WO1991003530A1 - Enrichissement accru de matieres carbonees - Google Patents

Enrichissement accru de matieres carbonees Download PDF

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Publication number
WO1991003530A1
WO1991003530A1 PCT/US1990/004848 US9004848W WO9103530A1 WO 1991003530 A1 WO1991003530 A1 WO 1991003530A1 US 9004848 W US9004848 W US 9004848W WO 9103530 A1 WO9103530 A1 WO 9103530A1
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Prior art keywords
solids
reactor
region
liquid
pressure
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PCT/US1990/004848
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English (en)
Inventor
George R. Nehls, Jr.
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Minnesota Power And Light
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Priority to AU63528/90A priority Critical patent/AU6352890A/en
Publication of WO1991003530A1 publication Critical patent/WO1991003530A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L9/00—Treating solid fuels to improve their combustion

Definitions

  • the present invention relates to an improved method and system for the beneficiation of carbonaceous materials.
  • the invention concerns processes and systems whereby carbonaceous solids, such as low rank coals and biomass, are treated so as to upgrade heating value, reduce moisture content, and improve handling characteristics.
  • Carbonaceous materials such as low rank coals and biomass, e.g., peat and cattails, may be used as a substitute source of energy for high grade coals. They often contain less sulfur than many of the deposits of high rank coals and are generally more readily obtainable. These materials, however, generally contain more water and provide less energy (per unit weight) than do high rank coals.
  • Low rank or low grade carbonaceous materials or coals include lignite, brown coal, and subbituminous coal. Such carbonaceous low grade coals are characterized in that they have not undergone sufficient geological metamorphosis to be converted into high grade hard coals such as bituminous or anthracite. Coal is a naturally occurring solid material that is an aggregate of undifferentiated hydrocarbonaceous solids (at room temperature), oxygen, water, and a wide assortment of inorganic minerals. Because the properties of coal vary widely between each naturally occurring deposit, attempts have been made to define broad classifications which group coal into a more coherent structure.
  • quality can be interpreted to mean an increasing proportion of hydrocarbonaceous, i.e., carbonaceous, material per unit amount of coal.
  • increasing quality can also mean a decreasing proportion of the detritus, e.g., oxygen, water, and mineral content in the coal.
  • a relatively large coal deposit stretches north across the states of Wyoming and Montana. This is often referred to as the Powder River Basin deposit.
  • a Powder River Basin coal generally describes a subbituminous coal with relatively low sulfur content and relatively high moisture content.
  • a specific coal seam within the Powder River Basin such as Rosebud, defines a coal with the general characteristics of a Powder River Basin coal, but differing somewhat in specifics. In this case.
  • Rosebud coal has a somewhat higher sulfur content and a mineral content specific to the Rosebud seam within the Powder River Basin.
  • carbonaceous materials may be classified according to their heating value.
  • High rank coals are generally considered to be those coals that possess a heating value of greater than about 10,000 BTUs/pound, whereas the heating value of low rank coals is generally less than this value.
  • the heating value, or the "power" per unit weight, of bituminous coals is around 11,000 BTUs/pound and that of lignite is around 7,000 BTUs/pound.
  • Low rank coals often contain about 30% to 70% by weight moisture (H 2 0) as mined. They also often contain up to about 20% by weight oxygen, excluding the a ount contained in the H 2 0.
  • This oxygen is generally contained in nondecomposed organic detritus, and is typically in the form of carboxyl (-COOH) groups present in residual acids, such as humic acids, as well as sodium carboxylate (-COONa) and perhaps other metal caroxylates (-COOM), that may be present. That is, the oxygen content found in most low rank coals and peat (exclusive of that within the 30% to 70% moisture) results from the partial decomposition of products of organic matter. Biomass often contains an even higher moisture and oxygen content. Both water and oxygen are generally undesirable, at least in part because they represent weighty impurities. Furthermore, the oxygen content present in the -C00H and -COONa groups can make the material relatively reactive, which is not always desirable.
  • Some of the known hot water or steam treatment processes involve the use of batch autoclaves at elevated temperatures with pressures greater than the vapor pressure of water at such temperatures.
  • Other systems use rotary preheating and processing kilns.
  • Hydraulic lockhopper arrangements are known and used for both feeding coal into, and discharging beneficiated coal from, such systems. These allow for the transfer of the material between ambient pressure and the reactor pressure. In certain reactor systems the feeding and discharging systems also incorporate means for draining or dewatering the coal.
  • pumpable slurry systems are used for the dewatering of relatively fine particle size coal or biomass.
  • the relatively fine solid particles i.e., with a particle size of less than about 1/4 inch (6 mm)
  • the slurry is then passed through a heat exchanger for treatment.
  • pressurized oxygen or oxygen-containing gases are introduced to enhance the oxidation of organic matter therein. This serves as a source of heat for the dewatering process.
  • chemical additives during the thermal treatment of carbonaceous materials. For example, nonaqueous volatile solvents have been added to moist particulate carbonaceous material to displace the water.
  • Certain of these systems are limited in the minimum particle size and density of the material that can be processed. Very small particles often create problems associated with, for example, plugging of certain systems. Also, materials close in density to that of water limit certain beneficiating systems to the use of less dense organic liquids, particularly in countercurrent extraction systems.
  • What is needed is a more efficient beneficiation method that improves the fuel properties of a wide variety of carbonaceous solids, such as low rank coals and biomass.
  • What is particularly needed is a system which is well adapted to handle not only solids comprising large particles, but also those solids containing materials of relatively low density and relatively small particle size.
  • e ethod is needed that more efficiently reduces the moisture, oxygen, and sodium content of carbonaceous materials, thereby upgrading the heating value of the material while improving the mechanical handling and combustion properties of the solids.
  • Such improvements could at least in part lie in an achieved reduction in the amount of resources required to operate the process. These resources may include, but are not limited to, water, energy, and financial resources.
  • the methods and systems of the present invention utilize a thermochemical process of hydrothermal reforming, also known as wet carbonization or hot-water drying, for beneficiating, i.e., treating so as to improve the useful properties of, carbonaceous solids.
  • the hydrothermal reforming process can be characterized in that it may be used to: reduce the surface and inherent water content of the solids (typically) by up to about 30%; and reduce the oxygen content by typically up to about 30%, and possibly by up to about 50%.
  • the reduction in the water and oxygen content of the carbonaceous material results in chemical upgrading, improvement in the heating value, and improvement in the handling characteristics of the solids material.
  • the carbonaceous material is physically reformed to a state that is permanently less retentive of water.
  • the preferred process results in a reduction of the sodium content of the carbonaceous material typically by about 75% to 90%, depending upon the material and the peak processing temperature.
  • the natural sodium content of carbonaceous solids which may be almost negligible for some low rank coals, but which is typically within the range of about 1% to 1.5% by weight for certain coals, has caused some problems in the combustion of such materials due at least in part to ash fouling.
  • reduction in sodium content is advantageous for certain low rank coals.
  • carboxylic -C00H (carboxyl) and -COONa (sodium carboxylate) groups break down and release carbon dioxide gas.
  • the carbon dioxide (C0 2 ) gas it is believed, forces liquid water out of interior pores and orifices in the material, where such water may have been trapped.
  • the process is further believed to result in a reduction in the size of these internal pores and orifices, which may contribute to the observation that the water is not generally reabsorbed by the treated solids, even if the solids are kept immersed in water and under relatively high pressure (at approximately 2300 psi, i.e., 156 atm) .
  • reduction in the number of carboxyl groups may be a contributing factor to the observation that the sodium content is reduced.
  • Applications of the systems and methods of the present invention also preferably include oil agglomeration and low temperature drying in conjunction with hydrothermal reforming.
  • Such processes transform, for example, low rank coals, such as subbituminous and lignite, from marginal quality fuels to higher quality, reduced sulfur, fuels.
  • low rank coals such as subbituminous and lignite
  • the sulfur content of materials such as low rank coals is normally relatively low (about 0.5% to 2%) to start with, the overall process described herein that includes both hydrothermal reforming and oil agglomeration generally results in a reduced sulfur content to advantage.
  • the additional processing steps described, beyond the hydrothermal reforming process itself can further reduce the water content of the solids by up to about 80% total. The net result is an economical fuel with improved heating value, desirable combustion characteristicr and improved transportation quality.
  • thermochemical beneficiation of carbonaceous solids is described by P.B. Tarman et al. in U.S. Patent No. 4,579,562, the disclosure of which is incorporated herein by reference.
  • This system uses a pressurized countercurrent extraction reactor.
  • the process introduces carbonaceous solids, between about 1/4 inch (6 mm) to 4 inches (10 cm) in diameter, and substantially free of surface liquids into the upper portion of the reactor. These solids move in a countercurrent flow to a process liquid that flushes the product liquid containing dissolved and suspended organic material, which is released from the carbonaceous solids.
  • the beneficiated solids are then removed from the lower portion of the reactor.
  • the product liquid is removed from the upper portion of the reactor and is directed to a water treatment facility.
  • the systems and methods of beneficiating carbonaceous solids according to the present invention utilizes a unique and improved reactor arrangement for hydrothermal reforming, with a reactor vessel adapted to confine a downwardly moving bed of carbonaceous solids and a countercurrent flow of process liquid.
  • the reactor vessel of the present invention because of certain improvements discussed in detail below, can advantageously be used to beneficiate a wide variety of low rank coals and other carbonaceous solids.
  • carbonaceous solids including a substantial fraction of material with a particle size of less than about 1/4 inch (6 mm), as well as solids including a substantial fraction with a particle size of up to about 4 inches (10 cm) are relatively efficiently and/or effectively beneficiated using the preferred systems and methods of the present invention.
  • a carbonaceous material with at least about 5% to 10% with a particle size of less than about 1/4 inch, and more typically with at least about 50% with a particle size of less than about 1/4 inch can be advantageously beneficiated using the preferred systems and methods of the present invention.
  • a carbonaceous material with at least about 5% to 10% with a particle size of up to about 4 inches, and more typically with at least about 50% with a particle size of up to about 4 inches can be advantageously beneficiated using the preferred systems and methods of the present invention.
  • the reactor arrangement of the present invention possesses many other improvements and advantages over known systems, as will become apparent in the following discussions.
  • a lower countercurrent reactor region Within a preferred reactor vessel of the reactor arrangement according to the present invention, is a lower countercurrent reactor region, a freestanding liquid region and means for defining each.
  • the freestanding liquid region is located generally above the lower countercurrent reactor region and is in fluid flow communication therewith.
  • a retained solids region within a preferred reactor vessel there is a retained solids region, and means for defining such, oriented above the lower countercurrent reactor region and in solids flow communication therewith.
  • Each of the retained solids region and the freestanding liquid region provides advantages to the operation of the reactor vessel. When in combination in a preferred embodiment additional advantages are realized. Certain of these advantages will become apparent through the following discussions.
  • the retained solids region is separated from the freestanding liquid region by suitable means (although in some applications direct fluid flow therebetween is permissible) .
  • the retained solids region is preferably defined, at least in part, by a retaining structure, which in a preferred embodiment has a somewhat annular configuration such as a ring or funnel shape, of which at least a portion defines an internal volume and has an external surface.
  • the external surface of the retaining structure in a preferred embodiment, completely circumscribes the internal retaining volume, and thus the retained solids region, and in part defines the freestanding liquid region.
  • the freestanding liquid preferably circumscribes at least a portion of the external surface of the retaining structure.
  • the freestanding liquid region circumscribes at least a portion of the carbonaceous solids retained by said structure. More preferably, the freestanding liquid region completely circumscribes a portion of the external surface of the retaining structure.
  • the retaining structure may be mounted in the reactor vessel in any of a variety of manners.
  • the retaining structure may be mounted on an internal sidewall of the reactor vessel or it may include a cylindrical or funnel (or similar) extension depending from an upper portion of said internal sidewall, or from a top wall, of the reactor vessel.
  • the reactor vessel advantageously and preferably incorporates a fluid flow arrangement, which includes an outlet arrangement in fluid flow communication with the freestanding liquid region.
  • the fluid flow arrangement also includes an inlet, for selectively providing, i.e., directing, fluid flow into the lower countercurrent reactor region.
  • the fluid flow arrangement preferably includes means for directing fluid flow from the inlet arrangement through the lower countercurrent reactor region into the freestanding liquid region, and from the freestanding liquid region to the fluid flow outlet arrangement.
  • at least a portion of the process liquid is directed into the freestanding liquid region, which circumscribes at least a portion of the carbonaceous solids. From this freestanding liquid region at least a portion of the fluid is preferably directed into the fluid flow outlet arrangement.
