Modernization - Hitachi Power Europe GmbH

Modernization 

of Combustion Systems

Hitachi Power Europe 

2 

Contents 

Modernization of 

Combustion Systems 

Key for a Successful 

3 

Rehabilitation Project 4 

Competence in Firing Systems 8 

Our Own Manufacturing Facilities 9 

Success Products 

Solutions to Increasing 

10 

Plant Flexibility 18 

Rehabilitations – References 20 

Inspire the Next 22 

1 2 

Technology Leader with Excellent References 

Whether as a plant constructor or as a supplier of key components, Hitachi Power Europe 

GmbH (HPE) is one of the technology and market leaders in fossil-fired power plants. 

The company – a subsidiary of Hitachi, Ltd. – has its head offices in Duisburg. HPE designs 

and builds not only power plants but also supplies all the key components such as utility 

steam generators, environmental engineering equipment, turbines and pulverizers. In so 

doing, HPE can turn back to a track record going back over many years, an extensive list 

of references and to the outstanding know-how of its workforce. Within the Hitachi Group, 

HPE is responsible for the markets in Europe, Africa, Russia (incl. Belarus) and India. 

4 

6 

5 

Hitachi Power Europe GmbH, Duisburg 

Babcock Fertigungszentrum GmbH, Oberhausen 

BGR Boilers Private Ltd., Chennai 

Donges SteelTec GmbH, Darmstadt 

5 Hitachi Power Africa (Pty) Ltd., Johannesburg 

6 Meeraner Dampfkesselbau GmbH, Meerane 

3

Modernization of Combustion Systems 

Low Emission and Flexibility Issues 

Present developments on the energy market are enlarging the wide portfolio of modernization 

schemes by flexibility issues as, in the future, conventional power plants will be facing 

competition for power production during those limited and fluctuating time cycles caused 

by increased production from renewable energies. 

Modernization measures usually comprise 

■■Increase of availability, efficiency and performance 

■■Optimization of combustion process, reduction of emissions 

■■Lifetime extensions 

This is extended nowadays by flexibility issues like 

■■Load ramp enhancement 

■■Startup / low load optimization 

■■Fuel alternatives (fuel change, biomass, pre-dried pulverized fuel, skip of oil / gas) 

■■Pulverized fuel storage 

Complex measures are required to operate existing units economically under these new 

market conditions. Here modernization of the firing system plays a key role. HPE, as a 

modern technology supplier with many years of competence in the worldwide new-built 

and rehabilitation business, is on hand both for classic rehabilitation and the new tasks. 

Combustion solutions 

using HPE’s 

innovative swirl 

burner technology 

for all fuels 

For all modernization work involving the combustion 

process, HPE delivers – based on its own technology and 

key components * – the required advanced 

Milling technology 

(lignite, bituminous 

coal) 

Coal feeder 

and deashing 

technology 

in combination with a wealth of experience with other components like fans, air heaters, soot blowers and 

pumps from ongoing contracts 

* See also HPE brochure: Solid Fuel Firing Systems and Components 

Pressure parts, 

ductworks 

Modernization of Combustion Systems 3

Key for a Successful Rehabilitation Project 

4 

Own Engineering and Technology 

Within the last 30 years HPE has gained experience from more than 550 modernization 

schemes, rehabilitation work and studies worldwide and thus HPE is your partner for 

challenging rehabilitation undertakings for the entire boiler. 

Overall Rehabilitation 

Performance Increase 42% 

Upgrade of 

Combustion System 

NO X Reduction 19% 

HPE’s primary interest is the engineering driven concept of design for best solutions as 

well as supplying its own key components – with labor intensive manufacturing as well 

as dismantling / erection work to be executed by local partners (advised / supervised by HPE 

specialists) or by power plant staff. 

