WO2011142829A2

WO2011142829A2 - Apparatus and method for the decomposition of organic matter

Info

Publication number: WO2011142829A2
Application number: PCT/US2011/000846
Authority: WO
Inventors: Richard Swetnam
Original assignee: W2OIL Inc
Current assignee: W2OIL Inc
Priority date: 2010-05-13
Filing date: 2011-05-12
Publication date: 2011-11-17
Anticipated expiration: 2012-11-13
Also published as: WO2011142829A3

Abstract

A system for the decomposing organic matter which may be used as a stand-alone unit or in conjunction with other prior art organic decomposition systems. The system includes a thermally insulated enclosure, a reaction vessel within the insulated enclosure, an entry port for the introduction of organic matter into the reaction vessel, a substantially round metal surface within the reaction vessel and onto which organic matter is introduced, burners located beneath the reaction vessel to heat the round metal surface to between 500 and 1,400 degrees F., at least one paddle inside the reaction vessel rotating on a central axis about the metal surface to agitate the organic matter as it rests on the metal surface, an exit port for the discharge of solid materials from the reaction vessel and thermally insulated enclosure, and an exit port for the exhaustion of gases generated within the reaction vessel that can then be condensed into liquids or retained in gaseous forms. The benefits of the present invention include, among other things, simple mechanics, high surface-to-volume ratio to allow more organic matter to be exposed to the heated surface, self-cleaning mechanisms, ease in adaptability with other systems, and high heat capacity.

Description

DECOMPOSITION OF ORGANIC MATTER

The present invention relates to an apparatus and process, and the product of that process, for the thermal decomposition of organic matter using pyrolysis and/or ablative processes. Prior art systems are known that use heat to decompose organic matter in an enclosure (referred to hereafter generally as "pyrolysis" or "pyrolytic processes"). There are also prior art systems under which organic matter is introduced onto a heated metal plate, thereby causing decomposition of the organic matter through the transfer of heat from the hot plate to the organic matter (referred to hereafter generally as "ablative processes"). The prior art also includes systems that use a combination of pyrolysis and ablative processes. One drawback of these prior art systems is an inability to substantially decompose the organic feedstock. Another drawback of these prior art systems is the amount of coking, tarring and/or charring produced during the process, which builds up within those systems during processing, to limit or preclude flow of material, thereby inhibiting the degree of processing of the organic material and resulting in a considerable amount of downtime for maintenance.

A process for decomposition of organic matter is described in U.S. Patent No. 4,439,209, Wilwerding et ah, which teaches a thermal decomposition apparatus that uses a heated rotating drum inside a furnace to decompose organic matter. A screw-conveyor within an air-tight rotating drum moves the organic matter along a horizontal line, with a heat gradient of 700° F to 1,200° F from input port to exit port. Wilwerding '209 describes several other prior art systems, including "digester" processes, "heater" processes, "mechanical" processes, and "dissolving" processes, which provides additional useful background information to the present invention. U.S. Patent No. 4,872,949, Wilwerding, discloses a process for treating drilling mud known also to be applicable in the processing of organic matter such as used rubber tires. As taught in the '949 patent, spent drilling mud is introduced into a series of horizontally arranged screw conveyors (or "augers") within steel tubes and gradually heated to dry the contaminated mud to effect the separation and removal or organic liquids." In one application, the horizontally aligned screw conveyors are arranged in such a way to cause the vapors coming off the mud to flow in a direction counter-current to the direction of flow of the drilling muds. l U.S. Patent No. 7,621,226, Cauley et al., discloses a "System and Method for Recycling Waste into Energy." The Cauley patent draws from the Wilwerding '209 and '949 patents, and combines the two systems into one heated enclosure comprising: an upper reaction area comprising a series of horizontally aligned screw conveyors in fluid communication with a lower reaction area comprising a heated rotating drum. As is the case of Wilwerding '949, the Cauley patent discloses the flow of gases generated during the heating process counter current to the flow of the solid materials within the system. Also as was the case with Wilwerding '209, the design of the Cauley patent can result in excess tarring, coking and charring within the system, and especially within the area of the rotating drum, thereby resulting in restricted flow of materials to be processed.

Another drawback of the above-discussed prior art systems, and others like them, is that applying the amount of heat necessary to cause decomposition in the case of the Cauley patent and the Wilwerding patent '209, and/or to horizontally aligned screw conveyors in the case of Wilwerding patent '949, can result in deformation of the drum and/or tubes in which pyrolytic and/or ablative decomposition occurs. Deformation of the drums or tubes can cause a number of problems; in particular, causing the mechanical components inside the drums or tubes to bind. Thus, these prior art systems are limited in the amount of heat that may be applied over time and in the amount of time these systems can operate before needing maintenance, which in turn limits the efficiency of the system.

