about mh power systems europe · pdf filebowl & roller mill type mps® the mps®...

MH Power Systems

Europe Service GmbH

is a subsidiary of

Mitsubishi Hitachi

Power Systems Europe GmbH and bundles

the service activities of the company group.

Millsand Components

About MH Power Systems Europe Service

2

MH Power Systems Europe Service GmbH, with about 300 employees, is an inter nationally

active company in the fi eld of power generation, steam generator construction, as well as

for environmental technologies and fi ring equipment. The company’s head offi ce is located

in Duisburg (Germany), with the departments of engineering, boiler and fi ring technology,

mills and components, erection and commissioning and fl ue gas cleaning. In addition,

MH Power Systems Europe Service GmbH operates a centre of excellence for surface engi-

neering (cladding) with a cooperation partner.

With service centres throughout Germany and branches in Europe, Middle East and Asia, MH

Power Systems Europe Service GmbH operates as closely to its customers as possible,

providing its products and specialist skills.

Contents

Components in Typical Coal Power Plants 3

Mill Feeders 4

Pulverisers 6

Burn-Out Grate 13

Ash Removal 14

Other Ash Removal Components 15

Bevel Planetary Gear 16

Replacement Parts Service 17

References 18

MH POWER SYSTEMS EUROPE SERVICE GMBH� Head offi ce in Duisburg, Germany

� German locations

� International locations

Components in Typical Coal Power Plants

Mills and Components 3

Lignite

Bituminous coal

A Steam generator

B Steam lines

C Coal bunker

D Mill feeder

E Coal mill

F Burn-out grate

G Ash removal

H FD fan

a

A Steam generator

B Steam lines

C Coal bunker

D Mill feeder

E Coal mill

F Ash removal

G PA fan

H FD fan

a

Mill Feeders

4

Reliability even under demanding requirements

Designed as coal bunker dischargers, the mill feeders supply the pulverisers with raw coal –

evenly dosed and in keeping with boiler load requirements.

Even when faced with demanding requirements, the mill feeders designed by MH Power

Systems Europe Service operate both reliably and safely.

Experienced MH Power Systems Europe Service staff determine the optimum feeder in keeping

with the requested fuel quantity, design directives (including DIN EN 12952-9, NFPA 85 F)

and customer requirements (for instance, volumetric and gravimetric metering).

Other selection factors are the various bulk material properties, such as coal flow and erosion

behaviour.

Gravimetric coal feeder


In hard coal boiler units, gravimetric coal feeders are used to discharge the raw coal from the

bunker. In lignite plants, drag-chain conveyors together with belt conveyors are used to

discharge the raw coal from the bunker.

Gravimetric coal feeders

The gravimetric coal feeders with corrugated edge belt ensures high outputs, uniform bunker

discharge and continuous mill charging – even at low conveying rates. This design permits volu-

metric / gravimetric metering and quantities conveyed of up to 180 t / h. During normal operation

no conveyed material can fall to the bottom of the feeder due to the design of the corrugated edge

belt. Nevertheless a cleaning device is installed in the bottom section of the feeder to guarantee

the removal of dust deposit. The belt speed is determined by the quantity conveyed. Purge air is

supplied to the housing to stop condensate forming and, in turn, to stop corrosion.

Drag-chain conveyor

Drag-chain conveyors are meant for limited conveyed quantities of up to approx. 40 t / h – this

can, in special cases, be raised to 120 t / h. The fuel is discharged opposite to the direction

of conveying. The drag-chain conveyor principle allows both a compact design with minimum

spacing between bunker discharge and conveyor dumping as well as a possible large spacing

between material charging and dumping.

DB

E

A

A

D

B

C

A Discharge of coal from the bunker

B Conveyance of coal

C Bed depth limitation

D Conveyance of coal

E Discharge to the mill

A Discharge of coal from the bunker

B Conveyance of coal

C Bed depth limitation

D Weighing of coal

E Discharge to the mill

Pulverisers for Bituminous Coal

6

Excellent results

In the mills, the raw coal is simultaneously pulverised, dried and evenly distributed to the coal

burners. Hot air or flue gases transfer the pulverised fuel to the burner and reduce the mois-

ture in the coal.

Bowl & roller mill type MPS®

The MPS® bowl & roller mill by MH Power Systems Europe Service grinds and dries hard

coals and difficult-to-grind lignite with a low moisture content to pulverised fuel and distributes

them evenly directly to the burners.

