The present technology is generally directed to methods of decarbonizing coking ovens, and associated systems and devices.
Coke is a solid carbon fuel and carbon source used to melt and reduce iron ore in the production of steel. To make coke, finely crushed coal is fed into a coke oven and heated in an oxygen depleted environment under closely controlled atmospheric conditions. Such an environment drives off volatile compounds in the coal, leaving behind coke. In some coking plants, once the coal is “coked out” or fully coked, an oven door is opened and the hot coke is pushed from the oven into a hot box of a flat push hot car (“hot car”). The hot car then transports the hot coke from the coke oven to a quenching area (e.g., wet or dry quenching) to cool the coke below its ignition temperature. After being quenched, the coke is screened and loaded into rail cars or trucks for shipment or later use.
Over time, the volatile coal constituents (i.e., water, coal-gas, coal-tar, etc.) released during the coking process can accumulate on the interior surfaces of the coke oven, forming gummy, solidified coking deposits. As used herein, “coking deposit(s)” refers to one or more residual materials that can accumulate within the coke oven, such as, for example, clinkers, ash, and others. Such deposits can have a variety of adverse effects on coke production, including slowing and/or complicating the hot coke pushing operation, decreasing the effective dimensions of the oven, and lowering the thermal conductivity of the oven walls and/or floor. Because of such adverse effects, deposit removal (“decarbonization”) is a mandatory aspect of routine coke oven maintenance in order to maintain coke plant efficiency and yield.
To remove deposits from the coke ovens, oven operation (and, thus, coke production) must be interrupted so that the deposits can be targeted and pushed out of the ovens and into the hot car for disposal. Traditionally, an oven is pulled out of service once every 1-3 years for decarbonization. During those 1-3 years, the deposits have become a near indestructible solid piece of slag that is bound to various interior surfaces of the coke oven, including the floor, sidewalls, and the crown. Much like the hot coke, deposits are extremely hot and exert a large amount of thermal and mechanical stress on the coking machinery. Many conventional coke plants attempt to mitigate damage to the machinery by breaking up large deposits and transporting them to a quench tower for cooling in manageable, smaller portions. However, such an iterative approach takes a long time to remove the waste, thus keeping the ovens/quench tower out of operation and coke production at a halt. In addition, removing the waste in pieces increases the number of transports required of the hot cars, exposing hot cars and/or its individual components to increased amount of thermal and mechanical stress.
The present technology is generally directed to methods of decarbonizing coking ovens, and associated systems and devices. In some embodiments, a method of operating and decarbonizing a coking oven can include inserting a charge of loose coal into the coking oven and heating the coal. The method can further include removing at least a portion of the charge, leaving behind coking deposits in the coking oven. At least a portion of the deposits can be continuously removed from the coking oven. For example, in some embodiments, at least a portion of the deposits can be removed each time a new charge of coal is inserted in the coking oven.
Specific details of several embodiments of the technology are described below with reference to
The oven can receive coal, such as loose, non-stamp-charged coal, from the inlet end 14. The coal can be heated in the coke oven 12 until it is fully coked (typically 24-120 hours). An exit door removing device 20 can be positioned adjacent the outlet end 16 of the coke oven 12 and can remove an exit door of the coke oven 12. After removing the exit door, the door removing device 20 can be moved away from the outlet end 16 of the coke oven 12 along door removal rails 22. A retractable discharge (or “pushing”) ram 18 positioned adjacent to the inlet end 14 of the coke oven 12 pushes the hot coke and/or deposits out of the coke oven 12. In several embodiments, the discharge ram 18 can include a ram head supported and driven by a ram arm. In some embodiments, all or part of the discharge ram 18 is adjustable via a hydraulic system capable of vertical movement. In some embodiments, the discharge ram 18 may include a device for removing an inlet end 14 oven door prior to pushing the coke/deposits out of the coke oven 12. As will be described in further detail below, the discharge ram 18 can include or be coupled to a decarbonization system 50 configured to remove the coke deposits 26 from the coke oven 12. In further embodiments, the decarbonization system 50 and coke-charging aspects of the system can each use separate, dedicated retractable rams.
In some embodiments, the decarbonization system 50 can provide high-pressure removal of the coke deposits 26 from the coke oven 12. For example, in some embodiments, as will be discussed in more detail below, the decarbonization system 50 can include various scoring and/or scraping features to break up the compacted deposits and/or remove the deposits from the oven. In some embodiments, the deposits 26 can be broken up and/or removed continuously. As used herein, the term “continuously” is used to indicate a routine breaking or removal of the deposits that occurs on a schedule more frequently than traditional annual oven cleaning. For example, continuous removal can indicate that the deposits 26 are removed from the coke oven 12 at least monthly, weekly, daily, or each time a new charge of coal is inserted in the coke oven 12, such as before, during, or after the charge is inserted or removed.
