Climate Rising Scaling Carbon Capture for Hard-to-abate sectors: Danielle Rapson of Mantel
Oct 1, 2025
Danielle Rapson, Co-founder and COO of Mantle, shares her journey from HBS to pioneering innovative molten-borate carbon capture technology. She explains how Mantle's approach stands out from traditional methods, particularly its efficiency through high-temperature steam reuse. Danielle discusses their projects in the pulp and paper and oil refining sectors, highlighting the impact of policy incentives like 45Q and Canada’s carbon tax. She also delves into the challenges of scaling carbon capture solutions and the growing interest from industries, particularly oil and gas.
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High-Temp Molten Capture Cuts Energy Penalty
- Mantle uses a molten borate to capture CO2 at very high temperatures and recovers that heat as usable steam.
- This reduces the thermal energy penalty from ~2.5 GJ/t to ~0.1 GJ/t, transforming economics for plants that use steam on site.
Steam Reuse Is The Core Efficiency Lever
- By operating absorption/desorption at 400–800°C Mantle recovers heat as ~600°C steam instead of wasting low-grade heat.
- Reusing this steam on site turns a boiler replacement into cost-effective carbon capture.
Designing For Existing Incentives
- Mantle targets costs below current 45Q ($85/t) so projects can be financially viable from tax credits alone.
- They position early commercial projects to generate returns using existing incentives rather than speculative markets.