Claims:WE CLAIM:
1. An automated system for constant pressured delivery of liquor to coke oven battery during charging operation comprising
a liquor delivery pump connected with one or more coke oven battery for delivering the liquor to the coke oven battery;
atleast one flow sensor for each of the coke oven battery to sense flow of the liquor to the coke oven battery and accordingly detect the charging operation in the coke oven battery;
a flow controller connected to the flow sensor and the liquor delivery pump for receiving signal from the flow sensor and driving the liquor delivery pump for delivery of the liquor to the coke oven battery at a desired pressure during the charging operation in the coke oven battery.

2. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in claim 1, wherein the liquor delivery pump is connected to the one or more coke oven battery through liquor transmissible communication network including individual liquor transferring line of each connected coke oven battery for delivering the liquor to any of the connected coke oven battery though said liquor transmissible communication network and the liquor transferring line of that connected coke oven battery.

3. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claim 1 or 2, wherein the flow sensor is disposed on the liquor transferring line for sensing flow rate of the liquor through the liquor transferring line.

4. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claims 1 to 3, wherein the liquor delivery pump continuously operate at lower speed for circulating the liquor in the liquor transmissible communication network,whereby the flow rate of the liquor circulating in the liquor transferring line remains low during normal operation of the coke oven battery which is sensed by the flow sensor.

5. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claims 1 to 4, wherein the flow sensor detects initiation and carrying out of the charging operation in the coke oven battery upon sensing the flow rate of the liquor circulating in the liquor transferring line crossing a threshold flow rate and accordingly signal the flow controller to drive the liquor delivery pump at higher speed through a variable frequency drive ensuring delivery of the liquor to the coke oven battery through the liquor transmissible communication network and the liquor transferring line at the desired pressure required for facilitating oven to oven gas transfer during the charging operation.

6. The automated system for constant pressured delivery of liquor to coke oven battery charging during operation as claimed in anyone of claims 1 to 5, wherein the liquor delivery pump preferably includes multi stage rotary pump configured to operate at the lower speed of 1500rpm during the normal operation and the higher speed of 2500rpm during the charging operation for delivering the liquor to the coke oven battery at the desired pressure of 30 bar for facilitating the oven to oven gas transfer during the charging operation.

7. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claims 1 to 5, wherein the flow sensor preferably includes orifice type flow sensor with differential pressure transmitter with operating range of 0-50m3/hr for comparing the flow rate of the liquor in the liquor transferring line with respect to the threshold flow rate of7m3/hr and detecting the charging operation as soon as it senses the flow rate of above 7m3/hr in the liquor transferring line.

8. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claims 1 to 7, wherein the flow controller includes Siemens S7 414H PLC for receiving signal from the flow sensors corresponding to the connected coke oven batteries and drive the pump at higher speed upon detecting the charging operation in any of the connected coke oven batteries.

9. The automated system for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claims 1 to 8, wherein the liquor preferably includes high pressure liquid ammonia.

10. A method for constant pressured delivery of liquor to coke oven battery during charging operation comprising
involving a liquor delivery pump;
connecting said liquor delivery pump to one or more coke oven battery through liquor transmissible communication network including individual liquor transferring line of each connected coke oven battery for delivering the liquor to the coke oven battery;
involving atleast one flow sensor for each of the coke oven battery and disposing the flow sensor on the liquor transferring line to sense flow of the liquor to the coke oven battery and detect initiation and carrying out of the charging operation in the coke oven battery upon sensing the flow rate of the liquor in the liquor transferring line crossing a threshold flow rate;
involving flow controller and connecting the same with the flow sensors and the liquor delivery pump for receiving signal from the flow sensors and driving the liquor delivery pump for delivery of the liquor to the coke oven battery at a desired pressure during the charging operation in any of the coke oven battery detected by the corresponding the flow sensor.

11. The method for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in claim 10, wherein liquor delivery pump continuously operate at lower speed for circulating the liquor in the liquor transmissible communication network, whereby the flow rate of the liquor circulating in the liquor transferring line remains below the threshold flow rate during normal operation of the coke oven battery which is sensed by the flow sensor.