HPE offers advantages in technology and competence for your project 

■■Experienced acknowledged specialists and contact partners 

■■Own product development (patents), own software development – 

partly in Hitachi wide cooperation 

■■Active participation (project leader) in essential research activities 

■■Parametric design, supported by up-to-date tools (PDS, ProE) 

■■Accredited own laboratory for coal, ash and damage analysis 

Increase of Efficiency 

19% and Availability 

Redesign of 

Firing System 

10% Fuel Change 

Lifetime Extension / 

10% Others 

■■Experience gained from worldwide commissioning and operation of ongoing plants 

■■CFD simulation (Computational Fluid Dynamic calculations) to support design concepts

Co-operative Approach 

We are your partner for complex rehabilitation work in which – through process optimization 

of plants and components – remarkable economic and ecological improvements are 

gained. This can even come from a simple design solution supported by CFD simulation 

calculations. HPE has already designed the most effective of concepts in instances of 

where the OEM’s solutions have failed. 

Your detailed plant / 

component expertise 

including knowledge 

about damage and 

malfunctions as well 

as your draft ideas for 

improvement. 

Upfront of a potential rehabilitation HPE offers engineering concepts for a common stepwise 

approach: 

Time and Budget Saving Procedure for a Solution Demonstration 

Basis of the Ultimate Solution 

Detailed Study 

Common 

Investigation 

for Problem 

Analysis 

The benefits 

■■HPE’s proven cost- and time efficient way of proceeding for identification of 

potential measures 

Our experts’ knowledge 

+ = 

about solutions and expe- Bundled “hand in hand” 

rience obtained in similar knowledge as best basis 

applications worldwide. * for the project, from 

* Example: Similar grinding / 

the first idea up to 

firing topics in the Balkans and successful completion. 

Australia 

ExPERiEnCE ExCHanGE with plant staff 

HPE REviEW of plant data 

UPGRaDE OF PilOT EqUiPMEnT 

for demonstration purposes 

UPGRaDE COnCEPT (by HPE) supported by 

CFD simulation with budget indication 

SiTE invESTiGaTiOn Mill measurement 

program and coal /ash analysis by HPE 

■■Development of effective measures for complete rehabilitation to schedule 

■■Risk limitation due to solutions supported by Simulation Calculations (CFD) 

Should you be interested, we are more than ready to discuss these steps in detail with you. 


Key for a Successful Rehabilitation Project 

6 

CFD Simulation Calculations 

CFD programs can be applied by many users. However without validation by reality and 

associated calibration, the results may not serve as a reliable design support. 

For HPE these programs are essential as valuable tools in supporting concept developments. 

For this reason, HPE is very much interested in permanently calibrating those programs for 

simulation of fluid dynamics and emissions from its own know-how and latest HPE supplier 

experience. The aim of this validation is to have a reliable tool during the design stage to 

simulate the reality for even complex issues. 

By application of these calibrated CFD programs, verification is undertaken of HPE’s engi- 

neered solution for optimization of the components or complete plants. 

Feedback from Reality 

■■Hitachi’s own test facilities 

■■Intensive research and 

development activities 

■■HPE’s own laboratory 

(accredited DIN EN ISO / IEC 17025) 

■■HPE’s own commissioning 

experts / activities 

■■Testing of research findings 

in utility plants 

■■Operation experience from 

utility plants 

■■Many years of Babcock / Hitachi 

know-how 

■■Hitachi’s internal (German-Japan) 

experience exchange for 

continuous optimization and 

development of the latest calculation 

methods

Visualization of Improvements 

Thus for potential rehabilitation purposes, both the existing situation with related problems 

as well as the future situation can be demonstrated after implementation of HPE’s concept 

from an impressive visual comparison – this is done during the early stage without 

affecting the plant – and under reasonable costs. 

latest Developments 

Meanwhile the development of the simulation programs has been extended with the result that 

■■Dynamics of ignition and combustion process at burners as well as 

■■Location and rate of wear, e. g. in PF ducts 

can be impressively simulated; the latter being an important forecasting element for the service 

and maintenance department. 

Existing Situation HPE Upgrade Concept 

Same task for similar mills (Serbia /Australia) 

This procedure from CFD simulation support has proven to be successful. Based on key 

boiler data and parameters, coal / ash analysis as well as information about malfunction, 

studies enable HPE to evaluate the intended rehabilitation measures. 

In line with the given project task, HPE defines the required scope of measures and related 

guarantee values and evaluates budget requirements. 


