Heavy Fossil Hydrocarbon Conversion and Upgrading Using Radio-Frequency or Microwave Energy
20180237704 ยท 2018-08-23
Inventors
- James J. Strohm (Allison Park, PA, US)
- Benjamin Q. Roberts (Seven Fields, PA, US)
- Tricia D. Smurthwaite (Pasco, WA, US)
- Theresa M. Bergsman (Richland, WA, US)
- Mark D. Bearden (Richland, WA, US)
Cpc classification
B01J19/0093
PERFORMING OPERATIONS; TRANSPORTING
H05H1/46
ELECTRICITY
B01J2219/1239
PERFORMING OPERATIONS; TRANSPORTING
B01J2219/00835
PERFORMING OPERATIONS; TRANSPORTING
B01J2219/1245
PERFORMING OPERATIONS; TRANSPORTING
B01J2219/00792
PERFORMING OPERATIONS; TRANSPORTING
C10G15/08
CHEMISTRY; METALLURGY
B01J2219/1227
PERFORMING OPERATIONS; TRANSPORTING
C10G1/002
CHEMISTRY; METALLURGY
C10G29/205
CHEMISTRY; METALLURGY
B01J19/088
PERFORMING OPERATIONS; TRANSPORTING
B01J2219/0894
PERFORMING OPERATIONS; TRANSPORTING
B01J2219/0086
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
Conversion of heavy fossil hydrocarbons (HFH) to a variety of value-added chemicals and/or fuels can be enhanced using microwave (MW) and/or radio-frequency (RE) energy. Variations of reactants, process parameters, and reactor design can significantly influence the relative distribution of chemicals and fuels generated as the product. In one example, a system for flash microwave conversion of HFH includes a source concentrating microwave or RF energy in a reaction zone having a pressure greater than 0.9 atm, a continuous feed having HFH and a process gas passing through the reaction zone, a HFH-to-liquids catalyst contacting the HFH in at least the reaction zone, and dielectric discharges within the reaction zone. The HFH and the catalyst have a residence time in the reaction zone of less than 30 seconds. In some instances, a plasma can form in or near the reaction zone.
Claims
1: A method for selectively preparing paraffins from heavy fossil hydrocarbons (HFH), the method comprising: providing reactants to a reaction zone, the reactants comprising HFH, catalyst, and methane; exposing the reactants in the reaction zone to microwave or RF energy, the exposing selectively converting at least a portion of the HFH to paraffins; and recovering at least the paraffins from the reaction zone.
2: The method of claim 1, wherein the catalyst comprises one or more of iron, char, and/or a promoter of dielectric discharge.
3: The method of claim 1, wherein the pressure in the reaction zone is from between 0.9 atm and 7 atm.
4: The method of claim 1, wherein the reactants are exposed within the reaction zone for residence time from between 5 milliseconds and 30 seconds.
5: The method of claim 1 wherein the paraffins comprise straight chained hydrocarbons.
6: The method of claim 1 wherein the exposing selectively converts the HFH to paraffins rather than aromatic hydrocarbons.
7: A method for converting aromatic hydrocarbons of heavy fossil fuel (HFH) to alkylated aromatic hydrocarbons, the method comprising: providing reactants to a reaction zone, the reactants comprising HFH, catalyst, and methane, wherein the HFH comprises aromatic hydrocarbons; exposing the reactants in the reaction zone to microwave or RF energy to form a product, the exposing selectively converting at least a portion of the aromatic hydrocarbons to methylated aromatic hydrocarbons; and recovering at least a portion of the product from the reaction zone, the portion of the product comprising at least a portion of the alkylated aromatic hydrocarbons.
8: The method of claim 7, wherein the reactants are exposed within the reaction zone for residence time from between 5 milliseconds and 30 seconds.
9: The method of claim 7, further comprising separating a flowable portion of the product from a remainder of the product, the flowable portion of the product comprising alkylated aromatic hydrocarbons and paraffins.
10: The method of claim 9 wherein the remainder of the product comprises unflowable aromatic hydrocarbons.
11: A method for selectively preparing paraffins from heavy fossil hydrocarbon (HFH), the method comprising: providing reactants to a reaction zone, the reactants comprising HFH, catalyst, and methane; exposing the reactants in the reaction zone to microwave or RF energy, the exposing selectively converting at least a portion of the HFH to product, the product comprising paraffins and aromatics, wherein the ratio of paraffins to aromatics is greater than 0.05:1; and recovering at least the paraffins from the reaction zone.
12: The method of claim 11 wherein the product comprises gaseous, liquid flowable, and non-flowable materials, and wherein the method further comprises separating at least one of the gaseous, liquid flowable, and non-flowable materials from the product of the reaction zone.
13: The method of claim 12 wherein the liquid flowable material comprises paraffins.
14: The method of claim 12 wherein the liquid flowable material comprises alkylated aromatics.
15: The method of claim 12 wherein the liquid flowable material comprises both alkylated aromatics and paraffins.
16: The method of claim 12 wherein the gaseous material comprises single ring aromatics.
17: A heavy fossil hydrocarbon (HFH) reaction product comprising paraffins in substantially higher concentration than single ring aromatics, the product prepared according to the following process: providing reactants to a reaction zone, the reactants comprising HFH, catalyst, and methane; and exposing the reactants in the reaction zone to microwave or RF energy, the exposing selectively converting at least a portion of the HFH to the product comprising paraffins in substantially higher concentration than single ring aromatics.
18: The HFH reaction product of claim 17, wherein the reaction zone comprises one or more of a fluidized bed reactor, an entrained flow reactor, a free fall reactor, an ebulating bed reactor, and/or a moving bed reactor.
19: The HFH reaction product of claim 17, wherein the catalyst comprises one or more of nickel, cobalt, molybdenum, carbon, copper, alumina, silica, and/or oxygen.
20: The HFH reaction product of claim 17, wherein the catalyst and the HFH are admixed.