12. The method for constant pressured delivery of liquor to coke oven battery during charging operation as claimed in anyone of claim 10 or 11, wherein the flow sensor signalling the flow controller on the initiation and carrying out of the charging operation in the coke oven battery upon sensing the flow rate of the liquor circulating in the liquor transferring line crossing the threshold flow rate to drive theliquor delivery pump at higher speed through a variable frequency drive ensuring delivery of the liquor to the coke oven battery through the liquor transmissible communication network and the liquor transferring line at the desired pressure required for facilitating oven to oven gas transfer during the charging operation.

Dated this the 9th day of January, 2018
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)
IN/PA-199

, Description:FIELD OF THE INVENTION:
The present invention relatesto optimizing delivery of ammonia liquorto coke oven batterydepending on operational status of the coke oven battery. More specifically, the present invention is directed to develop an automated system and a method for optimized deliveryof the ammonia liquorto coke oven battery at a desired pressure required for facilitating oven to oven gas transfer during the charging operation.

BACKGROUND OF THE INVENTION:
A coke oven battery is basically collection of ovens that are built in a row with common walls between neighbouring ovens. In a steel processing plant the coke oven battery is used for producing hard coke for use in blast furnace by carbonization of selected coal blend.
In the coke oven battery, raw coke oven gas emitted during carbonization of coal in carbonization chamber of the ovens, is collected into gas collection and cleaning system of the Coke Oven Battery via gas collection main. The raw coke oven gas, emitted during carbonization of coal in a Coking Unit, is collected into gas collection and cleaning system of Coke Oven Batteries via the gas collection main. The gas collection system, where gas is sucked by gas exhausters, operates at a constant pressure.
Now during charging of the coke oven battery, due to increased emission of gases (when raw coal comes in contact with hot walls of the carbonization chamber which is isolated from the gas collecting system, there is no suction available from it's own ascension pipe) and availability of open space on top of the oven where the coal cake being charged, a lot of raw coke oven gas escapes into open atmospheres, creating considerable emission and pollution.
To circumvent the escape of the raw coke oven gas during the charging operation,carbonization chamber of the ovenbeing charged is connected with chambers of the adjacent ovenswhich are still connected to the gas collecting system. Further highpressure liquor Ammonia is sprayed in goose neck area of gas collecting ascension pipe which connects the adjacent carbonization chambers of the coke oven battery to the gas collecting mains such as to create additional suction due to venturi effect and minimizes the escape of the gas into open atmosphere during charging.
The accompanying figure 1 shows a state of art system for supplying/deliveringliquor Ammoniato multiple coke over batteries. As shown in the referred figure 1, theliquor Ammonia supply lines of all thecoke over batteries are connected to liquor Ammonia delivery line of the high pressure liquor (HPLA) Ammonia pump.
The control philosophy of the state of art liquor Ammonia supplying/delivering systemis to keep the liquid pressurized in the system and whenever there is drop in pressure due to demand of high pressure liquor ammonia in the carbonization chamber of any of the connected coke oven chambers undergoing charging, subsequent pressure drop is sensed by a pressure transmitter disposed on the liquor Ammonia delivery line and signal given to PLC based pressure controller which further connected with a variable frequency drive (VFD). The VFD controller is PID looped with the pressure transmitter such that rotation speed of the HPLA pump is increased/decreased to keep the liquid pressurized at 30 bar.
Now, in the existing liquor Ammonia supplying/delivering system, since the pressure transmitter is installed right at the delivery of the pump and distance between pump and carbonization chamber being greater than 300 mtrs, it is often fail to correctly assert the pressure dropdue to concluding of the charging operation in the coke oven battery by measuring the pressure in the liquor Ammonia delivery line resulting operating the HPLA plump at higher speed keeping the liquid circulating in closed loop and defeating the purpose of VFD namely saving on electric power when high pressure liquor is not in demand.
In a typical battery of coke oven, the charging cycle lasts 2 to 3 minutes and then there is a waiting of 15 minutes till the next charging cycle commences. The High Pressure Liquor Ammonia spraying is required only during charging cycle, which lasts only 2 to 3 minutes in the entire cycle of coal pushing, coal cake charging, coal cake preparation and coke pushing which lasts 15 to 18 minutes.
Thus there has been a need for developing a new system and method for optimizing the operation of the pump to deliverthe liquorammonia into the coke oven battery at the desired high pressure required for facilitating the oven to oven gas transfer only during the charging operation.