Competence in Firing Systems 

8 

Main Driver for Plant Improvement 

Process optimization of the combustion process together with the most advanced grinding 

and firing equipment allow HPE to offer efficient rehabilitation work at reasonable costs. 

Solutions for burners, grinding equipment as well as the furnace – which have been refined 

for over 10 years now – are optimized using the above simulation calculations. Typical firing 

problems which can lead to inefficient operations, unnecessary emissions or even plant 

damage are the following: 

■■Unstable coal firing 

■■Support firing 

■■Over-high emissions (NOX, CO) 

■■Problems with fuel change-overs 

■■Incomplete combustion (high UBC values) 

■■Over-high furnace end temperature (FEGT) 

■■Slagging / fouling problems 

■■Furnace wall corrosion 

As a rule, in order to reach optimization targets on a sustainable basis, all related systems like 

grinding equipment, burners and the furnace need to be considered as a whole. Optimized 

grinding is the key to successful firing rehabilitation. Related mill measurements on existing 

plants provide valuable information on the optimization potential. Improved grinding perfor- 

mance in combination with HPE’s modern burner generation represent proven solutions for 

sustainable boiler modernization. However, for successful low NO X firing rehabilitation, infil- 

trated air needs to be reduced – it should not exceed 15 % (lignite) or 5 % (bituminous coal) 

at furnace exit. Therefore, seal tightness issues also need to be considered – something 

which is also beneficial for economic plant operation. 

Boiler Height /Flue Gas Path 

Low NO x Rehabilitation: 

Temperature Profiles 

Existing: Jet Burner 

λ = 1.29 no OFA 

Furnace Exit 

➔ Over Fire Air 

Burner 

Zone 

Typical 

Flue Gas Temperature 

New: RS ® Burner 

λ = 1.18 with OFA 

not only mills and burners 

In connection with a rehabilitation of the firing 

equipment, HPE also analyses the impact of 

changes in boiler heat transfer due to com- 

bustion air reduction – as it is the case with 

most low NO X rehabilitations (see also typical 

sketch for a revamp with RS ® Burners). 

Given obvious variations, we would propose 

measures to secure the original steam 

parameters either at the turbine entry or 

at the district heating extraction system.

Our Own Manufacturing Facilities 

Maximum Quality 

in contrast to most other solution provider, Hitachi Power Europe can utilize its own 

manufacturing. 

This includes pressure parts for utility steam generators and headers (at “Meeraner Dampf- 

kesselbau GmbH”), coal mills and burners (“Babcock Fertigungszentrum GmbH”), material 

handling systems and steel structures (“Donges SteelTec GmbH”). As a result, HPE is not 

primarily tied to sub-contractors and creates a true “Alliance for Quality”. 

Maximum quality is needed in power plant engineering particularly since components are 

subject to considerable stresses and must dependably perform their functions for decades 

under continuous operations. That is why HPE’s subsidiaries have established special priori- 

ties in controlling production quality. Thanks to constant refinements in high-tech materials 

involving, for instance, special alloys for pressure parts, components can be used even more 

economically and in a more environmentally compatible manner. Based on this experience 

and depending on the project prerequisites, co-operation with local partners is also an option. 



Exemplary for HPE’s competence is 

the upgrade in Weisweiler PP at fan mill 

N80.75. Instead of the requested contractual 

throughput increase of almost 10 %, 

the reasonable measures which HPE took 

resulted in a 40 % increase 

10 

The Grinding System – 

Key Component with Huge Refurbishment Potential 

Optimized grinding in terms of throughput and grinding fineness and by in parallel 

minimization of wear is the goal of mill rehabilitations. Even without any firing upgrades, 

HPE has attained remarkable plant improvements which, in the main, have impacted 

positively on boiler operation efficiencies. 

As a specialist for mills with its own technology, HPE possesses enormous competence in all 

kinds of mills and coals for new installations and upgrades – the latter also for “Non OEM” 

mills. HPE’s comprehensive knowledge on grinding and fluid dynamics within the mills / 

classifiers and their optimization potential allows the company to improve matters through 

simple design measures backed up by CFD simulation. 

