Research on Hydrogen Energy Application in Glass Production Lines
Introduction
In glass production, fossil fuels such as natural gas or heavy oil are typically used as the primary energy sources, accounting for over 60% of total carbon dioxide emissions. However, with increasing attention to environmental sustainability and the growing demand for clean energy, hydrogen has garnered significant interest as a potential alternative energy source for glass furnaces. Hydrogen is a clean energy source, and its use in glass furnaces can significantly reduce carbon emissions, contributing to climate change mitigation. Additionally, hydrogen has a high calorific value per unit mass, enabling higher combustion efficiency and thereby improving energy utilization efficiency in glass production.
1. Current Research Status of Hydrogen Energy Application in the Glass Industry
To address the energy crisis and achieve carbon neutrality, the global energy structure is continuously evolving, with a growing focus on clean and renewable green energy. As a critical component of the new energy system, “hydrogen energy” is hailed as the “ultimate energy source of the 21st century.” It offers advantages such as abundant reserves, lightweight properties, high combustion calorific value, and pollution-free byproducts. Hydrogen can be produced through electrolysis of water using electricity generated from renewable sources like wind and solar energy, making the entire production process pollution-free. To achieve energy conservation and emission reduction, the glass industry has prioritized hydrogen energy utilization.
China is the world’s largest producer and consumer of hydrogen energy, with a complete hydrogen industry chain encompassing production, storage, transportation, refueling, and application. The glass manufacturing process is characterized by high energy consumption and pollution emissions. Replacing fossil fuels such as natural gas or oil with hydrogen can significantly reduce greenhouse gas emissions, making it a key development direction for lowering carbon emissions in the glass industry. Currently, numerous glass-related companies worldwide are conducting research in this area. The glass industry consumes approximately 1.0 × 10^18 J of hydrogen annually.
In 2021, Pilkington UK achieved the production of flat glass using 100% hydrogen for the first time at its factory in St Helens, UK.
In the same year, Schott collaborated with Germany’s largest energy transition research project, “Copernicus Project,” and successfully completed initial tests melting glass with hydrogen.
In 2022, Schott launched a pilot project at its headquarters in Mainz, Germany, using a mixture of hydrogen and natural gas for large-scale glass production.
In 2023, Bacardi partnered with premium glass manufacturer Hrastnik 1860 to innovate glass furnace technology using hydrogen as the primary energy source. The trial-produced liquor bottles maintained identical appearance to those produced by traditional methods. During the trial, hydrogen provided over 60% of the furnace fuel, reducing greenhouse gas emissions by more than 30%.
In 2024, Schott successfully achieved 100% hydrogen energy melting of optical glass through innovative technological changes, making the industrial application of green hydrogen possible.
2. Application of Hydrogen-Blended Natural Gas in Glass Furnaces
By using natural gas-hydrogen blending equipment, natural gas and hydrogen are thoroughly and uniformly mixed. The mixed gas is then delivered to the 0# oxygen lance system for efficient combustion. This approach uses hydrogen as a partial alternative energy source to reduce natural gas consumption and increase the proportion of clean energy in the energy structure.
(1) Design of Natural Gas-Hydrogen Blending Equipment
To achieve the mixed application of natural gas and hydrogen, a series of optimizations and improvements to existing natural gas equipment are necessary. A hydrogen delivery pipeline system has been added to safely and efficiently introduce hydrogen into the natural gas supply system. The hydrogen pipeline is made of stainless steel to withstand the unique physical and chemical properties of hydrogen, ensuring safety and stability throughout the delivery process. Additionally, a natural gas-hydrogen mixing device has been installed to ensure thorough and uniform mixing of the two gases. The design of the mixing device considers factors such as the mixing ratio, uniformity, and the properties of the mixed gas to ensure the final output meets combustion equipment requirements while achieving energy conservation and emission reduction goals. The natural gas-hydrogen blending equipment is shown in Figure 1.
(2) Changes in Combustion Flame Before and After Hydrogen Blending
By increasing the hydrogen flow rate from 0 Nm³/h to 60 Nm³/h while keeping the natural gas flow rate constant, changes in flame length were recorded via observation panels, as shown in Figure 2.
Figure 1: Natural Gas-Hydrogen Blending Equipment
Figure 2: Changes in Combustion Flame Before and After Hydrogen Blending
Figure 2 clearly shows that when the hydrogen flow rate is 0 Nm³/h, the flame appears relatively dispersed and elongated. When the hydrogen flow rate increases to 60 Nm³/h, the flame becomes more concentrated and shorter. The high combustion speed of hydrogen accelerates gas flow within the combustion zone, sharpening the flame front and reducing the overall flame length. It also promotes local turbulence in the combustion zone, further enhancing heat and mass transfer during combustion, making the process more efficient and thorough. This change not only validates hydrogen’s combustion characteristics but also provides experimental basis for further optimizing combustion efficiency.
(3) Changes in Furnace Temperature
The quality of glass products largely depends on the melting temperature and duration. Precisely controlling the temperature of the glass furnace ensures uniform melting of the glass liquid, reducing bubbles and impurities, thereby improving product quality. Temperature can be controlled by setting parameters such as fuel supply and air supply. The initial melting temperature of glass liquid is typically around 1400°C, but in actual production, to eliminate bubbles, the maximum melting temperature in float glass furnaces can reach 1580–1600°C.
To study the impact of hydrogen-blended combustion on furnace temperature, temperature changes before and after hydrogen blending were tested. Detailed records were made of temperature changes at key points (e.g., castables, wall bricks) in the furnace crown under different hydrogen flow rates, as shown in Table 1.
Table 1 indicates that compared to no hydrogen blending, when hydrogen flow rates are 30 Nm³/h and 60 Nm³/h, temperatures at various points in the furnace slightly increase. This is primarily because hydrogen has a higher calorific value than natural gas. After hydrogen blending, the calorific value of the mixed gas increases, leading to a rise in furnace temperature. Additionally, when the hydrogen flow rate is stabilized at 30 Nm³/h and 60 Nm³/h, no significant fluctuations are observed at various points in the furnace over different time periods. This indicates that at these flow rates, hydrogen blending has a protective effect on the stability and uniformity of furnace temperatures. Figure 3 shows the temperature changes at the crown of 1# small furnace under different hydrogen flow rates.
Figure 3: Temperature Changes at the Crown of 1# Small Furnace Under Different Hydrogen Flow Rates
Figure 3 shows that after hydrogen blending, the temperature at the crown of 1# small furnace does not change significantly, indicating that hydrogen-blended combustion has no adverse effects on the furnace.
(4) Changes in Flue Gas Emissions
The primary byproduct of hydrogen combustion is water. To explore the impact of hydrogen-blended combustion on flue gas emissions from glass furnaces, emissions of sulfur dioxide (SO₂), nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO₂) were measured at 1# small furnace, 2# small furnace, and the main flue. The results are shown in Table 2.
Table 2: Flue Gas Emissions Before and After Hydrogen Blending
Table 2 shows that after hydrogen blending, emissions of NOx, CO, and CO₂ are reduced, and the total flue gas emissions also decrease. This indicates that hydrogen blending not only reduces the emission burden of individual combustion systems but also positively impacts the overall emission performance of the combustion system.
3. Conclusion
The application of hydrogen energy in glass furnaces not only enhances production efficiency and product quality but also provides strong support for achieving low-carbon economy and sustainable development goals. In the future, with continuous technological advancements and ongoing policy support, hydrogen energy will play an increasingly important role in the glass industry, guiding it toward a greener, more efficient, and sustainable direction.
