reading / VA1-BWBC-00100-PM-M1A-CTP-0003

1 General Information

1.1 Purpose

It is to investigate the index of boiler performance of Vung Ang Power Plant 1 Vietnam and to check the thermal efficiency of boiler and air leakage rate of air preheater under rated load. Meanwhile it provides necessary experience and information for the boiler to reach the best running status.

This test will be carried out with turbine performance test at the same time.

1.2 Equipments Specifications

Vung Ang Power Plant 1 uses W type subcritical boiler with balanced draft and Carolina drum from Babcock & Wilcox Beijing Co., LTD. The designed coal is Vietnam anthracite coal. There are 24 Half-PAX burners in the boiler (each 12 at both front and rear wall). 6 ball mills are equipped and each ball mill has 4 burners.

The boilers each have a Maximum Continuous Rating main steam flow of 2,028 ton per hour at 541°C and 17.43 MPa with a reheat steam flow of 1658 ton per hour at 541°C and 3.833 MPa. The Turbine Rated Load main steam flow is 1,853 ton per hour at 541°C and 17.29 MPa with 1529 ton per hour reheat steam flow at 541°C and 3.558 MPa.

Main steam temperature is controlled by two stages of spray attemperater. The first stage of attemperater is located between the primary superheater (Pri-1) outlet and the inlet of the radiant platen superheater (Pri-2). The second spray attemperater is located at the inlet of the secondary superheater. Reheat steam temperature is controlled by gas biasing between the reheat and superheat gas passes of the convection pass. Spray attemperater is present at the inlet piping of the reheater header for temperature control during load swings and emergencies.

Combustion air is supplied by two axial FD fans. Primary air is supplied by two axial cold primary air fans. Both primary and secondary air streams pass through two Ljungstrom tri-sector regenerative air heaters. The unit is also equipped with 2 axial induced draft fans located downstream of the electrostatic precipitator.

Designed parameters of boiler are listed below.

Note: 1) g for gauge pressure.

2) For dry flue gas at standard condition (273K, 101325Pa) with the O2 volume content of 6%.

1.3 Air Preheater Specification

Designed parameters of air preheater:

1.4 Designed Data

Boiler efficiency at 100%RO based on LHV,90.1%.

Air heater leakage at 100% RO. shall not exceed 7% within the first year, and shall not exceed 8% after one-year operation.

2 Reference Standards and Documents

As contracted, the boiler thermal efficiency test will be performed according to the ASME performance test standards. The boiler efficiency is calculated by indirect heat balance (heat loss).

The air leakage test for boiler air preheater will be performed according to the ASME performance test standards. The applicable standards are as below:

ASME Codes for Performance Test

ASME PTC4.3 1968 Air Heaters Codes for Air Preheater Test

3 Work Plan and Schedule of Trial Running

The whole plan for boiler performance test is scheduled to about half a month, every morning overall soot blowing and other preparations, and every afternoon performing tests. The test will be postponed in case of interruption. Test plan is as in below table:

*The boiler guarantees value is verified by the formal test at 600MW load and 75% load is reference for the owner.

4 Performance guarantees

4.1 The gross efficiency of boiler based on HHV will be 87.5% (90.1% base on LHV) at 100%RO and 90.3% (LHV basis) at 75%RO, when the following items are all met:

1)boiler operate stably at 100%RO and 75%RO;

2)firing performance coal;

3)air relative humidity is 95%, with the ambient temperature of 25 ;

4)barometric pressure is 0.1013MPa;

5)boiler blowdown is 0%;

6)the pulverized coal flow deviation between each pulverizer’s four primary air ducts is

no more than ±10%, and the air flow deviation is no more than ±5%;

7)pulverized coal fineness of R90 is less than 6%(for each pulverize coal duct), R200 is less than 0.193%(for each pulverize coal duct);

8)boiler gross efficiency is calculated according to ASME PTC4.1, and is corrected with the correction curves( see Appendix 8.4).

4.2Air leakage of air heater shall not exceed 7% within the first year, and not exceed 8% after one year operation, guarantee conditions are:

1)boiler operate stably at 100%RO;

2)firing performance coal;

3)excess air keep at design value;

4)pulverizing system parameters meet the requirements of boiler;

5)air leakage of air heater is calculated according to ASME PTC4.3.

4.3The pressure drop from the boiler economizer inlet to the super heater outlet is no more than 1.72MPa, when the following items are all met:

1)boiler operate stably at 100%RO;

2)firing performance coal;

3)main steam, reheat steam and feedwater parameters keep at rated value;

4)feedwater quality meets the requirement.

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4.4 The pressure drop from the boiler reheater inlet to the reheater outlet is no more than 0.41MPa, when the following items are all met:

1)boiler operate stably at 100%RO;

2)firing performance coal;

3)main steam, reheat steam and feedwater parameters keep at rated value.

5 Necessary Conditions and Safety Precautions & Warnings

5.1Coal for performance test

It is very important to guaranty the accuracy of the boiler efficiency test that making sure the ingredients of test fuel coal is similar to the designed coal. Coal characteristics and deviation accepted for the boiler performance test is shown in the following table.

Calculation and correction to boiler thermal efficiency will be in accordance with ASME version PTC 4.1 and the correction curves. Industrial and element analysis should be completed in time after coal is sent to site during test preparation period. Coal with different qualities should be stacked separately and the test fuel coal must be allocated and stacked according to requirements from test leading group.

