STANDARD OPERATING PROCEDURE AND SAFETY GUIDE FOR TERRY STEAM TURBINE APPARATUS (Located in Rm. H-17 Head Hall)

Transcription

1 STANDARD OPERATING PROCEDURE AND SAFETY GUIDE FOR TERRY STEAM TURBINE APPARATUS (Located in Rm. H-17 Head Hall) Prepared June 11, 2010

2 Table of Contents 1. Scope Objective Regulations Apparatus Overview and objective Apparatus overview Hazards and control evaluation Possible fire event Ventilation Kinetic, thermal & accoustic Electrical Steam, condensate, oil and Boiling water General, physical & equipment concerns Access Training Personal protective equipment Operation Qualified personnel Experiment preparation Lab instructions Operating procedure Inspections Operational & Periodic inspections Typical test...37 Appendix A: Terry Steam Turbine Theory and Calculations...38 Appendix B: SSCM solid state control module...39 Appendix C: Unfired steam generator...40 Appendix D: Heenan -Froude Dynamometer...41 Appendix E: Terry Wheel Turbine...42 Appendix F: Overspeed Governor...43 Appendix G: Spirax Sarco valve controller...44 ii

3 H-17, Head Hall floor plan Figure 1: H-17, Head hall floor plan 3

4 1. Scope 1.1 Objective This standard operating procedure is intended to provide operating instructions and safety information for the Department of Mechanical Engineering s Terry Steam Turbine experiment apparatus located in H-17, Head Hall. This document is intended as a guideline and supplement to proper training that must be provided by qualified personnel before the apparatus is operated. The aim of this document is to ensure that safe work practices have been developed for the experimental work. This SOP is primarily concerned with the apparatus component s description, operation procedure, hazards involved in the operation and safety precautions that must be taken to avoid injuries. 1.2 Regulations This document has been developed in accordance with the Environmental Health and Safety Office of the University of New Brunswick. 2. Apparatus Overview and Objective 2.1 Apparatus overview The Terry steam turbine uses clean steam generated by the unfired steam generator (USG) to produce power. The unfired steam generator uses steam supplied to the building by the central heating plant as an energy source. The steam supply to the unfired steam generator through a carbon steel steam supply pipeline is controlled by main steam supply valve (with blue lever). The valve is turned to supply steam to the USG and automatic pump trap. The steam supply pipeline is provided with strainers to filter the steam coming from central heating plant and supply filtered steam to the USG and automatic pump trap. There is a digital flow meter gauge mounted on the steam supply pipeline and connected to the electric outlet. It measures the temperature and flow rate of steam in the steam supply pipeline to the USG. There is a supply pressure gauge downstream of the flow meter that measures the steam supply pressure before the control valve. The USG consists of steel tube sheet heat exchanger coils, through which steam flows and transfers heat to the water in USG and clean steam is produced in USG. The condensate of steam on its way to USG is collected in auxiliary trap, if there is any steam condensed in the steam supply pipeline. There is a main trap in USG to collect the steam condensate from steel tube 4

5 sheet heat exchanger coils. The amount of steam into the USG is controlled by an Automated control valve, which is comprised of two port control valve, spring retract actuator and an electronic positioner. This valve is controlled by a secondary controller (Spirax - Sarco) mounted on the SSCM Solid State Control Module. Figure 2: Apparatus components overview 5

6 Figure 3: Control valve 6

7 Figure 4: Apparatus components overview SSCM is a solid state controller designed to control and limit water level, over and under pressures in USG, water feed, alarm, and timed blow down functions for the USG. The SSCM is supplied with a LED backlit LCD display. LED pilot lights are supplied to indicate ON-OFF, high pressure, low pressure, low water, high water, water feed and blow down. The secondary controller for control valve can operate in manual mode as well as automatic mode. This can be achieved by using the keypad & digital 7