21: The HFH reaction product of claim 17, further comprising a plasma in or near the reaction zone.
22: The HFH reaction product of claim 17, wherein the catalyst has a concentration between 0.5 and 10 wt % relative to the HFH.
Description
DESCRIPTION OF DRAWINGS
[0018] Embodiments of the invention are described below with reference to the following accompanying drawings,
[0019]
[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
DETAILED DESCRIPTION
[0027] The following description includes the preferred best mode of one embodiment of the present invention. It will be clear from this description of the invention that the invention is not limited to these illustrated embodiments but that the invention also includes a variety of modifications and embodiments thereto. Therefore the present description should be seen as illustrative and not limiting. While the invention is susceptible of various modifications and alternative constructions, it should be understood that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.
[0028] Flash-heating and/or quenching of products can prevent retrogressive reactions typically associated with conventional HFH conversion, while selectively heating only the HFH can reduce process and thermal inefficiencies. Embodiments of the present invention utilize selective flash-heating of the HFH and/or HFHTL catalyst while keeping the bulk media at temperatures below pyrolytic conditions, thus effectively quenching the volatilized products or oils by the cooler bulk media. The selective flash heating can be accomplished through dielectric discharges created by uneven charge build up between or within HFH and/or catalyst particles, introducing the HFH and/or catalyst into a plasma, or rapid heating as a result of introducing microwave and/or RF irradiation.
[0029] Embodiments described in this document encompass adsorption of radio frequency (RE) or microwave energy at a frequency in which heating of moisture is not the primary mode of heating or absorption of RF or microwave energy. Rather, heating and absorption of the RF or microwave energy can be achieved through semiconductor materials, which can include a hybrid HFHTL catalyst impregnated within the HFH or the HFH itself, until dielectric collapse occurs within and/or between the HFH, the catalyst particles, and/or the reactor components (e.g., reactor walls, wave-guide components, or conductive or semiconductor materials placed within the reactor) due to non-uniform charge build up on the HFH particles, catalysts, and/or reactor components. In some instances, the dielectric collapse can result in plasma discharge. Within each discharge, temperatures within the immediate region of the discharge can approach and even exceed 1500 C., but are typically quenched by the surroundings within microseconds. Regardless of the temperature in and near the discharge, there is minimal change to the bulk temperature in the reactor and/or reaction zone. As a result of the discharge, dramatic cleavage and rearrangement of organic structure can occur at the spark discharge source particle and the immediate surroundings (ca. 0.1 cm). Any products and volatile matter are then released from the HFH into the surrounding media, which remains relatively cool. A plasma created locally in the immediate region of a particle or preformed in the reaction zone generates reactive ion species (e.g. H, C, CH.sub.x, Ar, O, or N ions) that can readily interact directly with the HFH, with the released products and volatile matter, or with other reactive ions that can act as a catalytic initiator for the decomposition, hydrogenation, dehydrogenation, and other reactions that converts the HFH and/or reactive gas into different species.
[0030] By avoiding excessive heating of the bulk media, retrogressive and decomposition reactions can be reduced, which can improve liquid yields by extreme flash conversion and/or conversion. With RF or microwave induced conversion, thermal energy (e.g., from a combustion source) is minimized or eliminated and the energy that is required for liquefaction is concentrated and/or targeted within the reaction zone, instead of across the entire reactor and its contents as with a conventional thermal flash pyrolyzer, which has relatively high thermal inefficiencies.
[0031] The following tables and figures demonstrate and describe a variety of aspects and embodiments and were obtained using a high volatile bituminous Pitt #8 coal as a representative HFH. Unless specified otherwise the coal was used as received without drying or demineralization. The size of the coal was reduced to 60 mesh (<0.25 mm). To avoid plugging issues, the particle size range of the coal was narrowed to 100-200 mesh (74-149 micron) for most of the examples described herein. Proximate and Ultimate analysis of the Pittsburgh seam coal used as a representative HFH is shown in Table 1 and Table 2, respectively.
TABLE-US-00001 TABLE 1 Proximate Analysis of Pitt #8 Coal (DECS-23) Proximate Analysis as rec'd dry daf dmmf (Parr) % Moisture 2.00 % Ash 9.25 9.44 % Vol. Matter 38.63 39.42 43.53 42.33 % Fixed Carbon 50.12 51.14 56.47 57.67 2.5% equilibrium moisture
TABLE-US-00002 TABLE 2 Ultimate Analysis of Pitt #8 Coal (DECS-23) Ultimate Analysis as rec'd dry daf dmmf (Parr) % Ash 9.25 9.44 (12.32% MM) % Carbon 72.72 74.21 81.95 84.64 % Hydrogen 5.00 5.10 5.63 5.82 % Nitrogen 1.32 1.35 1.49 1.54 % Total Sulfur 3.79 3.87 4.27 % Oxygen (diff) 5.91 6.03 6.66 8.00
[0032] Referring first to
[0033] 1-2 grams of coal (<60 mesh, as reed) were inserted between two quartz wool plugs within a 10.5 mm ID (12.5 mm OD) quartz reactor tube. Three Ni-chrome alloy wires of 40 mm in length were tightly intertwined together to form a single rope of 25 mm in length, with three spokes on the top and bottom of the wire rope. The wire elements were typically inserted into the reactor tube prior to loading of the coal around the wires, and served as a microwave antenna to direct the microwave energy to the coal bed and to aid in the ignition of dielectric discharges throughout the coal bed. The reactor tube was then placed in a larger 0.75OD (0.625ID) quartz outer tube and the top and bottom of the reactor tube were sealed within the larger outer tube with Teflon gaskets (outside the oven cavity). This enabled rapid reactor turnaround and more accurate mass balance calculations through weighing and loading of the inner tube.