Mills of various sizes for throughputs ranging from 10 t/h to 200 t/h can be supplied. Constant

refinements and improvements have led to excellent crushing results with high fineness

grades from raw coal found throughout the world. The positive operating properties and low

energy requirements have contributed in no small measure to the success of these mills.

MPS® mill


The performance of vertical spindle mills depends on the geometric dimensions, revolution

speed of the grinding table and the grinding force itself.

By suitable measures at existing plants capacity increase and adaption of the load change

behavior are possible. For example for changed coal characteristics.

As a prerequisite for these mill upgrades, it needs to be ensured that sufficient primary air is

available and that the mill primary air pressure as well as the mill drive power have the required

margins. This necessitates also investigating the mill motor, PA fans and pf-piping in detail.

Implementation of the above measures for variable adjustment of dust fineness during op-

eration, by use of dynamic classifier (type SLS), also secures higher flexibility during load

changes and a temporary increase of pulverised fuel outlet capacity.

MPS® Mill

U.S. Standard Sieve

Particle Size in µm

V6

Pass

ing

(%)

Resi

due

R (%

)

400

63 90 20050 70 150 300 70050030

270 200 100 70 50 30

50

40

30

20

10

1.0

0.1

0.01

60

50.00

60.00

70.00

80.00

90.00

99.00

99.90

99.99

40.00140

V3 V1 V5

0 rpm

110

rpm

100

rpm

85 rp

m

SLS classifier

A Rotary classifier

B Classifier drive

C Grinding rollers

D Hydro-pneumatic system

E Grinding table

F Gear

G Motor

a

Pulverisers for Bituminous Coal

8

Long service life

Tube ball mill type RKD

The MH Power Systems Europe Service RKD tube ball mill grinds and dries difficult-to-

pulverise hard coals (particularly low-volatile coals such as lean coal and anthracite). This mill

type can deal with approx. 150 t / h of coal. Depending on size and space, the tube ball mill

can be designed with drum or neck bearing and be of the single or double pass type.

A Rotary classifier

B Oversize return

C Neck bearing

D Drive gear rim

E Grinding ball filling

F Feed spiral conveyor

G Classifier riser

RKD mill

a


Maintenance of tube ball mill

The maintenance work at tube ball mills includes activities which are carried out while the

mill is in operation and work which requires shutdown of the mill.

Maintenance work during mill outage

■■ Inlet screw conveyors

■■ Inside lining of the inlet and outlet housing

■■ Grinding space armoring

■■ Air sealings

Installation of wear plates

Replacement of screw spirals

Pulverisers for Lignite

10

Low energy requirements

Pulverising lignite is particularly challenging in view of its high moisture content and the

considerable throughputs involved.

Distributor fan beater mill type DGS®

MH Power Systems Europe Service supplies DGS® mills of various sizes up to a 240 t / h

throughput for drying and pulverising raw lignite coals.

DGS® technology involves the raw coal and flue gases being initially put through the pre-

crushing beater section of the beater wheel. This ensures excellent air and coal dust distribu-

tion into the beater wheel. Crushing in

the DGS® mill is usually so intensive

that adequate grinding fineness can be

obtained in one working operation –

without the need for an additional clas-

sifier. This both raises the pressure

balance and cuts back on energy re-

quirements. The DGS® mill has stood

the test of time particularly with

difficult-to-work lignites – something

that explains its considerable lifetime

and unrivalled properties.

a

A Flue gas gate valve

B Inlet housing

C Beater shaft

D Beater wheel

E Coupling

F Motor

G Bearing

DGS® mill


Easy maintenance

Wet fan mill type NV

The NV mills ranging from 10 t/h to 140 t/h throu ghputs are for crushing high moisture

content lignites for direct injection into the furnace.

Together with the flue gases, the raw lignite is brought for crushing purposes into the beater

wheel. It acts as a fan impeller fitted with beater plates. Baffle-type classifiers ensure that

the required fuel fineness for combus-

tion is fulfilled.

The high-tech NV mill more than meets

the ongoing demands worldwide of op-

erational availability and low costs.

a

A Gate valve housing

B Grinding chamber door

C Grinding chamber

D Beater wheel

E Baffle-type classifier

F Double bearing

G Motor

NV mill

Pulverisers for Lignite

12

The grinding system – key component with huge refurbishment potential

Optimised grinding in terms of throughput and grinding fineness and in parallel

minimisation of wear is the target of mill rehabilitations. Even without any firing upgrades,

MH Power Systems Europe Service has attained remarkable plant improvements which

mainly have a positive impact on boiler operation efficiencies.