  • At least a portion of the process liquid is then directed from the reactor fluid outlet arrangement to the reactor fluid inlet arrangement (i.e., recycled).
  • the process liquid is preferably directed through a recirculation heat exchange system.
  • a secondary heat supply system may be used in a preferred embodiment for maintaining an effective temperature in the reactor.
  • At least a portion of the process liquid is directed from the freestanding liquid region through the fluid flow outlet arrangement to feeding means for feeding carbonaceous solids, i.e., a solids feed system, which charges the reactor with the carbonaceous solids and is further discussed below.
  • a solids feed system which charges the reactor with the carbonaceous solids and is further discussed below.
  • the process liquid both pressurizes the system and heats the solid material somewhat before it is charged into the reactor.
  • the system of the present invention utilizes a method whereby process liquid is extracted from the upper countercurrent reactor region and is directed to the solids feed system. Because the extracted process liquid is used to charge the solids feed system, preferred systems and methods reduce the amount of extraneous liquid introduced into the process.
  • the solids feed system of a preferred embodiment provides means for selectively and substantially continuously feeding carbonaceous solids into the reactor, specifically into the internal volume of the retaining structure, i.e., the retained solids region, of the reactor vessel.
  • a preferred such system includes a plurality of feed lockhoppers, e.g., hydraulic lockhoppers, for feeding the solids directly into the reactor vessel.
  • process liquid extracted from the upper portion of the reactor is preferably used at least in part to pressurize the feed lockhoppers.
  • the solids feed system of a more preferred embodiment provides a lockhopper, or series of lockhoppers, each of which is capable of intermittently feeding solids into the reactor, which is operated at a pressure of at least a first operating pressure.
  • Each of the lockhoppers includes a storage receptacle, means for delivering feed solids into the storage receptacle at a second pressure, which is lower than the first operating pressure, and means for delivering feed solids from the storage receptacle into the reactor at an operating pressure thereof. It is to be understood that the pressure of the reactor vessel can vary from that of the first operating pressure, and that typically this second pressure is atmospheric pressure.
  • Each of the lockhoppers also includes means for venting gas from the storage receptacle and means for pressurizing the storage receptacle from the second pressure at least up to the first operating pressure with liquid.
  • the lockhopper is thereby designed for pressurization as a hydraulic lockhopper and depressurization as a gas-filled lockhopper.
  • shunt means is provided by which process gas flow is directed into a process gas receiving region, which is oriented above the freestanding liquid region.
  • This process gas flow is preferably directed from a location in the submerged solids portion of the downwardly moving bed of carbonaceous solids in the lower countercurrent reactor region, which may generally be divided into a solids preheat zone, a hydrothermal reaction zone, and a liquid preheat zone (i.e., an upper, middle, and lower portion) .
  • the preferred shunt means includes at least one gas flow tube having a first end oriented in the process gas receiving region, and a second end, preferably with means to inhibit transfer of larger particles therethrough, oriented in the lower countercurrent reactor region.
  • the second end is oriented in the portion of the lowe countercurrent reactor somewhat above the region in which the solids are beneficiated, i.e., above the hydrothermal reforming reaction zone, in the solids preheat zone.
  • the gas flow tube allows at least some of the process gases to be diverted directly into the process gas receiving region. By this it is meant that some of the process gases are funneled, i.e., shunted, out of the lower reactor region through a tube. In this way the process gases are less likely to disturb the countercurrent flow of process liquid and carbonaceous solids.
  • the diverted process gases are then preferably discharged from the process gas receiving region through outlet means, e.g., a vent arrangement.
  • the process gases may then be directed to the feed lockhoppers or the solids discharging system, if desired, for advantageous operation of these systems.
  • the preferred reactor arrangement also includes means whereby the carbonaceous solids are selectively and substantially continuously discharged from the downwardly moving bed of carbonaceous solids using conveying means for transferring the solids under pressure from the reactor vessel.
  • the discharge of the carbonaceous solids is preferably from the lower portion of the lower countercurrent reactor region.
  • the conveying means may include at least one screw conveyor.
  • the screw conveyor(s) may be sufficiently long and narrow in cross section to allow direct discharge of the carbonaceous solids to ambient pressure.
  • the conveying means may also include a hollow-shafted auger(s) for providing advantageous discharge of the beneficiated solids.
  • the screw conveyor(s) discharges the solids into a hydraulic lockhopper while under pressure. For added advantage a plurality of hydraulic lockhoppers are used for substantially continuous discharge.
  • Figure 2 is flow chart of a preferred hydrothermal reforming process involving methods according to the present invention.
  • Figure 3 is a flow chart of an overall process involving selected methods of hydrothermal reforming, oil agglomeration, and low temperature drying according to the present invention.
  • Figure 4 is a schematic drawing of a reactor vessel (containing a funnel-shaped retaining structure patterned after a cross-sectional view) for use in application of the present invention.
  • Figure 5 is a schematic drawing of a reactor arrangement including a reactor vessel and solids feeding means according to the present invention.
  • Figure 6 is a schematic drawing of a screw conveyor extraction arrangement for solids discharge.
  • Figure 7 is a schematic drawing of an alternate embodiment of a screw conveyor extraction arrangement for solids discharge.
  • Figure 8 is a schematic drawing of a hollow extraction auger arrangement for solids discharge.
  • Figure 9A is a flow chart of a portion of an overall process involving selected methods of the present invention used for upgrading certain lignite material (see Example I) .
  • Figure 9B is a flow chart of follow-up steps to the process described by Figure 9A.
  • Figure 10 is a schematic drawing of a solids feed system.
  • Figure 11 is a schematic drawing of a solids feed system according to Figure 10 shown in the lockhopper charging stage of operation.
  • Figure 12 is a schematic drawing of a solids feed system according to Figure 10 shown in the lockhopper discharging, i.e., reactor charging, stage of operation.
  • Hydrothermal reforming processes typically reduce the surface and inherent water by up to about 30%. (Further processing steps following the hydrothermal reforming process aid in reducing the water content by up to about 80% total.) Furthermore, the conversion of surface carboxyl and sodium carboxylate and/or other metal carboxylate groups to gaseous C0 2 contributes to t .e reduction in the oxygen content by typically up to about 30%, and possibly by up to about 50%.
  • the intent is to refer to oxygen groups in the coal (for example, carboxylate groups). No reference to oxygen in water is meant.
  • the reduction in the moisture and oxygen content results in, for example, the chemical upgrading of the solids, improvement in the heating value of the energy resource, and improvement in the handling characteristics of the material. Additionally, such processes result in a reduction of the sodium content to advantage.
  • the sodium content may be reduced by up to about 75% to 90%.
  • North Dakota lignite characteristically has a heating value of 6,800 BTUs/pound, contains 47% hydrocarbons (fuel), 34% moisture, 12% oxygen, and 7% ash.
  • the percentage of hydrocarbons herein refers to the percentage of carbon and hydrogen, whereas oxygen is reported as a separate percentage, i.e., the oxygen content is not included in what is referred to as hydrocarbon content.
  • the ash is typically high in sodium content (about 2% to 10%), which can create severe boiler fouling problems.
  • the ash is also typically high in minerals, especially silica, and is often represented simply as Si0 2 for purposes of mass flow analysis.
  • This material can be transformed by the system and method of the present invention to an economical, higher quality fuel.
  • the processed fuel will have a nominal heating value of 10,900 BTUs/pound, 68% hydrocarbons (fuel), 9.5% moisture, 14% oxygen, and 8.5% ash.
  • the sodium content of the ash will have been reduced to about 1% to 2%.
  • Such material will exhibit excellent combustion characteristics.
  • the sulfur content of the fuel will have been reduced to about 1.5 pounds S0 2 /MMBTU.
  • the processed fuel generally will exhibit little or no tendency to self-ignite, and will have substantially reduced dusting and crumbling tendencies.
  • the carbon dioxide gas is believed to play a role in removing the liberated liquid water by forcing the water out of interior pores and orifices, where it may be trapped.
  • the sodium content is generally reduced by this process, probably due, at least in part, to reduction in the number of carboxyl groups.
  • a product that has gone through a hydrothermal reforming process has a permanently transformed, or reformed, structure with a reduced capacity to retain water therein. Although it is stated above that this process reduces the moisture content of typical carbonaceous solids, such as low rank coals, by typically up to about 30%, the moisture content of the coal product exiting the reactor is typically higher than the "equilibrium" moisture content of the coal product.
  • a preferred system and method of beneficiating carbonaceous solids according to the present invention utilizes a hydrothermal (hot water) reforming process as outlined in the flow chart in Figure 2.
  • carbonaceous solids are fed into a reactor wherein, at 2, heat exchange and the hydrothermal reforming reaction occurs.
  • the system and method involve a downwardly moving bed of carbonaceous solids and a countercurrent flow of process liquid for countercurrent extraction and energy exchange.
  • the process liquid is fed into the reactor, at 3, below the level at which the reformation occurs, and is withdrawn from the reactor, at 4, above the level of the submerged downwardly moving bed of solids.
  • This process liquid is preferably recycled and directed back into the reactor for further processing of solids (see path 5).
  • At least a portion of the extracted process liquid may also be used in the process of charging, or feeding, the reactor with the solids (refer to the description at 6) .
  • liquid is extracted from the process at a rate more or less equal to the rate at which moisture is extracted from the coal. This is done to maintain an appropriate liquid level in the reactor. This extracted process liquid is directed out of the process at 6', for example, to waste water treatment.
  • the beneficiated carbonaceous solids are discharged from the reactor by suitable means (see reference numeral 7) .
  • Preferred ones are those capable of removing the solids from the reactor without a need for significant reduction of pressure within the reactor.
  • the hydrothermal reformation process typically results in the production of gases, such as C0 2 , which are preferably directed, or shunted (at 8), directly into a process gas receiving region of the reactor, located above the solids and liquid level. These gases may also be withdrawn from the reactor, at 9, and be optionally used in the process of feeding the solids into the reactor, at 10, or discharging the solids from the reactor, at 11, or completely withdrawn from the reactor.
  • An overall preferred application of the beneficiation process of the present invention encompasses the hydrothermal reforming process outlined in Figure 2, an oil agglomeration process, and low temperature drying (see Figure 3).
  • a carbonaceous solid such as lignite is transported from the mine to a processing plant 12 where it is crushed.
  • the crushed coal is then transported to the hydrothermal reforming vessel(s) 13, i.e., the reactor vessel(s).
  • the beneficiated product is screened, at 14, to split the coal into two general groups according to size. That is, product sizing occurs at 14.
  • the coarse product typically consists of particles greater than.about 1/8 inch (3 mm) as the smallest dimension, and the fine product consists of particles less than about this particle size.
  • the fines undergo selective oil agglomeration, at 15, which reduces the amount of pyrites and ash contained therein.
  • the fine product i.e., fine fraction
  • the coarse particles directly undergo low temperature drying, at 16.
  • the final product is then stored also at 16.
  • a treatment facility 17 i.e., a waste water treatment facility, for process liquid used in the hydrothermal reforming vessel 13 and liquid removed in the drying operation at 16, and later discharged as a liquid by-product.
  • Selective oil agglomeration involves the mixing of relatively fine coal particles in a water-based slurry. Under high shear mixing a small portion o-. oil is then added to the slurry. The fine coal particles tend to agglomerate into larger particles. Detritus, such as ash and pyrites, that have become liberated, i.e., no longer adhere to the coal particles, do not then typically re-attach to the coal/oil agglomerates. It is noted that, although the portion of coal that is defined as "fines" will vary according to coal, processing conditions, and desired product, a typical proportion of fines is about 25% of the total coal mass flow that has been previously processed by hydrothermal reformation.
  • the conditions of the countercurrent reformation reaction process for beneficiating carbonaceous solids vary depending upon the type of material. Generally, however, the hydrothermal reforming reaction operates at a peak temperature of about 450°F to 630°F (230°C to 330°C) .
  • the pressure within the reactor used for this reaction should be sufficient to prevent vaporization of the process liquid (typically water) at these temperatures. Operating pressures used in processes and reactors of this type generally range from about 300 to about 2300 psi (about 20 to 156 atm) .
  • the desired pressure usually depends upon the density of the solids in the moving bed, and is generally maintained at about 30 to 70 psi (about 2 to 5 atm), and preferably about 45 to 55 psi (about 3 to 4 atm) , above the saturation vapor pressure of the liquid at the peak temperature of the reaction.
