Startup Carbon Clean announced earlier this week that it raised $150 million in a Series C that provides it with a sizable war chest to continue the development of its modular carbon capture system.
Carbon Clean has won its share of admirers, most recently Chevron, which led the round, and BloombergNEF, which named it a BNEF Pioneer last month in part because of the startup’s small-scale approach to carbon capture and sequestration (CCS).
Typically, the technology is a large-scale affair. After all, the world needs to eliminate emissions on a vast scale, and the technology benefits from a certain amount of scale. That’s why CCS is usually envisioned attached to massive coal- or gas-fired power plants.
But there are still many smaller sites, from cement kilns to chemical plants, that are currently wedded to fossil fuels but still need to be decarbonized. These are the sorts of companies that Carbon Clean pitches itself to, and the startup says that its modular approach can help polluters deal with their carbon emissions incrementally as regulations ratchet up.
Fundamentally, Carbon Clean relies on a tried-and-true process to strip carbon dioxide from exhaust streams. Exhaust containing carbon dioxide is sent through a filter that is wetted with an amine-based solvent. At lower temperatures (around 50 degrees Celsius, or 122 degrees Fahrenheit), carbon dioxide will bind to the amines. The CO2-laden solvent is then pumped to another container, where it’s heated to 110 to 120 degrees C (230 to 248 degrees F) to release the gas, which is then compressed and sent elsewhere to be used or stored. Each company has its own amine solvent with different properties, and the details of the process may vary, but that’s the gist of it.
Carbon Clean CEO Aniruddha Sharma said his company’s amine solvents can reduce costs compared with a commonly used amine by requiring less energy to heat and by reducing corrosion in the system. Until the company releases more data, such claims will be hard to judge. But based on the general type of amine it’s using, Carbon Clean is likely to see at least a small improvement in energy use.