This paper presents a concise overview of ash deposition in combustion or co-firing of biomass (woody biomass, agricultural residues, peat, etc.) with other fuels for power/heat generation. In this article, the following five research aspects on biomass combustion ash deposition are reviewed and discussed: influence of biomass fuel characteristics, deposit-related challenges, ash deposition monitoring and analysis of ash deposits, mechanisms and chemistry of fly ash deposition, and key technologies for reducing ash deposition and corrosion in biomass-involved combustion.

The present work investigates the production of sodium bicarbonate in combination with the co-utilization of saline brine and carbon capture, utilization, and sequestration (CCUS). The use of ammonia in the traditional Solvay process could be eliminated by using a modified Solvay process. This study compared the modification with the addition of three buffering additives: Ca(OH)₂, KOH, and NH₄HCO₃. The effectiveness of these processes, using two qualities of saline brine (desalination and aquifer), is compared based on the purity of the produced NaHCO₃. It was found that the use of Ca(OH)₂ did not produce high-purity NaHCO₃, while NH₄HCO₃ and KOH performed better. Desalination brine utilization with NH₄HCO₃ resulted in the production of high-purity NaHCO₃, while the second most suitable method involved the use of KOH, and the main co-product formed was Na₂CO₃. Geochemical modeling is performed in order to have insights into the carbonation (in the reactor) and precipitation (in the oven) behavior of the reactions. It predicted the precipitation of mineral phases well, though kinetics might hinder some saturated solids to dissolve first. The present study shows that accurate characterization is critical to accurately assess the success of modified Solvay processes. The use of QXRD and SEM analyses, complemented with geochemical modeling, helped to better understand the processes and the formation of NaHCO₃. Further investigations on diverse brines could provide for their better utilization by the geological carbon sequestration and water desalination industries that produce them.

To contribute to the reduction of methane emissions, using low-cost biochar as adsorbents for capturing and storing methane in oil and gas fields is investigated. This work presents results of methane adsorption on four biochars made from forestry wastes in comparison with the results of three commercial activated carbons. Although the adsorption capacity of the biochars is lower by over 50% than that of the activated carbons, thelow-cost and potential environmental benefits provide the incentive to the investigation. Moreover, it is shown that biochar can store more methane than vessels of compressed gas up to the pressure of 75 bar, suggesting the possibility of avoiding high-pressure gas compression and heavy vessels for cost savings in oil and gas fields. The thermodynamic and kinetic behaviors of the adsorption are studied and implications for the targeted application are discussed. Graphical Abstract