EP0537307A1 - Verfahren zum Warmhalten von Turbinen - Google Patents

Verfahren zum Warmhalten von Turbinen Download PDF

Info

Publication number
EP0537307A1
EP0537307A1 EP19920907519 EP92907519A EP0537307A1 EP 0537307 A1 EP0537307 A1 EP 0537307A1 EP 19920907519 EP19920907519 EP 19920907519 EP 92907519 A EP92907519 A EP 92907519A EP 0537307 A1 EP0537307 A1 EP 0537307A1
Authority
EP
European Patent Office
Prior art keywords
turbine
heating
temperature
blankets
electric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19920907519
Other languages
English (en)
French (fr)
Inventor
Cruz Antonio Lara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SEVILLANA DE ELECTRICIDAD SA
Original Assignee
SEVILLANA DE ELECTRICIDAD SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SEVILLANA DE ELECTRICIDAD SA filed Critical SEVILLANA DE ELECTRICIDAD SA
Publication of EP0537307A1 publication Critical patent/EP0537307A1/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/08—Cooling; Heating; Heat-insulation
    • F01D25/10—Heating, e.g. warming-up before starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/02—Arrangement of sensing elements
    • F01D17/08—Arrangement of sensing elements responsive to condition of working-fluid, e.g. pressure
    • F01D17/085—Arrangement of sensing elements responsive to condition of working-fluid, e.g. pressure to temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D19/00—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith
    • F01D19/02—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith dependent on temperature of component parts, e.g. of turbine-casing

