Standard Operating Procedure of Boiler and Turbine of

Waste Heat Recovery Unit

Table of Contents

Chapter 01 boiler 1

1.1 Definition of Boiler 1

1.2 Working Principle of Boiler 1

1.3 Monitoring and tuning up of the boiler 1

1.4 Normal Operation of the boiler 2

1.5 Necessary Step before start up of Boiler 3

1.6 Damper Opening: (cold state) 3

1.7 Damper Opening (Hot State) 4

1.8 Shut Down 5

1.9 Blow Downs 6

1.10 Maintenance of the boiler 7

Chapter 02 Steam Turbine 9

2.1 Turbine Start Up and Operation 9

2.2 Before turbine start up 9

2.3 Starting of Turbine 11

2.4 Shutdown 12

2.5 Operation maintenance and downtime maintenance 13

2.6 Synchronization Process 13

Chapter 01 Boiler

1.1 Definition of BoilerSteam boiler or simply a boiler is basically a closed vessel into which water is heated until the

water is converted into steam at required pressure. This is most basic definition of boiler.

1.2 Working Principle of BoilerThe basic working principle of boiler is very simple and easy to understand. The boiler is

essentially a closed vessel inside which water is stored. Fuel (generally coal) is bunt in a furnace and hot gasses are produced. These hot gasses come in contact with water vessel where the heat of these hot gases transfer to the water and consequently steam is produced in the boiler. Then this steam is piped to the turbine of thermal power plant. There are many different types of boiler utilized for different purposes like running a production unit, sanitizing some area, sterilizing equipment, to warm up the

surroundings etc.

1.3Monitoring and tuning up of the boiler:The operating conditions of the waste heat boiler are directly related with that of the kiln. To

ensure the stability of the operating parameters and the highest safety of the operation, the close communication with the kiln operators is extremely necessary for the best coordination; meanwhile, the change of the boiler operating parameters, and the operating conditions shall be closely monitored and analyzed for timely tuning and adjustment.

During the operation, the main purpose for the monitoring and tuning is:

Under the normal kiln operating conditions, to tune up the system to keep the normal operation and maintain the normal pressure of the medium, maintain the normal water level by evenly feeding water to the boiler to ensure the steam quality, and ensure the normal operation of the ash handling system.

1. Precaution for the boiler operation:

I. When the boiler is operating, pay attention to the steam pressure, steam temperature, drum level, water flow, feed water temperature and pressure, the exhaust gas temperature at boiler inlet, furnace minus pressure etc. In case there is a change in the exhaust gas flow and temperature at boiler inlet but no effective result after tuning up, timely communication is needed with the related department for an adjustment of inlet gas temperature in order to ensure the boiler safe operation and the stable parameters of the boiler.

II. Walk down inspection: In order to ensure the safe operation, at least 4 walk down inspections shall be carried out for each operation shift. The items included in the inspections are: all the equipment in the boiler building; check of the boiler casing for any damage and air leak of the manholes; check of all the valves for abnormality; check of all the

water level gauges, pressure gauges, temperature gauges for abnormality, check of all the sections and portions of the heating surfaces for soot deposition, wear and tear and check of the boiler flue gas temperature.

III. Continuous recording on the logs. Once per hour logging shall be carried out. The purpose of recording and logging is to analyze the operation condition and overall regularity of loading alteration of the entire systems for better and reasonable operation.

IV. The regular sampling on the boiler feed water, boiler water, blow down water, steam and produced water shall be carried out for chemical analysis to achieve the goal for economical operation.

V. Based on the water quality and the chemical examination. The regular blow down of the boiler convection tubing banks will be executed. The amount of blow down water shall be determined based on the chemical examination result

VI. Feed water samples shall be inspected regularly to ensure the feed water quality.

VII. Regular and rules for shift alternation shall be strictly followed and the clear records shall be kept on the daily logs.

1.4 Normal Operation of the boiler:During the normal operation of the boiler, the water level shall be maintained normal, the pressure stable, and the steam temperature normal. The monitoring of all the equipment and instruments shall be continued to ensure the safe operation.

1) Requirement for the feed water: the boiler feed water shall be de-mineralized and the quality of the de-mineralized waster shall comply with the appropriate national criteria on the water quality.

2) The boiler water shall be kept within 75 mm of normal level, however slight fluctuation shall be considered as normal. If the water level stays fixed, it might indicate a plugging, requiring a washout of the water level gauge

1.5 Necessary Step before start up of Boiler:By field supervisor

Field supervisor should get a detailed round of Boiler Physically.

Inspection doors of Boiler should be properly closed.

Ensure that the level of the water in the steam drum is at half full.