A need therefore exists for a system and apparatus that provides a greater degree of decomposition of organic matter with limited or no coking, tarring or charring. The present invention provides such an improved system and is especially useful in the processing of waste rubber tires, but may also be used to process other organic matter such as coal, oil shale, tar sands, plastics, sewage sludge, refining and manufacturing by- products, industrial process and agricultural wastes and/or by-products, and many others.

Other objects, and the many advantages of the present invention, will be made clear to those skilled in the art in the following description of several embodiment(s) of the invention and the drawings appended hereto. Those skilled in the art will recognize, however, that the embodiment(s) described herein are only examples of specific embodiment(s) and are not the only embodiment(s) of a system and method constructed and/or performed in accordance with the teachings of the present invention. This object is met by providing an improved system for decomposing organic matter and producing certain valuable products that may be operated as a stand-alone unit or used with other prior art systems. In one embodiment, the system includes a thermally insulated enclosure, a reaction vessel within the insulated enclosure, an entry port for the introducing organic matter into the reaction vessel, a substantially round metal surface within the reaction vessel onto which organic matter is introduced, burners within the reaction vessel for heating the metal surface to 500° and 1,400° F, a paddle rotating on a central axis about the heated metal surface to agitate the organic matter deposited on the metal surface, an exit port for discharging solid decomposed materials from the thermally insulated enclosure, and an exit port for exhausting gases generated within the reaction vessel that can then be condensed into liquid products or retained in gaseous forms. The system may be in fluid communication with an upstream system that pre-heats, and initiates the decomposition of, the organic matter before introduction into the system of the present invention. One such upstream system that can be used with the present invention includes as a series of horizontally arranged screw conveyors, which is in fluid communication with the present invention, and which are both contained within a heated enclosure. The system of the present invention may also be duplicated and "stacked" one on top of another, depending upon the application and the degree of decomposition of organic matter necessary.

Referring now to the figures, Figure 1 depicts a side view of a first embodiment of the present invention showing a reaction vessel inside a heated enclosure.

Figure 2 depicts a top plan, partially cutaway view into the reaction vessel of the present invention.

Figure 3 depicts a view of the underside of the reaction vessel of the present invention.

Figure 4 depicts a side view of a paddle for scraping and/or agitation of feedstock deposited onto the hot metal surface.

Figure 5 is a side view of staggered paddles for scraping and/or agitation of feedstock deposited onto the hot metal surface.

Figure 6 is a side view of a central drive hub assembly used to drive the paddle(s) inside the reaction vessel of the present invention. Figure 7 is a side view of another embodiment of the present invention where one reaction vessel is oriented above another reaction vessel within the same heated enclosure, and the two reaction vessels are in fluid communication with one another.

Figure 8 is a side view of another embodiment of the present invention where one reaction vessel of the present invention within its own heated enclosure is oriented above another reaction vessel and its associated heated enclosure, and wherein the two reaction vessels are in fluid communication with one another.

Figure 9 is a side view of another embodiment of the present invention wherein a prior art upper reaction chamber in the form of a series of horizontally aligned augers, for example as described in the above-referenced Wilwerding '949 patent, preheats and initiates the decomposition of the organic matter to be processed and is oriented above a reaction vessel of the present invention, and wherein the upper reaction chamber and lower reaction vessel are in fluid communication with one another.

Figure 10 is a schematic sectional view of another embodiment of the present invention in which the drive system for the paddles for scraping and/or agitation of feedstock deposited onto the hot metal surface is located away from the heat source.

In more detail, the present invention comprises a reaction vessel contained within a heated enclosure, wherein organic matter is decomposed through, generally speaking, a combination of pyrolytic (decomposition of organic matter in a heated enclosure) and ablative (decomposition of organic matter through contact with a heated metal plate) processes. The present invention lends itself especially to decomposition of waste rubber (for example, used rubber tires), although the present invention may also be used to process other organic matter such as coal, oil shale, tar sands, plastics, sewage sludge, and agricultural waste (both plant and animal), garbage, and the organic waste and by- products of various manufacturing processes, among many other types of organic matter.

