AnthraciteFiring_LargestSteamGenerators

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Anthracite Firing – Largest SteamGenerators

P. Brower/J. Winkin Foster Wheeler Energy International, Inc.

Ge ChangqinHebei Electric Power Corporation





Anthracite Firing – Largest Steam Generators

P. Brower/J. Winkin, Foster Wheeler Energy International Inc., U.S.A.

Ge Changqin, Hebei Electric Power Corporation

Summary:

The size and scope of the Hanfeng Power Plant is a large undertaking by any definition. It is progressing

very well with good coordination and cooperation of all those involved. Start-up is scheduled for the first unit

in the year 2000 with the second unit following by eight months.

The boiler island scope covers all equipment and structural steel from the bunkers to the stack. This

includes the two (2) world’s largest anthracite fired boilers burning a blend of very low volatile Chinese

anthracite and lean coal (bituminous). The coal blending is designed to maximize the use of the local

anthracite coal. This is done by controlled blending at the entrance to the large FW D12D ball mills.

Scaling up from earlier extensive experience with arch fired boilers is reviewed as well as key features of the

Hanfeng boilers each of which are capable of generating 563 kg/s of steam at 540.8°C and 175 bar

(equivalent to 717 MW of turbine/generator output).

The design of the boiler and related equipment for the Hanfeng project has been the subject of in-depth

reviews by independent engineers representing the banks to assure reliability of the boiler to support the

economic model. It has been shown that FW’s extensive experience burning anthracite coals has justified

the scaling up of the various components to meet the requirements of the specification. This experience is

based on operating similar type anthracite arch fired boilers with fuel blends that are comparable to the coals

to be supplied for the Hanfeng project.

The materials and equipment for the Hanfeng boiler island are being supplied on a multi-national basis in

support of the various requirements of the financing institutions involved. The overall design has been

finalized and the detail design is well underway. Most of the large critical components are already in

manufacturing.



Hanfeng Project – Boiler Island:

China, an extensive country with a land area about 2% more than the United States and the world’s largest

population, presently has the world’s largest growth of installed electrical utility power generation ordering

over 22,000 MWe in1996. A significant resource in meeting its related fuel supply needs, both at present and

for future generating units, is China’s very large reserves of anthracite coal. So it is expected that China

would have a need for generating large quantities of power from this abundant resource, eventually using the

largest sized units available. This in fact is what is now happening. The entity that is carrying out this

advancement in power generation is the Hebei Hanfeng Power Generation Co. Ltd. (HPGCL). It is a joint

venture company comprised of Hebei Electric Power Corporation (the operating power company in the

province where it will be located), Hebei Construction and Investment Corporation, North China Power Group

Company and Siemens Power Development Hanfeng GmbH (a subsidiary of Siemens AG).

The project is the Hanfeng Power Plant (HPP) which is being built near Handan City in China’s Hebei

Province, about 400 km southwest of Beijing. The nominal rating for Phase I of the Hanfeng plant is 2 x 660

MW. HPGCL has arranged with Hebei Electric Power Corporation (HEPC) to be the responsible party for

construction of HPP and for the operation and maintenance of the completed plant. HEPC in turn has

evaluated available technologies, following which it selected and contracted with Foster Wheeler Energy

Corporation (FWEC) to supply the anthracite fired boilers under a consortium arrangement for the plant

power block including turbine/generator, I&C and electrical islands by Siemens AG of Germany.

HPP will have two natural circulation balanced draft, arch fired (down-shot) boilers each of which will supply a

maximum of 563 Kg/s (4,468,300 lbs. per hr.) of steam at 540.8°C (1005°F) and 175 bar (2538 psig)

pressure with single reheat at 540.8°C to a steam turbine/generator with a maximum valves wide open

capacity of 717 MW.

The units are designed to operate in base load or load following mode under either hybrid variable pressure

or constant pressure conditions. The system design has been based on relatively fast start-up and load

rejection times utilizing a 40%HP/30%LP turbine by-pass system, fast actuators and 20% boiler electromatic

relief valve capacity.