As a specialist for mills with its own technology, MH Power Systems Europe Service pos-

sesses enormous competence in all kinds of mills and coals for new installations and up-

grades – the latter also for “Non OEM” mills. MH Power Systems Europe Service’s

comprehensive knowledge on grinding and fluid dynamics within the mills / classifiers and their

optimisation potential allows the company to improve matters through simple design meas-

ures backed up by CFD simulation.

DGS® mills, NV mills, N mills for lignite

The main challenge behind a lignite mill upgrade is to optimise the contradictory targets of fuel

throughput and grinding fineness in such a way that the increase of fuel throughput – mostly

in connection with improved grinding fineness – can be obtained with a minimum of wear with

consideration given to the permitted conditions (temperature, oxygen content).

Efficient constructive measures either in the preheater section (for DGS® mills), classifier

(NV, N mills) or in the mill housing are MH Power Systems Europe Service’s specialty for

tapping the full potential of the mill – again supported by CFD simulation.

Exemplary for MH Power Systems Europe Service’s competence is

the upgrade in Nicola Tesla A at fan mill DGS100S. Instead of the requested

contractual throughput increase of almost 10 %, the reasonable measures

which MH Power Systems Europe Service took resulted in a 30 % increase

Burn-Out Grate


High effi ciencies

In lignite coal or peat-fi red plants with a high proportion of xylite or fi bers in the fuel,

the proportion of unburnt residue in the boiler hopper ash can be extremely high and this

impairs fi ring effi ciency.

The optimum designed burn-out grate ensures that the ash burnout in the boiler hopper is

improved to over 80 % – thus substantially raising the overall effi ciency of the boiler plant. In

addition, afterburning results in additional heat input into the boiler hopper, which would

otherwise be relatively cold. This leads to an even distribution of temperature in the furnace.

Asha

j

k

i

Burn-out grate diagram

A Boiler furnace hopper

B Refractory jacket of retarded combustion reactor

C Water seal gasket

D Firmly fi xed grate supporting bars

E Grate carriage

F Grate surface

G Hydraulic system for grate carriage and deashing fl ap

H Ash hopper

I Cooling and combustion air

J Deashing fl ap

K Ash discharge chute

Shutoff gate valve in ash discharge chute

Deasher

Monitoring system

Ash Removal

14

Submerged scraper conveyor functions:

■■ Air sealing to the boiler hopper

■■ Ash cooling

■■ Ash conveying

■■ Inlet for furnace inspection

A Bottom ash

B Transfer chute with immersion piece

C Expansion joint

D Submerged scraper conveyor

E Drive station frequency controlled

F Tensioning station

G Idler stations

H Discharge chute

I Cooling water inlet

J Overflow

K Travelling rails

Submerged scraper conveyor

Stable in the extreme and long lasting

Ash removal systems have been part of MH Power Systems Europe Service’s range of products

and supplies for many years now. This applies to bottom ash removal as well as to the transfer

of ash accumulat- ing in the course of air heater and electrostatic precipitator ash removal.

i

k k j k k

a

a i

k j k k

Submerged scraper conveyor for hard coal-fired systems

Submerged scraper conveyor for lignite-fired systems

➞➞Conveying direction

Other Ash Removal Components


MH Power Systems Europe Service provides a broad range of ash handling systems. These

systems apply to ash handling for furnace bottom ash removal and also to the ash removal

from all downstream ash accumulation points.

Our systems offer a lot of benefits: they are stable in the extreme, wear parts are long lasting

and both the energy requirements and operating / upkeep costs are low. MH Power Systems

Europe Service provides the entire range for utility steam generators with pulverised hard coal

and lignite firing: from design, manufacturing and erection up to commissioning the complete

ash disposal systems including loading systems for transport by truck, rail and ship.

Components

■■ Ash silos and dewatering bunker

■■ Single-strand chain conveyors

■■ Apron conveyor

■■ Screw conveyors

■■ Single and double roller crushers

■■ Hammer crushers

■■ Rotary feeders

■■ Single and double pendulum flap

■■ Shut off gates

■■ Ejectors

■■ Bucket-type conveyors

■■ Sluice ways

Ash removal systems

■■ Dry mechanical ash removal systems

■■ Hydraulic ash removal systems

■■ Pneumatic ash removal systems

■■ Mill reject systems

■■ Re-cooling systems for submerged conveyor overflow water

Bevel Planetary Gear

16

A Output flange

B Tilting pad thrust bearing

C Planetary wheel

D Tooth coupling

E Bevel wheel

F Hollow wheel Carrier

G Planet

H Sun wheel

I Driving shaft

J Casing

KPV gear unit

Highest availability

Gear unit type KPV

The MH Power Systems Europe Service gear unit type KPV, for vertical spindle mills, is a

two-stage planetary bevel gearing with a bevel wheel stage and a planetary gear stage. The

driving shaft is arranged horizontally, the bevel wheel shaft, planet wheel set and output flange

are mounted vertically. The bevel wheel stage is connected with the planetary gear stage by

a toothed coupling. To sustain the static and dynamic axial forces from the mill a tilting pad

thrust bearing is installed in the upper casing section.

a

i

j

Replacement Parts Service


As a designer and manufacturer of original components, MH Power Systems Europe Service

is the ideal partner to contact when modernization or replacement parts are needed.