Referring to Figure 1, a substantially air-tight reaction vessel 1 of the present invention is contained within insulated heated enclosure 2. In the embodiment shown, reaction vessel 1 and heated enclosure 2 are utilized as a stand-alone unit; alternatively, reaction vessel 1 and heated enclosure 2 are used in conjunction with prior art systems as described above (and shown in Fig. 9). Reaction vessel 1 comprises material inlet 3 for introduction of organic matter into reaction vessel 1, vapor outlet 12 for exporting vapors from reaction vessel 1, and a substantially round ablative surface 4 within reaction vessel 1 onto which organic matter is introduced. Vapors removed from reaction vessel 1 through vapor exit 12 are stored in an accumulator for further processing or delivered to a condenser to condense the vapors into a liquid, the condensed liquid representing the product of the process of the present invention. Depending upon the nature of the organic matter to be decomposed, heating element 5 located beneath reaction vessel 1 heats ablative surface 4 to between 1,000° and 1,500° F, and the space above ablative surface 4 to between 700° and 900° F, and provides heat to heated enclosure 2. In the case of organic matter comprising waste rubber tires, for instance, heating element 5 heats ablative surface 4 to between 1,200° and 1,500° F. Paddles 6, comprising paddle arm 7 and scrapers 8, are located inside reaction vessel 1 and are affixed to rotating paddle hub 9. Paddles 6 rotate on a central axis above ablative surface 4 to allow scrapers 8 to scrape and, along with paddle arms 7, agitate the organic matter to be decomposed. Reaction vessel 1 further comprises retaining wall 11 along the perimeter of ablative surface 4 and solids exit 10 for the discharge of decomposed solid materials from reaction vessel 1. Preferably, as scrapers 8 rotate in a circular motion above ablative surface 4, scrapers 8 come in contact with ablative surface 4 and thereby continually clean ablative surface 4. Alternatively, scrapers 8 rotate at a level about 1/8 to 1/4 inch above ablative surface 4. As paddles 6 rotate about ablative surface 4, scrapers 8 agitate organic matter on ablative surface 4, thereby both exposing more organic matter to the environment within reaction vessel 1 for pyrolytic reaction and causing more organic matter to contact ablative surface 4. In the embodiment shown, organic matter to be decomposed is introduced through material inlet 3 onto ablative surface 4 near retaining wall 11. As paddles 6 rotate about ablative surface 4, the processed organic matter gradually builds up on ablative surface 4 and, while being scraped and agitated by paddles 6, exits reaction vessel 1 through solids exit 10 located in proximity to the center of ablative surface 4.

Figure 2 depicts a top view of an embodiment of the present invention with multiple paddles 6. Organic matter is introduced through material inlet 3 onto ablative surface 4. Paddles 6 are located at approximately 180° from one another and are affixed to paddle hub 9. Alternatively, four, six, eight or more paddles 6, or alternatively an odd number of paddles 6, are used to continually scrape ablative surface 4 and agitate the organic matter to be processed as paddles 6 rotate about ablative surface 4. Preferably, however, when multiple paddles 6 are used they are evenly spaced. As paddles 6 rotate about ablative surface 4, the processed organic matter gradually builds up on ablative surface 4 and, while being scraped and agitated by paddles 6, exits from reaction vessel 1 through solids exit 10 located in proximity to the center of ablative surface 4.

Figure 3 is a bottom view of the present invention. Heating element 5 comprises a series of spaced-apart burners 13 and air manifold 14, located in a circular pattern below ablative surface 4, to heat ablative surface 4. Air from air manifold 14, received from outside heated enclosure 2 through air inlet 15, provides air to burners 13. Multiple concentric rows of heating element 5 may also be employed to heat ablative surface 4. Alternatively, the burners 13 of heating element 5 are placed so that an interior portion of ablative surface 4 near rotating hub 9 is hotter than the exterior portion of ablative surface 4 towards the perimeter of ablative surface 4, or vice versa. Figure 4 depicts a side view of paddle 6, in a single scraper design, for scraping and agitating solids deposited onto ablative surface 4. Paddle 6 comprises paddle arm 7 and scraper 8. Preferably, paddle 6 may be affixed to paddle hub 9 by welding, bolting, or any other known fastening means.

Figure 5 is a side view of staggered scrapers 8 in a multiple paddle design where paddles 6 with the respective scrapers 8 alternately scraping and agitating the organic matter to be decomposed. Scrapers 8 extend downwardly from paddle arm 7 and are "staggered" with respect to another paddle such that one paddle 6 passes over ablative surface 4 that is not covered by a previous or subsequent scraper 8. In an embodiment employing two or more paddles 6 such as depicted in Fig. 2 above, the use of staggered scrapers 8 allow for a greater degree of agitation of the organic matter to be decomposed while at the same time assuring a constant cleaning of ablative surface 4.

