Increasing of the resources-efficiency by experimental optimisation of steam production and by reduction of production residues in a metal-processing factory

The project is based on the results of the currently running project "Use of waste heat and renewable energy sources in a metal-processing factory". In this project it was found, that nearly the half of the consumption of natural gas is needed for steam production. Based on calculations already carried out, it is planned to investigate experimentally the possibilities of increasing the resource-efficiency by lowering the steam temperature and by replacing steam by hot water. Further increasing of resource-efficiency shall be achieved by use of internal residues as an additional fuel in a solid fuel furnace.

Short Description



Aims of the project

Joh. Pengg AG with headquarters at Thörl in Styria, is specialized in production of oil tempered spring wires for automobile-, electrical, and mechanical engineering industry. Production of such wires is an energy intensive process with several heating, cooling, and shaping production steps. The subject project was based on the results of a previous study, which showed, that a major part of natural gas is used to produce steam at a high temperature level, although most of the process heat is needed at a lower temperature level. The first goal of the subject project therefore was the

  • reduction of the fuel input for steam production
    by reducing temperature/pressure of the steam. Investigations about the possibility to reduce these parameters and to replace steam by hot water without reducing the quality of the wires have been carried out.

The second goal of the subject project was

  • increasing the efficiency of energy conversion by using production residues as fuel.
    Investigations to replace (totally or partially) the currently used natural gas boilers by biomass boilers have been carried out. The fuel should be industrial wood chips together with production residues. Beside the benefits of the thermal utilization of the residues, also the avoided costs of disposal have been investigated.

Tasks and results

  • Investigations concerning the complete replacement of steam by hot water:
    Result: Replacing of steam by hot water is possible and useful in all process steps.
  • Combustion tests
    Result: Combustion of production residues "soap", "waste paper", "plastic residues" and "industrial waste" together with wood chips, in the given mass relation, is possible without major problems.
  • Chemical analysis of combustion ash
    Results: The chemical analysis of combustion ash, carried out by Foschungsgesellschaft Technischer Umweltschutz, Vienna, showed, that the combustion ash is classed for disposal in a landfill. The disposal costs have minor influence on the economy.
  • Lay out of the biomass boiler
    Several possibilities of using biomass boilers with different heat power levels have been investigated. The most suitable concept from a technical viewpoint is the following:

    Installation of a new (biomass-)boiler und redesign of the heating system of the wire production process inclusive space heating. The fuel power during the winter period is 2.200 kW, the fuel power during the summer period is 363 kW (= 16,5 % partial load). Due to the low partial load, 2 boilers would be necessary (fuel power: 363 kW and 1.873 kW). The heat power of the boilers in this case would be 330 and 1.700 kW.

An economical analysis of this concept has shown the following key results:

  • Investment costs of the 2 biomass boilers: 1,298.000,-- €.
  • Amortisation period respecting fuel costs between 0,08 and 0,14 €/kWh and interest rates between 2 % and 5 %: Between 7,4 und 10,7 years.

Project Partners

Project management

Dipl.-Ing. Dr. Reinhard Padinger
JOANNEUM RESEARCH Forschungsgesellschaft mbH


JOANNEUM RESEARCH Forschungsgesellschaft mbH
Institut für Energieforschung
Elisabethstraße 5, A-8010 Graz
Tel.: +43 (0)316 876-1338
Fax: +43 (0)316 876-1320

Project or cooperation partner

Contact Address

Steyrergasse 17, A-8010 Graz
Tel.: +43 (0)316 876-1333
Fax: +43 (0)316 876-91333