Pressure controller for a coke box

Abstract

A pressure controller for a coke box has a fan assembly and a valve assembly selectively coupling the fan assembly to the coke box. A barometer senses a pressure level in the coke box. A control element controls a speed of the fan assembly to maintain the pressure level in the coke box below a desired pressure level.

Description

FIELD OF THE INVENTION

[0002] The invention is generally related to coke ovens for steel production, and more particularly to pushing coke out of a coke oven and into a box sealed to the oven during the push, and particularly to controlling pressure in the box.

BACKGROUND OF THE INVENTION

[0003] When coal is heated at very high temperature in ovens in the absence of oxygen, the heat drives the volatile gases from the coal to form coke, which is essentially pure carbon. The coke is then used as a fuel and oxidizer in blast furnaces to remove oxygen from iron ore to produce iron. After the coal has been turned into coke in the oven by the “coking process,” the coke must be pushed out of the oven for cooling before being sized for use in the blast furnaces. In conventional coking operations, the hot coke is pushed from the oven by a ram. The coke then drops into a quench car that is open to the atmosphere. As the hot coke falls into the quench car, a large volume of particulate matter escapes. Conventional practice is to use large fans the suck air containing the particles into a bag house where the larger or the particles are captured. The smaller particles can pass through small holes that are required in the filter bag to let air pass through the filter. These smaller particles are hazardous to humans and can be absorbed into the bloodstream.

[0004] As the hot coke emerges from the oven, it falls into the quench car and travels to a quench tower that is located beyond a battery of ovens. The coke ignites with the atmospheric oxygen and continues burning until the hot coke is quenched. Ash is created on the surface of the coke as it burns. This ash is washed off the coke by quench water which turns to steam and carries the ash particles up the quench tower. It is difficult to capture this ash before it enters the atmosphere. When the quench car containing the hot coke is positioned under the quench tower, thousands of gallons of water are sprayed over the hot coke in order to lower the coke temperature below the kindling temperature. Approximately one third of the water turns into steam. Most of the steam travels up through the quench tower which is designed to cool some steam back to water and to collect the particulate matter and ash that is carried by the steam. The water containing the particular matter circulates through the coke in the quench car and into a quench pond where the large particles will have time to settle out. However, the very small particles, if caught in the quench tower water the first time through, will not have time to settle out and will eventually escape into the atmosphere as the water in the quench pond is circulated through the quench tower time and time again.

[0005] The above are environmental problems. However there are many Commercial problems that result from the above-mentioned conventional pushing and quenching systems. Pushing and dropping the hot coke into the hopper cars can weaken and break the semi-rigid coke into chunks that are often smaller than the minimum acceptable size for use in a blast furnace operation. Other problems are that the burning coke causes a loss of valuable coke.

[0006] Quenching the burning coke with large quantities of water creates additional problems. For example, a major disadvantage with water quenching is that the wet coke has a lower heating value than dry coke but more importantly it is difficult to keep the moisture content of the coke constant. If this is not done, the blast furnace cannot be run efficiently. Finally, the quenching operation, which causes very rapid temperature change, causes the coke to develop internal cracks, further degrading the quality and strength of the coke.

[0007] All of these problems are alleviated or eliminated by coke handling apparatuses that utilize what is known as a coke box. Other problems are reduced or eliminated by using a coke box with a carrier vehicle. Such coke boxes and carrier vehicles have been invented by the assignee of the present invention, the Kress Corporation. Among others, U.S. Pat Nos. 4,285,772; 4,886,580; 4,997,527; 5,190,617; and 5,192,398, each assigned to the Kress Corporation, disclose such coke boxes and carrier vehicles. These patents generally disclose a system employing a trackless, steerable vehicle that is adaptable for either grass roots coking operations or existing coke oven batteries.

[0008] Numerous attempts have also been made by others to overcome some or all of these problems associated with conventional wet quenching, including some dating back to the 19th century. Approaches have included receiving the coke in substantially cake form, followed by other direct or indirect water quenching, such as is disclosed, for example, in the above mentioned Kress Corporation U.S Pat. No. 4,285,772. There have also been proposals involving the use of inert cooling gas to quench hot coke within closed containers, such as coke boxes and silos. This is also disclosed, for example, in the same Kress patent.

[0009] Problems can also arise when utilizing a coke box to quench the hot coke material. For example, when placing coke in the coke box, the entering coke displaces any gases, including ambient air, in the box. As the ambient air is displaced, it must pass over the hot coke which increases the air temperature and, thus, the volume of the now hot air expands up to four (4×) times. Due to the small area available for the gas to pass around the coke within the box, the air and/or gases are moved at relatively high velocity back over the coke. The high velocity moving air can pick up small particulate which cannot be contained and which can escape up the ascension tubes in the top of the oven or out of the pusher side of the oven. There is also a small amount of burning that will take place as oxygen in the ambient air in the empty box passes back over the hot coke. The present invention addresses all of these problems.