Feed water and steam valves should be in proper working condition.

Dampers should be verified before start up of Boiler.]

Water level should be maintained at required level.

R-O plant operator should be informed for preparation.

Drain valve of steam line should be opened.

Air vent of steam drum should be opened.

Exhaust valve of steam should be opened.

Hammering device of SP boiler should be ready.

By operator

First of all drain, water and steam valve for required operational condition.

Feeding water to boiler by feed pump till half of steam drum.

Keep the boiler vents open until a heavy steam jet is flowing out (until a boiler pressure of about 1 bar is reached).

Co-operating with kiln operator about their required parameter and then opening dampers accordingly.

1.6 Damper Opening: (cold state)When the hot gases temperature at the cooler exhaust is at 150-200ᵒC then

10% inlet damper open

10% outlet damper open

90% by pass damper open

After 30 minutes

When temperature at cooler exhaust is at 200-250ᵒC then

20% inlet damper open

20% outlet damper open

80% by pass damper open

When the temperature at the super heater now reaches up to 400ᵒC then we take the boiler in line because our steam temperature & pressure reaches 310-350ᵒC and 1.2MPa respectively

100% inlet damper open

100% outlet damper open

100% by pass damper closed

According to the careful estimation, opening of the damper with respect to time is enlisted as under:

Sr.No Outlet Inlet Damper (%age) By Pass Damper (%age)

Hot Gas Temperature (ᵒC)

Time(min)

1 10 90 150-200 302 20 80 200-250 453 30 70 250-300 654 40 60 300-350 855 50 50 350-400 1056 100 0 400-450 120

1.7 Damper Opening (Hot State):When there is a stoppage for some hours, then the boiler still carries some temperature &

pressure and in that case how, the damper opening will be executed .It is given as

Sr.No Outlet Inlet Damper (%age) By Pass Damper (%age)

Hot Gas Temperature (ᵒC)

Time (min)

2 20 80 250 153 40 60 300 254 60 40 350 355 80 20 400 456 100 0 450 60

1.8 Shut Down:-The boiler shutdown is depending on the kiln operation on one hand and the boiler operation

on the other hand. Boiler shutdown may proceed in three ways based on how long the shutdown shall last: temporary shutdown, complete shutdown and emergency shutdown.

1. Temporary shutdown and complete shutdown may proceed in the following steps:

I. Open the by-pass flue, and close the inlet gas butterfly valve

II. Watch the water level and continue to make up for the feed water

III. Reduce the boiler pressure to the “0” , and then close the main steam stop valve.

2. Emergency shutdown:

One of the following situations calls for the emergency shutdown (the steps for the emergency shutdown are similar to the temporary shutdown):

i. The water level of the boiler drops down beyond the lowest limit of the specified level range;

ii. Water level continues to drop down despite the increased water feeding or other necessary action for water filling;

iii. The water level of the boiler rises beyond the upper limit of the specified level range;

iv. Feed water equipment is all in malfunction.

v. Failure of all the instruments such as the water level gauges, pressure gauges and safety valves.

vi. Serious damage to the boiler walls, steel structure overheated purling the safe operation of the boiler.

vii. Explosion or burning in the flue, severely threatening the safety of the boiler and personal life.

viii. Kiln requires boiler emergency shutdown

ix. Other abnormality requires the emergency shutdown of the boiler because of the safety limits are exceeded.

Whenever there is a shutdown taken, the drains of steam lines are opened but the water should be there in the boiler so that shrinkage and other metallurgical effects can be avoided. Also the steam drum is filled with water, Hence the rusting effect is avoided to a larger extent.

On the other hand, when there is a planned shut down and tubes are to be replaced, and then boiler should be cooled down slowly under normal parameters. When the temperature goes down to the required or optimum value (40-50ᵒC) then drains will be opened followed by the cutting of the tubes for replacement.

1.9 Blow Downs:-a. Regular blow down shall be carried out when the boiler is operated at a low load, at least

once per shift. In addition, more blow downs may be applied in consideration of the dosing and the boiler water quality.

b. Before each blow down, the check with the piping and the valves for abnormal conditions shall be conducted. Besides, the water level shall be adjusted to about 35 mm higher than normal, and each blow down shall be controlled such that the water level drops down by about 35 mm.

c. Neither long lever, nor hammer is allowed to forcedly open the valve or peen the valve to prevent the dangers. When two or more than two boilers share the same blow down header, the simultaneous blow downs for these boilers are strictly prohibited.

(They are installed on the headers and points)

Limitations:

4-5 tons water is wasted for blow downs.

