NZ719158B2 - Apparatuses and methods for controlling heat for rapid thermal processing - Google Patents

Abstract

Disclosed is a method for controlling heat for rapid thermal processing of carbonaceous biomass material or wood to produce charcoal. The method for processing a moisture-containing carbonaceous feedstock comprises contacting the moisture-containing carbonaceous feedstock with heated air to form a reduced-moisture carbonaceous feedstock. The reduced-moisture carbonaceous feedstock is pyrolyzed to form char; and combusting the char and transferring a portion of the combustion heat to an air stream to form the heated air. educed-moisture carbonaceous feedstock. The reduced-moisture carbonaceous feedstock is pyrolyzed to form char; and combusting the char and transferring a portion of the combustion heat to an air stream to form the heated air.

Description

Patents Form No. 5 N.Z. No. 719158 Divided out of Application No. 622535 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION APPARATUSES AND METHODS FOR CONTROLLING HEAT FOR RAPID THERMAL PROCESSING We, Ensyn Renewables, Inc. of Brandywine Plaza, West Building 1521 Concord Pike, Suite 205A gton, Delaware 19803-3645 UNITED STATES OF A do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- (followed by page 1A) THERMAL PROCESSING This ation is a divisional application of New Zealand patent application no. 622535. -1A- (Followed by page 2) they are mixed together and travel upward through the reactor. In particular, the heated inorganic solid particulates transfer heat to pyrolyze the carbonaceous al forming char and gaseous products including high quality pyrolysis gas, which are removed from the reactor to a cyclone. The cyclone separates the gaseous products and solids (e.g. inorganic solid ulates and char), and the solids are passed to the reheater.

The er is a vessel that burns the char into ash and reheats the inorganic solid particulates, which are then returned to the reactor for pyrolyzing more carbonaceous material. An oxygen-containing gas, lly air, is supplied to the reheater for burning the char. The inorganic solid particulates and char are contained in the lower portion of the reheater and are fluidized by the air, forming a fluidized bubbling bed also referred to as the dense phase. The reheater also has a dilute phase that is above the dense phase and comprises ily flue gas, entrained inorganic particles, and ash, which are the byproducts formed from combusting the char with the air. The flue gas, entrained nic particles, and ash are removed from the reheater to a cyclone which separates the solids from the flue gas.

Currently, higher capacity RTP arrangements are desired that are capable of handling carbonaceous feedstock rates of up to 400 bone dry metric tons per day (BDMTPD) or higher ed to usly lower feedstock rates of less than 100 . The increased capacity results in more char being produced in the RTP reactor, and the RTP er and auxiliary equipment (e.g. cyclone, air blower, etc.) need to be larger in size to support the increased feedstock rate. In particular, many newer RTP reheaters require additional volume to accommodate additional air supplied to the reheaters for cooling to control the otherwise rising temperatures from burning the onal char, and can have sizes of up to 12 meters (m) or greater in diameter and s of up to 25 m or greater. Unfortunately, the larger sizes of these ers substantially increase the cost and complexity of shipping, installing, and operating the reheaters.

Accordingly, it is desirable to provide apparatuses and methods for controlling heat for rapid thermal processing that can adequately support higher carbonaceous feedstock rates without exceeding the design temperature of the reheater from burning the additional char. Moreover, it is also desirable to e apparatuses and methods for controlling heat for rapid thermal processing without substantially increasing the cost and complexity of shipping, installing, and operating the reheaters. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the ed claims, taken in conjunction with the accompanying drawings and this ound of the ion.

SUMMARY OF THE INVENTION Apparatuses and methods for controlling heat for rapid thermal processing of carbonaceous al are provided herein. In accordance with an exemplary embodiment, an apparatus for controlling heat for rapid thermal processing of carbonaceous material comprises a reheater configured to contain a fluidized bubbling bed that comprises an oxygen-containing gas, inorganic heat r particles, and char and to operate at combustion conditions effective to burn the char into ash and heat the inorganic heat carrier particles to form heated nic particles. An inorganic particle cooler is in fluid communication with the reheater to receive a first portion of the heated inorganic particles and is configured to e a cooling medium for indirect heat exchange with the first portion of the heated inorganic particles to form first partially-cooled heated nic particles. The reheater and the nic particle cooler are cooperatively configured to combine the first partially-cooled heated inorganic particles with a second portion of the heated inorganic particles in the reheater to form second partially-cooled heated inorganic particles. A reactor is in fluid communication with the er to receive the second partially-cooled heated nic particles.

