Patent Abstract:
A method for treating coal includes drying coal in an initial drying step. The dried coal is pyrolyzed in a pyrolysis step to form coal char and evolved gases. The coal char is eventually cooled and blended. The evolved gases are condensed in at least two, preferably three or more, distinct zones at different temperatures to condense coal-derived liquids (CDLs) from the evolved coal gas. Noncondensable gases may be returned to the pyrolysis chamber as a heat-laden sweep gas, or further processed as a fuel stream. The CDLs may optionally be centrifuged and/or filtered or otherwise separated from remaining particulate coal sludge. The sludge may be combined with coal char, optionally for briquetting; while the CDLs are stored. Precise control of the condensing zone temperatures allows control of the amount and consistency of the condensate fractions collected.

Full Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority of provisional application 61/750,590 filed Jan. 9, 2013. This application is also related to published U.S. Patent Applications 2011/0011722, 2011/0011720, and 2011/0011719, each published Jan. 20, 2011; and to U.S. Patent Publication 2013/0062186, published Mar. 14, 2013, entitled PROCESS FOR TREATING COAL USING MULTIPLE DUAL ZONE STEPS. 
     
    
       [0002]    The disclosures of all of the above patent publications and applications are incorporated herein by reference in their entirety. This invention was made with no U.S. Government support and the U.S. Government has no rights in this invention. 
     
    
     TECHNICAL FIELD 
       [0003]    The present invention relates to the field of coal processing, and more specifically to a carbonization process for treating various types of coal for the production of higher value coal-derived products, such as coal char, coal liquids or oils, gaseous fuels, water and heat. More specifically, the present invention relates to processes and apparatus for the more efficient recovery of (1) coal-derived liquids (CDLs) from the gases driven off, and (2) the char produced from coal during pyrolysis. It is applicable to bituminous, sub-bituminous and non-agglomerating lignite ranks of coal. 
       BACKGROUND OF THE INVENTION 
       [0004]    Coal in its virgin state is sometimes treated to improve its usefulness and thermal energy content. The treatment can include drying the coal and subjecting the coal to a pyrolysis process to drive off low boiling point organic compounds and heavier organic compounds. This thermal treatment of coal, also known as low temperature coal carbonization, causes the release of certain volatile hydrocarbon compounds having value for further refinement into liquid fuels and other coal-derived liquids (CDLs) and chemicals. Subsequently, the volatile components can be removed from the effluent or gases exiting the pyrolysis process. Such thermal or pyrolytic treatment of coal causes it to be transformed into coal char by virtue of the evolution of the coal volatiles and products of organic sulfur decomposition. The magnetic susceptibilities of inorganic sulfur and iron in the resultant char are initiated for subsequent removal of such undesirable components as coal ash, inorganic sulfur and mercury from the coal char. 
         [0005]    It would be advantageous if agglomerating or bituminous coal could be treated in such a manner that would enable volatile components to be effectively removed from the coal at more desirable concentrations, thereby creating a coal char product having reduced organic sulfur and mercury. It would be further advantageous if bituminous coal could be refined in such a manner to create a second revenue stream (i.e., condensable coal liquids), which could be recovered to produce syncrude and other valuable coal products. 
         [0006]    For example, even CDLs collected and separated may contain undesirable particulate matter—as much as 5-10% by weight by some estimates. These small, micron-sized particulates are generally undesirable, particularly if the CDL is to be further processed or refined by additional equipment. Therefore it would be advantageous to remove significant portions of these fine particulates. 
       SUMMARY OF THE INVENTION 
       [0007]    In a broad aspect, a process for treating coal is described. The process builds on low temperature coal carbonization to separate coal into multiple components, including: coal char, coal-derived liquids (CDLs), and a gaseous fuel also known as syngas. The CDLs are further fractionated into multiple components in some embodiments. For example, in one aspect the invention is a method for treating effluent gases evolved from a coal pyrolysis process, the method comprising: 
         [0008]    passing the evolved gases through at least two distinct condensation zones, each zone being maintained at a different temperature to condense to liquids the different boiling point fractions of the evolved gases; 
         [0009]    (optionally) directing the liquids from each condensation zone to one or more separation units to separate particulate sludge and/or impurities from the condensed liquids; and 
         [0010]    directing the condensed liquids from each separation unit to its own separate storage tank, wherein the temperature of each condensing zone is controlled within a predetermined temperature range to collect a desired CDL fraction in each of the storage tanks. 
         [0011]    In another aspect the invention is a method for treating effluent gases evolved from a coal pyrolysis process, the method comprising:
       drying coal to remove moisture;   pyrolyzing dried coal in one or more pyrolysis chamber(s) to form coal char and evolved gases;   passing the evolved gases through at least two, preferably three or more, distinct condensation zones of an absorber, each zone being maintained at a different temperature to condense to liquids the different boiling point fractions of the evolved gases;   optionally directing the liquids from each condensation zone to one or more separation units to separate particulate sludge and/or impurities from the condensed liquids;   directing the sludge (and particulates) separated from liquids at each separation unit to a common blending area with the coal char; and   directing the condensed liquids from each separation unit to its own separate storage tank, wherein the temperature of each condensing zone is controlled within a predetermined temperature range to collect a desired fraction CDL in each of the storage tanks.       
 