Dozing:

To attain parameter standards in boiler

To avoid scaling, corrosion

To improve efficiency

For smooth turbine operation

Drum:

Ph – sphate (5-20)

Alkalinity (OH +ve)

PH (10-12)

Hardness Removal Nil

To Remove O₂ (‹.005)

For passivation of all boiler surfaces.

Drain valves are closed now

Auxiliary oil pump stops, now the turbine is ready to be synchronized with the power plant.

Oil Pressures:

Lubricating oil pressure = 0.30MPa

Control Oil Pressure = 0.9MPa

Oil Temperature Inlet = 40~50ᵒC

Oil Temperature Outlet= 35~45ᵒC

Oil temperature should not be less than 35ᵒC

Maintain De-Aerator Vacuum = -0.080MPa

Maintain Condenser Vacuum = -0.085~ -0.090MPa

Check vibrations of turbine front Bearing , turbine rear Bearing limits= 2~22µm

Bearing Temperature should be 40~70 ᵒC

Axial displacement limits should be between (-0.3 ~ +0.3)

Condenser Hot level should be from (424 ~ 464mm)

1.10 Maintenance of the boilerAfter 5-6 months of the boiler operation, the boiler should be down for maintenance.

(1) To clean off the deposits in the drum, headers of the boiler

(2) To clean off the soot on the heating surface.

(3) Inspection on the internal or external sections of the boiler, such as check of the welds of the pressure parts and steel sheets for corrosion. Severe defects shall be subject to immediate remedy action. If the suspicious defects are located but not impacting the safe operation, records shall be taken for future reference.

(4) Check the induced draft fan for bearing abnormality, check the impeller and the casing for wears and tears. The user shall keep sufficient spare parts for the impellers.

(5) Some portions of the boiler walls can be removed for thorough inspection, if necessary. When the inspection locates the serious damage, the complete repair has to be carried out before start up. All the findings from the inspection and the repairs after the inspections shall be entered into the boiler safety technical logs.

(6) Preservation for the boiler out of service for a long time:

a. Water preservation: fill up the boiler with the treated water, and then boil up the water to remove the air. Fully close all the doors and openings. Or fill up the boiler with the de mineralized water of high alkalinity to prevent the corrosion. The chemicals added into the de mineralized water usually are NaOH (2kg/mᶾ) or Na₃PO₄ (5 kg/mᶾ), and that added into the boiler water are NaOH (5 kg/mᶾ) or Na₃PO₄ (15-20 kg/mᶾ). This method is only for short time shutdown preservation with the heating surfaces and the boiler walls properly dried.

b. Pressure preservation: After removal of deposits from inside the boiler, all the valves shall be closed. Preservation solution is to be added up to the lowest point of boiler outlet header. Heat up the boiler to create a pressure of 0.1-0.2MPa, and then hold the pressure for 2-3 hours. After pressure is dropped down, the

preservation solution should be used again to fill up the boiler, and then keep the pressure of 0.2MPa by using a hydraulic way. The preservation solution is composed of caustic soda (100mg/L), phosphorus pent oxide (100mg/L), sodium sulfate (250mg/L). During the preservation period, regular inspection for the proper concentration of the solution is required. When the concentration of sodium sulfate is found to be lower than 50mg/L, more of that chemical shall be added to keep the specified concentration.

c. Nitrogen preservation(omitted)

When the boiler is down for a quite long time, the nitrogen preservation can be applied.

Chapter 02 Steam Turbine

2.1 Turbine Start Up and Operation: Start the main auxiliary oil pump for 30 minutes before the turbine starts. Condensate pump

and jet water pump start along with circulating water pump.

Reset turbine and ensure the both ESV are fully opened.

Open boiler stop valve from the headers

Open main stop valve of the turbine

Check steam temperature and pressure are normal.

Push “Run” button at 505 turbine control (turbine will start @ 600rpms limited)

600 rpm are maintained for 30 minutes

After 30 minutes, push ENTER + 1000+ ENTER=1000rpm

At 1000 rpm running time is 90 minutes.

Next Enter+2600+Enter, the rpm will reach 2600 rpm

After 20 minutes, Enter +3000+ Enter, the speed will increased up to 3000rpm.

