Antonio Ricca

Performances analysis of a compact kW-scale ATR reactor for distributed H2 production

The distributed production of hydrogen takes on a growing consensus among the different methods for feeding fuel cells. The auto-thermal reforming of hydrocarbons is a candidate as the best method for producing hydrogen on a small scale. Since auto-thermal reforming reactor is fed with hydrocarbon, water and air, their mixing may play a fundamental role on the final process performances, by influencing hydrocarbon conversion, reaction selectivity, and hydrogen production. To obtain a very compact reaction system, reactants pre-heating and products cooling were realized in a special heat exchange system, fully integrated in the reactor. To study the reaction trend along the catalytic bed, a multipoint analysis system was set-up, allowing to monitor both temperature and composition in several points of catalytic bed, and then in several space velocity conditions. The preliminary tests showed very short start-up time, and fast response to the feed variations, confirming that the proposed reaction system is an interesting solution for distributed and non-continuous hydrogen production.

Compact Multi-fuel Autothermal Reforming Catalytic Reactor for H2 Production

Distributed hydrogen production to feed fuel cells needs compact and versatile reforming system: ATR reaction assures compactness and process self-sustainability. The aim of this work is to realize and test a thermally integrated catalytic reactor able to realize the ATR of gaseous and liquid hydrocarbons. Heat recovery from reaction products for pre-heating of reactants allows to feed reactants at room temperature. Preliminary experimental results performed with the integrated multi-fuel reactor showed that the system is very fast to reach the steady conditions, with a very high thermal exchange efficiency, and a good approach to the equilibrium gas phase composition at the reactor outlet in terms of adiabatic temperature, hydrocarbon conversion and hydrogen production.

Catalysts for the Intensification of the Water Gas Shift Process

Nowadays the Water Gas Shift process (WGS) is performed in two stages, a first step at high temperature (HTS), carried out at 623–873 K, and a low temperature step (LTS) at 423–573 K, to reach a favorable thermodynamic equilibrium condition. This kind of configuration is expensive and requires complex operative conditions, so to make preferable process intensification. This could be achieved through the development of new structured catalytic formulations, characterized by enhanced thermal transfer properties, able to improve the heat distribution along the catalytic bed. For this purpose the most promising catalytic systems are precious metal based supported on open cells metallic foam carriers. In this paper we report a preliminary study on the preparation and the evaluation of differently-supported Pt-based catalysts, as promising precursors in the preparation of structured catalysts for the process intensification of WGS reaction.

Comparative studies of low temperature water gas shift reaction over platinum based catalysts

Water gas shift reaction (WGS) is normally performed in a two-stage process, a first stage at high temperature (HTS) conventionally carried out at 623 873 K on Fe/Cr-based catalyst, to take advantage from a fast reaction, and a second stage at low temperature (LTS) at 423 573 K on Cu/Zn-based catalysts, to reach a favourable thermodynamic equilibrium condition. A single-stage process involves at the same time a cost reduction in plant setup as well as operative conditions; however at the moment, due to the lack of efficient catalytic systems the one-stage WGS systems is not widely diffused. Noble metals arise today as a promising solution in this direction, so in this work great attention was focused on the preparation and testing of differently-supported Platinum-based catalysts.

High Thermal Conductivity Structured Carriers for Catalytic Processes Intensification

Process intensification is conceived as a way to optimize fixed and operating costs in an industrial plant. It is not only related to a reduction of the size of equipments, but also to the change of the production method, by enhancing both chemical that physical aspects of the process. In particular, when there has to deal with exothermic equilibrium reactions, such as the Water Gas Shift, the main problem is that the conversion is limited by the kinetics at the inlet of a catalyst bed, because temperature is low, and is thermodynamically limited at the outlet, because in the adiabatic reactor temperature raises, lowering the equilibrium value. A good solution would be the use of a high conductive carrier, able to redistribute the heat of reaction along the catalyst bed. The aim of this work was to study the heat transfer phenomenon on structured carriers such as open cell foams, by estimating also the thermal properties by a mathematical model elaborated for the heat transfer system.