         [0018]    The methods may include further processing of any of the collected CDL, such as separation or purification by means such as centrifugation, filtration and the like. Particulates and sludge removed from the CDLs in these purification steps may be used in briquetting. 
         [0019]    In other aspects the methods include further processing of the remaining gas stream after CDLs have been removed. For example, a portion of the gas stream may be re-cycled to the pyrolysis chamber(s) for use as a sweep gas to add direct heat. Another portion may be cooled to remove water vapor that remains and is stored as a dried gaseous fuel. Such a dried gaseous fuel has a high heating value, for example greater than 8,000 BTU/lb (20.4 MJ/kg). If being pumped long distances, it may be re-heated, for example to 50-70 C, typically 55-65 C, to reduce the likelihood of any components condensing in the conduits. The proportion for each such use can vary from 0 to 100%. 
         [0020]    In another variation, the gas stream evolved from the absorber may be further processed with an electrostatic precipitator (ESP). The ESP can collect oil mist particles that are entrained in the stream and re-blend them with a light oil CDL fraction. 
         [0021]    In a three zone absorber designed to collect and process CDLs from coal, the temperature set points for the three zones may include sequentially, from about 450 F (232 C) to about 550 F (288 C) for the heavy CDL fraction, from about 250 F (121 C) to about 400 F (204 C) for the middle CDL fraction, and from about 150 F (65 C) to about 250 F (121 C) for the light CDL fraction. 
         [0022]    In another variation, the effluent gases from the pyrolysis process are first passed though a high temperature cyclone to remove char fines, and/or a venturi to mix and nucleate the heaviest condensable CDLs before they are admitted to the absorber. This step increases the capture of the desired CDL fraction in each zone by removal of nucleation sites for mist formation. 
         [0023]    In another variation, any or all of the following fractions may be used as fuel and/or binder to form pellets or briquettes: the coal fines from the cyclone; the bottom bleeds from the highest temperature zone of the absorber; all or a portion of the heavy CDL fraction; all or a portion of the sludge and fines from optional purification of the CDLs. 
         [0024]    Various other embodiments are described herein as well. 
         [0025]    Various advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a generalized process diagram for a pyrolysis or carbonization process with multiple component fractions. 
           [0027]      FIGS. 2A to 2C  are sections of a schematic illustration of a process for treating the effluent gases formed by the pyrolysis of various types of bituminous coal. 
           [0028]      FIG. 3  is a chart showing a series of C 6 + hydrocarbon compounds and their equilibrium vapor pressure as a function of temperature. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The process pertains to treating non-agglomerating coal and various types of bituminous coal for the production of coal derived liquid (CDL) and other higher value coal derived products, such as a high calorific value, low volatile, low ash, low sulfur coal, also known as char, suitable for a variety of uses in industry, including metallurgical uses and power production, including forming the char into briquettes. 
         [0030]      FIG. 1  illustrates the process at a very general level. Coal  10 , is heated in one or more drying and/or pyrolysis steps which apply heat as indicated at  12 . As noted above, this process is sometimes referred to as low-temperature carbonization. The pyrolysis process produces three products, water vapor  14 , effluent or evolved gases  16 , and coal char  18 . These three products are cooled which, for gaseous products, leads to some condensation as indicated at  20 . Water vapor  14  is condensed to water  22 , and may be used for further processing steps. While the coal char  18  is one desirable product, the volatile effluent gases  16  from the coal may be refined to create a second revenue stream. The evolved or effluent gases include some gaseous components that will not condense at room temperature and these remain as hydrocarbon gases  24  or syngas, which is a third potential product and revenue stream. However, other components of the effluent gases  16  will condense and are referred to generically as coal-derived liquids or CDLs  26 . According to the invention, CDLs  26  may be further fractionated into multiple components, such as low boiling point light oils  28 , mid boiling point medium weight oils  30 , and high boiling point heavy oils  32 . Finally, the evolved gases may include char fines that may condense as a sludge  34 . This general process is described in more detail below. 
         [0031]      FIG. 2  is a schematic illustration of a process for treating effluent gases  16  evolved from coal that has been pyrolyzed.  FIG. 2  is divided into three sections,  2 A,  2 B and  2 C, designed to be viewed as one large schematic. At various points, the lines from one section connect to lines of another section. Furthermore, at several points in the diagram a roman numeral inside a diamond indicates a particular process sampling point or location. These process sampling point locations coincide with those shown in Table B, which give some properties of the process stream at each particular location identified. 
         [0032]    An optional drying step removes excessive moisture from the coal. The dried coal is then fed to a pyrolysis chamber where the coal is pyrolzyed as is known in the art at temperatures typically between about 500-600 C. Multiple pyrolysis stages may be used if desired. The pyrolysis is done with low oxygen and drives off impurities as evolved gases to improve the efficiency of the resulting coal as fuel, a process known as “beneficiation” of the coal. 
         [0033]    Particle carryover in the effluent gas stream exiting from a pyrolysis chamber such as a fluidized bed has been estimated to be as high as about 15-20% by weight. These particles comprise char fines and quinoline insoluble particles. In one known example, these solids amounted to about 16.1% by weight. Consequently, the effluent gas stream may optionally pass through a high temperature, high efficiency cyclone separator  36  which separates out the carbon fine particulates 38. Solid particle loads can be reduced to as little as 1.0% by weight using such separators. Suitable cyclone separators are available from suppliers such as Ducon, 5 Penn Plaza, New York, N.Y.; Fisher-Klosterman, Louisville, Ky.; or Heumann Environmental, Jeffersonville, Ind. For example, some Heurmann units are designed to remove 95% of the minus 5 micron particulates carried in the pyrolysis effluent gas stream. The particulates  38  so removed from the effluent gas stream can be conveyed to a separate collection means or re-injected into the fluidized bed pyrolysis chamber. Preferably, the particulates  38  are transported from the separate collection means to be added downstream to the sludge and subsequently added to the coal char briquetting or shipped with the coal char in bulk form. 
