CONTINUOUS-LINE PASSIVATION STRUCTURE FOR DESULFURIZED COAL

Abstract: Apparatus for treatment of pulverant desulfurized coal to economically passivate sites from which sulfur has been extracted by treatment with a fluid passivating agent in a continuous-line operation. A longitudinally-extended travel path is established for the pulverant coal. The direction of movement of the coal is changed along such travel path, without requiring pneumatic impulsion or mechanical drives, so as to expose all surfaces of the pulverant coal to treatment. The fluid passivating agent is injected at multiple levels (60-63) along the treatment path; such injection levels are coordinated in placement and number with baffles (30-33) which effect angular changes in direction of movement of the pulverant coal with respect to the longitudinally-extended downward direction travel path of such coal.

Description: CONTINUOUS-LINE PASSIVATION STRUCTURE FOR DESULFURIZED COAL • This invention relates to treatment of pulverant solids with fluid materials. More particularly, this in¬ vention is concerned with apparatus for treatment of pulverant coal while moving in a continuous-line operation, ' after extraction of sulfur, to inhibit reabsorption of sulfur by the coal. Coals from various geographical regions have sulfur contents which, during burning, produce sulfur dioxide in amounts asserted to be a major contributor to acid rain. Various approaches have been disclosed for reducing sulfur dioxide ' in the discharge gases resulting from the combustion of coal. ■ Included in these approaches are desulfurization treatments for decreasing the sulfur content of raw coal to governmental and industry standards so as to qualify as "compliance" coal. Chemical reactions for extracting sulfur from coal and conversion of extracted sulfur to sulfur compounds which are readily removable from the coal are disclosed in copend¬ ing U.S. application Serial No. 223,274, entitled "REMOVING SULFUR AND BENEFICIATING COAL", filed January 8, 1981 and in the continuous-line operation disclosure of copending appli¬ cation Serial No. PCT/ , entitled "CONTINUOUS-LINE OPERATIONS FOR DESULFURIZING COAL", filed concurrently OMPI herewith; the disclosures of such copending applications are incorporated herein by reference. It has been discovered that the sites from which sulfur has been extracted are very active chemically and tend to reabsorb sulfur from surrounding environments encountered after processing. The present invention pro¬ vides apparatus for economic treatment of desulfurized pulverant coal to passivate such chemically active sites. A significant contribution involves passivation treatment of all surfaces of pulverant desulfurized coal in a continuous—line operation without requiring moving parts or energy-consuming drive means. Other advantages and con¬ tributions of the continuous-line apparatus of the present invention are set forth in describing the specific embpdi- ment shown in the accompanying drawings. In these drawings: FIG. 1 is a schematic view, with portions cut away and portions shown in dotted lines, of apparatus embodying the invention? and FIG. 2 is an elevational view of a portion of the apparatus of FIG. 1. In FIG. 1, feed conveyor 10 delivers pulverant coal into passivation chamber 12 and conveyor 14 delivers passivated coal, after passage through passivation chamber 12 for stockpiling. A vertically-oriented longitudinally-extending enclosure is provided which can be at least partially open to ambient atmosphere at its charge and discharge ends for work product. An elongated confinement path for movement and treatment of work product is defined largely by side- walls 16, 17 and 18, 19 (FIG. 2) which are vertically oriented. An entrance chute portion 20 circumscribes a por¬ tion of feed conveyor 10 for receiving pulverant coal and includes top closure wall 22. Pulverant coal is delivered by conveyor 10 for downward movement along the elongated confinement path, as indicated, toward a bottom discharge opening 26 (FIG. 2) contiguous to conveyor 14. These structures are arranged so that pulverant coal requires neither pneumatic impulsion nor mechanical drive means for movement through passivation chamber 12. Baffle means are provided along the confinement path and include a plurality of individual baffles 30, 31, 32, and 33 extending in angled relationship into such elon¬ gated travel path for work product. Such individual baffles are vertically spaced along the elongated confinement path . with each having an upper contact surface which is down¬ wardly sloped, preferably with an angle of about 55° between such surface and the horizontal for receiving downwardly falling pulverant coal. These baffles change the direction of movement of pulverant coal in the confinement path expos- ing all surfaces of the coal. Pulverant coal delivered by conveyor 10 falls onto baffle 30. The pulverant coal rolls downwardly off baffle 30 at distal end 36 toward baffle 31. The pulverant coal contacts the upper surface of baffle 31 and rolls down- wardly off distal end 37; the pulverant coal continues in this zig-zag pattern, being directed to baffle 32, off distal end 