Brief Description of the Drawings

[0010] An exemplary controller and method in accordance with the teachings of the present invention is described and explained in greater detail below with the aid of the drawing figures in which:

[0011] FIG. 1 is a plan view of an exemplary coke box suitable for use in accordance with the teachings of the present invention.

[0012] FIG. 2 is a side elevation view of the coke box shown in FIG. 1.

[0013] FIG. 3 is an end view of a suction fan arrangement and a pressure detector for controlling pressure in the coke box and constructed in accordance with the teachings of the present invention.

[0014] FIG. 4 is a plan view of the arrangement of FIG. 3 but showing the suction fan disconnected from the closed check valve on the coke box.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An improved means is disclosed for controlling the internal gas pressure within a coke box, such as a Kress Indirect Dry Cooling (KIDC) coke box, as the hot coke is pushed into the box. As the coke enters the coke box, the coke displaces the ambient air in the box. As the ambient air in the coke box is displaced, without use of the pressure controller disclosed herein, it must pass back over the hot coke which increases the temperature and, thus, the volume of the now hot air up to four (4×) times. In order to eliminate this air flow back over the coke, means of balancing the air pressure in the box is proposed. It will also be possible, if desired, to produce a negative pressure in the box to pull any contaminants that might be generated solely by the act of pushing the coke into the box. The disclosed pressure controller can also capture these contaminants in a filter as described below.

[0016] As shown in FIGS. 1 and 2, an exemplary coke box 10 is shown that is suitable for use in accordance with the teachings of the present invention. The coke box 10 is rectangular in the shape of a parallelepiped and has a volume slightly greater than that of a coke charge C to be received in the box. The coke or charge C is typically pushed by a ram (not shown) from a coke oven (also not shown) into the coke box 10. This is done without changing the shape of the coke C. This is because the size and shape of the coke C is effectively the same but slightly smaller than that of the interior 12 of the box 10.

[0017] With such an arrangement, the breaking of the coke which would otherwise occur when the coke C is pushed and dropped into the conventional quench car is eliminated. One additional advantage of this arrangement is that the relatively large surface area of the thin, rectangular coke box 10 is well suited and conducive to efficient cooling, either through the surfaces of the box 10 or via an internally circulated inert gas. The coke box 10 can be made somewhat longer than the initial length of the coke charge C in order to accommodate any crumbling of the leading edge of the charge C as it is pushed into the interior 12 of the box 10.

[0018] It is desirable for the coke box 10 to be substantially air-tight to prevent ignition of the hot coke charge C. Further, the oven and the box 10 are substantially sealed relative to one another during the pushing operation. Therefore, during the pushing operation and thereafter, ignition of the hot coke C from the coke oven O is prevented. The air-tight coke box 10 also prevents substantially any particulate matter from escaping the box which would otherwise cause air pollution. In actuality, no particulate matter is generated since the coke stays in the cake form and is not disturbed.

[0019] With this general configuration, it is apparent that the solid coke charge C is displacing a relatively large volume of gases, such as the ambient air, within the interior 12 of the coke box 10 prior to being pushed into the box. The ambient air must somehow be discharged from the interior 12 of the coke box 10. The ambient air is also significantly heated by the hot coke C as it is being displaced and thus significantly expands. Because the interior 12 of the box 10 is substantially sealed, the air must pass back over the coke C as it is being pushed into the box. The air as it passes back over the hot coke will ignite some surface coke. However, the amount ignited will be only a fraction of that ignited during a conventional push into a quench car. As the hot coke C is pushed into the box 10 and fills the interior space 12, the gases such as the ambient air therein result in increased pressure. This pressure differential is controlled in accordance with the teachings of the present invention to eliminate the air flow back over the coke. FIGS. 3 and 4 illustrate an example of a pressure controller that can be utilized to prevent this air flow back.

[0020] As shown in FIGS. 3 and 4, the pressure controller has a spring loaded valve assembly 20 fixed to a coke box wall 22. The valve assembly 20 is mechanically opened by part of a suction fan assembly 24 as it is positioned at the valve 20. The valve assembly 20 has an inlet opening 26 in the wall 22 of the coke box 10. A valve assembly 20 also has a spring 28 that bears against a seal plate 30 which in turn, when in the closed position, bears against a seal 32 carried on a flange 34. The inlet opening 26 opens into a valve chamber 36 in which the seal plate 30 and spring 28 are installed. The flange 34 defines an outlet opening 38 in the opposite end of the chamber 36. In the closed position shown in FIG. 4, the seal plate 30 bears against the seal 32 closing off the outlet opening 38. The seal plate 30 is biased toward the seal 32 by the spring 28.

