Title of Invention

AN ADVANCE RAPPER OPERATING PROCESS FOR ELECTROSTATIC PRECIPITATION .

Abstract

An advanced rapper operating method for electrostatic precipitation (ESP) comprising o a rapper controller (7) which switches ON or OFF a rapper motor (12) through an output card (9), the ON or OFF status of motor (12) being conveyed to controller (7) by input card (10), the said rapper controller being connected to central computer of ESP (8) which collects information on parameters of interest (11) which comprises ESP-field position with respect to gas flow direction, healthiness of ESP field and dust load into ESP and communicates to said rapper controller continuously, and communicates to nsaid rapper controller continuously, the said rapper controller comprising of microprocessor (1) connected to a plurality of memories (3,4,5) through data control bus (B) and also to communication interface (2) characterized in that the time period of the rapper motor (12) is continuously adjusted, depending upon the changes in the said parameters of interest, automatically without any human intervention.

Full Text

TITLE: AN ADVANCED RAPPER OPERATING METHOD FOR ELECTROSTATIC PRECIPITATOR. FIELD OF INVENTION: The invention relates to operation of rapper drive motors deployed in electrostatic precipitator* used for air pollution control. BACKGROUND AND PRIOR ART: Electrostatic precipitation is one of the most effective ways to control air pollution generated by industrial emissions. This technique, which has proven highly effective in controlling air pullution, has been used fop the removal of undesirable particulate matter from a gas stream by electrostatic precipitation. Electrostatic precipitator (hereafter referred to as ESP) is an air pollution control device designed to electrically charge and collect particulates generated from industrial processes such as those occurring in power plants, cement plants, pulp and paper mills and utilities etc. The electrically charged particles are attracted towards electrode plates, viz., discharge electrode and collection plate. ESP is divided into a plurality of fields depending on the dust load. A field is a set of a discharge electrode and collection plate. A field is considered healthy as long as it is charged with sufficient voltage and current between its discharge and collection plate. During continuous operation of an electrostatic precipitator, the dust from collector plates electrodes must be periodically removed for further conveying of the collected dust. The dust removal mechanism typically consists of a mechanical rapper. Rappers are electro-mechanical devices that are used to mechanically dislodge collected particulate/materials within an electrostatic precipitator or dust collector. In general, a rapper consists of a rapper motor connected to hammer mechanism that mechanically strikes shock pad of respective electrode to which it is connected. Striking the field electrode at shock pad with the hammer transmits mechanical forces to dislodge collected materials. This type of rapping system is called tumbling-hammer type rapper. Once the particulate is dislodged from the plates, it falls into collection hoppers at the bottom of the precipitator. An electronic rapper controller, which operates rapping motor, determines the sequence, intensity, and duration of rapping. In the prior art, conventional rapper controllers for a tumbling hammer type rapping system are known, which control rapper motors by switching them ON or OFF periodically, so as to allow ash build-up on plates during OFF time and ash removal during ON time. These periods are dictated by ESP's operating parameters viz., rapper motor's location with respect to gas flow, overall dust load into electrostatic precipitator and other user defined options. ON and OFF time* are critically set to avoid excessive rapping or under rapping, both of which are detrimental to ESP performance. Excessive rapping will lead to more re-entrainment and under rapping will cause more sparking in ESP, both resulting in poor performance-of ESP. It is also known in the prior art that electronic controllers control rapping motors, which drive hammers to remove ash/dust collected on plates. These electronic controllers can be of analog or digital type. Irrespective of p the type of the controller, ON time and OFF time of rapping motor remain basic parameters for controlling. ON/OFF time i.e. time period, of a field will vary depending on the particular field's location with respect to gas flow direction. If the field is nearer to ESP entry, then the frequency of rapping will be more, as the dust collection in that field will be more. The frequency of rapping will reduce towards the end of ESP. The frequency of rapper operation is determined by three operating parameters viz., Start-time, Run-time and Repeat-time. Start-time determines the starting time of rapping motor, Run-time determines how long a rapper shall run and Repeat-time determines the time gap between two Start-times. These timings are generally known as periods of rapping. In the prior art, mechanisms exist to set the periods directly in the rapper controller and/or from a master controller. These timings are calculated and set based on the dust load entering each field of the ESP along the gas flow direction and other user defined methods. Mechanisms also exist to change the rapper period which is proportional to the plant-operating load, as the dust load entering the ESP is proportional to the plant-operating load. But no mechanism presently exists to adjust the periods of rapping motors in an ESP automatically without human intervention