WO2016004323A2

WO2016004323A2 - Laser based production of syngas from underground carbonaceous material

Info

Publication number: WO2016004323A2
Application number: PCT/US2015/039013
Authority: WO
Inventors: Charles Brown; William O'neill
Original assignee: Conway Energy, L.C.
Priority date: 2014-07-02
Filing date: 2015-07-02
Publication date: 2016-01-07
Also published as: WO2016004323A3

Abstract

The present invention relates to a method of producing syngas from an underground carbonaceous material, comprising the steps of providing an injection well into underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; producing syngas; and extracting the syngas through the production well.

Description

LASER BASED PRODUCTION OF SYNGAS FROM

UNDERGROUND CARBONACEOUS MATERIAL

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to a method of producing syngas from an underground carbonaceous material, comprising the steps of providing an injection well into underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; producing syngas; and extracting the syngas through the production well.

DESCRIPTION OF THE PRIOR ART

[0002] The growing energy demand of developed and developing countries finds the answer always in fossil fuels. The larger availability and lower cost of coal, in respect to other fossil fuels, make it the leading energy resource for electricity generation across the world. On the other hand, coal is a source of environmental concern, not only for its greenhouse impact in terms to C0₂. Moreover the health and safety impact of conventional coal extraction methods on workers and local environments is also a major consideration. For these reasons, clean coal technologies are becoming more attractive, a political necessity for many governments, and a remarkable opportunity to develop the next generation of 'coal mining' technologies. The aim of these new technology developments being to deliver high overall extraction efficiencies, careful emission control, improvements in the health and safety of those involved and the opportunity of breeding new life into existing coal industries. This renewed scientific and technological interest pushes the development of reliable extraction technologies into new domains, and to support existing coal industries through the design and optimization of next generation coal conversion processes. Coal conversion is a complex processes, which involve many interactions of chemical and physical phenomena. Coal pyrolysis is always the first step and plays a fundamental role. Coal rank and properties significantly influence heat and mass transfer as well as conversion rates. Therefore, times, yields, and pollutant emissions depend on the original source and the means of conversion. The key to understanding the phenomena occurring inside the process lies first in the characterization of the initial coal and then in describing the primary devolatilization phase and the released products.

[0003] It is well known that coal devolatilization is a process in which coal is transformed at elevated temperatures to produce gases, tar, and char. Functional groups of the original coal are mainly released as gases and can be reasonably predicted by first-order reaction models. Tar, defined as condensable species formed during coal devolatilization, is a major volatile product, up to 50% of coal weight for bituminous coals.

[0004] Coal, like all other sources of energy, has a number of environmental impacts, from both coal mining and coal use. Coal mining raises a number of environmental challenges, including soil erosion, dust, noise and water pollution, and impacts on local biodiversity. Steps are taken in modern coal mining operations to minimize these impacts although they are still of considerable concern and environmental reparations are costly. Continuous improvements in technology have dramatically reduced many of the environmental impacts traditionally associated with the use of coal in the vital electricity generation and steelmaking industries. Viable, highly effective technologies have been developed to tackle the release of pollutants - such as oxides of sulphur (SO_x) and nitrogen (NO_x) - and particulate and trace elements, such as mercury. More recently, greenhouse gas (GHG) emissions, including carbon dioxide (C0₂) and methane (CH₄) have become a concern because of their link to climate change.

[0005] It is clear that economics of adding new coal power capacity in the United States using existing technologies and mining practices has become increasingly difficult to justify, given rising prices, greater scrutiny of the health, climate and other environmental hazards associated with coal power, and the emergence of a collection of alternatives, mainly wind, solar, with the base— load provision being provided by newly available natural gas, and nuclear provision. Direct replacement of old, dirty coal plants with cleaner, cheaper, less risky alternatives would be a far better solution. Clean coal could indeed be part of the energy mix and could offer the potential

[0006] There are a number of alternative methods in development for the conversion of coal deposits into useful sources of energy and materials, such as the extraction of coal bed methane from virgin seams and abandoned mines. These do not require the physical extraction of the coal and therefore have the potential to form the base of a new coal economy.

[0007] One such method is Underground Coal Gasification (UCG), whereby unworked coal, i.e. coal still in the ground, is converted into a combustible gas which can be used for industrial heating, power generation or the manufacture of hydrogen, synthetic natural gas or diesel fuel. UCG technology allows countries that are endowed with coal to fully utilize their resource from otherwise unrecoverable coal deposits in an economically viable and environmentally safe way.