A hot car 24 can be positioned adjacent to the outlet end 16 of the coke oven 12 for collection of hot coke and/or deposits 26 pushed from the oven by the discharge ram 18. The “hot car” may comprise a flat push hot car, train, and/or a combined flat push hot car/quench car. Once the hot coke or deposits 26 are loaded onto the hot car 24, the car 24 can be transported on rails 28 to a quench car area 30. In the quench car area 30, the hot coke slab or deposits 26 on the hot car 24 can be pushed by a stationary pusher 32 onto a quench car 34. Once the quench car 34 receives the hot coke or deposits 26, the quench car 34 can be positioned in a quench station 36 wherein the hot coke or deposits 26 can be quenched with sufficient water to cool the coke or deposits 26 to below a coking temperature. Various embodiments may use a combined hot car/quench car that allows the hot coke or deposits 26 to be transported directly from the coke oven 12 to the quench station 36 using a single hot car. The quenched coke can then be dumped onto a receiving dock 38 for further cooling and transport to a coke storage area.
In some embodiments, the couplers 258 are movable to allow the scraping plate 252 to vertically adjust to follow the contour of the oven floor. For example, in some embodiments, the couplers 258 can include a spring-loaded or hydraulic feature to provide scraping plate 252 adjustability. In further embodiments, the couplers 258 can be fixed to prevent such adjustability. In some embodiments, if the oven floor is not level, the scraping plate 252 can ride over high points and fill in low points with deposits, providing the benefit of keeping a thin, protective, and lubricating layer of clinker or other deposits on the floor.
Embodiments of the decarbonization system 470 may be provided with one or more scraping plates 452 having a wide array of different configurations. For example, a scraping plate 452, coupled with the coupler 466, may be provided with a pair of beveled edges 454, positioned at opposite end portions of the scraping plate 452. In this manner, a beveled edge 454 defines a leading edge portion of the scraping plate in either direction that the decarbonization system 470 is moved along a length of the oven. In some embodiments, the pair of beveled edges 454 may be provided with lengths that are equal or dissimilar to one another. Embodiments of the scraping plates 452 may present the beveled edges 454 to extend upwardly from a generally horizontal base plate of the scraping plate 452 at an angle approximating forty five degrees. However, other embodiments may present the beveled edges to extend upwardly at an angle that is at least slightly less than or greater than forty five degrees. Similarly, embodiments of the scraping plates 452 may include chamfered or rounded edges where the beveled edges 454 meet the horizontal base plate, depending on the desired level of ease with which the scraping plates 452 engage edges or irregular surfaces of the coking deposits and the oven floor.
The decarbonization system 550 can further include a weight or ballast 556 configured to weigh down the decarbonization system 550 against the coke oven floor. In various embodiments, the ballast 556 can be coupled to a pushing ram (e.g., the pushing ram head 518 or other portion of a pushing ram) or the scraping plate 552. In further embodiments, there can be more or fewer ballasts 556. In particular embodiments, the ballast 556 comprises steel, a steel alloy, or other refractory materials. In some embodiments, the pushing ram head 518 or scraping plate 552 can be uniformly or non-uniformly weighted to achieve consistent or varied downward pressure as desired.
The decarbonization system 650 further includes various scoring features to create grooves or breaks in the coking deposits. For example, in the illustrated embodiment, the decarbonization system 650 includes scoring teeth 670 along a bottom surface of the scraping plate 652 and a scoring bar 672 extending outward and downward from the pushing ram head 618. The teeth 670 and bar 672 can groove or score the surface of the coke, leading to fractures that break apart the highly-compacted deposits into more easily removable pieces. In still further embodiments, other scoring features such as a wheel, impactor, cutter, etc. can be used.
In some embodiments, the deposits having been broken apart by the scoring features can be more readily pushed or otherwise removed from the coke oven. In various embodiments, the scoring features can be used in conjunction with pushing the deposits from the oven, or can be used separately. For example, in some embodiments, the deposits can be scored each time the deposits are scraped from the oven. In further embodiments, scoring the deposits can occur more frequently than scraping the deposits because the scoring reduces the need for high-pressure scraping. In other embodiments, scoring the deposits can occur less frequently than scraping the deposits. In still further embodiments, a scoring feature may be coupled to a coke pushing ram while the scraping plate 652 is coupled to a separate decarbonization pushing ram that follows the coke pushing ram.