  • the flow rate of the solids in the downwardly moving bed is adjusted such that a sufficient residence time is maintained to achieve effective beneficiation, i.e., reforming. This varies depending upon the type of material and the particle size of the material. Generally, for materials such as low rank coal with a maximum particle size of about 4 inches (10 cm), the flow rate necessary to accomplish effective beneficiation is such that the residence time is about 40 to 80 minutes, and preferably about 60 minutes.
  • the residence time is generally about 30 minutes.
  • the rate of the countercurrent flow of process liquid is also adjusted such that the carbonaceous solids are effectively beneficiated and the by-products of the process are effectively removed.
  • the reactor arrangement of the present invention incorporates means to relatively effectively and efficiently reduce the problems associated with beneficiating solids including materials with fractions of relatively small particle size and/or relatively low density by preferably using water as the process liquid, and by reducing the amount of entrained solids in process liquid that is extracted from the reactor arrangement.
  • This representation it is not meant that the entrainment of solids in the liquid extraction process is completely eliminated by the present invention, or that filtration systems cannot be used in addition, to advantage. Rather, the size and amount of solids that do become entrained in the extracted liquid are advantageously reduced.
  • FIG 4 is a schematic of a hydrothermal reforming reactor or reactor vessel 20 of the present invention.
  • the reactor vessel 20 may correspond to the reactor 13 in Figure 3.
  • the reactor vessel 20 is adapted to confine a downwardly moving (moving in the direction of arrow 21) bed of carbonaceous solids 22 and a countercurrent flow (moving in the direction of arrow 23) of process liquids 24. That is, the material to be beneficiated flows downwardly through the reactor vessel 20 as a packed bed of-solids 22 countercurrent to the liquid 24, typically water, that flows upwardly through the reactor vessel 20.
  • the reactor vessel 20 includes an internal side wall 25 for defining, at least in part, a lower countercurrent reactor volume or region 26.
  • the lower countercurrent reactor region 26 can be viewed as including three general regions consisting of: a (central) hydrothermal reforming reaction zone 28; an (upper) solids preheat zone 29 (which is a volume of direct countercurrent heat exchange); and, a (lower) liquid preheat zone 30 (which is also a volume of direct countercurrent heat exchange).
  • a (central) hydrothermal reforming reaction zone 28 which is a volume of direct countercurrent heat exchange
  • a (lower) liquid preheat zone 30 which is also a volume of direct countercurrent heat exchange.
  • the hydrothermal reforming reaction zone 28 which is where the majority of the hydrocarbon reforming reactions typically occur, is generally in the middle portion 32.
  • the reaction zone 28 is merely that region in which both the liquid and the solids are at an appropriate temperature for beneficiation reactions to efficiently occur.
  • the reactor vessel 20 further includes a retaining structure 40 defining an internal volume 41.
  • the structure 40 of the embodiment shown includes an outer wall 42 defining; an upper extension or funnel portion 43; a lower ring 43'; an external surface 44; and, a bottom edge 45.
  • the retaining structure 40 defines a retained solids region 46 above the lower countercurrent reactor region 26 and in solids flow communication therewith.
  • the bottom edge 45 of the retaining structure outer wall 42 generally defines a "boundary" in the reactor 20 between the lower countercurrent reactor region 26 and an upper countercurrent reactor region 48. It is not meant, however, that there is a physical boundary or separation between the two regions 26 and 48. There is indeed fluid flow and solids flow therebetween. The distinction has been made for ease of description.
  • the retained solids region 46 is thus located in the upper countercurrent reactor region 48 and is generally the portion of the reactor vessel 20 into which the carbonaceous solids are initially introduced.
  • a portion of the downwardly moving bed of solids 22 is retained by the retaining structure 40 in the sense that the solids are retained, or confined, to a space of smaller cross- sectional area (i.e., a region with a smaller cross- sectional diameter if the retaining structure ring 43' is annular) than that of the reactor vessel 20.
  • This configuration allows for a freestanding liquid region
  • the freestanding liquid region 50 is defined by the external retaining surface 44, at a location generally above the lower countercurrent reactor region 26 and in fluid flow communication therewith. It is noted that at least a portion of the freestanding liquid region 50 may be within what is defined as the lower countercurrent reactor region 26.
  • the retaining structure 40 generally separates the retained solids region 46 from the freestanding liquid region 50 at least with respect to any substantial direct solids flow therebetween.
  • the retaining structure 40 may allow direct fluid flow communication between the regions 46 and 50. That is, during operation, the retaining structure 40 generally segregates a portion of the process liquid 24 in the upper countercurrent reactor region 48 from the downwardly moving bed of carbonaceous solids 22. This creates a region 50 in which a portion of the liquid 24 will be generally free of the solids bed 22. This advantageously provides a generally solids-free liquid for extraction (and, if desired, recycling for use elsewhere in the reactor), and process control.
  • the bed of carbonaceous solids 22 moves downwardly countercurrent to the upwardly moving process liquid 24 in the lower countercurrent reactor region 26.
  • the process liquid 24 may be any liquid that can be heated to the desired hydrothermal reforming temperatures which result in the effective beneficiation of the desired carbonaceous solids 22.
  • the process liquid 24 is water.
  • the process liquid 24 is preferably introduced under pressure by pump means, such as pump 52 in conjunction with a valve arrangement 53 for directing process liquid to solids discharge means (which operates through opening 54 and is discussed in further detail below) , into the lower portion 33 of the lower countercurrent reactor region 26 at or near a base 55 of the reactor vessel 20 through a fluid flow inlet arrangement 60, which for the embodiment shown comprises: a fluid flow inlet port 62; a fluid flow inlet conduit 64; and a fluid flow inlet control valve 66.
  • the process liquid 24 is withdrawn from the reactor vessel 20 via a fluid flow outlet arrangement 70, which for the embodiment shown comprises: a fluid flow outlet port 72; a fluid flow outlet conduit 74; and a fluid flow outlet control valve 76.
  • the fluid flow of the process liquid 24 is directed from the fluid flow inlet arrangement 60 through the lower countercurrent reactor region 26 into the freestanding liquid region 50 and preferably from the freestanding liquid region 50 to the fluid flow outlet arrangement 70.
  • the rate that the process liquid 24 is introduced into the reactor vessel 20 may be controlled by the fluid flow inlet control valve 66.
  • Also near the base 55 of the reactor is means for steam input 77 for a source of thermal energy.
  • an overflow drain orifice 78 is provided in the reactor vessel 20, and location above outlet port 72. As a result, should the liquid level surge during operation, an overflow is provided. Flow under pressure from the overflow drain orifice 78 may be directed into waste water treatment, or the like, Figure 5. For the arrangement shown in Figure 4, a plurality of overflow drains 78 are shown.
  • the retaining structure 40 defines external surface 44. Also, for the preferred embodiment shown, the external surface 44 completely circumscribes the internal retaining volume 41.
  • the ring portion 43' of retaining structure 40 mirrors the shape of the reaction vessel.
  • the ring portion 43' of retaining structure 40 has an annular or circular configuration, since the preferred reactor 20 is circular in cross-section. It is to be understood, however, that alternate configurations of the retaining structure 40 are possible.
  • the ring portion 43' of retaining structure 40 may be square-shaped in some applications.
  • the wall 42 of the retaining structure 40 is angled upward and outward, i.e., flared, such that the upper extension 43 extends up to or near the internal top wall 80, i.e., towards the upper portion of the internal sidewall 25, of the reactor vessel 20. This inhibits spilling of solids into the freestanding liquids zone 50. Apertures 81 in the upper extension 43 allow for pressure equilibration between portions of the reactor 20.
  • a retaining structure 40 installed within the reactor vessel 20 allows for the establishment of a retained solids region 46 of the densely packed, downwardly migrating bed of carbonaceous solids 22.
  • the retained solids region 46 is smaller in cross- sectional diameter than the reactor vessel 20.
  • the angle of repose also known as the angle of rest, can be defined as "the maximum slope at which a heap of any loose or fragmented solid material will stand without sliding, or will come to rest when poured or dumped in a pile or on a slope" (McGraw-Hill Dictionary of Scientific and Technical Terms: D. W. Lapedes, Ed.; 1974, p. 68). Solids are known to adopt a characteristic angle of repose, both when dry and when wet, depending upon the type and particle size of the solids. Thus, it is understood that region 50 is formed (above the solids angle of repose) into which the process liquid 24 may flow and be generally segregated from the downwardly moving bed of solids 22.
  • freestanding liquid 83 in the region 50 will be in direct contact with the submerged solids 84.
  • the downwardly moving bed of carbonaceous solids 22 herein are referred to as the retained solids 85.
  • the retained solids 85 This is also meant to include any solids that rest upon those within the internal volume 41 and extend along the upper extension 43 of the retaining structure wall 42, or which are piled up within volume 88.
  • the downwardly moving bed of solids 22 is herein referred to as the submerged solids 84.
  • the freestanding liquid region 50 is defined by the reactor internal side wall 25, the external surface 44 of the retaining structure 40, and the submerged solids 84, which reside at their wet angle of repose 82.
  • the process liquid 24 within the freestanding liquid region 50 is referred to as the freestanding liquid 83 with a surface or upper level 89.
  • the retained solids region 46 extends above the upper level 89 of the freestanding liquid 83 (and similarly, above the upper surface 90 of the process liquid 24 within the retaining structure 40) .
  • the weight of the retained solids 85 provides a downward pressure on the densely packed submerged solids 84.
  • This provides an improvement in performance over other countercurrent reactors, in which a retained solids region 46, as defined by a retaining structure 40, is not present.
  • solids of relatively low density e.g., those that are close in density to that of water, do not migrate downward readily and effectively in a countercurrent manner to the upward flow of water. Therefore, generally less dense liquids and/or relatively low flow rates are necessary to produce an effective countercurrent flow for such solids.
  • the arrangement of the present reactor permits the use of process liquids, or fluids, that are closer in density to that of the solids (or vice versa) .
  • Fine carbonaceous solids such as biomass
  • the allowable upward flow velocity for the process liquid 24 can be increased since the downward pressure of the retained solids 85, enhanced from the presence of solids piled above the liquid upper surface 90 within the retaining structure 40, can counteract the liquid flow. This allows for more efficient, economical, and effective beneficiation of carbonaceous materials in general, and especially for those materials with a significant percentage of relatively fine particles.
  • the creation of a region 50 of freestanding liquid 83 is advantageous.
  • the creation of a region of liquid (for liquid takeoff) which is isolated from solids feed, especially larger particle size solids, provides a liquid that may be relatively effectively extracted. This liquid would thus have reduced need for further separation of the solids entrained in the liquid, as compared to conventional reactors in which there is no freestanding liquid region.
  • the generation of this freestanding liquid region 50 gives solid particles entrained (or suspended) in the process liquid 24 entering the region 50 (along the direction of arrow 23) a greater chance to settle.
  • the solids settling will be facilitated because there will be less turbulence in the area around the fluid flow outlet arrangement 70, compared to conventional reactors. This is because, at least in part, introduced feed solids 51 will generally not be directed into the freestanding liquid region 50. Also, as the process liquid flows from the lower countercurrent reactor region 26 into the freestanding liquid region 50, overall flow rate effectively drops, allowing some settling. Entrainment of solids in liquid flow depends upon such factors as the viscosity and density of the fluid, the particle density, the particle effective surface area, and the flow velocity of the fluid relative to the particle.
  • carbonaceous solids such as biomass, including fractions, e.g., up to about 50%, with a relatively small particle size, as for example less than about 1/4 inch (6 mm)
  • a relatively small particle size as for example less than about 1/4 inch (6 mm)
  • the reactor vessel 20, with its retaining structure 40 provides an enhanced downward flow of relatively low density and small particle solids due to the downward force of the retained solids 85.
  • water is not required to be used by the present method and system, it is preferred, and may be used with solids possessing a density close to that of water because of this enhanced countercurrent flow.
  • the retaining structure 40 may be affixed to the reactor vessel's internal side wall 25 by any suitable mounting means.
  • the mounting means or arrangement 91 shown in the preferred embodiment of Figure 4 comprises welding struts 92.
  • An alternate embodi ent would be to affix the retaining structure 40 to the reactor vessel's internal top wall 80 by hanging welding struts (not shown in Figure 4) .
  • the internal volume 41 circumscribed by the retaining structure wall 42 should be provided generally clear of obstruction, so that the introduced feed solids 51 may be readily fed into the lower countercurrent reactor region 26 therethrough (i.e., outwardly from the bottom edge 45).
  • a preferred reactor arrangement of the present invention provides an improved extraction system and method, at least in part, because of a reduction in the amount of suspended solids extracted therewith.