FWEC’s scope of supply for the boiler island includes all equipment from the coal conveyor discharge at the

bunkers to an interface at the stack breeching. This includes the following major systems and equipment

which are arranged as shown on Fig. 1:

A. Coal Feed and Firing System

1) Coal Bunkers with stainless steel lined hoppers and stainless discharge piping

2) Four (4) Gravimetric Coal Feeders per Pulverizer

3) Six (6) FW D12D Ball Mill Coal Pulverizers

4) Two (2) Centrifugal Primary Air Fans

5) Coal Piping from each Pulverizer to Six (6) Burners

6) FW’s proven Anthracite Double Cyclone Burners – 36 per unit

7) Oil Ignitors/warm-up guns

B. Secondary Air/Flue Gas System

1) Two (2) Axial Forced Draft Fans with variable pitch blades



ENCLOSEDCOAL

BUNKERBAY

STEAMGENERATOR

HANFENG BOILER ISLAND

(24)FEEDERS

(6)D12D

BALL MILLS

BOTTOMASHSCRAPER

(2)CENTRIFUGAL

PA FANS

(2)AXIAL

FD FANS

(2)AXIAL

ID FANS

(2)ELECTROSTATICPRECIPITATORS

FIGURE -1

TRI-SECTORAIR

HEATER

HANFENG10

2) Complete Flue and Duct System with Dampers

3) Windbox with Air Damper Control

4) Two (2) Regenerative Trisector Air Heaters

5) Two (2) four field double chamber Electrostatic Precipitators

6) Two (2) Axial Induced Draft Fans with coated steel blades

C. Steam Generator Units

1) Boiler including Economizer, Refractory lined Lower Furnace Waterwalls, Steam Drum and

Downcomers with Lower Header Pre Start-Up Heating2) Superheater comprised of Roof and heat recovery Area Panels, Rear Pass Primary Coils,

Furnace Partial Division Walls, and Pendant Finishing Superheater Coils

3) Single Reheater located in Inboard Pass of Heat Recovery Area with vertical loop exit

D. Auxiliary Systems

1) Furnace Bottom Ash Submerged Chain Conveyor

2) Piping Systems for Superheater Spray Attemperation, Auxiliary Steam, Service and Cooling

Water, Service and Instrument Air, Steam and Water Sampling, among others

3) Field Instruments, Electrical Cable Tray/Conduit, Lighting, Small Power

E. Steel Work

1) Enclosed Bunker Bay Steel Structure and Platforms

2) Outdoor Boiler Steel Structure with Roof Canopy and Platforms

Supply of the Turbine Island, Generator and Electrical Systems as well as a Plant Distributed control System

(DCS), Dry Ash Conveying, and certain other equipment are by Siemens AG, consortium partner with FWEC.

The DCS is of Siemens Teleperm design and incorporates FW’s burner management and combustion

control requirements.



Balance of plant supply is being provided by HEPC through contracting with various local suppliers. HEPC is

also responsible for contracts with local construction companies for the erection and testing of the power

plant.

The boilers are intended to burn large quantities of an abundant local coal (Wannian Anthracite) mined in the

plant’s district. This fuel’s volatile content is so low that it will be supported by blending with another coal

(lean mixed coal from nearby Shanxi Province) with higher volatile content. The range of key coal

parameters are presented in Table 1. These coals are sufficiently low in sulfur such that flue gas

desulphurization equipment is not required.

TABLE 1

HANFENG DESIGN COALS

Proximate Analysis

COAL ANALYSIS ON A AS RECEIVED BASIS

VM Dry

Ash Free VM Ash H2O HHV LHV

% % % % KJ/KG KJ/KG

Lean Coal 21.73 15.27 22.22 7.50 22863 21970

Wannian 5.25 3.90 20.14 5.60 25427 25078

50/50 Blend Average 13.26 9.58 21.18 6.55 24143 23526

80/20 Blend 8.40 6.17 20.56 5.98 24908 24450

Chinese light diesel oil is used for unit start-up and boiler warm-up.