The scoring features can be positioned on a pushing and/or following side of the pushing ram head 618, the scraping plate 652, on another device altogether (e.g., a pushing ram arm), or in a combination of these positions. Further, various embodiments can include scoring features across (or partially across) the width and/or depth of the pushing ram head 618. Additionally, various scoring features may be used individually or in combination. For example, while the decarbonization system 650 includes both scoring teeth 670 and a scoring bar 672, in further embodiments, only one of these scoring features (or other scoring features) may be used.
The decarbonization system 750 can further include an optional weight or ballast 756 to pressure the pushing ram head 718 and scraping plate 752 downward against the floor to improve contact and deposit clean-out. For example, in the illustrated embodiment, the ballast 756 is shown coupled to the pushing ram head 718. In further embodiments, one or more ballasts 756 can additionally or alternately be coupled to the pushing ram arm 719, the scraping plate 752, or can be integral to any of these features. Some example locations for alternate or additional placement of the ballasts 756 are shown in dashed lines.
The decarbonization system 850 can further include a plurality of rollers (e.g., an upper roller 860 and lower rollers 862) attached to a pushing support structure (e.g., a pushing/charging machine, not shown) that is configured to support and allow for retractable movement of the pushing ram arm 819. In addition, or as an alternative to the weight systems described above which encourage contact between the scraping plate 852 and the oven floor, in some embodiments, the rollers 860, 862 can be adjusted to provide a generally similar force. For example, the upper roller 860 can be adjusted upward and/or the lower rollers 862 can be adjusted downward (in the direction of the arrows) to add downward force to the cantilevered pushing ram head 818 and/or scraping plate 852. The same relationship can apply regardless of whether the scraping plate 852 is attached to the pushing ram head 818 as shown or directly to the pushing ram arm 819 as shown in
The scraper 1000 further includes a plurality of elongated scraper shoes 1010 coupled to the scraper body 1002 so that the scraper shoes 1010 are horizontally spaced apart from one another. In various embodiments, the scraper shoes 1010 extend rearwardly and perpendicularly from the scraper body 1002. The scraper shoes 1010 include scraping skis 1012 that include a generally rigid surface made, for example, of steel, steel alloy, ceramic, or other refractory materials that are suitable for scraping or otherwise pushing coking deposits from a coke oven. As with the scraping plate, the rigid surface of the scraping skis 1012 may include one or more various grooves or scraping projections presented in one or more different scraping patterns and may be covered or at least partially embedded with abrasive materials, including ceramics, aluminum oxides, rubies, sapphires, diamonds, and the like. In some embodiments, the scraping skis 1012 have a vertical thickness from about 0.25 inch to about 3 inches, and in particular embodiments, has a thickness of about 0.75 inch. The scraping skis 1012 include a forward beveled edge (not depicted) and a rearward beveled edge 1014. The forward beveled edge and rearward beveled edge 1014 may extend upwardly from the bottom of the scraping skis 1012 at various angles according to the intended scraping operations. In the depicted embodiment, the forward beveled edge and rearward beveled edge 1014 extend upwardly from the base of the scraping ski at forty-five degree angles. With reference to
In various embodiments, bottom surfaces of the scraping skis 1012 are positioned to be co-planar with one another. In some embodiments, the bottom surfaces of the scraping surfaces 1012 are positioned to be co-planar with a bottom surface of the scraper body 1002. In such instances, the scraper 1000 has a uniform bottom surface and any weight received by the coke oven floor from the scraper 1000 is evenly disbursed across the coke oven floor 64.
In various embodiments, the scraping can be performed using any of the decarbonization systems described above. For example, in some embodiments, the scraping includes using a scraper having at least one rounded or beveled edge proximate to the coke oven floor. In further embodiments, the scraping includes using a scraper having one or more plates that substantially follow a contour of the coke oven floor during scraping. In particular embodiments, the scraper is at least partially made of steel, a steel alloy, or a ceramic material. In some embodiments, the scraping is performed by a scraper including a ram head having a ballast coupled thereto. In some embodiments, the method 1300 can further include scoring a surface of the deposits using any scoring feature such as those described above.
The following Examples are illustrative of several embodiments of the present technology.
1. A method of decarbonizing a coke oven of coking deposits, the method comprising:
2. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping at least a portion of the coking deposits with a scraper operatively coupled to a pushing ram.
3. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper having at least one rounded or beveled edge adjacent at least one interior surface of the coke oven.
4. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper having one or more plates that substantially follow a contour of at least one of the interior surfaces of the coke oven during scraping.