[0008] UCG uses a similar process to surface gasification, developed in the 19th Century for the production of 'Town-Gas'. The main difference between both gasification processes is that in UCG the cavity itself becomes the reactor so that the gasification of coal takes place underground instead of at the surface.

[0009] The basic UCG process involves drilling three wells into the coal, one for injection of the oxidants (water/air or water/oxygen mixtures), another well some distance away to bring the product gas to the surface, and one at the end of the seam that acts as an ignition well, through which an ignition source is provided, see, e.g., FIG. 1. The coal at the base of the first well is then heated to temperatures that would normally cause the coal to burn. However, through careful regulation of the oxidant flow, the coal does not burn but rather separates into syngas.

[0010] Various chemical reactions, temperatures, pressures, and gas compositions exist at different locations within a UCG gasifier. The gasification channel is normally divided into three zones: oxidization, reduction, and dry distillation and pyrolysis. In the oxidization zone, multiphase chemical reactions occur involving the oxygen in the gasification agents and the carbon in the coal. The highest temperatures in the gasifier occur in the oxidation zone, due to the large release of energy during the initial reactions. The following reactions occur in the oxidation zone:

C+0₂→C0₂ +393.8 kJ

2C+0₂→2CO +231.4 kJ

2CO+0₂→2C0₂ +571.2 kJ

[0011] In the reduction zone, the main reactions involve the reduction of H₂0(g) and C0₂ into H₂ and CO at high temperatures within the oxidation zone. The following endothermic reactions occur in the reduction zone:

C+C0₂→2CO -162.4 kJ

C+H₂0(g)→CO+H₂ -131.5 kJ

[0012] Under the catalytic action of coal ash and metallic oxides, a methanation reaction occurs:

C+2H₂→CH₄ +74.9 kJ

[0013] Following ignition and the delivery of feed gas (air or oxygen) and steam, syngas is then drawn out of the second well. Two different methods of UCG have evolved and are commercially available: vertical wells combined with methods for opening the pathway between the well; inseam boreholes using technology adapted from oil and gas production that can move; the injection point during the process; a number of issues remain to be resolved before wider deployment can be achieved; the main criteria used for the identifying the resource areas with potential for UCG can summarized as seam^'s of 5 m thickness or greater; seams at depths between 200 m and 600 m from the surface; greater than 100 m vertical separation from major aquifers; greater than 100m vertical separation from major overlying unconformities; less that 60% ash content; other factors that need to be considered are impermeable layers of strata surrounding the target coal seam; absence of any major faults in the area; low values for sulphur content and ash content; environmental and hydro geological conditions; licence conditions that might be imposed by Regulatory and Planning authorities.

[0014] For example, a conventional UCG process is depicted in FIG. 2. Here, the front is ignited at the root of the injection well. Combustion then occurs along to seam until it reaches the production well. The rate of propagation of the combustion front is determined by many factors, such as gas flow kinetics, and variations in temperature, spallation levels etc. The cavities are generally tear-drop shaped, and the passage to the production wells are narrowed and can be obstructed yielding low combustion levels and restricted outflow and yield of combustible products.

[0015] There are a number of risks associated with current UCG practices, namely: heavy faulting; overburden composition and potential leakage of produced gases/by products into aquifers; maintenance of the ignition reaction, i.e. ground water or flow instabilities quenching the reaction subsidence due to cavity collapse; seam thickness variability coal conditions inductive to lateral combustion and uncontrolled growth; emissions or migration of potentially harmful combustion products; potential for contamination.

[0016] There remain a number of technology challenges that must be addressed in order to improve current UCG process technologies.

SUMMARY OF THE INVENTION

[0017] It is an object of the present invention to obviate or mitigate at least one of the above- mentioned disadvantages of the prior art.

[0018] The present invention relates to a method of producing syngas from an underground carbonaceous material, comprising the steps of providing an injection well into underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; producing syngas; and extracting the syngas through the production well.

[0019] In some embodiments, the method further comprises providing one or more gases into the linkage bore including, but not limited to, oxygen, steam, air, or combinations thereof.

[0020] In some embodiments of the present invention, the laser heats the carbonaceous material only to a sufficient temperature to achieve ignition, thereby sustaining the production of syngas without the need of further heating by the laser.