Definitions

  • the present invention is related to a system for maintaining warm high power turbines, essentially steam turbines.
  • a system which by means of electric heating blankets attached to the exterior surface of a turbine and controlled by an automatic and computerized mechanism capable of predicting the possible behaviours of the machine when said machine undergoes changes of temperature, offers the possibility of maintaining a determined thermal level in the rotor, so that the start-up time in cold may be reduced, saving thereby fuel and electrical energy, and also reducing or even eliminating cycles of warming up-cooling off, which are normal in the operation of the machine thus making longer the life of the same.
  • the Thermal Groups not originally designed for cold start-ups, consume the time and the fuel during start-up in two clearly different phases.
  • the necessary energy is supplied to the boiler in order to increase its energetic level based on heating a large mass up to a determined value, the efficiency of which is certainly improvable, although it can be considered as acceptable.
  • the turbine phase which may be called “turbine phase” the turbine of a relatively small mass is heated, with a small quantity of value (approximately 3% of the nominal) proceeding from the boiler, attending to the thermal gradient, especially to that of rotor, and the differential expansion between fixed and movable parts.
  • Such power available as reserve in Switching Rooms, may be needed either by demand peaks, or by problems in interconnection lines or by unavailability of other groups; and in the majority of the cases when needed, it is required as fast and as safe as possible.
  • the objective of the invention is to implant a system for maintaining warm the high and medium pressure bodies of steam turbines, thus avoiding heating by cyclic steam, and by means of an arrangement of electric resistances adequately adapted.
  • a turbine of this type has been tested and installed in the United States, although only for low power turbines, which can not satisfy the demands of higher power turbines.
  • the extrapolation from low power to high power applications, which is the object of the present invention is the result of an extensive program of research and investigations for the development of the new system, intensively performed on the basis of an exhaustive thermoelastic analysis which has served as a basis so that the new system has the sufficient data on the nature and functioning of the machine and thus is capable of foreseeing or predicting the possible behaviours of the same.
  • the system has, as well, a computer program specially elaborated in order to satisfy the practical demands of the turbine.
  • the general rules of operation of a turbine indicate that in order for it to come to an adequate state of start-up, the rotor has to reach certain level of temperature.
  • Said temperature is a set point in such a manner that in lower temperatures the machine is considered to be cold, and before being coupled to the network it is necessary to warm up and homogenize temperatures by running steam during the time and by the velocity that are adequate for the case.
  • the machine is considered to be warm, and it does not need any delay time; (the only requirement in this case is that the temperature of the principal steam admission valves are higher than or equal to that of the steam saturation in the admission pressure).
  • the hereby proposed system for maintaining turbines warm is ment to satisfy such requirements maintaining the temperature of the machine on the adequate level so that said machine is continuously kept in the appropriate condition for a rapid start.
  • the system consists of three different parts:
  • the DAS consists of an automatic and computerized system , specifically useful for such an application, and provides flexibility and simplicity in handling the same.
  • the equipment for acquisition of data and control comprises essentially of a computer capable of running the relevant program either for the acquisition of data or for the control having its peripheral units such as printer, and plotter.
  • thermocouples which are distributed on the shell, on the main steam and reheated steam valves and on the pipingintras.
  • the DAS decides in each interval of control which zones should have voltages and which ones should not. Based on this information it gibes orders of activating the relays corresponding to the resistances of the selected zones.
  • the DAS shows all the electric signals proceeding from sensors upon a specific frequency, it digitizes said signals and converts them into engineering units, it further updates them automatically and presents them using the screen, the printer and the plotter. Its function also consists of supplying data to the system in order to control the heating power which is to be applied to the exterior shell, and identifying faults when some anomalous circumstance is produced due to erroneous temperature signals, activating alarms and even disconnecting completely the resistances when the number of the erroneous thermocouples reaches a predetermined value.
  • the DAS provides thus everything that is strictly necessary for the control of the heating blankets, and permits to follow the development of the thermal and mechanical state of the turbine in a start-up, during a normal operation or during the cooling after the triggering of the machine.
  • the outer surface of the turbine is divided into zones. Such zonal distribution is caused by the different characteristics which the surface of the turbine presents (thickness, use of pipings, etc). Each zone may have one or various resistances due to different heating requirements of each zone, although there exists only one thermocouple for the control of each zone.
  • Each control cycle is the period of time which has elapsed between two consecutive samplings and presents two clearly different parts.
  • the control system thus regulates the space and time distribution of the heating power applied to the outer shell with the basic objective of maintaining said shell at a temperature so that a sufficient temperature for a "warm” start-up is assured in the rotor of the turbine.
  • Figure 1 shows a diagram of installation of the system for maintaining warm high power turbines, the object of the invention.
  • Figure 2 shows a detail of installation of the heating blankets over the external surface of the turbine with electric heating elements and a thermocouple.
  • Figure 3 shows a block diagram representing the function of zonal control of the system.
  • Figure 4 shows a block diagram representing the "on-off" control strategy with master PID link.
  • Figure 5 shows the response of the system with respect to a simulation with the thermal and dynamic model in heating condition from ambient temperature.
  • Figure 6 represents the response of the system with respect to a simulation with the thermal and dynamic model in cooling condition from the triggering condition.
  • Figure 7 shows a front view of a device for installation, securing and pulling out a thermocouple.
  • Figure 8 shows the qualitative behaviour of the master PID link strategy in heating condition from ambient temperature.
  • Figure 9 shows the qualitative behaviour of the master PID link in cooling condition from the triggering condition.
  • Figure 10 represents a real situation of a cooling cycle of the internal metal of the trubine from a disconnection from the network resulting from a triggering and the response of the system for taking the temperature to the set point.
  • Figure 11 represents the temperature variations on the surface of the turbine and the response of the control system.
