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UDC 621.18.001.42 : 003.62
IS0
FOR STA N DA RDl Z AT1 O N
I NT ERN AT1 ON A L O RG A N IZATl ON
IS0 R ECO M M EN DATI O N
R 889
TEST CODE
FOR STATIONARY STEAM GENERATORS
OF THE POWER STATION TYPE
1 st EDITION
December 1968
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 889, Test code for stationary steam generators of the power station type, was
drawn up by Technical Committee ISOlTC 64, Methods of testing fuel-using equipment, the Secretariat of which is
held by the British Standards Institution (BSI).
Detailed work on this question by the Technical Committee led, in 1964, to the adoption of a Draft
L/ IS0 Recommendation.
In May 1966, this Draft IS0 Recommendation (No. 887) was circulated to all the IS0 Member Bodies for
enquiry. It was approved, subject to a few modifications of an editorial nature, by the following Member Bodies :
Argentina Hungary South Africa, Rep. of
Belgium India
Sweden
Brazil Israel Turkey
Chile Italy U.A.R.
Finland Japan United Kingdom
Germany New Zealand U.S.S.R.
Two Member Bodies opposed the approval of the Draft :
France
Ireland
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council, which decided,
in December 1968, to accept it as an IS0 RECOMMENDATION.
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CONTENTS
Page
1 .Scope . 5
2 . Definitions . 6
. .
3 Guiding principles 8 4
. .
4 Instruments and methods of measurement 13
5 . Testreport . 23
24
Table 1 . Symbols and Units (Methodical) .
Table 2 . Symbols and IJnits (Alphabetical) . 28
32
6 . Form of report to be used .
I General information and design data . 33
II Methodsofmeasurement andsampling andanalysisemployed . 39
III Mean observations and fuel data . 40
IV Computation of heat account . 50
..
V Thermal efficiency and heat account . 64
Annex A . Determination of quantity and enthalpy of combustion air . 68
Annex B . Determination of losses . 71
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ISO/R 889-1968 (E)
IS0 Recommendation R 889 December 1968
TEST CODE
FOR STATIONARY STEAM GENERATORS
OF THE POWER STATION TYPE
1. SCOPE
This IS0 Recommendation establishes the procedure for conducting acceptance tests on direct fired stationary
steam-generating units of the power station type, and presenting the test results in tabular form.
It provides for the determination of the heat output and of the thermal efficiency. The heat output should be
determined by direct measurements. The efficiency should be determined by one of the following methods :
- MerhodA : where possible, from the establishment of a complete heat balance, or
- Method B : where this is not possible, or where the expected accuracy of measurement of heat input
or heat output is unacceptable, by the determination of ail losses.
In either case the thermal efficiency may be expressed in terms of either the net or gross calorific value of the fuel.
The net thermal efficiency, based on the heat output reduced by the thermal equivalent of the power used by
auxiliaries, is not employed in this IS0 Recommendation. The power used by auxiliaries is to be separately recorded
in its appropriate units in the test report.
Provision is also made for the determination of the performance of the draught plant and pulverizers, and also for
the determination of steam purity, where such tests are required to demonstrate compliance with the provisions
of a contract.
The question of contractual tolerances is outside the scope of this IS0 Recommendation. The probable errors
involved in performing a test may be determined by combining the individual errors likely to arise from the separate
measurements by one of the established statistical procedures.
This IS0 Recommendation applies to large direct fired steam generators, primarily of the water tube type, which
may be equipped with
- superheaters,
- reheaters,
- economizers,
- recuperative air heaters,
- combustion and steam temperature control equipment.
The water circulation in the boilers may be by natural convection or by pump or by a combination of natural
convection and pump.
The steam generators may be fired by
- solid fuel,
- liquid fuel,
- gaseous fuel,
- a combination of any of these fuels.
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ISO/R 889-1968 (E)
2. DEFINITIONS
For the purpose of this code, the following definitions apply.