[0021] In some embodiments the present invention is directed to a method of producing syngas from an underground carbonaceous material, comprising the steps of providing an injection well into an underground carbonaceous material, providing a production well into the underground carbonaceous material, providing a linkage bore in the underground carbonaceous material running from the injection well to the production well, providing a laser into the linkage bore, heating the carbonaceous material located in the linkage bore with the laser, producing a syngas, and extracting the syngas through the production well. In some embodiments, the method further comprises providing one or more gases into the linkage bore from the injection well. In some embodiments, the one or more gases comprises steam. In some embodiemtns, the method further comprises processing the syngas to remove impurities and carbon dioxide to provide a clean syngas; and using the clean syngas to generate power, produce fuel products, produce chemical products or combinations thereof. In some embodiments, the laser is a high-powered fiber laser capabale of delivering at least 20kW of power.

[0022] In some embodiments, the syngas is produced through a pyrolysis reaction. In some embodiments the pyrolysis reaction temperature is from 700 °C to 1200 °C. In some embodiments the syngas comprises from 1 percent to 10 percent by mole carbon dioxide. In some embodiments the syngas comprises from 1 percent to 10 percent by mole carbon monoxide. In some embodiments the syngas comprises from 20 percent to 30 percent by mole methane. In some embodiments the syngas comprises from 40 percent to 50 percent by mole hydrogen. In some embodiments the syngas comprises a mole ratio of hydrogen to carbon dioxide of about 15: 1. [0023] In some emboidments, the present invention is directed to a syngas composition prepared by a process comprising the steps of providing an injection well into an underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; and producing a syngas; wherein the syngas compises from 1 percent to 10 percent by mole carbon dioxide, from 1 percent to 10 percent by mole carbon monoxide, from 20 percent to 30 percent by mole methane, from 40 percent to 50 percent by mole hydrogen. In some embodiments, the syngas comprises a mole ratio of hydrogen to carbon dioxide of about 15:1.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:

Figure 1 illustrates a conventional UCG process.

Figure 2 illustrates a cavity produced in a conventional UCG process.

Figure 3 illustrates an embodiment of the present invention.

Figure 4 illustrates an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention relates to a method of producing syngas from an underground carbonaceous material, comprising the steps of providing an injection well into underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; producing syngas; and extracting the syngas through the production well.

[0026] As used herein, the term "carbonaceous material" refers to any solid, liquid or gaseous carbon-containing material suitable for use as a fuel, i.e. a material which can be consumed to produce energy. Included within the scope of this term are fossil fuels, including coal, oil, natural gas, and oil shale, biomass, i.e. plant materials and animal wastes used as fuel, coke, char, tars, wood waste, methanol, ethanol, propanol, propane, butane, ethane, etc.

[0027] As used herein, the term "laser" refers generally to a category of optical devices that emit a spatially and temporally coherent beam of light otherwise known as a laser beam. In some embodiments, the term "laser" refers to conventional lasers (such as C0₂, YAG, and fiber lasers), as well as laser diodes.

[0028] The term "syngas" or "synthesis gas" means synthesis gas which is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen.

[0029] In one embodiment, the present invention is directed to providing an underground coal gasification process (UCG) that addresses the main disadvantage of conventional UCG, namely the controllability of the reaction, and the efficiency of the combustion reactions. Coal combustion and gasification are complex processes, which involve many interactions of chemical and physical phenomena. In coal conversion processes, such as combustion or high temperature gasification, the extent of pyrolysis is an important parameter. Increasing amounts of coal converted directly to gaseous species would reduce the remaining material, char, which can be converted by the relatively slow char-gas reactions. The coal pyrolysis and devolatilization is always the first step and plays a fundamental role. Coal rank and properties significantly influence heat and mass transfer as well as reaction rates. Therefore, times, yields, and gaseous emissions depend on the original source material, however there are general findings that one can consider. The key to understanding the phenomena occurring thus lies first in the characterization of the initial coal and then in describing the primary devolatilization phase and the released products. Thermo-chemical conversion of coal in practical systems results from a strong interaction between chemical and physical processes at the micro and also at the reactor level, i.e., the level of the surrounding environment.

[0030] It is well known that coal devolatilization is a process in which coal is transformed at elevated temperatures to produce gases, tar, and char. Functional groups of the original coal are mainly released as gases and can be reasonably predicted by first-order reaction models. Tar, defined as condensable species formed during coal devolatilization, is a major volatile product, up to 50% of coal weight for bituminous coals.