[0034] Gas was introduced at a flow rate of 200 sccm (total) through the outer quartz tube using mass flow controllers. The Teflon seals placed around the reactor tube force the gas through the static coal bed. The microwave time for the experiments varied between 30 seconds and 10 minutes. Products were collected in a series of cold traps, the first being chilled to 0 C. and the second trap was chilled with dry-ice and propanol to a temperature of 78 C. The gas was then passed through an online-gas GC and then collected in a gas sample bag for further analysis and quantification of the gas formed/consumed during microwave conversion.
[0035] Baseline tetrahydrofuran (THF) extractions of as received Pitt #8 (DECS-23) coal in the batch reactor are shown in Table 3. The THF extractions were performed to assess the amount of extractable product without microwave or thermal treatments for direct comparison of the improvement in soluble products with application of various conversion energies. Extractions of Pitt#8 with THF yielded between 13 and 16 wt % THF soluble tars; with little to no pentane soluble oil yield.
TABLE-US-00003 TABLE 3 Baseline THF Extractable Yields from Pitt #8 (as rec') Wt THF Wt 1st THF Wt 2nd THF Mass Initial Wt Insoluble Extractables Extractables Wt % THF Balance Coal (g) (g) (g) (g) Solubles (%) Pitt #8 2.1499 1.9881 0.2546 0.0228 13% 105% Pitt #8 2.1958 1.9859 0.2272 0.1139 16% 102%
[0036] Baseline thermal yields of Pitt#8 coal at 350 C. were performed at elevated pressures of inert and hydrogen gases, and the results are presented in Table 4. 350 C. was selected as the conversion temperature to determine if any pyrolytic or devolatilization reactions would occur during char-vapor separations within heated cyclones during experimental trials. As shown in Table 4, the effect of a conversion temperature of 350 C. had little influence on the net conversion of coal and the THF soluble tar yield was similar to the baseline THF extractable yields from Pitt#8. The effect of gas headspace of either nitrogen or hydrogen also showed little impact.
TABLE-US-00004 TABLE 4 Baseline Thermal Conversion Yields of Pitt#8 Coal at 350 C. under 450 psi N.sub.2 and THF Insolubles Gas Yield THF Soluble Tar Mass Coal Wt % Wt % Wt % Balance Coal Pyrolysis Conditions loading Wt (g) (as recv'd) Wt (g) (as recv'd) Wt (g) (as recv'd) (%) Pitt #8 350 C., 1 hr, 450 psi N.sub.2 1.01 0.836 82.77 0.0217 2.15 0.131 12.97 98.9% Pitt #8 350 C., 1 hr, 450 psi H.sub.2 1.00 0.818 81.8 0.0298 2.98 0.146 14.6 99.4%
[0037] Initial coal conversion experiments were performed with various coal-to-liquids (CTL) catalysts within a static coal bed under flowing nitrogen gas in a quartz tube that is placed through an off-the-shelf home microwave oven. With no catalyst, little to no coal conversion was observed at microwave exposure times of 5 minutes, as shown in Table 5. Doping the coal with 2-10 wt % of CTL catalysts (ferrihydrite and magnetite) and iron filings (40 mesh) also showed little to no effect on coal conversion and bed temperatures never exceeded 200 C. This indicated that poor MW energy transfer to the coal bed and/or the CTL catalysts and metal flakes were ineffective for facilitating MW heating or plasma discharges. Only in the case of experiment MWPy009 was any significant conversion of coal observed. This was also the only run in which dielectric discharges were observed, indicating that without the presence of dielectric discharges or a plasma the coal will not undergo any significant conversion.
TABLE-US-00005 TABLE 5 Product Yields from Initial MW Conversion Experiments MW time Coal Gas Yield Solid Yield Gas + Extract Yield Run ID: Coal Catalyst (min) Load (g) wt wt % wt wt % wt wt % extraction Pitt none 0 2.15 0 0 1.99 92.5% 0.162 7.5% MWPy007 Pitt none 5 1.5 0 0.0% 1.39 92.7% 0.11 7.3% MWPy008 Pitt 20 wt % Fe-Filings 5 1.2 0 0.0% 1.04 86.7% 0.16 13.3% MWPy009 Pitt SS wire 5 1.5 0.15 10.1% 0.80 53.3% 0.70 46.7%
TABLE-US-00006 TABLE 6 An incomplete list of appropriate catalysts with summarizations of the performance and certain characteristics of each catalyst. Class Material (size) Discharge Characteristics Catalytic Potential CTL Fe-filings (420 micron) Intermittent discharging with blue plasma- modest hydrogenation activity (CH4), Catalysts induced glow, some heating highest BTX yield Fe-powder (~100 micron) Dramatic discharging for entire 30 second not tested in static system, evaluating in duration, sample fused continous system - potential to improve discharge w/smaller particles FeCS (nanocatalyst) No response Highest hydrogenolysis and deoxygenation activity under hydrogen flow Fe-ferrihydrite (nanocatalyst) No response good deoxygenation activity, modest hydrogenolysis activity FeS-JL (nanocatalyst) No response Highest oil yield w/methane feed (28 wt %), highest selectivity to JP-8 intermediates (-ring aromatics) Methane NiO (150-250 micron) No response low catalytic potential Conversion NiO-Reduced in H2 (150-250 Dramatic discharging, highest intensity and high potential CH4 conversion; but or Upgrading micron) duration requires catalyst pretreatment and Catalysts recovery G-90: Promoted NiO/Al2O3 (150- No response commercial methane reforming catalyst - 500 micron) low catalyst potential G-90: Promoted NiO/Al2O3 (<88 No response commercial methane reforming catalyst - micron) low catalyst potential USY (<150 micron) No response potential insitu upgrading - no discharge activity USY (.854-2 mm) No response potential insitu upgrading - no discharge activity Possible Amorphous Carbon (<150 micron) No response none Diluent or Amorphous Carbon (420-841 Some sparking, plasma formation possible indication of improved discharge Fluidization micron) w/larger coal particles Materials Char (<250 micron) Dramatic discharging, intermediate duration Ideal diluent material to prevent caking and improve discharges/plasma stability Graphite (fines) Strong-localized discharges, highest heat Indication of desired char properties generation alpha-Alumina (~150 micron) No response none Silicon carbide (23 micron) No response none Silicon carbide (100 micron) No response none Silicon carbide (150 micron) No response none HS-5 Silica (fumed silica) No response none - current diluent to avoid caking
[0038] Table 6 contains a summary of the performance and characteristics of a variety of catalysts, including those that exhibit dielectric discharge, hydrogen formation, and/or dilution characteristics. As described elsewhere herein, initiation of dielectric discharge is a critical function of suitable catalysts according to embodiments of the present invention. In addition to those shown in Table 6, rapid heating and ignition of dielectric discharges were observed for copper wire, magnetite, and iron filings in argon and air flows.