depending on the ESP-field conditions. The subject invention seeks to overcome this drawback. OBJECTS OF THE INVENTION: The invention seeks to provide an improved method to monitor various parameters of the ESP viz., current position of all rappers with respect to gas flow, healthiness of the fields, and overall dust load into ESP. Another object of the invention is to minimise manual interference in the operation of the rapper motors of ESP, thereby reducing losses due to human error. Yet another object is to achieve automatic and continuous optimisation of rapper operation timings under varying operating conditions. DESCRIPTION OF THE INVENTION: The timings of a rapper should change if there is any change in the healthiness of any ESP-field immediately preceding its own ESP-field (i.e. to which it is attached). For example, if first ESP-field has failed, then second ESP-field will effectively become first ESP-field with respect to gas flow direction. pHealthiness of a field means that particularly field is powered and functioning as expected. Healthiness of a field is achieved when the particular ESP-field is charged with sufficient voltage and current between its discharge and collection plates.Further, the overall dust load into ESP is directly proportional to the plant-operating load. A plurality of such monitored parameters are to be communicated to respective rapper controller. The rapper controller shall then modify the period of operation of rapper motor automatically without any human intervention based on these monitored parameters. The rapper motor periods are pre-calculated based an ESP operating parameters., viz., position of the respective field with respect to gas flow, healthiness of the fields and overall dust load into ESP. These periods are stored in memory of microprocessor based rapper controller. The rapper controller communicates with centralized controller for ESP for periodic updates of ESP operating parameters. If there is any change in ESP-field healthiness status, rapper controller will read new periods for all rapper motors from its memory. This process is done without any human intervention. The invention will now be described in detail with reference to the accompanying drawings. Brief description of accompanying drawings : FIG. 1 is a block diagram illustrating the processor schematics of micro-processor based controller with pre-calculated rapper periods stored in memory unit. FIG. 2 is a flow diagram of rapper operating periods control logic. FIG. 3 is a block diagram illustrating the method according to the invention. This invention deals with an advanced rapper operating method, which specifically deals with operating rapping system of ESP for a power plant or process plant. By continuously monitoring the ESP operating parameters, the rapping time periods of a particular rapper are continuously adjusted so that the rapping system gives an optimum rapping. The parameters, which are monitored continuously, are the position of the particular ESP- field in which the rapper is connected, healthiness of the partucular ESP-field and overall dust load into ESP. On monitoring these parameters continuously, the electronic rapper controller can decide on whether any of the currently operating time periods are to bechanged or not. If the periods are to be adjusted based on the monitored parameters, the electronic rapper controller will retrieve a suitable time period set from its memory and update its current operatimg time period. The time periods are pre-calculated based on ESP parameters, viz. position of the respective field with respect to gas flow, healthiness of the field and overall dust load into ESP and stored in memory. This automatic monitoring of ESP parameters and updation of time periods is done without any human intervention. In the block diagram shown in Fig. 1, micro-processor (1) is connected to a plurality of memory units, which are integrated circuits, through data and control bus. Memory (3) is used to store the programme of rapper controller. Memory (3) stores variables of program during execution. The micro-processor is also connected to the communication interface (2), which acts as an interface between rapper controller and central computer of ESP. The monitored data viz., field position with respect to gas flow, ESP-field healthiness and overall dust load into ESP are communicated to rapper controller through this communication interface. On receipt of such parameters, the rapper controller modifies the current time periods with the new one from its memory automatically so that the rapping system functions optimally and effectively. The logic of retrieving new time periods is explained in figure 2. At startup, the rapper controller loads a default time period (16) into its memory as current time period. It also starts communication with the central computer for ESP through its communication interface (2). Using communication, the rapper controller receives parameter information viz., ESP—field position with respect to gas flow direction, healthiness of ESP- field and dust load into ESP, from central computer (17). Upon checking the parameters, rapper controller decides what action to take. It may either change the current time period or leave without any change (18). This process continues as long as the rapper controller is operating. Figure 3 shows how the overall system is arranged. The rapper controller (7) is connected to output card (9), which switches ON or OFF a rapper motor (12) through a connecting cable. The motor ON or OFF status is conveyed through a cable to rapper controller by input card (10). The rapper controller (7) is