OBJECT OF THE INVENTION:
The basic object of the present invention is to develop a system for deliveringliquorammonia to coke oven battery which would be adapted to automatically deliverthe liquor to one or more coke oven battery at a desired pressure required for facilitating oven to oven gas transfer during charging operation.

Another object of the present inventionis to develop a systemfor deliveringliquorammonia to coke oven battery which would be adapted torapidly detect initiation and/or concluding of the charging operation in the coke oven battery accordingly operate theliquor delivery pump for deliveringthe liquor to one or more coke oven battery at a desired pressure required for facilitating oven to oven gas transfer during charging operation.

Another object of the present inventionis to develop a systemfor deliveringliquorto coke oven battery which would be adapted to optimize operation time of the liquor delivery pump and minimize the related energy consumption.

Yet another object of the present invention is to develop a method for deliveringliquorto coke oven battery which would be adapted to automatically deliverthe liquor to one or more coke oven battery at a desired pressure required for facilitating oven to oven gas transfer during charging operation.

SUMMARY OF THE INVENTION:

Thus according to the basic aspect of the present invention there is provided an automated system for constant pressured delivery of liquor to coke oven batteryduring charging operation comprising
aliquor delivery pump connected with one or more coke oven battery for delivering the liquor to thecoke oven battery;
atleast one flow sensor for each of the coke oven battery tosenseflow of the liquor to the coke oven battery and accordingly detect the charging operation in the coke oven battery;
aflow controller connected to the flow sensor and the liquor delivery pump for receiving signal from the flow sensor and driving the liquor delivery pump for delivery of the liquor to the coke oven battery at a desired pressure during the charging operation in thecoke oven battery.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the liquor delivery pump is connected to the one or more coke oven battery through liquor transmissible communication network including individual liquor transferring line of each connected coke oven battery for delivering the liquor to any of the connected coke oven battery though said liquor transmissible communication network and the liquor transferring line of that connected coke oven battery.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the flow sensor is disposed on the liquor transferring line for sensing flow rate of the liquor through the liquor transferring line.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, theliquor delivery pump continuously operate at lower speed for circulating the liquor in the liquor transmissible communication network, whereby the flow rate of the liquor circulating in the liquor transferring line remains low during normal operation of thecoke oven battery which is sensed by the flow sensor.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the flow sensordetects initiation and carrying out of the charging operation in the coke oven battery upon sensing theflow rate of the liquor circulating in the liquor transferring line crossing a threshold flow rate and accordingly signal the flow controller to drive theliquor delivery pump at higher speed through a variable frequency drive ensuring delivery of the liquor to the coke oven battery through theliquor transmissible communication network and theliquor transferring line at the desired pressure required for facilitating oven to oven gas transfer during the charging operation.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the liquor delivery pump preferably includes multi stage rotary pump configured to operate at the lower speed of 1500rpm during the normal operation and thehigher speed of 2500rpm during the charging operation for delivering the liquor to the coke oven batteryat the desired pressure of 30 bar for facilitating the oven to oven gas transfer during the charging operation.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the flow sensor preferably includes orifice type flow sensor with differential pressure transmitter with operating range of 0-50m3/hr for comparing the flow rate of the liquor in the liquor transferring line with respect to the threshold flow rate of 7m3/hr and detecting the charging operation as soon as it senses the flow rate of above 7m3/hr in the liquor transferring line.

In an embodiment of the present automated system for constant pressured delivery of liquor to coke oven battery during charging operation, the flow controller includes Siemens S7 414H PLC for receiving signal from the flow sensors corresponding to the connected coke oven batteries and drive the pump at higher speed via variable frequency drive (VFD) upon detecting the charging operation in any of the connected coke oven batteries.

In an embodiment of the present automated system for constant pressured delivery of liquor tocoke oven batteryduring charging operation, the liquor preferably includes high pressure liquid ammonia.

