Solvent Degradation and Emissions from a 0.7MWe Pilot CO\u3csub\u3e2\u3c/sub\u3e Capture System with Two-Stage Stripping

The UKy-CAER team successfully tested an advanced 0.7 MWe post-combustion CO2 capture system on a coal-fired power plant using a heat integration process combined with two-stage stripping to enhance the CO2 absorber performance. One of the unique feature of the UKy-CAER integrated process is a two-stage stripping unit for solvent regeneration. The secondary stripper is empowered by the heat rejection from a conventional steam-heated (primary) stripper. The secondary stripper outlet stream at the commercial scale can be used as boiler secondary combustion air, consequently enriching the flue gas with CO2, resulting in less energy penalty required by the CO2 capture system. The primary goal of this study was to form an initial assessment of the impact on the amine solvent from coal combustion flue gas contaminants and the potential higher oxygen content in the solvent due to incorporation of the secondary air stripper into the conventional amine scrubber/stripper system. The overall oxidative degradation was comparable to previous reports with 30 wt% MEA solvent at similar flue gas run hours. This suggests that the addition of the secondary air stripper appears to be negligible with regards to solvent oxidation

Application of a Small Unmanned Aerial System to Measure Ammonia Emissions from a Pilot Amine-CO\u3csub\u3e2\u3c/sub\u3e Capture System

The quantification of atmospheric gases with small unmanned aerial systems (sUAS) is expanding the ability to safely perform environmental monitoring tasks and quickly evaluate the impact of technologies. In this work, a calibrated sUAS is used to quantify the emissions of ammonia (NH3) gas from the exit stack a 0.1 MWth pilot-scale carbon capture system (CCS) employing a 5 M monoethanolamine (MEA) solvent to scrub CO2 from coal combustion flue gas. A comparison of the results using the sUAS against the ion chromatography technique with the EPA CTM-027 method for the standard emission sampling of NH3 shows good agreement. Therefore, the work demonstrates the usefulness of sUAS as an alternative method of emission measurement, supporting its application in lieu of traditional sampling techniques to collect real time emission data

Application of a Small Unmanned Aerial System to Measure Ammonia Emissions from a Pilot Amine-CO2 Capture System

The quantification of atmospheric gases with small unmanned aerial systems (sUAS) is expanding the ability to safely perform environmental monitoring tasks and quickly evaluate the impact of technologies. In this work, a calibrated sUAS is used to quantify the emissions of ammonia (NH3) gas from the exit stack a 0.1 MWth pilot-scale carbon capture system (CCS) employing a 5 M monoethanolamine (MEA) solvent to scrub CO2 from coal combustion flue gas. A comparison of the results using the sUAS against the ion chromatography technique with the EPA CTM-027 method for the standard emission sampling of NH3 shows good agreement. Therefore, the work demonstrates the usefulness of sUAS as an alternative method of emission measurement, supporting its application in lieu of traditional sampling techniques to collect real time emission data

Electrochemical CO2 conversion to formic acid using engineered enzymatic catalysts in a batch reactor

Formic acid is one of the most valuable fuel products for the capture and conversion of CO2 due to its unique usage in fuel cells and hydrogen storage. Electrochemically mediated conversion of CO2 to FA has its advantages over the traditional Kemira process, in that high temperatures and pressures are not required, cutting on manufacturing and operating costs. However, selectivity of the metal catalysts used in CO2 conversion to certain products remains limited. Here, an engineered enzymatic catalyst is employed to convert CO2 into formic acid (in the form of formate) in a batch reactor. This work seeks to maximize both formate production and Coulombic efficiency, which is achieved primarily through: (1) adjustment of the operating voltage, (2) implementation of an O2 scavenger to mitigate competition with dissolved O2, and (3) control of system pH to maintain a stable operating range for the catalyst. Peak formate production and peak efficiency achieved in long-term experiments (> 40 h) were 225 mM and 91 %, respectively, both of which show promise of strong metrics for CO2 conversion to formate. The optimal operating cathode voltage was shown to be below the baseline voltage of ??? 0.75 V vs. Ag/AgCl. In short-term experiments (??? 1 h), operating below this range, at approximately ??? 0.85 V, could achieve efficiencies of 100 %. By implementing sodium thiosulfate as an O2 scavenger, the rate of formate production improved by over 4 ??. Long-term retention of the efficiency, however, remains an issue to be addressed due to the enzyme sensitivity to pH and increased current at higher values of acid used on the anode