[0039] Dielectric discharge was observed from iron filings in separate experiments, even though no appreciable coal conversion or dielectric discharges were observed for the coal with Fe-filings in experiment MWPy008. A potential cause for this discrepancy is poor energy absorption. The lack of coal heating or dielectric discharges was hypothesized to be related to the distribution of the electromagnetic energy fields within the reactor's MW oven cavity. Accordingly, in some embodiments, stainless steel wires can be inserted around the coal bed to enhance energy conversion at and around the coal bed. After inserting the metal wires, a successful plasma ignition between the wires was observed and plasma-induced coal conversion was successful, as shown for experiment MWPy009 in Table 5.
[0040] In addition, the catalytic materials tested in Table 6 were re-evaluated for the potential ability to catalyze dielectric discharges and/or plasma formation when physically mixed with amorphous carbon. In all cases when the materials were packed in a manner in which there was a continuous bed of solids where all particles were touching, no dielectric discharges or plasmas were observed. However, when the materials were dispersed slightly, dramatic discharges were observed indicating that the use of any material that promotes dielectric discharges or plasmas can be used in the continuous flow process to enable plasma and dielectric discharge generation at pressures greater than 0.9 atm, thus enabling plasma and dielectric discharge conversion of coal and other HFH to occur at pressures outside the traditional envelope of high-vacuum plasma applications.
[0041] Conversion product yields from Pitt#8 coal in nitrogen flow were 10.1 wt % (as recd) gas, 36.6 wt % (as recd) THF soluble products, and 53.3 wt % (as reed) char. The composition of the gas recovered from the MWPy009 experiment is presented in Table 7. The total recovered tar/oil extracts (47.9 wt %) contained 33 wt % (as received) pentane soluble oil product, which would be considered material that can be upgraded to a JP-8 fuel.
TABLE-US-00007 TABLE 7 Summary of the composition of the gas recovered from conversion of MWPy009. Gas Mole (%) Gas Mole (%) N2 73.9 Ethane 0.97 O2 1.0 Ethylene 1.3 H2 11.5 CO 2.8 CH4 7.8 CO2 0.63
[0042] Table 8 shows the products and repeatability of MW-induced conversion within the static coal reactor when stainless steel wires are inserted into the static coal bed. For each experiment nitrogen sweep gas was continuously passed over the coal bed. The gas composition for MWPy011 and MWPy012 is shown in Table 9. A significant amount of hydrogen gas is directly generated from the coal during MW-induced conversion, and the majority of the carbon-containing species were methane, ethane and ethylene with some CO and CO.sub.2 formation due to liberation of oxygen from the coal.
TABLE-US-00008 TABLE 8 Product Distribution and Repeatability of MW-Induced Coal Conversion with Stainless Steel Wires Inserted into a Static Coal Bed under Nitrogen Flow MW Coal Pentane Total Tar Yield time Load Char Yield Gas Yield Insol. Pentane Sol. (THF Sol) Mass Run ID: Coal Catalyst (min) (g) wt (g) wt % wt (g) wt % wt (g) wt % wt (g) wt % wt (g) wt % Balance MWPy011 Pitt steel wires 5 2.03 1.19 58.6% 0.285 14% 0.032 1.6% 0.53 26.0% 0.56 27.6% 100.2% MWPy012 Pitt steel wires 5 2.02 1.001 49.6% 0.131 6% 0.035 1.7% 0.70 34.7% 0.74 36.4% 92.4%
TABLE-US-00009 TABLE 9 Gas compositions resulting from the MW-induced conversion of Pitt#8. Composition mole % Gas MWPy011 MWPy012 H2 16.76 7.173 CO2 0.373 0.322 ethylene 0.905 0.545 ethane 0.337 0.523 AR/O2 1.321 N2 71.089 85.639 CH4 6.913 4.552 CO 2.302 1.246
[0043] The pentane soluble fraction's composition was analyzed by GCMS and is presented in
[0044] To improve the hydrogen content of the products of MW-induced conversion hydrogen and/or methane gas was used as a hydrogen source. Table 10. Effect of Nitrogen and Hydrogen Sweep Gas on Product Yields during Static MW shows the effect of 90% hydrogen gas in 10% nitrogen as a sweep gas during static microwave-conversion of Pitt#8 coal without a catalyst. Introduction of hydrogen to the system reduced the overall liquid and gas product yield and resulted in plugging of the reactor tube within 6 minutes. Furthermore the mass balance was reduced, which through later experimentation was shown to be a result of loss of lighter hydrocarbons and BTX components during solvent removal. Although the yields were reduced there was a reduction in the phenols, cresols, and xylenols (PCX) content of the collected liquid products (as shown in
TABLE-US-00010 TABLE 10 Effect of Nitrogen and Hydrogen Sweep Gas on Product Yields during Static MW Conversion MW Coal Pentane Pentane Total Tar (THF Purge time Load Char Yield Gas Yield Insolubles Solubles Sol) Mass Run ID Gas Catalyst (min) (g) wt (g) wt (%) wt (g) wt (%) wt (g) wt (%) wt (g) (%) wt (g) wt (%) Balance MWPy017 N2 none 7 2.02 1.060 52.5% 0.179 8.9% 0.1 5.0% 0.29 14.4% 0.39 19.3% 80.6% MWPy018 90% H2 none 6 2.08 1.217 58.5% 0.1083 5.2% 0.062 3.0% 0.16 7.7% 0.222 10.7% 74.4%
[0045] Table 11. Effect of N2, H2, and CH4 Sweep Gas on Product Yields during MW shows the products formed during microwave-induced conversion of a static Pitt#8 coal bed as a function of sweep gas used. For all tests the microwave heating time was 5 minutes, a total gas flow rate of 200 sccm, and 2 g of coal was used. Under similar conditions as before (MWPy-011 and MWPy-012), the result of using a the modified microwave oven system (i.e., lower power microwave source and addition of a water dummy load) reduced the overall product yield for experiment MWPy038.
