TECHNICAL FIELD

The present invention relates generally to machinery, devices and related methods useful for transforming polymeric materials, including solid biomass and waste plastics, into a plurality of liquid reaction products by way of supercritical water reaction. The green technology disclosed herein enables the economic utilization of abundant biomass and waste plastics as viable renewable feedstocks (as opposed to feedstocks derived from fossil fuels) for conversion into alternative liquid transportation fuels and valuable green-chemical products.

BACKGROUND OF THE INVENTION

The potential of utilizing lignocellulosic biomass and waste plastics as viable feedstocks for conversion into liquid transportation fuels and other green-chemical products is now well recognized. Unfortunately, most existing biomass and waste plastic conversion schemes tend to focus on either traditional thermochemical (pyrolysis and acid hydrolysis) or biological (enzyme attack) pretreatment regimes and are, therefore, believed to be inefficient from a modern chemical engineering perspective. There exists, however, another very promising new approach that utilizes the amazing transformational properties of “supercritical water” (SCW) to rapidly depolymerize and liquefy giant biomass and/or waste plastic molecules into valuable simple sugar solutions and/or oily hydrocarbon mixtures, both of which are key chemical intermediates (commodities) that, in turn, are desirable products for makers of alternative transportation fuels (refiners) and green-chemical products (chemical companies). Indeed, and in recent years, two such green-chemical products producers have emerged in the marketplace; namely, Renmatix, Inc. (King of Prussia, Pa.) and Licella Pty Ltd. (New South Wales, Australia). Both of these newly emergent green technology companies utilize conventional slurry pumping (conveying) and static flow-through SCW reactor technologies to treat various biomass and/or waste plastic material feedstocks via supercritical water reaction. Conventional slurry pumps and static flow-through SCW reactors, however, require the transport (conveyance), heating and pressuring of great excesses of water in order to operate properly. The transport (conveyance), heating, and pressurizing of excess water is energetically and economically unfavorable.

With regards to the processing of waste plastics (and polystyrene in particular), another green-chemical product (crude oil from waste plastics) producer that has also recently emerged is Agilyx, Inc. (Portland, Oreg.). Agilyx describes itself as an “environmental technology and development company that extracts value from difficult-to-recycle mixed plastic waste streams.” To this end, Agilyx has purportedly developed a system capable of converting mixed waste plastics into a high-quality crude oil product (which, in turn, is sold to a local petroleum refinery (Tacoma, Wash.) for blending and subsequent refining). In brief, Agylix's technology may best be described as a modified pyrolysis process in which mixed waste plastics are first heated to form hydrocarbon gases, which gases are then subsequently condensed back into liquid form (thereby creating a hydrocarbon oil from what was once plastic). Because the unmitigated breaking (scission) of carbon-carbon bonds (of the polymeric material) via pyrolysis yields pairs of highly reactive free-radicals, a significant amount of char is necessarily formed (as the various sized free-radicals quickly bond and condense back together). The formation of any char products is undesirable because char is a useless solid material with no (or negative) commercial value.

Because of recent governmental initiatives to combat global warming and reduce domestic reliance on foreign petroleum products (through the development of alternative green energy and renewable chemical sources), and because of a strong societal desire to find alternative uses for biomass and waste plastics, the market potential for an alternative green technology platform that can rapidly transform biomass and/or waste plastics into liquid fuel and green-chemical products is believed to be unparalleled.

Accordingly, and although some progress has been made with respect to biomass and waste plastic materials conversion technologies, there is still a need in the art for new and improved biomass and/or waste plastic conversion machines, systems and related methods. There is also a need for transportable (by land or sea) machinery and methods that enable continuous supercritical water reaction of solid polymeric materials with minimal water usage and with changeable (tunable) residence times to thereby allow processing of a wide variety of different mixed polymeric feedstocks. The present invention fulfills these needs and provides for further related advantages.