  • the process liquid 24 in the freestanding liquid region 50 i.e., referred to herein as the freestanding liquid 83
  • the freestanding liquid 83 is extracted via fluid flow outlet arrangement 70. This extraction occurs at or below the freestanding liquid surface 89 by means of a fluid flow outlet port 72 and a fluid flow outlet conduit 74.
  • the rate of removal of the process liquid is controlled by a fluid flow outlet control valve 76 and pump 52'.
  • the freestanding liquid 83 generally drains more easily than liquid does from conventional reactors because the downwardly moving bed of carbonaceous solids 22 is not in direct solids flow communication with the fluid flow outlet port 72.
  • freestanding liquid 83 is less turbulent, as discussed above, suspended solids therein are allowed to settle to a greater extent.
  • fluid flow outlet arrangements 70 may be used to advantage.
  • fluid flow outlet ports such as port 72, for example, could be distributed approximately equidistant from each other, around the internal side wall 25 of the reactor vessel 20.
  • a plurality of fluid flow outlet arrangements 70 is advantageous because it allows for a distribution of the fluid flow within the freestanding liquid region 50, which results in a further reduction in the liquid flow velocity and resultant turbulence in the freestanding liquid region 50. Similar advantages result from use of a plurality of overflow drains 78.
  • the retaining structure 40 preferably possesses dimensions that produce efficient and economical extraction of process liquid. As shown in the preferred embodiment in Figure 4, the retaining structure 40 extends downward below the freestanding liquid surface 89 to a sufficient extent such that adequate capacitance is provided to satisfactorily meet fluctuations in the level of the freestanding liquid surface 89 relative to the fluid flow outlet port 72. That is, the height of the retaining structure wall 42 is preferably sufficient -36- to allow for fluctuations in the rate of extracted fluid flow due to the demand for the process liquid 24 at the highest expected extraction rate without the level of the freestanding liquid surface 89 generally falling below the level of the fluid flow outlet port 72.
  • the retaining structure 40 preferably extends downward below the freestanding liquid surface 89 to a sufficient extent such that the turbulence induced upon fluid flow extraction at the highest expected extraction rate is below that which would entrain solid particles of a size that would result in uneconomical filtration after extraction of the process liquid 24. It is to be understood, however, that filtering systems, such as screens, filters, etc., may be useable with outlet flow from the reactor arrangement of the present invention, in order to entrap very slow settling fines. Also, the retaining structure 40 preferably does not extend downward below approximately the minimum depth necessary to meet the above objectives.
  • the retaining structure 40 is preferably at least about 6 feet high (2.0 meters) , with at least approximately 3 eet (1.0 meter) submerged below the level of the freestanding liquid surface 89.
  • ring portion 43' of the retaining structure 40 is sufficiently small, e.g., has a sufficiently small diameter if in the form of an annular structure, to permit a sufficiently large freestanding liquid region 50 such that the influx fluid flow velocity of the process liquid 24 into the region 50 is below that which would fluidize particles of a size that would prohibit economically feasible extraction.
  • the freestanding liquid region 50 should be large enough to allow for a major portion of fluidized solid particles (except, for example, fines) to settle.
  • the size of the retaining structure 40, and hence the size of the freestanding liquid region 50 should be optimized in view of the possible need to filter extracted liquid to remove entrained particles. It may be economically feasible to remove certain sized particles (fines) along with the process liquid 24, but there is a point approached at which the entrained particles are too large for economical extraction, i.e., extraction without relatively extensive filtration.
  • the diameter of the ring 43' is about 70% to 80% of the diameter of the reactor vessel 20.
  • a typical reactor vessel is about 9 feet (2.7 meters) in diameter (internal) , with a volume sufficient to treat about 100 tons (9.1 x 10* kg) of solid material per hour.
  • the cross-sectional area of the ring 43' is about 45 to 51 ft 2 .
  • retaining structure 40 be impervious to fluid flow through the outer wall 42. However, it will be desirable that it be such as to inhibit substantial solids flow therethrough, so as to inhibit solids flow directly to the freestanding liquid region 50, from the retained solids 85.
  • the system and method of hydrothermal reforming of a preferred embodiment of the present invention provides improvements in the reduction in the amount of the entrained solids, also a reduction in the size of the particles entrained, particularly if processing parameters, such as fluid flow rate, are optimized.
  • One of the advantageous aspects of this invention is to allow for treatment of materials with fractions containing a relatively small particle size, without a resulting problem of solids entrainment in liquids drawn off. That is, even materials with a significant portion of solid particles less than about 1/4 inch (6 mm) may be advantageously beneficiated with the systems and methods of the present invention.
  • the retaining structure 40 shown in the preferred embodiment of Figure 4 extends upward above the freestanding liquid surface 89 to a height sufficiently high such that solids being fed into the reactor vessel 20 are generally inhibited from spilling into the freestanding liquid region 50.
  • process gases such as C0 2
  • a process gas receiving region 96 should be able to enter the retaining structure internal volume 41. This should be done, however, only to the extent that influx gas flow velocities do not cause extensive turbulence in the retained solids region 46.
  • gas flow tube 98 extending upward from an upper portion of the lower countercurrent reactor region 26 through the freestanding liquid region 50, should be arranged such that ejected gases, liquids, and solids are transported essentially completely into the retaining structure internal volume 41, and above the retained solids 85.
  • the retaining structure 40 may be constructed of any material suited to economical survival within the environment of the reactor vessel. This may include, but is not limited to, steel of approximately 1/8 inch (3 mm) thickness of a suitable composition that withstands abrasion and corrosion, such as mild steel.
  • the retaining ring portion 43' of structure 40 may have a wall 42 that is perforated.
  • the size of the perforations should allow process liquid 24 and gases to pass through the perforations, but generally not allow solid material in the retained solids region 46 to pass through into the freestanding liquid region 50.
  • the carbon dioxide and other gases produced by the hydrothermal reforming process such as water vapor, carbon monoxide, methane, and sulfur -40- dioxide, are herein referred to as the process gases.
  • These process gases migrate upward in the reactor vessel 20 because of the lower density of each of the gases relative to the liquids and solids. Generally, it is observed that the process gases are generated in an amount sufficient to obstruct or disturb the downward flow of the bed of carbonaceous solids 22 countercurrent to the upward flow of the process liquid 24.
  • a gas flow tube 98 (as seen in Figure 4), i.e., a "bubble breaker,” provides for a means to divert or shunt at least a portion of the carbon dioxide and other gases (along the direction of arrow 111) produced around a portion of the pile of submerged solids 84. Additional advantage is observed if a plurality of the gas flow tubes 98 are used. This added means will greatly obviate the problem of the disturbed countercurrent flow.
  • a gas flow tube 98 as shown in Figure 4 comprises a conduit 112 having a first end 113 and a second end 114.
  • the second end 114 projects into the lower countercurrent reactor region 26, preferably terminating in the lower part of the coal preheat zone 29. It is desirable to have the second end 114 high enough up in the coal preheat region 29 so that generally most of the steam associated with the gas can condense, but low enough in the coal preheat zone so that heterogeneous mixing due to the turbulence caused by ascending bubbles is somewhat minimized.
  • the gas flow tube second end 114 is preferably covered with a protective arrangement (not shown) with small enough openings to prevent large particles from being transferred into the conduit 112.
  • the second end 114 of the gas flow tube 98 is also preferably placed low enough in the lower countercurrent reactor region 26 such that a static pressure differential maintained between the upper and lower countercurrent reactor regions 26 and 48, respectively, provides for efficient and rapid transfer of the process gases from the point of formation, i.e., in the reaction zone 28, to the process gas receiving region 96, along the direction of arrow 111.
  • the first end 113 of the gas flow tube 98 is located within the process gas receiving region 96 of the reactor vessel 20, and is preferably directed in such a way that liquid entrained by the rapid transport of the process gases along the direction of arrow 111 throu.jh the gas flow tube 98 will impinge upon the retained solids 85, so as not to cause undesired turbulence in the freestanding liquid 83. In Figure 4, this is provided by a bend 118 in the gas flow tube 98 near the first end 113.
  • the gas flow tube 98 may occasionally have the appearance of a percolator with streams of hot water being ejected by bursts of low pressure gas.
  • a typical gas flow tube 98 has a diameter in the range of about 3 inches to 6 inches. Referring to Figure 4, the tube 98 shown extends through upper portion 43 of retaining structure 40. While advantage is derived from such placement, and from a plurality of tubes 98 so placed, in some applications it may be desirable to position a similar tube or tubes centrally, i.e., to project through a central portion of ring portion 43'. It may be desirable, for tubes so placed, to provide an inverted U-bend in an upper end, to inhibit plugging from the solids feed.
  • Reactor arrangements of the present invention require carbonaceous solids to be delivered from ambient pressure, or near ambient pressure, to the operating pressure of the reactor vessel.
  • Hydraulic lockhoppers are typically used to transfer materials between regions at substantially different pressures. For example, a solid substance is added to a lockhopper at ambient pressure, while the lockhopper is sealed off from the region of higher pressure. Water is then typically added to the lockhopper (hence, hydraulic lockhopper), and the combination is pressurized to that of the region of higher pressure. The lockhopper is then opened to the region of higher pressure and the solid material is charged into the receiving region, along with the liquid that is used to pressurize the lockhopper.
  • a preferred embodiment of the present invention uses a solids feed system 120 that accomplishes the goals of charging the reactor with the feed solids while reducing the volume of superfluous liquid added to the reactor vessel.
  • the reactor vessel depiction in Figure 5 is a vessel 20 as described above, and shown in Figure 4.
  • the solids are fed to the vessel 20, without the need of a dewatering means, such as a high pressure screw conveyor.
  • a dewatering means such as a high pressure screw conveyor.
  • the solids feed system 120 includes use of a feed hydraulic lockhopper 122, e.g., a feed hydraulic lockhopper, for feeding the solids directly into the reactor vessel 20, i.e., without utilizing a system to dewater the solids.
  • the solids feed system 120 includes a solids feed lockhopper inlet valve arrangement 124, a feed lockhoppe - liquid filling valve arrangement 127, a feed lockhopper liquid conduit arrangement 128, and a feed lockhopper outlet valve arrangement 129.
  • the feed hydraulic lockhopper 122 is preferably pressurized by process liquid 24 extracted from the reactor vessel 20.
  • Figure 5 does not indicate that every lockhopper has a liquid conduit for directing process liquid thereto, it is understood that this is the case.
  • this description is presented in terms of a conventional hydraulic lockhopper, a more detailed description of a solids feed system and a feed lockhopper specifically designed for advantageous use with the reactor vessel of the present invention appears below.
  • carbonaceous solids are transferred from ambient pressure to the operating pressure of a hydrothermal reforming reactor vessel 20 by use of a feed hydraulic lockhopper 122.
  • the feed hydraulic lockhopper 122 is charged and pressurized up to or near the pressure of the reactor vessel 20 using a liquid such as water.
  • a dewatering means is used to reduce the amount of liquid introduced into a conventional reactor. Because, however, at least a portion of the process liquid 24 is used to charge the solids feed system 120 in a preferred embodiment, the amount of superfluous and extraneous liquid introduced into the reactor 20 is reduced. That is, at least a major portion of the liquid that enters the reactor vessel 20 along with the feed solids 51 has been previously extracted from the reactor vessel 20. Thus, it is not critical to remove surface liquid from the carbonaceous solids before charging the reactor vessel 20 for efficient operation.
  • the solid material is charged into the feed hydraulic lockhopper 122 through the solids feed lockhopper inlet valve arrangement 124.
  • the feed hydraulic lockhopper 122 may be charged with solid materials by any of a variety of means known in the coal processing industry for loading. Although each lockhopper intermittently charges the reactor with solids, it is understood that solid material, such as coal, can be charged continuously to the reactor vessel 20 by the use of a plurality of the lockhoppers 122, which can be sequentially fed by a bunker arrangement (not shown) .
  • the rate of the solids feed into the lockhopper 122 may be synchronized with the rate of the lockhopper operation of loading the solid material into the reactor vessel 20 to reduce lockhopper cycle repetition, if so desired.
  • Process liquid 24 is added to the feed hydraulic lockhopper 122 to charge and pressurize it. This is done by means of the feed lockhopper liquid conduit arrangement 128 along the direction of arrow 133.
  • the process liquid 24 typically contains dissolved and entrained solids and gases that have been released from the carbonaceous solids. Should the lockhopper system require a minimum-size entrained particle for normal operation of the lockhopper liquid filling valve arrangement 127, the process liquid delivered to the feed hydraulic lockhopper 122 can be filtered by any of a variety of means known in the art, such as a filter 140, to such an extent as to meet the necessary standards for efficient operation of the solids feed system 120. Fluid flow may be controlled by a variety of pump means, symbolized at 52'. Feed hydraulic lockhoppers are described in the literature; see, for example, U.S. Patent No. 3,729,105.
