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Demonstrate knowledge of steam generation water treatment in a
thermal power station
Level
4
Credits
6
Purpose
People credited with this standard are able to demonstrate knowledge of:
impurities contained in water sourced for steam generator feedwater
applications; processes utilised to neutralise or remove potential feedwater
impurities; steam generator water quality monitoring methods and associated
equipment; and the effects of steam and water cycle chemical parameter
excursions.
Subfield
Electricity Supply
Domain
Electricity Supply - Thermal Operations and Control
Status
Registered
Status date
20 June 2006
Date version published
20 June 2006
Planned review date
31 December 2011
Entry information
Open.
Accreditation
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
Electricity Supply Industry Training Organisation
Accreditation and Moderation Action Plan (AMAP) reference
0120
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Special notes
1
This unit standard is intended for, but not restricted to, workplace assessment. The
range statements within the unit standard can be applied according to industry
specific equipment, procedures, and processes.
2
Safety of personnel and plant must be a priority throughout the assessment. If the
safety requirements are not met the assessment must stop and the candidate will be
assessed as not yet competent.
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3
Performance and work practices in relation to the elements and performance criteria
must comply with all current legislation, especially the Electricity Act 1992, and any
regulations and codes of practice recognised under that statute; the Health and
Safety in Employment Act 1992; and the Resource Management Act 1991.
Electricity supply industry codes of practice and documented industry procedures
include the Safety Manual – Electricity Industry (SM-EI) (2004) Wellington: Electricity
Engineers’ Association. A full list of current legislation and industry codes is
available from the Electricity Supply Industry Training Organisation, PO Box 1245,
Hamilton.
4
‘Industry requirements’ include all industry and workplace documented policies,
procedures, specifications, business, and quality management requirements relevant
to the workplace in which assessment is carried out.
5
‘Steam generation’ is a collective term for boilers and heat recovery steam
generators utilised in thermal (including combined cycle and co-generation) power
stations.
Elements and performance criteria
Element 1
Demonstrate knowledge of impurities contained in water sourced for steam generator
feedwater applications.
Performance criteria
1.1
Common suspended solid concentrations are identified and their effects on
feedwater and steam generator equipment are explained.
Range
1.2
Common dissolved gas concentrations are identified and their effects on
feedwater and steam generator equipment are explained.
Range
1.3
includes but is not limited to – blockages, erosion, abrasion.
includes but is not limited to – oxidation, pitting corrosion,
grooving, acid and caustic embrittlement.
The concentrations of common dissolved solids are identified and their effects
on feedwater and steam and water cycle equipment and operation are
explained.
Range
includes but is not limited to – carryover, impurity deposition,
scale, accelerated corrosion.
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Element 2
Demonstrate knowledge of processes utilised to neutralise or remove potential feedwater
impurities.
Performance criteria
2.1
Feedwater pre-treatment methods are explained in terms of purpose and
operation.
Range
2.2
Deairation processes are explained in terms of purpose and operation.
Range
2.3
includes but is not limited to – ion exchange, reverse osmosis,
evaporation, blowdown.
Chemical dosing regimes complementing water treatment processes are
explained in terms of purpose and operation.
Range
2.5
includes but is not limited to – mechanical and chemical methods.
Dissolved solid removal processes are explained in terms of purpose and
operation.
Range
2.4
includes but is not limited to – disinfection, screening, filtration,
clarification, coagulation, flocculation, settling.
may include but is not limited to – all volatile treatment,
oxygenated treatment, oxidizing all volatile treatment, caustic
treatment, phosphate based chemical dosing, specialist
conditioning chemical dosing.
Factors determining specific water treatment process utilisation are explained.
Range
includes but is not limited to – steam generator and feedsystem
design and materials, boiler operating pressure and temperature
ratings, steam quality requirements and applications, steam
generator operational requirements, cost.
Element 3
Demonstrate knowledge of steam generator water quality monitoring methods and
associated equipment.
Performance criteria
3.1
Methods of monitoring steam generator steam and water cycle chemistry
conditions are described in accordance with industry requirements.
Range
includes but is not limited to – manual sampling, sample analysis,
on-line monitoring equipment.
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3.2
Function and operation of instruments and equipment used to monitor boiler
water quality are described, and associated units identified.
Range
may include but is not limited to – conductivity meter, resistivity
meter, cation conductivity, pH meter, silica analyser, dissolved
oxygen meter, turbidity meter, sodium analyser.
Element 4
Demonstrate knowledge of the effects of steam and water cycle chemical parameter
excursions.
Performance criteria
4.1
Effects of steam generator operation outside of chemical parameters are
described.
Range
4.2
Feedwater contamination prevention methods are described in accordance with
industry requirements.
Range
4.3
may include but is not limited to – priming, foaming, carryover,
caustic embrittlement, flow accelerated corrosion, pitting corrosion,
corrosion fatigue, acid phosphate corrosion, grooving, hideout,
scale, impurity deposition.
may include but is not limited to – condensate polisher,
condensate and feedwater monitoring, diversion system.
Major chemical parameter excursion response procedures are outlined in
accordance with industry requirements.
Range
may include but is not limited to – contamination source detection,
drain provisions, blowdown and make up, condensate and
feedwater dumping, emergency dosing, deloading, shutdown.
Please note
Providers must be accredited by the Qualifications Authority, or an inter-institutional body
with delegated authority for quality assurance, before they can report credits from
assessment against unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by the Qualifications Authority before
they can register credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
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Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Electricity Supply Industry Training Organisation info@attto.org.nz if
you wish to suggest changes to the content of this unit standard.
 New Zealand Qualifications Authority 2016