38, onto baffle 33, and off distal end 39 for exit a ' t discharge opening 26 onto conveyor 14. As disclosed in the above-identified copending applications, a passivating agent for chemically active sites from which sulfur has been removed includes carbon dioxide which can be provided in the form of carbolic acid. The present invention provides repeated impinge¬ ment of passivat.ing agent, and extended contact, with the pulverant coal along substantially the full travel path within the passivating chamber. In accordance with the invention and, as shown in FIG. 1, passivating agent injec¬ tion means are spaced vertically along the confinement path. Individual injectors are distributed in juxtaposition to each of the distal ends of the baffles to contact pulverant coal with passivating agent on all its surfaces without impeding forward movement of work product. For this purpose passivation agent is injected at an angle transverse to the continuous-line direction of movement and avoiding an upward component of injection which would significantly impede downward rate of movement of the work product. The vertically-spaced positions of injectors are shown in FIG. 1 and injector discharge patterns are shown in dotted lines. Injector 40 is located to inject passiva¬ ting agent to contact pulverant coal falling from distal end 36 of baffle 30; injector 41 is positioned to contact pul- verant coal falling from distal end 37 of baffle 31; injector 42 is positioned to impinge passivating agent on pulverant coal falling from distal end 38 of baffle 32;- and, injector 43 is positioned to impinge passivating agent on pulverant coal falling from distal end 39 of baffle 33 enroute to discharge opening 26. As- shown in FIG. 2, injection manifolds are vertic ally spaced to provide a plurality of injection outlets for passivating agent at the selected vertically spaced levels along the pulverant coal travel path. The Opening for con- veyor 10 is shown in dotted lines at 50. From entrance chute portion 20, the cross-sectional area of passivating chamber is decreased by portions of sidewalls 54, 56 which provide a decreasing cross section enabling use of a rela¬ tively narrow-width belt, compared to that of feed conveyor 10, for accumulating passivated coal. Manifold 60 directs passivating agent from a plurality of ' injectors to impinge on pulverant coal as the coal rolls from the distal end of the first baffle; manifold 61 is at a second downwardly spaced level, manifold 62 is at a third downwardly spaced level, and manifold 63 is located contiguous to discharge end 26. The pulverant coal is contacted on all its surf¬ aces during its downward movement to passivate the sites from which sulfur has been removed. The structure is pre¬ sented so as to accomplish such contact without impeding desired movement of coal in continuous-line operations. Belt 66 of feed conveyor 10 is selected to spread the pulverant coal in a laterally-wide shallow-depth pattern so that the coal has a shallow depth dimension in confront¬ ing the direction of injection of passivating agent. The cross-sectional configuration at the entry portion of the passivation chamber accommodates such laterally-wide feed pattern. For example, the conveyor feeds into the wide dimension of the entrance chute to accommodate the wide lateral dimension of the feed conveyor belt; passivating agent injection penetrates the shallow depth dimension of the coal. In a typical embodiment for handling up to about 250 tph of pulverant coal, belt 66 has a lateral dimension of about four feet, or more. As viewed in FIG. 2, entrance chute 20 has a width dimension of about five feet when a four-foot feed conveyor belt is used. The chamber, as viewed in FIG. 1, has a depth dimension of about three feet. This depth can remain about the same along the longitudinal travel path with portions of the sidewalls 18, 19 gradually decreasing the lateral cross section, as shown in FIG. 2, to about two feet. The entrance cross-sectional opening should typically be about fifteen square feet and the discharge cross-sectional opening should be about six square feet for piling the passivated pulverant coal .on a discharge conveyor belt having about 'half the lateral dimension of feed conveyor ' belt 66, e.g. twenty-four to thirty inches. The overall height of the passivation zone is about ten feet with the manifolds distributed between the entrance opening and the discharge end at about two- foot intervals. Such structure will accommodate continuous- line movement rates up to about two hundred and fifty tons per hour. At such rate, about fifty gallons per hour of carbonated water containing about six percent CC would be utilized; this comprises about .001% by weight of the treated coal. While specific configurations and orientations have been set forth in disclosing concepts of the invention and describing a working embodiment, in the light of such teachings those skilled in the art can make modifications> such as changing the zig-zag pattern of descent, without departing from the inventive concept; therefore, in deter¬ mining the scope of the present invention, reference should be had to the accompanying claims.

