1 Technical Code Designing Fossil Fuel Power Plants
1.1 Foreword
This code is a professional standard containing compulsory articles, and those articles
are compulsory. Compulsory content in tables is indicated by notes for the table.
Since the issuance and implementation,DL5000 — 1994“Technical code for designing
fossil fuel power plants” has played a positive role and achieved good effects in carrying out
the capital construction policies of the state, reflecting the economic and technical policies,
unifying and defining construction standards, ensuring adoption of advanced technology in
the newly built and expanded fossil fuel power plants, realizing safe, economic, full load and
steady operation and satisfying the environmental protection requirements in the construction
of electric power facilities.
With the deepening of reform and advance of technology, some aspects of DL5000 —
1994 can no longer meet the requirements in the development of construction of electric
power facilities. According to the arrangement in Item 42 of the document NO.[1999]
40“Notice on confirming standard system and revision plan item in electric power industry in
1998”of the Department of Electric Power of the State Economic and Trade Commission, the
Electric Power Planning and Design General Institute organized people to conduct the
revision and compilation of DL5000—1994.
In this revision and compilation, the basic policies on electric power construction have
been carried out, the policy on “safe and reliable, economic and complying with national
conditions” and a series of measure to control project cost conscientiously implemented, and
mature and reliable design technology adopting advanced techniques actively popularized,
with due consideration given to saving coal, water, power and land and controlling the size
and standard of non-production facilities. Attention has been paid to adapting to the socialist
market economic system, to get well prepared in design and technology for the electric power
construction in the 21st century.
In this revision and compilation, no major revision has been made to the framework of
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DL5000—1994, only some revision, deletion and supplement have been made to the contents
of relevant section, and some sections have been adjusted as appropriate.
To spreading and application of gas-steam combined recycling power generation
technology, flue gas desulfurization technology and clean coal power generation technology
are the development orientation of the power industry in the 21st century, however, compared
with the conventional coal-firing power generation technology, they are not so mature as
there is not much practical experience in the country. Therefore, in this revision and
compilation, only some fairly mature articles were prepared for perspective.
This code was proposed by the State Electric Power Corporation.
This code shall be under the charge by China Electric Power Planning and Design
Association.
This code shall be interpreted by China Electric Power Planning and Design
Association.
1.2 Scope
This code has specified the principles that should be followed and the construction
standards in the design of large sized fossil fuel power plants. This code is applicable to the
design of condensing type fossil fuel power plants with units of turbo-generator sets at
capacity of 125MW—600MW,as well as fossil fuel power plants with heat supplying units at
or above 50MW.It can be used as reference for units of and above 600MW.This code is
applicable to the design of newly built or extension of power plants, and can be used as
reference for the design of modification projects.
1.3 General Provisions
The unit capacity of power plants shall be selected in accordance with such factors as the
system planning capacity, load increase rate and grid configuration. Large capacity unit with
high efficiency shall be selected, provided that maximum unit capacity should not exceed
10% of the total system capacity.
There should be no more than six units in a power plant, with no more than capacity
grades for the units. Turbo-generators and boilers of the same capacity should be of same
type or modified type, and with the same types of associated equipment. A newly built power
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plant should be built in one or two phases to the planned capacity on the basis of load demand
and available capital high-efficiency unit of the same type, and be constructed successively.
In power plant design, overall coordination shall be made and technical requirements
shall be raised on the main auxiliary equipment and systems required, and selection shall be
made among the same type of equipment on the basis of technical performance, reliability,
supply conditions, prices and performance and technical service quality of manufactures.
When conditions are standard series products and energy-saving products shall be selected in
priority.
1.4 Site Selection
In site selection for power plants, the following condition shall be studied: grid
configuration, power and heat load, fuel supply, water source, traffic, transport of fuel and
large equipment, environmental protection requirements, disposal of fly ash and slag,
outgoing line corridor, geology, seismology, topography, hydrology, meteorology, land
requisition and relocation, construction, and influence of surrounding industrial and mining
enterprise on the power plants, so that preliminary schemes can be drawn up and justification
and evaluation can be made through overall technical and economic comparison and
economic efficiency analysis.
In the site selection for planning, comments shall be made on the construction scale and
completion time, with proposal on the number and capacity of units to be installed.
In the site selection for engineering, comments shall be made on the construction scale
and completion time, with proposal on the number and capacity of units to be installed.
In selecting power plant sites, full consideration shall be given to the outgoing
conditions for connection with the grid when the power plants reach the planned capacity.
1.5 Arrangement of Main Building
The main buildings should be arranged in the order of boiler house, coal bunker bay,
deaerator bay (or combined coal bunker and deaerator bay) and turbine, and their size should
not exceed those of the reference design for main buildings for units of the same category.
When it is deemed reasonable after technical and economic justification and according to the
actual project conditions, other new forms of arrangement that can control project cost and
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favorable to operation, maintenance and construction can also be adopted. The comparable
building volume of main building shall not exceed data of reference design of main buildings
for units of the same category.
In non-severely cold regions, boilers should be in open or semi-open arrangement. In
areas with severe cold or strong sandstorm, tower type boilers should be tightly enclosed with
outer wall boards, and non-tower type boilers shall either be tightly enclose with outer wall
boards or be arranged indoor according to the equipment features and actual condition of the
project. In regions with proper climate conditions, boilers with good sealing can be arranged
without top compartment and rain shield.
1.6 Boiler Equipment and Systems
The type selection of boiler equipment and technical requirements shall be as specified
in “Technical Specification for Coal Fired Power Plant Boiler” SD268-1988. The type of the
boiler equipment must be suited to the quality characteristics of the coal used and the
allowable variation of the coal quality in the current specifications. The physical and
chemical tests and analyses of the coal and its ash shall be performed to obtain the normal
and abnormal characteristic data of the coal quality.
The pressure drop from the superheater outlet of the large capacity boiler to the turbine
inlet shall be 5% of the rated inlet steam pressure of the turbine. For the unit with subcritical
and below parameters, the rated steam temperature at the superheater outlet shall be 3℃
higher than the rated inlet steam temperature of the turbine. At rated conditions, the pressure
drops of the cold reheat steam piping, reheater and hot reheat steam piping shall be
1.5%~2.0%. 5%, 3.5%~3.0% respectively, of the HP turbine exhaust steam pressure at the
operation conditions. The rated steam temperature at the reheater outlet shall be 2℃ higher
than the rated inlet steam temperature of the IP turbine.
The design of the pulverizing system for boiler combustion and equipment shall be in
accordance with the design of the boiler proper and its safety protection monitoring system
and shall conform with the specifications is “Anti-explosive Directories of Pulverized Coal
Boiler Combustion Chamber of Fossil fuel power plant” DL345.
