Scope of biodiesel from oils of woody plants: a reviewThangaraj, Baskar; Solomon, Pravin Raj
2020 Clean Energy
doi: 10.1093/ce/zkaa006
Non-edible oils obtained from chosen non-conventional woody plants are considered as potential raw materials for biodiesel production. These plants mostly grow in wastelands. Structural characteristics of these oils as raw material are very much in tune with the properties of biodiesel such as long-chain hydrocarbon, having an adequate level of unsaturation with branched chain. Four primary methods are being followed to make biodiesel from vegetable oil. They are direct use through blending, microemulsion, thermal cracking (pyrolysis) and transesterification. Non-edible oil would eliminate the issue of food vs fuel. The biodiesel manufactured from oils of woody plants may partially reduce the demand for liquid-fuel energy and addresses the environmental consequences of using fossil fuels. Oil from a total of 17 species of woody plants (Angiosperms) belonging to 14 families are considered in this paper. The habit, habitat and geographical distribution of each species are also presented. The physico-chemical properties of their oil, with special reference to the fatty-acid profile that ultimately decides the characteristics of the biodiesel prepared from them, are reviewed.
Post-combustion slipstream CO2-capture test facility at Jiangyou Power Plant, Sichuan, China: facility design and validation using 30% wt monoethanolamine (MEA) testingWang, Baodeng; Cui, Qian; Zhang, Guoping; Long, Yinhua; Sun, Yongwei; Zhao, Xinglei; He, Zhendong; Ku, Anthony Y
2020 Clean Energy
doi: 10.1093/ce/zkaa002
Given the dominant share of coal in China’s energy-generation mix and the fact that >50% of the power plants in the country are currently <15 years old, efforts to significantly reduce China’s CO2 footprint will require the deployment of CO2 capture across at least part of its fleet of coal-fired power plants. CO2-capture technology is reaching commercial maturity, but it is still necessary to adapt the technology to regional conditions, such as power-plant design and flexible operation in the China context. Slipstream facilities provide valuable field data to support the commercialization of CO2 capture. We have built a slipstream facility at Jiangyou power plant in Sichuan that will allow us to explore China-relevant issues, especially flexible operation, over the next few years. We plan to share our results with the broader CO2-capture and CO2-storage (CCS) community to accelerate the deployment of CCS in China. This paper describes the design of the slipstream facility and presents results from our steady-state qualification tests using a well-studied benchmark solvent: 30% wt monoethanolamine (MEA). The results from our MEA tests compare favorably to results reported from other slipstream-test facilities around the world, allowing us to commission our system and establish a reference baseline for future studies.
Investigation of adsorption/desorption performance by aminopropyltriethoxysilane grafted onto different mesoporous silica for post-combustion CO2 captureMuchan, Pailin; Saiwan, Chintana; Nithitanakul, Manit
2020 Clean Energy
doi: 10.1093/ce/zkaa003
Mesoporous silicas with hexagonal structure (MCM-41 and SBA-15) and cubical interconnected pore structure (KIT-6) were synthesized and modified with aminopropyltriethoxysilane (APTES) for using as adsorbents in carbon-dioxide (CO2)-adsorption application. The CO2-adsorption experiment was carried out at room temperature and atmospheric pressure using 15% CO2 with a flow rate of 20 mL/min and the desorption experiment was carried out at 100°C under N2 balance with a flow rate of 20 mL/min. The adsorption capacity and adsorption rate of all modified mesoporous silicas were enhanced due to the presence of primary amine in the structure, which was able to form a fast chemical reaction with CO2. All adsorbents showed good adsorption performance stability after using over five adsorption/desorption cycles. Due to the effect of the adsorbents’ porous structure on the adsorption/desorption process, an adsorbent with sufficient pore-size diameter and pore volume together with interconnected pore, KIT-6, represents a promising adsorbent that gave the optimum adsorption/desorption performance among others. It showed reasonable adsorption capacity with a high rate of adsorption. In addition, it could also be regenerated with 99.72% efficiency using 12.07 kJ/mmolCO2 of heat duty for regeneration.
Effect of additives on mercury partitioning in wet-limestone flue-gas desulfurizationMasoomi, Ida; Heidel, Barna; Schmid, Marc Oliver; Scheffknecht, Günter
2020 Clean Energy
doi: 10.1093/ce/zkaa005
The wet-flue-gas desulfurization (FGD) process plays an important role in removing water-soluble flue-gas components such as sulphur dioxide (SO2) and oxidized mercury compounds. Under the reducing environment of the FGD, there is the possibility of re-emission of the already absorbed mercury (Hg) to the gas phase, which may be diminished by the utilization of specific additives. In this study, the effect of two different additives on Hg re-emission from the aqueous phase and Hg partitioning in gypsum and filtrate of a lab-scale wet-limestone FGD is investigated. Furthermore, the behaviour of additives in the presence of different halides is studied. The studied additives are TMT 15® as a sulphidic precipitating agent, which forms non-soluble mercury compounds, and activated lignite (AL) as a carbon-based sorbent, which adsorbs Hg compounds from the aqueous phase. TMT 15® has no significant effect on SO2 absorption; on the other hand, addition of AL improves the SO2-removal efficiency by up to 30%. Using both additives, Hg re-emission is suppressed in all the experimented cases except for AL in the absence of halides, in which Hg re-emission shows no change. Thus, the need to form nucleophilic oxidized mercury compounds in the slurry for the adsorption of oxidized mercury on AL can be concluded. Usage of both additives improves Hg retention in the slurry to different extents. It is shown that, for the additive-free slurries, the Hg-adsorption capacity of the solid fraction of the slurry is the limiting parameter. Moreover, the utilization of both additives results in a significant increase in the Hg concentration of solid fraction. The correlation between redox potential and partitioning of Hg in the slurry is presented by comparing the change in the redox potential of slurries when additives are used.
3D-printed fuel-cell bipolar plates for evaluating flow-field performancePiri, Hossein; Bi, Xiaotao T; Li, Hui; Wang, Haijiang
2020 Clean Energy
doi: 10.1093/ce/zkaa007
In the last decade, many researchers have focused on developing fuel-cell flow-field designs that homogeneously distribute reactants with an optimum pressure drop. Most of the previous studies are numerical simulations and the few experimental studies conducted have used very simple flow-field geometries due to the limitations of the conventional fabrication techniques. 3D printing is an excellent rapid prototyping method for prototyping bipolar plates (BPPs) to perform experiments on new flow-field designs. The present research investigates the applicability of different 3D-printed BPPs for studying fluid-dynamic behaviour. State-of-the-art flow-field designs are fabricated using PolyJet 3D printing, stereolithographic apparatus (SLA) 3D printing and laser-cutter technologies, and the pressure-drop and velocity profiles are measured for each plate. The results demonstrate that SLA BPPs have great promise in serving as a screening tool in modifying flow-field design with a small feature size.