In accordance with another exemplary embodiment, an apparatus for controlling heat for rapid thermal processing of carbonaceous material is provided. The apparatus comprises a reactor and a reheater that is in fluid communication with the reactor to receive inorganic heat carrier particles and char. The er is configured to form a ed bubbling bed that comprises an oxygen-containing gas, the inorganic heat carrier les, and the char and to operate at combustion conditions effective to burn the char into ash and heat the inorganic heat carrier particles to form heated inorganic particles. An inorganic particle cooler is in fluid communication with the reheater and comprises a shell portion and a tube portion that is disposed in the shell portion. The inorganic particle cooler is red such that the tube portion receives a n of the heated inorganic particles and the shell portion receives a cooling medium for indirect heat exchange with the portion of the heated inorganic particles to form partially-cooled heated inorganic particles that are fluidly communicated to the reheater.

The above embodiment of the invention is claimed in the parent application NZ 622535.

Other embodiments of the invention may be claimed in one or more divisional applications. A description of them is retained herein for clarity and completeness.

In accordance with another exemplary embodiment, a method for controlling heat for rapid thermal processing of carbonaceous material is provided. The method comprises the steps of combining an oxygen-containing gas, inorganic heat carrier particles, and char at tion conditions ive to bum the char into ash and heat the inorganic heat carrier particles to form heated inorganic particles. Heat from a first portion of the heated inorganic particles is indirectly exchanged to a cooling medium to form first partially-cooled heated inorganic particles. The first lly-cooled heated inorganic particles are combined with a second portion of the heated inorganic particles to form second partially-cooled heated inorganic particles. [0010A] In accordance with r exemplary ment, a method for processing a moisture-containing carbonaceous feedstock is provided. The method comprises the steps of contacting the moisture-containing carbonaceous feedstock with heated air to form a reducedmoisture carbonaceous feedstock, pyrolyzing the d-moisture carbonaceous feedstock to form char; and combusting the char and transferring a portion of the combustion heat to an air stream to form the heated air.

BRIEF DESCRIPTION OF THE GS Embodiments of the present invention will hereinafter be bed in conjunction with the ing drawing figures, wherein like numerals denote like elements, and wherein: tically illustrates an apparatus for rapid thermal processing of carbonaceous al in accordance with an exemplary embodiment; 4 (Followed by page 4A) is a partial sectional view of the apparatus ed in including an nic particle cooler in accordance with an exemplary embodiment; and is a nal view of the inorganic particle cooler depicted in along line 3-3.

DETAILED DESCRIPTION The following Detailed Description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding Background of the Invention or the following Detailed Description. 4A (Followed by page 5) Various embodiments contemplated herein relate to apparatuses and methods for controlling heat for rapid l processing of aceous material. Unlike the prior art, the exemplary embodiments taught herein provide an apparatus sing a reactor, a reheater that is in fluid communication with the r, and an inorganic particle cooler that is in fluid communication with the reheater. The reactor y pyrolyzes a carbonaceous feedstock with heated inorganic les to form gaseous products and solids that include cooled inorganic heat carrier particles and char. A cyclone separates the gaseous products from the solids. The reheater receives the solids and fluidizes the cooled inorganic heat carrier les and char with an oxygen-containing gas to form a fluidized bubbling bed. The reheater is operating at tion conditions effective to burn the char into ash and reheat the cooled inorganic heat carrier particles to form heated inorganic particles.

In an exemplary embodiment, a portion of the heated inorganic particles and a cooling medium are fluidly communicated to the inorganic particle cooler. Some of the heat from the heated inorganic particles is indirectly exchanged with the cooling medium to partially cool the heated inorganic particles, forming a heated cooling medium and first lly-cooled heated inorganic particles. The heated cooling medium is removed from the inorganic particle cooler. The first partially-cooled heated inorganic particles are fluidly communicated to the reheater and combined with the ing portion of the heated inorganic particles to partially cool the heated inorganic particles, forming second partially-cooled heated inorganic particles. The second partially-cooled heated inorganic particles are fluidly communicated to the reactor for continued rapid pyrolysis of the carbonaceous feedstock. The inventors have found that partially cooling the heated inorganic particles with the inorganic particle cooler facilitates controlling the temperatures from excessively rising in the reheater even if the fluidized bubbling bed contains higher levels of char. Accordingly, the reheater does not require additional volume that would otherwise be needed to odate additional air for cooling to l the reheater temperatures and therefore, the cost and xity of shipping, installing, and operating the reheater is not substantially impacted.