2.1 Stationary steam generating unit. A boiler with or without any or all of the following heat exchanging
components :
- superheaters,
- reheaters,
- economizers,
- air heaters,
and including
- plant for collection of grits or dusts for refiring in the furnace,
- combustion and steam temperature control equipment,
- ancillary plant or equipment which may be required for the proper operation of the unit, to an
agreed specification,
but excluding
- coal handling plant up to the outlet of the raw coal bunker,
- ash handling plant (except plant for return of ash to furnaces),
- plant for handling grits and dusts for external disposal,
- oil handling plant before the inlet to the oil heater,
- gas mains up to but excluding the main gas stop valve or isolating valve to the gas distribution mains
supplying the individual gas burners,
- feedwater heaters before the economizer,
- steam and feed mains except on the boiler side of the boiler isolating valves.
2.2 Heat output. The heat value of the steam supplied by the unit, less the heat values of any feed water and
steam returned to the unit.
2.3 Heat input. The heat value of the fuel used by the unit, based upon the net or gross calorific value as may
be required by the contract, plus any waste heat that may be supplied to the boiler from an external source
under the terms of the contract.
2.4 Thermal efficiency. The heat output less any heat (other than waste heat) supplied to the unit from a
separate thermal source other than that supplied in fuel or as mechanical or electrical energy divided by the
heat input.
2.5 Unit of calorific value. Calorific values should be expressed in terms of the jouie or its equivalent :
1 calIT = 4.1868 J
1 Btu = 1055.06 J
All calorific values should be those at constant pressure and corrected to one atmosphere standard pressure
= 1.01325 X lo6 dyn/cm*. The standard reference temperature for the calorific values of solid, liquid and
gaseous fuels shall be 25 OC.
2.6 Gross calorific value of a solid or liquid fuel at constant volume (e,,, .). The number of heat units measured
as being liberated per unit mass of fuel burned in oxygen in a bomb under standard conditions, the residual
materials being taken as gaseous oxygen, carbon dioxide, sulphur dioxide and nitrogen; liquid water in
equilibrium with its vapour and saturated with carbon dioxide; and ash. The gross calorific value as deter-
mined should be corrected to a standard reference temperature of 25 OC or its equivalent.
The value thus determined is sufficiently close to the calorific value at constant pressure (egr, ,,) to be
used without further correction.
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ISO/R 889-1968 (E)
). The gross calorific value as defined above, less the
2.7 Net calorific value of a solid or liquid fuel (Q
latent heat of evaporation at constant pressugk!the water both originally contained in the fuel and
formed by its combustion.
.
Net calorific value at constant pressure
- (52.5 H + 5.8 W)
in calories per gramme
Net calorific value at constant pressure
- (94.5 + W)
in British thermal units per pound
where
is the gross calorific value in cal/g of the fuel at constant pressure corrected to the reference
Qv. p
conditions of 25 "C and one standard atmosphere;
H is the percentage by mass of hydrogen in the fuel substance in the condition to which
Qgr, (or Qgr, p) refers and specifically excludes the hydrogen present in the moisture and
in the mineral matter associated with the fuel;
W
is the percentage of total moisture in the fuel substance in the condition to which Qgr, y
(or Qgr, p) refers and is the sum of the moisture in the fuel substance and the combined water
of the mineral matter.
Gross calorific value of a gaseous fuel at constant pressure (eA). The number of heat units measured as
2.8
being liberated when unit volume of the gas is burned at constant pressure in a flow calorimeter in excess
air at the same temperature and pressure; the gas being measured under standard conditions of temperature,
pressure and degree of saturation with water vapour, and the materials after combustion consisting of the
gases, carbon dioxide, sulphur dioxide, oxygen together with nitrogen and water vapour, equal in quantity
to the incoming gas and air, and liquid water equal to that produced during combustion, the pressures and
temperatures before and after combustion being equal.
The standard conditions of temperature, pressure and humidity for the purpose of measurement of the
volume of the gaseous fuel are 15 "C (60 OF), one standard atmosphere and complete saturation. The
reference conditions of temperature and pressure at which the calorific value of a gaseous fuel should be
stated are 25 "C and one standard atmosphere.