[0031] At low temperatures (or low heating rates), coals initially form char and volatile species (tar and gas), which are still in the condensed phase. The tar in the condensed phase can be released with a proper kinetic rate or can interact with char in cross-linking reactions, which increase the residual char and produce further gas. At high temperatures (or high heating rates) the coals more directly decompose to gas and tar, and always form more aromatic char structures. Lignitic coals first move through an activate state in the condensed phase and then undergo a real decomposition reaction. The transition temperature, where gradually high temperature decomposition prevails, is between 800K for 1200 K depending on the aromatic structure of the coal.

[0032] The description of gas species is simplified. Light hydrocarbon gases that are produced are H₂, CH₄ and a mixture of C₂-C₅ hydrocarbons. The main oxygenated products are CO, C0₂ and H₂0. Other oxygenated species are present at lower concentrations. As an example, formaldehyde, methanol, ketene, and acetic acid can form from primary pyrolysis.

[0033] Upon heating, bituminous coals undergo melting and pyrolytic decomposition, with significant parts forming an unstable liquid that can escape from the coal by evaporation. The transient liquid within the pyrolysing coal causes softening or plastic behavior that can influence the chemistry and physics of the process. The extent of pyrolysis is known to be influenced, directly or indirectly, by temperature, heating rate and exposure time. In standard methods, the amount of coal converted to volatile matter is determined at low temperatures, slow heating rates and long exposure times. As a result, relatively low volatile yields are obtained, and also the resulting char is much less reactive. These effects have been recognized, and some studies have been reported on this aspect. The extent of pyrolysis increases significantly with temperature, with an apparent plateau or a peak in the weight loss curve at 900 - 1100°C. Effective pyrolysis therefore occurs in the region of 500 - 800°C, with greater yield at the higher temperature. [0034] In one embodiment, the present invention is directed to a method of underground pyrolysis of carbonaceous material using laser based thermal desorption/extraction techniques. The laser-based pyrolysis described herein may product variable heating rates, e.g., from 25°C (slow pyrolysis) to 10,000°C (flash pyrolysis) per second. In contrast with conventional heating mechanisms, the present invention uses lasers of sufficient industrial ruggedness, the necessary optical intensities, and efficiencies to radiatively heat coal seams to sufficient levels so as to induce pyrolysis. Without limit to any one particular theory, the advantages achieved by laser- based pyrolysis include: greater levels of pyrolysis, greater rates, higher efficiencies and less waste.

[0035] In one embodiment of the present invention, as depicted in FIG. 3, the methods of the present invention utilize directional drilling techniques to provide an ignition well, production well, and a linkage bore. Laser energy is then injected into the linkage bore, to raise the temperature of the entire bore to an ignition temperature. Gases are then fed into the linkage bore to initiate the pyrolysis reaction across the whole length. The reaction proceeds outwards from the laser, through the coal, until the optimum point is reached (e.g., depending on seam thickness). While not limited to one particular theory, the present achieves a number of advantages over conventional techniques, including: direct delivery of optical power through km long fibers made possible through the provision of high transmission communication S1O2 fibers; the ability to condition specific high-energy intensities required for heating coal to the ignition temperature; the ability to heat the whole length of the linkage bore thereby creating greater area for combustion; the ability to provide direct primary heating of secondary heat sources such as steam injection; high levels of reliability approaching 100,000hrs, necessary for long service life and multiple ignition programs.

[0036] In some embodiments, the present invention results significant energy gains compared to conventional methods. For example, Fig. 4 depicts an embodiment of the present invention, wherein a volume of coal having a width (W) and a length (L) is heated using a laser of the present invention to produce syngas. The following table describes the physical characteristics of an exemplary underground coal deposit: Physical Property Value

Specific heat capacity (J/Kg )¹ 1.38

Density (kg/m3)' 1.35xl0

Calorific value of volatiles 9xl0⁶

(J/m3)²

Pyrolysis Temperature (K) 1 100

Length (m) 600

Width (m) 20

1 - Typical for Bitumen coals

2- Known values for conventional UCG (9-1 1 kJ/m³)

3- Optimum temperature for pyrolysis

[0037] The total energy required, Q, to raise a body of mass, m, from a starting temperature, 77, to a final temperature, T2, is given by

Q = mCp(T₂ - T_l)

[0038] Where, Cp, is the specific heat capacity of Coal. Results of this calculation for a range of operating volumes arc given in the following table:

[0039] Without being bound to one particular theory, the energy gain according to some embodiments of the invention can result in some 70,000 times the energy used to heat the seam to ignition. Additionally, 3x10 Joules of energy are required to raise 180 m of coal to the ignition temperate of 800 °C. Lasers of the present invention include those capable of delivering continuous power outputs up to lOOkW, which would provide the total required energy in a matter of minutes. [0040] In some embodiments, the present invention comprises providing one or more gases into the linkage bore from the injection well in a controlled manner. Without being bound to one particular theory, the one or more gases facilitates the production of syngas. The composition and rate of the one or more gases introduced into the linkage bore can vary depending on the size of linkage bore, amount of carbonaceous material located therein, the temperature required to produce syngas and other variables. In one embodiment, the present invention is directed to a method of controlling the one or more gases provided to the linkage bore to increase syngas producing conditions.