SUMMARY OF THE INVENTION

In brief, the present invention in an embodiment is directed to a machine for transforming one or more selected polymeric feedstock materials (such as a solid biomass and/or waste plastic material) into a plurality of reaction products via supercritical water reaction. The inventive machine disclosed herein comprises (1) an extruder having an inlet and a downstream outlet, wherein the downstream outlet is coincident with the longitudinal axis of the extruder; (2) a steam generator fluidically connected to a downstream inlet manifold, wherein the inlet manifold forms a ring having a plurality of inwardly facing exit portals, wherein the plurality of exit portals is circumferentially positioned about the inner surface of the ring; and (3) a tubular reactor having an interior space fluidically connected to an inlet end and an outlet end (of the tubular reactor), wherein the inlet end of the tubular reactor is adjacent and fluidically connected to both (i) the outlet of the extruder, and (ii) the plurality of circumferentially positioned exit portals of the inlet manifold. In addition, the outlet end of the tubular reactor is fluidically connected to (at least) a first downstream chamber.

The inventive machine in other embodiments further comprises a movable (adjustably extendable) ram centrally positioned within the tubular reactor. The ram (which may take the form of a rod and is sometimes referred to as a “spear”) is movable back and forth within and along the longitudinal axis of the tubular reactor to thereby increase or decrease the volume of the interior space of the tubular reactor. In this way, the residence time of the supercritical water reaction occurring within the tubular reactor (during operation of the machine) may be selectively and readily changed (with longer residence times corresponding to larger reactor volumes).

In accordance with the biomass and/or waste plastic material liquefaction methods disclosed herein, a specialized single screw extruder is utilized to convey, while heating and increasing pressure from atmospheric to about or greater than 3,200 psi, a selected low-water content solid biomass and/or waste plastic feedstock material from an upstream hopper to a downstream tubular reactor. The selected feedstock material becomes heated, pressurized, and plasticized/moltenized (i.e., turns into a molten state) while travelling down the heated barrel of the extruder before exiting through a specialized extruder outlet (or die). The extruder outlet, in turn, is fluidically connected to an adjacent inlet manifold that, in turn, includes a plurality of circumferentially positioned and inwardly directed exit ports. The exit ports are configured to circumferentially inject supercritical or high-energy water into the tubular reactor and impinge upon the molten feedstock material (that is flowing centrally therethrough during operation of the machine). A novel cone-shaped occlusion (having a plurality of reactant flow through-holes positioned about a base plate of the cone portion) is centrally positioned and axially aligned at the reactor's frontend to facilitate spreading and thinning of the centrally flowing molten feedstock material (as the material flows over the cone), thereby enabling the near-instantaneous penetration and mixing of the centrally flowing molten feedstock material with regulated (or minimum) amounts of supercritical/high-energy water.

The reaction time within the variable volume flow-through SCW reactor may be, in some embodiments, controlled by adjustably and/or selectively positioning the ram (centrally positioned within the tubular reactor and sometimes referred to as a “spear”) to either contract (“ram-in”) or expand (“ram-out”) the volume of the otherwise tubular reaction chamber. In other embodiments, the length of the ram is preselected and nonadjustable.

In still further embodiments, a circumferentially positioned, high efficiency alternating current induction coil (that is part of an induction heater) surrounds the tubular reactor and supplies additional heat energy when needed (for example, to maintain steady state conditions during operation of the machine). Similarly, a plurality of outer heating bands is positioned about the barrel of the extruder for preheating the selected feedstock material (as the material travels down the barrel of the extruder). In this way, a minimum amount of water is conveyed, heated, pressurized and used for reaction and liquefaction. Moreover, the reaction (residence) time may be appropriately adjusted (tuned) to accommodate different types of polymeric material feedstocks.

These and other aspects of the present invention will become more evident upon reference to the following detailed description and accompanying drawings. It is to be understood, however, that various changes, alterations, and substitutions may be made to the specific embodiments disclosed herein without departing from their essential spirit or scope.