  • the solid material is discharged from the solids feed hydraulic lockhopper 122 into the reactor vessel 20 through feed lockhopper outlet valve arrangement 129.
  • Both the inlet valve arrangement 124 and the outlet valve arrangement 129 may be simple open/shut valves of existing art, as for example, a high pressure ball valve.
  • the inlet and outlet valve arrangements 124 and 129 are preferably double valved. That is, there are actually two valves for each of the lockhopper inlet and outlet, one of which can be disabled for repair without interrupting the operation of the process.
  • a more detailed discussion of a solids feed system is discussed in further detail below (see Figures 10-12).
  • a lockhopper arrangement including means for reducing gas pressure from the lockhopper and means for charging and pressurizing the lockhopper with liquid is discussed in greater detail.
  • This arrangement includes a unique and preferred valve arrangement for delivering solids to the reactor vessel while under a first pressure and receiving solids while under a second, lower, pressure.
  • a portion of the process gases from the process gas receiving region 96 in the upper countercurrent reactor region 48 may be charged into the feed hydraulic lockhopper 122 (along the direction of arrow 141) to force the material downward by pressure.
  • the process gases are removed from the process gas receiving region 96 through a vent arrangement 142 (along the direction of arrow 143) and transported to the feed hydraulic lockhopper 122 through the gas flow outlet conduit 144 and the feed lockhopper gas conduit 146.
  • Process gas is directed to only one lockhopper in order to simplify the diagram.
  • the process gases are preferably pressurized to a pressure slightly greater, i.e., about 50-70 psi, than that in the upper countercurrent reactor region 48, by the gas compressor arrangement 148.
  • a spray of liquid may be provided by a feed lockhopper liquid spray system (not shown in Figure 5) .
  • the source of liquid for this washing/spraying process is preferably the same as used in pressurizing the feed hydraulic lockhopper 122, i.e., the slightly pressurized extracted process liquid 24. It is noted that the process liquid 24 used for the spray as well as that used to pressurize the feed hydraulic lockhopper 122 is recycled back into the reactor vessel 20.
  • the use of a high pressure screw conveyor to dewater solids from a hydraulic lockhopper before charging the reactor has been preferably eliminated.
  • the feed solids 51 can be advantageously charged directly into the reactor vessel 20 from the feed hydraulic lockhopper 122.
  • the preferred embodiment of the present invention generally: avoids need for the high pressure screw dewatering conveyor; eliminates need for a control valve that varies the solids flow from the lockhoppers, which may become easily plugged; and, reduces the amount of superfluous liquid entering into the reactor vessel.
  • At least a portion of the process liquid 24 extracted from the freestanding liquid region 50 is directed through the fluid flow outlet arrangement 70 to the fluid flow inlet arrangement 60 (along the direction of arrow 151) and recycled into the reactor vessel 20.
  • This liquid may be pressurized by a pump 52 and/or 52' , as shown in Figure 5, which may be of a variety of types, with encapsulated motors.
  • valve arrangement 53 may be used to direct fluid flow to a solids discharging system, which operates out of opening 54 and is discussed below.
  • at least a portion of the process liquid 24 may be directed to a water treatment system 158 along the direction of arrow 159. Again, it may also be directed to system 158 via overflow orifice 78 along the direction of arrow 160.
  • preferred applications and arrangements of the present invention do not include extractions of any fluid from below the area in the lower countercurrent reactor region 26 in which the hydrothermal reforming reaction occurs, i.e., the reaction zone 28.
  • the extraction occurs essentially in or near the lower portion of the lower countercurrent reactor region.
  • the liquid extracted from this region has often been used to preheat the carbonaceous solids before they are charged into the reactor.
  • this is not necessarily a very efficient use of energy resources.
  • the process liquid extracted from the lower portion of the lower countercurrent reactor region generally has a relatively high thermal energy content. This is then applied to a solids material with a relatively low thermal energy content. It will become apparent through the discussion below that it is more efficient to utilize the system and method defined in a preferred embodiment of the present invention for applying heat recovery to the process.
  • the process liquid 24 (moving along the direction of arrow 23) that has gone through the reaction zone 28 is used to preheat the downwardly moving solids 22 (moving along the direction of arrow 21) as they enter the reaction zone 28.
  • the heat transfer occurs by means of this countercurrent flow.
  • the process liquid 24 is removed from the upper countercurrent reactor region 48 and is preferably pressurized by the extraction pump 52'.
  • the process liquid 24 is then directed to the solids feed system 120 (along the direction of arrow 133) where it pressurizes the feed hydraulic lockhopper 122 and heats the solids somewhat before they are charged into the reactor 20.
  • steam is used as a source of heat for proper operation of reactor vessels for such operations.
  • Steam is generally and preferably introduced into the lower portion 33 of the lower countercurrent reactor region.
  • Steam may be used in some systems and processes according to the present invention and introduced at steam input arrangement 161 ( Figure 5); however, it would be advantageous to use alternate sources of thermal energy for a number of reasons which will become apparent from the following discussion. For example, steam adds extraneous water into the system, which as discussed above can be detrimental. Therefore, it is advantageous to reduce the amount of steam put into the hydrothermal reforming system, by either heat recovery methods or by secondary sources of energy.
  • a preferred embodiment of the present invention utilizes a relatively efficient method of applying heat recovery to the process of hydrothermal reforming of low rank coals.
  • this method reduces the introduction of extraneous liquid into the process, and involves removal of the process liquid 24 from the reactor vessel 20 at a location above the hydrothermal reforming reaction zone 28.
  • This method of heat recovery results from preferably allowing for the removal of the process liquid 24 from the reactor vessel 20 and through the fluid flow outlet arrangement 70, and recirculation of this liquid (along the direction of arrow 151) back into the reactor vessel 20 for utilization of the thermal energy contained therein.
  • process liquid is extracted from the upper countercurrent reactor region 48.
  • the amount that is extracted preferably provides or results in a sufficient flow of the upwardly moving liquid to effectively beneficiate the solids. That is, the amount of liquid extracted will affect the fluid flow.
  • This fluid flow should be sufficient to flush the water associated with the descending solids 22, e.g., inherent water, out of the solids 22 and into the liquid 24 in the hydrothermal reforming reaction zone 28 where it proceeds upward.
  • the location in the reactor vessel 20 at which the process liquid 24 is preferably removed is that level or region in the reactor at which the process liquid 24 is generally the coolest.
  • the process liquid is removed from the upper countercurrent reactor region 48. Once the upwardly moving process liquid 24 reaches region 48 a large portion of thermal energy contained within the process liquid 24 has been removed and transferred to the descending submerged solids 84 in the hydrothermal reforming reaction zone 28.
  • the process liquid 24 that is recycled back into the reactor vessel 20 through the fluid flow inlet arrangement 60 is preferably in an amount and rate that is just sufficient to provide the desired temperature of the wet processed solids before they are discharged from the reactor vessel 20. That is, a sufficient amount of the recirculated process liquid 24 is introduced into the reactor vessel 20 such that the process liquid 24 cools the beneficiated solids to a desired temperature level before removal. In certain circumstances, such as operation under nonequilibrium conditions, it may be advantageous to provide a means for further cooling the recirculated water, such as by a heat exchanger 170.
  • the temperature of the process liquid 24 in the upper countercurrent reactor region 48 is sufficiently cool for recirculation directly back into the reactor vessel 20 through the fluid flow inlet arrangement 60.
  • the solids have been retained in the reactor for a sufficient length of time for the heat exchange process to cool the solids to the desired exit temperature.
  • This secondary source may result from the use of electrical energy.
  • the use of electrical energy to provide thermal energy to the operation of the process has certain advantages. For example, the dilution of effluents in the waste extraction water stream caused by using steam as the sole process heat source can be reduced. The waste stream may, therefore, be highly concentrated, and thus more efficiently treated, by partially replacing steam heat with electrical energy. Also, the use of electrical energy as a supplemental means for providing thermal energy removes the limitations resulting from total dependence on a steam supply and its limited capacity. Thus, the combined use of steam and electrical energy as a means for providing thermal energy to the system of the present invention makes possible the use of steam from an existing steam supplier.
  • electrical energy may be introduced into the reactor vessel 20 in a variety of ways, it is preferably introduced at a position relative to the height of the column of the bed of submerged solids 84 such that an optimum amount of thermal energy is input.
  • the resistive element 182 may be the process liquid 24 itself, since it will include salts derived from the bed of solids.
  • a three phase alternating current power using the electrodes 184, 185, and 186 which are distributed approximately equidistant from each other near the reactor vessel's internal side wall 25, as shown in Figure 5, will provide a good distribution of thermal energy.
  • the rate of heating can be controlled by existing power control means and techniques. Examples of a power control system 188 are transforming voltage control, or solid-state rectifier control.
  • the internal side wall in this application, should, of course, be electrically insulated, for example, by existing methods such as ceramic, plastic, or organic linings or coatings.
  • What will be preferred in systems according to the present invention is an arrangement that does not typically and readily become plugged and that does not require vigorous agitation of the packed bed, but which provides a controlled positive removal of the solids. It will also be desired that the removal arrangement also not result in a significant draw of process fluid, which would interfere with the hydrothermal reforming process.
  • Preferred applications of the present invention include an improved method for the removal of carbonaceous solids, the majority of which has been processed, i.e., beneficiated, from the reactor vessel 20. This improvement simplifies construction of the lower portion 33 of the lower countercurrent reactor region 26, and in some ways reduces the chance of process failure by plugging.
  • Screw conveyor 210 comprises an auger 212 located within an enclosure 214, and inserted through a solids discharge opening 216 in the reactor internal side wall 25 within the lower portion 33 of the lower countercurrent reactor region 26.
  • the screw conveyor 210 is angled upward with sufficient elevation to maintain the liquidus level 218 below an exit opening 220 of the auger enclosure 214.
  • this positioning advantageously allows for a controlled, positive removal of the beneficiated carbonaceous solids 22 from the reactor vessel 20 while inhibiting extraneous flow of the process liquid 24 with the solids 22. That is, the beneficiated solids are positively removed and not just allowed to pass out of the reactor under the influence of gravity alone.
  • the screw conveyor 210 simultaneously acts as a solids extractor and dewatering screw. It will be understood that in some applications of the present invention, a plurality of screw conveyors 210 may be used to advantage.
  • a first end 222 of the auger 212 to the internal side wall 25 of the reactor vessel 20 at a position that is opposite the opening 216. This can be done, for example, by using a pad 224 with a bearing 225 attached thereto. Such an arrangement can be produced without penetration of the reactor side wall 25 opposite the opening 216.
  • a grease fitting opening 227 in the internal side wall 25 near the pad 224 and the bearing 225 arrangement is preferably fitted with a grease fitting 228 and a line 229 for transfer of the grease to the bearing 225.
  • a drive motor 234 is affixed to a second end 236 of the auger 212 to control the rate of withdrawal of the beneficiated carbonaceous solids 22 from the reactor vessel 20. Any of a variety of drive motors may be used, as for example, a reversing variable speed encapsulated motor.
  • the wet beneficiated carbonaceous solids 22, generally free of the extraneous process liquid 24, are preferably transferred, as for example by dropping, from the screw conveyor 210 through the exit opening 220 in the enclosure 214 into a product lockhopper 240.
  • the process gases are directed to the screw conveyor 210 (along the direction of arrow 243) from the process gas receiving region 96 through the vent arrangement 142.
  • the process gases are preferably pressurized by the gas compressor 148 to a sufficient pressure such that the liquidus level 218 within the screw conveyor 210 is maintained below the auger second end 236 to prevent discharge of the process liquid 24 along with the beneficiated carbonaceous solids 22.
  • pressure about 50 to 70 psi in excess of the pressure of the gases in the process gas receiving region 96 is sufficient.
  • Hydraulic lockhoppers are preferably used as the product lockhopper 240 for discharging the beneficiated carbonaceous solids 22 to ambient pressure, from the reactor vessel 20, which is at an elevated pressure.
  • the fluid used to fill the lockhopper is preferably the process liquid 24, which has been removed from the upper countercurrent reactor region 48 via the fluid flow outlet arrangement 70, directed to and through the product lockhopper liquid conduit 245 (although direct connection between 70 and 245 is not shown in Figure 6), and used as a spray to flush the product into the product lockhopper 240.
  • the solids discharge system 200 provides a means for transferring the beneficiated carbonaceous solids 22 from the reactor vessel 20 into the lockhopper 240 in a controlled and generally nonplugging manner.