TABLE-US-00011 TABLE 11 Effect of N.sub.2, H.sub.2, and CH.sub.4 Sweep Gas on Product Yields during MW Conversion net gas Oil Yield Pentane Tar Yield Sweep formed CHAR (pentane sol.) Insoluble Oil (THF Sol.) mass Run ID Gas Catalyst wt (g) wt % wt (g) wt % wt (g) wt % wt (g) wt % wt (g) wt % balance % MWPy038 N2 none 0.158 10.5 0.950 62.9 0.302 20.0 0.06 4.0 0.362 24.0 97.4% MWPy030 90% H2 none 0.035 2.1 1.360 83.4 0.088 5.4 0.13 8.0 0.218 13.4 98.9% MWPy035 90% CH4 none 0.061 4.1 0.860 57.3 0.274 18.3 0.14 9.3 0.414 27.6 89.0%
[0046] Referring to
[0047]
[0048] In at least the reaction zone, the HFH and HFHTL catalyst are contacted 505. Microwave or RF energy is emitted 502 into the reaction zone from a source. Dielectric discharging 506 occurs in at least the reaction zone to promote conversion of the HFH. Products and waste flow out 503 of the reaction zone. The HFH and HFHTL catalyst have a residence time of less than 30 seconds in the reaction zone.
[0049] Table 12 summarizes the product yields from microwave conversion of Pitt #8 coal under various conditions in a continuous flow-reactor such as the one depicted by
[0050] During plasma conversion the reactive plasma ions can react directly with the coal or HFH to form acetylene that then polymerizes to yield benzene, styrene, and other polymeric products. The increased BTX compounds can be a result of plasma-induced ring-opening reactions of hydroaromatics, which are formed during catalytic hydrogenation of naphthalenes and other polyaromatic species, followed by side-chain cleavage. The intensity of the plasma and the relative concentration of the reactive plasma ions can be controlled to maximize the yield of distillates and/or to minimize acetylene formation and over-cracking of the evolved oils.
TABLE-US-00012 TABLE 12 Product Yields from Continuous Microwave Conversion of Pitt Coal Total wt Coal wt % Char Tar Yield total Oil Total Liquid Yield Total Mass Feed (g) Fed (daf) (wt %) (wt %, daf) (wt %, daf) Balance MWPy-116, N2/no-cat 4 2.8 58.4 2.0 19.7 21.7 84.4 MWPy-120, H2/no cat 4 2.9 58.4 2.7 20.6 23.3 85.6 MWPy-126, 25% H2/Fe Powder/1000 W 15 11.6 18.8 3.0 41.9 44.9 71.6 MWPy-134, 25% H2/Fe Powder/600 W 18 13.8 26.9 9.1 33.1 42.2 75.8 MWPy-142, 10% H2/Fe Powder/600 W 4 2.9 35.6 2.1 30.9 33.0 75.5
TABLE-US-00013 TABLE 13 Conversion of Pitt Coal to Hydrocarbons below the JP-8 Boiling Range Light Ends (wt %, daf) MWPy-126, 25% H2/Fe Powder/1000 W 13.86 MWPy-134, 25% H2/Fe Powder/600 W 5.61 MWPy-142, 10% H2/Fe Powder/600 W 0.54
[0051] In some embodiments, methane and HFH such as coal can be co-pyrolyzed. Methane conversion can lead to extensive carbon coating of the reactor walls. In one particular instance, an argon plasma can be pre-formed within the microwave zone to reduce the detrimental carbon build up. An inner feed tube supplying methane and coal was lowered to a position near the exit of the waveguide, thus preventing methane or coal conversion within the microwave zone. In the instant configuration, the coal and methane were introduced into the pre-formed Ar plasma and only in lower sections of the reactor was a methane/coal/Ar plasma observed. While carbon buildup was reduced within the microwave waveguide, the observed oil yields were relatively low, as shown in Table 14 Product Yields from Co-Conversion of Methane and Coal in a Microwave Plasma. Without the addition of hydrogen to the feed, the oil yield was only 14.8 wt % (total tar 26.6 wt %). Addition of a small amount of hydrogen increased the oil yield to 22.3 wt % but the total tar yield remained low at 24.5 wt %. Accordingly, in some embodiments, hydrogen can be introduced to aid in the conversion of asphaltenes to soluble oils without influencing the deconstruction of the coal into oils but rather promoting the formation of acetylene and gaseous hydrocarbons from methane and coal. Under the same conditions (1 atm pressure, no preheating, 18% CH4/1.5% H.sub.2 in Ar process gas, and coal feed rate of 5 g/hr) the addition of a hydrotreating catalyst (CoMo/Al2O3) can improve the oil and tar yields to 29.7 and 38 wt %, respectively. During these tests the coal itself was not generating rapid dielectric discharges, which is likely due to little to no exposure to microwave irradiation prior to entering the preformed plasma.
