus is provided for the continuous microwave depolymerization of high molecular weight organic feedstock material, such as waste plastics and includes intermittent or continuous feeding of the processing material on the surface or into the bulk of the sensitized hot bed located under microwave irradiation. As a result of the interaction of electromagnetic field with processed materials, sensitizer is heated by microwave energy and feedstock material undergoes the depolymerization reactions. The reaction zone can be localized on the surface of the hot bed or distributed in the bulk of the reaction mass depending on the agitation conditions of the reaction mass, such as stirring, or other agitation means, for example by re-circulated gas. Products of the reactions are vaporized and transported to the collection system, which may include a combination of a scrubber, a condenser and a settler.

What is claimed is: 
     
         1 . Apparatus for the continuous processing of high molecular weight organic materials, comprising:
 a reaction vessel constructed and arranged to receive the high molecular weight organic materials, the reaction vessel having a top portion and a bottom portion and enclosing a volume;   an opening in the reaction vessel to receive the high molecular weight organic materials;   a source of microwave energy which is constructed and arranged to impinge upon to heat the materials within the reaction vessel and cause microwave depolymerization of the materials;   the depolymerization by microwave energy heating the materials to form liquid portions and vapor portions;   the liquid portion migrating to the bottom portion of the reaction vessel; and,   a collection apparatus constructed and arranged to remove one or more of the liquid portion and the vapor portion of the materials from the reaction vessel.   
     
     
         2 . The apparatus of  claim 1 , wherein the opening in the reaction vessel further comprises an access opening in the top portion of the reaction vessel for at least one of continuous and intermittent feeding of the organic materials into the reaction vessel. 
     
     
         3 . The apparatus of  claim 1 , wherein the source of microwave energy is constructed and arranged to introduce microwave energy through a waveguide into the reaction vessel from one or more entry ports located in the upper portion of the reaction vessel. 
     
     
         4 . The apparatus of  claim 1 , wherein the collection apparatus comprises at least two access ports into the reaction vessel, one of the at least two access ports being located in the liquid portion of the reaction vessel and another of the at least two access ports being located in the vapor portion of the reaction vessel, the at least two access ports constructed and arranged to remove the liquid portion and the vapor portion from the reaction vessel. 
     
     
         5 . The apparatus of  claim 4 , wherein a scrubber is operatively connected to one of the at least two access ports, and wherein the vapor portion removed from the reaction vessel is condensed by the scrubber. 
     
     
         6 . The apparatus of  claim 1  wherein the liquid portion and the vapor portion are removed one of continuously and intermittently. 
     
     
         7 . The apparatus of  claim 5 , further comprising a separator device downstream of the scrubber, the separator device causing the separation of at least the vapor portions and the liquid portions of materials exiting the scrubber. 
     
     
         8 . The apparatus of  claim 1 , wherein the microwave energy operates in the range from about 300 MHz to about 3 GHz. 
     
     
         9 . The apparatus of  claim 1  wherein the top portion comprises a microwave cavity, the microwave cavity being partitioned into at least two zones comprising an upper zone and a lower zone, the lower zone being at a temperature higher than the temperature of the upper zone. 
     
     
         10 . The apparatus of  claim 8 , wherein the microwave energy operates at about 900 MHz. 
     
     
         11 . The apparatus of  claim 1 , further comprising at least one of a mechanical mixer and a gaseous material input positioned within the reaction vessel, the at least one of a mechanical mixer and a gaseous material input mixing the liquid portion of the materials. 
     
     
         12 . The apparatus of  claim 11 , wherein the mechanical mixer is located in the bottom portion of the reaction vessel, the bottom portion of the vessel comprising a flat surface. 
     
     
         13 . The apparatus of  claim 11 , wherein the mechanical mixer is located in the bottom portion of the reaction vessel, the bottom portion of the vessel being in the form of an inverted truncated cone. 
     
     
         14 . The apparatus of  claim 1 , further comprising a non-microwave source of heating at least partially contacting the bottom portion of the reaction vessel. 
     
     
         15 . The apparatus of  claim 3 , further comprising a barrier which is transparent to microwave energy located in the vicinity of the waveguide port to isolate the microwave energy source from the vapor and liquid portions in the reaction vessel. 
     
     
         16 . The apparatus of  claim 3 , further comprising a port in the vicinity of the waveguide to introduce a gaseous material into the waveguide to isolate the microwave energy source from the vapor and liquid portions in the reaction vessel. 
     
     
         17 . The apparatus of  claim 1 , further comprising at least one port in the reaction vessel to introduce high molecular weight materials in liquid form into the bottom portion of the reaction vessel. 
     
     
         18 . The apparatus of  claim 1 , further comprising at least one port in the reaction vessel to remove high molecular weight materials in liquid form from the bottom portion of the reaction vessel. 
     
     
         19 . The apparatus of  claim 1 , wherein the high molecular weight organic materials comprises one or more of: waste plastics, waste oils, petroleum residues, tires, oil sands, oil shale and cellulose materials. 
     