According to another aspect in the present invention, there is provided a method for constant pressured delivery of liquor to coke oven battery during charging operation comprising
involving a liquor delivery pump;
connecting said liquor delivery pump to one or more coke oven batterythrough liquor transmissible communication network including individual liquor transferring line of each connected coke oven battery for delivering the liquor to thecoke oven battery;
involving atleast one flow sensor for each of the coke oven battery and disposing the flow sensoron the liquor transferring line tosenseflow of the liquor to the coke oven battery and detect initiation and carrying out of the charging operation in the coke oven battery upon sensing theflow rate of the liquor in the liquor transferring line crossing a threshold flow rate;
involvingflow controller and connecting the same with the flow sensors and theliquor delivery pump for receiving signal from the flow sensors and driving the liquor delivery pump for delivery of the liquor to the coke oven battery at a desired pressure during the charging operation in any of thecoke oven battery detected by the corresponding the flow sensor.

In above method for constant pressured delivery of liquor to coke oven battery during charging operation, theliquor delivery pumpcontinuously operate at lower speed for circulating the liquor in the liquor transmissible communication network, whereby the flow rate of the liquor circulating in the liquor transferring line remains below the threshold flow rate during normal operation of thecoke oven battery which is sensed by the flow sensor.

In above method for constant pressured delivery of liquor to coke oven battery during charging operation, the flow sensorsignalling the flow controller on the initiation and carrying out of the charging operation in the coke oven battery upon sensing theflow rate of the liquor circulating in the liquor transferring line crossing the threshold flow rate to drive theliquor delivery pump at higher speed through a variable frequency drive ensuring delivery of the liquor to the coke oven battery through theliquor transmissible communication network and theliquor transferring line at the desired pressure required for facilitating oven to oven gas transfer during the charging operation.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1: shows schematic representation of a preferred embodiment of the state of art system for supplying/deliveringliquor Ammonia to multiple coke over batteries.
Figure 2: shows schematic representation of a preferred embodiment ofautomated system for constant pressured delivery of liquor to coke oven batteryduring charging operation in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
As stated hereinbefore, the present discloses an automated system and method for constant pressured delivery of liquor ammonia to coke oven batteryduring only charging operationfor facilitating the oven to oven gas transfer by selectively optimizing the liquordelivery pumping operation.The present system and method is particularly configured to operate the liquordelivery pumponly during charging operation to facilitate transfer of the raw coke oven gasfrom the oven being charged to the adjacentoven of thecoke oven battery. In the present invention, the liquordelivery pump is operated based on the flow rate of the liquor supplied to thecoke oven battery. Basically,valves to Gas Cleaning plant (GCM) connecting the ovens are opened during charging operation and the flow of liquor to GCM increases during this valve opening resulting increase in flow rate of the liquor in lines connecting the liquordelivery pump and the coke oven batteryindirectly indicating start of the charging process in the oven of the connected coke oven battery.
Reference is now invited from the accompanying figure 2 which shows a preferred embodiment of the present automated system for constant pressured delivery of liquor to coke oven batteryduring charging operation in accordance with a preferred embodiment of the present invention.The present automated system (1) for constant pressured delivery of liquor to coke oven batteryduring charging operation basically includesa liquor delivery pump (3) for delivering liquor to one or more coke oven batteries (A1, A2, B1, B2, ...), one or more flow sensor (2a, 2b,.., ) for sensing rate flow of theliquor to the coke oven batteries and aflow controller (5)with cooperative variable frequency drive (6) for controlling pumping speed of the liquor delivery pump (3) depending on sensory signal received from the flow sensor (2a, 2b,..,).
The embodiment of the present system (1) as shown in the referred figure 2, the liquor delivery pump (3) is connected to four coke oven batteries (A1, A2, B1, B2)through a liquor transmissible communication networkfor delivering the liquor to the connected coke oven battery. The number of coke oven batteriesthat can be connected with the liquor delivery pump (3) through the liquor transmissible communication network may be more than four or less than four. The liquor transmissible communication network preferably includes a common liquor delivery line (7) coming out from theliquor delivery pump (3) and individualliquor transferring lines (8a, 8b, 8c, 8d) corresponding to each coke oven battery (A1, A2, B1, B2) connected to said common liquor delivery line (7).