TABLE-US-00014 TABLE 14 Product Yields from Co-Conversion of Methane and Coal in a Microwave Plasma Total Overall Char Yield Char Yield Tar Yield Oil Yield (wt % total Liquid Net Gas Mass (wt % daf) (wt % daf) (wt % daf) daf) Yield (wt % daf) Yield (wt %) Balance (%) MWPy-169, 5% Fe Catalyst, 85.63 64.05 11.79 14.80 26.59 5.51 92.82 6% CH4 in Ar MWPy-201, 5% Fe Catalyst, 73.61 55.72 2.26 22.32 24.58 0.67 99.26 18% CH4/1.5% H2 in Ar MWPy-203, 5% Fe Catalyst + 68.88 32.82 8.28 29.72 38.01 2.61 97.22 5% Hydrotreating Catalyst, 18% CH4/1.5% H2 in Ar
[0052] To enhance dielectric discharges between coal particles, the reactor can be further modified to increase the exposure of coal to microwave energy by increasing the outer Ar sheath gas flow to avoid carbon coating on the wall of the reactor and/or by employing a modified flow distributor disk having a structure that resulted in higher gas velocity along the walls of the reactor. This enabled the inner feed tube to be raised above the main reaction zone, thus increasing the exposure time of the entrained coal to microwave irradiation. Alternative designs can be considered as part of the current embodiment that can include alternative methods to introduce coal, HFH, gases, and microwave/RF energies.
[0053] In some embodiments, the coal feed rate is greater than 5 g/hr. For example, increasing the coal feed rate from 5 g/hr to 30 g/hr dramatically improved dielectric discharging between coal particles, likely due to increased proximity and uneven charging of coal particles enabling corona discharging between particles. As a result of higher coal feed rates, the gas flow also can be increased from 4 L/min to 12 L/min to avoid reactor plugging due to coal swelling, which further improved dielectric discharges between coal particles. The increased flow rates results in a reduction of the residence time in the microwave zone from 126 to 75 msec. Increasing the coal feed-rate, from 5 to 30 g/hr, significantly increased the observation of dielectric discharging between coal particles (run MWPy-215 in Table 15 Product Yields from Co-Conversion of Methane, Hydrogen, and Coal in a Microwave Plasma). This increase in the dielectric discharging between coal particles resulted in a significant increase in oil yield to 35 wt % (daf), despite the reduced residence time. This indicates that operational parameters such as coal (or HFH) particle proximity, concentration, exposure time to microwave/RF irradiation, reactor configurations, wt % coal feed in the process gas, relative plasma position and energy density, and net residence time can all be adjusted and controlled to improve reactor performance, alter product distributions, increase product yields and reduce operational costs. Unlike the static bed tests, an entrained or fluidized coal bed can significantly enhance yields and performance by distributing the coal, catalyst, or dilution media within the process gas allowing for uneven electric charge buildup, whereas when particles are in direct contact the ability to generate uneven charge build up between particles is limited, thus reducing the degree of dielectric discharging between entrained particles.
TABLE-US-00015 TABLE 15 Product Yields from Co-Conversion of Methane, Hydrogen, and Coal in a Microwave Plasma Char Tar Yield Yield Total Oil Total Liquid Net Gas BTX/Light Mass CH4 H2 (wt % (wt % Yield Yield Yield HC Yield Balance Conversion Conversion daf) daf) (wt % daf) (wt % daf) (wt %) (wt %, daf) (%) (%) (%) MWPy-211, 5% Fe Catalyst, 59.70 0.85 24.36 25.23 7.47 10.86 96.61 3.90 7.88 39:8:53 Coal:H2:CH4 (wt ratio) - 700 W MWPy-215, 5% Fe Catalyst, 45.60 7.13 34.87 41.99 0.46 17.85 89.17 11.25 17.30 43:6:51 Coal:H2:CH4 (wt ratio) - 700 W MWPy-219, 5% Fe Catalyst, 37.40 3.71 58.49 62.19 1.90 23.98 98.90 n.a. 9.37 79:21 Coal:H2 (wt ratio) - 700 W
[0054] In some embodiments, hydrogen and coal are co-fed. To compare directly the effect of co-feeding methane versus co-feeding hydrogen, experiment MWPy-219 was performed and the results are shown in Table 15 Product Yields from Co-Conversion of Methane, Hydrogen, and Coal in a Microwave Plasma. By co-feeding hydrogen rather than methane during conversion significantly increased the oil yield to 58.5 wt % (daf) and the overall liquid yield was 62 wt % (daf). This increase is directly related to the need for increasing the plasma energy-density required for sufficient methane conversion during plasma conversion. During tests without co-feed of coal, methane conversions as high as 75% per pass were observed and when coal is co-fed the methane conversion observed is 4-11%. This is due to the need for methane to be exposed to a plasma having relatively higher energy density, which can be efficiently and readily generated in a plasma torch. If coal is pyrolyzed in a plasma torch reactor (or similarly a thermal plasma), the main product of coal conversion is acetylene and acetylene polymers and conversion is limited by mass transfer of the ions within the plasma to the surface of the coal. Testing performed indicates that a yield of oil under such operation leads to 20-25 wt % (daf) and the product selectivity is 80-85% BTX with only minimal conversion to distillate fuel boiling range compounds. However, by relatively increasing the intensity and occurrences of dielectric discharges the oil yield can be improved, but the lower-energy plasma is not sufficient for high methane conversions. Preferably, a natural gas conversion unit is segregated and hydrogen, rather than methane, is co-fed with the coal. In such instances, an oil yield of 58.5 wt % has been demonstrated. Due to the differences in the mode of operation required for optimal methane conversions and high oil yields from coal, preferred embodiments segregate the two processes and use RF or barrier discharge reactors for methane conversion and continue to use microwave energy for conversion of coal entrained in hydrogen (and other product gases from methane conversion).
