Hydrogen is a solution to significantly reduce CO2 emissions from the combustion of a glass melting furnace, with the use of green hydrogen avoiding them altogether. Hrastnik1860 and SORG had worked on a laboratory and pilot scale to test the use of hydrogen for glass production.
SORG has already tested various burner types, and newly developed gas-oxygen and underport burners (SDB) are being prepared on an industrial scale. The SORG SDB underport burner has been operated with 100 percent H2 in the GWI Hy-Glass project, while another test with a natural gas/H2 and LPG/H2 mixture starts in early 2024.
In this industrial style set with Hrastnik1860, the safety measurement, control system and calculation software were designed specifically for hydrogen. Installed on a furnace so that both hydrogen and pure operation with hydrogen or gas can be supplied in normal operating conditions, the existing gas and oxygen supply equipment were utilised in the process chosen by SORG. The H2 supply and control systems meet all applicable standards and regulations, as well as gaining official approval for safety.
During December 2023, the oxyfuel-powered glass production plant of Hrastnik1860 was switched from gas to hydrogen. Individual burner pairs were gradually switched to hydrogen and the hydrogen content in the gas was gradually increased. Gas content was reduced to an energy equivalent and the oxygen was adapted to the lower oxygen demand. Only the H2 volume percentage was set on the control system, with all heating parameters calculated and controlled automatically. The burners were operated with hydrogen for several days. A second test switched the melting furnace burners directly from 100 percent natural gas to 100 percent hydrogen.
This trial shows the possibility of switching to hydrogen with the appropriate system technology and control. The results show that it’s relatively easy to switch and revert a furnace to hydrogen by adapting the heating system to the different physical properties of gas and hydrogen. Operational changes were also within the expected range and controllable.