Our extensive expertise derived from designing and delivering utility steam generators

with the associated components over many years enables our MH Power Systems Europe

Service experts to provide professional solutions matched to customer requirements in the

matter of plant design and operations. Optimized plants ensure that performance and avail-

ability are raised and that effi cient operations are attained as far as possible. As a competent

and fl exible partner, MH Power Systems Europe Service’s expertise is available in the fi elds

of process engineering, plant optimization, measuring technology, plant-internal inspection,

component installation and commissioning. At the same time, MH Power Systems Europe

Service supports customers in the design and confi guration of their future plants – from the

technical point of view (planning, design, optimizing) and in the matter of operating economy

analyses.

Rapid service from a competent partnerManufacturing from a single sourceAs stakeholder in Babcock Ferti-gungszentrum GmbH in Oberhau-sen, we are in the closest possible contact with our partners and, as such, are fl exible and quick in handling your enquiries and can provide you with dependable solutions.

Mill Feeders Pulverisers Burners Ash submerged scraper conveyors

Belts Wear partsPulverised fuel line elbows

Chains

Chains Linings Pulverised fuel lines Scraper bars

Drives Nozzle rings Impact plates Wear plates

Bearings Shaft seals Housings Drives

Gate valves Feeding screw conveyors

Adjusting mechanisms

Conveyor-type weighers

Beater sections Bearings

Expansion joints Gear units

Drives

MH Power Systems Europe Service GmbH

24h Hotline + 49 172 2608481

References

18

Projects / products of MH Power Systems Europe Service (selection)

Project Technology Capacity Design

Kusile Unit 1 – 6 South Africa

Bituminous coal fired boiler

6 x 800 MW 117 t/h

Belt conveyor, according to NFPA 3.5 bar 6 x 5 MPS® mill, size 265 incl. gear box Submerged scraper conveyor

Medupi Unit 6 – 1 South Afric a


6 x 794 MW 114 t/h

Belt conveyor, according to NFPA 3.5 bar 6 x 5 MPS® mill, size 265 incl. gear box Submerged scraper conveyor

Maasvlakte Netherlands


1,100 MW 84 t/h

Belt conveyor, according to TRD 1.0 bar 5 MPS® mill, size 255 incl. gear box Submerged scraper conveyor

Duke Cliffside USA


900 MW 72 t/h

6 MPS® mill, size 235 incl. gear box

Datteln 4 Germany


1,100 MW 84 t/h

Belt conveyor, according to TRD 1.0 bar 5 MPS® mill, size 255 incl. gear box Submerged scraper conveyor

Moorburg Unit A + B Germany


2 x 820 MW 76 t/h

Belt conveyor, according to TRD 1.0 bar 2 x 4 MPS® mill, size 245 incl. gear box Submerged scraper conveyor