DGS ® Mills, NV Mills, N Mills for Lignite 

The main challenge behind a lignite mill upgrade is to optimize 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 by a minimum of 

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

Performance can often be improved remarkably without the need to invest in any increase of 

fan wheel speed or fan wheel diameter – something usually requiring either an upgrade or 

replacement of, for instance, the wheel itself, shafts, bearings, drive and coupling. 

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

(NV, N mills) or in the mill housing are HPE’s specialty for tapping the full potential of the 

mill – again supported by cfd simulation.

MPS ® Mills for Bituminous Coal 

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

speed of the grinding table and the grinding force itself. 

MPS ® Mill 

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

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

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

Application of the above measures for variable adjustment of dust fineness during operation 

also secures higher flexibility during load changes and a temporary increase of pulverized fuel 

outlet capacity. 

SLS Classifier – 

latest classifier design 

Passing (%) 

99.99 

99.90 

99.00 

90.00 

80.00 

70.00 

60.00 

50.00 

30 

Particle Size in µm 

50 63 70 90 150 200 300 500 700 

V3 V1 V5 

0.01 

110 rpm 

100 rpm 

85 rpm 

40.00 

400 270 200 140 100 70 50 30 

U.S. Standard Sieve 

0 rpm 

0.1 

1.0 

V6 

10 

20 

30 

40 

50 

60 

Residue R (%) 

Measures for increasing grinding capacity: 

■ Conversion of existing gearbox or 

replacement by new gearbox to increase 

the mill table speed 

■ Implementation of an adjustable hydraulic 

grinding force system 

■ Increase of maximal grinding forces by 

reinforcement of bearings, drives, tension 

frame, tension rod, hydraulic system, etc. 

■ Optimization and new design of grinding 

rollers and grinding segments 

with the latter two being complex solutions 

securing capacity increases of up to 60 % 

Measures for improved grinding fineness 

(steeper distribution curve): 

■ Replacement with new dynamic classifiers, 

often in existing classifier house 

■ Classifier drive equipped with frequency 

inverters 

Both comparatively simple conversions 

which by maintaining pulverized fuel fineness 

increase mill throughput by up to 10 % 



12 

HPE Burner Fleet 

lignite / 

brown Coal 

Sub 

bituminous 

State-of-the-art Combustion with Proven Burners 

from HPE 

HPE’s ongoing burner fleet covers the whole fuel range for thermal applications 

■■For all fossil fuels – from anthracite via bituminous and sub-bituminous coal up to lignite, 

including pre-dried lignite as well as different kinds of oil and gas qualities 

■■For many biomass applications and their dried or torrefied variants 

bituminous anthracite biomass 

(co-firing) 

All burners are based on the same design philosophy, which derives from HPE experts’ 

knowledge and detailed understanding about the ignition and combustion process. 

Full combustion control 

HPE’s burners are characterized by excellent ignition thus ensuring controlled combustion 

over a wide range together with high flame stability and low emission values. Due to their 

features the burners can cope admirably with high fuel flexibility. Firing systems designed for 

problematical coals can be significantly simplified. HPE’s burners are designed for stoichio- 

metric conditions. This impacts positively on the fouling and slagging behavior – even with the 

properties of problematical fuels – and optimally protects the furnace walls against corrosive 

flue gas products. 

biomass 

(stand-alone) 

pf dried pf dried pf dried pf dried pf dried pf dried 

The principle of staged burner design is focused on fuel treatment to prepare the particles for 

pyrolysis and ignition under the required conditions. The characteristic features are expressed 

Oil / 

Gas 

bFG Turn down ratio 

(Control range) 

by the definition of initiation and course of ignition – with the latter meeting the equation: 

IGNITION = PYROLYSIS + OXIDATION 

burner 

Size MW th 

DS ® X X X X X 1 : 3.5 20 – 100 

RS ® X X X 1 : 2 30 – 80 

DST X X X X X X 1 : 17 20 – 60 

ADS X 1 : 4 10 – 60 

SG X 1 : 2 20 – 60

All HPE burners are of concentric design with swirl flow in all sections and devices such 

as fuel nozzle and deflection cones. The CFD supported design ensures best combustion 

performance in line with fuel and furnace requirements. 

All burners apply staged combustion as an intermediate sub-stoichiometric primary flame 

securing low NO X values, combined with sufficient secondary / tertiary air supply even for 

over-stoichiometric combustion. 