         [0034]    The evolved gases and any remaining particulates escaping the cyclone  36  are fed to the inlet of a variable throat venturi  40 . During the condensation process, pure segmentation in fractionation is hampered by the formation of high boiling point (BP) mist or droplets which serve as nucleation sites, at which lower BP fractions may coalesce prematurely while still at high temperatures. It is desirable therefore, to separate remaining particulates and the high BP nucleates at an elevated temperature while the desirable lower boiling point hydrocarbon compounds are still vaporous. The venturi  40  may be operated from about 350 C to 450 C to remove these nucleates and cause forced nucleation of many of the high BP components. This may be followed by forcing the mist into the absorber  54  via a port  56  that is deliberately angled downwardly to the initial collection chamber  57  to prevent the high BP mist particles from continuing upward into the lower temperature condensing zones above. In testing, as much as 95% of the char fines and quinoline insoluble particulates were retained in with the high BP fraction in the lowest zone of the absorber  54 . 
         [0035]    The ventruri  40  also serves to wet and mix the evolved gases. A source of fluid  42  may be heated or cooled as needed at heat exchangers  44 ,  46  fed by sources of heating fluid  48  or cooling fluid  50 . The fluid source  42  is heated or cooled to a desired temperature (e.g. 350-500 C) in response to temperature sensor T, temperature control module TC, and temperature control valves TCV, and is then fed to the inlet of the venturi  40  to mix and wet the effluent gases  16 . Pressure sensors, P, monitor the pressure above and below the throat of the venturi  40  and a pressure differential control module, DPC, adjusts the venturi throat to maintain a predetermined pressure differential. Such venturi devices suitable for use with the invention are available from: Sly, Inc., Strongsville, Ohio; Envitech, Inc. San Diego, Calif.; Monroe Environmental, Monroe, Mich.; and AirPol, Ramsey, N.J. The outlet of the venturi feeds line  52  which feeds the inlet of a quench tower or absorber  54  (See  FIG. 2B ). 
         [0036]    The quench tower or absorber  54  condenses and separates volatile components from the evolved gases  16 . According to an embodiment of the invention, the absorber  54  is divided into multiple condensation zones, i.e. two or more, preferably at least three zones. Referring to  FIG. 2 , three such condensation zones are shown, such as zones A, B and C, as identified by process sampling points IV, VI and VIII. These zones are maintained at increasingly lower temperatures as one progresses upward in the absorber tower. The three condensation zones result in heavy, mid and light CDL fractions being condensed and separated from the evolved gases. Additionally, a fine mist of additional light condensables may escape entrained in the gas stream, and may be processed as described below. While three such condensation zones are depicted, it will be understood that any number of multiple stage condensation zones is possible. The greater the number of condensation zones and the finer the temperature control in each one, the more uniform will be the condensed fractions resulting as the CDL components. 
         [0037]    Other than the temperature at which each zone is set to condense, the structure of each is similar, so that only zone B is described in detail herein, it being understood that each such zone will have similar structures and function. Liquid condensed in zone B drains into a chimney tray  58 . The chimney tray  58  allows gas to pass through a multiplicity of chimney ducts or tubes while collecting the liquid in the volumetric space above the tray and surrounding the chimney ducts. The condensed liquid is drawn away from the chimney tray  58  by means of a pump  60 , optionally through a valve  62  and strainer  64 . A level meter L and a level control LC maintain the draw rate so as maintain a minimal threshold level at the bottom of zone B. The withdrawn liquid is carried to a heat exchanger  68  where it transfers its heat to a coolant fluid that is pumped through the heat exchanger  68  from a source  70  and to which it may return in a loop. A temperature sensor T monitors the temperature of the liquid exiting the heat exchanger  68  and temperature controller TC controls the temperature control valve TCV to control the flow of coolant to the heat exchanger  68 . 
         [0038]    A portion of the cooled fluid exiting the heat exchanger  68  is diverted back to the top of zone B and to sprayers  72  which spray the liquid onto the hot gases to initiate further condensation, thus completing the loop. A flow meter F and flow control FC control the flow control valve FCV to maintain a constant flow rate to the sprayers  72 . The remainder of the cooled fluid exiting the heat exchanger  68  (process sampling point VII) is carried to an optional separator, such as centrifuge  74 , for further processing that will be described momentarily. 
         [0039]    Zones A and C have similar liquid sprayer loops that are cooled by heat exchangers and aid in condensation. These heat exchangers are conventional in using a coolant fluid to exchange heat with the hot gases thereby cooling them to condense the volatile components with boiling points below the target temperature range, while not condensing volatile components with lower boiling points. Thus, the temperature set points for zones A, B, and C are all likely to be different, however, with the set point decreasing in succession from A to C. Typical temperature ranges for a three zone absorber are discussed below. The excess condensed liquid from Zone A (process sampling point V) is carried to an optional separator, such as centrifuge  76 , and the excess condensed liquid from Zone C (process sampling point IX) is carried to an optional separator, such as centrifuge  78 . Also, bottoms may be bled from the strainer below Zone A, to combine with sludge and/or use as a binder in a subsequent pelleting or briquetting operation. 
