The potential of glycerol as a value-added commodity

Catalytic valorization of glycerol to hydrogen and syngas

The objective of this review is to analyze potential technologies and their baseline performance of producing hydrogen from catalytic steam reforming of biodiesel byproduct glycerol. High oxygen content and high impurity level of biodiesel byproduct glycerol, as well as the complex intermediates and high coking potential in its thermal degradation, make the modeling, design, and operation of glycerol steam reforming a challenge. Thermal decomposition characterization of biodiesel byproduct glycerol was covered, and the recent developments and methods for high-purity hydrogen production from glycerol steam reforming were illustrated. The thermodynamics constraint of water gas shift reaction can be overcome by the sorption-enhanced steam reforming process, which integrated catalytic steam reforming, water gas shift reaction and in-situ CO2 removal at high temperatures in a single stage reactor. The effectiveness of both the enhanced H2 production and the use of CO2 sorbents have been demonstrated and discussed. The technical challenges to achieve a stable high-purity hydrogen production by the sorption-enhanced steam reforming process included extending operation time, selecting suitable sorbents, finding a way for continuous reaction-regeneration of catalyst and sorbent mixture and improving process efficiencies. The continuous sorption-enhanced steam reforming of glycerol was designed by a simultaneous flow concept of catalyst and sorbent for continuous reaction-regeneration using two slow moving-bed reactors for high-purity hydrogen production and CO2 capture, and in this process, catalyst and sorbent were run in nearly fresh state for H2 production. The sorption-enhanced chemical-looping reforming was also demonstrated. The paper discusses some issues and challenges, along with the possible solutions in order to help in efficient production of hydrogen from catalytic steam reforming of biodiesel byproduct glycerol.

Hydrogen production from catalytic steam reforming of biodiesel byproduct glycerol: Issues and challenges

The steam reforming of the main biodiesel by-product, glycerol, has been catching up the interest of the scientific community in the last years. The use of glycerol for hydrogen production is an advantageous option not only because glycerol is renewable but also because its use would lead to the decrease of the price of biodiesel, thus making it more competitive. Consequently, the use of biodiesel at large scale would significantly reduce CO2 emissions comparatively to fossil fuels. Moreover, hydrogen itself is seen as a very attractive clean fuel for transportation purposes. Therefore, the industrialization of the glycerol steam reforming (GSR) process would have a tremendous global environmental impact. In the last years, intensive research regarding GSR thermodynamics, catalysts, reaction mechanisms and kinetics, and innovative reactor configurations (sorption enhanced reactors (SERs) and membrane reactors (MRs)) has been done, aiming for improving the process effectiveness. In this review, the main challenges and strategies adopted for optimization of GSR process are addressed, namely the GSR thermodynamic aspects, the last developments on catalysis and kinetics, as well as the last advances on GSR performed in SERs and MRs.

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Challenges and strategies for optimization of glycerol steam reforming process

Comparative study of Ni, Co, Cu supported on γ-alumina catalysts for hydrogen production via the glycerol steam reforming reaction

A comparative study on hydrogen production from steam-glycerol reforming: thermodynamics and experimental

A new process has recently been proposed and investigated for low temperature hydrogen production from hydrocarbons with simultaneous CO2 abatement. It is based on a concept involving simultaneous hydrogen production and CO2 removal, which uses a stationary catalyst phase and a continuously moving adsorbent phase for in situ removal of CO2 and ex situ regeneration of adsorbent. This paper summaries the recent developments in the technology using methane (main composition of natual gas) and glycerol (main by-product of biofuels) as the model feedstocks and microsized hydrotalcite as the CO2 adsorbent. The paper consists of an overview of the new technology, associated fundamental studies including dynamics of adsorption, hydrodynamics, solid hold-up and heat transfer, and chemical reactions. Challenges for further development of the technology and process optimisation are also briefly discussed.

Progress in low temperature hydrogen production with simultaneous CO2 abatement

Flow of a gas–solid two-phase mixture through a packed bed is relevant to a number of industrial processes such as heat recovery and filtration of dusty flue gases, iron making in shaft reactors, gas purification, and sorption enhanced reaction processes. In spite of the industrial relevance, little work has been reported in the literature. The limited amount of research work has mainly addressed the macroscopic hydrodynamics in terms of pressure drop and solids hold-ups at the ambient temperature. Very little is done, until fairly recent, on solids motion at the single particle level, hydrodynamics at elevated temperatures and heat transfer. This paper reviews the recent development in the field including both the hydrodynamics and heat transfer of gas–solid two-phase mixtures flowing through packed beds, which is believed to represent the state-of-the-art in the field. The review is not aimed to be exhaustive but rather focused on our own work carried out over the past few years in the Institute of Particle Science & Engineering at the University of Leeds. And some of our results are compared with that of other groups.

http://pub.nsfc.gov.cn/pinsen/ch/reader/create_pdf.aspx?file_no=20081185&flag=1&journal_id=pinsen

Ngoc T. Cong

Papers

A comparative study on hydrogen production from steam-glycerol reforming: thermodynamics and experimental

Progress in low temperature hydrogen production with simultaneous CO2 abatement

Hydrodynamics and heat transfer of gas–solid two-phase mixtures flowing through packed beds – a review

Progress in Low Temperature Hydrogen Production with Simultaneous CO2 Abatement