The paddles 6 and scrapers 8 are provided because, if not agitated or scraped, the carbon residual forms an insulating layer over the heat transfer surface, possibly affecting heat transfer rate and slowing down the pyrolysis reaction. Agitation has the additional effect of reducing temperature gradients within the stirred material.

Figure 6 is a side view of paddle drive hub assembly 16 wherein paddle hub 9 rests above ablative surface 4 within reaction vessel 1. Drive sprocket 18, coupled to and driven by a motor, is mounted to paddle hub drive shaft 17 to rotate paddle hub 9 on bearings 19. Shaft seal 20 and seal spring 21 seals the shaft opening through ablative surface 4 that receives drive shaft 17. Paddle hub 9 is mounted to drive shaft 17, extends into reaction vessel 1, and forms a unitary member with drive hub assembly 16.

Figure 7 is a side view of another embodiment of the present invention where a first reaction vessel la is oriented above a second reaction vessel lb within the same heated enclosure 2, and the two reaction vessels are in fluid communication with one another through tube 22 such that solids from upper reaction vessel la are initially processed in upper reaction vessel la and then dropped into lower reaction vessel lb for further processing, and wherein vapors from the lower reaction vessel lb pass from lower reaction vessel lb to upper reaction vessel la.

Figure 8 is a side view of another embodiment of the present invention where reaction vessel la of the present invention within its own heated enclosure 2a is oriented above a second reaction vessel lb and its associated heated enclosure 2b, and wherein the two reaction vessels are in fluid communication with one another through tube 22 such that solids from upper reaction vessel la are initially processed in upper reaction vessel la and then dropped into lower reaction vessel lb for further processing, and wherein vapors from the lower reaction vessel lb pass from lower reaction vessel lb to upper reaction vessel la, and then exit upper reaction vessel la through vapor outlet 12.

Figure 9 is a side view of another embodiment of the present invention wherein a prior art upper reaction chamber in the form of a series of horizontally aligned augers, for example as described in the Wilwerding '949 patent, preheats and initiates the decomposition of the organic matter to be processed, and is oriented above the reaction vessel 1 of the present invention. The upper reaction chamber and lower reaction vessel 1 are in fluid communication with one another such that solids from the upper reaction chamber are preheated for initial decomposition and then dropped into the lower reaction vessel 1 for further processing, and vapors from the lower reaction vessel 1 pass from the lower reaction vessel 1 to the upper reaction chamber and exit the upper reaction chamber through an exit port in the upper reaction chamber.

Referring now to Figure 10, upper reaction chambers in the form of horizontally aligned augers are shown schematically above a lower reaction vessel 1 , the material to be decomposed dropping down from the upper reaction chambers through inlets 3 onto heated metal ablative surface 4. A plurality of scrapers 8, each formed as an inverted "T" and supported from the arm 7, agitates and scrapes the material deposited onto the surface 4 as the material decomposes by application of heat from the burners 13 of heating element 5. Decomposed material is gradually worked upwardly and outwardly from the center of ablative surface 4 by action of the scrapers 8 mounted on the rotating arm 7 and drops from the reaction vessel 1 through exit port 10. As will be apparent from a review of Fig. 10, the vessel 1 is curved upwardly with the lowest part of ablative surface 4 at the center, and the exit port 10 is located at a height on the upward curve that causes the material to be decomposed to accumulate in sufficient volume and reside on ablative surface 4 for sufficient time to insure complete decomposition before dropping through exit port 10. Paddle/scraper design and speed of rotation likewise affects the volume and residence time of the material such that the location of outlet port 10 relative to the center of ablative surface 4 can be accommodated by varying operating parameters. Paddle drive hub assembly 16 is as described in the above embodiments but, as can be seen by comparison of Fig. 10 to Figs. 1 - 9, is located on the side of surface 4 opposite the heat element 5, thereby providing improved access to the mechanical components, lowering the temperatures to which the components of assembly 16 are subjected, and improving performance and reliability.

