Inventor:

Geoffrey R. Wilson

Cross Reference to Related Applications

This provisional U.S. Patent Application is related to a U.S. Provisional Application

Serial No. 61/064.099 filed February 15. 2008 entitled "Apparatus and Process for Production of Coke and Activated Carbon from Coal Products" and a companion Utility U.S. application Serial No. 12/379.139 filed February 13. 2009 entitled "Apparatus and Process for Production of Coke and Activated Carbon from Coal Products" and both U.S. Patent Applications are of common ownership with the currently filed Provisional U.S. Application.

Background of the Invention

Field of the Invention

The inventions herein described relate to the field of fossil fuels and more

particularly to fuels derived from coal for production of coke and activated carbon

products.

Description of the Related Art

The worldwide demand for energy continues to grow annually with an

ever increasing need to control the energy generation processes to minimize harmful

pollution effects of, for example, emissions into the atmosphere of carbon dioxide or mercury and sulfur by-products. In the United States and other industrial nations, there are expanding

-l- government regulation efforts to significantly improve energy generation processes to avoid harmful pollution, e.g., heavy metals such as mercury and sulfur gases from coal-based power electric generating stations.

The United States and other industrial nations are faced with increasing

pressure to impose tougher limitations on greenhouse gas emissions which again place substantially higher production costs on companies which would be required to pay

substantially higher costs on companies and increase the difficulty of obtaining

governmental permits.

Within the European Union, some of the latest proposals could spark a

trade war over global warming issues and similar political issues of regulating emissions.

Targeted emissions may included emissions of heavy metals such as mercury, as well as emissions of carbon dioxide and sulfur oxides. These emissions would be a very serious problem for the large number of power plants in the United States in which steam turbine generators are driven with steam raised by burning coal.

The United States Governments' Clean Air Mercury Rule mandates a 70%

reduction in mercury emissions from all coal-fired power plants by 2010 and 90%

reduction by 2018. These restrictions will substantially expand the worldwide market for carbon production and are estimated in many technical publications to exceed 500 million dollars in the US. United States provisional application Ser. No. 60/907,822, filed by Dr. Harold H.

Schobert, provides further background information to various aspects of these technical arts and developments.

Summary of The Invention

As is well known to those skilled in the energy production arts in the United States and many industrial countries, coal for many years has been a readily available source of electric energy. However, while coal is the one source of energy for which long term supply contracts have been readily available, governmental regulations are currently seriously considering much stronger restrictions to impose tougher limitations on greenhouse gas emission and thus likely in the future to impose substantially higher costs on the operation of coal-fired power generating facilities by requiring the installation of additional cleaning equipment on the plant gas emissions.

Many industrial power plants are currently exploring many improvements for coal fired power plants not only to restrict or substantially reduce the emissions of carbon dioxide gases but also to substantially reduce any emissions of undesirable gases such as mercury and oxides of sulfur.

According to one aspect, one or more embodiments of the disclosed inventions improve the operation of coal fired power plants by substantially reducing objectionable emissions including mercury and sulfur. According to another aspect, one or more embodiments of the disclosed inventions improve the economic operation of coal-fired power plants which would occur if the exhaust were to exceed anticipated heightened governmental pollution restrictions.

According to another aspect, one or more embodiments of the disclosed

inventions economically improve the operation of coal fired electric generation

plants.

The present inventions disclosed in the Apparatus and Processes,

particularly shown on FIG. 6 for the production of coal derived oils are particularly useful in formulating useful coal derived oils for use in numerous subsequent manufacturing processes including cleaner burning fuels and fabricating diverse manufactured products including improved rubber tires and related products.

Brief Description Of The Drawings

These and other more detailed and specific features of the present invention are more fully disclosed in the following specification, reference being had to the accompanying drawings, in which:

FIG. 1 is a schematic flow diagram of a low cost, coal-solvent extraction process or apparatus.