Before Pushing to the RUN command ensure the DCS system RESET and ALLOW Start Up and 505 system RESET

Reset guarding system , slightly move up the handle of emergency sliding valve, set the pressure of quick stop oil, turn clockwise start up control valve by 90ᵒ(1839). Then start up oil pressure will slowly rise at 0.85MPa. Where quick stop control valve should be twirled counter clockwise. The quick stop oil pressure will slowly rise at 0.85MPa,and then start up control valve should be twirled counter clockwise by 90ᵒ with a result that start up oil pressure should become lower slowly and the closed quick stop valve opens gradually to full extent then

2.2 Before turbine start up:1. Before the start the rigorous inspection must be carried out;

a. Check the systems of vapor , drainage system;

b. Inspect the instrument measuring point must be normal and right;

c. Be sure components should be intact, and rotational part is flexible, non-jam situation. The fastening screws should be tightened. Turning devices to listen carefully to check the sound without friction;

d. Check normal condition of condensing steam system.

e. Check the location of speed control system, the correctness of Emergency Trip throttle position in a release.

2. Warm pipes and hydrophobic

a. Isolation valve open slightly so that the pressure to maintain the tube at about 0.25MPa. heating pipes, the temperature rise rate of 5~ 10 °C/min;

b. Tube wall temperature should arrive 130 ~ 140 °C , in order to speed 0.25MPa/min pressure riser to rise to the provisions of values.

When warm tube, the trap door should open as much as possible so that condensation water can discharge, with the tube wall temperature and pressure rise, a gradual clearance of small hydrophobic door to prevent substantial leakage of steam.

Warming tube Notes:

I. Must be strictly to prevent leakage of steam into the cylinder that can cause rotor deformation;

II. The temperature of the various parts pipeline (such as flange and bolts, etc.) should not different too much;

III. Wall temperature should not less than the corresponding saturation temperature under the pressure.

At the same time, start circulating water pump, then water to the condenser space. Start up condensation pumps and recirculation door, so that condensation water between the exhaust and the condenser can cycle, at last start up the main exhaust opening and the total exhaust device to warm tube.

3. Running the oil cycle and check it

4. Starting condensing steam system, check the vacuum system are in normal conditions.

5. Check the level of following items:

I. cooling tower water level = 2800mm

II. Jet water tank level = 1500mm

III. Oil tank level = 234mm

IV. De Aerator water level = 1600mm

Check all parameters and all drain valves should be opened.

2.3 Starting of Turbine1. Start up disk car devices, keep status to listen to any disc friction sound

2. Wear Emergency throttle

3. Low speed warm up, when warm tube finished, close the trap door. When the vacuum up to 400 ~ 500mm Hg, become the slow gradual warm up, maintain speed at 600rpm around about 20 ~30 minutes. Pay attention to oil temperature that should be at 35 ~ 40 °C, if it too low spur or speed is not allowed.

4. Speed

a. When the unit is operating normally, speed at 200rpm. Near critical speed when the rotational speed (2140 rpm) to accelerate a smooth crossing;

b. Using governor control steam conditioning valve, and speed will be up to rating;

c. A new installation or repaired unit should start up at low speed. When passing the test should do excess speeding security test. Method as follows: when the quick closing valve open, operate WOODWARD505 conditioning units to speed up to hit a critical security devices. Close quick closing valve, at speed below 2900rpm following re wear Emergency Trip throttle, and then allows speed to rated speed;

d. Check the normal operation and the vacuum has reached rating.

5. With Load

a. Speed at 100 kw/min or so to full load speed;

b. Check the normal work conditioning system , hydraulic and oil motivated second opening , load mutual adaptation;

c. Check unit sound, vibration, axial displacement, thrust bearings watts and temperature, differential expansion, steam and metal temperature rise speed, temperature normal;

d. Adjust the water condenser level timely, water level and pressure de-aerator, steam seal pressure, Oil Cooler oil temperature , generator cooling water inlet temperature and pressure, water level changes in the attention of the heater.

2.4 Shutdown 1. Normal shutdown

a. Gradually unload load in order to shutdown, before charge load examinate the pump oil, and the charge rate of less than 100 KW/min;

b. Hand Emergency Trip throttle hand and turn off shoot quick closing valve;

c. Monitor the oil down to 0.08MPa (g), then start the auxiliary fuel pump;

d. Record the time go lazy;

e. Open the steam to the steam valve marshaling, speed to critical speed, then turn off valve to send steam;

f. Open the cylinder and the main steam pipe trap door;

g. After the turbine stop, turn off exhaust device (turn off the exhaust valve first);

h. Regular car plate until steam cool;

i. Rear cylinder temperature is below 50 °C turn off the water cycle;

j. The back oil temperature is below 45 °C, stop lubricating oil.

2. Emergency shutdown

The following situations happen should have an emergency shutdown.

a. Unit speed excess more than 12 percent rating stands;

b. Unit sudden has strong vibration or hear clearly the voice of the internal metal;

c. Turbine seal occurred spark;

d. A bearing unit off oil or smoke;

e. Oil down to 0.05MPa (g), failure cannot be eliminated;

f. Bearing oil temperature more than 75 °C or axial displacement of more than 0.7 mm without automatic shutdown;

g. Turbine oil system fires, and cannot be quickly extinguished, and threat to the safe operation of generating units;

h. Tank oil level down to the lower limit, unexplained oil spill;

i. The main steam or feed water pipe rupture, endangering the safety crew.