8 display provided on the side of SSCM. The alarm of SSCM can be silenced by pressing the ALARM SILENCE key, but the LED pilot lights will still blink to indicate warning. The SSCM also keeps check on the level controller. If the water level in the USG reaches a reduced level then the Feed water pump will be activated. This will raise the water level in the USG until it rises to a satisfactory level, then at this level SSCM will shut the pump off. This is only true if the pump control box switch is set to AUTO mode. If the switch is set to HAND then the feed water pump will run continuously. If the level in the USG continue to drop (for example the feed pump fails or lack of water supply) the low water level alarm will sound and the low water light will flash Red on the SSCM. If a Low water alarm is signaled, power is cut to the secondary controller for the steam inlet control valve and the valve will fail safe close to prevent any more steam entering the USG. The level control float and switches serve two functions:- 1. At a reduced water level it turns on boiler feed water pump until the USG water level is at a correct level then it will switch OFF the pump. 2. At a further reduced level it will sound an alarm and shut off the steam supply. The above is true only if the pump control box is set to AUTO mode. There are gauge glasses/sight glasses on the level controller on USG, feed water reservoir and automatic pump trap providing visual water level estimates. The feed water reservoir also has a float switch and makeup water supply. If the level in the reservoir is too low then a solenoid valve will open to allow fresh water to enter until the proper level is obtained. Then the solenoid valve goes close. It is important that the makeup water valve is open to supply. If USG builds up very high steam pressure inside it, then the pressure relief valve at the top of USG opens automatically and vents some of the steam to decrease the pressure in USG and the SSCM shuts off the control valve to stop steam supply to USG at high pressure alarm. Please refer to Appendix B to see the details of installation, operation and maintenance of Solid state control module. Please also refer to Appendix C to see the details of USG s installation, operation and maintenance instructions, USG s components description, specifications and schematic figures of USG. 8

9 Figure 5: Secondary controller (SPIRAX-SARCO) 9

10 Figure 6: Blow down valves 10

11 Figure 7: Feed water pump and reservior 11

12 Figure 8: Steam turbine USG components 12

13 Figure 9: Apparatus SSCM The flow and temperature of clean steam produced by USG for the turbine is measured by Digital flowmeter. There is an Ellison U-path steam calorimeter along the pipeline to determine the quality of steam entering the turbine. After the calorimeter there is a Turbine inlet pressure gauge. The steam supply to turbine is controlled by the main steam supply valve (red valve), which is opened slowly to supply steam to the turbine assembly upon startup. After initial warm up the valve remains fully open. There is a speed governor and control valve that controls the amount of steam into the turbine. If the turbine overspeeds, the speed governor will reduce the opening of control valve, which will reduce the amount of steam into the 13

14 turbine to control the RPM of the turbine. Conversely the control valve will open further if the RPM drops below its desired level. The RPM of turbine can be noted from the RPM indicator. The steam entering the turbine, passes through a nozzle body inside the turbine assembly. The jet of steam caused by the nozzle, loses a part of its velocity and energy during its first flow across the wheel buckets of terry steam wheel turbine. The steam still has considerable amount of energy in it and passes to a reversing chamber, which returns the steam to the wheel buckets again. This cycle is repeated several times until all of the steam s useful energy has been given up to the turbine wheel. The turbine wheel rotates and transmits its motion to the output shaft, which is connected with the Heenan and Froude dynamometer to determine the power produced by the steam turbine. The power produced by turbine is determined by applying load on the turbine via Heenan and Froude dynamometer. There is a load adjusting wheel on the dynamometer which is turned to apply load on the turbine, and as load is applied the RPM decreases. The applied load is then balanced by turning the weight adjusting wheel so that it makes the RPM constant. The Level indicator on dynamometer tells the user, if the applied load is balanced or not. There is an Analog load indicator on turbine dynamometer that indicates the load taken by the turbine. The terry steam turbine is also provided with oil for lubrication purpose. There are oil caps on the turbine, which can be lifted and oil can be poured into the oil tanks. The oil sight glass indicates the oil level in turbine to the operator. Please refer to Appendix D and Appendix F to see the details and description of Heenan Froude dynamometer and the overspeed governor. Also please refer to Appendix E to see the details and description of terry wheel turbine. 14

15 Figure 10: Automatic pump trap 15

16 Figure 11: Apparatus components overview 16

17 Figure 12: Dynamometer Level Indicator 17

18 Figure 13: Apparatus components overview After removing all the useful heat of steam to produce power, the turbine exhausts the steam into the condenser unit, which condenses the steam and pumps it via automatic pump trap to the feed water reservoir. The condenser unit consists of a shell and tube heat exchanger, with water flowing on the tube side and exhausted steam on the shell side. The condenser unit has a pressure relief valve installed on it to release the pressure of condenser, if an over pressure develops in the condenser. There are three thermo couples connected to a rotary switch and a digital display to monitor turbine outlet steam temperature, condenser cooling water inlet and outlet temperatures. There is also a condenser water flow meter and digital 18