2.9 Net calorific value of a gas at constant pressure (Q,). The number of heat units released per unit volume of
gas when the gas is burned at constant pressure in air in a calorimeter of defined type under defined condi-
tions and the combustion products consist of carbon dioxide, water, (from the hydrogen and the hydro-
carbons) in the vapour state, oxides of sulphur, oxygen and nitrogen; the gas, the air used for its combustion
and the combustion products being at the same reference temperature.
Net calorific value of a gas
105.07
at constant pressure in
(d+-)
= QA-y 2
kilocalories per cubic meter
i
Net calorific value of a gas
1 1.807
at constant pressure in = 0.1 1237 QA - - (d+-)
V 2
British thermal units per cubic foot
where
is the gross calorific value of gas at constant pressure at the reference c nditions of 25 "C and
QA
one standard atmosphere,
V is the kilogramme molecular volume of the standard gas in cubic metres,
d is the percentage by volume of hydrogen in the gas,
e is the percentage by volume of hydrocarbons CxHY in the gas,
is the number of hydrogen atoms in C,H,,, the calculated mean formula of the hydrocarbons.
y
NOTE. - The terms and symbols employed are tabulated and described in Tables 1 and 2 of section 5.
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ISO/R 889-1968 (E)
3. GUIDING PRINCIPLES
3.1 Method of determining efficiency
A test according to Method A (see section 1) requires the direct determination of the heat output and
input as part of the establishment of the heat balance. In a test according to Method B, one of these
primary quantities is unmeasured and the efficiency is obtained by subtracting the various losses, expressed
as percentages, from 100 making due allowance for the effect of the heat input to the auxiliaries. Whether
the heat input is measured or not, it is still necessary to carry out sampling and analysis of the fuel and the
gases, as well as of the refuse. Special precautions should also be taken in relation to the determination of
the losses, and these precautions are mentioned in the appropriate clauses of section 4.
3.2 Preliminary observation of plant
Before any arrangements for acceptance tests are made, the plant should be observed in operation for as
long as may be necessary to confirm that the specified working conditions can reasonably be met.
Such working conditions are the following :
(a) Output
(1) from main boiler stop-valve,
(2) from reheater(s), if installed.
Pressure of steam
(1) at the superheater outlet,
at the inlet to the reheater(s),
(2)
at the outlet from the reheater(s).
(3)
Temperature of feed water entering the unit
(c)
(d) Temperature of steam
(1) at the superheater outlet,
at the inlet to the reheater(s),
(2)
at the outlet from the reheater(s).
(3)
(e) Temperature of air
(1) ambient air,
externally preheated combustion air (if applicable).
(2)
The working conditions should be attained at positions specified in the contract, or failing such specifi-
cations, at a point immediately adjacent to the component concerned.
It should also be verified that the appropriate fuel or fuels can be burned at the necessary rates, and it
should be established by flue-gas analysis that at these rates there are no significant losses due to unburnt
gases.
If such preliminary observation discloses that the specified working conditions, as listed above under
sub-headings (a) to (e) inclusive, cannot be met in any one or all particulars, or if the characteristics of
the available fuel are different from those specified, the test may be carried out, by agreement between
the parties, under the operating conditions shown to be feasible, and on agreement also on the resultant
changes in the guarantee values.
It is recommended that correction curves for deviations from the reference temperature of feed-water
temperature, temperature of steam at inlet to the reheater(s), externally pre-heated combustion air
and external air, as well as for deviations of steam throughput, should have received the prior agreement of
the parties and should preferably have been written into the contract.
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ISO/R 889-1968 (E)
3.3 Items on which agreement should be reached
The tests should be conducted by a competent experienced person who should be appointed by the parties
to the test.