         [0040]    Although shown as a loop configuration in  FIG. 2B , heat from the heat-exchanged coolant may optionally be recovered in a heat recovery area to be used for other heating needs such as, for example, a sweep gas, a warmer or dryer, or any other process step requiring the input of heat. 
         [0041]    Within each zone at the temperature (or range) of its set point, a certain fraction of the volatiles condense depending on their boiling points and vapor pressure within the mixture. Assuming a light CDL loop target temperature in Zone C of about 77 C+/−5, as shown in the schematic of  FIG. 2 , a certain percentage of the condensable evolved gases remain as a mist of fine droplets in the gas stream. This mist evolves from the absorber at the top  80  (process sampling point X) and may be fed to a gas cleaning unit or particle separator, such as a wet electrostatic precipitator (ESP)  82 , which is used in the gas cleaning area to separate the mist droplets from the gas stream. The mist droplets contain additional light CDL and may be combined with previously fractionated light CDL as shown in  FIG. 2  (process sampling point XI). Suitable ESPs are available from Lodge (KC) Cottrell, Inc., The Woodlands, Tex.; and/or Hamon Research-Cottrell, Inc., Somerville, N.J. 
         [0042]    Suitable absorbers or quench towers are assembled from parts made by commercial suppliers such as Koch-Glitsch, LP, Wichita, Kans.; Sulzer Chemtech USA, Inc., Tulsa, Okla.; Raschig-Jaeger Products, Inc., Houston, Tex.; and others. 
         [0043]    The gas stream leaving the precipitator  82  often contains traces of condensable hydrocarbon compounds and typically 20 to 30 weight % uncondensed moisture, the temperature typically at about 75 to 85C. For use as a fuel, it is desirable to remove some or most of the moisture and thereafter to reheat the gas to eliminate further condensation of either hydrocarbon compounds or water. Carryover of water is undesirable in the fuel as it lowers the calorific heating value of the fuel gas. Carryover of traces of condensable hydrocarbons which may condense in long gaseous fuel delivery conduits causing buildup and reduced flow path en-route to the fuel point of use is undesirable. Accordingly, the gas stream is then carried to a cooler  84  ( FIG. 2C ) where it is cooled to about 50 C in order to remove any water vapor that may remain. Water collects in a sump  86  (process sampling point XVI) and may be waste or used for other purposes. 
         [0044]    The noncondensable gas that exits the cooler  84  is known as syngas or gaseous fuel and generally is composed of hydrogen, carbon oxides, water, and C 6  or shorter hydrocarbons. Table C (Below) lists many of these components. This process gas is sometimes burned off as flame, but may also be an important product gas itself. Optionally, this gas is reheated by a heat exchanger  88  to avoid condensation in long pipelines, and pumped by fan  90  to storage or to a location for further use, such as a fuel. The process gas may flow at typical rate of 6,000 to 10,000 kg/hour and may be reheated to about 60 C prior to being piped to a gas user. 
         [0045]    In an important variation, a portion of the gas stream may be taken from a split point directly after the electrostatic precipitator  82  (process sampling point XIV) and pumped by fan  92  to the pyrolysis chamber(s) for use as a sweep gas without cooling. From 0% to 100% of the gas stream may be used for pyrolysis sweep gas, more typically from 40% to about 80%. If any portion of the gas stream is desired for pyrolysis, it is more energy efficient to bypass the cooler  84  and re-heater  88 . 
         [0046]    Depending on the type of coal and pyrolysis conditions, a typical three condensation zone absorber may be designed and configured to condense about 20% (+/−5%) heavy CDL fraction, about 25% (+/−5%) mid CDL fraction and about 20% (+/−5%) light CDL fraction in the three condensation loops as shown in  FIG. 2 . An additional 35% (+/−10%) by weight of light CDL condensables may exist in the mist droplets that escape to the electrostatic precipitator  82  which, when combined with the other light CDL fraction, yields about 55% of the total condensable portion. 
         [0047]    As previously noted, the CDL condensed in Zone B is led to a centrifuge  74  ( FIG. 2C ). More generally, the condensed CDLs form each condensation zone may be further purified, filtered or separated to remove unwanted components. Separations may include any one or more of centrifuges, cyclone separators, ultra-high efficiency cyclones, electrostatic precipitators (ESP), drop boxes, filters of suitable pore size, etc. to remove fine particulates. Suitable centrifuges are commercially available from Flottweg, North America, Independence, Ky.; GEA Westfalia Separator Group, Northvale, N.J.; and Haus Centrifuge Technologies, (Welco Expediting, LTD) Calgary, Alberta, CA, among others. Suitable filters are commercially available from, for example, Towner Filtration, Twinsburg, Ohio. 
         [0048]    In one embodiment, the heavy CDLs are led to centrifuge  76  and the supernatant CDL portion may further be passed through a filter  96 . These optional separation steps further purify the heavy CDLs, removing sludge and particulates. Similarly, medium CDLs are led to centrifuge  74  and the supernatant CDL portion may further be passed through a filter  94 . These optional separation steps further purify the medium CDLs, removing sludge and particulates. Finally, light CDLs are led to centrifuge  78  and the supernatant CDL portion may further be passed through a filter  98 . These optional separation steps further purify the light CDLs, removing sludge and particulates. The sludge and particulates from each of the three centrifugation and three filtration steps may be combined and used elsewhere, for example in briquetting processes. 
         [0049]    Even though we refer to fractions as high, medium and low BP fractions, it is well understood that there is a distinction between boiling points (BP) and the actual temperature at which the condensable components will condense. Each condensable component “boils” at the temperature at which its pure vapor pressure equals atmospheric pressure. In contrast, the fractional condensation temperature (FCT) takes into account the fact that these compounds are in mixtures and each exerts only a partial vapor pressure—they are not pure. The fractional condensation curve table below (Table A) correlates the condensation zone target temperature with the approximate percent (by weight) of the CDL fraction that will condense under typical conditions, making certain assumptions about the partial pressure level of condensable components vs. the non-condensable components. Component-specific FCT estimates are discussed below in connection with  FIG. 3 . 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE A 
               