[0018] Referring to a schematic depiction of an apparatus 10 for rapid thermal processing of a aceous material in accordance with an exemplary embodiment is provided. The apparatus 10 ses an upflow transport reactor 12, a reheater l4, and an inorganic particle cooler 15. The reactor 12 is configured for achieving a relatively high temperature within a m amount of time as well as providing a relatively short residence time at the high temperature to affect fast pyrolysis of a carbonaceous feedstock (e.g. biomass including biomass waste). The vely high temperature is achieved in a lower portion 16 of the reactor 12 using heated inorganic heat carrier particles 18 (e.g., heated sand) that are supplied from the reheater 14 to drive the pyrolysis process.

As illustrated and will be discussed in further detail below, a dryer 13 removes water from a moisture-containing aceous feedstock 11 to form a aceous feedstock 20 that preferably has a moisture content of 6 weight percent (wt. %) or less.

The carbonaceous feedstock 20 is supplied to a feed bin 22 where a reactor feed conveyor 24 introduces the carbonaceous feedstock 20 to the lower portion 16 of the reactor 12. A carrier gas 25, which can be a recirculation gas collected from a suitable location along the apparatus 10, is also introduced to the lower portion 16 of the reactor 12. The carrier gas preferably contains less than 1 wt. % of oxygen, and more preferably, less than 0.5 wt. % of oxygen so that there is very little or no oxygen present thus minimizing or preventing oxidation and/or combustion of the carbonaceous feedstock 20 in the reactor 12.

Rapid mixing of the heated inorganic heat carrier particles 18 and the carbonaceous feedstock 20 occur in the lower n 16 of the reactor 12. As the mixture advances up the r 12 in turbulent flow with the r gas 25, heat is transferred from the heated inorganic heat r particles 18 to the carbonaceous feedstock 20. In an exemplary embodiment, mixing and rapid heat transfer occurs within 10% of the desired overall reactor resident time. Accordingly, the mixing time is preferably less than 0.1 seconds, and more preferably within 0.015 to 0.030 s. In an exemplary ment, the temperature in the lower portion 16 of the r 12 is from 600 to 780°C, and the heating rate of the carbonaceous feedstock 20 is ably 1000°C per second or greater. The use of sand or other suitable inorganic particulate as a solid heat carrier enhances the heat transfer because of the higher heat carrying capacity of the inorganic particles, and the ability of the inorganic particles to mechanically ablate the e of the reacting carbonaceous material.

[0021] As the heated mixture is carried towards an upper portion 17 of the reactor 12 with the r gas 25, fast pyrolysis of the carbonaceous ock 20 occurs. In an exemplary embodiment, the temperature in the upper portion 17 of the reactor 12 is from 450 to 600°C. The sand or other inorganic heat carrier particles and the carrier gas 25, along with product vapors 30 and char form a product stream 26 that is d out of the upper portion 17 of the r 12 to a cyclone 28. The cyclone 28, preferably a reverse flow cyclone, removes the solids 32, e.g., sand and char, from the product vapors 30, which comprise the r gas 25, non-condensible product gases and the primary condensible vapor products. The t vapors 30 are removed from the cyclone 28 and passed to a Quench Tower (not shown), for example, for rapid cooling or quenching to preserve the yields of the valuable non-equilibrium ts in the product vapors 30. The solids 32 are removed from the cyclone 28 and passed to the reheater 14.

[0022] The reheater 14 receives an oxygen-containing gas 34, which is typically air.

The solids 32 are contained in a lower portion 36 of the reheater l4 and are ed by the oxygen-containing gas 34 from a gas distributor 86 (see to form a fluidized bubbling bed of char, inorganic heat carrier particles, and the oxygen-containing gas 34.

The reheater 14 is ing at combustion conditions to burn the char into ash and flue gas. The energy released from combustion of the char reheats the nic heat carrier particles to form heated inorganic particles. In an exemplary embodiment, the heated inorganic particles have a temperature of from 600 to 780°C.