[0041] In some embodiments, the present invention produces a syngas comprising from 1 percent to 10 percent by mole carbon dioxide, from 1 percent to 10 percent by mole carbon monoxide, from 20 percent to 30 percent by mole methane, and from 40 percent to 50 percent by mole hydrogen. The methods of producing syngas described herein offer several advantages to conventional methods including a high ratio of hydrogen gas to carbon monoxide. For example, in some embodiments, the mole ratio of hyrdrogen gas to carbon monoxide of the syngas produced according to methods of the present invention is from 4:1 to 50:1. In other embodiemtns, the mole ratio of hyrdrogen gas to carbon monoxide of the syngas produced according to methods of the present invention is from 10: 1 to 20: 1. In other embodiemtns, the mole ratio of hyrdrogen gas to carbon monoxide of the syngas produced according to methods of the present invention is about 15: 1.

[0042] In one embodiment, the present invention is directed to a ruggedized fiber laser beam delivery system for use the in above described methods. In some embodiments, the laser beam delivery system includes laser injection head technology or optical assemblies capable of achieving desired pyrolysis parameters in an underground setting.

[0043] In one embodiment, the present invention is directed to methods of further processing or refining the syngas. Refining techinques are known to those of skill in the art and include removal of impurities, carbon capture and other gas processing steps. In some embodiments, the present invention the syngas is further refined to produce a clean syngas. The clean syngas can be used to generate power, provide feedstocks for chemical products, provide feedstocks for fuel products, and other similar uses known to those of skill in the art. [0044] Without being bound to one particular theory, an embodiment of the present invention achieves significant cost efficiciencies over conventional coal energy extraction technology. For example, embodiments of the present invention can significantly reduce the number of personel required to operate the production operation, thereby reducing the resources and human capital needed to produce the syngas.

[0045] In some embodiments, the present invention is directed to a method of laser-assisted drilling of wells or bores in underground carbonaceous materials, such as oil shale, wherein the laser emits at wavelength and illumination conditions to meet the absorption bands of water present in the carbonaceous material. For example, granite and shale deposits contain about 5-7 wt% water, which allows for laser-scabbing techniques that rely on the explosive response of the super heated water in the body of the shale or rock, to effect large scale fracking effects and/or removal of material and production of hydrocarbons. In some embodiments, the present invention is directed to methods of extracting hydrocarbons from shale oil by deploying an ultraviolet laser down a bore hole, wherein the ultraviolet laser volatilizes hydrocarbons present in shale oil; the volatilized compounds are then collected, refined and used to create energy, chemical feedstocks, or fuel feedstocks according to methods known to those of skill in the art.

[0046] Embodiments of the present invention will be illustrated with reference to the following examples which should not be used to limit or construe the invention.

Example 1

[0047] The experimental system consists of a steel containment vessel containing a block of dry Bitumen Coal of unknown origin, predrilled with a 6mm bore throughout the length of the specimen. A high power C0₂ laser was focused into the bore, with a ZnSe lens of focal length 100mm, and air assist was blown coaxially through a flat tipped Cu nozzle at a flow rate of 2 1/min. A continuous wave CO2 laser (Rofin Sinar DCOlO) gave an energy output of around 40-lkW Wcm^" (TYPO?? IS at a wavelength of 10.6um. The general procedure was to seal the coal sample chamber into which the laser beam was fired. Gas flowed through the borehole, and then progressed through to a Dreschel jar filled with 60mm of water. Gas exiting the Dreschel jar was fed to a nozzle. Gas samples for various exposure conditions as shown in Table.3, were extracted for subsequent analysis by mass spectrometry The gas exit temperature was measured with a K-type thermocouple.