             
             
               
                   
               
               
                 Fractional Condensation Temperatures (FCT) 
               
             
          
           
               
                   
                   
                 Condensation Curve, 
                 Estimated Condensation 
               
               
                 Temp 
                 Temp 
                 assuming 100% 
                 Curve, assuming 25% 
               
               
                 (F.) 
                 (C.) 
                 condensables 
                 condensables 
               
               
                   
               
             
          
           
               
                 995 
                 535 
                  0% 
                  0% 
               
               
                 937 
                 502.8 
                  5% 
               
               
                 885 
                 473.9 
                 10% 
               
               
                 849 
                 453.9 
                 15% 
               
               
                 822 
                 438.9 
                 20% 
                  5% 
               
               
                 794 
                 423.3 
                 25% 
               
               
                 766 
                 407.8 
                 30% 
               
               
                 738 
                 392.2 
                 35% 
               
               
                 715 
                 379.4 
                 40% 
               
               
                 687 
                 363.9 
                 45% 
                 10% 
               
               
                 685 
                 362.8 
               
               
                 658 
                 347.8 
                 50% 
               
               
                 629 
                 331.7 
                 55% 
               
               
                 601 
                 316.1 
                 60% 
               
               
                 595 
                 312.8 
                   
                 15% 
               
               
                 572 
                 300 
                 65% 
               
               
                 541 
                 282.8 
                 70% 
               
               
                 512 
                 266.7 
                 75% 
               
               
                 495 
                 257.2 
                   
                 20% 
               
               
                 483 
                 250.6 
                 80% 
               
               
                 449 
                 231.7 
                 85% 
               
               
                 420 
                 215.6 
                   
                 30% 
               
               
                 414 
                 212.2 
                 90% 
               
               
                 369 
                 187.2 
                 95% 
               
               
                 350 
                 176.7 
                   
                 40% 
               
               
                 300 
                 148.9 
                   
                 50% 
               
               
                 270 
                 132.2 
                 100%  
               
               
                 260 
                 126.7 
                   
                 60% 
               
               
                 230 
                 110 
                   
                 70% 
               
               
                 200 
                 93.3 
                   
                 80% 
               
               
                 160 
                 71.1 
                   
                 100%  
               
               
                   
               
             
          
         
       
     
