Using apparent activation energy as a reactivity criterion for biomass pyrolysis

The reactivity of chemically isolated lignocellulosic blocks, namely, α-cellulose, holocellulose, and lignin, has been rationalized on the basis of the dependence of the effective activation energy (Eα) upon conversion (α) determined via the popular isoconversional kinetic analysis, Friedman’s method. First of all, a detailed procedure for the thermogravimetric data preparation, kinetic calculation, and uncertainty estimation was implemented. Resulting Eα dependencies obtained for the slow pyrolysis of the extractive-free Eucalyptus grandis isolated α-cellulose and holocellulose remained constant for 0.05 < α < 0.80 and equal to 173 ± 10, 208 ± 11, and 197 ± 118 kJ/mol, thus confirming the single-step nature of pyrolysis. On the other hand, large and significant variations in Eα with α from 174 ± 10 to 322 ± 11 kJ/mol in the region of 0.05 and 0.79 were obtained for the Klason lignin and reported for the first time. The non-monotonic nature of weight loss at low and high conversions had a direct consequence on the confidence levels of Eα. The new experimental and calculation guidelines applied led to more accurate estimates of Eα values than those reported earlier. The increasing Eα dependency trend confirms that lignin is converted into a thermally more stable carbonaceous material

RoboGlove - A Robonaut Derived Multipurpose Assistive Device

The RoboGlove is an assistive device that can augment human strength, endurance or provide directed motion for use in rehabilitation. RoboGlove is a spinoff of the highly successful Robonaut 2 (R2) system developed as part of a partnership between General Motors and NASA. This extremely lightweight device employs an actuator system based on the R2 finger drive system to transfer part or the entire grasp load from human tendons to artificial ones contained in the glove. Steady state loads ranging from 15 to 20 lbs. and peaks approaching 50 lbs. are achievable. The technology holds great promise for use with space suit gloves to reduce fatigue during space walks. Tactile sensing, miniaturized electronics, and on-board processing provide sufficient flexibility for applications in many industries. The following describes the design, mechanical/electrical integration, and control features of the glove

RoboGlove-A Grasp Assist Device for Earth and Space

The RoboGlove is an assistive device that can augment human strength, endurance or provide directed motion for use in rehabilitation. RoboGlove is a spinoff of the highly successful Robonaut 2 (R2) system developed as part of a partnership between General Motors and NASA. This extremely lightweight device employs an actuator system based on the R2 finger drive system to transfer part or the entire grasp load from human tendons to artificial ones contained in the glove. Steady state loads ranging from 15 to 20 lbs. and peaks approaching 50 lbs. are achievable. Work is underway to integrate the RoboGlove system with a space suit glove to add strength or reduce fatigue during spacewalks. Tactile sensing, miniaturized electronics, and on-board processing provide sufficient flexibility for applications in many industries. The following describes the design, mechanical/electrical integration, and control features of the glove in an assembly-line configuration and discusses work toward the space suit application

Using biomass-based fuels including pyrolysis liquids for power and CHP production

The use of biomass-derived liquids (in short: bioliquids) instead of solid biomass can help overcome some of the barriers hindering a wider use of biomass in smaller-scale CHP systems. Relevant bioliquids included biodiesel, vegetable oils as well straight and upgraded pyrolysis oil. In this joint EU-Russian research project Bioliquids-CHP prime movers (engines and turbines) will be developed and modified so that these can run efficiently on bioliquids. At the same time, bioliquids will be upgraded and blended in order to facilitate their use in prime movers. Preliminary results with regard to bioliquid selection, production, and characterisation; the selection and modification of a micro gas turbine; and the development of engines and components are discussed. The research also covers NOx emission reduction and control and an assessment of the benefits and economics of bioliquids-based CHP systems in EU and Russian markets