Following operational highlights characterize HPE-patented burners 

■■Excellent flame stability even under high fuel flexibility 

■■Stable flame attachment to the fuel nozzle 

■■Extensive burner control range with good part load performance 

■■Very low NOX emissions due to focus on pyrolysis and ignition processes 

■■Benefits of stoichiometric / overstoichiometric operation 

(less fouling / slagging, corrosion protection) 

■■Easy replacement or adaptation to existing burner 

■■Minimum wear with a minimum 5 years / 24,000 hrs. lifetime guaranteed 

Secondary Air Swirler – CFD Optimized Design 



DS ® Burners are also suitable for 

biomass co-combustion, as shown with 

DS ® Burner flame (35 MW), 

co-combustion coal (60 %) + sawdust (40 %) 

14 

DS ® Burner for Bituminous Coal 

DS ® Burner 

Igniter 

Pulverized Fuel 

Core Air 

Adjustable Swirlers 

DS ® burners were introduced early in the 1990s and continuously developed over the 

years. Since 1992 more than 1,500 burners of this type have been successfully placed into 

operation and applied both in new installations and rehabilitations. This staged burner type 

can be used in direct firing systems for nearly all kinds of pulverized solid fuel qualities. 

The burner has a concentric design with swirled flow streams in all burner sections. The DS ® 

Burner is the first of its kind enabling the above controlled ignition and staged combustion 

process. It represents the basis model for the development of the other burner types. Due to 

its excellent flame stability, the DS ® Burner comes up with a control range of 1: 3.8 whereas 

normal coal burners are limited to 1: 2. The burner is suitable for individual combustion air 

supply as well as windbox arrangements. 

DS ® W Burner Design for a Windbox Arrangement 

Secondary Air 

Tertiary Air 

Fuel Nozzle

RS ® Burner for Lignite 

RS ® Burner 

logical progression of a successful burner generation comes in the form of RS ® burner 

development for lignite combustion. in contrast to conventional jet burners, the innovative 

RS ® burner concept is focused on stable fuel ignition at the burner tip. 

This principle coming from DS ® Burner technology has proved its success in many applications 

where existing jet burners have been completely refurbished by burners of this type. Close on 

150 burners have been installed at a total of 10 boilers. 

The new boiler at Boxberg Unit R (670 MW – commissioned by end of 2011) is the first of 

its kind which is equipped with RS ® Burners in an “all-wall-firing concept”. This convincing 

concept – from the arrangement point of view as well – will be applied in all new lignite boilers 

designed by HPE. 

Total control over the lignite combustion process 

Under the requirement of keeping to the requested NO X emission values, the RS ® Burners permit 

over-stoichiometric operations – in contrast to jet burners. This has the following advantages: 

■■Reduction of multiple overfire air elevations 

■■Reduction of a slagging tendency due to convenient combustion air supply 

■■Protection against furnace wall corrosion, especially in cases of high fuel sulfur content 

HPE’s main interest within firing rehabilitation lies in replacing jet burners by RS ® Burners with 

their favorable operational behavior. It has been proved that this leads to a sustainable solution 

of all firing problems. 

Secondary Air 

Fuel Nozzle 

N. B. Where no RS ® Burner refurbishment is intended (e. g. due to budget reasons), HPE 

can, of course, also upgrade existing jet burners with RS ® Burner functionality being used 

as much as possible. Precondition: HPE’s internal pre-investigation demonstrates that this 

is an appropriate measure for meeting the guaranteed performance values. 

In contrast to the squared jet burners the 

circular-shaped RS ® Burners are equipped 

with the described features 

For further technical details also consult 

the HPE flyer “RS ® Burner” 



16 

Biomass, e. g. in the form of 

pellets or woodchips, can be used 

in HPE’s DST Burners 

DST Burner for all Pre-dried Pulverized Fuels 

DST Burner 

Igniter 

Pulverized Fuel 

Core Air 

Swirlers 

The DST burner has recently been developed on the basis of the DS ® burner concept for use 

in indirect firing systems. This burner type is the right one for all kinds of pre-dried pulver- 

ized fuels. Pulverized fuel loading can be amount from 0.5 kg up to 15 kg fuel / kg medium. 