The parties concerned should agree, before the tests, on the following matters :
1. The extent of the duties and responsibilities of the designated competent person.
2. The specific objects of the tests (see section 1).
3. That the specified working conditions can reasonably be met and that the appropriate fuel(s) can be
burned at the necessary rate(s) (see clause 3.2).
4. Correction curves or tables for deviation of test conditions from stipulated operating conditions
(see clause 3.2).
5. The number and duration of the tests (see clause 3.7).
6. That the specified fuel to be used in the tests is available in adequate quantity to meet the require-
ments of 3 above (see also clause 3.4).
7. In the event of a plurality of fuels being burned, the ratio of the different fuels to be used.
8. The method of evaluating the efficiency, i.e. either through the determination of a complete heat
balance by Method A or through an evaluation by Method B (see section 1 and clause 3.1).
9. The method of expressing the thermal efficiency, i.e. whether in terms of gross or net calorific value.
1 o. The general method of operating and responsibility for operating the plant during the tests.
11. If various manufacturers are involved, their respective responsibilities for the performance of the
component plant items and of the plant as a whole.
12.
The laboratory, or laboratories, of recognized standing to make the necessary analyses of fuel and
refuse.
13. The provision of reserve fuel samples (see clause 4.1 2).
14. Any departure from the methods of measurement prescribed by this code.
NOTE. - Such departures should be recorded in the Test Report.
15. The steam tables to be adopted.
16. The state of the plant, i.e. cleanliness of contact surfaces, wear and tightness, and the operation of
cleaning equipment (see clause 3.4).
17. The operation of blow-down and, if to be used, the method of measurement (see clause 3.4).
18. The operation of integral ash-quenching equipment (see clause 3.4).
19. The method of measurement of fuel (see clause 4.1 1).
20. The method of sampling fuel (see clause 4.12).
21. The method of fuel grindability determination (see clauses 4.12 and 4.22).
22. The method of obtaining masses of refuse (see clause 4.14).
23. The method of assessment of heat losses from water-filled ash hopper and from soli. residues of
combustion (see clause 4.16).
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ISO/R 889-1968 (E)
24. The method of sampling refuse (clause 4.15).
25. The method of flue gas analysis (see clause 4.7).
26. The method of measuring feed-water (see clause 4.8).
27. The instruments to be used for temperature measurement (see clause 4.5).
28. When testing according to Method B the value to be adopted, where necessary, for radiation and
convection loss (see clause 4.18).
29. The methods of steam purity measurements and correction, and of boiler-water conditioning (see
clause 4.23).
30. The location of instruments (see clause 4.3).
3 1. The measurement intervals (see clause 4.3).
32. The conditions under which a test should be terminated as unsatisfactory (see clause 3.8).
3.4 Preparation for test
Before an acceptance test, the plant should be placed at the disposal of the manufacturer for examination
in order to ascertain that it is in suitable condition, in particular that the steam generator is in the specified
state of cleanliness.
The furnace casing, gas and air conduits, and casings of the economizer and air heater should be tested for
leakage, and any abnormal leaks should be stopped before the test is started.
During the test, the cleaning equipment should not be operated except by prior agreement between the
parties concerned, in which case the fact should be recorded in the test report and the times and periods
of such operation should be stated.
During an acceptance test, the boiler should not be blown down nor should the integral ash-quenching
equipment be operated unless such operations are specifically agreed between the parties, or specified in
the contract as permissible during the test. In this event, the times and periods of operation should be
recorded in the test report.
The unit under test should be completely isolated from any supplies of feed-water or fuel other than those
passing through their respective measuring devices. Precautions should be taken to avoid all leakages of
water or steam, inwards or outwards, which will affect the results of the test. Similar precautions should
be taken with liquid or gaseous fuel. Wherever practicable unused pipes should be blanked off, otherwise
continuous supervision must be possible.
In preparation for any test the plant should be run for a sufficient time to attain a reasonable equilibrium
of temperature and combustion at test load conditions. Normally it is recommended that the plant should
have been in continuous operation for three days before the commencement of the test; of the last 12 hours,
9 hours should be at a minimum of three-quarters of the test load and the last 3 hours at the test load.