As shown in the referred figure 2, each of the liquor transferring lines (8a, 8b, 8c, 8d) includes atleast one of the flow sensors(2a, 2b, 2c, 2d)which provided tosense flow rate of the liquor through the liquor transferring line andaccordingly detect the charging operation in the coke oven battery corresponding to the liquor transferring line in which the liquorflow rate is being sensed.
All of the flow sensors (2a, 2b, 2c, 2d) are disposed in operative communication with the flow controller (4). Theflow controller (4) comprises PLC based means configured to receive the sensory signal from theflow sensors (2a, 2b, 2c, 2d)indicating the charging condition including the initiation and concluding in any of the connected coke oven battery (A1, A2, B1, B2)and control pumping speed of theliquor delivery pump (3) through the variable frequency drive (5) for delivery of the liquorat a desired pressure to the coke oven battery,on which the charging operationis detected by the corresponding flow sensor, through the liquor transmissible communication network and the liquor transferring line of that connected coke oven battery. The desired pressure for delivering the liquor to the coke oven batterywhich is undergoing through a charging operation should be enough for facilitating oven to oven gas transfer during the charging operation.
In a preferred embodiment of the present invention, the flow sensor preferably includes orifice type flow sensor with differential pressure transmitter with operating range of 0-50m3/hr and particularly configured to compare the flow rate of the liquor in the liquor transferring line with respect to a threshold flow rate and detecting the charging operation as soon as it senses the flow rate of above the threshold flow rate in the liquor transferring line. The threshold flow rate may vary depending on the system and the coke oven configuration.
In the present system, theliquor delivery pumpis configured to operate in lower speed during normal condition of the connected coke oven battery to circulate the liquorin the liquor transmissible communication network of the system. During normal condition, the valves to the GCM connecting the ovens are remain closed, thusthe flow rate of the liquor circulating in the liquor transferring lines remain low during the normal operation of thecoke oven battery which is sensed by the flow sensor. Now, upon initiation of the charging condition in any one of the connected coke oven battery, the valves to the gas cleaning plant (GCM) connecting the ovens are opened and the flow of liquor to GCM increases during this valve opening resulting increase in flow rate of the liquor in the liquor transferring line of the connected coke oven battery undergoing the charging operation. The flow sensorattached with the liquor transferring line detects such initiation and carrying out of the charging operation in the coke oven batteryby sensing theflow rate of the liquor circulating in the liquor transferring line upon crossing the threshold value and accordingly send signal to the PLC based flow controller.
The flow controller includes Siemens S7 414H PLC for receiving the signal from the flow sensors corresponding to the connected coke oven batteries and drive the pump at higher speed through the variable frequency drive upon detecting the charging operation in any of the connected coke oven batteries to ensure delivery of the liquor to that coke oven battery through the liquor transmissible communication network and the liquor transferring line at the desired pressure required for facilitating oven to oven gas transfer during the charging operation.
The system of the present invention has been successfully tested in controlling the delivery of the liquor ammonia of two coke oven batteries of 55 ovens each and reducing liquor delivery pump energy consumptions. Each coke oven battery is further divided into two section consisting of 27 and 28 ovens each. Each section has it's own gas collecting mains connecting the section to gas collecting system of the entire coke ovens. The liquor ammonia and high pressure liquor headers are also segmented as gas collecting mains. This is done to facilitate isolation of one section and undertaking maintenance activity.
Each individual sections has orifice type flow meters installed in their own liquor transferring line for measuring the flow of liquor ammonia into individual sections. Since only one carbonization chamber undergoes pushing / charging cycle at one time, the signal of flow increase is generated only from one section and the liquor ammonia pump motor is signaled to operate at higher state of delivery (i.e 2500 rpm) of pressurized liquor ammonia when the flow rate cross the threshold flow rate value of 7m3/hrto meet the increasing demand. When the valves in the carbonization chambers are closed post charging/pushing operation, the flow transmitter signals decrease in flow and the pump is brought down the lower normal state of delivery (i,e 1500 rpm). This way the pump is operated at two discrete states of delivery viz. steady state at RPM 1500 with pressure at 12 bar and exalted state at RPM 2500 with pressure at 30 bar which significantly reduce pump operation time in the higher speed/exalted state.Due to much reduced operation time in the exalted state as compared to steady state, there is considerable savings in electrical energy.