[0048] Pyrolysis was conducted at various incident laser power levels. All laser powers generated a pyrolytic reaction that occurred rapidly on laser exposure. Both gaseous products and some particulates escaped from the reaction vessel, and the particulates were caught in the liquid volume of the Dreschel jar. Pyrolysis of the samples was a continuous process that could be observed for as long as the air and laser energy was allowed to flow through the system. High levels of ignitable gas were observed for power levels above 150W, as shown in Table 1. On termination of the laser beam above the ignition threshold of 100W, the gas mixture composition changed such that it could no longer maintain ignition of the burn-off flame.

Table 1

200 8 Gas/ignition

200 10 Gas/ignition

200 12 Gas/ignition

[0049] Gaseous products produced above the ignition level of 150W are summarized in the following table:

Average Gas Composition of LUCG Pyrolysis Mole % at 150W Power Level compared to conventional UCG processes such as those described at the Central Mining Institute, Katowice, Poland. Reported May 2015, UK Energy Symposium, Kegworth, UK.

[0050] These gases represent a typical hydrocarbon product mix from low temperature coal carbonization process. Refinement of these products in subsequent catalytic steps such as hydrogenation could significantly increase their calorific value.

[0051] The above results demonstrate the feasibility of delivering a LUCG process for the production of syngas from coal beds. Results have shown that low levels of laser illumination in a narrow bore Bitumen coal deposit of < 150W cm², whilst capable of generating syngas products, is insufficient to convert sufficient level of syngas hydrocarbons for ignition at STP. Higher levels of laser illumination at > 150W cm² are required for the generation of ignitable syngas which contain gas products similar to those find in low temperature carbonisation processes. At this power density, removal of the laser illumination reduced the syngas composition such that a sustainable combustion process was terminated. It is worth noting that the power levels used in these experiments are similar to those found in domestic lighting systems. As such, the process offers the opportunity to use industrial scale laser energy to control Syngas production levels and the possibility to control product yield, since the Syngas composition is heavily dependent on reaction temperature. Moreover, the use of methanation reactions such as catalysts or steam, could significantly enhance the calorific value of the syngas products, converting the hydrogen component into greater levels of CH₄, C₂H₆ and other long chain hydrocarbons.

[0052] While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.

[0053] All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

Claims

What is claimed is:

1. A method of producing syngas from an underground carbonaceous material, comprising the steps of: providing an injection well into an underground carbonaceous material;

providing a production well into the underground carbonaceous material;

providing a linkage bore in the underground carbonaceous material running from the injection well to the production well;

providing a laser into the linkage bore;

heating the carbonaceous material located in the linkage bore with the laser;

producing a syngas; and

extracting the syngas through the production well.

2. The method of Claim 1, further comprising providing one or more gases into the linkage bore from the injection well.

3. The method of Claim 1 , wherein the one or more gases comprises steam.

4. The method of Claim 1, wherein the laser is a high-powered fiber laser capabale of delivering at least 20kW of power.

5. The method of Claim 1, wherein the syngas is produced througha pyrolysis reaction.

6. The method of Claim 5, wherein the reaction temperature is from 700 °C to 1200 °C.

7. The method of Claim 1, wherein the syngas comprises from 1 percent to 10 percent by mole carbon dioxide.

8. The method of Claim 1, wherein the syngas comprises from 1 percent to 10 percent by mole carbon monoxide.

9. The method of Claim 1, wherein the syngas comprises from 20 percent to 30 percent by mole methane.

10. The method of Claim 1 , wherein the syngas comprises from 40 percent to 50 percent by mole hydrogen.

1 1. The method of Claim 1 , wherein the syngas comprises a mole ratio of hydrogen to carbon dioxide of about 15:1.

12. The method of Claim 1, further comprising the steps of: processing the syngas to remove impurities and carbon dioxide to provide a clean syngas; and using the clean syngas to generate power, produce fuel products, produce chemical products or combinations thereof.

13. A syngas composition prepared by a process comprising the steps of: providing an injection well into an underground carbonaceous material; providing a production well into the underground carbonaceous material; providing a linkage bore in the underground carbonaceous material running from the injection well to the production well; providing a laser into the linkage bore; heating the carbonaceous material located in the linkage bore with the laser; and producing a syngas; wherein the syngas compises from 1 percent to 10 percent by mole carbon dioxide, from 1 percent to 10 percent by mole carbon monoxide, from 20 percent to 30 percent by mole methane, from 40 percent to 50 percent by mole hydrogen, wherein th

14. The syngas composition of Claim 13, comprising a mole ratio of hydrogen to carbon dioxide of about 15: 1.