[0055] Alternative catalytic materials can be used to help lower the energy requirements associated with co-feeding methane and coal, while improving overall methane conversions. An example of including a reduced nickel catalyst into the reaction zone is illustrated in Table 16 where NiSAT catalyst (commercial Nickel-based catalyst Sud-Chemie) was added to the coal feed mix. In this particular example when hydrogen was co-fed with the coal the overall liquid yield was 46.16 wt %, indicating the Ni is also aiding in increasing the hydrogen transfer reaction thus increasing the oil yield when compared to the case without Ni catalyst. When methane is co-fed with the hydrogen and coal (with the Ni catalyst) the liquid yield further increased to 62 wt % and 34% of the methane was converted into other products, including hydrogen as indicated by the negative hydrogen conversion number (indicates more hydrogen is exiting the reactor than entering the reactor). This demonstrates one method in which energy required for methane decomposition can be lowered by variations in catalytic materials that can help promote hydrogenation, methane decomposition, and hydrogen formation.
TABLE-US-00016 TABLE 16 Summary of results when NiSAT catalyst is added to the coal feed mix for microwave conversion Char Total Yield Total Oil Liquid Net Gas BTX/Light Mass CH4 H2 (wt % Tar Yield Yield Yield Yield HC Yield Balance Conversion Conversion daf) (wt % daf) (wt % daf) (wt % daf) (wt %) (wt %, daf) (%) (%) (%) MWPy-263: Pitt#8 + 5% 50.07 5.67 40.49 46.16 5.84 18.70 100.2 n.a. 16.94 FE Catalyst + 5% NISAT 6:1 Coal:H2, 29.4 g/hr coal feed rate 700 W microwave power 600 W Acoustic MWPy-265: Pitt#8 + 5% 55.43 8.80 53.32 62.12 16.14 17.06 99.71 34.18 9.70 FE Catalyst + 5% NISAT 8:1:8 Coal:H2:CH4, 29.7 g/hr coal feed rate 700 W microwave power 600 W Acoustic
[0056] Referring next to
[0057] Reaction zone 604 can be a reactor as described in the present disclosure, and this reactor can utilize microwave and/or radio frequency energy. Upon providing HFH 602 to reaction zone 604, a heavy fossil hydrocarbon reaction product 606 may be created and/or obtained from reaction zone 604. In accordance with at least one example implementation, system 600 can be utilized to provide reactants to reaction zone 604, with the reactants including HFH, catalyst and methane, for example. The reactants can be exposed to microwave or RF energy within reaction zone 604, and the exposing can selectively convert at least a portion of the HFH to product 606. Product 606 can include paraffins, for example, and the paraffins can include straight chain or branched-chain hydrocarbons.
[0058] In accordance with an example implementation, a method for selectively preparing paraffins utilizing system 600 can be performed wherein the exposing the reactants in the reactive zone to microwave RF energy selectively converts the HFH to paraffins rather than aromatic hydrocarbons. The paraffins can be a product of ring opening reactions of poly aromatics either formed from the coal or formed as a secondary product. The paraffins may have some branching associated with them, for example a mix of normal and iso paraffins. The paraffins may also be cyclic or partially cyclic, for example a mixture of cycloparaffin and alkyl-cycloparaffins. In accordance with example implementations, the ratio of paraffins to aromatics can be at least 0.05:1. This ratio can be determined using gas chromatgraphy techniques, particularly GC/MS and integration of the area percents of peaks determined to be paraffins and aromatics. In accordance with example implementations, the paraffins may be prepared from the aromatics, or initial products from HFH conversion, and/or olefins of the HFH as well. As part of this reaction, for example, at least some of the HFH may be reacted to form aromatics and/or olefins. These aromatics and/or olefins may be then alkylated to form alkylated aromatics, straight chain, and/or branched chained hydrocarbons.
[0059] In accordance with additional methods that can utilize system 600, for example, methods for converting aromatic hydrocarbons of heavy fossil fuel to methylated aromatic hydrocarbons or other alkylated aromatic hydrocarbons can be performed. These methods can include providing the reactants such as HFH to the reaction zone 604, with the reactants comprising HFH, catalyst, and/or methane, and the HFH including aromatic hydrocarbons. In accordance with example implementations, the exposing the reactants in the reaction zone to microwave or RF energy can form a product, and the exposing selectively converts at least a portion of the aromatic hydrocarbons of the HFH to alkylated aromatic hydrocarbons, such as methylated aromatic hydrocarbons.
[0060] In accordance with yet another embodiment of the disclosure, methods for selectively preparing paraffins from heavy fossil hydrocarbons can include exposing reactants such as HFH, catalyst, and/or methane in a reaction zone to microwave or RF energy with the exposing selectively converting at least a portion of the HFH to product that includes paraffins and aromatics. As an example, the reaction selectivity of paraffins rather than aromatics is demonstrated in Tables 17 and 18 below.
[0061] In accordance with yet another embodiment of the disclosure, heavy fossil hydrocarbon reaction products that include paraffins in substantially higher concentration than single ring aromatics are provided. These reaction products can be prepared by providing reactants to a reaction zone, with the reactants comprising HFH, catalyst, and methane and exposing the reactants in reaction zone 604 to microwave or RF energy, with the exposing selectively converting at least a portion of the HFH to a product that includes paraffins in substantially higher concentration than single ring aromatics. Still with reference to
[0062] As mentioned above, the HFH may be provided separately or in combination with a catalyst to reaction zone 604. The catalyst can include one or more of iron, char, and/or a promoter of a dielectric discharge. The catalyst can also include one or more of nickel, cobalt, molybdenum, carbon, copper, alumina, silica, and/or oxygen, for example, and as mentioned, one or more of these catalysts can be admixed with the HFH and then provided to reaction zone 604. For example, the catalyst can have a concentration from between 0.5 and 10 wt % relative to the HFH provided to reaction zone 604.
[0063] A pressure within reaction zone 604 can be maintained from between 0.9 atm and 7 atm, for example, and reactants may have residence time within reaction zone 604 of from 5 milliseconds and 30 seconds.
[0064] Referring again to
[0065] Referring next to Table 17, as can be seen in the first two columns, reactions 1 and 2 represented as R1 and R2 are compared with reactions 3 and 4, represented as R3 and R4. Both reaction parameters including the reactants such as HFH 602 as well as the parameters of reaction zone 604 are shown in Table 17. Also shown in Table 17 is the characteristics of the product 606 obtained utilizing these reaction parameters.
TABLE-US-00017 TABLE 17 HQ-R1 HQ-R2 HQ-R3 HQ-R4 Coal Feed (g/hr, a.r) 52.9 20.6 176.6 224.4 H.sub.2/Coal (wt/wt, a.r.) .105 .137 .027 .020 CH.sub.4/Coal (wt/wt, a.r.) 0 .411 .11 .09 Applied energy (Wh/g.sub.coal, a.r.) 14.2 36.5 5.1 4.0 Mass balance (wt %) 107 115 106 100 Liquid yield (wt %, daf) 66.3 61.4 54.4 70.2 Hydrogen conversion 4.9 21.0 18.0 16.1 Methane conversion n.a. 38.4 37.2 18.5
[0066] Referring next to
[0067] Referring again to
TABLE-US-00018 TABLE 18 API Gravity and .sup.13C-NMR Analysis of Oil (Pentane and Toluene Soluble) Generated by WL Processing of Illinois #6 with Hydrogen and the Effect of Process Tuning Product Quality Run ID ILL-R1 ILL-R2 ILL-R4 ILL-R5 Approx. API Gravityof Total 9.5 6.3 8.6 9.3 Liquids % C based on .sup.13C-NMR Aromatic Carbon 87.04 79.45 57.74 49.37 Bridgehead 8.27 6.08 4.29 4.25 Peripheral Unsubstituted 54.54 47.64 21.16 19.50 Aliphatic Carbon 12.96 20.55 39.79 49.38 Naphthenic Carbon 0.00 11.33 18.33 20.70 Paraffinic Carbon 12.96 9.15 16.87 26.19 Methine Carbon 0.36 1.34 3.38 4.79 Methylene Carbon 6.34 10.00 24.82 33.41 Methyl Carbon 6.22 9.20 7.88 9.11 Phenolic Carbon 3.46 3.27 3.21 2.73 Estimated barrels per ton of 4.7 3.2 3.1 4.3 daf coal
[0068] Referring next to
[0069] Referring next to Table 19, a demonstration of the relative proportions and selectivity to desirable paraffins and methylated poly-aromatics is shown. Accordingly, their relative degree of alkylation demonstrates that utilizing methane can increase the selectivity to paraffins in product 606 from 0.15 to 2.52 compared to all other hydrocarbon products increasing the relative degree of hydrogenation between hydrogen co-feed and methane co-feed from 0.08 to 0.41. Further, upon modifying the catalyst to an iron powder based catalyst, the relative degree of paraffin olefins can be increased to a ratio of 5.24 and hydrogenation can increase to 0.5 while alkylation can increase from 1.67 to 3.17. Finally, when increasing the feed rate, it can be seen that hydrogenation can increase from 0.5 to 0.98.
TABLE-US-00019 TABLE 19 Methane Methane Hydrogen Methane Co-Feed Co-Feed Ion Ratio Used for Co-Feed Co-Feed Catalyst Increased Comparison Baseline Baseline Modification Feedrate Relative Degree of (91 + 105 + 169 + 156 + 115 + 0.52 1.67 3.17 3.41 Alkylation 141 + 142):(78 + 128) Alkylbenzenes:Benzene (91 + 105):78 0.31 0.52 0.73 0.77 Alkylnaphthalenes:Naphthalene (169 + 156 + 141 + 142):128 0.82 1.88 2.48 2.47 Realtive Degree of (132 + 131 + 138 + 145 + 146 + 0.08 0.41 0.50 0.98 Hydrogenation 160):(128 + 142 + 141) Tetralin&Decalin:naphthalene (132 + 138):128 0.08 0.29 0.32 0.33 C1&C2-tetralins:C1&C2- (145 + 146 + 160):(142 + 141) 0.18 1.42 1.74 5.24 naphthalenes Relative Degree of (55 + 57):total 0.15 2.52 5.24 4.73 Paraffins and Olefins Relative Ratio of (55 + 57):78 0.316 2.88 11.03 9.3 Paraffins/Olefins to Benzene Relative Ratio of (55 + 57):(78 + 91 + 105) 0.217 1.38 2.98 2.19 Paraffins/Olefins to Monoaromatic Relative increases Alkylation 1 3.2 6.1 6.6 Hydrogenation 1 5.5 6.6 13.0 Paraffin/Olefins 1 16.8 34.9 31.5 paraffin/olefin to benzene 1 9.1 34.9 29.4 paraffin/olefin to 1 6.4 13.7 10.1 Benzene/toluene
[0070] The systems and methods of the present disclosure can be utilized to prepare a product that can be actively separated, with reference to
[0071] In accordance with example implementations, methods utilizing the systems above can be utilized to recover at least paraffins from the reaction zone, and these paraffins are shown in the above figures and tables. In accordance with other methods, the products can be separated utilizing the separation zone to provide methylated aromatic hydrocarbons such as those methylated aromatic hydrocarbons depicted in
[0072] The method can include separating at least one of the gaseous, liquid, flowable, and/or non-flowable materials from the product of the reaction zone. According to example implementations, the liquid flowable material can include paraffins and the liquid flowable material may also include methylated or alkylated aromatics. In accordance with example implementations, the gaseous portion 614 may include single ring aromatics such as toluene and/or benzene, for example. In accordance with example implementations, the present disclosure can be utilized to react HFH in a way that simplifies product separation and also enhances more desirable products than previously disclosed.
[0073] While a number of embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims, therefore, are intended to cover all such changes and modifications as they fall within the true spirit and scope of the invention.