5. The method of example 1, further comprising scoring a surface of the coking deposits.
6. The method of example 1 wherein removing coking deposits from the coke oven comprises running a scraper along at least one interior surface of the coke oven a single time, whereby the scraper is pushed along a length of the coke oven and then retracted along the length of the coke oven.
7. The method of example 1 wherein removing coking deposits from the coke oven comprises running a scraper over at least one interior surface of the coke oven a plurality of times.
8. The method of example 7 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of at least one deformably resilient scraping feature that substantially follows a contour of at least one of the interior surfaces of the coke oven during scraping.
9. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of steel, a steel alloy, or ceramics.
10. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of an abrasive.
11. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper operatively coupled to a pushing ram head of a pushing ram.
12. The method of example 11 wherein a weight is operatively coupled with the pushing ram.
13. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper operatively coupled to a pushing ram arm of a pushing ram.
14. The method of example 13 wherein a weight is operatively coupled with the pushing ram.
15. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping coking deposits from a plurality of interior surfaces of the coke oven with a plurality of scrapers operatively coupled to a pushing ram.
16. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of at least one deformably resilient scraping feature that substantially follows a contour of at least one of the interior surfaces of the coke oven during scraping.
17. The method of example 16 wherein the at least one deformably resilient scraping feature includes a plurality of elongated bristles operatively coupled to a pushing ram such that free end portions of the bristles are directed toward the at least one interior surface of the coke oven.
18. The method of example 16 wherein the at least one deformably resilient scraping feature includes at least one elongated scraping bar operatively coupled to a pushing ram with at least one resiliently deformable hinge such that a leading edge portion of the at least one elongated scraping bar is positioned adjacent to the at least one interior surface of the coke oven.
19. The method of example 16 wherein the scraper includes a plurality of deformably resilient scraping features that substantially follow contours of a plurality of the interior surfaces of the coke oven during scraping.
20. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a plurality of scrapers operatively coupled with a pushing ram.
21. The method of example 20 wherein the plurality of scrapers include at least two elongated scrapers operatively coupled with a pushing ram such that the elongated scrapers are positioned to be side by side one another with lengths of the scrapers extending perpendicular to a length of the coke oven during scraping.
22. The method of example 21 wherein the elongated scrapers are positioned to be coaxially aligned with one another and horizontally spaced apart to define a gap between the elongated scrapers.
23. The method of example 22 wherein the scraper includes a plurality of deformably resilient scraping features that extend outwardly from the elongated scrapers into the gap between the elongated scrapers.
24. The method of example 23 wherein the plurality of deformably resilient scraping features from the adjacent elongated scrapers intermesh with one another in the gap between the elongated scrapers.
25. The method of example 22 wherein the scraper includes a third elongated scraper operatively coupled with the pushing ram rearwardly from the at least two elongated scrapers and positioned so that a length of the third elongated scraper is behind the gap between the elongated scrapers to engage coking deposits that pass through the gap during scraping.
26. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of at least one deformably resilient scraping feature that substantially follows a contour of the crown of the coke oven during scraping.
27. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping the coking deposits with a scraper comprised of at least one deformably resilient scraping feature that substantially follows a contour of the sidewalls of the coke oven during scraping.
28. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping coking deposits on the floor of the coke oven wherein a flattened layer of coking deposits remains on the floor of the coking oven after scraping.
29. The method of example 1 wherein removing coking deposits from the coke oven comprises scraping at least a portion of the coking deposits with a scraper operatively coupled to a pushing ram; the scraper including an elongated scraper body extending perpendicular to a length of the coke oven during scraping and a plurality of elongated scraper shoes coupled to the scraper body so that the scraper shoes are horizontally spaced apart from one another and extending parallel to the length of the coke oven during scraping.
30. The method of example 29 wherein the plurality of scraper shoes include soles that are co-planar with one another and vertically spaced beneath a plane in which a sole of the scraper base resides, whereby a substantial portion of a scraper weight received by the coke oven floor is received beneath the soles of the scraper shoes during scraping.
31. The method of example 30 wherein the plurality of scraper shoes are positioned along a length of the scraper body so that the scraper shoes are positioned above, and aligned with, sole flue sole flue walls beneath the oven coke floor during scraping.
32. A coking system, comprising:
33. The system of example 32 wherein the decarbonization system is operatively coupled to the pushing ram.
34. The system of example 32 wherein the decarbonization system comprises a scraper having at least one rounded or beveled edge proximate at least one of the interior surfaces of the coke oven.
35. The system of example 34 wherein the decarbonization system comprises a scraper having at least one weight coupled thereto.
36. The system of example 32 wherein the decarbonization system comprises a scraper having one or more scraping features that substantially follow a contour of one or more interior surfaces of the coking oven.