         [0050]    In selecting a target temperature for each zone, it should be recalled that all volatile components having a fractional condensation temperature (FCT) above the target temperature for the particular zone are likely to condense in that zone. Thus, tradeoff decisions are to be made about how many fractions are desired and how fine or broad a temperature window is needed for capturing that entire component without undue impurities. These are traded off against the cost and efficiency of additional condensation loops, and the desire and ability to further refine the fractions as collected. It should be understood that the target temperature to maintain in the condensation loops will typically be at the lower end of the ranges described herein, in order to recover all condensable components in the desired fraction. 
         [0051]    For example, in a three loop condensation zone process as described in  FIG. 2 , the temperature may be set to collect three fractions in the condensation loops—heavy, middle and light fractions—having respectively approximately 20%, 25% and 20-25% by weight of the condensable components. Another 30-35% light CDL found in the entrained mist may be precipitated and combined with the 20-25% from the exchange loop. With these assumptions, the heavy fraction target might be set at a temperature from about 450 F (232 C) to about 550 F (288 C), preferably about from about 470 F (243 C) to about 530 F (278 C). The middle fraction target might be set at a temperature from about 250 F (121 C) to about 400 F (204C), preferably about from about 250 F (121 C) to about 350 F (177 C). The light fraction target migh t be set at a temperature from about 150 F (65 C) to about 250 F (121 C), preferably about from about 160 F (71 C) to about 220 F (105 C). 
         [0052]    It will be understood that a desire to collect additional fractions will require additional target temperatures determined according to similar logic, but with narrower temperature windows. Similarly, a desire to collect fractions that are smaller or larger than the assumed 20% heavy, 25% mid, 20% light CDLs (plus 35% additional light CDL in the mist) will require adjustments to the target temperatures as well, based on theoretical BP curves modified to fit the altered assumptions, or on empirical experience. 
         [0053]    More specifically, it is known that each CDL component of the hydrocarbon gases has a fractional condensation temperature (FCT) that is a function of the partial pressure or vapor pressure of that compound in a mixture. Since effluent gases from the pyrolysis of coal produces a complex mixture of many compounds, each exerts only a fraction of the approximately 1 atm experienced in the system.  FIG. 3  illustrates the relationship between equilibrium vapor (or partial) pressure and temperature for twenty (20) of the most common condensable hydrocarbons present in effluent gases. Notably all are C 6  or larger and some are cyclic compounds. Curve M, for example, shows that m-Cresol at 1 atm should condense at about 200C, but at only 0.2 atm, would condense at about 140 C. Other compounds similarly have FCTs that are reduced from their BPs depending on their fractional concentration, as shown in  FIG. 3 . 
         [0054]    From the blending area, the coal char, coal fines, and particulates removed from the various CDL fraction may all be blended together to form fuel pellets or briquettes. In some embodiments, a portion of the heavy CDL fraction may optionally be used as a binder for the briquettes. Sludge  34  (with or without char fines) may also optionally be used as a binder for the briquettes. 
       EXAMPLE I 
       [0055]    A process and apparatus is set up substantially as schematically described in  FIG. 2  except no cyclone or venturi is used. Pyrolysis gas feed of 64,000 lbs/hr (29,030 kg/hr) is established with a breakdown as follows:
       15,000 lbs/hr (6,804 kg/hr) condensable components (CDLs);   22,000 lbs/hr (9,979 kg/hr) of a sweep gas used to heat the pyrolysis chamber as described in US2011/0011722 to Rinker;   27,000 lbs/hr (12,247 kg/hr) non-condensable or syngas component.       
 
         [0059]    This produces a condensable partial pressure of about 23.4% (15,000/64,000), i.e. approximately 25%. A three condensation zone absorber is arranged with heat exchange loops maintained at target temperatures of: 
         [0060]    about 495 F (257 C) for the heavy CDL fraction 
         [0061]    about 300 F (149 C) for the middle CDL fraction, and 
         [0062]    about 170 F (77 C) for the light CDL fraction. 
         [0063]    This configuration is designed to produce respective fractions of about 20% heavy, 25% middle and 55% light, with about 20% of the light being condensed in the exchange loop and an additional 35% recovered from an entrained mist in the air stream by an electrostatic precipitator in the gas cleaning area. 
       EXAMPLE II 
       [0064]    A process and apparatus substantially as schematically described in  FIG. 2  is set up. Seventeen process sampling points designated by Roman numerals from I to XVII are monitored and produce the data from Table B, below. A pyrolysis effluent gas feed of 41,813 kg/hr is delivered to a cyclone at about 473 C, which removes about 4655 kg/hr of particulates or about 11% by weight, leaving 37,158 kg/hr to flow into the absorber. Various fractions of CDLs (a combined total of 8,082 kg/hr) are removed at temperatures as shown in the Table B. Of this, about 24% is heavy CDL from zone A, about 30% is medium CDL from zone B, and about 25% from Zone C plus another 22% from the electrostatic precipitator totals about 47% light CDLs. This leaves about 27,409 kg/hr in non-condensable gases. The noncondensable gas stream is split, with approximately ⅔ (17,988 kg/hr) returning to the pyrolysis area as a sweep gas, and about ⅓ (9,424 kg/hr) being cooled to remove water and stored and/or supplied as a dried gaseous fuel. The characteristics of a gaseous fuel from a similar experiment with different flow rates are given in Table C below. Of course, the flow rates, volumes, capacities and the like are merely examples of the capabilities of the invention. Moreover, the gaseous fuel produced in this manner has a high heating value, for example in excess of 8000 BTU/lb. As seen from Table C, 124,000,000 BTU/hr divided by 15,044 lb/hr gives a fuel heating value of 8,241 BTU/lb (or 21.05 MJ/kg). 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE B 
               
               
                   
               
               
