A modified twin-screw extruder incorporated with a filtration device was used as a liquid/solid separator for xylose removal from steam exploded corncobs. A face centered central composite design was used to study the combined effects of various enzymatic hydrolysis process variables (enzyme loading, surfactant addition, and hydrolysis time) with two differently extruded corncobs (7% xylose removal, 80% xylose removal) on glucose conversion. The results showed that the extrusion process led to an increase in cellulose crystallinity, while structural changes could also be observed via SEM. A quadratic polynomial model was developed for predicting the glucose conversion and the fitted model provided an adequate approximation of the true response as verified by the analysis of variance (ANOVA).

Front-end design decisions for a process to produce sustainable aviation turbine fuel from waste materials were presented. The design employs distributed conversion of wastes to oils, which are then transported to a central facility for gasification, syngas cleaning, Fischer-Tropsch synthesis and refining, that is, a spoke-and-hub approach. Different aspects of the front-end design, that is, the steps up to syngas cleaning, were evaluated. The evaluation employed a combination of case studies, calculations, experimental investigations, and literature review. The supply of sustainable aviation fuel (SAF) as a 50:50 mixture of wastederived and petroleum-derived kerosene to meet the demand of an international airport (Pearson, Toronto) was employed as case study. The amount of raw material required made it impractical to make use of only one type of waste. Using the same set of assumptions, it was shown that in terms of cumulative transport distance required, a spoke-and-hub approach was twice as efficient as centralized processing only. Technologies for decentralized production of oils were assessed, and oils produced by pyrolysis and hydrothermal liquefaction (HTL) in pilot-scale and larger facilities were procured and characterized. These oils were within the broader compositional space of pyrolysis oils and HTL oils reported in laboratory studies. The oil compositions were employed to study the impact of oil composition on entrained flow gasification. Thermodynamic equilibrium calculations of pyrolysis and HTL oil entrained flow gasification resulted in H 2 / CO ratios of syngas and O 2 consumption rates in a narrow range, despite the diversity of feeds. At the same time, to produce an equal molar amount of syngas (H 2 + CO), less HTL oil than pyrolysis oil was required as feed. Gas cleaning technologies were reviewed to ascertain types of contaminants anticipated after gasification, their removal effectiveness, and Fischer-Tropsch catalyst poisoning 1763

Ni-Co bimetallic and Ni or Co monometallic catalysts prepared for CO 2 reforming of methane were tested with the stimulated biogas containing steam, CO 2 , CH 4 , H 2 , and CO. A mix of the prepared CO 2 reforming catalyst and a commercial steam reforming catalyst was used in hopes of maximizing the CO 2 conversion. Both CO 2 reforming and steam reforming of CH 4 occurred over the prepared Ni-Co bimetallic and Ni or Co monometallic catalysts when the feed contained steam. However, CO 2 reforming did not occur on the commercial steam reforming catalyst. There was a critical steam content limit above which the catalyst facilitated no more CO 2 conversion but net CO 2 production for steam reforming and water-gas shift became the dominant reactions in the system. The Ni-Co bimetallic catalyst can convert more than 70% of CO 2 in a biogas feed that contains~33 mol% of CH 4 , 21.5 mol% of CO 2 , 12 mol% of H 2 O, 3.5 mol% of H 2 , and 30 mol% of N 2. The H 2 /CO ratio of the produced syngas was in the range of 1.8-2. X-ray absorption spectroscopy of the spent catalysts revealed that the metallic sites of Ni-Co bimetallic, Ni and Co monometallic catalysts after the steam reforming of methane reaction with equimolar feed (CH 4 :H 2 O:N 2 = 1:1:1) experienced severe oxidation, which led to the catalytic deactivation.

A model for industrial top‐fired dry reforming of methane (DRM) and for combined dry reforming and steam reforming of methane was developed for the first time. The model calculates and gives predictions on the temperature profiles for fuel gas, tube walls, and process gas, as well as the process gas composition profiles over the length of the tubes. Radiative heat transfer is modeled by Hottel Zone method. Material and energy balances are solved numerically using Newton‐Raphson solver. Kinetic models for two different DRM catalysts are applied in the model for comparison. Simulation results show that water–gas shift reaction is important in DRM and addition of steam in the feed of process gas is beneficial for industrial production. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2060–2071, 2017

Fully formulated synthetic jet fuel is an aviation turbine fuel that does not contain petroleum‐derived kerosene and comprises the hydrocarbon compound classes n‐alkanes, isoalkanes, cycloalkanes, and aromatics. When the aim is to produce sustainable aviation fuel, one potential process pathway is by indirect liquefaction via Fischer–Tropsch synthesis. Fischer–Tropsch synthesised paraffinic kerosene plus aromatics (FT SPK/A) is a product that is fully formulated and can in principle be qualified as Jet A‐1. The synthetic jet fuel must ultimately meet all of the Jet A‐1 specifications. However, there are still hurdles on the path toward global approval of fully formulated synthetic jet fuel. In this study, several different refining pathways are shown that can be employed to produce FT SPK/A. The refining pathways have the desirable attribute of being generally useful and not limited to a specific refining technology. A case study is also presented in which FT SPK/A was produced, characterised and compared to Jet A‐1 specification requirements. It illustrated that it was practical to produce a fully formulated jet fuel via Fischer–Tropsch refining.