During these last 3 hours the following conditions should prevail :
the steam output should not vary more than * 3 from the test value;
(U)
the extreme values of steam pressure should not differ from one another by more than 6
(b)
the extreme values of difference between the temperatures of the gas at the unit exit and the
(c)
ambient air should not differ from one another by more than 6
During the whole of the preliminary running the unit should be fired with the fuel(s) agreed upon for the
test, unless otherwise agreed (see clause 3.1 and 3.2).
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ISO/R 889-1968 IE
3.5 Preliminary test
A preliminary test should be made for the purposes of
checking the operation of all instruments;
(a)
the training of observers and other test personnel;
(b)
establishing proper combustion conditions for the particular fuei(s) and rate(s) of burning to
(c)
be employed, and ensuring the absence of unburnt gases in the flue.
Normally the duration of the preliminary test need only be such as to fulfil these purposes but, should it
be established that all the requirements of a regular test are being met, the preliminary test may be
continued for the full duration of an acceptance test subject to the continued compliance with the require-
ments of this code and as specified in clause 3.7, and, with the agreement of the parties, may be recognized
retrospectively as a regular acceptance test.
3.6 Conditions at beginning and end of test
The foliowing values should show adequate greement at the beginning and end of the test
(U) combustion conditions;
(b) excess air;
(c) rate of feeding fuel;
(d) rate of feeding water;
(e) steam pressure;
U, water level in drum;
main steam and reheat steam flows.
(g)
With grate firing, and particularly when using Method A of efficiency determination, the stock of fuel on
the grate and its condition should be the same at the beginning and end of the test.
With mechanical grates, the average grate velocity and the height of the fuel layer, at least during the
period of one pass of the fuel on the grate, should be the same at the beginning and end of the test. These
values must, therefore, be observed for an adequate period before commencement and after termination
of the test.
In view of these requirements it is recommended that in cases where, in compliance with clause 3.7, a
test of long duration necessitates a change of observers during its course, the observers at the end of the
test should be the same as at the beginning.
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1
ISO/R 889-1968 (E
3.7 Duration of test
To meet the requirements of clause 3.6 the plant should be run under test conditions for not less than
I hour before and after the test period, or for such time as to collect sufficient data to establish that
similar and steady conditions prevailed at the beginning and end of the test. The final hour may be omitted
by agreement between the parties if pulverized fuel direct fired on the unit system, gaseous or liquid
fuel, is being used.
In fixing the duration of efficiency tests, the limiting factor with solid fuels is generally the time necessary
to reduce the variation in the quantity of fuel in the system at the beginning and end of the test to such
a small percentage of the total fuel consumption as not to influence appreciably the measured efficiency.
For plant which is fired by a travelling-grate or spreader stoker, a minimum period of 6 hours is recom-
mended.
With retort stoker firing there should be a preliminary period of 24 hours followed by the actual test
period of 24 hours minimum duration. A final control period of 12 hours should follow the actual test
period.
With pulverized fuel, directly fired on the unit system, or with oil fuel or gas firing, a period of 4 hours
in addition to the control period or periods is usually sufficient.
In the case of pulverized fuel not directly fired from the pulverizer, a longer period is usually necessary
for the correct determination of the fuel consumption. The duration can only be determined by an
examination of the plant and the possible variation of the quantity of fuel contained in the system
between the point of weighing the fuel and its delivery to the furnace. The test should be of sufficient
duration to reduce this variation of the quantity to a percentage of the total fuel consumed which is
consistent with the required degree of accuracy of measurement.
For boilers with slagfurnaces, under certain circumstances, the foregoing test periods may need to be
extended and the test duration must be the subject of agreement between the parties. having regard to the
foregoing considerations, the characteristics of the plant and the desired degree of accuracy.
When testing by Method B, 4 hours, in addition to the control periods, usually suffice.