FIG. 2 is a schematic diagram of a low cost, energy efficient coal-solvent

process or apparatus. FIG. 3 is a schematic diagram of apparatus and process for production of activated carbon from coal.

FIG. 4 is a schematic diagram of apparatus and process for production of coal derived oil.

FIGs. 5A-B are block diagrams illustrating integration of activated carbon production with power plant flue gas clean up.

FIG. 6 is a block, flow diagram of apparatus and processes for the production of coal derived oils.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for purposes of explanation, numerous details are set forth including flow charts and system configurations in order to provide an understanding of one or more embodiments of the present invention. However, it is and will be apparent to one skilled in the art that these details are not required in order to practice the present invention.

Figs. 1 and 2 represent two alternative processes and corresponding apparatus for production of Low Ash Coke and/or activated carbon.

Referring first to FIG. 1, after the de-ashing step a flash step is included to remove oil, suitable for dissolving additional fresh coal, by recycling to the solvent/co-feed tank. Additional recycle co-feed is produced in the final fractionation step. FIG. 2 is identical to FIG. 1 except that the flash step is eliminated and the co-feed is derived entirely from the final fractionation step. One option of the disclosed processes and apparatus offers the production of a substantially ash-free coke, suitable for manufacture of aluminum-smelting anodes. With this option, it is useful to input a substantially ash free feed to the delayed coker.

FIGS. 1 and 2 contemplate procedures which can achieve the required substantially ash free coke. Referring first to FIG. 1, the process entails the following:

(a) Dissolving the coal in a suitable solvent selected from or

functionally equivalent to those on the list at the bottom of each figure and process- derived recycle solvent.

(b) Separating the solid/liquid slurry downstream of the dissolver step,

thereby rejecting almost all the ash and some un-dissolved coal as a solid product.

(c) Feeding the liquid stream resulting from the ash separation step,

which is a solution of coal-derived material in the solvent, to a flash step to

substantially remove the solvent from the coal-derived material.

(d) Feeding the substantially ash and solvent-free material to the

delayed coker.

(e) Distillate liquid products from the delayed coker are either utilized

as a single liquid product or separated into typical refinery fuel fractions for further upgrading, usually by hydrotreating and/or hydrogenation.

(f) The solid coke product of delayed coking may then be utilized either as anode grade coke or may be further processed into activated carbon. Activated carbon may be utilized for typical applications such as absorption and purification and may also be used to capture environmentally undesirable heavy metals, such as mercury or arsenic, contained in coal or heavy oil burning power plant flue gases produced during the combustion of the fuel. Graphite is also a potential product of this process.

In anode production, the form of carbon itself is significant, with the

anisotropic form of carbon being desired. To achieve this decant oil is a desirable

petroleum derived stream.

In the variation illustrated in FIG. 2, the solvent flash is eliminated,

resulting in a simplified process and a reduction in equipment, associated capital and a heat consuming step.

FIG. 3 illustrates a flow scheme suitable for production of activated

carbon from coal which is suitable for reduction of heavy metals, such as mercury and arsenic in power plant flue gas. In power plant application integration of the activated carbon production process in to the power plant is desirable. In this application, within reason, the ash content of an activated carbon is not critical, particularly where a low cost product is required. In this application the level of ash rejection upstream of the coker is not critical and may be eliminated completely. In addition, the basic structure of the carbon need not be isotropic, which offers more latitude in the nature of the

petroleum feed to the coker, which could quite be possibly a resid, and not the more

expensive decant oil. Therefore, feeds to the delayed coker may include coal plus

resid, a low value refinery product. FIG. 4 contemplates production of a coal derived hydrocarbon product suitable for exporting to existing petroleum refineries for upgrading into fuels, thereby supplementing the need for imported crude oil.

FIGs. 5A-B are block diagrams illustrating integration of activated carbon production with power plant flue gas clean up.

FIG. 6 is a block, flow diagram of apparatus and processes for production of coal derived oils.