  • the process liquid 24 is generally separated from the beneficiated solids 22 being extracted from the reactor vessel 20. That is, generally only processed, i.e., beneficiated, solids are discharged from the reactor. This is not intended to mean, however, that there is no surface and/or residual process liquids associated with the removed solids, nor does it mean that the solids are thoroughly beneficiated.
  • the product lockhopper 240 may either operate with the wet beneficiated solids product alone, or it may operate as a hydraulic lockhopper filled with the process liquid 24, a portion of which is extracted from the upper countercurrent reactor region 46 and directed to the . lockhopper 240.
  • the use of extracted upper reactor process liquid to fill the product lockhoppers provides a thermodynamic advantage because use of extraction liquid in lieu of reactor bottom process liquid keeps the process liquid flowing in the right direction, i.e., upwardly in the reactor.
  • the solids discharge system 200 allows for positive extraction of the beneficiated solids with reduced likelihood of plugging, generally without removal of relatively large amounts of processing liquids, and generally without vigorously stirring the packed bed of solids.
  • a screw conveyor or plurality of screw conveyors may be positioned such that the exit opening is located generally below the liquidus level.
  • no gas blanket is used, i.e., no process gases are directed to the screw conveyor, and the beneficiated carbonaceous solids dropped into the product lockhopper are immersed in the process liquid.
  • Either the process liquid from the lower countercurrent reactor region may be used to fill the product lockhopper, the liquid separated from the solids upon release from the lockhoppers, pressurized and reinjected at the screw conveyor entrance, i.e., creating a circulating loop of process liquid, or the process liquid that has been slightly pressurized by the extraction pump (shown in Figure 5) may be injected into the solids stream exiting the reactor vessel at the juncture of the screw conveyor at the reactor vessel, as in the solids discharge system 200 discussed above.
  • An alternate embodiment for discharging beneficiated carbonaceous solids is particularly well adapted for use when the beneficiated solid material consists of a relatively large proportion of fine particles, i.e., contains at least 40% by weight of particles having a size less than about 0.1 inch (2.5 mm) .
  • This embodiment allows for direct extraction, i.e., without going through a system such as a lockhopper, of the solid particles to ambient pressure.
  • the reactor 20 may be as described above for Figure 4, although there is no requirement that it be so.
  • the solids discharge system 300 comprises a long and the narrow screw conveyor 310 with a long auger 312 within the enclosure 314. It will be understood that in some applications a plurality of screw conveyors 310 may be used, to advantage.
  • the auger 312 is attached to a drive motor 334 and to the reactor 20 in a manner similar to that of the screw conveyor 210 discussed above.
  • the screw conveyor 310 and the auger 312 are typically narrower in cross section than the screw conveyor 210 and the auger 212 discussed above. This longer and narrower arrangement allows for direct discharge of the beneficiated carbonaceous solids 22 to ambient pressure from the pressurized reactor vessel 20. The pressure drop is generally distributed over the length of the screw conveyor 310. At least a portion of the process liquid 24 is withdrawn from the lower portion 33 of the lower countercurrent reactor region 26 while this solids discharge system 300 is in use.
  • FIG. 8 Another embodiment of means for discharging solids is the solids discharge system 400, is shown in Figure 8.
  • the reactor 20 may be as described above for Figure 4, although there is no requirement that it be so.
  • beneficiated solids from the densely packed submerged solids 84 can be continuously extracted from the lower portion 33 of the lower countercurrent reactor region 26 with the use of a hollow core screw conveyor arrangement 410.
  • a plurality of screw conveyor arrangements 410 may be used.
  • This embodiment generally eliminates the flow of the process liquid 24 from the reactor vessel 20. This is particularly advantageous to the overall thermodynamics of the thermochemical beneficiation process for reasons we have discussed above.
  • process liquid that has been extracted from the upper countercurrent reactor region is recirculated in a novel and efficient way from the fill liquid used to charge product lockhopper. This practice is also advantageous to the overall thermodynamics of the process.
  • the screw conveyor arrangement 410 with an auger 412 enclosed by an enclosure 414, is installed so as to penetrate the reactor internal side wall 25 in the lower portion 33 of the lower countercurrent reactor region 26.
  • the shaft 415 of the auger 412 is hollow, with a relatively large diameter. This relatively large diameter enhances the beam stiffness of the auger 412. That is, generally the larger the diameter, the stronger or stiffer is the auger shaft 415.
  • the auger 412 located within the enclosure 414, is inserted through a solids discharge opening 416 in the reactor internal side wall 25 and is positioned such that the exit opening 420 allows for the expulsion of both solids and liquid during operation.
  • a first end 422 of the auger 412 is supported by a bearing 425 at the reactor vessel internal side wall 25 at a location opposite the point of entrance of the screw conveyor 410. Solids and process liquid are transferred by rotational motion of the auger 412, out of the densely packed bed of carbonaceous solids 22, i.e., the submerged solids 84, within the reactor vessel 20. For solids with portions of relatively large particle sizes, it is preferable to have a serrated edge 432 at or near a point at which the extraction auger 415 exits the reactor vessel 20 and enters the solids discharge opening 416.
  • This edge 432 (similarly to analogous edges in the embodiments of Figures 6 and 7) advantageously shears some of the larger solid particles and inhibits jamming of the auger 412. It may also be advantageous to provide a drive motor 434, which is attached to the auger second end 436 and which has a reversing feature, in case some of the larger solid particles are relatively hard, as would be the case when stones are present along with the coal.
  • the auger 412 needs to be of a length that is sufficient to extract the beneficiated solids from the reactor vessel 20 and convey the mixture of solids and liquids to a convenient location for the product lockhopper 440.
  • the solids/liquids are discharged into the product lockhopper 440, preferably into an arrangement of a plurality of the product lockhoppers 440 with a toggling tripper 442 to direct the flow of the material.
  • This method is superior to simple gravity settling, in that it provides a convective conveyance of the solid particles downward towards the product lockhopper 440, which greatly accelerates the throughput.
  • the flush liquid directed through the line 441 is obtained from the lockhopper 440, which was charged with liquid before initiation of the process.
  • the flush liquid in line 441 is forced from the product lockhopper 440 by a relatively low total developed head pressure, high volume pump 443.
  • the pump 443 may be an encapsulated pump, or any other suitable pump.
  • the rate of removal of nonsolids bearing the flush liquid directed through line 441 is preferably commensurate with the rate of arrival of solids from the screw conveyor 410, and establishes a convective circulation where the solids 22 are more rapidly conveyed downward into the product lockhopper 440 than by gravity settling alone.
  • the pump 443 used to extract flush liquid from the product lockhopper 440 is protected by a screen 446 of sufficient size and fineness to operate for at least one cycle.
  • the screen 446 is cleared of solid contaminating material each cycle by a backflushing action caused by the discharge upon depressurization of a small accumulator 450.
  • the small accumulator 450 a device which stores energy, usually through the compression of a suitable gas, often air, contained in a suitable container, often, though not necessarily, includes an orifice in communication with line 441.
  • the accumulator 450 normally exists at the relatively high pressure of the screw conveyor 410 and lockhoppers 440. When the lockhopper is depressurized to release material to the ambient pressure conditions outside, the accumulator depressurizes as well, forcing a small amount of process liquid back along line 441 (which forces back flushing action of screen 446).
  • Flow along the rest of line 441 is made not possible during this operation by either a single direction valve (a check valve 451) or other suitable means of positive flow control as currently exists.
  • the check valve is placed between the juncture of the accumulator with line 441, and the suction of the pump 443.
  • the flush liquid which is directed through line 441, is preferably removed from the product lockhopper 440 at a rate commensurate with the rate of arrival of the solids. Furthermore, a portion of the flush liquid, upon combining with the solids/liquids in the screw conveyor arrangement and passing through exit opening 420, is partitioned into a return liquid chamber 452 defined by a baffle 453. The rotational motion of the auger 412 displaces a relatively incompressible volume of the solids/liquids towards the exit opening 420. This action is met either by an increase in pressure at the exit opening 420 relative to the pressure at the solids discharge opening 416, or by a displacement of an equal volume liquid elsewhere, or a combination of both.
  • the arrival of the relatively incompressible volume of the solids/liquids is generally offset by a volume of liquid, e.g., water, displaced first from the product lockhopper 440, then into the return liquid chamber 452, then through the ports 455 in the second end 436 of the hollow auger shaft 415, through the egress ports 457 at the first end 422 of the auger shaft 415, and into the reactor vessel 20, where, as will be shown elsewhere in this description, the lockhopper flush liquid of the line 441 originated.
  • a volume of liquid e.g., water
  • a loose collar 460 around the egress ports 457 and, furthermore, to provide a return liquid pipe 462.
  • the return liquid pipe 462 shunts the liquid that has been transported through the auger shaft 415 away from the vicinity of the extraction auger 412.
  • This arrangement has at least two desirable features.
  • the liquid shunted through the pipe 462 may be directed away from the extraction auger 412, which allows the solids to attain the greatest settling density for efficient extraction.
  • the displacement of the liquid in the lockhopper 440 is met by a nearly equal displacement of the discharged volume of the solids/liquids. This latter volume, however, is discharged at a rate that is slightly higher due to the presence of the additional force provided by the flush liquid of the line 441.
  • the differential is accommodated by the flow of the process liquid and the solids, along with flush liquid, into the return liquid chamber 452, as stated above.
  • the flow velocity of the liquids/solids therein is low enough to permit a settling of all but very small solid particles.
  • generally particulate free liquid will enter the hollow auger shaft 415 and return to the reactor vessel 20 under pressure developed by the delivery of the solids and the process liquid by the screw conveyor arrangement 410.
  • the continuous flow nature of the screw conveyor 410 is augmented by providing more than one product lockhopper 440 per screw conveyor. Although this is not necessary to the performance of the apparatus as described, adding more than one lockhopper improves process throughput and avoids the tendency of the solids flow to begin encroaching into the return liquid chamber 452. By synchronizing the operation of the lockhoppers so that one is always prepared to accept a charge of solids by the end of the fill cycle of another lockhopper, continuous extraction of solids can be achieved, and the rotational speed of the screw conveyor can be operated at a steady state, dependent upon the desired rate of extraction.
  • the filling cycle of the lockhoppers can be interrupted by appropriate control logic, and reverse flow into the hollow auger 412 will occur to balance the pressure differential developed.
  • a preferred embodiment of the present invention incorporates a combined process of hydrothermal reforming, oil agglomeration, and low temperature drying. The advantages of this combination will become apparent in the following discussion.
  • the segregation of the solid material between large and small particles may occur right after discharge from the product hydraulic lockhoppers used in the hydrothermal reforming process. Furthermore, the product lockhoppers may discharge directly onto a screen conveyor. If the oil agglomeration process is tolerant of process liquid, e.g., water, the fines with a particle size of less than about 1/8 inch (3 mm) could be washed through the screen with process waste liquid and hydraulically conveyed to the oil agglomeration tanks. If the oil agglomeration process is not tolerant of the process liquid, the fines could be separated from the process liquid stream by hydrocyclones and vacuum screen drying, or simply by fine screen filtering, prior to transport to the oil agglomeration process.
  • process liquid e.g., water
  • the fines with a particle size of less than about 1/8 inch (3 mm) could be washed through the screen with process waste liquid and hydraulically conveyed to the oil agglomeration tanks. If the oil agglomeration process is not
  • Oil agglomeration provides, for example, the following value to the end product:
  • hydrothermal reforming produces an advantageously beneficiated product for a variety of carbonaceous materials
  • hydrothermal reforming system is preferably and advantageously combined with the oil agglomeration process.
  • advantage is realized by combining oil agglomeration and hydrothermal reforming.
  • low temperature drying is applied to the coarse hydrothermally reformed product and the oil agglomerates. This can be done either separately, or with the two fractions combined together. Following hydrothermal reforming, the equilibrium moisture content of the carbonaceous solids has been permanently reduced. The beneficiated product, however, has not yet fully reached this lower equilibrium moisture content. Low temperature drying is thus preferably applied to efficiently allow the coal product to fully attain the quality necessary for an export quality product, i.e., the lowest moisture content practical. Low temperature drying may be applied in several ways or combination of ways. For example, centrifuging, thermal drying, and aerated storage are considered potential means.
  • the preferred embodiment comprises: centrifuging the wet coarse product only; storing both the coarse and agglomerates in the same storage vessel; and using forced aeration of the storage vessel with air heated to a nominal value of about 150°F (66°C).
  • This heated air is preferably from the hydrothermal reforming plant or nearby plants.