Comparison of Boiler Capacity

The Hanfeng boilers will be the world’s largest anthracite fired boilers when started up. This can be seen by

referring to Fig. 2 which is a plot of the size of Foster Wheeler’s utility anthracite class fired boilers related in

MW output of the turbine versus the year of initial operation. Foster Wheeler is the industry leader in both the

size and number of boilers sold for anthracite class coals in Europe and the USA and now in China. While a

number of designs by domestic Chinese suppliers have been in use for many years, and some designs by

other foreign exporters have been introduced over the last decade in China, FWEC currently has twelve (12)

units in various stages of being built and many others being supplied by its Chinese licensee.

The two Hanfeng boilers which were sold in 1996 are at the top of the chart on Fig. 2 followed by the 3 x 500

MW boilers at Aberthaw B in Wales (United Kingdom). These are followed by a number of boilers in Spain

and in China which are in the 325 to 385 MW range.

The first boiler/turbine generator unit for the Hanfeng project is scheduled to go into operation by the end of

the year 2000. The second unit is scheduled for operation about 8 months later.

Comparison of Boiler Size

It is interesting to note that the physical sizes listed on Table 2 for the anthracite fired Hanfeng boilers shown

on Fig. 3 are about the same physical sizes as the largest boilers in the USA which fire bituminous coal and

which supply the steam requirements for 1300 MW size turbine/generators. They are both the same width.

The Hanfeng boilers have a deeper lower furnace, due to the arch firing of the anthracite coal, and a greater

height.



The fact that the furnace on an anthracite

fired boiler has to be so large in

comparison with bituminous firing while

only having about 55% of the capacity is

mainly due to the longer residence time

required for burnout of the slower burning

anthracite fuel. It also relates to the

anthracite for the Hanfeng project having

about two times the amount of ash than

is present in the U.S. bituminous coal

fired in the units from the above

comparison.

Hanfeng Fuel Blending

The Hanfeng boilers will burn a very low volatile local Wannian anthracite which will be blended in with an

equal or smaller amount of bituminous coal (Chinese lean coal) depending upon the load requirements. The

blending system is designed to maximize the use of the local anthracite coal. To do this, an arrangement will

be used to blend the anthracite and bituminous coals at the entrance to the mills as shown on Fig. 4 and Fig.

5. This same arrangement has been used for many years at the Vellia Unit 2 and the Compostilla II Unit No.

1 in Spain. The key feature of this coal blending system is to measure and control the desired mixture in the

blend by use of gravimetric feeders so that the proper proportions of each of the coals being blended is

obtained. Accordingly, it is then possible to control the burning of greater amounts of the low volatile

anthracite coal as the load on the boiler increases. This is because the furnace is hotter at higher loads, thus

TABLE 2

HANFENG BOILER SIZE

FURNACE:

Width – 34.48m

Depth (Including Windbox) – 15.54m

Height (Lower Header to Furnace Roof) – 52.1m

HEAT RECOVER AREA (HRA) – 2 Pass:

Reheater Depth – 4.53m

Primary Superheater Depth – 5.18m



HANFENG STEAM GENERATORS4,468,300 LBS/HR (563KGS)

2538 PSIG (175 BARS)

1000 F/1000 F (540.8 C/540.8 C)oo o o

FINISHINGSUPERHEATER

PRIMARY

SUPERHEATER

(36) DUAL CYCLONEBURNERS

ECONOMIZER

REHEATER

FIGURE - 3

STEAM DRUM

UPPERPARTIALDIVISIONWALLS

HANFENG11

improving the carbon burnout capability as well as the stability of the combustion process.

Coal Mills

The large quantity of low grindability coal for the Hanfeng boilers, in addition to the moderate heating value of

the blend coal required the use of six large

size FW D12D pressurized ball mills per

boiler. These mills are ideally suited to the

grinding of this low grindability coal mixture.

They also are fully capable of producing

desired high fineness levels, of 90% or

greater through 200 USS mesh, thus

enhancing the combustion process. The

ball mill is also very reliable and offers high

availability. The Hanfeng plant is being

designed conservatively to permit full load

operation even if one mill is out of service.

All of Foster Wheeler anthracite fired

boilers have used the same basic design of

ball mill as shown on Fig. 6. This is a

proven mill with 766 sold to date. Most

have been in service for many years with

an excellent record of reliability and

availability. Since 1994 Foster Wheeler

has sold 104 ball mills in China. All of these are for utility applications and in large capacity sizes for units

firing both anthracite and bituminous coals.