                 FRACTIONATING COMPONENTS FROM A PYROLYSIS GAS STREAM 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 I 
                 II 
                 III 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 Pyrolysis 
                 Pyrolysis 
                 Dust out 
                 IV 
                 V 
                 VI 
                 VII 
                 VIII 
                 IX 
                 X 
               
               
                   
                 Gas To 
                 Gas To 
                 from 
                 Gas into 
                 Heavy Oil 
                 Gas into 
                 Medium Oil 
                 Gas into 
                 Light Oil 
                 Gas into 
               
               
                   
                 Cyclone 
                 Venturi 
                 Cyclone 
                 Zone A 
                 Fraction Out 
                 Zone B 
                 Fraction Out 
                 Zone C 
                 Fraction Out 
                 ESP 
               
               
                   
               
               
                 T (° C.): 
                 473 
                 473 
                 473 
                 400 
                 273 
                 ~170 
                 150 
                 100 
                 72 
                 77 
               
               
                 Moisture: 
                 24% 
                 27% 
                   
                 27% 
                   
                 29% 
                 43% 
                 27% 
                   
                 30% 
               
               
                   
               
               
                 Flow: 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
               
               
                   
               
               
                 H 2   
                 172 
                 172 
                   
                 172 
                   
                 172 
                   
                 172 
                   
                 172 
               
               
                 CO 2   
                 8931 
                 8931 
                   
                 8931 
                   
                 8931 
                   
                 8931 
                   
                 8931 
               
               
                 H 2 O 
                 9990 
                 9990 
                   
                 9990 
                   
                 9990 
                 1250 
                 8740 
                   
                 8740 
               
               
                 CO 
                 2954 
                 2954 
                   
                 2954 
                   
                 2954 
                   
                 2954 
                   
                 2954 
               
               
                 CH 4   
                 2750 
                 2750 
                   
                 2750 
                   
                 2750 
                   
                 2750 
                   
                 2750 
               
               
                 C 2 H 6   
                 925 
                 925 
                   
                 925 
                   
                 925 
                   
                 925 
                   
                 925 
               
               
                 C 2 H 4   
                 281 
                 281 
                   
                 281 
                   
                 281 
                   
                 281 
                   
                 281 
               
               
                 C 3 H 8   
                 498 
                 498 
                   
                 498 
                   
                 498 
                   
                 498 
                   
                 498 
               
               
                 C 3 H 6   
                 415 
                 415 
                   
                 415 
                   
                 415 
                   
                 415 
                   
                 415 
               
               
                 C 4 H 10   
                 201 
                 201 
                   
                 201 
                   
                 201 
                   
                 201 
                   
                 201 
               
               
                 C 4 H 8   
                 313 
                 313 
                   
                 313 
                   
                 313 
                   
                 313 
                   
                 313 
               
               
                 C 4 H 6   
                 5 
                 5 
                   
                 5 
                   
                 5 
                   
                 5 
                   
                 5 
               
               
                 C 5 H 12   
                 148 
                 148 
                   
                 148 
                   
                 148 
                   
                 148 
                   
                 148 
               
               
                 C 5 H 10   
                 170 
                 170 
                   
                 170 
                   
                 170 
                   
                 170 
                   
                 170 
               
               
                 C 6   +   
                 848 
                 848 
                   
                 848 
                   
                 848 
                   
                 848 
                   
                 848 
               
               
                 S 
                 58 
                 58 
                   
                 58 
                   
                 58 
                   
                 58 
                   
                 58 
               
               
                 CARBON 
                 5072 
                 417 
                 4655 
                 417 
                 417 
                   
                   
                   
                   
                   
               
               
                 OIL 
                 8082 
                 8082 
                   
                 8082 
                 1975 
                 6207 
                 1675 
                 4532 
                 2406 
                 2126 
               
               
                 Total 
                 41,813 
                 37,158 
                 4655 
                 37,158 
                 2292 
                 34,866 
                 2925 
                 31,941 
                 2406 
                 29,535 
               
               
                   
               
             
          
           
               
                   
                   
                 XI 
                 XII 
                 XIII 
                 XIV 
                 XV 
                 XVI 
                 XVII 
               
               
                   
                   
                 ESP Oil 
                 Total Light Oil 
                 Total Wet Gas 
                 Sweep Gas 
                 Wet Gas to 
                 Condensed 
                 Net Dry 
               
               
                   
                   
                 Fraction Out 
                 Fraction Out 
                 From ESP 
                 to Pyrolysis 
                 Coder 
                 Water 
                 Gas 
               
               
                   
               
               
                   
                 T (° C.): 
                 77 
                 74 
                 77 
                 77 
                 77 
                 50 
                 60 
               
               
                   
                 Moisture: 
                   
                   
                 32% 
                 31% 
                 35% 
                 100% 
                 10% 
               
               
                   
               
               
                   
                 Flow: 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
                 kg/hr 
               
               
                   
               
               
                   
                 H 2   
                   
                   
                 172 
                 115 
                 57 
                   
                 57 
               
               
                   
                 CO 2   
                   
                   
                 8931 
                 5968 
                 2963 
                   
                 2963 
               
               
                   