connected to central computer of ESP (8) for information on parameters of interest. The central computer of ESP (8) collects information on those parameters (11) and communicates them to rapper controller continuously. After receipt of the information, the rapper controller decides on changing the time period if required. The invention thus provides an advanced rapper operating method for electrostatic precipitators (ESP) comprising a rapper controller which switches ON or OFF a rapper motor through an output card, the ON or OFF status of motor being conveyed to controller by input card, the said rapper controller being connected to central computer of ESP which collects information on parameters of interest and communicates to said rapper controller continuously, the said rapper controller comprising of a microprocessor connected to a plurality of memories through data control bus and also to communication interface characterized in that the time period of the rapper motor is continuously adjusted depending upon the changes in the said parameters of interest automatically without any human intervention. WE CLAIM 1. An advanced rapper operating method for electrostatic precipitation (ESP) comprising o a rapper controller (7) which switches ON or OFF a rapper motor (12) through an output card (9), the ON or OFF status of motor (12) being conveyed to controller (7) by input card (10), the said rapper controller being connected to central computer of ESP (8) which collects information on parameters of interest (11) which comprises ESP-field position with respect to gas flow direction, healthiness of ESP field and dust load into ESP and communicates to said rapper controller continuously, and communicates to isaid rapper controller continuously, the said rapper controller comprising of micro-processor (1) connected to a plurality of memories (3,4,5) through data control bus (B) and also to communication interface (2) characterized in that the time period of the rapper motor (12) is continuously adjusted, depending upon the changes in the said parameters of interest, automatically without any human intervention. 2. An advanced rapper operating method as claimed in claim 1, wherein memory (3) stores the programme of the rapper controller (7), memory (4) stores the precalculated time periods with indexing, memory (5) stores the variables of programme during execution and the micro-processor (1) can retrieve any stored data during execution of the programme. 3. An advanced rapper operating method as claimed in Claim 1 and 2, wherein said memory comprises an integrated circuit (1C) to store desired data permanently. 4. An advanced rapper operating method as claimed in Claim 1, wherein the ESP is divided into a plurality of fields, each field comprising of a set of a discharge electrode and collection plate, the said method monitoring the healthiness of all the fields continuously and adjusting the rapping period according to the healthiness of one or several fields. 5. An advanced rapper operating method as claimed in Claims X and 2, wherein the said method retrieves the appropriate precalculated time period for the rapper central motor (12) from memory (4) depending upon the changes in the parameters of interest and replace load default time period (16) with the new time period so retrieved. 6. An advanced rapper operating method as claimed in claims 1 and 3, wherein the parameters of interest includes field position with respect to gas flow direction, healthiness of fields and dust load into ESP. 7. An advanced rapper operating method as claimed in claim 6, wherein healthiness of field is achieved when the particular ESP- field is charged with sufficient voltage and current between its discharge and collection plates. 8. An advances rapper operating method as claimed in claim 5, the pre-calculated time period is dependant on healthiness of fields which in-turn affects field position with respect to gas flow direction. ?. An advanced rapper operating method for electrostatic precipitator substantially as herein described and illustrated. Dated this 20th day of February, 2006. An advanced rapper operating method for electrostatic precipitation (ESP) comprising o a rapper controller (7) which switches ON or OFF a rapper motor (12) through an output card (9), the ON or OFF status of motor (12) being conveyed to controller (7) by input card (10), the said rapper controller being connected to central computer of ESP (8) which collects information on parameters of interest (11) which comprises ESP-field position with respect to gas flow direction, healthiness of ESP field and dust load into ESP and communicates to said rapper controller continuously, and communicates to nsaid rapper controller continuously, the said rapper controller comprising of microprocessor (1) connected to a plurality of memories (3,4,5) through data control bus (B) and also to communication interface (2) characterized in that the time period of the rapper motor (12) is continuously adjusted, depending upon the changes in the said parameters of interest, automatically without any human intervention.

Documents:

151-KOL-2006-FORM-27.pdf

151-kol-2006-granted-abstract.pdf

151-kol-2006-granted-claims.pdf

151-kol-2006-granted-correspondence.pdf

151-kol-2006-granted-description (complete).pdf

151-kol-2006-granted-drawings.pdf

151-kol-2006-granted-examination report.pdf

151-kol-2006-granted-form 1.pdf

151-kol-2006-granted-form 18.pdf

151-kol-2006-granted-form 2.pdf

151-kol-2006-granted-form 3.pdf

151-kol-2006-granted-gpa.pdf

151-kol-2006-granted-reply to examination report.pdf

151-kol-2006-granted-specification.pdf