The markets for lithium-ion batteries, electric vehicles, and fuel cells are increasing exponentially, meaning the demand for graphite is higher than ever before. Lithium-ion batteries consist of four components: electrolyte, separator, cathode, and anode. Every component is essential to the battery, meaning it cannot function without one. Graphite is the single largest mineral component of the battery, making it an essential material in manufacturing lithium-ion batteries and electric vehicles that rely on batteries.
The anode stores lithium ions when the battery is being charged and then releases them, allowing currents to pass through an external circuit. Graphite powder is currently the most-used anode material due to its composition and storage capacity.
With no common alternative to graphite, graphite mining has become more essential. Mining natural graphite offers lower carbon emissions than the energy-intensive production of synthetic graphite. New companies are being formed and existing companies are ramping up production by creating new mines and production lines. However, more mining activity leads to more emissions and a greater carbon footprint for these companies.
Anguil Environmental Systems recently helped lower carbon emissions from the production of battery material with the installation of air pollution control equipment at a natural graphite mine in Canada. Increased government regulation on emissions and the desire to create a sustainable product motivated this company to install a custom-designed system from Anguil.
Increasing government regulations on emissions often drives companies to install air pollution control equipment. However, more companies are being motivated by ESGs, or Environmental, Social, Governance, which is an assessment of a company’s ability to limit its environmental and social impact. This graphite mining company is ahead of many, as they have already achieved carbon neutrality and are hoping to be Net Zero by 2030. So, when installing new production lines, it was no question that they were going to install pollution control equipment.
This specific plant produces high-quality Coated Spherical Purified Graphite (CSPG) for lithium-ion battery anodes. Due to the unique nature of their process, Anguil recommended a demonstration line, or pilot unit, to prove system effectiveness and efficiency for the specific graphite qualities at the processing plant. The emissions to be treated were from a pusher furnace/kiln that processed graphite and pitch. The furnace exhaust was inert (no oxygen) and at a high temperature, with the possibility of condensable organics. The furnace hood exhausts, which would contain oxygen and trace VOCs, also needed to be sent to the oxidizer. This meant Anguil’s engineers had to ensure good mixing of the two process streams with an additional third fresh air stream to be added to ensure the proper oxygen needed for oxidation. The equipment selected was a 500 SCFM (790 Nm3/h) Direct Fired Thermal Oxidizer (DFTO), which is capable of over 99.5% VOC destruction efficiency. The DFTO was coupled with a proprietary inlet mixer to alleviate the mixing and condensation concerns. The mixer was designed to minimize cold spots when the air streams were introduced to the process stream.
Anguil utilized CFD modeling to ensure the proposed design would have proper mixing and flow distribution to maintain emission destruction requirements and efficiency parameters.
An increased residence time in the combustion chamber was also added to meet destruction requirements. A horizontal combustion chamber allowed for the system to be installed above the furnace inside the facility. An induced draft configuration was incorporated to keep the oxidizer system operating under negative pressure for health and safety concerns. Anguil worked closely with the furnace supplier to ensure a seamless integration.
The plant runs on renewable electric hydropower, which meant the energy use of the equipment had to be minimal. The DFTO operates on propane that is used for the initial equipment startup, and to maintain a pilot flame only. The high VOC content in the process means that little to no supplement fuel is needed to keep the oxidizer at operating temperature during normal operation. This results in essentially no additional greenhouse gas emissions to reach their goal of carbon neutrality. The burner will be operating on pilot flame only during normal production and the DFTO controls allow the oxidizer to automatically adjust to changing inlet conditions to ensure the minimum amount of supplemental fuel is used. Anguil is working on a lower carbon footprint oxidizer for the future full-scale production lines that will be implemented at this site. The new design will eliminate the carbon dioxide formed from a typical gas-fired burner. Despite facing obstacles due to COVID-19, Anguil was able to install a high-quality system and offer professional support during the installation and commissioning stage. Anguil’s extensive network of service engineers was able to overcome the difficulties of travel during the COVID lockdown period.
As the company gears up to create full-scale production lines, the Anguil air pollution equipment will keep emissions below government regulations. Anguil technology can be adapted to meet customers’ energy needs and help them transition to even lower carbon footprint-oxidizers in the future.