  • the system, object of the present invention consists of a turbine (1) on the exterior surface of which there are a number of resistances (2) in order to carry out the heating function and a number of thermocouples (3) which serve for acquiring data as for the state of the machine.
  • the data acquisition and control equipment (4) consists of a computer with its peripheral equipments.
  • the system also has equipments for supply of electric energy which essentially comprises a transformer (5) and a switching module (6).
  • the disposition of the heating blankets (7 and 8) can be observed as well as the resistances (2) a thermocouple (3) and the enveloping corrugated mesh (9) inside of which a layer of heating blanket (7) and the electric resistance are situated.
  • the isolating assembly is, in a practical case, composed of three layers of detachable blankets (the third layer is not shown in the figure).
  • the thickness of each layer of blankets varies from the first to the third according to the special function of each as for insulating capacity which is required from each one.
  • the enveloping mesh (9) due to its special shape, confers great flexibility to the elctric resistances (2).
  • the blanket is directly installed on the exterior shell of the turbine by means of anchorages soldered to the same and represents the first layer of insulation.
  • thermocouple (3) For the installation of thermocouple (3) a certain type of holder has been designed so that it is perfectly extracable form outside without having to dismantle the blankets while assuring at the same time a permanent contact between the end-point of the thermocouple and the surface to be measured.
  • said holding element consists of a hollow protecting tube (31) of cylindrical shape (see figure 7) which in one end has a tip of conical shape and in the other end presents a flat braodening as of a disc with a slightly larger diameter than that of the tube. Inside said holding element (31) the thermocouple (3) is fitted being protected against possible damages.
  • the signal received by the data acquisition equipment (4) from the thermocouple is adequately processed and as a result allows a code to the zone selection module (6).
  • This code order is given as to which resistances are to be activated by said module.
  • the module decodes the received signal and activates the corresponding solid state relays incorporated in the module. Said relays permit the passing of the current coming from the supply transformer (5) to the resistances through the general switch and the magnetothermics also incorporated in the switching module (6). Finally the selectioned resistances warm up the required zones.
  • the relays it should be mentioned that there is one for each pair of resistances (connected in series) and either allows or closes the passing of electric intensity towards the resistances.
  • DAS data acquisition system
  • a feedback control link is established which has as controlled variable the surface temperature measured by the thermocouple of the zone, and as manipulated variable the heating power yielded by the blankets in said zone.
  • the set point may be local or remote, according to the implemented strategy, but it is always the same for all zones of the outer shell, and it is equal to the outer shell temperature which is necessary for reaching the sufficient temperature in the rotor for a warm star-up, when a steady condition has been reached.
  • FIG 3 the zonal control process is shown in which it can be observed that on the basis of the information received from the thermocouple and the one established by the set point (TSET) on the one hand and the corresponding zone temperature (TEMP1) on the other, the control computer sends the pertinent orders through the energy supply equipment to the heating blankets (blanket), turning on and off the resistances according to each case, which results in a temperature adjustment in the surface zones of the shell (zone).
  • This new temperature (TEMP2) is detected by the thermocouple corresponding to the zone which sends the respective signals to the computer.
  • the control cycle is the period of time elapsed between two consecutive samplings. It presents two clearly differenciated parts: One part for data acquisitions, checking and calculations by means of control algorithms during which the blankets are disconnected in order to avoid interferences with measuring signals; and a second part available for the heating which is terminated by the next sampling instant.
  • the control algorithm calculates in each cycle the fraction of time of the cycle during which each blanket has to be connected; in this manner, the average heating power for each zone in each cycle is regulated.
  • the control system regulates the space and time distribution of the heating power applied to the external shell with the basic objective of maintaining said shell at a temperature such that a sufficient temperature for a "warm” start-up of the turbine is assured in the rotor.
  • the strategy of control permits that the natural cooling process isstopped from any triggering condition, or permits for the heating of the turbine from the ambient temperature until a technical state which would allow a warm start-up.
  • Figures 5 and 6 show the qualitative behaviour of this strategy, obtained with a simple model of simulation of the turbine.
  • This strategy is specially indicated for stopping the cooling off of the machine after a triggering as long as the temperature to be maitained in the outer shell so that the rotor is at SOAK temperature is previously known; or for the cases in which the desired temperature for the rotor does not change and that the changes in the ambient temperature are not excessive.
  • control system is capable of finding, by itself, the set point for the zonal control links corresponding to the outer shell of the turbine. Additionally the power that the blankets yield is modulated as a function of the differential expansion measured at each moment.
  • Figure 4 shows the block diagram corresponding to this strategy.
  • the master link controls the temperature of the rotor manipulating the set point of the zonal links.
  • the control algorithm contains proportional, integral and derivative actions.
  • the control changes the set point of zonal links while there exists a difference between the desired temperature for the rotor and the measured temperature by means of a thermocouple, which assumes (simulates) the temperature of the rotor.
  • a thermocouple which assumes (simulates) the temperature of the rotor.
  • the rotor will have the desired temperature and the output of the controller will indictate the surface temperature required in such conditions.
  • the power modulator permits the machine to reach an elevated heating velocity limiting at the same time the differential expansion.
  • the system starts up with the maximum specified power in order to later reduce it as a function of the measured differential expansion.
  • the applied power is eliminated before reaching the triggering limit, which makes it impossible for such limit to be reached.
  • FIGS 8 and 9 show the qualitative behaviour of the strategy of master PID link.
  • the strategy "on-off" in zonal links eliminates the cover-base temperature difference and takes the surface temperature to the set point calculated with the master PID link.
  • the master PID link takes the temperature of the rotor to the desired temperature for a warm start-up.
  • the power modulator reduces the initial velocity of the heating in order to limit the differential expansion.
  • system object of the invention which is essentially designed to be applied in high power steam turbines is perfectly compatible for application in every type of turbines being especially appropriate in units whose functions are :