  • the air exiting the forced aeration process is preferably recirculated and used as combustion air in on-site or nearby furnaces, or in other suitable means of disposition.
  • waste-water-treatment (WWT) processes are useable, advanced membrane separation, powdered activated carbon treatment, and biological treatment technologies are preferable.
  • FIG. 9A and 9B A simplified flow chart of this hypothetical example is shown in Figures 9A and 9B ( Figure 9B following from Figure 9A, e.g., "A" in Figure 9A follows to "A” in Figure 9B) .
  • the mass balance for the major constituents is also described; however, no attempt has been made to quantify the minor process constituents, such as sodium content, sulfur, or the minor losses that occur as a natural result of the operation of most real process elements. In other words, the mass balance closure is on only the gross flow of the major constituents.
  • the process is based on the up-grading of a generic North Dakota lignite, but is not limited to this coal.
  • lignite is represented as a "macro-molecule" in which the ash is represented simply as silica (Si0 2 ) its composition could be written as: [C 5i5 H 47 0 11 »27(H 2 0)+1.7Si0 2 ] . This format will be used throughout the description which follows.
  • raw lignite, at 500 which has been crushed to a nominal 3 x 0 size distribution, is fed into the hydrothermal reforming vessel, at 502, at a rate of 142 tons per hour.
  • the wet reformed lignite is removed from the reforming vessel.
  • the wet reformed lignite, at 504 typically has 25% total moisture, 8.5% inherent moisture, and its oxygen content has been reduced by 30%.
  • the wet reformed lignite is removed from the reforming vessel at a rate of 120 tons per hour.
  • off-gas i.e., process gases, at 506, and process water, at 508, are removed from the reforming vessel.
  • the off-gas is typically primarily carbon dioxide (C0 2 ) , saturated with water vapor, and contains small amounts of light hydrocarbons, carbon monoxide (CO), and sulfur dioxide (S0 2 ).
  • the process gases are removed at a rate of 4 tons per hour.
  • Process water, produced as a by-product of the reforming reaction is removed from the reactor at a rate of 18 tons per hour.
  • the reaction can be expressed as: (1) 194[C 54 H 47 0 11 »27(H 2 0) + 1.7Si0 2 ] ⁇
  • Water is expressed twice in the reaction (1) to describe the water associated with the surface moisture of the wet coal product as separate from the free water produced in the system. Free water is further defined as water which will drain or flow freely from the process and its product. The process gases are vented from the reactor vessel under controlled conditions and the free water is removed by methods described previously.
  • wet Coal Product Screening The wet coal product from the reforming reactor vessel is screened, at 510, into two size distributions: coarse at 512, and fine at 514. Typically, the split point is at a size of approximately 1/8 inch (3 mm). With this "split point" approximately one fourth of the total processed wet coal product flows to the fine coal stream.
  • the method used to screen the coal is existing commercially available technology. Wet traveling screens with sprays are an example.
  • the coarse stream typically flows at a rate of about 86 tons per hour, the rate of the fine stream is about 34 tons per hour.
  • the coarse stream has a slightly lower total moisture content than the fine stream due to its lower average surface area to volume ratio.
  • the fine coal stream has a somewhat increased average ash content due to a concentration of mineral matter (ash) .
  • the increased ash content is not due to an actual increase in the inherent mineral content of the coal, but to the inclusion within the aggregate fine coal stream of small mineral grains liberated in the fracturing of larger coal particles.
  • This process element may be represented by the following reaction: ( 2 ) 194 [C 53 Hdon0 9 «4 . 5 (H 2 0 ) + 1 . 7Si0 2 ] ⁇
  • the fine wet coal product enters into the oil agglomeration process element, at 516 (in Figure 9B along arrow "B"), at a rate of about 34 tons per hour.
  • Oil in this case represented as C 12 H 12
  • the wash slurry stream created by the oil agglomeration process leaves the process at a rate of 10 tons per hour (8.5 tph water, 1.5 tph ash), at 520, and is directed to the waste water treatment facility.
  • the coal/oil agglomerates at 522, having been stripped of most of thei-r surface moisture by the physical replacement of oil-for-water, have 8% total moisture and 6% ash. Since part of the ash is sulfur-containing pyrites, the sulfur content of the agglomerates is typically less than the average sulfur content of the feed coal.
  • the reaction of the oil agglomeration process element can be represented as follows:
  • coal/oil agglomerates are directed to the combined low-temperature drying/storage area, at 524, where they are blended with the coarse coal for eventual product out for sale. Centrifugal Drying
  • centrifugal dryers 526 (in Figure 9B) , are used to "spin dry" the coarse coal fraction (shown in Figure 9A) .
  • This process element simply removes surface moisture from the coarse coal particles, from a total moisture content of 22% down to 15%.
  • the wet coal stream enters the centrifugal dryers at a rate of 86 tons per hour, leaves at a rate of 80 tons per hour, with a process water stream of 6 tons per hour, at 527, reporting to the waste water treatment facility.
  • This process element can be represented by the following reaction:
  • a separate drying process element prior to storage may also be possible, however, this example assumes that the low- temperature drying occurs in the storage silo. It is anticipated that a relatively low-temperature drying gas ( ⁇ 150°F, i.e., 60°C), likely waste heat from a nearby combustion process, will be forced into the top of the specially constructed storage silo. This low level temperature gas will be forced through the coal bed in a downward direction at a relatively slow rate. Moist process gas and water are collected at the bottom and are removed.
  • This silo will maintain the product at a sufficiently elevated temperature for the product to essentially approach its equilibrium moi ⁇ re content, or below it.
  • the final moisture removed i vie the product will be partly evaporated and partly drained off the bottom of the storage silo. After completing this incubation period, the final product is achieved .
  • the reaction can be expressed as :
  • the three tons per hour of liquid water, at 529, produced reports to the waste water treatment plant and, the 3 tons per hour of vapor, at 530, produced escapes with the drying gas.
  • the rate of drying produced by this process element is expected to be nonlinear, thus the production rates of vapor and liquid are represented as average over the operation of the facility.
  • the final product, at 532, has an aggregate typical composition of (quantities in percent) :
  • the product will be produced at a rate of 100 tons per hour. This represents a significant improvement over the raw lignite feedstock.
  • the process elements are inherently efficient, making the overall process very energy efficient.
  • the cumulative quantity of the separate feedstocks reporting to the commercially available waste water treatment facility is 35.5 tons per hour. After treatment, this water can be sold as a by-product.
  • Solids Feed System Feed Lockhopper
  • Conventional hydraulic lockhoppers i.e., liquid- filled lockhoppers
  • conventional hydraulic lockhoppers are safer to use.
  • gases are compressible volumes, they store appreciable energy when pressurized.
  • Liquids however, store little energy upon pressurization because they are relatively noncompressible.
  • the lockhopper is subjected to repeated cyclical stresses, which can ultimately cause mechanical failure in one or more components.
  • Hydraulic lockhoppers also operate more efficiently. It is generally quicker to fill a storage volume with a liquid and raise its pressure than to accomplish the same with a gas.
  • Conventional hydraulic lockhoppers often use liquid filling in both the pressurization and the depressurization cycles of their operation. That is, after discharge of the solids feed material into the reactor vessel, the lockhopper is typically filled with a liquid at the same high pressure as that of the reactor vessel. The lockhopper is then sealed and depressurized. The solids are charged into the liquid filled lockhopper storage volume, or the liquid is emptied and then filled with solids before refilling with liquid. However, failures almost always occur during the pressurization part of the cycle.
  • a preferred solids feed system and method of the invention takes advantage of these facts by pressurizing as a hydraulic lockhopper, but depressurizing as a gas- filled lockhopper, charging with solids, and then pressurizing with liquid.
  • Advantage with respect to speed results, at least in part, from the fact that solids do -76- not have to be charged into a liquid filled lockhopper (a relatively slow process), and the fact that a liquid- filled lockhopper does not have to be drained, only to be refilled again after charging it with solids.
  • the preferred solids feed system of the invention is used to advantage with the reactor of the invention because of the presence of the gas-filled region of the reactor vessel. That is, upon charging conventional reactors with feed solids from a conventional hydraulic lockhopper, liquid is typically displaced into the lockhopper from the reactor, whereas in the system of the present invention, gas is displaced into the lockhopper from the gas receiving region of the reactor.
  • the solids feed system 120 described above and shown in Figure 5 can preferably and advantageously use a modified version of a feed hydraulic lockhopper 122 with modified and advantageous versions of the inlet valve arrangement 124 and the outlet valve arrangement 129.
  • the modified version is preferable because it reduces energy storage during the compression cycle and reduces the cost of maintenance, while increasing the cycling speed, i.e., the speed at which the reactor is charged with feed solids.
  • the modified version also interfaces with the balance of the reactor system in a desirable manner.
  • a preferred embodiment of the modified version of the solids feed system is shown in Figure 10; with two stages of operation shown in Figures 11 and 12.
  • the reactor vessel in Figures 10-12 can be a vessel 20 as described above, and shown in Figure 4, but this is not required.
  • the assembly shown in Figures 10-12 includes a reactor vessel 20 adapted to confine a downwardly moving bed of solids and a countercurrent flow of process liquid and gas, means for operating the reactor vessel at a pressure of at least a first operating pressure, and a solids feed system 600 for charging the reactor vessel with feed solids.
  • the solids feed system 600 consists of a feed lockhopper 602, to which is directed the solids, e.g., carbonaceous solids, through a material feed pipe 604 from a storage bunker 606 (not shown in its entirety) to the entrance 608 of the lockhopper 602.
  • a modified inlet valve arrangement 609 i.e., a first valve arrangement, consists of an upper material flow valve 610 and an upper pressure seal valve 612.
  • the lockhopper upper material flow valve 610 near the entrance 608 of the lockhopper 602, in combination with the upper pressure seal valve 612 delivers feed solids from the material feed pipe 604 into a lockhopper storage receptacle 614.
  • the upper material flow valve 610 is not required to be a pressure valve, and is preferably and typically made from relatively inexpensive materials.
  • An example of a suitable upper material flow valve 610 is a pneumatically operated gate valve made from mild steel.
  • the upper material flow valve 610 is operably positioned so as to protect the upper pressure seal valve 612 from direct communication or contact with feed solids. This does not mean that no feed solids contact the upper pressure seal valve 612, just that a major portion of the feed solids do not come into contact with it and thereby damage it.
  • the upper pressure seal valve 612 is designed to seal the reactor vessel 20, which is at an operating pressure thereof (about 300 to about 2300 psi) from a second lower pressure of the feed pipe 604, which is typically at or near atmospheric pressure. It will be seen from the description of the lockhopper 602 during operation that the storage receptacle 614 is at the operating pressure of the reactor and then, alternately, at a second, lower, pressure such as that of ambient conditions.
  • a valve of existing art can be used for the purpose of sealing the pressure differential between the reactor operating pressure and the second pressure.
  • An alloy ball valve, constructed for rough duty, is preferred for this valve and its designed use.
  • the storage receptacle 614 is constrained by an internal side wall 616 of the lockhopper 602, the upper pressure seal valve 612, and an outlet valve arrangement 617, specifically a lower material flow valve 618 of the outlet valve arrangement 617.
  • the shape of the lockhopper storage receptacle 614 depends upon the flow characteristics of the material.
  • a suitable and preferable shape of the storage receptacle 614 for a material such as coal is substantially cylindrical.
  • the lockhopper storage receptacle 614 is preferably of the same internal diameter 619 as that of the material feed pipe 604, and of a length determined by the flow capacities of the reactor 20.
  • Material flow from the lockhopper storage receptacle 614 is controlled by the outlet valve arrangement 617, which consists of the lower material flow valve 618 and a lower pressure seal valve 620.
  • the lower material flow valve 618 is preferably designed such that the valve body 621 can withstand the pressure differential between the higher operating pressure of the reactor vessel 20 and the lower pressure of outside ambient conditions. It is not necessary, however, for the lower material flow valve 618 to control pressure across its entire valve seal. This is because the lower material flow valve 618 is generally intended only to control the flow of solid material from the lockhopper storage receptacle 614 into the reactor vessel 20.
  • lower material flow valve 618 can be made from relatively inexpensive materials such as mild steel.
  • An example of a suitable valve for the lower flow valve 618 is a pneumatically operated trap-door type valve.
  • the lower pressure seal valve 620 must control pressure across its entire valve seal because it seals off the pressure differential between the reactor vessel operating pressure and the lower, second, pressure of the storage receptacle 614 when it is in its depressurized state, e.g., at or near atmospheric pressure.
  • the lower pressure seal valve 620 is preferably of a similar construction to that of the upper pressure seal valve 612.