These burners have a considerable turndown rate of up to 1:17 and are thus ideal in support- 

ing flexibility issues. DST Burners can be used for atmospheric operation or in pressurized 

systems with air and / or oxyfuel atmosphere. Air, inert gas and flue gas with or without oxygen 

enrichment can be used as the delivery medium. An extensive testing program has come up 

with a convincing performance in a burner test facility as well as during the test period at the 

Oxyfuel pilot plant at the Schwarze Pumpe site. 

Secondary Air 

Tertiary Air 

Fuel Nozzle

ADS Burner – Oil / Gas 

ADS Burner 

Oil Gun 

Adjustable Swirler 

aDS burners are HPE’s low-nO X answer to the combustion questions surrounding liquid 

and gaseous fuels and which are used with industrial boilers and utility steam generators. 

They can be designed as single fuel type burners and for multi-fuel operation. ADS Burners 

are available for the front wall, opposed installation or as bottom burners; they are also used 

as startup burners in utility units. 

SG Burner – BFG 

SG Burners are used for low calorific fuel like Blast Furnace Gas (BFG / BOFG), mulitfuel 

applications like COG, NG and oil. For best combustion performance, fuel and air flows are 

also influenced by swirlers and other devices. 

SG Burner – BFG 

Secondary Air 

Swirler 

Secondary Air BFG 

NG Primary Air 

Multi-Spot Gas Nozzles 

Oil Nozzle 

COG 

Igniter 

Oil Gun 

Contours of temperature: 

Eshkol Power Station ADS Burner 

for Gas Firing 


Solutions to Increasing Plant Flexibility 

18 

Priority in Future Plant Optimization is Shifting 

in the past, the main issues have been efficiency and availability for producing power 

under best economic conditions from a maximum of plant utilization. in future, besides the 

network stability requirement there is also the challenge – even from reduced efficiency 

and on fulfilling the progressively tougher emission values – of generating and selling 

power as often as possible on the power market during the limited high price conditions 

so as to secure plant commercial feasibility. 

Related challenges of future flexible coal unit operations are 

■■Good part load properties combined with a steeper load ramp 

■■Frequent startups 

■■Extension of coal operation down to lowest minimum load (1-mill operation) 

■■Reduction / avoidance of valuable oil / gas during start up, low load 

■■Everything done with consideration given to the existing emission limits (mainly NOX) From the firing point of view, HPE has suitable concepts supported by modern low emission 

burner technology as described above. Moreover, HPE also possesses concepts for indirect 

firing. During energetic optimized operation and / or during low power prices, fuels are ground 

and stored independently from the boiler operation and on request are immediately available. 

The related integration into existing plants – also in connection with optional utilization of 

dried biomass – was investigated by HPE in several studies and is ready for implementation. 

Solutions to reduce oil and gas under startup optimization conditions also exist. System 

warming by hot gas heating of only one MPS ® mill allows early coal fire for that one mill. 

This, in turn, takes over overall system heating for the full coal operation, thus considerably 

reducing expensive start-up fuels. Startup technologies without oil / gas are being developed. 

Fuel flexibility solution (biomass conversion) 

In Europe the trend is towards CO2-neutral combustion of biomass such as wood chips, 

wood pellets, saw powder and plants / fruits as residues (corn, husk of citrus fruits, olive pits 

etc.) and torrefied variants. To this end, HPE recommends boiler modifications for cocombustion 

of biomass in utility size plants to avoid high investment cost in new plant. HPE 

has suitable burners for solid biofuels as well as references and concepts for handling, 

storage and fuel preparation – and this in partly modified bituminous coal and lignite mills. 

Precondition for flexibility – Upfront comprehensive investigation 

All the systems involved and their elements such as steam, combustion, flue gas cleaning etc. 

need to be investigated in detail as to their eligibility for the intended operational mode. 

The main criteria such as full load, NOX emissions, boiler performance, plant integration 

and adaptation requirements for fuel logistics – including explosion protection for biomass 

application – also need to be considered. HPE has the required expertise in overall solutions 

for all kinds of flexibility upgrades.