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Turbines (AREA)
EP19920907519 1991-03-26 1992-03-25 Verfahren zum Warmhalten von Turbinen Withdrawn EP0537307A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ES9100793 1991-03-26
ES9100793A ES2029430A6 (es) 1991-03-26 1991-03-26 Sistema de mantenimiento en caliente de turbinas de gran potencia, principalmente de turbinas de vapor.

Publications (1)

Publication Number Publication Date
EP0537307A1 true EP0537307A1 (de) 1993-04-21

Family

ID=8271845

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920907519 Withdrawn EP0537307A1 (de) 1991-03-26 1992-03-25 Verfahren zum Warmhalten von Turbinen

Country Status (3)

Country Link
EP (1) EP0537307A1 (de)
ES (1) ES2029430A6 (de)
WO (1) WO1992017687A1 (de)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998055738A1 (en) * 1997-06-05 1998-12-10 Dynatrend Asa A method in or relating to the start of a power turbine and arrangement in power turbine in order to avoid start damage on turbine wheel/housing
EP1674667A1 (de) * 2004-12-21 2006-06-28 Siemens Aktiengesellschaft Verfahren und Vorrichtung zum Aufwärmen einer Dampfturbine
US20110167820A1 (en) * 2010-01-12 2011-07-14 Mikael Fredriksson Heating system for a turbine
WO2012119839A1 (de) * 2011-03-04 2012-09-13 Siemens Aktiengesellschaft Dampfturbine insbesondere für solarthermische kraftwerke
US8347598B2 (en) 2011-03-18 2013-01-08 General Electric Company Apparatus for starting up combined cycle power systems and method for assembling same
CN105003305A (zh) * 2015-06-02 2015-10-28 苏州巨能发电配套设备有限公司 一种汽轮发电机整体机座及其装配工艺
DE102014220370A1 (de) 2014-10-08 2016-04-14 Siemens Aktiengesellschaft Warmhalten einer Dampfturbinenwelle mittels Induktion
DE102014220492A1 (de) 2014-10-09 2016-04-14 Siemens Aktiengesellschaft Vorrichtung zum lokalen Wärmeeintrag an einer Turbinenwelle
DE102014221563A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
DE102014221676A1 (de) 2014-10-24 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken: Einsatz von Inertgas
DE102014221566A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken mithilfe eines Wärmespeichers
US9404380B2 (en) 2013-04-30 2016-08-02 General Electric Company Turbine thermal clearance management system
DE102015206320A1 (de) 2015-04-09 2016-11-10 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
US10174639B2 (en) 2017-01-31 2019-01-08 General Electric Company Steam turbine preheating system
US10337357B2 (en) 2017-01-31 2019-07-02 General Electric Company Steam turbine preheating system with a steam generator
US11603773B2 (en) 2020-04-28 2023-03-14 General Electric Company Turbomachinery heat transfer system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE356074A (de) * 1927-11-26
DE945027C (de) * 1941-12-30 1956-06-28 Aeg Einrichtung zur Sicherung von Dampfkraftanlagen, insbesondere Dampfturbinen
GB877127A (en) * 1959-04-15 1961-09-13 Napier & Son Ltd Gas turbines
US4584836A (en) * 1985-01-29 1986-04-29 Westinghouse Electric Corp. Steam turbine restart temperature maintenance system and method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9217687A1 *