The flue gas, entrained sand, and ash rise to an upper portion 37 of the reheater l4 and are carried out of the reheater 14 as an exhaust stream 41 to a cyclone 43. The cyclone 43, preferably a reverse flow cyclone, removes the sand and ash from the flue gas.

The flue gas is passed along as a gas stream 51 for exhausting, subsequent sing, recirculation, or a combination thereof, and the sand and ash are passed along as a solids- containing stream 49 for disposal or subsequent processing.

Referring also to in an exemplary embodiment, a portion of heated inorganic particles 38 is removed from the reheater l4 and introduced to the inorganic particle cooler 15. As rated, the portion of heated inorganic particles 38 is removed from the lower portion 36 of the reheater 14 and passed along a cooler inlet pipe 40 through at least one bubble breaking g 39 to an exchanger vessel 42. The bubble breaking grating 39 breaks up any larger bbles, for example, from the fluidized inorganic particles that otherwise may be passed along countercurrent to the portion of heated inorganic particles 38, back up to the bubbling bed at the lower portion 36 of the er 14. Big bubbles in the fluidized bed affect the reheater's 14 performance and solid entrainment. The bubble breaking grating 39 also serves as a screener to prevent bigger chunks of material, such as refractory from ly blocking or plugging the tube portion 45 and reducing the inorganic particle cooler capacity.

In an exemplary embodiment, the exchanger vessel 42 is configured as a heat exchanger and comprises a shell portion 44 and a tube portion 45 that is disposed in the shell portion 44. The n of the heated nic particles 38 is passed through the tube portion 45. The shell portion 44 of the exchanger vessel 42 receives a cooling medium 52 for indirect heat exchange with the portion of heated nic particles 38 passing through the tube portion 45 to form partially-cooled heated inorganic particles 54 and a heated cooling medium 53. In an exemplary embodiment, the partially-cooled heated inorganic les 54 have a temperature of from 500 to 680°C.

Preferably, the cooling medium 52 comprises air and the heated cooling medium 53 comprises heated air. As illustrated in the heated cooling medium 53 (e. g. heated air) may be passed along to the dryer 13 for removing water from the moisture- containing carbonaceous feedstock 11. Alternatively, the cooling medium 52 may be any other thermally conductive fluid known to those skilled in the art. Preferably, the cooling medium 52 has a temperature of 40°C or less, and the heated cooling medium 53 has a ature of 125°C or greater.

Referring to in an exemplary embodiment, the tube portion 45 comprises a plurality of tubes 58 that are juxtaposed, spaced apart, and longitudinally disposed substantially el to a vertical axis. Each of the tubes 58 has an outer surface with one or more cooling fins 60 that can extend, for example, radially or longitudinally outward from the outer e. The cooling fins 60 facilitate indirect heat exchange n the portion of the heated inorganic les 38 advancing through the tube portion 45 and the cooling medium 52 advancing through the shell portion 44.

As illustrated in the partially-cooled heated inorganic particles 54 are removed from the exchanger vessel 42 and passed along a cooler standpipe 73. The cooler standpipe 73 has an ion slide valve 74 for controlling the flow rate of the partially-cooled heated inorganic particles 54. A lift riser 76 is downstream from the exchanger vessel 42 and is fluidly coupled to the cooler standpipe 73 for receiving the lly-cooled heated inorganic particles 54. Disposed in a lower portion 78 of the lift riser 76 is an air nozzle 80 that is configured to direct the partially-cooled heated inorganic particles 54 through the lift riser 76 to an upper portion 82 of the lift riser 76.

A ir distributor 84 is disposed in the reheater l4 and is fluidly coupled to the lift-riser 76 to receive the partially-cooled heated inorganic particles 54. The sand-air distributor 84 is red to distribute the partially-cooled heated nic les 54 in the reheater 14, preferably above the gas distributor 86, to partially cool the remaining portion of the heated inorganic particles and form the heated inorganic heat carrier particles 18. Referring also to in exemplary embodiment, the heated inorganic heat carrier particles 18 have a temperature of from 600 to 780°C and are passed along to the reactor 12 for rapidly pyrolyzing additional carbonaceous material.

