A critical review on sustainable biochar system through gasification: energy and environmental applications

This review lays great emphasis on production and characteristics of biochar through gasification. Specifically, the physicochemical properties and yield of biochar through the diverse gasification conditions associated with various types of biomass were extensively evaluated. In addition, potential application scenarios of biochar through gasification were explored and their environmental implications were discussed. To qualitatively evaluate biochar sustainability through the gasification process, all gasification products (i.e., syngas and biochar) were evaluated via life cycle assessment (LCA). A concept of balancing syngas and biochar production for an economically and environmentally feasible gasification system was proposed and relevant challenges and solutions were suggested in this review

Bioalcohol production from acidogenic products via a two-step process: A case study of butyric acid to butanol

This article presents the full study (lab-scale experimental study and large-scale techno-economic analysis) results of a two-step catalytic process for the conversion of organic waste–derived butyric acid to butanol. The two-step process consists of the (1) esterification of butyric acid to methyl butyrate and (2) hydrogenolysis of this methyl butyrate to butanol. The first reaction, esterification of butyric acid, was optimized using carbon-based catalysts. The production of butanol from methyl butyrate via hydrogenolysis was investigated using bimetallic Pt–Co catalysts. The hydrogenolysis of methyl butyrate on these catalysts under optimal conditions of 250 °C, 5 MPa H2, and a feed/catalyst weight ratio of 11.2 led to 54.1% selectivity toward 1-butanol. Based on the experimental results, an integrated process simulation model was developed to determine the economic potential of the two-step production of butanol from butyric acid. Using this model, the techno-economic feasibility of the two-step process was analyzed. The minimum selling price (MSP) of 1-butanol produced from butyric acid using this process was US$3.388 per gallon of gasoline equivalent (GGE). This MSP is in the range of recent biofuel market prices of US$ 2.03/GGE to US$ 3.83/GGE

Enhanced catalytic soot oxidation by Ce-based MOF-derived ceria nano-bar with promoted oxygen vacancy

As CeO2 is a useful catalyst for soot elimination, it is important to develop CeO2 with higher contact areas, and reactivities for efficient soot oxidation and catalytic soot oxidation are basically controlled by structures and surface properties of catalysts. Herein, a Ce-Metal organic framework (MOFs) consisting of Ce and benzene-1,3,5-tricarboxylic acid (H3BTC) is employed as the precursor as CeBTC exhibits a unique bar-like high-aspect-ratio morphology, which is then transformed into CeO2 with a nanoscale bar-like configuration. More importantly, this CeO2 nanobar (CeONB) possesses porou, and even hollow structures, as well as more oxygen vacancies, enabling CeONB to become a promising catalyst for soot oxidation. Thus, CeONB shows a much higher catalytic activity than commercial CeO2 nanoparticle (comCeO) for soot oxidation with a significantly lower ignition temperature (Tig). Moreover, while soot oxidation by comCeO leads to production of CO together with CO2, CeONB can completely convert soot to CO2. The tight contact mode also enables CeONB to exhibit a very low Tig of 310 °C, whereas the existence of NO also enhances the soot oxidation by CeONB to reduce the Tig. The mechanism of NO-assisted soot oxidation is also examined, and validated by DRIFTS to identify the formation and transformation of nitrogen-containing intermediates. CeONB is also recyclable over many consecutive cycles and maintained its high catalytic activity for soot oxidation. These results demonstrate that CeONB is a promising and easily prepared high-aspect-ratio Ce-based catalyst for soot oxidation

Advances in green chemistry and engineering

Abstract Green chemistry and engineering seek for maximizing efficiency and minimizing negative impacts on the environment and human health in chemical production processes. Driven by advances in the principles of environment protection and sustainability, these fields are expected to greatly contribute to achieving sustainable development goals. To this end, many studies have been conducted to develop new approaches within green chemistry and engineering. The Advances in Green Chemistry and Engineering Collection at Scientific Reports aims at gathering the latest research on developing and implementing the principles of green chemistry and engineering

A Study on Performance and Emissions of a 4-Stroke IC Engine Operated on Landfill Gas With Syngas Addition

The aim of this study is to investigate the suitability of landfill gas (LFG) as an alternative fuel for an internal combustion (IC) engine and how to reduce pollutants emissions from LFG operations by adding syngas to LFG. The effect of CO2 fractions in LFG on the engine performance and exhaust emissions such as CO, UHC and NOx are experimentally determined, and a simulated LFG (50% CH4 and 50% CO2) mixed with a simulated syngas consisting of H2 and CO (H2/CO = 2) is also studied. The Honda GC160E engine connected with a small generator which functions as different electrical loads is used for this study. When CO2 fraction in LFG changes from 0% to 50% at 0.8 kW load condition, CO and UHC emissions increase from 241.8ppm to 802.1ppm and from 35.6ppm to 113.4ppm respectively, while NOx emission decreases from 126.7ppm to 99.8ppm. In case of LFG (50% CH4 and 50% CO2)-syngas (H2/CO = 2) mixtures, 5% addition of syngas to LFG at 0.8 kW load condition reduces CO, UHC and NOx emissions from 802.1ppm to 203.1ppm, from 113.4ppm to 11.1ppm and from 99.8ppm to 64.5ppm, respectively. However, when more syngas is added to LFG (10% and 15% syngas in fuel mixture) it does not measurably reduce these emissions any further.</jats:p

Recent achievements in CO₂-assisted and CO₂-catalyzed biomass conversion reactions

Carbon dioxide (CO2) has attracted great interest as a catalyst and reaction medium for the conversion of lignocellulosic biomass into value-added commodity chemicals.</p