Structured catalysts for methane auto-thermal reforming in a compact thermal integrated atr reformer

Hydrogen and fuel cells combination is the most viable answer to the antithetic problems of growing energy demand and environmental pollution reduction. Due to the well note difficulties in H2 transport and storage, distributed H2 production results the most promising solution, so very compact and small size production plants are required. To this goal, hydrocarbons ATR reaction assures a self-sustaining process and high reactor compactness, resulting as the best method for distributed H2 production to couple to a fuel cell system. In spite of the increasing interest in renewable sources, due to the low costs and the widespread existing delivery pipelines, fossil fuels reforming still remain the best choice in a transition period towards hydrogen based economy. In this work a compact catalytic reactor was analyzed for the ATR of CH4 as natural gas surrogate. Structured catalysts (commercial honeycomb and foam monoliths) performances in CH4 processing were studied. In reactor design, great attention has been paid to the thermal integration, in order to obtain a total self-sustainability of the process avoiding additional external heat sources, and improve the plant compactness. Through an heat exchange system integrated in the reactor, water and air stream are preheated by exploiting the heat from exhaust stream, allowing to feed reactants at room temperature as well as cooling product stream at a temperature suitable for further purification stages (WGS, PROX). In order to have a very comprehensive process analysis, temperatures and composition were monitored in 6 point along the catalytic bed. The influence of catalytic system geometry as well as thermal conductivity in the process performances was also analysed. Preliminary tests showed high thermal system efficiency, with a good hydrocarbon conversion at different operating conditions for both catalyst typologies.

Bimetallic Pt and Ni based foam catalysts for low-temperature ethanol steam reforming intensification

The increasing world power demand is driving scientific interest toward the research of alternative energy sources. As energy production from fossil fuels is limited by both reduced availability and pollutants emissions, H2 from renewable feed-stocks (i.e. bioethanol) appears a good clean chance, especially for fuel cells. In this paper, the performances of ceria and ceria-zirconia supported bimetallic powder and foam catalysts in the low temperature range (300-600 °C) Ethanol Steam Reforming reaction were investigated with the aim to highlight the improved heat transfer properties of the structured samples. Two different reactor configurations were employed: catalytic powders were tested in both an annular and a tubular reactor and the hollow one was also used for foam catalysts. SiC foam catalysts, by exploiting the high thermal conductivity of the support, could reduce heat transfer resistance, thus assuring very interesting results in terms of both activity and stability. Moreover, the role of catalytic support was studied and CeO2-ZrO2 based catalysts were found more suitable for the desired reaction.

Methane steam reforming intensification: Experimental and numerical investigations on monolithic catalysts

Methane steam reforming is still the most economical route for hydrogen production. It generates hydrogen for refining processes, food industry, and recently for fuel cell applications. Recent studies focused on the application of structured catalysts in mass transfer limited-reactions indicated that there are potentially several advantages for monolithic reactor as compared to the packed reactors such as, especially in terms of lower pressure drop and better mass and heat transfer performances. So highly thermal conductive honeycomb structures were proposed as catalyst supports to enhance the heat and material transfer properties of the final catalysts. This work focuses on the experimental testing of the methane steam reforming reaction performed on a Ni-loaded SiC monolith packaged into an externally heated tube. In particular, the two flow configurations of Flow Through and Wall Flow were investigated and compared, the effect of a washcoat deposition was evaluated. The experimental tests indicate that the Wall Flow configuration may overcome the fixed-bed reactor problems, yielding a more uniform temperature distribution and more effective mass transport.

High Conversion of Styrene, Ethylene, and Hydrogen to Linear Monoalkylbenzenes

1-Alkylbenzenes as a precursor of surfactants, can be produced from ethylene, styrene, and hydrogen. These intermediates, lacking tertiary carbons, are environmentally more benign than commercial ones that bear the aromatic ring linked to an internal carbon of the aliphatic chain. The one-pot synthesis of highly linear 1-alkylbenzenes (LABs) through the homogeneous catalysis of olefin poly-insertion from cheap and largely available reagents can be carried out with a high turnover and selectivity. A purposely designed reactor that allows for the fine control of the three components feed, along with temperature, plays a key role in this achievement. A turnover of 194 g of LABs per mmol of catalyst per hour can be obtained with the simultaneous removal of polyethylene as a by-product.

State of the Art of Conventional Reactors for Methanol Production

Abstract Because it is involved in the production of a wide range of added-value chemicals, methanol is one of the most important compounds in the industrial chemistry field. The significant thermodynamic limitations related to methanol synthesis via syngas conversion has intensified interest in this process. Starting with the development of the BASF process at the beginning of the 20th century and the ICI process, introduced in the 1960s, many schemes have been proposed for the overall optimization of the process. This chapter aims to explore the methanol synthesis process and the most relevant technologies available in the methanol industry.