At Libbey, Leerdam, the OPTIMELT furnace, a waste heat recovery process in the glass industry, was visited. By injection of natural gas in the hot flue gases in a regenerator of an oxy-fired glass tableware furnace, high temperature syngas is produced and then burnt in the furnace. The hot syngas mixture has as higher caloric value than natural gas. Around 15% energy saving and corresponding CO2 reduction have been demonstrated to date.
Later that day, at Tata Steel in IJmuiden, a short symposium was organised, followed by a tour of one of the steel factories on the vast premises of Tata Steel. The keynote lecture was presented by Professor Ad van Wijk, sustainable energy entrepreneur and part-time Professor, Future Energy Systems at Delft University of Technology. His message is that at first, ‘blue’ and then ‘green’ hydrogen will become the main energy carrier in a low carbon economy.
Already within about 10 years from now, ‘green’ hydrogen, produced by electrolysis in offshore wind power plants, will become economically competitive with natural gas (see table 1). The key advantages of hydrogen versus electrons as an energy carrier are the efficient storage and transport possibilities of hydrogen, by making use of the existing infrastructure for natural gas (see figure 1) and of available gas storage locations and technologies.
50% CO2 emission reduction
Tata Steel presented a paper on the HIsarna ironmaking process, developed within a large European project, in which many competing steel companies have co-operated. The HIsarna ironmaking process is a direct reduced iron process, in which iron ore is processed almost directly into liquid iron or hot metal. The process does not require the manufacturing of iron ore agglomerates such as pellets, nor the production of coke, which are necessary for the blast furnace process. Without these steps, the HIsarna process is more energy-efficient and has a considerably lower carbon footprint than traditional ironmaking processes. In 2018 Tata Steel announced it has demonstrated that more than 50% CO2 emission reduction is possible with HIsarna technology, without the need for carbon capture technology.
CelSian presented a paper on the transition to CO2 neutral glass furnaces and concluded that a combination of durable hydrogen and electricity from renewable sources will enable the energy transition in the glass industry. In the coming years, co-firing of natural gas with hydrogen may enable a gradual transition to a low-to-zero-carbon combustion process. The technological challenges of hydrogen combustion in glass furnaces were outlined and a new inter-sectoral development project was announced; ‘Hydrogen as fuel for direct industrial heating processes’, with the former Gasunie Research (now DNV-GL) as lead party.
Renewable energy technology
On the second day of the tour, the renewable energy technology and gas laboratory of DNV GL (formerly Gasunie Research) in Groningen was visited. This site has 5000m2 of dedicated gas laboratories. In the 0.5 MW combustion furnace, combustion processes with natural gas-hydrogen mixtures are studied.
The above-mentioned inter-sectoral project proposal was presented by DNV-GL in detail. The main topics of this project will include fuel adaptive burner control systems when using hydrogen/natural gas mixtures, effect of hydrogen on heat transfer and NOx control strategies. CelSian will support the experimental studies by installing the CO+ laser sensor at DNV-GL’s test furnace (figure 3) and by 3D CFD modelling calculations of heat fluxes, temperature profiles etc.
Increased hydrogen supply for ceramics
The final production site visited was the factory of Wienerberger Narvik near Venlo. Wienerberger AG is the world’s largest producer of bricks and number one in the clay roof tile market in Europe. The factory tour showed state-of-the-art production processes for roof tiles, including the application of glazes.
Representative from the Technical Centre for the Ceramic Industry (TCKI) presented a paper on scenarios for future sustainable ceramic kilns by gradually increasing hydrogen supply to the burners. The challenges of energy transition in the ceramic industry include future Wobbe index ‘jumps’ in the combustion gas supply, control of NOx from hot hydrogen-rich flames and control of CO2 originating from the clay raw materials.
Surprisingly, during this 800km GlassTrend round trip across the Netherlands, no geographical borders were crossed. However, all participants will confirm that many mental borders and borders between different industrial sectors were