Robonaut 2 - The First Humanoid Robot in Space

NASA and General Motors have developed the second generation Robonaut, Robonaut 2 or R2, and it is scheduled to arrive on the International Space Station in late 2010 and undergo initial testing in early 2011. This state of the art, dexterous, anthropomorphic robotic torso has significant technical improvements over its predecessor making it a far more valuable tool for astronauts. Upgrades include: increased force sensing, greater range of motion, higher bandwidth and improved dexterity. R2 s integrated mechatronics design results in a more compact and robust distributed control system with a faction of the wiring of the original Robonaut. Modularity is prevalent throughout the hardware and software along with innovative and layered approaches for sensing and control. The most important aspects of the Robonaut philosophy are clearly present in this latest model s ability to allow comfortable human interaction and in its design to perform significant work using the same hardware and interfaces used by people. The following describes the mechanisms, integrated electronics, control strategies and user interface that make R2 a promising addition to the Space Station and other environments where humanoid robots can assist people

Insights into the ceria-catalyzed ketonization reaction for biofuels applications

The ketonization of small organic acids is a valuable reaction for biorenewable applications. Ceria has long been used as a catalyst for this reaction; however, under both liquid and vapor phase conditions, it was found that given the right temperature regime of about 150-300 °C, cerium oxide, which was previously believed to be a stable catalyst for ketonization, can undergo bulk transformations. This result, along with other literature reports, suggest that the long held belief of two separate reaction pathways for either bulk or surface ketonization reactions are not required to explain the interaction of cerium oxide with organic acids. X-ray photon spectroscopy, scanning electron microscopy, and temperature programmed decomposition results supported the formation of metal acetates and explained the occurrence of cerium reduction as well as the formation of cerium oxide/acetate whiskers. After thermogravimetry/mass spectrometry and FT-IR experiments, a single reaction sequence is proposed that can be applied to either surface or bulk reactions with ceria

Reaction Chemistry and Kinetics of Corn Stalk Pyrolysis without and with Ga/HZSM-5

The bifunctional Ga/HZSM-5 catalyst has been proven having the capability to increase the selectivity of aromatics production during catalytic pyrolysis of furan and woody biomass. However, the reaction chemistry and kinetics of pyrolysis of herbaceous biomass promoted by Ga/HZSM-5 is rarely reported. Pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) analysis and non-isothermal thermogravimetric analysis at four heating rates were carried out to investigate the decomposition behavior and pyrolysis kinetics of corn stalk without and with Ga/HZSM-5. The effective activation energies for corn stalk pyrolysis were calculated by using the Friedman isoconversional method. The Py–GC/MS analysis results indicated that the Ga/HZSM-5 catalyst had a high selectivity toward producing the aromatic chemicals of xylene, toluene and benzene, whereas the major products from non-catalytic pyrolysis of corn stalk were oxygenated compounds. The presence of Ga/HZSM-5 could significantly reduce the effective activation energies of corn stalk pyrolysis from 159.9–352.4 kJ mol−1 to 41.6–99.8 kJ mol−1 in the conversion range of 0.10–0.85

In-situ upgrading of Napier grass pyrolysis vapour over microporous and hierarchical mesoporous zeolites

This study presents in-situ upgrading of pyrolysis vapour derived from Napier grass over microporous and mesoporous ZSM-5 catalysts. It evaluates effect of process variables such catalyst–biomass ratio and catalyst type in a vertical fixed bed pyrolysis system at 600 °C, 50 °C/min under 5 L/min nitrogen flow. Increasing catalyst–biomass ratio during the catalytic process with microporous structure reduced production of organic phase bio-oil by approximately 7.0 wt%. Using mesoporous catalyst promoted nearly 4.0 wt% higher organic yield relative to microporous catalyst, which translate to only about 3.0 wt% reduction in organic phase compared to the yield of organic phase from non-catalytic process. GC–MS analysis of bio-oil organic phase revealed maximum degree of deoxygenation of about 36.9% with microporous catalyst compared to the mesoporous catalysts, which had between 39 and 43%. Mesoporous catalysts promoted production olefins and alkanes, normal phenol, monoaromatic hydrocarbons while microporous catalyst favoured the production of alkenes and polyaromatic hydrocarbons. There was no significant increase in the production of normal phenols over microporous catalyst due to its inability to transform the methoxyphenols and methoxy aromatics. This study demonstrated that upgrading of Napier grass pyrolysis vapour over mesoporous ZSM-5 produced bio-oil with improved physicochemical properties