2.5 Operation maintenance and downtime maintenance 1. The personal on duty should do the following tasks well during the operation time:

a. Units of heat engine protection device, interlock protection devices, the start switch of the auxiliary should be put at the location;

b. Recording the instrument readings in the daily form per hour. If the readings are abnormal, you should find out the reasons and take some necessary measures;

c. Recording the instrument readings entirely in the monthly form every day, and analyzing the readings according to the operation conditions;

d. Inspecting the units overall per hour. If there are deficiencies in equipment, fill in the equipment defects report form in time and pay attention to the significant deficiency;

e. Measuring, recording and analyzing the various bearing vibration regularly every day.

2. Downtime maintenance

a. If starting immediately after a short period of downtime, lower the load or load rejection gate to fight the emergency shutdown quickly, this can greatly shorten the start up time again;

b. Parking overhaul, make sure reduce the load slowly and operate stably at low load for a certain period of time;

c. Vehicle should always be set, shot term park and start again, in half an hour before start up should be changed regularly for car plate. Unit overhaul downtime, continuous disk first and then changed to regular car plate. Bell gradually increasing time intervals until completely cooled;

d. Long time out, should make the necessary anti corrosion treatment. Hot air drying can be used through flow part of : sealing equipment, such as add lime or calcium chloride desiccant and carefully adjusted bearings and other components of the corrosion prone parts of the anti corrosion treatment, such as surface corrosion resistant material. Pipeline related equipment, instrumentation and all water pipes in a net release. And maintenance during the regular checks are carried out in accordance with the regulations to ensure quality maintenance.

2.6 Synchronization Process: Inform the electrical operator to connect the grid after testing the governing valve tightness and

the emergency breaker activation.

The operator shall focus on the air supply for the air sealing after synchronized, carefully monitor the sound and vibration, also don’t forget to check the bearing oil temperature, the oil pressure of each system as well as the opening of governing/regulating valve. After everything is going smooth, start the turbine protection.

When the generator was synchronized to the grid, emergency trip system should be put in to the practice.

After grid connection, immediately load on 1000kw,for 10 minute and then increase the load to 3000kw at the speed of 150kw/min and maintaining it for the next 10 min. later on increase the load once time to 10000kw of the speed of 150kw/min

It was not recommended to perform no load running if without any special requirements. The generator shall be with 10% rated load at the moment connected with turbine. The back cylinder temperature will be less than 100ᵒC ~ 120ᵒC at no load running and less than 60ᵒC ~ 70ᵒC at no load running

Record all the parameters and on loading duration in the operation log book

Switch off the steam supply valve between the new steam and the bearing gland , and adjust the steam supply based on any steam leakage phenomenon at the turbine end.

Cooling water should be supplied to generator cooler and keep the inlet air temperature around 30~ 40ᵒC, If the inlet air temperature is over 40ᵒC.

Pay attention to adjust the normal position of the condensing water level(1/2 of the water level gauge)

After the condensing water being test to be qualified, switch off the water discharge valve and open the valve to the de-aerator to supply water to the de-aerator.

Open the ejector pump, extract the condenser to vacuum.

Hot start time and vibration values:

R/min Min vibration value (mm)speed accelerated 0~600 3

0.03

warm unit 600 5speed accelerated 1000 3warm unit 1000 10

speed accelerated 2600 5~6

0.10 over the critical state

warm unit 2600 5 0.03speed accelerated 3000 3 0.03

Cold state start procedure:

Operations RPMTime (min)

speed rise to after driven the Rotor 0~600 2~3check and Maintain 600 25~30Smoothly raise speed to 600~1000 2~3check and Maintain 1000 25~30Smoothly raise speed to 1000~2600 5~6check and Maintain 2600 15~20speed accelerated to 2600~3000 2~3 Total 6~95(min)

1. Switch on the AC and DC supplies from LTP Panel.

2. Turn on MK switch

3. Start the DC field from Scada.

4. Check the generator voltage; shown on LTP Panel, when it reaches 6.3KV, generator is ready for synchronization.

5. From computer, select the breaker of generator. Give the synchronization command by clicking on synchronization “start” button

6. On synchronoscope when the Dot reaches the midpoint and turns green, that means voltage and frequency are matched and generator is synchronized.

7. Now turbine operator will start taking the load

8. Maintain the power factor around 0.95.