Process for the production of high conductivity, carbon-rich materials from coal

Abstract

A method of producing high conductivity carbon material from coal includes subjecting the coal to a dissolution process to produce a solubilized coal material, and subjecting the solubilized coal material to a pyrolysis process to produce the high conductivity carbon material.

Claims

1. A method of producing carbon material from coal, the method comprising: subjecting the coal to a dissolution process to produce a solubilized coal material; and subjecting the solubilized coal material to a pyrolysis process to produce carbon material, the pyrolysis process including heating the solubilized coal material to between 250° C. and 380° C. for 1-8 hrs and then heating the solubilized coal material to temperatures as low as 700° C. for at least 1 hr.

2. The method of claim 1 in which the dissolution process includes adding one or more reagents, solvents and/or catalysts to the coal.

3. The method of claim 2 in which the reagent/solvent includes iPrCl and/or the catalyst includes AlCl.sub.3.

4. The method of claim 1 in which the dissolution process produces a mineral fraction in addition to the solubilized coal material.

5. The method of claim 1 in which the pyrolysis process includes a gas combustor for applying heat to the solubilized coal material.

6. The method of claim 5 in which the pyrolysis process produces a gas in addition to the carbon material, said gas fed to the combustor as a fuel.

7. The method of claim 1 in which the carbon material has a graphene-like morphology.

8. A method of producing carbon material from coal, the method comprising: subjecting the coal to a dissolution process to produce a solubilized coal material; and subjecting the solubilized coal material to a pyrolysis process to produce the carbon material and a fuel gas used in the pyrolysis process to heat the solubilized coal material, the pyrolysis process including heating the solubilized coal material to between 250° C. and 380° C. for 1-8 hrs and then heating the solubilized coal material to temperatures as low as 700° C. for at least 1 hr.

9. The method of claim 8 in which the dissolution process includes adding one or more reagents, solvents and/or catalysts to the coal.

10. The method of claim 9 in which the reagent/solvent includes iPrCl and/or the catalyst includes AlCl.sub.3.

11. The method of claim 8 in which the dissolution process produces a mineral fraction in addition to the solubilized coal material.

12. The method of claim 8 in which the pyrolysis process includes a gas combustor utilizing said fuel gas for applying heat to the solubilized coal material.

13. The method of claim 8 in which the carbon material has a graphene-like morphology.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:

(2) FIG. 1 is a flow chart depicting the primary steps associated with the production of graphene-like, high conductivity carbon material from coal in one example;

(3) FIG. 2 is a graph depicting extensive coal dissolution demonstrated by fluorescence analysis;

(4) FIG. 3 is a compliation of schematics of materials and SEM analyses; and

(5) FIGS. 4A-4B are graphs depicting a performance evaluation of HCCMs materials in battery electrode formulations.

DETAILED DESCRIPTION OF THE INVENTION

(6) Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.

(7) The preferred process starts with the coal feedstock 1, FIG. 1 that is subjected to a dissolution step 4 using, for example, isopropyl chloride (iPrCl-2) as reagent/solvent and aluminum chloride (AlCl.sub.3-3) as catalysts. The coal is presented to a chamber where the reagents/solvents and catalysts are also introduced. The mixtures are mixed for 1-24 hrs at temperatures ranging from 0° C. to 37° C. The products of this step are a solubilized coal material (SCM) 5 and a mineral fraction 6 that may be suitable for the recovery of trace elements. The solution of SCM is separated from the mineral fraction by filtration and the solvent is evaporated. The SCM intermediates are then subjected to pyrolysis/graphenization at step 7 that produces a high conductivity carbon material (HCCM) product 10 at temperatures as low as 380° C. A gaseous stream 8 is also produced comprising low emission fuels such as methane (CH.sub.4). The low emission fuels can be used for combustion 9 to generate the heat needed for the pyrolysis step 7. The pyrolysis step can be performed using, for example, box furnaces or flow pyrolysis reactors. The pyrolysis step is preferably performed under inert atmosphere (e.g., argon, nitrogen). The pyrolysis step 7 may include heating the SCM material to between 250 and 380° C. for 1-8 hrs and then heating the SCM material to temperatures as low as 700° C. for at least 1 hr.

(8) The process was demonstrated for both anthracitic and bituminous coal feedstocks which account for >45% of the coal found in the US. The process was demonstrated to be economically viable by techno-economic analysis. The HCCM product has also been demonstrated in battery electrode formulations,

(9) Multiple anthracitic and bituminous coal feedstocks were demonstrated to be suitable as feedstocks. All coal samples showed extensive dissolution to produce a solubilized product with high content of polycyclic aromatic compounds as determined by fluorescence measurements as shown in FIG. 2.

(10) The coal dissolution processes may be optimized to produce solubilized coal materials (SCMs) with high yields (>75%, g/g basis). Robust pyrolytic processes were also developed and optimized to produce high conductivity carbon materials (HCCMs) from SCMs. The pyrolytic processes produce gaseous byproducts (e.g., methane) that can be used as low emission fuels. Examples of schematics of materials and SEM analyses of the process steps to convert the coal to the final graphene-like HCCM product are shown in FIG. 3, fluorescence measurements and proton nuclear magnetic resonance (.sup.1H-NMR) analysis indicated the chemical changes associated with isopropylation and extension of the aromatic system.

(11) Key properties of the HCCMs demonstrated the suitability of the HCCMs for electrochemical (e.g., battery) applications: (1) a graphene-like morphology as proven by SEM analysis; (2) a low mineral content as proven by ICP-OES measurements (e.g., Fe<100 ppm) and (3) High surface area as proven by BET analysis (e.g., >50 m.sup.2/g).

(12) Also demonstrated were battery electrodes produced with HCCM using industry established procedures, a requirement for wide-scale adoption. Performance analysis of both cathode and anode HCCM formulations demonstrated the feasibility of using these materials in state-of-the art batteries. NCM 622 cathode formulations showed comparable performance to formulations that use commercial conductive carbons as shown in FIG. 4A. In silicon composite anode formulations, the PSI HOCM silicon exhibited an improved voltage profile upon delithiation compared to an uncoated control as shown in FIG. 4B.

(13) A preliminary techno-economic analysis (TEA) was performed to assess the commercial feasibility of the processes depicted in FIG. 1. The results of the TEA indicated that the overall process can result in an economically viable commercial operation on scale-up. A detailed analysis based on Aspen simulations indicated that process scale is a main contributor to the process economics. A 5× reduction in the payback period was estimated upon an increase of the capacity from 1 tonne-per-day (tpd) to 10 tpd.

(14) Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. Other embodiments will occur to those skilled in the art and are within the following claims.

(15) In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for any claim element amended.