  • the lower material flow valve 618 of the lower, i.e., second, valve arrangement 617 is operably positioned so as to protect the lower pressure seal valve 620 from direct communication or contact with feed solids. As with the upper pressure seal valve 612, this means that a major portion of the feed solids are prevented from coming into contact with the lower pressure seal valve 620 and damaging it.
  • the feed lockhopper 602 also consists of a venting system 622 and filling system 624.
  • the venting system 622 consists of a vent line 626, a vent line valve 628, and preferably, an extraction device 630.
  • a preferred embodiment of the venting system 622 consists of a secondary vent line 632, a secondary vent line valve 634, and an extraction device 636 for the secondary vent line 632.
  • the filling system 624 consists of a fill line 638 and a fill line valve 640. The function and operation of the venting system 622 and the filling system 624 are discussed in greater detail below.
  • FIG. 10 shows the stage of operation after the lockhopper storage receptacle 614 has been charged with solids and pressurized with liquid, but before the solids have been transferred to the reactor vessel 20.
  • the material to be fed into the higher pressure zone of the reactor vessel 20 rests in the material feed pipe 604 above the lockhopper upper material flow valve 610, which is closed.
  • the upper pressure seal valve 612 is also closed at the start of the cycle.
  • the lockhopper storage receptacle 614 is generally at the pressure of the reactor vessel 20, and contains gases inherent to the process gas receiving region 96, i.e., the upper part of the reactor vessel 20. During this stage of operation, the storage receptacle 614 is in direct communication with the reactor vessel 20, with the delivery of the feed solids into the reactor vessel 20 having just been completed.
  • the lower material flow valve 618 is open, as is the lower pressure seal valve 620. This orientation of the valves 610, 612, 618, 620 is the same as is shown in Figure 12.
  • the lockhopper storage receptacle 614 of the lockhopper 602 is then sealed off from the reactor vessel 20 by closing the outlet valve arrangement 617 for the lockhopper charging stage of the operation.
  • the lower material flow valve 618 is closed first.
  • a purging spray (not shown in Figures 10-12) is preferably activated to clean the valve seat of the lower material flow valve 618.
  • the lower pressure seal valve 620 is closed, and a purging spray is again activated to advantage to clean the valve seat of the lower pressure seal valve 620.
  • the lower pressure seal valve 620 is closed after the lower material flow valve 618 in an effort to prevent any residual solid material in the storage receptacle 614 from impacting the valve body 641 of the lower pressure seal valve 620.
  • the vent line 626 is located in the upper portion 642 of the lockhopper storage receptacle 614, and is of a relatively small diameter tubing designed for the passage of gases and liquids, when desired, along the direction of arrow 650 out of the lockhopper storage, receptacle 614.
  • the secondary venting line 632 is preferably of slightly larger diameter than the venting line 626.
  • the secondary venting valve 634 can be opened for advantage. Venting can also be aided by extraction devices 630 and 636. Examples of such a device include a blower, or eductor.
  • the secondary venting line 632 is preferably used to lower the pressure in the storage receptacle 614 below that of either ambient pressure or the pressure in the material feed pipe 604, and/or to accelerate the rate of gas venting.
  • the gases vented from the lockhopper storage receptacle 614 are preferably discharged into the process gas stream (described in greater detail above) and/or back into the reactor vessel 20 to control volume and pressure.
  • the secondary vent line 632 is closed, if it was used.
  • the first vent line 626 is left open; however, the destination of the material, which is removed from the storage receptacle 614 along the direction of arrow 650, is preferably switched from the reactor process gas stream to a sump for waste process liquid (not shown in Figures 10-12).
  • the feed lockhopper 602 is then charged with solid feed material 652, e.g., carbonaceous solids,, as shown in Figure 11.
  • the upper pressure seal valve 612 is opened completely.
  • the lockhopper upper material flow valve 610 is opened for a predetermined length of time for charging and then closed.
  • a controlled amount of solid feed material 652 falls into the lockhopper storage receptacle 614 as a result.
  • the lockhopper storage receptacle 614 is filled with the solid feed material 652 to an extent such that a reasonable level is maintained below the upper pressure seal valve 612.
  • An alternative method of charging the lockhopper storage receptacle 614 is to dump a controlled amount of solid feed 652 through the open upper material flow valve 610 using a belt feeder of conventional design (not shown in Figure 11) .
  • the lockhopper storage receptacle 614 is then sealed off from the feed pipe 604 by closing first the upper material flow valve 610 and then the upper pressure seal valve 612.
  • the lockhopper storage receptacle 614 is then filled with liquid and pressurized using the filling system 624, i.e., through the fill line 638 by opening the fill line valve 640.
  • a liquid usually the process water from the reactor vessel 20, is introduced into the lockhopper 602 along the direction of arrow 633.
  • the vent line valve 628 is closed. The lockhopper storage receptacle 614 will then relatively quickly approach the operating pressure of the reactor vessel 20.
  • the pressure in the storage receptacle 614 approximately equals the operating pressure of the reactor vessel minus the pressure of the vertical head between the upper level of the liquid/solids in storage receptacle 614 and an entry point 646 of the lockhopper fill line 638, plus an additional amount of pressure delivered by the process water pressurization pump (not shown in Figure 10 but described above and shown in Figure 5) .
  • the entry point 646 of the fill line 630 can be either above or below the lower material flow valve 618. Alternatively, there may be a plurality of fill lines which could be above, below, or above and below the lower flow valve 618.
  • the fill line 638 penetrates the lockhopper wall 616 slightly above the lower pressure seal valve 620 at the entry point 646. If the entry point 646 is below the lower material flow valve 618, it is desirable to provide some means of leakage of the liquid across the valve 618. Numerous well-known methods are known in the art for this.
  • the lockhopper fill line 638 is closed and the situation exists as shown in Figure 10. Then the lockhopper 602 is discharged (see Figure 12). The lower pressure seal valve 620 is opened first, then the lower material flow valve 618 is opened. Process water spray (not shown), preferably from the same source of liquid as that provided through the lockhopper fill line 638, is activated to facilitate fluidizing the solid feed material 652 stored in the storage receptacle 614. The solids feed material 652 then drops into the reactor vessel 20. The spray is then turned off and the cycle is repeated.
  • Another advantage is the use of additional, relatively inexpensive, valves to protect the pressure seal valves.
  • the pressure seal valves by necessity are expensive, and prone to high maintenance costs due to the need to maintain tight tolerances, and the opportunity for rapid wear. Damaging wear can occur as a result of solid particles being trapped between the sliding pressure sealing surfaces, thus resulting in looser clearances and unacceptable leakages.
  • the rate of wear can be reduced by selective choice of alloys, which can provide for a harder surface.
  • the use of a separate valve to segregate the feed material from contact with the pressure seal valve can -84- substantially reduce the opportunity for particle entrapment upon sealing of the pressure valves.
  • Still another advantage is the use of reactor process liquid, which is already nearly at the pressure required by the lockhopper for equalization. This eliminates the need for pumps of high total developed head, and replaces it with a pump of much smaller requirements.
  • process liquid to fill the lockhoppers also eliminates the entrance of superfluous liquid into the reactor vessel, which improves the process thermodynamics, and reduces waste treatment costs, as discussed above.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)

Abstract

L'invention prévoit des systèmes et des méthodes pour l'enrichissement de matières carbonées de sorte que la valeur calorifique soit élevée, la teneur en humidité soit réduite, et les caractéristiques de manipulation soient améliorées. On prévoit un aménagement de réacteur pour le reformage hydrothermique, une cuve de réacteur étant adapté de manière à limiter un banc de solides carbonés se déplaçant vers le bas et un écoulement contre-courant de liquide de processus. Un aménagement disposé dans une cuve de réacteur préférée définit: une zone inférieure de réacteur de contre-courant dans ladite cuve; une zone de liquide libre disposée dans la cuve du réacteur à un emplacement généralement en-dessus de la zone du réacteur de contre-courant inférieur et en communication de d'écoulement de fluide avec celle-ci; et une zone de solides retenues disposée en-dessus de la zone de réacteur de contre-courant et en communication d'écoulement de solides avec celle-ci, ladite zone de solides retenues étant séparée de la zone de liquide libre.
PCT/US1990/004848 1989-08-29 1990-08-28 Enrichissement accru de matieres carbonees WO1991003530A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU63528/90A AU6352890A (en) 1989-08-29 1990-08-28 Improved beneficiation of carbonaceous materials

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
USNOTFURNISHED 1987-05-22
US40027689A 1989-08-29 1989-08-29
US400,276 1989-08-29

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010092040A1 (fr) * 2009-02-10 2010-08-19 Csl Carbon Solutions Ltd. Procédé hydrothermal pour la préparation d'un matériau de type charbon à partir d'une biomasse et colonne d'évaporation
DE102007012112C5 (de) * 2007-03-13 2016-08-18 Loritus Gmbh Vorrichtung und Verfahren zur hydrothermalen Karbonisierung von Biomasse

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US2966400A (en) * 1954-09-27 1960-12-27 Frances H Lykken Lignite processing method
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US1679078A (en) * 1926-05-14 1928-07-31 Fleissner Hans Method of drying coal and like fuels
US1965513A (en) * 1931-08-21 1934-07-03 Ruzicka Apollo Process for improving coal material
US2610115A (en) * 1948-09-30 1952-09-09 Henry G Lykken Method for dehydrating lignite
US2668099A (en) * 1949-04-11 1954-02-02 Stora Kopparbergs Bergslags Ab Process of dewatering lignocellulosic materials in the production of fuel
US2966400A (en) * 1954-09-27 1960-12-27 Frances H Lykken Lignite processing method
US3552031A (en) * 1968-01-26 1971-01-05 Univ Melbourne Separation of water from solid organic materials
US3729105A (en) * 1971-09-27 1973-04-24 Inst Gas Technology Liquid sealed solids lock hopper
US3992784A (en) * 1974-06-19 1976-11-23 Shell Oil Company Thermal dewatering of brown coal
US4022665A (en) * 1974-12-09 1977-05-10 Institute Of Gas Technology Two phase anaerobic digestion
US4080176A (en) * 1975-11-24 1978-03-21 Shell Oil Company Process for the beneficiation of solid fuel
US4052168A (en) * 1976-01-12 1977-10-04 Edward Koppelman Process for upgrading lignitic-type coal as a fuel
US4129420A (en) * 1976-01-12 1978-12-12 Edward Koppelman Process for making coke from cellulosic materials and fuels produced therefrom
US4127391A (en) * 1976-01-12 1978-11-28 Edward Koppelman Process for making coke from bituminous fines and fuels produced therefrom
US4126519A (en) * 1977-09-12 1978-11-21 Edward Koppelman Apparatus and method for thermal treatment of organic carbonaceous material
US4192650A (en) * 1978-07-17 1980-03-11 Sunoco Energy Development Co. Process for drying and stabilizing coal
US4329156A (en) * 1978-08-02 1982-05-11 Othmer Donald F Desulfurization of coal
US4170456A (en) * 1978-11-22 1979-10-09 Atlantic Richfield Company Inhibiting spontaneous combustion of coal char
US4259083A (en) * 1979-03-22 1981-03-31 Alberta Research Council Production of metallurgical coke from oxidized caking coal
US4247240A (en) * 1979-10-22 1981-01-27 Institute Of Gas Technology Solids feeder having a solids-liquid separator
US4400176A (en) * 1982-04-26 1983-08-23 Atlantic Richfield Company Process for reducing the water content of coal containing bound water
US4486959A (en) * 1983-12-27 1984-12-11 The Halcon Sd Group, Inc. Process for the thermal dewatering of young coals
US4701266A (en) * 1984-04-13 1987-10-20 Hycrude Corporation Solids dewatering apparatus and process
US4579562A (en) * 1984-05-16 1986-04-01 Institute Of Gas Technology Thermochemical beneficiation of low rank coals
US4726810A (en) * 1984-05-23 1988-02-23 Her Majesty The Queen In Right Of The Province Of Alberta As Represented By The Minister Of Energy And Natural Resources Process for the selective agglomeration of sub-bituminous coal fines
US4705533A (en) * 1986-04-04 1987-11-10 Simmons John J Utilization of low rank coal and peat

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007012112C5 (de) * 2007-03-13 2016-08-18 Loritus Gmbh Vorrichtung und Verfahren zur hydrothermalen Karbonisierung von Biomasse
WO2010092040A1 (fr) * 2009-02-10 2010-08-19 Csl Carbon Solutions Ltd. Procédé hydrothermal pour la préparation d'un matériau de type charbon à partir d'une biomasse et colonne d'évaporation

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