                 H 2 O 
                   
                   
                 8740 
                 5488 
                 3255 
                 2600 
                 855 
               
               
                   
                 CO 
                   
                   
                 2954 
                 1980 
                 974 
                   
                 974 
               
               
                   
                 CH 4   
                   
                   
                 2750 
                 1840 
                 910 
                   
                 910 
               
               
                   
                 C 2 H 6   
                   
                   
                 925 
                 620 
                 305 
                   
                 305 
               
               
                   
                 C 2 H 4   
                   
                   
                 281 
                 190 
                 91 
                   
                 91 
               
               
                   
                 C 3 H 8   
                   
                   
                 498 
                 335 
                 163 
                   
                 163 
               
               
                   
                 C 3 H 6   
                   
                   
                 415 
                 280 
                 135 
                   
                 135 
               
               
                   
                 C 4 H 10   
                   
                   
                 201 
                 135 
                 66 
                   
                 66 
               
               
                   
                 C 4 H 8   
                   
                   
                 313 
                 210 
                 103 
                   
                 103 
               
               
                   
                 C 4 H 6   
                   
                   
                 5 
                 3 
                 2 
                   
                 2 
               
               
                   
                 C 5 H 12   
                   
                   
                 148 
                 100 
                 48 
                   
                 48 
               
               
                   
                 C 5 H 10   
                   
                   
                 170 
                 115 
                 55 
                   
                 55 
               
               
                   
                 C 6   +   
                   
                   
                 848 
                 570 
                 278 
                   
                 278 
               
               
                   
                 S 
                   
                   
                 58 
                 39 
                 19 
                   
                 19 
               
               
                   
                 CARBON 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 OIL 
                 2126 
                 4532 
                   
                   
                   
                   
                   
               
               
                   
                 Total 
                 2126 
                 4532 
                 27409 
                 17,968 
                 9424 
                 2600 
                 6824 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE C 
               
             
             
               
                   
               
               
                 GASEOUS FUEL CHARACTERISTICS 
               
             
          
           
               
                   
                 Composition 
                 Mass Flow 
                 Higher Heating Value 
               
             
          
           
               
                 Component: 
                 (Mass %) 
                 (lb/hr) 
                 (kg/hr) 
                 (Btu/lb) 
                 (MM BTU/hr) 
                 MW 
               
               
                   
               
             
          
           
               
                 Hydrogen 
                 H 2   
                 0.84% 
                 126 
                 57 
                 61,100 
                 7.68 
                 2.25 
               
               
                 Carbon Dioxide 
                 CO 2   
                 43.42%  
                 6532 
                 2963 
                   
                   
                   
               
               
                 Water Vapor 
                 H 2 O 
                 9.60% 
                 1444 
                 655 
                   
                   
                   
               
               
                 Carbon Monoxide 
                 CO 
                 14.27%  
                 2147 
                 974 
                 4,347 
                 9.33 
                 2.74 
               
               
                 Methane 
                 CH 4   
                 13.34%  
                 2006 
                 910 
                 23,879 
                 47.91 
                 14.04 
               
               
                 Ethane 
                 C 2 H 6   
                 4.47% 
                 672 
                 305 
                 22,320 
                 15.01 
                 4.40 
               
               
                 Ethylene 
                 C 2 H 4   
                 1.33% 
                 201 
                 91 
                 21,644 
                 4.34 
                 1.27 
               
               
                 Propane 
                 C 3 H 8   
                 2.39% 
                 359 
                 163 
                 21,661 
                 7.78 
                 2.28 
               
               
                 Propylene 
                 C 3 H 6   
                 1.98% 
                 298 
                 135 
                 21,041 
                 6.26 
                 1.84 
               
               
                 Butane 
                 C 4 H 10   
                 0.97% 
                 146 
                 66 
                 21,308 
                 3.10 
                 0.91 
               
               
                 Butene 
                 C 4 H 8   
                 1.51% 
                 227 
                 103 
                 20,840 
                 4.73 
                 1.39 
               
               
                 Butadiene 
                 C 4 H 6   
                 0.03% 
                 4 
                 2 
                 20,635 
                 0.09 
                 0.03 
               
               
                 Iso Pentane 
                 C 5 H 12   
                 0.70% 
                 106 
                 48 
                 21,052 
                 2.23 
                 0.65 
               
               
                 Pentene 
                 C 5 H 10   
                 0.81% 
                 121 
                 55 
                 20,712 
                 2.51 
                 0.74 
               
               
                   
                 C 6   +   
                 4.07% 
                 613 
                 278 
                 20,940 
                 12.83 
                 3.76 
               
               
                 Sulfur 
                 S 
                 0.28% 
                 42 
                 19 
                 3,983 
                 0.17 
                 0.05 
               
               
                 Total 
                   
                 100.0%  
                 15,044 
                 6824 
                   
                 124 
                 36 
               
               
                   
               
             
          
         
       
     
         [0065]    While the invention has been described with reference to various and preferred embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. 
         [0066]    Therefore, it is intended that the invention not be limited to the particular embodiment disclosed herein contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

Technology Classification (CPC): 2