The Hanfeng boilers uses a direct firing system where the pulverized coal from the classifier at the exit from

the six mills is sent directly through 3-way splitters and coal conduits to the entrance of each of the 36 dual-

cyclone burners. It is then sent through a riffle divider box into two cyclone type burners. Each cyclone

burner vent discharges the transport air into the furnace, leaving an enriched mixture of air and coal to

discharge into the furnace through the burner nozzle at the bottom of each cyclone. There are two burner

nozzles for each dual cyclone burner assembly making a total of 72 burner nozzles (36 burner nozzles per

arch).

The Lower Furnace

Fig. 7 is an illustration of the lower furnace of the Hanfeng arch fired boiler. It shows how the secondary air is

introduced through both the front and rear walls to support combustion of the pulverized coal that is injected

into the lower furnace through the cyclone burners which are located in the arch. The flame from the burners

penetrates into the hopper and then turns upward giving it a “W” shaped pattern. This “W” shape of the

flame provides additional residence time that is required at the higher temperatures to burn the low volatile

coals that are characteristics of anthracite.



The “burning” takes place in two stages. In the

first stage, the volatiles are mostly burned off. In

the second stage, the burning of the char is

carried out. This is a time consuming process

and the lower the volatile matter of the coal the

longer it takes. The residence time required for

the burning of the char can be simulated and

measured in a drop tube furnace. Such

measurements comparing the residence time

required for burning to about the same unburned

carbon level are shown on Fig. 8 for a Spanish

coal (Anllares 350 MW) and a Chinese coal

(Hanfeng 80/20 blend). For a two second

residence time (equivalent to about a 350 MW

size boiler) they have about the same unburned

carbon levels. This indicates that the carbonburn up of the char will be about the same for the

two coals compared on Fig. 8. At over three

second residence time, found in larger capacity

boilers in the 600 MW size range, the unburned carbon is expected to be lower, as shown on Fig. 8.

Flame Stability and Turndown

The need for blending of the

Wannian coal (which is a local

anthracite coal) with bituminous

coal (Chinese lean coal) was

primarily dictated by the need for

flame stability and good

turndown capability which has

been specified as 40% of boiler

MCR. However, the final

confirmation of the need for

blending came from tests

conducted by Foster Wheeler,

which gave a high ReactivityIndex temperature. When this

was compared to Foster

Wheeler’s large database of

Reactivity Index testing, it was

very apparent that blending was

required with a coal having a

relatively low Reactivity Index temperature to obtain a turndown to the 40% load requirement by the



specification. It is Foster Wheeler’s experience, particularly in the low volatile matter range, that volatile

matter alone will not always give an accurate prediction of the ignitability (flame stability and turndown). It is

for this reason that the Reactivity Index test was developed. It has proven to be very reliable.

Scaling up to 717 MW

Fig. 2 showed that over the past 70 years FW has continued to developed larger size anthracite fired arch

type boilers. This has been an evolutionary process as is the scale up from the 350 - 500 MW sizes to the

717 MW size for the Hanfeng boilers. In this process, those features which have worked so well and have

given FWEC boilers high reliability and availability were maintained. For instance, FWEC has maintained a

design standard which produces a recirculation of hot gases in the furnace back to the area where fuel enters

the furnace, as show by a component simulation per Fig. 9. This hot gas recirculation enhances the ability of

FW arch fired boilers to burn low volatile coals.

The proven components of design such as the burners and the arrangement of the lower furnace are

incrementally larger. However, most of the increase in capacity was obtained by making the Hanfeng boilers

wider, resulting in more burner nozzles up to a quantity of (72) plus more and larger ball mills, six (6) D12D

size. The width of 34.3m is the same as has been used on ten (10) -1300 MW size boilers which have been

in operation in the USA for many years. Therefore, components such as long sootblowers have a solid

history of good operation.

In this scale up FW has maintained the limits of heat release rates and temperatures that have been proven

to be successful by FW on the largest data base that exists on the firing of anthracite using arch fired boilers.