19 display. The automatic pump trap has a valve opening for the condensate from condenser, condensate to the reservoir, motive steam into the pump and vent line. If the condensate level in pump trap reaches a high level, which can be witnessed by the gauge sight glass, then the pump will open the motive steam inlet valve in order to develop pressure necessary to pump condensate into the feed water reservoir and close the condensate inlet valve until the condensate level in pump becomes normal. If high pressure builds up in the automatic pump trap, then the vent valve on the top of pump trap opens up to vent the steam into the exhaust located outside room H-17. There are number of vent valves, pressure relief valves, isolation valves and strainers mounted on the apparatus for safety purposes. Figure 14: Apparatus components overview 19

20 3. Hazards and Evaluation:- 3.1 Possible fire event The apparatus is associated with high temperatures and high pressures. In the event of fire, evacuate the room immediately. Pull the nearest fire alarm (see H-17 floor plan in figure 1). Should you return to attempt to extinguish the fire, do not do so alone and make one attempt only and if unsuccessful leave immediately. If successful stay at the scene and have someone alert Security (ph. # 4830) and Campus Safety (ph. # 5075). Please refer to Figure 1 (H-17, Head hall floor plan) to see the locations of fire extinguishers, fire alarm pull station and phone. 3.2 Ventilation Ventilation fans and ductwork are installed such that there shall be fresh air introduced into the room (green duct) and ambient air exhausted from the room (teal duct) at all times the room is occupied. These fans are controlled by wall switches locally (see Figure 15) but are on over-ride controls controlled by Facilities Management (FM). If at any time the fresh air supply or room exhaust fans are not working contact FM immediately (ph # 4889). There is a household CO monitor mounted on the north pillar. Ensure that it is operational by observing the moving LCD display. Figure 15 displays the ventilation controls of H-17 lab. 20

21 Figure 15: Ventilation controls 3.3 Kinetic, Thermal and Acoustic The moving parts associated with this apparatus are the load adjusting wheel, static weight, weight adjusting wheel and the output shaft on which the terry wheel turbine is mounted and they do not pose any serious moving threat if handled carefully. There is a meshed gears assembly underneath the load adjusting wheel to transmit the motion of load adjusting wheel to the dynamometer. While turning the load adjusting wheel, be careful and keep the fingers of your hands away from the meshed gears assembly as meshed gears are also rotating and are made of heavy thick steel. 21

22 The applied load on the engine is balanced by a static weight hanging by a spring (see figure 12). The weight adjusting wheel and the hanging static weight does not pose any kinetic threat if handled carefully during the operation. The output shaft mounted on the terry wheel turbine and connected to the dynamometer however poses serious threat. Body parts should be kept away from the shaft while the engine is running. The output shaft is in a safe casing but should be dealt with carefully to avoid serious accidents. Also make sure that the shaft is clear of everything before operating the apparatus. Do not wear loose clothing and keep hair tied back. Figure 16: Kinetic hazards description 22

23 The apparatus poses serious thermal hazards if not handled carefully. The apparatus uses steam to produce clean steam in USG, and the steam passing through steam supply lines heat up the supply lines to high temperatures. Once the main steam supply valve is opened, steam supply lines of the apparatus should not be touched without wearing gloves, because it can cause serious burns. The USG, terry turbine wheel and condenser unit are also associated with high temperatures and any part of these components should not be touched while they are in operation to avoid thermal hazards. If the user feels necessary to touch steam supply line, condensate line, USG, terry turbine wheel or condenser unit then he should wear safety gloves to do so. The condensate lines are also very hot and should not be touched without wearing safety gloves. The apparatus is a little noisy but it does not pose any acoustic threat, however if there is any other equipment being operated in H-17 room while using the terry steam turbine apparatus and it requires hearing protection then disposable earplugs are to be worn by students, instructors and all other room occupants. Instructors are responsible for relaying this information onto all involved. The location of the earplugs in room H-17 is indicated in the room layout plan in figure 1. 23

24 Figure 17: Thermal hazards 3.4 Electrical There are no electrical hazards associated with the apparatus, if it is handled carefully. The electric power supplied components of the apparatus are digital display gauges, thermocouples, flow meter, electric pump and SSCM and does not pose any electric threat to the user. The thermocouples, SSCM and electric pump of the apparatus should be checked regularly for bare or cut electrical wires every time before operating it to prevent the user from electrical threats. 24

25 Figure 18: Electrical hazards 25

26 Figure 19: Electrical hazards 26

27 Figure 20: Electrical hazards 27

28 Figure 21: Electrical hazards 28

29 3.5 Steam, condensate, oil and Boiling water The steam, condensate and boiling water are at high temperatures and heat up the components of the apparatus. Any component of the apparatus should not be touched, while it is in operation as it can cause serious burns. The user should wear safety gloves, If he/she wants to touch any component of the apparatus while it is in operation. Oil is used to provide lubrication to the terry wheel turbine output shaft, overspeed governor and other mechanical components of the apparatus and is poured into the oil tank by lifting the oil cap on the turbine. 3.6 General, physical and equipment concerns The experiment is associated with high temperatures and high pressures. The SSCM ensures the safety of user by automatically controlling the high pressure and low pressure alarms, water feed, water level alarms, control valve and electric pump. The SSCM alarms the user of any problem and performs the required operation automatically to overcome the problem. 3.7 Access All personal in the H-17 laboratory should be preauthorized by the faculty in charge or under the supervision of authorized personal (lab technician or teacher assistant). No person other than the faculty in charge or specifically authorized personal are permitted to make alterations to, or run experiments with the terry steam turbine apparatus. 3.8 Training All individuals using the apparatus shall be required to receive training in the proper operation and maintenance of the apparatus and its controls. Training will include such topics as the complete operation and controls of the apparatus. Training programs shall be administered by qualified personnel at UNB. 3.9 Personal Protective Equipment Following personal protective equipment is optional to wear while doing this experiment: hand gloves pair safety goggles 29

30 Figure 22: Oil (for turbine lubrication) 4. Operation 4.1 Qualified Personal These notes in the operation section will provide a guideline to the individual that has been trained by a qualified personal to operate the terry steam turbine apparatus. Only after the individual has been trained and feels confident with the apparatus operation and experiment procedure should he attempt to operate the apparatus using these notes. Do not proceed if you are not properly trained or are unsure in any manner of the safety operation and safety concerns. 30

31 4.2 Experiment preparation/startup Following steps should be carried out to prepare for the experiment:- Ensure that the apparatus physical integrity is not compromised (cut thermocouple electrical leads, bare SSCM or electric pump wires, crack/leaks in USG and leaks in condenser Ensure that there is enough oil in the turbine by looking at the oil sight glass Ensure that there is no substance/material lying on the turbine and dynamometer Check that there is no heavy object lying on the top of USG, as it can cause an increase in undesired pressure in USG during the operation, which can be dangerous Ensure there is no load on Dynamometer wheel (Turn fully CCW) Open the water flow to the dynamometer and condenser by opening the main water supply valve (see figure 24), so that the water temperature in condenser reaches a steady temperature and there is a steady water flow in the dynamometer before operating the apparatus Ensure make up water valve is also open 4.3 Lab Instructions Instructor Responsibilities: The apparatus (SOP) should be read and understood. This document provides all the necessary information regarding the experiment procedure, operation, hazards involved & safety precautions to be taken while using this apparatus. The lab instructor shall remain in the room while the experiment is in progress. After the full students group has assembled and before any explanation has begun the instructor should relay all safety precautions and hazards as outlined in section 3. Inform them that they must contact the instructor should any problems or concerns arise during the experiment. Make the group aware of the fire extinguishers location, fire alarm pull 31

32 station, phone and exits. Any student from the group missing his any personal protective equipment should not be allowed by the instructor to enter the room H-17 and proceed with the experiment. Figure 23: Water flow to dynamometer and condenser 32

33 Figure 24: Main water supply valve Data/Instruments Locations and Functions The location and function of the data instruments of the apparatus is given below as follows: Digital flow meter display gauges mounted on the steam supply lines (see figure 2) measure and display the flow rate and temperature of the steam SSCM and secondary controller monitored pressure display (see figure 5) displays the set point and acquired pressure of the USG 33

34 Analog pressure gauges mounted at various locations on the apparatus - measure and display the pressure of the steam or water Thermocouples mounted on the condenser unit (see figure 18) measure the temperature of steam entering condenser, water entering condenser and water leaving condenser Digital temperature display (see figure 18) displays the temperature measured by the thermocouples and temperature display controlled by temperature dial knob Water flow meter (see figure 18) measures and displays the flow rate of water entering and leaving the condenser unit Steam calorimeter temperature 4.4 Operating Procedure Experiment procedure After preparing for the experiment and following all the steps mentioned in section 4.2 to prepare for this experiment, follow the following steps to complete the experiment:- Open the water supply valve to condensate reservoir (the green lever valve in figure 25) Switch on the flow meters and digital display gauges Turn on the feed water pump switch to auto position Power on the SSCM and the secondary controller and put it in manual mode first to increase the pressure gradually. Set initial opening to almost 30 %. If the water level in USG is still low, then the SSCM will stay powered off to cut off steam supply and will let the USG fill up with water to a certain designed level Then open the main steam supply valve slowly (Blue lever valve in figure 2). Just crack the valve and let the USG coils warm up for 10 minutes and double check that the water supply valve to feed water reservoir is open (see figure 25) Increase the pressure of steam in USG slowly by using the keypad on SSCM (see figure 5). When the pressure of steam reaches almost 34

35 70 psi, then put the secondary controller in automatic mode by setting a desired pressure value usually 80 psi After setting a pressure value in USG, open the main steam valve (red valve in figure 11) slowly to let the steam into the terry wheel turbine to warm up turbine slowly When the pressure in USG reaches user set value, then open the main steam valve (red valve in figure 11) completely and let the turbine rotate until it reaches a constant R.P.M Then apply the load on turbine wheel by rotating the load adjusting wheel and balancing the load by static weight to make turbine wheel rotate at constant R.P.M Figure 25: Water supply valve to condensate reservoir 35

36 4.4.2 Normal Shutdown Shut off the apparatus by closing the main steam supply valve (blue lever valve) Let the turbine wheel run until the maintained pressure in USG is reduced to zero Keep the track of pressure in USG by looking at the digital display of secondary controller (see figure 5) When the pressure falls down to zero in USG, then remove the load from dynamometer and switch off the SSCM Turn off the feed water pump Close the water supply to the apparatus by closing the main water supply valve (see figure 24) Emergency Shutdown 1. Shut off the apparatus by closing the main steam supply valve (blue lever valve) 2. When the pressure falls down to zero in USG, then remove the load from dynamometer and switch off the SSCM 3. Turn off the feed water pump 4. Close the water supply to the apparatus by closing the main water supply valve (see figure 24) 5. Let the turbine wheel run until the maintained pressure in USG is reduced to zero 6. Keep the track of pressure in USG by looking at the digital display of secondary controller (see figure 5) 36

37 5.0 Inspection Inspections at regular intervals will be performed on the apparatus to ensure that the apparatus is kept in a safe and well maintained condition. The inspection includes checking of any leaks and cracks in USG, steam and water pipes, traps and valves and regular checks for bare & cut electrical wires in the apparatus. 5.1 Periodic & Operational Inspections Visual inspections are the responsibility of the person who is conducting experiments on a regular basis with the terry steam turbine apparatus and should be carried out everytime before operating apparatus. A complete periodic inspection of the apparatus shall be performed by the person who is conducting experiments on a regular basis with this apparatus but will alert the faculty in charge in case of any deficiencies in the apparatus. The deficiencies such as those listed below shall be examined during both the periodic & operational inspection and the faculty in charge will determine if the deficiencies will affect the safe operation of the apparatus. Contact Boiler inspector for annual and semiannual inspections. a. Worn, cut or bare electrical wires b. crack, leaks and worn/corroded surface of USG, traps, condenser, steam supply lines, valves and water pipeline 6.0 Typical Tests The actual test procedure will be outlined in the lab script as issued by the professor. A typical test includes recording the actual load, steam line pressure, steam line temperature, RPM of turbine, steam flow rate into the terry wheel turbine, turbine exit temperature and pressure, steam calorimeter temperature, condenser inlet and outlet temperature and condenser water inlet and outlet flow rates. Please refer to Appendix A to see the lab script and details of theory and calculations involved in the experiment. 37

38 Appendix A 38

39 Appendix B 39

40 Appendix C 40

41 Appendix D 41

42 Appendix E 42

43 Appendix F 43

44 Appendix G 44