Claims: CL IMS 1. Apparatus for passivation treatment of pulverant coal with a fluid passivating agent during continuous-line movement of the pulverant coal, comprising vertically-oriented longitudinally-extended enclosure means having • a charge opening for pulverant coal contiguous to its upper longitudinal end, a discharge opening -for pulverant coal located contiguous to its lower longitudinal end, and sidewall means defining an elongated vertically- oriented confinement path providing for downward movement of pulverant coal through such enclosure means free of any requirement for pneumatic impulsion or mechanical drive means,- baffle means located within such confinement path defined by the sidewall means including a plurality of individual baffles which extend in angled relationship into such confinement path for movement of pulverant coal, such plurality of individual baffles being located in vertically-spaced relationship along such confinement pat including a final baffle contiguous to such discharge open- ing, such individual baffles each presenting a down- wardly inclined surface for receiving pulverant coal and changing its direction of movement during its travel down- wardly through the enclosure means, each such individual baffle with the exception of such final baffle directing such pulverant coal onto a subsequent vertically-spaced baffle for continued downward travel, means for introducing a passivating agent into such enclosure, such means including injection means located in vertically-spaced relationship along such enclosure means to discharge passi- vating agent onto pulverant coal moving downwardly from such individual baffles during travel along such confinement ■ path. 2. The apparatus of claim 1 in which successive levels of vertically-spaced baffles extend from opposing directions into such confinement path to establish a zig-zag pattern of change of direction for pulverant coal during its downward' movement through the enclosure means. - 3. The apparatus of claim 1 in which the down- wardly inclined pulverant coal contact surface of the individual baffles is angled downwardly at about 55° from the horizontal. 4. The apparatus of claim 1 including at least one injector being located to direct passivating agent to contact pulverant coal moving from a baffle surface at each such vertically spaced level. 5. The apparatus of claim 1 in which the injec- . tion means inject passivating agent to have a horizontal component transverse to the downward direction of movement of pulverant coal at multiple levels corresponding to loca- tion levels of the vertically-spaced individual baffles to impinge on pulverant coal falling from distal ends of indi- vidual.baffles. 6. The apparatus of claim 5 in which the passivat- ing agent injection means at the multiple levels include a manifold with a plurality of injectors at each such level. 7. The apparatus of claim 1 including in cαmbina- tion feed conveyance means for delivering pulverant coal along-a longitudinal direction into such enclosure means for downward travel through such enclosure means, and discharge conveyance means for delivering pulverant coal in a- longitudinal direction after passivation treatment. 8. The apparatus of claim 6 in which the cross- sectional configuration of the entrance opening and confine- ment travel path accommodate a feed pattern for pulverant coal which is of shallow depth in lateral cross section transverse to such longitudinal direction of feed into such enclosure means. 9. The apparatus of claim 7 in which the feed conveyance means comprises a feed conveyor belt and in which such discharge conveyance means comprises a ^JR£4 OMPI discharge conveyor belt, such feed conveyor belt having a lateral dimension approaching twice the lateral dimension of the discharge conveyor belt. OMPI

Inventors: CHAPPELL MARTIN L, CHINNICI ANTHONY J, GROVE F ALLEN, LARUE PHILIP R, CHAPPELL, MARTIN, L., CHINNICI, ANTHONY, J., GROVE, F., ALLEN, LARUE, PHILIP, R.
Applicants: CHAPPELL MARTIN L, CHINNICI ANTHONY J, GROVE ALLEN F, LARUE PHILIP R, CHAPPELL, MARTIN, L., CHINNICI, ANTHONY, J., GROVE, F., ALLEN, LARUE, PHILIP, R.
Application year: 1981
Main classification: B01F3
IPC codes: B01F5, C10L9