Hydrogen production reactions from carbon feedstocks: fossil fuels and biomass.

The recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to formate/formic acid, methanol, and dimethyl ether are thoroughly reviewed, with special emphasis on thermodynamics and catalyst design considerations. After introducing the main motivation for the development of such processes, we first summarize the most important aspects of CO2 capture and green routes to produce H2. Once the scene in terms of feedstocks is introduced, we carefully summarize the state of the art in the development of heterogeneous catalysts for these important hydrogenation reactions. Finally, in an attempt to give an order of magnitude regarding CO2 valorization, we critically assess economical aspects of the production of methanol and DME and outline future research and development directions.

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Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Catalyzed CO2 Hydrogenation Processes.

The present rate of economic growth is unsustainable without saving of fossil energy like crude oil, natural gas or coal. Thus mankind has to rely on the alternate/renewable energy sources like biomass, hydropower, geothermal energy, wind energy, solar energy, nuclear energy, etc. On the other hand, suitable waste management strategy is another important aspect of sustainable development. The growth of welfare levels in modern society during the past decades has brought about a huge increase in the production of all kinds of commodities, which indirectly generate waste. Plastics have been one of the materials with the fastest growth because of their wide range of applications due to versatility and relatively low cost. Since the duration of life of plastic products is relatively small, there is a vast plastics waste stream that reaches each year to the final recipients creating a serious environmental problem. Again, because disposal of post consumer plastics is increasingly being constrained by legislation and escalating costs, there is considerable demand for alternatives to disposal or land filling. Advanced research in the field of green chemistry could yield biodegradable/green polymers but is too limited at this point of time to substitute the non-biodegradable plastics in different applications. Once standards are developed for degradable plastics they can be used to evaluate the specific formulations of materials which will find best application in this state as regards their performance and use characteristics. Among the alternatives available are source reduction, reuse, recycling, and recovery of the inherent energy value through waste-to-energy incineration and processed fuel applications. Production of liquid fuel would be a better alternative as the calorific value of the plastics is comparable to that of fuels, around 40 MJ/kg. Each of these options potentially reduces waste and conserves natural resources. Plastics recycling, continues to progress with a wide range of old and new technologies. Many research projects have been undertaken on chemical recycling of waste plastics to fuel and monomer. This is also reflected by a number of pilot, demonstration, and commercial plants processing various types of plastic wastes in Germany, Japan, USA, India, and elsewhere. Further investigations are required to enhance the generation of value added products (fuel) with low investments without affecting the environment. The paper reviews the available literature in this field of active research and identifies the gaps that need further attention.

Thermolysis of waste plastics to liquid fuel: A suitable method for plastic waste management and manufacture of value added products—A world prospective

Sulfur-passivated nickel catalysts for carbon-free steam reforming of methane

On the interpretation of the NH3-TPD patterns of H-ZSM-5 and H-mordenite

Infrared and temperature-programmed desorption study of the acidic properties of ZSM-5-type zeolites

Sulfur poisoning of boudouard and methanation reactions on nickel catalysts

A B S T R A C T A process is disclosed for the preparation of a gas mixture having a high content of methane by the catalytic conversion at a pressure of 1-150 bar and a temperature of 250-853°C of a synthesis gas (feed gas) containing hydrogen and carbon oxides and optionally other gases, wherein the feed gas contains at least 10 ppm (calculated as H2S) of one or more sulphur compounds and the conversion takes place in the presence of a catalyst containing vanadium and/or molybdenum in the form of free metal, salt, oxide, or sulphide, on a porous, oxidic, support consisting of or containing at least 30% by weight of one or more oxides of one or more metals belonging to group IV on the Periodic Table of Elements. It has been found that thereby it is possible to obtain a product gas having a high proportion of methane and a special advantage is that a high pro-portion of the higher hydrocarbons resulting in the product gas is C2-hydrocarbons.

Process and catalyst for the preparation of a gas mixture having a high content of methane

A gas mixture rich in ethan and/or ethylene is prepared by the conversion of a synthesis gas mixture containing hydrogen, carbon oxides and, optionally, other gases in the presence of one or more gaseous sulphur compounds, in an amount of at least 10 ppm by volume, preferably at least 200 ppm, calculated as H 2 S, utilizing a catalyst consisting of one or more metals of group V-B and/or VI-B of the Periodic Table of Elements, preferably molybdenum and/or vanadium, together with one or more iron group metals each metal being in the form of free metal, oxide, or sulphide, the catalyst being supported on a porous, refractory oxidic support containing titanium dioxide. There is achieved a high activity and notably a high selectivity for the formation of ethane/ethylene, small amounts of propane, not insignificant amounts of methane and almost full suppression of the formation of higher hydrocarbons. The invention also relates to the catalyst prepared by impregnation or coprecipitation techniques.

Karsten Pedersen

Papers

Infrared and temperature-programmed desorption study of the acidic properties of ZSM-5-type zeolites

Sulfur poisoning of boudouard and methanation reactions on nickel catalysts

Process and catalyst for the preparation of a gas mixture having a high content of methane

Process and catalyst for the preparation of a gas mixture having a high content of C2 -hydrocarbons

Method and catalyst for manufacturing gas mixture containing high quantity of c22hydrocarbons