Many of the functional components shown in FIG. 5 are similar to the corresponding components or functions of FIGs. 1-4. The illustrated operational components of the coal driven electric power plant generator include a conventional coal based power generation system (with a coal feeder, not shown), as well as a mercury capture system. The activated carbon products produced according to the described processes may be input to the mercury capture system in order to further the reduction or elimination of undesirable emissions as described above. As also indicated, the CO2 from the combustion flue gas may be fed back to the process of producing the activated carbon. For improved efficiency in solvent extraction the heat recovery from the power generation system is intended to keep the coal slurry operating at a preferred operating temperature in the range of 200-400° Celsius. The input to coal-solvent slurry includes the coal, preferably crushed or pulverized, and the solvent preferably selected from the listing of solvents illustrated in FIGs. 1 and 4. Referring first to FIG. 5 A, the coal-solvent slurry is heated to the preferred operation temperature as noted. After the coal-solvent slurry, which is activated by a power agitator, not shown, reaches the desired coal dissolved range of sixty to seventy percent of the coal charge, the ash separator removes ash and un-extracted coal. After this removal by the ash separator the mixture of un-dissolved coal and dissolved coal- solvent liquid is input to the delayed coker. The CO2 from combustion flue gas can be fed to the delayed coker, or alternatively, directly to the activated carbon unit.

Where the flue gas is fed to the delayed coker, it may react therein as described, but even if the temperature is not sufficient to consume the CO2, the gas will pass to the activated carbon unit where the operating temperature is higher, to ensure a reaction that will consume the CO2. Output from the activated carbon production unit is transferred to the mercury capture system and the exhaust flue control solution to avoid exhaust of mercury from the exhaust flue of the electric power plant. Output from the delayed coker also results in electrode grade low ash coke, which for example, produces coke products for the manufacture of aluminum-smelting anodes for sale to the aluminum industry.

Mixing coal with a very heavy solvent, such as vacuum resid, coal tar pitch, or petroleum pitch, and then feeding this mixture into a fractionator or a coker/activation furnace with CO2 and/or steam could be a direct route to an activated carbon product with a reduced number of processing steps.

FIG. 5B illustrated the processes wherein the ash separator is omitted.

This results in the process that does not generally result in sufficient yield of electrode grade low ash coke, but does provide a more economical production of activated carbon usable for undesirable emissions reduction. Referring now to FIG. 6, the preferred Process and Apparatus of

applicant's embodiments will now be described. The process begins by combining a pulverized coal from a coal bin with a coal solvent entered into a coal slurry from a solvent cofeed unit. As will be hereinafter further defined, the mixture of pulverized soft coal and the coal solvent selected to the list of solvents at the bottom of FIG. 6 are combined in the coal slurry bin in predetermined proportions as will be well known to those knowledgeable in the coal energy arts dependent upon various factors as herein- above described, depending, in part, on the grade of coal selected for the process and the types of end products to be manufactured. In the U.S. market there are increasingly complex federal regulations intended to reduce pollution for reducing CO2 or SO2 gas discharges.

As hereinafter discussed in further detail, the coal slurry is agitated in the coal slurry or coal dissolver at a temperature in the range of 200 to 500° centigrade. Further, the agitation of the coal slurry is generally continued until in the order of 60% to 70% by weight of the pulverized coal is dissolved.

After the coal slurry is appropriately dissolved, the remaining ash and any unextracted coal is removed to produce a substantially ash-free coal slurry liquid.

Thereafter the filtered substantially ash free coal slurry liquid is fed into a

fractionator or delayed coker unit for further heat treatment process steps as will be hereinafter described in further detail. Preferably at this step a portion of the coal solvent is recycled from the fractionator and is returned to the co-feed unit to be combined with additional pulverized coal input into the coal slurry unit to thereby continue the process. Preferably agitation of the coal slurry continues until in the order of 70% by weight of the pulverized coal is dissolved in the coal slurry or dissolver unit before the ash-free coal liquid is introduced into a fractionator unit 68 for further heat treatment. The output of the fractionator unit is fed to a final storage unit where the produced coal derived oils are stored for export or transfer to a user in other manufacturing processes.