Rotterdam Netherlands


800 MW 65 t/h

Belt conveyor, according to TRD 1.0 bar 4 MPS® mill, size 225 incl. gear box

Wilhelmshaven Germany


800 MW 65 t/h


Walsum 10 Germany


750 MW 68 t/h


Genesee Power Generation Station Phase 3 Canada


495 MW 58.9 t/h


Shentou II Power Plant Phase 2 China


2 x 500 MW 60.5 t/h

2 x 6 MPS® mill, size 225 incl. gear box

Kogan Creek Australia


750 MW 80 t/h

Belt conveyor, according to NFPA 3.5 bar 6 MPS® mill, size 255 incl. gear box

Mid American Energy Company USA


830 MW 80 t/h


Shanxi Wangqu Thermal Power Plant China


2 x 600 MW 51.6 t/h

2 x 6 MPS® mill, size 200 incl. gear box

Paroseni Co-Generation Power Plant Romania


180 MW 39.5 t/h

Belt conveyor, according to NFPA 3.5 bar 4 MPS® mill, size 212 incl. gear box

Iskenderun Sugözü Power Plant Turkey


2 x 605 MW 77.8 t/h

Belt conveyor, according to TRD 1.0 bar 2 x 4 MPS® mill, size 255 incl. gear box

Boxberg R Germany

Lignite coal fired boiler

660 MW 113 t/h

8 NV mill, size 110 Submerged scraper conveyor

Boxberg Q Germany


900 MW 140 t/h

8 NV mill, size 130 Submerged scraper conveyor

Lippendorf III Germany


933 MW 116 t/h

8 NV mill, size 110

Megalopolis IV Greece


850 MW 956.4 t/h (steam)

6 DGS® mill, size 180 Submerged scraper conveyor

Elbistan B Turkey


4 x 360 MW 4 x 1,037 t/h (steam)

4 x 6 DGS® mill, size 180

Schkopau Germany


2 x 450 MW 2 x 1,365 t/h (steam)

2 x 8 DGS® mill, size 65

Dezhou Unit 2 + 1 China

Special fuels fired boiler

70 t/h 2 x 6 RKD mill, size 420 x 650 Submerged scraper conveyor

Lausward Unit D + B Germany


46 t/h 2 RKD mill, size 340 x 500

Lausward Unit A1 Germany


28 t/h 1 RKD mill, size 340 x 500

Herne 4 Germany


500 MW 85 t/h

3 RKD mill, size 500 x 700

Herne 3 Germany


300 MW 55 t/h

2 RKD mill, size 440 x 650


Service / retrofit activities for grinding and firing systems (selection)

Project Technology Capacity Work carried out

Kostolac B2 Serbia


330 MW 8 N270.45 Retrofit / replace of classifier, coal change, capacity increase, improved classifier outlet fineness

Mega IV Greece


650 MW 8 DGS® 180 Retrofit / replace of classifier, coal change, capacity increase, improved classifier outlet fineness

Nicola Tesla A5 Serbia


330 MW 6 DGS® 100 Retrofit / replace of burners and mills, revolution grinding desk / beater wheel, coal change, capacity increase, improved classifier outlet fineness, low NOX firing

Weisweiler F / E Germany


2 x 300 MW / 2 x 300 MW

2 x 6 DGS® 60 / 2 x 6 DGS® 60 Retrofit / replace of mills, coal change, capacity increase

Mehrum Germany


650 MW 3 MPS® 190 Retrofit / replace of classifier, coal change, capacity increase, improved classifier outlet fineness

Nicola Tesla A4 /A3 Serbia


330 MW / 330 MW

6 DGS® 100 / 4 DGS® 100 Retrofit / replace of mills, revolution grinding desk / beater wheel, coal change, capacity increase, improved classifier outlet fineness

Weisweiler D / G + H Germany


300 MW / 600 MW

8 N80.75 / 8 DGS® 130 Retrofit / replace of mills, coal change, capacity increase

Mega IV Greece


650 MW Bottom ash Retrofit / replace of bottom ash handling, higher unit availability

Buschhaus Germany


650 MW 6 DGS® 90 Retrofit / replace of classifier, coal change, capacity increase

Wilhelmshaven Germany


720 MW 4 MPS® 225 Nozzle ring, higher unit availability

Kiel Germany


320 MW 4 MPS® 180 Retrofit / replace of classifier, coal change, capacity increase

Heyden Germany


900 MW 4 MPS® 255 adjustable grinding force, revolution grinding desk / beater wheel, retrofit / replace of P.F. pipes, coal change, capacity increase

Amer Netherlands

Biomass fired boiler

600 MW 6 MPS® 235 Retrofit / replace of mill, biomass grinding

Veltheim Germany


330 MW MPS® 150 Retrofit / replace of classifier and mill, coal change, capacity increase, reducing of unburnt carbon, improved classifier outlet fineness

Reuter Germany


320 MW MPS® 170 Retrofit / replace of burners, classifier, p.f. pipes and sealing air system, low NOX firing, reducing of unburnt carbon, improved classifier outlet fineness

Milliken USA


150 MW MPS® 150 Retrofit / replace of mill air fans, classifier, mill, P.F. pipes and sealing air system, coal change, capacity increase, low NOX firing, improved classifier outlet fineness

MITSUBISHI HITACHI POWER SYSTEMS

EUROPE GMBH

Schifferstraße 80, 47059 Duisburg, Germany

Phone +49 203 8038-0, Fax +49 203 8038-1809

[email protected], www.eu.mhps.com

Service Emergency Number +49 172 2608481

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about mh power systems europe · pdf filebowl & roller mill type mps® the mps®...

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