Back to search

ENERGIX-Stort program energi

Energy Efficiency for Al Casthouse Furnaces

Alternative title: Energieffektivitet av aluminium smelteovner

Awarded: NOK 7.7 mill.

Project Number:

310061

Project Period:

2020 - 2024

Funding received from:

FurnAl is a 4-year project that started May 1st, 2020, aiming at the development and implementation of high efficiency Aluminium melting and holding furnaces. It is a collaboration between Hydro Aluminium AS, Linde Gas AS, NEO Monitors AS and the R&D institute SINTEF. The aim of the FurnAl project is to develop and implement a furnace energy efficiency strategy for current and future solutions in Hydro's casthouses. This should facilitate 10 - 20 % improvement in the energy efficiency for the best benchmark furnaces. This will be done by addressing all important factors influencing the furnace energy efficiency. For different furnaces there are large variations in the energy efficiency, over time for each furnace and between the different furnaces. By better understanding and controlling these variations, the potential for reduction in fuel consumption, cost and CO2-emissions might be realized. FurnAl will therefore develop numerical models for better understanding and assessment of new and improved technologies and operations, and development of a digital twin coupled with in situ monitoring in the furnace, for early warning of wrong furnace behaviour and initiation of correcting maintenance procedures. In 2020, a Failure Mode, Effects, and Criticality Analysis (FMECA) with respect to energy efficiency and consumption was done for furnaces and burners. In 2020, evaluation of data from about 20 of Hydro's melting furnaces was also started to identify important factors for the energy efficiency of the furnaces. In 2021, additional parameters have been included to make a best possible mapping and ranking of the factors of importance for the energy efficiency of the furnaces. FurnAl has two pilot melting furnaces, one in Årdal and one in Sunndal. In 2020, work to establish a detailed model for the pilot furnace in Årdal was started. In 2021, studies and validation of this model have continued. In addition, a detailed model for the pilot furnace in Sunndal has been made. Measured data from the exhaust from a melting furnace can give important information about the behaviour of the furnace with respect to combustion and cold, false air from the outside, two important factors that influence the energy efficiency of the furnace. Towards the end of 2020, Hydro installed an O2 sensor from Linde Gas in the pilot furnace in Årdal. In 2021, NEO Monitors has installed sensors for O2, CO2, H2O, and temperature in the stack in the pilot furnace in Sunndal. Ferronva, one of Linde Gas' departments in Sweden, has also completed a measurement campaign in the pilot plant in Årdal, where data for the same gasses and the temperature have been measured. Because of the covid-19 situation in 2021, the installation of sensors in Sunndal and the measurement campaign in Årdal were done in the fall 2021, after the vaccination and the reopening. After the installation, the sensors from NEO Monitors are logging data continuously from the furnace in Sunndal. These data will be used for monitoring of the furnace. The new data from Årdal and Sunndal will also be used for further validation of the detailed models for the two furnaces.

Hydro Aluminium has a total of 27 melting and holding aluminium furnaces located in 5 different casthouses in Norway. Surveys of fuel consumption and energy efficiency for the different furnaces show large variations. The main objective of this R&D project is to develop numerical models and monitoring techniques for casthouse furnaces for improved the energy efficiency. This involve detailed modelling of the furnace process, and development of a 'digital twin', coupled with monitoring of the furnace, for early warning of wrong furnace behaviour and initiation of correct maintenance procedure. The detailed models will be used to achieve better understanding about the root causes and mechanisms for the large variations in energy efficiency for the different furnaces. The planned control system for furnace maintenance (a 'maintenance predictor') in terms of a digital twin, will describes the true state of the furnace regarding faulty behaviour such as infiltration of cold air or poor combustion, and alert when maintenance is needed. The maintenance predictor will utilise real time monitored data for combustion gases, CO2, CO, O2, temperature and pressure in the furnace. The project will therefore develop schemes for online monitoring of combustion gases, temperature and pressure in the furnace. The project will enable Hydro to achieve 10 – 20 % improvement in the energy efficiency for the best benchmark furnaces with cold air or oxy-fuel burners.

Funding scheme:

ENERGIX-Stort program energi