Marcello De Falco

Hydrogen Production by Ethanol Steam Reforming: Experimental Study of a Pd-Ag Membrane Reactor and Traditional Reactor Behaviour

In this experimental work, the ethanol steam reforming reaction for producing hydrogen was studied in both a traditional reactor (TR) and a Pd-Ag dense membrane reactor (MR). Both reactors have been packed with a commercial Ru-based catalyst. The experimental tests have been performed in the temperature range 400-500 °C and in the pressure range 2.0-3.6 bar.The results are reported in terms of ethanol conversion, hydrogen production, product selectivities and hydrogen recovery (for the MR only). It has been found that the MR is able to increase the ethanol conversion as well as increase the hydrogen production with respect to a traditional reactor. Moreover, part of the hydrogen produced in the MR is recovered as a CO-free hydrogen stream and is suitable for feeding a PEM fuel cell system.

Water Gas Shift Reaction in Pd-Based Membrane Reactors

Water-gas shift reaction is an important industrial reaction, used for producing synthesis gas and ammonia as well as pure hydrogen for supplying at PEM fuel cells. In this work, an overview on water gas shift reaction performed in Pd-based membrane reactors is shown, paying particular attention to the influence on the performances of some operating variables such as reaction temperature, reaction pressure, H2O/CO molar ratio and sweep gas.

Life Cycle Assessment of a High Temperature Molten Salt Concentrated Solar Power Plant

The well-known world energetic matter, mainly due to the worldwide growing energy consumption gone with a reduction of oil and gas availability, and to the environmental effects of the indiscriminate use of fossil fuels in our economy, is leading to the development of clean innovative technologies for the reduction of GHG emissions and the creation of a more sustainable economic structure worldwide. But, realizing and installing renewable energy plants have an environmental “footprint” that has to be evaluated to quantify the real impact of renewable technologies on the environment. Nowadays, the most important tool to evaluate this impact of a product is the Life Cycle Assessment (LCA). To this aim, several impact categories are defined; among these the most important are the Global Warming, the Abiotic Depletion, the Eutrophication, the Acidification, the Land Use and the Human toxicity. The aim of this work is to present a Life Cycle Assessment of an innovative solar technology, the Molten Salt Concentrating Solar Power (CSP) plant, developed by Italian Research Centre ENEA and able to produce clean electricity by using solar energy. The Life Cycle Assessment was carried out by means of the SimaPro7 software, one of the most used LCA software in the world. It is worth assess that these types of software are an indispensable tools for leading LCA studies. In the second part of the study the environmental performance of the CSP plant was compared with th ese of conventional oil and gas power plants.

Integration of Selective Membranes in Chemical Processes: Benefits and Examples

Integration of reaction and separation in a single unit is a powerful tool to increase efficiency and economic advantages of many chemical processes. Reactive distillation, extraction, and adsorption are well-known examples of this technological resource. Recently, a very promising solution is offered by membrane reactors (MRs).

Chapter 5 – Direct Synthesis of Methanol and Dimethyl Ether From a CO2-Rich Feedstock: Thermodynamic Analysis and Selective Membrane Application

This chapter focuses on the methanol and DME synthesis processes fed by a CO 2 -rich syngas feedstock derived from a biological process as fermentation or gasification of biomasses. The conversion of a CO 2 -rich stream allows the valorization of carbon dioxide, converting it into added high-value products such as methanol and dimethyl ether. However, a thermodynamics analysis highlights the strong negative effect that an inlet CO 2 composition has on conversion reactions and the products yielded. The solution to supporting methanol/DME production processes with high contents of CO 2 is to integrate a membrane that is selective to water and able to remove the generated steam. This approach avoids accumulation of water inside the reaction environment, thus overcoming the thermodynamic thresholds and supporting the methanol and DME generation reactions.

Enriched Methane: A Ready Solution for the Transition Towards the Hydrogen Economy

The extensive use of hydrogen as an energy vector has the potential to minimize the world’s addiction to crude oil mitigating the global warming as well as economic crisis and conflicts. Nonetheless, at least in the near term, hydrogen economy will hardly replace fossil fuels because of the high production cost, the difficulty of storing at high energy density, the lack of extensive distribution infrastructure. R&D advances do not satisfy policies, investors and consumer’s needs. The potential for methane enrichment by mixing with hydrogen is an interesting alternative to the complete replacement of conventional fuels and to the increased need of exploiting renewable energies. This solution can rapidly find a market collocation to renewable production (from gasification and steam reforming), low-cost storage and delivery through existent technologies, whereas improving the environmental impact of “methane/natural gas” applications. In this chapter, we present the application potentialities of the enriched methane in the four areas characterizing the evaluation of alternative fuels: production, storage, distribution and utilization. We present the main advances in this framework and the near perspectives indicating the enriched methane as a promising route towards the hydrogen economy and an immediate solution for the mitigation of climate changes.

Enriched Methane Production Through a Low Temperature Steam Reforming Reactor

An innovative hybrid plant, composed by a solar section for heating up a molten salt stream through a Concentrating Solar Power (CSP) plant, a chemical section for the production of 1000 Nm3/h of Enriched Methane (EM) with a 20 %vol. content of hydrogen, and an electrical section for the electricity production by means of an Organic Rankine Cycle unit (conversion efficiency = 28 %) is presented and assessed. The core of the process is the low-temperature solar steam reformer, where a feedstock composed by methane and water steam is partially converted to hydrogen. The reactor is modeled in detail, the equations set is described and commented, together with the boundary conditions. Then, the reactors’ behavior is simulated. By applying 15 reformers in parallel and imposing a Gas Hourly Space Velocity (GHSV) of 40,965 h−1, it is possible to produce a stream of EM (20 %vol. H2) equal to 1000 Nm3/h and 500 kW approximately of net electrical power output. The molten salt stream is heated up to 550 °C by the CSP plant, then it supplies the reforming process heat duty (reactor heat duty, feedstock preheating, and reactant steam generation) and, finally, it generates the electricity by exploiting its residual sensible heat. By the simulation of the reformers under industrial conditions, the feasibility of the proposed architecture is demonstrated and its potentialities are assessed.