Accordingly, apparatuses and methods for controlling heat for rapid thermal sing of carbonaceous material have been described. Unlike the prior art, the exemplary embodiments taught herein provide an apparatus sing a reactor, a reheater, and an inorganic particle . The reactor rapidly pyrolyzes a carbonaceous feedstock with heated inorganic particles to form pyrolysis oil and solids that include cooled inorganic heat carrier particles and char. The reheater es the solids and fluidizes the cooled inorganic heat r les and char with an oxygen-containing gas to form a fluidized bubbling bed. The reheater is operating at combustion conditions effective to burn the char into ash and heat the cooled nic heat r particles to form heated inorganic particles. The inorganic particle cooler es a portion of the heated inorganic particles and removes some of the heat via indirect exchange to form partially-cooled heated inorganic particles that are combined with the ing portion of the heated inorganic particles to partially cool the heated inorganic particles. It has been found that partially cooling the heated inorganic particles with the nic particle cooler facilitates controlling the temperatures from excessively rising in the reheater even if the fluidized bubbling bed contains higher levels of char. Accordingly, the reheater does not require additional volume that would otherwise be needed to accommodate additional air for cooling to control the er temperatures and therefore, the cost and complexity of shipping, installing, and operating the reheater is not substantially impacted.

[0031] While at least one exemplary embodiment has been presented in the foregoing Detailed Description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not ed to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing Detailed Description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the ion, it being tood that various changes may be made in the fianction and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended Claims and their legal equivalents.

Claims (21)

Claims: What is claimed is:

1. A method for processing a moisture-containing carbonaceous feedstock, comprising: i) contacting the re-containing carbonaceous feedstock with heated air to form a reduced-moisture carbonaceous feedstock; ii) pyrolyzing the reduced-moisture carbonaceous feedstock to form char; and iii) combusting the char and transferring a portion of the combustion heat to an air stream to form the heated air.

2. The method of claim 1, wherein the moisture-containing aceous feedstock is a biomass.

3. The method of claim 1, n the reduced-moisture carbonaceous feedstock has a water content of 6 wt.% or less.

4. The method of claim 1, wherein the char is combusted in a reheater in the presence of inorganic particles to form heated inorganic les.

5. The method of claim 4, said transferring sing: ucing a portion of the heated inorganic particles and the air stream into a heat exchanger.

6. The method of claim 5, said pyrolyzing comprising: introducing the reducedmoisture carbonaceous feedstock to a lower portion of a fast pyrolysis upflow reactor.

7. The method of claim 5, wherein said portion of heated inorganic particles are recirculated from the heat exchanger into the reheater and a second portion of the heated inorganic particles are communicated from the reheater to said lower portion of the reactor.

8. The method of claim 5, wherein said portion of the heated inorganic particles enter the heat exchanger at a temperature in the range of 600 to 780 °C and exit the heat exchanger at a temperature in the range of 500 to 680 °C.

9. The method of claim 8, n said portion of heated nic particles are recirculated from the heat exchanger into the er and a second portion of the heated inorganic particles are communicated from the reheater to said lower portion of the reactor.

10. The method of claim 1, wherein the heated air is at a temperature of at least 125 °C.

11. The method of claim 1, wherein the air stream is at a temperature of 40 °C or less.

12. The method of claim 1, said pyrolyzing comprising: introducing the reducedmoisture carbonaceous feedstock to a lower portion of a fast pyrolysis upflow

13. The method of claim 12, wherein the lower portion of the reactor is at a temperature in the range of 600 to 780 °C.

14. The method of claim 12, wherein an upper portion of the reactor is at a temperature in the range of 450 to 600 °C.

15. The method of claim 12, said introducing comprising: mixing the feedstock with inorganic particles in a ygen carrier gas, said inorganic particles at an initial temperature in the range of 600 to 780 °C.

16. The method of claim 15, wherein the mixing occurs under turbulent flow conditions.

17. The method of claim 16, wherein the mixing has a mixing time of less than 0.1 seconds.

18. The method of claim 16, wherein the mixing occurs within 10% of a desired reactor residence time.

19. The method of claim 15, wherein said reduced-moisture carbonaceous feedstock is heated at a rate of greater than 1000 °C per second in said lower portion of the reactor.

20. The method of claim 15, wherein the low oxygen carrier gas has an oxygen t of less than 1 wt.%.

21. A method according to claim 1, substantially as herein described or ified. ENSYN RENEWABLES, INC. By their Attorneys HENRY HUGHES IP Per: