Production of oil by pyrolysis of coal

Abstract

Catalysts useful in transforming biomass to bio-oil are disclosed, as are methods for making such catalysts, and methods of transforming biomass to bio-oil. The catalysts are especially useful for, but are not limited to, microwave- and induction-heating based pyrolysis of biomass, solid waste, and other carbon containing materials into bio-oil. The catalysts can also be used for upgrading the bio-oil to enhance fuel quality.

Claims

1. A method of producing oil from coal by pyrolysis; said method comprising the steps of: (a) cleaning the surface of one or more metallic substrate particles, wherein each metallic substrate particle has a longest dimension between about 100 m and about 5 mm; (b) oxidizing or nitriding the surfaces of the metallic substrate particles, to covalently attach oxide or nitride groups to the surfaces of the metallic substrate particles; (c) covalently bonding one or more linker groups to the oxide, to the nitride, or to the metal surface; (d) covalently bonding one or more seed layers to the one or more linker groups, wherein the one or more seed layers comprise ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, copper, rhenium, mercury, aluminum oxide, or nickel(II) oxide; (e) covalently bonding a catalyst layer to the one or more seed layers, wherein the catalyst layer comprises a metal, a metal oxide, a doped metal, or a zeolite; wherein the resulting catalyst/support composition is adapted to directly absorb electromagnetic energy from microwave irradiation, or electromagnetic induction, or both, and thereby to be rapidly heated to a temperature between about 250 C. and about 1000 C.; (f) heating the catalyst/support composition to a temperature between about 250 C. and about 1000 C. by microwave irradiation, or by electromagnetic induction, or both, in an inert atmosphere inside a reactor; (g) contacting coal with the heated catalyst/support composition for a time sufficient to transform at least a portion of the coal into oil vapors; wherein the catalyst/support composition is hotter than the coal; and (h) condensing the oil vapors, and collecting the resulting liquid oil.

2. The method of claim 1, additionally comprising the step of heating the catalyst/support composition to a temperature between about 250 C. and about 1000 C. in an inert atmosphere, wherein the stability of the catalyst is enhanced by said heating.

3. The method of claim 1, wherein said contacting step is conducted as a continuous process.

4. The method of claim 1, wherein said contacting step is conducted as a batch process.

5. The method of claim 1, wherein hydrogen gas, water, or water vapor is mixed with the coal over the heated catalyst/support composition; and wherein the hydrogen gas, water, or water vapor provides hydrogen atoms that are incorporated into the resulting oil molecules.

6. The method of claim 1, additionally comprising the step of separating a gasoline fraction or a diesel fraction from the oil.

7. The method of claim 1, wherein said condensing step employs a quencher and an electrostatic precipitator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts temperature plots for the heating of stainless steel particles, both with and without surface-deposited Pt.

(2) FIG. 2 depicts an XPS spectrum for Pt on stainless steel.

(3) FIGS. 3A and 3B depict flowcharts for pyrolysis systems for bio-oil production.

(4) FIG. 4 depicts a generalized system for biomass pyrolysis.

(5) FIG. 5 depicts the reduction in biomass weight as a function of time at different pyrolysis reaction temperatures.

(6) FIG. 6 depicts the dependence of char, water, and bio-oil yields on pyrolysis temperature.

(7) FIGS. 7A-7E depict gas chromatographs for bio-oil produced at different pyrolysis temperatures.

(8) FIG. 8 depicts the water content of the liquid fraction of tested bio-oil samples.

(9) FIG. 9 depicts the dependence of the yield of three gases on pyrolysis temperature.

(10) FIG. 10 depicts the liquid yield for different biomass sources at various pyrolysis temperatures.

(11) FIG. 11 depicts the solid (char) yield for different biomass sources at various pyrolysis temperatures.

(12) FIG. 12 depicts the gas yield for two biomass sources at various pyrolysis temperatures.

(13) FIG. 13 depicts the carbon content of char after pyrolysis of two biomass sources at various temperatures.

(14) FIG. 14 depicts the hydrogen content of char after pyrolysis of two biomass sources at various temperatures.

(15) FIG. 15 depicts the nitrogen content of char after pyrolysis of two biomass sources at various temperatures.

(16) FIGS. 16, 17, and 18 depict liquid, char, and gas yields for PSW pyrolysis at various biomass-to-catalyst ratios and temperatures.

(17) FIG. 19 depicts the water (aqueous phase) and bio-oil (non-aqueous phase) yield of pyrolysis bio-oil at different B/C ratios at 370 C.

(18) FIG. 20 depicts the water (aqueous phase) and bio-oil (non-aqueous phase) yield of pyrolysis bio-oil at different B/C ratios at 330 C.

(19) FIG. 21 depicts the water (aqueous phase) and bio-oil (non-aqueous phase) yield of pyrolysis bio-oil at different B/C ratios at 290 C.

(20) FIG. 22 depicts gas chromatograms (M count) for bio-oil samples from a non-upgraded sample (using HZSM-5).

(21) FIG. 23 depicts gas chromatograms (K count) for bio-oil samples from an upgraded sample (using HZSM-5).

MODES FOR CARRYING OUT THE INVENTION

Methods

Abbreviations

(22) TABLE-US-00001 B/C ratio Biomass-to-catalyst ratio BTEX Benzene, toluene, ethyl benzene, and xylene CEL Cellulose CHN Carbon, hydrogen, and nitrogen CTT Chinese tallow tree biomass EDS Electron Dispersive X-ray Spectroscopy FTIR Fourier Transform Infrared Spectroscopy GC Gas chromatography MS Mass spectroscopy PSW Pine sawdust SEM Scanning Electron Microscopy XPS X-ray Photoelectron Spectroscopy XRD X-ray Diffraction Spectroscopy

Example 1. Catalyst/Substrate Production

(23) A Pt-stainless steel substrate was produced by chemically reducing Pt(s) from platinum salt onto the surfaces of stainless steel particles. The deposition process used formaldehyde as the reducing agent, sodium hydroxide as a stabilizing agent, and chloroplatinic acid hexahydrate solution as the platinum source.

(24) Stainless steel particles (type 316, diameter 4.8 mm) were first washed with deionized water and ethanol, and then dried in an oven at 100 C. The surface of the stainless steel was then plasma-oxidized for 30 sec in vacuum, chemically converting the metal surface into its oxide. This primed the surface for coupling with a silane linker, which acted as a coupling agent between organic and inorganic materials. The silane linker was formed by hydrolyzing alkoxy groups in the molecule to form a silanol. The hydroxyl groups were then hydrogen-bonded to the substrate, releasing water molecules.

(25) The silane linker used in an initial prototype was a thiol-functionalized silane, mercaptomethyl methyl diethoxy silane (C.sub.6H.sub.16O.sub.2SSi), purchased from Gelest, Inc.; it was applied following the manufacturer's instructions. After the stainless steel particle surfaces had been oxidized, the particles were submerged in a 2% silane solution (95% ethanol solvent) and agitated for about 2 to 3 min. The solution was decanted, and the particles were rinsed with ethanol. They were either dried overnight at room temperature, or dried for 15 minutes in a 100-150 C. oven. This process was repeated using stainless steel foil to run Fourier Transform Infrared Spectroscopy (FTIR) to confirm silane bonding to the stainless steel surface.

(26) Peaks for SiO-metal (1000-900 cm.sup.1), SiOSi (1130-1000 cm.sup.1), SiCH.sub.3 (1275-1245 cm.sup.1), CH (3000-2700 cm.sup.1), and some OH (3000-3500 cm.sup.1) were observed. The SH peak was relatively weak and difficult to detect.

(27) The silanized stainless steel particles were then submerged in a gold nanoparticle solution for seeding. The energetically favorable adsorption of thiol to Au nanoparticles created nucleation sites for potential Pt growth. The steel particles were agitated in the Au nanoparticle solution for a few minutes and then left overnight. The next day, the solution was decanted; and the particles were rinsed gently with deionized water and dried in an oven.

(28) A 20 mM aqueous solution of H.sub.2PtCl.sub.6 was prepared and mixed with the stainless steel balls. The pH was raised to 12 with 0.1 M sodium hydroxide. The solution was then heated to approximately 90 C. with vigorous stirring. Then excess formaldehyde (36.5%) was added at a 10:1 molar ratio relative to PtCl.sub.4.sup.2. The solution changed color as the platinum was reduced.

(29) The platinum-functionalized steel particles were then cleaned as otherwise outlined in Tang, Xiaolan et al, Structural Features and Catalytic Properties of Pt/CeO.sub.2 Catalysts Prepared by Modified Reduction-Deposition Techniques, Catalysis Letters 4th Ser., Vol. 97, no. 3, pp. 163-170 (2004), and the particles were then rinsed with hot deionized water until the filtrate tested negative with 0.1 M silver nitrate solution (i.e., no silver chloride precipitation was observed); followed by overnight heating in oven at 150 C. The stainless steel balls were then allowed to cool before they were used in the induction heater.

(30) In an alternative embodiment, H-ZSM-5 catalyst-coated particles were prepared by modifying the methods for producing conformal coatings on stainless steel and cobalt-silicon substrates as described by Louis, B. et al., Synthesis of ZSM-5 coatings on stainless steel grids and their catalytic performance for partial oxidation of benzene by N2O. Applied Catalysis A: General 2001, 210 (1-2), 103-109; and Aboul-Gheit, A. K. et al., Effect of hydrochlorination and hydrofluorination of Pt/H-ZSM-5 and Pt-Ir/H-ZSM-5 catalysts for n-hexane hydroconversion. Applied Catalysis A: General 2008, 334 (1-2), 304-310. The coating methods employed low-temperature, hydrothermal synthesis of sol-gels. Briefly, stainless steel or cobalt substrates were cleaned and plasma-oxidized as otherwise described above. After the plasma oxidation step, the particles were transferred to a silane solution to form a monolayer interface coating. After the monolayer had formed, the particles were washed in ethanol, and then transferred to a solution of TEOS, TPA, and AIP for the formation of the sol-gel. Following gel formation the reaction mixture was heated for 24-48 hours to promote H-ZSM-5 formation. The coatings are characterized by electron microscopy, x-ray photoelectron spectroscopy, x-ray diffraction and optical emission spectroscopy to confirm morphology, crystal structure and metal composition. As another alternative, platinum-substituted versions are prepared by ion exchange, by analogy to the ion-exchange procedure described in Aboul-Gheit, A. K. et al. (2008).

Example 2. Catalyst Analysis After Induction Heating

(31) The platinum-functionalized stainless steel balls were heated with an induction heater at a higher frequency (150 to 400 kHz) at three different power levels: 150 W (3%), 250 W (5%) and 350 W (7%). Thermal characteristics were compared to those of untreated stainless steel balls. Three stainless steel balls (functionalized or untreated) were placed in a ceramic crucible and heated inside the induction coil during each run.

(32) Temperature plots compared steel balls with Pt to steel balls without Pt at three power levels: 3%, 5%, and 7% (output=5 kW), as a function of time. As illustrated in FIG. 1, only minor differences in temperature profiles were observed; the platinum deposition did not substantially alter the temperature reached by the stainless steel balls when heated with an induction coil. The temperature profiles were fitted to a simple exponential curve, with three parameters (T.sub.0, a, and b):
T(K)=T.sub.0+a*(1b.sup.t(s))

(33) The heating parameters and maximum steady state temperatures reached at different conditions are listed in Table 1.

(34) TABLE-US-00002 TABLE 1 Induction heater parameters. Max Steady State Power Frequency Current Voltage Temperature (K.) (W) (kHz) (A) (V) Control w/Pt 150 [3%] 335 21 70 815 23 798 24 250 [5%] 333 23 86 926 22 941 19 350 [7%] 331 25 104 1083 22 1152 43

(35) Before heating, the surfaces of the stainless steel balls were analyzed with Electron Dispersive X-ray Spectroscopy (EDS). The resulting data showed that the Pt on the surface averaged approximately 62 wt %. X-ray Photoelectron Spectroscopy (XPS) was carried out using stainless steel foil as a substitute for the stainless steel balls. Binding energies were calibrated using the Fe2p peak (BE=70.9 eV) as a reference. FIG. 2 shows the XPS spectrum for Pt-4f.

(36) The platinum nanoparticles on the surfaces of the stainless steel particles were imaged via Scanning Electron Microscopy (SEM) (data not shown). The images showed crystalline and spherical nanoparticle formation, along with aggregation. The surfaces of the stainless steel balls with Pt were analyzed again after heating. We observed that nanoparticles had melted at the higher heating levels.

Example 3. Systems for Induction Pyrolysis

(37) One embodiment of the present invention employed the catalyst in an induction heating system (RDO-LF model no. 5-35/100-3). A range of temperatures from 400 C. to 800 C. was tested to determine the effect on liquid pyrolysis yield. The induction heater was a low frequency model (RDO Induction LLC, Washington, N.J.) operated in the range 35-100 kHz using a 5 kW power supply. The reaction tube was a 310-stainless steel tri-clamp tube, 419 mm length, 34.4 mm inner diameter, and 38.1 mm outer diameter. An outlet with a 16.5 mm inner diameter was located 29.4 mm from the end of the reaction tube connected to the inlet airflow. The system was purged of oxygen using a continuous flow of argon gas at 1 L/min.

(38) FIG. 3a schematically depicts a prototype embodiment of the pyrolysis setup. The induction coil was a ten-loop, rubber-coated copper coil with an overall length of 285 mm and an inner diameter of 59 mm. The reaction tube temperature was monitored by an Omega iR2C series infrared laser controller (Omega, Stamford, Conn.). The controller adjusted the power of the RDO induction heater using a 0-10 V signal. The collection system comprised five condensation columns, through which mineral oil circulated at a temperature of 5 C. The columns were fitted to flasks to collect the condensed liquids. Uncondensed gasses were passed through ethanol and liquid filters before venting.

(39) A second embodiment of the system improved the linearity of the process, reduced cost, and improved collection of the liquid bio-oil product. An outlet on the side of the tube was removed, and the reaction products flowed directly into the condensation flasks. This configuration addressed the problem of char residue buildup within the outlet joint, which would otherwise require more frequent cleaning. Argon gas was replaced with nitrogen gas. No significant difference in performance is expected between argon and nitrogen. Both are inert gases as used in this process, and nitrogen is generally less expensive. Modifications were also made to the condensation and collection components. The condensation columns were removed since they were difficult to clean, which also made it difficult to quantify any remaining oil left on their surfaces. The condensation columns were replaced by one individual collection flask submerged in an ice bath. To compensate for the lower surface area, an electrostatic precipitator was designed using a custom-made glass cylinder that tapered into a 34/40 ground glass fitting. A steel cylinder was inserted into a glass tube and attached to a ground wire through the rubber cap, and a steel rod was inserted through the cap and attached to the power supply. The power supply could operate between 0 and 20 kV, and was typically run at 120 V. These modifications both improved liquid yields and improved ease of use. FIG. 3b depicts a flowchart of the modified pyrolysis system used in the experiments of Example 6.

Example 4. Generalized System for Biomass Pyrolysis

(40) FIG. 4 depicts a third embodiment, a generalized system for biomass pyrolysis. Biomass (or other carbon-containing solid feedstock, e.g., coal) is fed from the hopper into the pyrolysis chamber using an auger/motor system. Depending on the moisture content and particle size of the feedstock, drying and milling of the feedstock before pyrolysis is optional.

(41) The electromagnetically heated pyrolysis chamber (i.e., the reactor) is flashed (or purged) with nitrogen gas to remove oxygen.

(42) Hydrogen gas or other hydrogen donor fluid (gas or liquid) can be added to the reactor to improve bio-oil quality. It is desirable to make the bio-oil product as close as possible to a petroleum-equivalent or to a finished product (e.g., gasoline, diesel, etc.)

(43) The biomass (or other carbon-containing solids) are heated inside the pyrolysis chamber. In the absence of oxygen, the material does not burn. Instead it is volatilized and pyrolyzed from larger molecules, especially long-chain polymers such as cellulose or lignocellulose, to produce smaller molecules. Three types of products are produced: (1) volatile compounds (volatile, that is, at the pyrolysis temperature) which can subsequently be condensed into a liquid at room temperature; (2) non-condensable gases (e.g. CH.sub.4, CO, CO.sub.2, and H.sub.2)these gases can optionally be used as a heat source in a heat exchanger or as a secondary feedstock in a burner to generate heat and electricity; and (3) charcarbon, high molecular weight compounds that are not volatilized, ash, and other residual solids.

(44) In the electromagnetically heated catalyst bed, the volatile liquid and gas compounds are further processed in the presence of the catalyst to alter their composition, and particularly to remove oxygen. Were coal (or another low-oxygen source material) used instead of biomass, then water or steam could be added to the reaction mixture as a low-cost hydrogen source. Depending on the selected catalyst and the specific processing conditions in the catalyst bed, different products can be obtained, including gasoline, diesel, and other valuable compounds. The undergo subsequent purification in a stream separator. (The separator may be a separator such as is otherwise known in the art.)

(45) A quencher and electrostatic precipitator (ESP) are used to condense gases into liquid. Compounds that are not condensed can be dissolved in solvent traps. For example, in one embodiment there are two solvent trapsone uses water or other polar solvent, and the other uses a non-polar solvent. Dissolved compounds can later be separated from the solvents. Any non-condensable, insoluble gases that pass through the traps (e.g., CH.sub.4, CO, CO.sub.2, H.sub.2, etc.) can be used to generate heat and electricity.

(46) In most if not all previous methods of producing bio-oil, the catalyst bed has been heated externally, which tends to lead to clogging when gases repolymerize on the catalyst surface or on reactor walls. By contrast, in preferred embodiments of the present invention, the catalyst bed is hotter than the gas stream, which causes gases to tend to move away from the catalyst surface and walls, thus reducing clogging and catalyst poisoning.

Example 5. Methods for Induction Pyrolysis

(47) Two sets of experiments were run using induction heating (FIG. 3a). Experiment 1 was a time-versus-temperature experiment used to determine the time needed to essentially complete the conversion of biomass at various temperatures. Experiment 2 was the pyrolysis of pine sawdust (PSW) at different operating temperatures to quantify and analyze the chemical composition of the bio-oil fraction.

(48) The procedures for these experiments were as follows. First, 30 grams of PSW feedstock were weighed and packed in the center of the reaction tube. The tube was then placed in the induction coil, supported by wooden blocks. One end of the tube was attached to the inlet argon gas flow, and the other to the gas outlet, which connected to the condensing system. The flow rate of argon was 1 L/min.sup.1. The system was purged with argon for 20 min to lower oxygen levels below 1%. The operating temperature was set on an infrared PID controller, and the system was operated for 10-minute increments. After 10 minutes, the system was cooled and the char remaining in the reaction tube was weighed. The char was then reinserted into the reaction tube, and the process was repeated until no further significant change was recorded in the char mass. The temperatures tested to determine complete reaction times were 400 C., 500 C., 600 C., 700 C., and 800 C. A type-K thermocouple was placed in the outlet port to determine whether the internal temperature differed from the temperature observed by the infrared controller on the reaction chamber surface (no notable differences were observed).

(49) For the second experiment, the reaction time was set at 60 min for 400 C., 40 min for 500 C., 30 min for 600 C., and 20 min for both 700 C. and 800 C. Gas samples were collected for analysis once the system reached the respective operating temperature. The condensed liquids were collected from the flasks, weighed, and analyzed. The yields of liquid and char were calculated from the measured weights of the collected materials, divided by the initial biomass weight; the difference represented the presumptive gas yield.

(50) Before analysis the bio-oil samples were mixed well. A 1 mL sample was removed and added to 2 mL of 99% pure hexane (Sigma Aldrich). The sample and solvent were mixed thoroughly to maximize the extraction of soluble compounds. The samples were allowed to separate for 15 minutes, and the hexane fraction was decanted for further analysis. The hexane-soluble fraction was analyzed by gas chromatography/mass spectroscopy (GC-MS). 1-L samples were manually injected into the GC with a syringe.

(51) The gas samples were analyzed to determine the content of combustible and incombustible gasses (CO, CO.sub.2, and CH.sub.4), using a SRI 6610C Gas Chromatograph equipped with a FID, ECD, and TCD. A Varian Saturn 2200 Ion Trap MS had a 3800 GC attached. The system used a DB5 column. The water content of the liquid fraction was determined using a Karl-Fischer moisture titrator (Metrohm Model 831 KF Coulometer), with triplicate measurements to ensure accurate readings.

Example 6. Comparison of Materials in Induction Pyrolysis

(52) A third experiment compared several biomass feedstock materials under the same operating conditions as the first two experiments, to determine the effects of the type of biomass on the resulting products.

(53) This experiment used the system depicted in FIG. 3b, with an electrostatic precipitator and a linear reaction tube. Pine sawdust (PSW), cellulose (CEL), and Chinese tallow tree wood (CTT) were tested at temperatures ranging from 500 C. to 700 C. at 50 C. increments. The yields of char and bio-oil were determined by weight, and the difference was presumed to represent the gas fraction.

(54) GC-MS was performed using a Shimadzu GC 2010 with dichloromethane as the solvent. The ratio of solvent to bio-oil was 5:1. Samples were compared to a reference standard containing 100 ppm BTEX (benzene, toluene, ethyl benzene, and xylene). Separately, the liquid and char samples were analyzed with an elemental analyzer (Perkin Eimer 2400 Series 2 CHNS/O) to determine carbon, hydrogen, and nitrogen (CHN) content of the samples. Samples of either char or liquid were weighed and sealed in small tin containers. These containers were placed in the elemental analyzer, and the contents were combusted under oxygen gas flow.

(55) The pyrolysis and upgrading experiments were conducted in two separate induction heating machines. Three samples of biomass (PSW, lignin, and CEL) were studied, both during and after pyrolysis. The biomass samples were heated in an RDO induction heater, low frequency model (RDO Induction LLC, Washington, N.J.), operated in the range 35-100 kHz, using a 5 kW power supply. The reaction tube was a 310-stainless steel tri-clamp tube, 419 mm long, 34.4 mm inner diameter, and 38.1 mm outer diameter. An outlet with a 16.5 mm inner diameter was located 29.4 mm from the end of the reaction tube attached to the inlet airflow. The system was purged of oxygen using a continuous flow of nitrogen gas at 1 L/min for 20 min.

(56) The induction coil was a ten-loop, rubber-coated copper coil with an overall length of 285 mm and an inner diameter of 59 mm. The reaction tube temperature was controlled with an Omega iR2C series infrared controller (Omega, Stamford, Conn.). An infrared laser monitored the temperature, and the power of the RDO induction heater was modified based on the temperature data feedback. The reaction temperature for PSW and lignin was 550 C., while that for CEL was 500 C. These temperatures were chosen based on preliminary experiments.

(57) The vapors from reactor 1 were passed over an HZSM-5 catalyst inside a 2.54 cm ID stainless tube. This tube was heated with a second induction heater. Three biomass-to-catalyst (B/C) ratios (1:1, 1:1.5, and 1:2) were studied; and three temperatures (290 C., 330 C., and 370 C.) were studied at each B/C ratio. The catalyst was used twice for each combination of ratio and temperature, to measure the extent of catalyst deactivation. The resulting vapors were condensed in a round bottom flask in an ice bath. The remaining vapors were passed through an electrostatic precipitator to collect remaining condensable gases. The bio-oil was collected and refrigerated at 20 C. to inhibit polymerization reactions. Gas samples were also collected for analysis.

(58) Liquid, gas, and char yields were quantified. Oil and char samples were analyzed for C, H, N, and O content using a Perkin-Elmer 2400 elemental analyzer. Gas samples were analyzed for C.sub.1-C.sub.5 hydrocarbon, CO.sub.2, and CO composition. Water content in the liquid samples was measured by Karl-Fisher titration. BTEX composition analysis used a GC-FID by Shimadzu with a BTEX standard. GC-MS used a Varian 1200 series for product identification. The catalyst was studied using X-ray Diffraction (XRD) and XPS, both before and after reaction. SEM images of catalysts and biomass were taken both before and after the reaction. The catalyst surface area was measured with the surface analyzer.

(59) Preferred methods for catalytic upgrading include hydrodeoxygenation, and zeolite cracking followed by dehydration. Hydrodeoxygenation may be carried out, for example, with commercial Ni catalysts, AIMCM, or amberlyst. HZSM-5 is a preferred zeolite catalyst. HZSM-5 is dielectric, which means that is readily heated by microwave irradiation. Commercial Ni catalysts showed good activity in processing biomass-derived liquids, and they were readily regenerated. Metal/metal oxide catalysts can be used to convert smaller, oxygenated molecules into larger molecules containing less oxygen. Metal/metal oxide catalysts can also be used to deoxygenate phenols. Solid base catalysts tended to reduce acidity of bio-oils. Overall, HZSM-5 gave the highest aromatic hydrocarbon yields of any catalyst we have tested to date.

Results

Example 7. Results from Induction Pyrolysis Without Upgrading

(60) Char weights from incrementally timed reactions were examined to determine both the biomass conversion rate and the total time required to completely convert the biomass. Results showed a markedly shorter time for complete conversion of the biomass as the reaction temperature increased. The final char mass declined as temperature increased from 400 C. to 800 C. FIG. 5 shows the reduction of biomass weight as a function of time for different reaction temperatures.

Example 8. Characterization of the Liquid Fraction from Example 5

(61) The products of the PSW pyrolysis of Example 5 were examined to determine the effects of temperature on the yield of the fractions produced, and the changes in composition of the fractions. Char yield declined as temperature increased from 400 C. to 800 C., with increasing conversion of biomass at higher temperatures. The incremental decline in char mass was less pronounced at 600-800 C. (25.6-21.0%) than at 400-500 C. (39.1-29.4%). Total liquid yield (bio-oil and water) increased at 400-500 C. (27.6-36.5%), but then remained stable from 500-800 C. (insignificant changes, with less than 1% variation.) This leveling off could be the result of the loss of uncondensed molecules with smaller molecular weights that would be expected at higher temperatures. FIG. 6 shows the dependence of char, water, and bio-oil yields on the pyrolysis temperature at a temperature-dependent holding time, an argon flow rate of 1 L/min, and a condensation temperature of 5 C.

(62) The hexane-extracted fraction of the bio-oil was analyzed by GC-MS to identify the organic compounds generated by pyrolysis. FIGS. 7A-7E show the chromatographs from different pyrolysis temperatures, showing the presence of numerous compounds in varying concentrations. There was little variation in the peak patterns, suggesting that the temperature has less effect on the quality of the oil than it does on the quantity. Pyrolysis products from PSW were a complex mixture of organic compounds that made identification and quantification of specific organic molecules quite challenging. Using computerized search capabilities, probable compounds in the bio-oil sample were tentatively identified. Individual peaks in FIGS. 7A-7E are labeled to correspond to the rows having the same numbers in Table 2. The compounds identified in the sample were consistent with what would be expected for a non-upgraded pyrolytic bio-oil. Many aromatic and oxygenated organic compounds were seen, including various ketones and phenols.

(63) TABLE-US-00003 TABLE 2 GC-MS compounds identified in pine sawdust (PSW) pyrolysis samples at different temperatures. The numbering in the table corresponds to that in FIGS. 7A-7E. Peak Time.sup.a Chemical no. min. Compound Composition 1 5.55 Ethylbenzene C.sub.8H.sub.10 2 6.15 Styrene C.sub.8H.sub.8 3 6.55 1-(2-furanyl)ethanone C.sub.6H.sub.6O.sub.2 4 7.4 5-methyl-2-furancarboxaldehyde C.sub.6H.sub.6O.sub.2 5 7.7 Phenol C.sub.6H.sub.6O 6 8.5 Indene C.sub.9H.sub.9 7 8.65 p-Cresol C.sub.7H.sub.8O 8 8.95 m-Cresol C.sub.7H.sub.8O 9 9.1 Guaiacol C.sub.6H.sub.6O.sub.2 10 9.33 2,4-dimethylphenol C.sub.8H.sub.10O 11 9.65 2-ethylphenol C.sub.8H.sub.10O 12 9.8 3,5-dimethylphenol C.sub.8H.sub.10O 13 10 4-ethyl-phenol C.sub.8H.sub.10O 14 10.7 4-ethyl-3-methyl phenol C.sub.9H.sub.12O 15 10.75 3,4-dimethoxytoluene C.sub.9H.sub.12O.sub.2 16 10.8 1-ethyl-4-methoxybenzene C.sub.9H.sub.12O 17 11.2 4-ethylguaiacol C.sub.9H.sub.12O.sub.2 18 11.55 2-methoxy-4-vinylphenol C.sub.9H.sub.10O.sub.2 19 11.85 Eugenol C.sub.10H.sub.12O.sub.2 20 12 4-propylguaiacol C.sub.10H.sub.14O.sub.2 21 12.4 Isoeugenol C.sub.10H.sub.12O.sub.2

(64) Karl-Fischer titration was performed to determine the water content of the liquid fraction of the tested samples. As shown in FIG. 8, water content was highest at 400 C. and lowest at 600 C. There was a downward trend in water content from 400 C. to 600 C., followed by a slight upward trend from 600 C. to 800 C. However, the overall water content (43.3-53.5%) was fairly high in all cases. For most applications, water should be removed from the bio-oil product before it is used as a fuel.

Example 9. Characterization of the Gas Fraction from Example 5

(65) Gas samples were analyzed by GC to determine the presence of combustible and incombustible gases (CO, CO.sub.2, and CH.sub.4) that could have value as secondary products. Analyses showed that the concentration of combustible gasses increased as the pyrolysis temperature increased from 400 C. to 800 C. The combustible nature of these gases and their increasing concentration as the temperature increased suggested a more complete breakdown of biomass at higher temperatures. FIG. 9 shows gas concentrations (CO, CO.sub.2, and CH.sub.4) as a function of pyrolysis temperature.

Example 10. Yield Data from Example 6

(66) Liquid, char, and gas yields from three different biomass sources (PSW, CTT, and CEL) were compared at five different pyrolysis temperatures, ranging from 500 C. to 700 C. in 50 C. increments. FIG. 10 shows a slight upward then downward trend for the liquid yields from PSW and CTT as temperature increased, and a steady downward trend for the liquid yield from CEL. FIG. 11 shows a declining trend in char yield as the temperature increased from 500 C. to 700 C. FIG. 12 shows the yield of uncondensed gases. As the temperature increased, the gas yield increased.

Example 11. Characterization of the Solid Fraction from Example 6

(67) Char samples from each experiment were collected at the end of the pyrolysis process. These samples were weighed and tested with a CHN elemental analyzer. FIGS. 13, 14, and 15 show the carbon, hydrogen, and nitrogen content, respectively, of the remaining char after pyrolysis at various temperatures. FIG. 13 shows a slight upward trend of the percentage of carbon within the remaining char as temperature increased. This increase could be due to the removal of other elements (nitrogen, oxygen, and hydrogen) at higher reaction temperatures. FIG. 14 depicts the hydrogen content of the char fraction. There was a prominent declining trend as temperature increased, with more complete removal of hydrogen at higher temperatures. FIG. 15 shows a declining trend in nitrogen content of the char from the pyrolysis of CTT as temperature increased, but an increasing trend of nitrogen from PSW.

Example 12. Results from Induction Pyrolysis with Upgrading

(68) FIGS. 16, 17, and 18 show the change in liquid, char, and gas yields for PSW at three biomass-to-catalyst (B/C) ratios (1:1, 1:1.5, and 1:2) and three temperatures (370 C., 330 C., and 290 C.). The dotted lines depict the same catalyst when used in a second run at same B/C ratio and temperature combination. It was generally observed that the liquid yield decreased with catalytic upgrading. For example, the liquid yield from PSW without catalytic upgrading (50-55%) declined to 35-45% with upgrading. The highest liquid yield was achieved at the highest temperature, with a maximum yield of 45.4% at 370 C. and a B/C ratio of 1:1. The lowest liquid yield was 27% at 290 C. and a B/C ratio of 1:2. In most cases, the liquid yield increased when the same catalyst was reused for a second run, perhaps due to coke deposition on the catalyst surface, leading to partial deactivation of catalyst. Deactivated catalyst does not support the cracking reaction as well, so the liquid yield increased. Liquid yield also decreased as the B/C ratio increased at all temperatures. At higher B/C ratios, high molecular weight compounds were broken down to lower molecular weight fractions and gases. With increased B/C ratios, the gas yield tended to increase.

(69) Pyrolysis of PSW with upgrading produced 45-65% aqueous-phase liquid, primarily comprising water, alcohols, and ketones. Catalytic upgrading removed oxygen in the form of water, carbon dioxide, and carbon monoxide. FIGS. 19, 20, and 21 show the water (aqueous phase) and bio-oil (non-aqueous phase) yields for pyrolysis at different B/C ratios and reaction temperatures (370 C., 330 C., 290 C.). The amount of water increased as the catalyst concentration increased at all temperatures, as we expected if greater amounts of oxygen were removed. No specific trend was observed across different temperature ranges.

(70) Table 3 shows the carbon, hydrogen, and oxygen analysis of bio-oil samples. Bio-oil tends to volatize at room temperature, which made makes precise CHNO analysis difficult. Errors in weight may have led to spuriously increased oxygen values. Oxygen content decreased as the B/C ratio increased. No specific relationship was observed for temperature change.

(71) TABLE-US-00004 TABLE 3 Carbon, hydrogen, and oxygen analysis of bio-oil samples. B/C Carbon Hydrogen Oxygen Temperature ratio % % % 370 1 55.6 2.9 41.5 370 1.5 60.5 2.5 37.0 370 2 69.5 1.9 28.6 370 1 54.5 3.2 42.2 370 1.5 67.7 2.4 29.9 370 2 65.4 2.6 32.0 330 1 62.5 1.9 35.6 330 1 57.0 2.5 40.5 330 1.5 63.2 2.4 34.4 330 1.5 64.9 2.0 33.1 330 2 47.2 2.9 49.9 330 2 66.7 2.1 31.2 290 1 55.3 2.7 42.0 290 1 69.1 1.9 29.0 290 1.5 68.7 1.8 29.4 290 1.5 66.5 2.0 31.5 290 2 65.8 2.0 32.1 290 2 71.5 1.6 27.0

(72) FIGS. 22 and 23 show gas chromatograms for bio-oil samples from non-upgraded and upgraded samples, respectively (using HZSM-5). The presumptive compounds that correspond to the peak numbers shown in FIGS. 22 and 23 are listed in Table 4. Bio-oil vapors were upgraded over an HZSM-5 catalyst in an induction heater at 370 C. PSW was pyrolyzed at 550 C. for 45 min for both upgraded and non-upgraded samples. The upgraded samples had high concentrations of BTEX compounds, and lower concentrations of phenols and mequinol. Non-upgraded bio-oil contained almost no BTEX compounds, and was primarily composed of phenols. The peak area for phenols was lower for upgraded bio-oil, suggesting that catalysis had increased deoxygenation reactions. Various catalyst amounts, operating temperatures, and flow rates will be tested to determine optimal conditions to favor BTEX formation.

(73) TABLE-US-00005 TABLE 4 Compounds corresponding to the numbered peaks in FIGS. 22 and 23. Peak No. Compound Name 1 Benzene 2 Toluene 3 3-methyl-furan 4 Ethylbenzene 5 o-xylene 6 2 cyclopenten-1-one 7 1,2,3 trimethylbenzene 8 1-ethynyl-4-methylbenzene 9 Mequinol 10 2-methoxy-4-methylphenol 11 4-ethyl-1,3-methylphenol 12 4-ethyl-1,3-methylphenol 13 Eugenol 14 1,2-methoxy-4-(1-propyl)-phenol 15 Furan

Example 13. Results from Microwave Pyrolysis

(74) Similar experiments and analyses will be conducted with microwave pyrolysis. Results are expected to be broadly similar, although not identical, to those for induction-heating pyrolysis.

(75) The complete disclosures of all references cited in this specification are hereby incorporated by reference in their entirety, as are the complete disclosures of the three priority applications: U.S. provisional applications Ser. Nos. 61/838,565, 61/839,081, and 62/013,020; as well as the complete disclosures of all references cited in the priority applications. In the event of an otherwise irresolvable conflict, however, the disclosure of the present specification shall control.