37. The system of example 32 wherein the decarbonization system is comprised of steel, a steel alloy, or ceramics.
38. The system of example 32 wherein the decarbonization system is comprised of an abrasive.
39. The system of example 32 wherein the decarbonization system is operatively coupled to a pushing ram head of a pushing ram.
40. The system of example 39 wherein a weight is operatively coupled with the pushing ram.
41. The system of example 32 wherein the decarbonization system is operatively coupled to a pushing ram arm of a pushing ram.
42. The system of example 41 wherein a weight is operatively coupled with the pushing ram.
43. The system of example 32 wherein the decarbonization system is comprised of at least one deformably resilient scraping feature that is configured to substantially follow a contour of at least one of the interior surfaces of the coke oven during a scraping movement.
44. The system of example 43 wherein the at least one deformably resilient scraping feature includes a plurality of elongated bristles operatively coupled to a pushing ram such that free end portions of the bristles are directed toward the at least one interior surface of the coke oven.
45. The system of example 43 wherein the at least one deformably resilient scraping feature includes at least one elongated scraping bar operatively coupled to a pushing ram with at least one resiliently deformable hinge such that a leading edge portion of the at least one elongated scraping bar may be selectively positioned adjacent the at least one interior surface of the coke oven.
46. The system of example 32 wherein the decarbonization system is comprised of a plurality of scrapers operatively coupled to a pushing ram.
47. The system of example 46 wherein the plurality of scrapers include at least two elongated scrapers operatively coupled with a pushing ram such that the elongated scrapers are positioned to be side by side one another with lengths of the scrapers extending perpendicular to a length of the pushing ram.
48. The system of example 47 wherein the elongated scrapers are positioned to be coaxially aligned with one another and horizontally spaced apart to define a gap between the elongated scrapers.
49. The system of example 48 wherein the scraper includes a plurality of deformably resilient scraping features that extend outwardly from the elongated scrapers into the gap between the elongated scrapers.
50. The system of example 49 wherein the plurality of deformably resilient scraping features from the adjacent elongated scrapers intermesh with one another in the gap between the elongated scrapers.
51. The system of example 48 wherein the scraper includes a third elongated scraper operatively coupled with the pushing ram rearwardly from the at least two elongated scrapers and positioned so that a length of the third elongated scraper is behind the gap between the elongated scrapers.
52. The system of example 32 wherein the decarbonization system is comprised of at least one deformably resilient scraping feature that is positioned to extend upwardly from the decarbonization system and adapted to substantially follow a contour of the crown of the coke oven.
53. The system of example 32 wherein the decarbonization system is comprised of at least one deformably resilient scraping feature that is positioned to extend outwardly from side portions of the decarbonization system and adapted to substantially follow a contour of the sidewalls of the coke oven.
54. The system of example 32 wherein the decarbonization system is operatively coupled to a pushing ram; the decarbonization system including an elongated scraper body extending perpendicular to a length of the pushing ram and a plurality of elongated scraper shoes coupled to the scraper body so that the scraper shoes are horizontally spaced apart from one another, extending parallel to the length of the pushing ram.
55. The system of example 54 wherein the plurality of scraper shoes include soles that are co-planar with one another and vertically spaced beneath a plane in which a sole of the scraper base resides.
The present technology offers several advantages over traditional decarbonization systems and methods. For example, traditional decarbonizing takes places very sporadically, causing a large amount of deposits to build up on the oven floor and reducing coke plant efficiency and yield. The present technology provides for regular removal of coking deposits to allow coke production to continue, allow the coke plant to maintain a constant oven volume, and give the plant a higher coke yield. Moreover, by continuously decarbonizing the ovens, less thermal and mechanical stress is put on the coking equipment that would traditionally suffer a large amount of wear during the sporadic decarbonizing. Further, the continuous scraping systems described herein can cause uneven coke oven floors to become level and smooth for easier coal pushing.
From the foregoing it will be appreciated that, although specific embodiments of the technology have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the technology. For example, while several embodiments have been described in the context of loose, non-stamp-charged coal, in further embodiments, the decarbonization systems can be used in conjunction with stamp-charged coal. Additionally, while several embodiments describe the decarbonization performed on an oven floor, in further embodiments, other surfaces of the ovens, such as the walls, can be decarbonized. Further, certain aspects of the new technology described in the context of particular embodiments may be combined or eliminated in other embodiments. Moreover, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein. Thus, the disclosure is not limited except as by the appended claims.
This application claims the benefit of U.S. Provisional Patent Application No. 61,922,614, filed Dec. 31, 2013, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61922614 | Dec 2013 | US |