[0021] The pressure controller also has a barometer 40 or other type of pressure sensing device that communicates with the interior 12 of the coke box 10. The barometer 40 detects any pressure differential between the interior 12 of the coke box and the pressure external to the box, typically ambient air. The barometer can be provided with a control element such as a microprocessor 41, a compare circuit, or the like that senses or detects this pressure differential.

[0022] In the disclosed example, the barometer 40 has a transmitter 42 coupled with the microprocessor 41 that can transmit a signal in a desired form to the suction fan assembly 24, as described in greater detail below. The suction fan assembly 24 likewise has a receiver 44 with an antenna 65 coupled to a fan controller 26 that can communicate with the transmitter 42. The receiver 44 and antenna 65 receive a pressure differential signal from the transmitter 42 of the barometer 40 to control operation of the suction fan assembly 24. A controller 46 controls operation of the suction fan assembly 24 according to signals from the barometer 40. In one preferred example, the transmitter 42 and receiver 44 are radio frequency (RF) components that transmit and receive wireless signals.

[0023] In this example, the suction fan assembly 24 has a discharge outlet conduit 50. Air, other gases, and particulate matter are passed from the interior 12 of the coke box 10 through openings in the valve chamber 36 and the opening 38 into the conduit 50. If desired, the discharge conduit 50 can direct air or other gases downstream to an appropriate filter system 61 to filter out particulate matter and other contaminants. The fan assembly 24 can be located downstream of the filter system 61, if appropriate for a given system.

[0024] The disclosed suction fan assembly 24 has a fan motor 52 that is controlled by the controller 46. The fan motor 52 operates to drive a fan 54 of the suction fan assembly 24. The speed of the fan 54 and motor 52 can be controlled according to the barometer control signal 69 to balance pressure within the coke box 10 to prevent ambient air in the box from passing back over the hot coke back into the oven. If desired, the fan assembly 24 can be run to generate a negative pressure within the box 10 to remove particulate matter through the filter system 61 and prevent back flow to the oven.

[0025] In the disclosed example, the suction fan assembly 24 includes a fan housing 56 from which the discharge conduit 50 extends. The fan housing 56 also defines an air inlet 58 at one end as shown in FIG. 4. A flange 60 surrounds the inlet 58. The air inlet 58 and flange 60 can support or retain a valve opening surface 62 that permits air to flow by the device and yet will open the valve assembly 20. The surface 62 bears against a tapered surface 64 moving the seal plate to an open position as the fan assembly 24 moves into position permitting air to pass freely into the fan housing 56 through the inlet opening 58. To accommodate easy positioning of the fan assembly 24 to the valve assembly 20, a tapered surface 57 of the flange 60 contacts a tapered surface 35 of the flange 34 as the valve assembly moves into position. In addition, the tapered surface 57 assists in forcing the tapered surface 64 away from the seal 32 and flange 34 to thus open the seal plate 30. The seal plate is held in the open position by the valve opening surface 62 and tapered surface 64 as mentioned above.

[0026] The pressure controller as illustrated in FIGS. 3 and 4 can eliminate back pressure developed within the coke box 10 as the hot coke C enters the box. This back flow is also prevented from flowing back into the oven (not shown) which is sealed to the interior 12 of the coke box. This eliminates any possibility of transporting particulate matter back over the hot coke C in the box interior 12 and also into the coke oven. The fan 54 is operated to equalize pressure within the coke box 10 eliminating this back flow. By balancing the pressure, no particulate or volatile organic compounds (VOC) will be generated, or if generated, will be released to the atmosphere through the discharge conduit 50 and an appropriate filter system, if present.

[0027] It is typical to provide a plurality of coke boxes 10 for any given operation. Each coke box will have a rear outlet opening 38 in its own valve chamber 36. The fan housings 56 can be provided on the coke box carrier from which the fan or fans will receive operating power. The coke box carrier can either be provided with a single fan positioned remote to each individual coke box 10, or can be provided, as illustrated, with separate discrete fan assemblies 24, one for each coke box 10. Power to drive the fan and control system can be transmitted through slip bars that are coupled when the valves and fans engage. Where only a single fan is utilized it will be permanently attached to the carrier to connect to each box 10 as the coke charge push is applied. The radio transmitter 42 can provide the signal 69 through an antenna 66 to the antenna 65 to the fan controller 46. When transmitting the signal 69 by radio, the pressure sensor 39 and transmitter 41 will be powered by batteries. This signal can also be transmitted through wires 63 and 64 and slip rings 68. In this manner, a single fan can control varied air flows or air suctions individually to a plurality of coke boxes. Alternatively, if each coke box is provided with its own fan drive, the radio transmitter can be eliminated and a simple electrical connection to each box can be provided. The fan assembly and various electronic components can be powered by a power source on the KIDC carrier.

