ENGINEERING

Cokeless Cupola Furnaces

Economical and environmentally melting plants

Development · Planning · Realization

Cokeless cupola furnaces from Düker – over 500 years of experience in iron casting

The name Düker has stood for top quality iron cast- ing for more than 500 years. Today we are one of the leading manufacturers of fittings, pressure pipe fittings for drinking water and gas supplies and of pipes and fittings for drainage technology.

We also manufacture highly resistant enamelled components and pipes for the chemical and pharmaceutical industries. Another production field of our business is job castings where we act as a contract manufacturer for parts for the printing, automotive and mechanical engineering industries.

Our own cokeless cupola at our plant in Karlstadt

Düker Engineering – worldwide service A comparison of melting furnaces

Service

Consultancy Cokeless cupolas

from Düker

Planning

With this background of immense experience, we also plan and build complete centrifugal casting plants, cokeless cupola furnaces and control systems for manufacturing business all over the world.

Each of these systems has its own individual design which depends on the site conditions and the specific requirements of the customer.

Since we have also been using our systems for many years for our own production operation, our customers have a unique range of expertise at their disposal, which is constantly being updated and

extended.

When planning a melting operating, at some stage the question of the type of melting furnace to be installed will be raised. In principle there are two different processes to choose from: Cupola furnaces and electric melting furnaces.

Cupolas melt pig iron, defective castings and steel scrap and use coke, min- eral oil or natural gas as fuel. They are the preferred continuous melting units for iron foundries since they can supply high quantities in constant quality. As the name suggests, electric furnaces use electricity to power them and are used for discontinuous applications with frequent analysis changes.

Certified quality:

We received certification to DIN EN ISO 9001 way back in 1993. Since then our quality man-

Training

Installation

Implementation/

Design We thereby offer our customers worldwide a convenient and

customized all-round service which is virtually unique – from the design, planning and construction to assembly, commissioning

and training your personnel – you receive everything from a single

agement system has been updated and im- proved on an on-going basis by means of regu- lar inspections and also internal and external audits.

source.

2 3

Cokeless cupolas from Düker – economical and environmental

4 5

HW cupola liningless

KW cupola secondary wind and O2

Cokeless cupola, gas-fired with superheater

KW cupola HW-Lz cupola liningless

KW cupola, secondary wind or O2

HW-Lz cupola with lining

KW cupola, secondary wind and O2

HW cupola, without material cool- ing, daily alternating operating mode

Cokeless cupola, KW + O2 , electric superheating

Carburisation %/t 1,1

Si-blanks %/t 0,8

Ceramic spheres %/t 0,95

Slag-forming constituent %/t 0,3

Cokeless cupolas ideally use natural gas as fuel. This gives them a better heat balance and con-

Energy consumption in MJ

Convincing benefits Operating costs for melting GJS base iron in cokeless cupolas

siderably better emission values.

Overall this results in a whole series of major ben- efits compared to alternative furnace systems such as coke-fired cupolas.

1525 °C tapping temp./ 1 ton liqud iron GJS

4975

3926

2443

1000

Charging • expensive coke stores not required Melting

• the melting process is easier to control with natural gas

• less slag formation • cleaner primary energy • constant tapping temperature with flexible output • the melting process can be interrupted without

any problem

Energy Unit Consumption/t GJS 1.1 Natural gas consumption

Preheating the furnace m3 600

Melting m3 48 - 52

1.2 Electrical energy consumption

a.) Superheater KWh

Superheating KWh 64,0

Keeping warm KWh 15,0

b.) Auxiliary mode KWh 25,0 Energy use for melting in cupolas in %

1500 °C cupola tapping temp. 70

60

50

40

30

20

10

KW = Cold wind HW = Hot wind Hw-Lz = Hot wind for long term campaign O2 = Oxygen

Environmental balance of the cokeless, natural gas-fired cupola

Superheater • low use of additional electrical energy required • accurate carburisation • base iron does not have to be desulphurised Quality • uniform analysis is possible • excellent flow properties of the molten metal • very low volumes of transition iron • ideal melting losses for C, Si and Mn • no sulphur pick-up Economy

• low purchase cost for new systems • simple conversion of existing cupolas • low costs for dust extraction • perfect energy use with duplex system