Referring again to FIG.6, applicant's preferred apparatus for production of coal derived oils will be described. An input coal receptacle 60 is prepared to receive pulverized coal and a coal solvent co-feeder 62 is arranged to receive a coal solvent with the pulverized coal and coal solvent being loaded in predetermined proportions in accordance with the parameters of the predetermined desired end product .

The respective outputs of the pulverized coal container 60 and the coal solvent co-feeder 62 are fed into the coal slurry agitator 64. The dissolver 65 has an operating pressure in the range of 100 to 3000° psig and is arranged to receive the output of the coal slurry agitator 64 which preferably is driven or cycled until in the order

of 70% by weight of the pulverized coal has been dissolved. In the preferred

embodiment of applicant's apparatus for production of coal derived oils, the ash-free slurry is agitated at a temperature in a range of 200 to 400 or up to 800 degrees centigrade for certain end products. An ash separation unit 67 accepts the output of the dissolver unit 65 and feeds a fractionators 66 to further heat treat the ash-free coal slurry in a plurality of temperature ranges depending upon the specific types of products to be manufactured. For example, a typical fractionator 66 usually handles several boiling range products, for example: a gasoline fraction in the range of 100 to 425°

centigrade; a coal based oil fractionators in a range of 425 to 800° centigrade, and

another coal based product above 800° centigrade. As will be known to those

skilled in the coal based oil technologies, a much simpler solvent flash unit (not

illustrated) could be utilized to replace the more expensive fractionator unit 66 to

accommodate certain lower end products.

As illustrated in FIG. 6, a solvent recycle line connects an output of the

fractionator unit 66 (or lower cost flash unit) and is coupled to the input of cofeed 62 to recycle recovered coal solvent to continue operation of the described process or

production apparatus. The output of the fractionator 66 is fed to the input of reservoir 68 for storing the produced coal derived oils for export to other commercial users via output delivery port 70.

Referring again to the list of alternative coal solvents at the lower end of

FIG. 6, those skilled in Coal Derived Oils Technology will be familiar with the listed or similar alternative coal solvents for use in applicant's disclosed

embodiments.

[0047] For a more complete understanding of the structure and operation of the solvent extraction apparatus illustrated in FIGs. 1 through 5 and FIG. 6, it may be helpful to have specific reference to the sequential Steps of Table 1, as set forth below:

Table 1

Step 1- Fill the coal-solvent slurry at a preferred ratio of 10:1 by weight of coal to a light cycle oil or alternate solvents from the list on Figs. 1 through 4 and Fig. 6. Step 2- Agitate the coal solvent slurry in the mixing unit until in the order of 60% to 70% of the coal slurry has been dissolved at the preferred operating temperature in the order of 350 degrees C or higher for specific end products.

Step 3- Separate any coal ash from undissolved coal and the dissolved coal-solvent liquid in a separator unit.

Step 4- Feed the output of the separator unit which comprises approximately 30% undissolved coal and 70% dissolved coal and solvent liquid into fractionator or a delayed coker.

Step 5- Feed the output of the fractionator or alternatively a delayed coker unit to several selectable separate processing units in predetermined portions: a coker to produce very low ash coke for manufacturing aluminum-smelting anodes, a process unit for combining carbon dioxide with the output of the delayed coker to produce activated carbon products, and diverting a desired portion of the dissolved coal-solvent liquid or recycling to the solvent extraction unit or for further distillate refinery processing. As further illustrated in FIG. 6, the output from the fractionator of coal derived oils is coupled to a storage unit or to an output delivery port or tank 70.

[0049] In conclusion, the forgoing description of the various embodiments of the applicant's invention of coal derived oils have been provided for purposes of illustration only and numerous changes may be made without departing from the spirit and scope of the disclosed and claimed embodiments of the invention. For this reason reference should be had solely to the appended claims for determining the scope of the present invention.

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