This data base includes 25 boilers over 100 MW in size which are in operation.

Project Execution

The Hanfeng Power Plant project evolved through Chinese-German cooperation in a joint venture to develop

the project and provide its financing. This was a lengthy but successful process despite the complex project

financing arrangements and extensive reviews and approvals by the parties and the respective authorities, all

of which are inherently a part of such projects. Proposals were made from February 1994 through May 1996

in order to achieve the technical and financial goals of the project. There were in-depth reviews through the

Bank’s independent engineer to assure that reliability of the boiler design and other systems would be

supportive of the economic model. The contract for the boiler supply was signed on November 8, 1996 in the

Great Hall of the People in Beijing with Chinese Vice Premier Zou Jiahua in attendance thus underscoring the

project’s importance. Release to proceed came in June 1997.

At present the boiler supply for Unit 1 is in full swing. Most of the large critical components are already in

manufacture and some are in the process of being delivered to the site. The plant’s first unit will be on-line in

the year 2000 with an eight-month lag for Unit 2's operation.



FWEC is doing project management

and engineering from its USA office.

Extensive world sourcing is involved

on this project to support the various

requirements of financing institutions

involved. An integral part of this is

Foster Wheeler Energia S.A., Foster

Wheeler’s Spanish engineering and

manufacturing operation.

FW’s shops in Spain and China are

both providing pressure parts as are

several local Chinese fabricators.

Major auxiliaries are coming from

Spain, the United States and other

European countries. FWEC’s partner

Siemens AG is providing boiler island

electrical cables and trays plus lighting

and small power. Materials for

FWEC’s US designed steel are

coming from Japan for local fabrication

in China. The capabilities of China’s

manufacturing shops are growing.

Some very large components (including the 30.7m long steam drum, 4.4m diameter D12D mills and 7.2m

high welded girders to hold up the boiler) are being supplied from local Chinese companies.

Conclusion

The mines in the area of the Hanfeng Power Plant will begin an era of greater utilization as each successive

unit and later phases come on line. The added electrical power will spur further growth in Southern Hebei

Province. These factors will be very beneficial to Hebei Province and the joint venture owners should be able

to achieve a good return on their investments.



Speaker : P. H. Brower

Company : Foster Wheeler Energy International, Inc.

Country : U.S.A.

Philip Brower is the Proposal Manager responsible for FWEC’s Hanfeng Boiler Island Contract.

• His initial experience was in nuclear power with both Curtiss-Wright Nuclear and Foster Wheeler’s

Nuclear Department, serving in key engineering, manufacturing and project positions.

• He has been on FWEC’s Utility Boiler proposal team for 18 years, managing technical and commercial

aspects for fossil fuel fired boilers and related equipment on U.S. and international projects.

• Mr. Brower is a graduate of Stevens Institute of Technology at the Master’s level in Mechanical

Engineering and Management Science. He is co-author of a 1983 paper on Heat Pipe Air Heaters.

Speaker : J. P. Winkin

Company : Foster Wheeler Energy International, Inc.

Country : U.S.A.

Justin Winkin is a Consultant within Foster Wheeler.

• His initial experience with utility boilers was with Babcock & Wilcox, U.S.A. as a Service Engineer and a

Staff Engineer. He then was in charge of construction and operations for a subsidiary of General Public

Utilities, Corp.

• He returned to the boiler business by joining Foster Wheeler where he has had major responsibility in

Engineering, Manufacturing and Upper Management.

• He is a graduate of Rensselaer Polytechnic Institute in Mechanical Engineering and New York University

in Management. He is a Fellow of the American Society of Mechanical Engineers.

Speaker : Ge Changqin

Company : Hebei Electric Power Corporation (HEPC)

Country : P.R.C.

Ge Changqin is the Chief Engineer of HEPC’s Hanfeng Power Plant Preparation Department.

• His initial experience was with Hebei Electric Power Testing and Research Institute as a boiler engineer

and specialist in boiler combustion and heat transfer.

• Mr. Ge’s formal background is at the Master’s level in Boiler Engineering having graduated from Beijing

Graduate College of North China Power Electric Institute.

AnthraciteFiring_LargestSteamGenerators

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