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Subject: search.filters.subject.Dimethyl ether

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    Effects of Zinc and Aluminum on the CuO Crystalline Size for Direct Dimethyl Ether Synthesis from Syngas
    (2021-09-01)
    Thongkam, Montree
    ;
    Piyabunditgul, Nanchapak
    ;
    Trisupakitti, Somsuk
    ;
    Rungrojchaipon, Pesak
    The effects of zinc and aluminum on the CuO crystalline size for direct dimethyl ether (DME) synthesis from syngas were investigated. Metal oxide catalysts were synthesized with various molar ratios of CuO by the precipitation method, and by the co-precipitation method with CuO/ZnO (CZ), CuO/ZnO/Al<inf>2</inf>O<inf>3</inf> (CZA), and CZA at ratios of 1:1, 2:2:1, and 6:3:1, respectively. The acid catalysts (γ-Al<inf>2</inf>O<inf>3</inf>, HZSM-5) were added to the metal oxide catalysts by physical mixing. The catalysts were characterized morphologically and their acidities were determined. Loading of zinc and aluminum at different ratios showed that CZA (2:2:1) gave the smallest CuO crystalline size, appropriate for the methanol synthesis reaction. γ-Al<inf>2</inf>O<inf>3</inf> has a weak to moderate acidity range, suitable for DME synthesis. Moreover, the bifunctional catalyst, CZA (2:2:1)/γ-Al<inf>2</inf>O<inf>3</inf>, had the highest surface area as well as the highest %CO conversion and %DME selectivity.
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    Comparative exergoeconomic analysis of indirect and direct bio-dimethyl ether syntheses based on air-steam biomass gasification with CO2 utilization
    (2020-10-15)
    Nakyai, Teeranun
    ;
    Patcharavorachot, Yaneeporn
    ;
    Arpornwichanop, Amornchai
    ;
    Saebea, Dang
    Dimethyl ether (DME) is a potential energy source because it is a clean fuel and a crucial intermediate in various chemical productions. The main purposes of this work were to assess and compare the indirect and direct bio-DME syntheses from air-steam biomass gasification with CO<inf>2</inf> utilization using energetic, exergetic, and exergoeconomic analyses. The effects of hydrogen to carbon monoxide (H<inf>2</inf>/CO) and carbon dioxide to carbon monoxide (CO<inf>2</inf>/CO) ratios on DME yield of the indirect and direct processes were firstly investigated. When considering the combined processes, the results were found that the DME yield of the system with direct DME synthesis is higher than that of the indirect system. Moreover, the energy consumption and exergy destruction of biomass gasification and DME synthesis processes in the indirect system are considerably higher when compared to the direct system. For exergoeconomic analysis, the DME unit cost of the direct system (1.66 $/kg DME) also has lower than that of the system with indirect DME synthesis (2.26 $/kg DME). In addition, the CO<inf>2</inf> emission of both systems was also considered. The CO<inf>2</inf> emission intensity of the system with direct DME synthesis shows 32.35% lower than the system with indirect DME synthesis.
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    Process development of sustainable biorefinery system integrated into the existing pulping process
    (2020-05-10)
    Mongkhonsiri, Ghochapon
    ;
    Charoensuppanimit, Pongtorn
    ;
    Anantpinijwatna, Amata
    ;
    Gani, Rafiqul
    ;
    Assabumrungrat, Suttichai
    The change of paper consumption trend may jeopardize the future of pulp and paper industry. This work aims to design and develop the integrated network of biochemical and biofuel productions into existing pulp mills for sustainable purposes. The systematic methodology aided by computation tools is undertaken using the three-stage approach including process synthesis, design and innovation. Previously, the optimal technologies of the biorefinery-integrated pulping processes were successfully determined in the synthesis stage providing the highest cost-effective incorporation; 48 million USD/year of profit was estimated according to the integration of succinic acid and dimethyl ether productions into the soda pulping process. Herein, the process designs of the integrated processes were performed followed by evaluations of the process performances and identifications of the hot spots and targets for establishments of the innovations. In this work, the biomass gasification option is designed and implemented to enhance the material and energy utilizations in the previously determined biorefinery-integrated pulping processes. Electricity and biofuel are produced and sold, which contributes positively to the economic and environmental impacts of these processes. The hot spots and targets are subsequently identified prior to the innovation stage. According to this stage, the cleaner alternatives that implements the CO<inf>2</inf> utilization via methanol synthesis and solar cell installations are selected in order to minimize the CO<inf>2</inf> emission. A net CO<inf>2</inf> reduction of 42% is achieved when the cleaner alternatives are applied. Accordingly, these biorefinery-integrated innovations are not only conducive to the enhanced sustainability of existing pulp mills but also adaptive in response to the change of paper consumption trend.