5.2 Measurement Points

Fig.1 shows heat balance boundary of boiler performance test and arrangement of measurement points.

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Fig.1 Boiler boundary and measurement points arrangement Arrangement of measurement points in details are:

(1) Measuring points for flue gas temperature and ingredients analysis:

Temperature at economizer outlet duct( preheater inlet), location 16: the existed test points, grid, 10×4×2 points;

Oxygen content at economizer outlet duct(preheater inlet), location 16: the same as the economizer outlet temperature;

Temperature at air preheater outlet duct(location 17): the existed test points, grid, 10×4 ×2 points;

Oxygen content at air preheater outlet duct(location 17): the same as the air preheater outlet temperature;

(2) Measuring points for ash sampling

ESP inlet duct or Air preheater inlet vertical duct, location 3 or 5: existed ash sampling points,2×2 points

(3) Test Point for bottom ash sampling

Blowdown tap of bottom cinder collector, location 8: 1 point

(4) Sampling points for feeding coal sampling

Sampling device at each coal feeder sampling point, location 1, 12×1 points

(5)Measuring points for superheater system pressure drop DCS pressure at separator outlet, location 22: 3x1 points DCS pressure at superheater outlet, location21: 2x1 points

(6)Test points for reheater system pressure drop

DCS pressure at reheater inlet, location 19: 2x1 points DCS pressure at reheater outlet, location 20: 2x1 points

(7) Test points for economizer system pressure drop

Water feeding DCS pressure at economizer inlet, location 18: 1x1 point

5.3 Calibration of Instruments and Apparatus

All the temporary instruments specially prepared for test must be calibrated according to requirements within the time limit. Devices for flue gas analysis should be calibrated with standard gas timely during each operating mode of the test.

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5.4 Checking on System

5.4.1Check and make sure the boiler and its auxiliaries are running normally.

5.4.2Check whether the drain valve and blowdown valve of the steam water system is tight.

5.4.3Check the ash deposit on each heating surface inside the furnace. Proceed a general soot blowing before test.

5.4.4Pulverizer can run normally after adjustment. Fineness of pulverized coal can meet the test requirements.

5.5 Requirements for Test

5.5.1One general soot blowing to boiler should be arranged before test.

5.5.2Take a general check to running status of each heating surface of the boiler before test started, and then raise the load to required output and keep it running steadily for 2 hours. The test will last about 4 hours.

5.5.3Try to keep boiler load, steam temperature, steam pressure and air flow steady during test. The allowed fluctuation of each main parameter is as below:

Pressure at main steam outlet: rated pressure ±2%

Steam temperature of superheater keeps at: rated temperature ±5 Steam temperature of reheater keeps at: rated temperature ±5 Oxygen content in flue gas at economizer outlet: design value ±0.4%O2.

5.5.4No soot blowing and no any operation disturbing operating mode are allowed during

test.

5.5.5Shut off the steam heaters for warming primary and secondary air before test.

5.5.6Any important operation must be proceeded only after approved by supervisor of test leading group during test.

5.5.7Quality of fuel coal should be close to the quality of designed coal during test; fineness of pulverized coal at pulverizer outlet should meet the requirements.

5.6 Safety Precautions & Warnings

5.6.1All personnel for test entering the working site must obey the safety rules on site.

5.6.2Temporary scaffold or platform, fence must be built on the necessary site.

5.6.3Be well protected to avoid scald when installing and pulling out the flue gas analyzing gun and pay attention to not dropping the analyzing gun.

5.6.4Testing personnel should stick to his post and should inform the test supervisor immediately if any abnormality happens.

5.6.5The testing personnel must be well protected when sampling and analysis to pulverized

coal.

5.6.6If any danger happens to equipments and personnel during test, operator should pause the test and deal with the danger according to the operation codes.

5.6.7Be careful when using the instruments to avoid damage and losing.

5.6.8Keep floor clean without any pollutant on the working site. The tools for repair and maintenance should be put together to the designated area.

6 Required Testing Tools for Trial Running

Required main instruments and apparatus for test are as in below table:

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Note: This table is for reference only. Use correct instruments according to actual test requirements.

The above temporary test instruments will be provided by E. Energy.

7 Test Content and Quality Control

7.1 Measurement of Flue Gas Temperature

The K type thermocouples test grids to measure flue gas temperatures in the air preheater inlet and outlet ducts separately. The thermocouples are connected automatic survey recorder (FLUKE 2625A) via compensating conductor.

Record the temperature each 15 minutes.

7.2 Analysis of Flue Gas Ingredients

Calibrate and recalibrate the oxygen analyzer both before and after test with standard gas. The calibrated result is used for correcting the tested result.

Install flue gas sampling pipes according to dividing principle of uniform section inside economizer outlet and preheater outlet ducts. Connect the sampling probe to the tank mixed with flue gas via rubber tube. Flue gas sampling pump extracts mixed flue-gas sample through the mixed tank, and then send the sample into the analyzer (ROSEMOUNT NGA2000) to analyze NO and O2 content in flue gas.

CO2 content in flue gas is calculated according to ASME PTC 19.10 SECTION 6.04.1.11. Notice during test:

(1)Check the connection of sampling system often during test to avoid any leakage.

(2)Flue gas sampling should be kept continuous during the whole test.

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