     
         20 . The apparatus of  claim 1 , wherein the temperature in the bottom portion of the reaction vessel is in the range of about 250 degrees C. to about 425 degrees C. 
     
     
         21 . The apparatus of  claim 1 , wherein the temperature in the top portion of the reaction vessel is in the range of about 50 degrees C. to about 200 degrees C. 
     
     
         22 . The apparatus of  claim 1 , wherein the pressure in the reaction vessel is in the range of about minus 10 psig to about plus 15 psig. 
     
     
         23 . The apparatus of  claim 1 , further comprising a sensitizer in the reaction vessel, the sensitizer being subjected to be impinged upon by the source of microwave energy. 
     
     
         24 . The apparatus of  claim 1 , wherein the microwave energy is of sufficient power and duration to cause microwave depolymerization of the high molecular weight materials. 
     
     
         25 . The apparatus of  claim 23 , wherein the impingement of microwave energy on the materials and the sensitizer causes further sensitizer to be formed. 
     
     
         26 . The apparatus of  claim 23 , wherein the sensitizer formed is in the form of carbon particles. 
     
     
         27 . The apparatus of  claim 25 , wherein the sensitizer formed is in the form of carbon dendrites. 
     
     
         28 . The apparatus of  claim 11 , further comprising at least one port for the introduction of the gaseous material into the bottom portion of the reaction vessel for mixing the liquid portion of the materials in the bottom portion of the reaction vessel. 
     
     
         29 . The apparatus of  claim 1 , further comprising at least one source of heat to heat the top portion of the reaction vessel. 
     
     
         30 . The apparatus of  claim 7  wherein the collection apparatus includes crude wax tank which receives the output from the reaction vessel access ports. 
     
     
         31 . The apparatus of  claim 30 , further comprising one or more refining units downstream of the crude wax tank. 
     
     
         32 . The apparatus of  claim 31 , wherein the one or more refining units comprises one or more of units for: distillation, hydroprocessing, isomerization and fractionation. 
     
     
         33 . A method for the continuous processing of high molecular weight materials comprising the steps of:
 introducing the materials into a reaction vessel through an opening in the vessel;   utilizing a microwave source, impinging microwave energy on the materials, the microwave energy causing heating and microwave depolymerization of the materials in the reaction vessel;   the depolymerization step causing the formation of a vapor portion and a liquid portion form the materials;   the liquid portion migrating to a lower portion of the reaction vessel; and,   removing one or more of the liquid portion and the vapor portion from the reaction vessel.   
     
     
         34 . The method of  claim 33 , further comprising the step of introducing a sensitizer into the reaction vessel to assist in depolymerizing the materials. 
     
     
         35 . The method of  claim 33 , further comprising the step of directing the removed vapor portion to a scrubber to condense the vapor portion. 
     
     
         36 . The method of  claim 35 , further comprising the step of directing the material from the scrubber to a separator device. 
     
     
         37 . The method of  claim 33 , wherein the reaction vessel is a sealed vessel and pressurizing the vessel with an internal pressure in the range of about minus 10 psig to about plus 15 psig. 
     
     
         38 . The method of  claim 33 , further comprising the step of maintaining the temperature of the vessel in the range of 250 degrees C. to about 425 degrees C. 
     
     
         39 . The method of  claim 34 , wherein the microwave depolymerization of the materials produces additional sensitizer without the need for further introducing further sensitizer into the vessel from outside the vessel. 
     
     
         40 . The method of  claim 33 , wherein the microwave source is operated in the range of about 300 MHz to about 3 GHz. 
     
     
         41 . The method of  claim 40 , wherein the microwave source is operated at about 900 MHz. 
     
     
         42 . The method of  claim 33 , wherein the temperature of the liquid portion is in the range of about 350 degrees C. to about 425 degrees C. 
     
     
         43 . The method of  claim 33 , wherein the high molecular weight material comprises one or more of: waste plastics, waste oils, petroleum residues, tires, oil sands, oil shale and cellulose materials. 
     
     
         44 . The method of  claim 33 , further comprising the step of providing a further source of heating to the reaction vessel to heat the materials in the vessel. 
     
     
         45 . The method of  claim 33 , further comprising the step of mixing the liquid portion of the materials utilizing at least one of a mechanical stirrer and a gaseous fluid input. 
     
     
         46 . The method of  claim 33 , wherein the one or more of the liquid portion and the vapor portion removed from the reaction vessel are collected in a crude wax holding tank. 
     
     
         47 . The method of  claim 46  further comprising the step of refining the crude wax collected in the crude wax holding tank. 
     
     
         48 . The method of  claim 47 , wherein the steps of refining the molten heavy wax comprises one or more of the steps of: distillation, hydroprocessing, isomerization and fractionation. 
     
     
         49 . The method of  claim 33 , wherein the step of removing one or more of the liquid portion and the vapor portion is one of intermittent and continuous.