1.3 Refractory consumption

Shaft-blast furnace kg 5 - 8

Siphon kg 0,7

Superheater kg 0,5

1.4 Water consumption m3 0,4

1.5 Oxygen m3 19,7

1.6 Metallic charging

Steel %/t 25 - 35

Pig iron %/t 20 - 30

Returns %/t 35 - 55

1.7 Alloy-materials/Additives

Energy use MJ/ T Fe Carbon dioxide emissions kg/ T Fe Sulphur dioxide emissions kg/ T Fe Environment

4500 4000

450 2,5 400

Coke cupola • no air pollution with sulphur compounds 3500 3000 2500 2000 1500 1000 500

350 300

250 200

150 100 50

2,0

1,5

1,0

0,5

Cokeless cupola

• low level of pollutants in the slag • no CaC2 slag from GJS production • reduced nuisance emissions • low duct content in the flue gas

Cokeless cupolas from Düker – added value that pays dividends every day

6 7

GJL GJS GJL GJS

Return (kg) 400 400

Cast iron scrap (kg) 400

Steel scrap (kg) 200 350

Pig iron (kg) 250

Slag-forming constituents (kg) 35 30

Consumption of natural gas (m3) 50 50

Consumption of ceramic spheres (kg) 9,5 9,5

Consumption of refractory materials (kg) 9 9

Consumption of water (m3) 0,4 0,4

Consumption of electricity (KWh)

3

80

500

80

500

Flue gas (m3) 600 600

This is how a cokeless cupola works

First of all the grating in the furnace is covered with ceramic spheres. Then the preheating phase begins which takes around 45 minutes. After this the cokeless cupola is fed with metallic charge materials and slag-forming constituents.

The hot combustion gases from the gas burners flow through the ceramic sphere bed and inten- sively heat the charge material. This melts and flows on to the ceramic spheres. Thereby it is su- perheated and drips into the bottom of the furnace. Slag and iron are finally separated from each other in the furnace’s siphon.

Just 15 minutes after the first furnace charge has been inserted, the first iron will flow into the elec- trically heated superheater where the required temperature and alloy are adjusted.

The furnace gas generated by the melting process is continuously exhausted, cooled and purified by dry filters in the top section of the furnace in a gas/air exchanger.

Charge material Shaft cooling system Blast pipe Ceramic sphere bed Water-cooled grid

Gas burner Siphon Superheater Inductor

Charging and operating data of the cokeless cupola

Combustion air (m ) All figures are relative to one ton of cast iron Analysis of the production of GJL/GJS

C Si Mn P S

GJL cupola tapped iron 1400 - 1420 °C 2,8 1,8 0,4 0,06 0,03

GJL liquid iron 1480 °C at superheater 3,3 2,3 0,6 0,06 0,03

GJS cupola tapped iron 1400 - 1410 °C 2,6 1,6 0,2 0,04 0,09

GJS liquid iron 1520 °C at superheater 3,7 1,6 0,2 0,04 0,09 Figures in % Modernisation of existing cupolas We can convert existing cupolas which can still use as a fuel to gas opera- tion without any problems. In this respect we also will inspect your furnace thoroughly to establish its efficiency and function. It is of no consequence to us whether it is one of our systems or was supplied by another manufac- turer. Which of the various possible solutions ultimately makes sense will be determined individually for each customer.

Control equipment made by Düker

With our process control systems you can con- trol all the parameters for your cupola and the periphery conveniently from your PC.

A clear visualisation system shows you all the characteristic data permanently and you can then adjust them and save them if necessary. This ensures the uniform high quality of the melting process.

We actually make our control systems at our plant in Karlstadt, Germany. They undergo ongoing de- velopment and improvements. This means that our customers can rely on the fact that they will always have the very latest technology

– for years to come. Training and maintenance Naturally we are also available for you after the commissioning procedure for your new or modern- ised cupola furnace. For example we can provide training courses and advanced training for your personnel, keep your system working cor- rectly with regular service and maintenance work and also keep you up to date with possible modernisation options.

ENGINEERING

GLASS LINING TECHNOLOGIES

JObbING FOUNDRy

FITTINGS AND vALvES

DRAINAGE TECHNOLOGy

10.09 Subject to technical changes and printing errors.

Düker GmbH & Co. KGaA

Würzburger Straße 10 D-97753 Karlstadt /Main

Phone +49 9353 791-235 Fax +49 9353 791-175

Internet: www.dueker.de E-Mail: info.engineering@dueker.de

Kuttner North America 211 N. Franklin Street, PO Box 343

Port Washington, WI 53074

Phone +1 262 284 4483 Fax +1 262 284 4483

www.KuttnerNA.com CokelessCupolas@KuttnerNA.com