The process of the present invention produces the above-described carbon residue and, if the vapors are condensed and depending upon the nature of the organic material introduced into the reaction vessel, a valuable liquid by-product useful as a solvent for many industrial processes. The reaction vessel is provided with various sealing systems on the feedstock inlet and product outlets as known in the art and, although usually conducted as a continuous process, is not open to the atmosphere. In one embodiment, the method is conducted under a slight vacuum (inches of water column) relative to ambient pressure, the primary source of the vacuum being the collapse of solvent vapors in water-cooled condensers, but a vacuum pump (not shown) may also be provided to remove non condensable gases. Although minimal air ingress into the reaction vessel can be tolerated, it is preferred that air leakage not be allowed to overwhelm the vacuum pump used to maintain the slight negative pressure on the reaction system. As noted above, the reaction vessel is heated by heating element 5 to temperatures at which the ablative surface 4 reaches a temperature of between 1,000° and 1,500° F and the space above ablative surface 4 to between 700° and 900° F. When the reaction vessel of the present invention is combined with a prior art upper reaction chamber in the form of a series of horizontally aligned augers such as described in the Wilwerding '949 patent and shown in Fig. 9, above, the lower chamber is heated to a temperature in the range of 800° - 1100° F and the upper chamber to a temperature of 600° - 900° F.

Residence time within the reaction vessel is in the range of 15 to 30 minutes depending upon the nature of the organic material to be decomposed as determined by experimentation and in accordance with the general knowledge of those skilled in the art. For instance, if used tires are introduced into the reaction vessel, it is suggested in the literature that tire pyrolysis follows first order decomposition reaction kinetics with the rate of reaction doubling every 18° to 20° F increase in temperature. The reaction is fairly endothermic and reaction rate is limited by intra-particle heat transfer (the ability to transfer heat within the tire particle) at the normal operating temperatures of the reaction vessel. The polymers that make up tire rubber all have different rate constants and heat transfer rates that may require different residence times, but the polymer that requires the longest residence time controls the overall residence time for that particular feedstock (and with many other organic feedstocks as can be determined by experimentation). Residence time can be increased by increasing the diameter of the reaction vessel 1, locating the exit port at a higher point on the curved surface (n the case of a reaction vessel having an upwardly-curved ablative surface such as is shown in Fig. 10) changing the speed and/or configuration of the paddles and scrapers as suggested above, and in other ways that will become clear to those skilled in the art from the operation of the apparatus of the present invention.

Those skilled in the art who have the benefit of this disclosure will recognize that changes can be made to the component parts of the apparatus of the present invention without changing the manner in which those parts function and/or interact to achieve their intended result. All such changes are intended to fall within the scope of the following, non-limiting claims.

Claims

WHAT IS CLAIMED IS:

1. Apparatus for decomposing organic matter comprising:

a reaction vessel comprising:

an entry port for introduction of organic matter into the reaction vessel;

a heated metal surface within the reaction vessel onto which organic matter is introduced;

at least one paddle inside the reaction vessel and mounted to a drive shaft for rotating about the metal surface to agitate the organic matter thereon;

an exit port for discharging solid materials from the reaction vessel; and

an exit port for exhausting gases from the reaction vessel;

burners located beneath said reaction vessel for heating the metal surface; and

a motor for rotating the drive shaft to rotate the paddle.

2. The apparatus of claim additionally means for condensing the vapors exhausted from said reaction vessel.

3. The apparatus of claim 5 wherein said reaction vessel is substantially airtight.

4. The apparatus of claim 1 wherein said reaction vessel is substantially airtight.

5. The apparatus of claim 4 additionally comprising a vacuum pump for decreasing the pressure in said reaction vessel to a pressure below atmospheric pressure.

6. The apparatus of claim 1 wherein the exit port is located near the center of the metal surface and the paddle gradually moves organic matter deposited onto the metal surface toward the exit port for discharge from said reaction vessel.

7. The apparatus of claim 1 wherein the metal surface is curved upwardly from a lowest point at the center, the exit port being located at a point on the upward curve thereof and the paddle gradually moves organic matter deposited onto the metal surface toward the exit port for discharge from said reaction vessel.

8. A method of decomposing organic matter comprising the steps of heating a metal surface located in a reaction vessel to a temperature of

1000° - 1500° F;

introducing organic matter to be decomposed into the reaction vessel and onto the heated metal surface;

agitating the organic matter deposited onto the heated metal surface; and after the organic matter has been agitated on the heated metal surface for sufficient time to effect ablation of the organic matter, moving the ablated organic matter to an exit port for exiting the reaction vessel.

9. The method of claim 8 wherein the reaction vessel is heated to a temperature of 700° - 900° F.

10. The method of claim 8 additionally comprising exhausting any vapors produced during ablation of the organic matter from the reaction vessel.

11. The method of claim 10 additionally comprising the step of condensing the vapors exhausted from the reaction vessel.

12. The method of any of claims 8 - 11 wherein the pressure in the reaction vessel is lower than ambient pressure.

13. The method of claim 8 wherein organic matter introduced into the reaction vessel resides on the heated metal surface for 15 - 30 minutes.