Except in the case of tests of long duration, when the precaution noted in clause 3.6 should be observed, it
is not desirable to change observers during a test. It is recommended (see clause 4.3) that the intervals
between readings should be so chosen as to avoid unnecessary fatigue.
3.8 Rejection of test runs
A test may be either discontinued or rejected by either of the parties after completion for reasons which
must have been the subject of prior agreement and which may relate to certain eventualities, such as grave
contradictions in the observed data, substantial divergencies between the properties of the fuel used and
those originally laid down for the tests, etc.
In particular, the test may be discontinued or rejected if excessive variations occur of pressure or steam
output, or of steam temperature.
Such variations may be considered as “excessive” and may therefore involve the rejection of the test
unless otherwise provided for in the contract, if they are such as to disturb the equilibrium running
defined in clause 3.4 as having to be reached before the tests actually begin.
NOTES
1. Variations during the test, if they are of long duration, may involve the rejection of the test when they correspond
to deviations greater than those laid down as criteria in clause 3.4.
2. Momentary variations may exceed the limits specified in clause 3.4 without involving the rejection of the test,
providing the parties, taking into account the frequency, duration and time of occurrence of the variations, are
agreed that they are not such as to upset appreciably the equilibrium of temperature in the different parts of the
generator.
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ISO/R 889-1%8 (E)
4. INSTRUMENTS AND METHODS OF MEASUREMENT
4.1 General
Application of the requirements of section 1 involves the determination of all or part of the following
quantities :
(see clauses 4.8 to 4.1 O)
- Heat output
--- Heat input (see clauses 4.1 1 to 4.13)
- Losses due to refuse (see clauses 4.14 to 4.16)
(see clause 4.17)
- Losses due to flue gases
- Radiation and convection loss (see clause 4.1 8)
- Energy used by auxiliaries (see clause 4.19)
The object of this section is to provide rules for the correct execution of measurements relating to these
quantities.
4.2 Type and calibration of instruments
In this section are given alternative methods of measurement which can be employed and the parties to
the tests must agree upon the methods to be adopted. Any departure from these methods, or the use
of any instruments not covered by this code, should also be the subject of prior agreement and any such
deviations from the prescribed procedure shall be fully described and recorded in the test report.
Recording or integrating devices should be used only by express agreement between the parties and provided
that their use will not lead to the loss of accuracy. Calibrations should be carried out before the tests of all
instruments and apparatus which are vital to the objects of the tests. In some cases it may be considered
necessary to repeat calibrations after the tests.
4.3 Location of instruments and periodicity of readings
The location of all instruments should be agreed upon by the parties prior to the commencement of the
test. Where possible at no sacrifice of accuracy, the use of remote indicating instruments is recommended,
and the location and grouping of all instruments, whether local or remote reading, should be considered
from the standpoint of the observers, with the object of ensuring accurate measurements with the minimum
of fatigue, having due regard to the agreed duration of the tests.
All readings should be taken at such frequency as may be necessary to determine the true average. Except
for quantity measurements, the interval between readings should normally be 10 to 15 minutes provided
that there should be not less than twenty-five uniformly spaced readings. If, however, there are sudden
and wide fluctuations, it may be necessary to reduce this interval. In the case of flow measurements using
indicating instruments, half minute intervals are recommended, unless otherwise agreed.
It should be noted that too short intervals can result in an increase in the error due to fatigue of the
observers taking the readings.
As far as possible the initial and final readings of all quantitative measurements should be taken simulta-
neously. The steady-state values are best read off a short time before the beginning of the test period. It
is recommended that all readings should be continued throughout both the initial and final control periods.
4.4 Recording of data
The observed data should be directly recorded by each observer on log sheets designed for the purpose,
which log sheets should include the reference number of all instruments. It is recommended that these
data should be transferred to a single master log sheet.
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ISO/R 889-1968 (E)
4.5 Temperature measurement
4.5.1 The following types of thermometer may be used for temperature measurement :
Mercury-in-glass solid stem thermometers with scales suitable for the measurement to be made
(a)
in
...