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998055738A1 (en) * 1997-06-05 1998-12-10 Dynatrend Asa A method in or relating to the start of a power turbine and arrangement in power turbine in order to avoid start damage on turbine wheel/housing
EP1674667A1 (de) * 2004-12-21 2006-06-28 Siemens Aktiengesellschaft Verfahren und Vorrichtung zum Aufwärmen einer Dampfturbine
US20110167820A1 (en) * 2010-01-12 2011-07-14 Mikael Fredriksson Heating system for a turbine
US8695342B2 (en) * 2010-01-12 2014-04-15 Siemens Aktiengesellschaft Heating system for a turbine
EP2351912B1 (de) * 2010-01-12 2019-05-15 Siemens Aktiengesellschaft Turbine mit Heizsystem, zugehörige Sonnenenergieanlage und Betriebsverfahren
WO2012119839A1 (de) * 2011-03-04 2012-09-13 Siemens Aktiengesellschaft Dampfturbine insbesondere für solarthermische kraftwerke
US8347598B2 (en) 2011-03-18 2013-01-08 General Electric Company Apparatus for starting up combined cycle power systems and method for assembling same
US9404380B2 (en) 2013-04-30 2016-08-02 General Electric Company Turbine thermal clearance management system
DE102014220370A1 (de) 2014-10-08 2016-04-14 Siemens Aktiengesellschaft Warmhalten einer Dampfturbinenwelle mittels Induktion
DE102014220492A1 (de) 2014-10-09 2016-04-14 Siemens Aktiengesellschaft Vorrichtung zum lokalen Wärmeeintrag an einer Turbinenwelle
DE102014221563A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
DE102014221566A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken mithilfe eines Wärmespeichers
DE102014221676A1 (de) 2014-10-24 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken: Einsatz von Inertgas
DE102015206320A1 (de) 2015-04-09 2016-11-10 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
CN105003305A (zh) * 2015-06-02 2015-10-28 苏州巨能发电配套设备有限公司 一种汽轮发电机整体机座及其装配工艺
US10174639B2 (en) 2017-01-31 2019-01-08 General Electric Company Steam turbine preheating system
US10337357B2 (en) 2017-01-31 2019-07-02 General Electric Company Steam turbine preheating system with a steam generator
US11603773B2 (en) 2020-04-28 2023-03-14 General Electric Company Turbomachinery heat transfer system

Also Published As

Publication number Publication date
ES2029430A6 (es) 1992-08-01
WO1992017687A1 (es) 1992-10-15

Similar Documents

Publication Publication Date Title
EP0537307A1 (de) Verfahren zum Warmhalten von Turbinen
JP4127856B2 (ja) タービンの負荷切替過程を調節するためのタービン制御装置および方法
JP2004522052A (ja) ガスタービンの動作方法
JPS6066048A (ja) 自動的に周期的に調整される経過デ−タに基づいて温水を計画的に加熱するシステム
EP1533482B1 (de) System mit schneller Leistungsproduktion und Methode für Dampfturbine
US4598668A (en) Apparatus for efficiently controlling the operation of parallel boiler units
US4352024A (en) Expander-generator control system
US5367146A (en) Method and circuit arrangement for monitoring and limiting the operating temperature of electrically heated equipment, as well as the use of the method
US4036011A (en) Multiple valve sequential control for a combined cycle power plant
US4506504A (en) Electronic fuel control system for gas turbine
US4583360A (en) Electronic fuel control system for gas turbine
JPH03110304A (ja) ボイラーの自動台数制御方法
JP2544948B2 (ja) ボイラの自動台数制御装置
US4016717A (en) Matching response of a blade path temperature limit signal to characteristics of a gas turbine
JP3559672B2 (ja) 火力発電プラント運転制御装置
US6604491B2 (en) Boiler apparatus
JP2668441B2 (ja) ボイラーの自動台数制御装置における台数制御パターンの自動設定方法
JP2003300121A (ja) ボルトヒータ
JPS6239653B2 (de)
JPS6335231Y2 (de)
JP2845294B2 (ja) 複数台のガス瞬間湯沸器から構成する給湯用熱源装置の制御方法
US4107542A (en) Time delayed relay sequencer and alarm reset for a gas turbine local maintenance controller
SU1134737A1 (ru) Способ регулировани тепловой нагрузки теплофикационной турбоустановки
JPS622129B2 (de)
JP3551496B2 (ja) 貯湯式給湯装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK FR GB GR IT LI NL SE

17P Request for examination filed

Effective date: 19930414

17Q First examination report despatched

Effective date: 19940608

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19961001