Lars J. Pettersson

Hydrogen generation by steam reforming of methanol over copper-based catalysts for fuel cell applications

This paper presents an investigation concerning the reforming of methanol over various base-metal oxide catalysts. Copper-based catalysts were effective for the steam reforming of methanol. The selectivity and conversion was studied in a flow reactor in the temperature interval 180–320°C. The active materials were impregnated on γ-alumina pellets using the wet impregnation method. The promoters used in the investigation were chromium (Cr), zinc (Zn) and zirconia (Zr). The copper content and promoter used played an important role in the catalysts ability to selectively convert methanol at low temperatures. Catalysts with high copper contents generally gave higher conversions and selectivities for the steam reforming reaction. The use of ternary components generally increased the catalyst selectivity towards carbon dioxide. Zirconia had a positive influence on the catalytic performance at low temperatures. The possibilities for the use of reforming systems with copper-based catalysts in fuel cell applications are promising.

State of the art of multi-fuel reformers for fuel cell vehicles : problem identification and research needs

This review is focused on discussions about multi-fuel reformer technology for fuel cell vehicles where techniques for onboard hydrogen generation and gas clean-up processes, as well as fuel considerations and emissions are included. Our conclusion is that the potential for developing a highly efficient, durable and reliable reformer system for automotive applications is considerably higher if dedicated fuel reformers are used instead of applications where all types of fuels ranging from natural gas to heavy diesel fuels can be used. The authors propose that petroleum-derived fuels should be designed for potential use in mobile fuel cell applications. The present literature review together with site visit discussions has led to the conclusion that there are relatively low emissions from fuel cell engines compared to internal combustion engines. However, the major research work on reformers/fuel cells have been performed during steady-state operation. Emissions during start-up, shutdown and transient operation are basically unknown and must be investigated in more detail.

Catalytic combustion of methane over cerium-doped palladium catalysts

Various Pd-supported catalysts have been prepared using three different types of alumina as support material: (a) gamma-alumina, (b) Ba-stabilized alumina, and

Combined methanol reforming for hydrogen generation over monolithic catalysts

An experimental investigation on hydrogen generation from methanol using monolithic catalysts is presented in this paper. The activity and carbon dioxide selectivity for the reforming of methanol over various binary copper-based materials, Cu/Cr, Cu/Zn and Cu/Zr, have been evaluated. The methanol reforming was performed using steam reforming and combined reforming (CMR, a combination of steam reforming and partial oxidation). The CMR process was carried out at two modes of operation: near auto-thermal and at slightly exothermal conditions. The catalysts have been characterized using BET surface area measurement, X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscopy (SEM-EDS). The results show that the choice of catalytic material has a great influence on the methanol conversion and carbon dioxide selectivity of the reforming reaction. The zinc-containing catalyst showed the highest activity for the steam reforming process, whereas the copper/chromium catalyst had the highest activity for the CMR process. The copper/zirconium catalyst had the highest CO2 selectivity for all the investigated process alternatives.

Steam reforming of methanol over copper-based monoliths: the effects of zirconia doping

In this paper, an experimental investigation concerning steam reforming of methanol over various alumina-supported monolithic copper-based catalysts is presented. The activity and carbon dioxide selectivity was studied over two sets of catalysts, one of which was doped with zirconium, with five different copper contents. The zirconium-doped catalyst were less active with respect to the hydrogen yield, however, they were at all times more selective towards carbon dioxide over the entire temperature interval. The catalysts have been characterised using Brunauer-Emmett-Teller (BET) surface area measurement and X-ray diffraction (XRD). The results show that the copper loading and modification of the active material by zirconia doping had a great influence on the methanol conversion and carbon dioxide selectivity of the steam reforming reaction.

Decomposed Methanol as a Fuel—A review

Abstract The use of decomposed methanol, i.e., hydrogen and carbon monoxide, in spark-ignition engines is reviewed. The emphasis is on onboard decomposition and the paper docs not deal with engines fueled by stored hydrogen. The paper concentrates mostly on the experimental work performed using catalytically decomposed methanol, where the methanol is used as a hydrogen carrier. The greatest potential for this type of engine, besides the low energy consumption, lies in the low emissions of nitrogen oxides when running at lean air/fuel ratios. An active and selective catalyst for the decomposition reaction is essential for the utilization of this concept. A literature review on catalyst investigations is included. Neat methanol engines arc not readily started at low ambient temperatures. The possibility of using decomposed methanol as a cold start fuel for methanol engines is reviewed. Decomposed methanol has been proposed as a fuel for gas turbines. A brief review of this subject is also included.

A Brief History of Catalysis

Historical studies are usually divided into segments of time that were marked by intellectual progress or specific achievements. Some periods are clearly identified by great events or an individual accomplishment that revolutionizes the entire concept. However, in most cases the advancement from one period to another is not marked by distinct accomplishments, but rather the result of a series of advances. This paper follows this conventional style and we have divided our subject of catalysis into five distinct periods.

Preparation of alumina-supported palladium catalysts for complete oxidation of methane

Alumina-supported palladium catalysts (Pd/Al2O3) have been prepared by incipient wetness (IW), grafting (G) and microemulsion techniques (ME). Two slightly different microemulsion methods have been ...

Deactivation of copper-based catalysts for fuel cell applications

The activity of copper catalysts for the steam reforming of methanol was investigated under deactivating conditions. The effects of adding poisonous substances which can occur in the fuel, such as sulphur and chlorine, were studied. Thermal ageing by sintering was observed while exposing the catalyst to high temperatures. The catalyst activity for steam reforming was greatly affected by the addition of low concentrations of sulphur and chlorine. Sulphur was more detrimental to the catalyst than chlorine.

Onboard hydrogen generation by methanol decomposition for the cold start of neat methanol engines

Abstract Hydrogen is excellent for use as a cold starting aid for methanol vehicles at low ambient temperatures. Hydrogen can be produced by partial decomposition of methanol at the moment of start. This enables the spark-ignition engine to utilize only one fuel and there is no need for fuel additives or a separate starting fuel. An experimental investigation indicates that it is possible to start a neat methanol engine down to at least −30°C using the product gas from the cold start reactor described in this paper. The engine ignited on the mixture, but additional methanol was needed to establish proper idling. The drivability was good directly after cold start by the addition of the hydrogen-rich gas. At room temperature it was possible to both start the engine and reach an acceptable engine speed at idling, with the use of only the gas from the cold start reactor.