G 

 

DST Burner 

100% Biomass 

Capable 

Conveying 

Cyclone 

Coal 

Dust 

Bunker 

An appropriate configuration of existing technologies will not only significantly increase flexibility 

of a coal-fired power plant (also one that is optionally biomass-fueled) but also contribute – 

from cost savings – to greater plant competitiveness. The above scheme shows how to 

retrofit a conventional fossil-fueled power plant into a hybrid-fueled, high load and operationally 

flexible power plant – one which assures a maximum utilization of renewable sources and 

production of additionally combined heat and power. 

By upgrading the firing system with an indirect firing capability it is possible to reduce the 

minimum firing rate by approx. 15 %, if permitted by the burner control range. In conjunction 

with a retrofit utilizing DST Burners the minimum firing rate can be lowered to about 10 % 

thanks to the burners’ wide control range. Below 10 % electrical power can be generated by 

using a connected gas turbine, as in the case of gas turbine repowering 5. Implementing an 

indirect firing system makes it possible to reach the designed ramp rates of newly build or older 

boilers; a reduction of thickness of thick walled components clears the way for reaching a 

possible ramp rate of up to 10 % / min. Further ramp rate improvements come from gas turbine 

repower ing 5. Thus repowering / topping – using gas turbines either in combined mode 

or recovery preheating – makes it possible to improve flexibility by combining two different 

generation types in a smart way. It also enables the gross power output to be increased, plant 

efficiency enhanced and CO2 emissions cut. The latter can also be achieved by using an 

indirect firing system combined with DST Burners burning (e. g.) woody biomass . 

Operation improvements 

■■Up to 90 % of costly support fuel can be saved by switching very quickly to 

minimum stable coal / biomass load during start up. 

■■Mill operation for the indirect firing system – preferable during off-peak times – 

enhances efficiency due to constant mill speed in the optimum energetic range. 

■■Reducing auxiliary power consumption by introducing frequency speed control 

to induced and forced draught fans additionally elevates part load efficiency. 

 

 

Fan 

Air 

 

Raw Coal 

Bunker 

Minimum Load 

40 % 

 

30 

20 

10 

0 

10 

8 

6 

4 

 

 

12 % 

Ramp Rate 

 

 

Indirect firing 

Power Output 

+30 Δ% 

+20 

 

+10 

Modernization of Combustion Systems 19 

0 

Plant Efficiency 

+3 Δ% 

 

+2 

+1 

0 

CO2 Emissions 

0 Δ% 

 

–10 

–20 

 