[0028] If necessary or desired, a discharge flow from the suction fan assembly 24 can be directed to an appropriate filter system. This may be necessary where a negative pressure is generated within the coke box 10, that might otherwise pull some minute particulate or VOC from the box.

[0029] Although a certain pressure controller and method has been disclosed and described herein in accordance with the teachings of the present invention, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention falling within the scope of the appended claims, either literally or under the doctrine of equivalents.

Claims

1. A pressure controller for a coke box, the pressure controller comprising: a fan assembly; a valve assembly selectively coupling the fan assembly to the coke box; a barometer for sensing a pressure in the coke box; and a control element for controlling a speed of the fan assembly to maintain a pressure in the coke box below a desired pressure level.

2. A pressure controller according to claim 1, wherein the control element transmits a signal from the barometer that is determined by comparing the pressure in the coke box to the desired pressure level.

3. A pressure controller according to claim 1, wherein the control element has a microprocessor electronically coupled with the barometer and has a transmitter for sending a signal used to control the speed of the fan assembly.

4. A pressure controller according to claim 3, wherein the signal is a radio frequency signal sent by the transmitter.

5. A pressure controller according to claim 3, wherein the fan assembly has a receiver for receiving the signal from the transmitter.

6. A pressure controller according to claim 1, wherein the valve assembly comprises: a valve chamber in communication with the coke box; a seal plate housed within the valve chamber; a spring arranged to bias the seal plate to a closed position preventing a change of pressure from the coke box through the valve assembly; and wherein the seal plate can be moved to an open position whereby the fan assembly can be operated to affect a pressure change in the coke box through the valve assembly.

7. A pressure controller according to claim 6, wherein the fan assembly has a valve opening surface adapted to move the seal plate to the open position when the fan assembly and the valve assembly are mated to one another.

8. A pressure controller according to claim 1, wherein the valve assembly is movable between an open position and a closed position by a portion of the fan assembly when the valve assembly and the fan assembly are coupled to one another.

9. A pressure controller according to claim 1, wherein the fan assembly has a fan housing, a fan in the fan housing, a fan motor, and a discharge conduit, wherein the motor drives the fan within the housing providing communication between the discharge conduit and the valve assembly through the fan housing.

10. A pressure controller according to claim 1, wherein the fan assembly can be controlled to generate a negative pressure in the coke box to capture any contaminates generated when a coke charge is pushed into the coke box.

11. A pressure controlled coke box comprising: a coke box having an interior; a fan assembly; a valve assembly selectively coupling the fan assembly with the coke box interior; a barometer for sensing a pressure in the coke box; and a control element for controlling a speed of the fan assembly to maintain the pressure in the coke box below a desired level.

12. A pressure controlled coke box according to claim 11, wherein the control element transmits a signal from the barometer, the signal determined by comparing the pressure in the coke box to the desired level.

13. A pressure controlled coke box according to claim 11, wherein the control element has a microprocessor electronically coupled with the barometer and has a transmitter for sending a signal used to control the speed of the fan assembly.

14. A pressure controlled coke box according to claim 13, wherein the signal is a radio frequency signal sent by the transmitter.

15. A pressure controlled coke box according to claim 11, wherein the valve assembly has a seal plate housed within a valve chamber and a spring arranged to bias the seal plate to a closed position preventing a change of pressure from the coke box through the valve assembly, and wherein the fan assembly has a valve opening device adapted to move the seal plate to an open position when the fan assembly and the valve assembly are coupled to one another permitting a pressure change in the coke box through the valve assembly.

16. A method of preventing pressure build up in a coke box and gas flow back into a coke oven when pushing a coke charge into an interior of the coke box, the method comprising the steps of: providing a valve assembly on a wall of the coke box selectively communicating with the coke box interior; selectively coupling a fan assembly with the valve assembly for selective communication with the coke box interior; mounting a barometer for sensing a pressure within the coke box interior; and controlling a speed of the fan assembly to maintain the pressure within the coke box interior below a desired level.

17. A method according to claim 16, wherein the fan assembly is provided on a coke box carrier, the step of selectively coupling occurs when the coke box is properly positioned relative to the carrier, and the step of selectively coupling further includes automatically moving a portion of the valve assembly from a closed position to an open position by contact with a portion of the fan assembly upon coupling the fan assembly with the valve assembly.

18. A method according to claim 16, wherein the step of controlling further comprises the steps of: comparing the pressure in the coke box interior with the desired pressure level at a microprocessor; transmitting a radio frequency signal from a transmitter to a receiver as a function of the comparison; and performing the step of controlling as a function of the comparison.

19. A method according to claim 16, wherein the fan assembly moves gas and particulate matter in the gas from the coke box and through a filter medium before passing the gas to atmosphere.

20. A method according to claim 19, wherein the fan assembly is positioned downstream of the filter medium.