Study on biochar and silicon co-production technology of rice husk based on the new ammonia CO2 capture method and its comprehensive benefits

Abstract

Biomass energy coupling with CO2 capture-utilization-storage (BECCUS) technology has been confirmed essential for achieving net-zero CO2 emissions. A new co-generation technology for producing porous biochar and nano silica from rice husk, with KOH and K2CO3 as silica solubilizers, based on the new ammonia-based CO2 capture method is innovatively proposed, whose energy value-economic analysis model is established, and its comprehensive benefits are further investigated. The results of the energy value analysis show that the BECCU technology is environmentally friendly, especially when the reaction reagent is K2CO3, the environmental loading rate is reduced from 1.19 to 0.19, and the sustainability index is increased from 1.40 to 5.32. The economic evaluation results show that it leads to a higher Net Present Value (NPV) and Internal Rate Return (IRR) of the system with solid profitability and self-solvency. While when KOH is selected as the reaction reagent, the NPV increases from 34,253,700 RMB to 119,637,600 RMB, the IRR increases from 40.84% to 59.70%, and its profitability and self-solvency reach the optimum. It provides new ideas for the utilization of biomass energy in low-carbon and multi-production, accompanied by the large-scale consumption and informed utilization of ammonia-based CO2 capture products.