–30 

Reduced wall thickness and 

increase in number of separators / headers 

DST Burner 

100 % biomass capable 

5 GT repowering

Rehabilitations – References 

Mill Upgrading – Extract 

Power Plant 

Country / MW / Fuel 

Frimmersdorf Q 

Germany / 300 MW / Lig 

Nanticoke 

Canada / 512 MW / Bit 

Reuter 

Germany / 320 MW / Bit 

Elverlingsen 


Veltheim 


Oroszlany 

Hungary / 60 MW / Lig 

Neurath C 


Wilhelmshaven 


Niederaußem B 


Amer 9 

Netherlands / 600 MW / Bit 

Heyden 


Kiel 


Mehrum 


Weisweiler G,H 


Weisweiler D 


Nikola Tesla A 

Serbia / 308.5 MW / Lig 

Kostolac B 

Serbia / 348.5 MW / Lig 

Atikokan 

Canada / 226 MW / Bit 

Altbach 

Germany / 347.5 MW / Bit 

* mills from other suppliers 

20 

Mill Type 

Start-Up / 

Retrofit 

N 200 1970 / 1998 Retrofit of classifier 

E * 1978 / 1998 Retrofit of classifier 

MPS 170 1987 / 1998 

MPS 170 1982 / 1998 

MPS 150 1970 / 1999 

Retrofit Measure aim of Retrofit 

Replacement of classifier, 

sealing system, modification of pf ducts 

Replacement of classifier 

Retrofit of mill 



NV 32 1962 / 2000 New design of classifier 

Increase of grinding fineness 

Reduction of temperature 


Reduction of unburnt low NO X firing 


Reduction of unburnt low NO X firing 


Reduction of unburnt 

Coal change, capacity increase 


Reduction of unburnt 

Mill capacity increase 


Lifetime extension of wear parts 

DGS 90 1973 / 2000 New rotor, RPM increase Mill capacity increase 

MPS 235 1976 / 2002 

Adjust. grinding force, 

modification of classifier outlet 


N * 1962 / 2002 Retrofit of classifier Mill capacity increase 

MPS 235 1992 / 2003 Retrofit of mill parts Conversion to biomass fuel 

MPS 255 1987 / 2005 

Adjust. grinding force, RPM increase, 

modification of pf ducts 


MPS 180 1970 / 2005 Retrofit of dynamic classifier Mill capacity increase 

MPS 190 

DGS 130 

1979 / 

2008 / 11 

1974 / 75 / 

2008 


(static to dynamic) 

Mill capacity incrase 


Retrofit of mill parts Mill capacity increase 

N 80.75 * 1965 / 2008 Retrofit of mill parts Mill capacity increase 

DGS 100 

N 275.45 * 

MPS 190 

(75 inch) 

1976 / 

2010 / 11 / 12 

1991 / 

2010 / 12 

Redesign of mill parts new rotor, 

RPM increase 

New design of classifier 




“Low NO X ready” 



1985 / 2012 Redesign – engineering of mill parts Conversion to biomass fuel 

MPS 150 1997 / 2012 RPM increase, new nozzle ring 


Reduction of pressure loss

Firing Rehabilitations with HPE Burners – Extract 

Power Plant 

Country / MW 

Sostanj III 

Slovenia / 275 MW 

Niederaußem B 

Germany / 150 MW 

Niederaußem A 


EDF Vitry 3 

France / 250 MW 

EDF Vitry 4 

France / 250 MW 

Ontario Power, Nanticoke Unit 2 + 4 

Canada / 500 MW 

Cascades Arnsberg, Unit 1 

Germany / 60 t / h 

Heyden P.S. 


Ljubljana Boiler 3 

Slovenia / 50 MW-CHP 

Neurath A 


Neurath B 


Cascades Arnsberg, Unit 2 


Ontario Power, Nanticoke Unit 1 


GKW Kiel 


Niederaußem, Unit C1 / C2 


GKW Hannover, Boiler 1+ 2 


Stockstadt, Boiler 9 


Wilhelmshaven 


Weiher P.S. 


Eshkol C, Boiler 6 + 7 

Israel / 230 MW 

Sostanj IV, Unit 5 

Slovenia / 345 MW 

Eshkol D, Boiler 8 + 9 

Israel / 230 MW 

Ontario Power, Nanticoke Unit 5 


Narcea 

Spain / 350 MW 

La Robla 

Spain / 350 MW 

TENT A5 

Serbia / 308.5 MW 

La Cygne – Kansas 

USA / 715 MW 

burner 

Type 

Fuel Kind of firing 

no. of 

burners 

burner 

load MW th 

year of 

Commissioning 

RS ® Lignite Tangential 4 31 1994 



DS ® Bituminous Front 24 35 1998 


DS ® Bituminous Opposite 80 35 1999 

DS ® Semi-anthracite Opposite 8 6 1999 





DS ® Semi-anthracite Opposite 8 6 2000 



RS ® Lignite Roof 2 x 6 76 2001 





ADS 

Heavy fuel oil, 

natural gas 

Opposite 2 x 16 40 2002 


ADS 

Heavy fuel oil, 

natural gas 

Opposite 2 x 16 40 2003 

DS ® Sub-bituminous Opposite 40 35 2006 

DS ® Anthracite Roof 24 36 2006 

DS ® Semi-anthracite Roof 24 36 2007 


DS ® Sub-bituminous Opposite 56 35 2012 


Inspire the Next 

22


Hitachi Power Europe GmbH 

Schifferstraße 80 

47059 Duisburg, Germany 

Phone +49.203.8038-0 

Fax +49.203.8038-1809 

infobox@hitachi-power.com 

www.hitachi-power.com 

© Hitachi Power Europe GmbH / 06.2012 / Printed on chlorine-free bleached paper

Modernization - Hitachi Power Europe GmbH

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