Amber Broch

Bio: Amber Broch is an academic researcher from Desert Research Institute. The author has contributed to research in topics: Hydrothermal carbonization & Raw material. The author has an hindex of 14, co-authored 21 publications receiving 2590 citations. Previous affiliations of Amber Broch include Nevada System of Higher Education.

Review of biodiesel composition, properties, and specifications

Abstract: Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils. Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties – including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics – are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.

Hydrothermal Carbonization (HTC) of Lignocellulosic Biomass

Abstract: Hydrothermal carbonization (HTC) of biomass involves contacting raw feedstock with hot, pressurized water. Through a variety of hydrolysis, dehydration, and decarboxylation processes, gaseous and water-soluble products are produced, in addition to water itself and a solid char. In this experimental effort, a 2 L Parr stirred pressure vessel was used to apply the HTC process to a mixed wood feedstock. The effects of the reaction conditions on product compositions and yields were examined by varying temperature over the range of 215−295 °C and varying reaction hold time over the range of 5−60 min. With increasing temperature and time, the amounts of gaseous products and produced water increased, while the amount of HTC char decreased. The energy density of the char increased with reaction severity. At reaction conditions of 255 °C for 30 min, the HTC char had 39% higher energy density than the raw biomass feedstock. Aqueous solutions from HTC experiments at lower temperatures (215−235 °C) contained signific...

Hydrothermal carbonization (HTC) of selected woody and herbaceous biomass feedstocks

Abstract: A hydrothermal carbonization (HTC) process was applied to six biomass feedstocks—three woody and three herbaceous. Each feedstock was treated in liquid water for 30 min at temperatures ranging from 175 to 295 °C. Gaseous, aqueous, and solid hydrochar products were characterized to examine the effects of process temperature upon product yields, compositions, and energy densification. Thorough mass balance determinations were made for all HTC experiments. With increasing temperature, the mass of solid hydrochar products was reduced, but energy density increased. At temperatures ≥255 °C, hydrochars produced from woody feedstocks had energy contents of 28–30 MJ/kg, comparable to subbituminous coal. Hydrochars produced from herbaceous feedstocks had somewhat lower energy contents. With increasing temperature, the atomic O/C ratio of all samples was reduced from 0.6 to 0.7 in the raw feedstocks to approximately 0.2 in the hydrochars. Gaseous products increased with increasing HTC temperature, reaching 10–12 % at ≥275 °C. The sum of sugar and organic acid yields was typically 8–12 %, although the composition of these aqueous products varied with temperature. Water was produced in yields of 10–20 % at process temperatures of ≥255 °C.

Effect of hydrothermal carbonization reaction parameters on the properties of hydrochar and pellets

Abstract: Hydrothermal carbonization (HTC) is a promising upgrading process to convert various low energy-density lignocellulosic biomass materials to homogeneous, energy-dense HTC biochar, known as hydrochar. A novel two-chamber reactor was designed and built to investigate the effects of HTC reaction parameters on the resulting hydrochar produced from woody biomass. Reaction parameters investigated included temperature (200–230°C), feedstock particle size (0.60–2.38 mm), and reaction time (1–5 min). Mass yield and higher heating value (HHV) of the hydrochar products were determined as two important measures. Reaction temperature was found to have a much stronger influence on mass yield and HHV than particle size or reaction time. Hydrochar can be formed readily into robust, dense pellets, without requiring any additional binding agent. Pellet density ranged from 1260 to 1320 kg m−3, while volumetric energy density ranged from 27.3 to 29.5 GJ m−3. Several analyses were performed on hydrochar pellets, including ultimate analysis, proximate analysis, and water immersion tests. Results are presented and discussed to illustrate the chemical composition, energy density, and water resistance of hydrochar pellets. This study confirmed that the HTC process can transform lignocellulosic biomass into a solid fuel with favorable properties, and provides insightful guidance regarding optimum reaction parameters for producing hydrochar and pellets in a continuous, industrial process. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 676–680, 2014

Review of biodiesel composition, properties, and specifications

Abstract: Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils. Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties – including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics – are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.

A comparative review of biochar and hydrochar in terms of production, physico-chemical properties and applications

Abstract: Slow-pyrolysis of biomass for the production of biochar, a stable carbon-rich solid by-product, has gained considerable interest due to its proven role and application in the multidisciplinary areas of science and engineering. An alternative to slow-pyrolysis is a relatively new process called hydrothermal carbonization (HTC) of biomass, where the biomass is treated with hot compressed water instead of drying, has shown promising results. The HTC process offers several advantages over conventional dry-thermal pre-treatments like slow-pyrolysis in terms of improvements in the process performances and economic efficiency, especially its ability to process wet feedstock without pre-drying requirement. Char produced from both the processes exhibits significantly different physiochemical properties that affect their potential applications, which includes but is not limited to carbon sequestration, soil amelioration, bioenergy production, and wastewater pollution remediation. This paper provides an updated review on the fundamentals and reaction mechanisms of the slow-pyrolysis and HTC processes, identifies research gaps, and summarizes the physicochemical characteristics of chars for different applications in the industry. The literature reviewed in this study suggests that hydrochar (HTC char) is a valuable resource and is superior to biochar in certain ways. For example, it contains a reduced alkali and alkaline earth and heavy metal content, and an increased higher heating value compared to the biochar produced at the same operating process temperature. However, its effective utilization would require further experimental research and investigations in terms of feeding of biomass against pressure; effects and relationships among feedstocks compositions, hydrochar characteristics and process conditions; advancement in the production technique(s) for improvement in the physicochemical behavior of hydrochar; and development of a diverse range of processing options to produce hydrochar with characteristics required for various industry applications.

Net-zero emissions energy systems

Abstract: Some energy services and industrial processes-such as long-distance freight transport, air travel, highly reliable electricity, and steel and cement manufacturing-are particularly difficult to provide without adding carbon dioxide (CO2) to the atmosphere. Rapidly growing demand for these services, combined with long lead times for technology development and long lifetimes of energy infrastructure, make decarbonization of these services both essential and urgent. We examine barriers and opportunities associated with these difficult-to-decarbonize services and processes, including possible technological solutions and research and development priorities. A range of existing technologies could meet future demands for these services and processes without net addition of CO2 to the atmosphere, but their use may depend on a combination of cost reductions via research and innovation, as well as coordinated deployment and integration of operations across currently discrete energy industries.