Annarita Salladini

Reformer and membrane modules for methane conversion: experimental assessment and perspectives of an innovative architecture.

An innovative concept for steam methane reforming (SMR), based on reformer and membrane modules (RMMs), has been developed and tested to investigate its performance, in terms of feed conversion, on an industrial scale. A major benefit of the proposed RMM configuration is a shift of the chemical equilibrium of SMR reactions, achieved by removing the hydrogen produced at high temperature through the integration of highly selective palladium-based membranes, which enhances the yield of product. In this manner the process can operate at temperatures as low as 600-650 °C, compared to the 850-880 °C range used in conventional plants, and allows for the use of a low-temperature heat source. This Full Paper discusses experimental data on feed conversion at different operating parameters, gathered during 1000 h of testing, and processes these data to optimize the overall architecture, defining the maximum achievable feed conversion. An overall conversion of 59% is achieved with two-step reactions at a reforming temperature of 620 °C. A conversion as high as 90% can be obtained with a three-step architecture at 650 °C by properly extending the design parameters within reasonable limits.

Waste-to-methanol: Process and economics assessment

The waste-to-methanol (WtM) process and related economics are assessed to evidence that WtM is a valuable solution both from economic, strategic and environmental perspectives. Bio-methanol from Refuse-derived-fuels (RdF) has an estimated cost of production of about 110€/t for a new WtM 300t/d plant. With respect to waste-to-energy (WtE) approach, this solution allows various advantages. In considering the average market cost of methanol and the premium as biofuel, the WtM approach results in a ROI (Return of Investment) of about 29%, e.g. a payback time of about 4years. In a hybrid scheme of integration with an existing methanol plant from natural gas, the cost of production becomes a profit even without considering the cap for bio-methanol production. The WtM process allows to produce methanol with about 40% and 30-35% reduction in greenhouse gas emissions with respect to methanol production from fossil fuels and bio-resources, respectively.

Catalytic Partial Oxidation Coupled with Membrane Purification to Improve Resource and Energy Efficiency in Syngas Production

Catalytic partial oxidation coupled with membrane purification is a new process scheme to improve resource and energy efficiency in a well-established and large scale-process like syngas production. Experimentation in a semi industrial-scale unit (20 Nm(3)  h(-1) production) shows that a novel syngas production scheme based on a pre-reforming stage followed by a membrane for hydrogen separation, a catalytic partial oxidation step, and a further step of syngas purification by membrane allows the oxygen-to-carbon ratio to be decreased while maintaining levels of feed conversion. For a total feed conversion of 40 %, for example, the integrated novel architecture reduces oxygen consumption by over 50 %, with thus a corresponding improvement in resource efficiency and an improved energy efficiency and economics, these factors largely depending on the air separation stage used to produce pure oxygen.

Waste-to-chemicals for a circular economy: the case of urea production (waste-to-urea)

The economics and environmental impact of a new technology for the production of urea from municipal solid waste, particularly the residue-derived fuel (RdF) fraction, is analyzed. Estimates indicate a cost of production of approximately €135 per ton of urea (internal rate of return more than 10 %) and savings of approximately 0.113 tons of CH4 and approximately 0.78 tons of CO2 per ton of urea produced. Thus, the results show that this waste-to-urea (WtU) technology is both economically valuable and environmentally advantageous (in terms of saving resources and limiting carbon footprint) for the production of chemicals from municipal solid waste in comparison with both the production of urea with conventional technology (starting from natural gas) and the use of RdF to produce electrical energy (waste-to-energy). A further benefit is the lower environmental impact of the solid residue produced from RdF conversion. The further benefit of this technology is the possibility to realize distributed fertilizer production.

Natural Gas Catalytic Partial Oxidation: A Way to Syngas and Bulk Chemicals Production

© 2012 Iaquaniello et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Natural Gas Catalytic Partial Oxidation: A Way to Syngas and Bulk Chemicals Production

Reformer and Membrane Modules (RMM) for Methane Conversion Powered by a Nuclear Reactor

In the last few years, significant developments in membrane science and the vision of process intensification by multifunctional reactors have stimulated the academic and industrial research focused on membrane reactor application to chemical processes (Mendes et al., 2010, Dittmeyer et al., 2001, Basile et al., 2005a, De Falco et al., 2007). From these works, the increase of the reactants conversion above the equilibrium values appears to be possible when a reaction products at least is removed through the membrane. As stated in the following, the integration of selective membrane in a chemical process can be twofold:  directly inside the reaction environment (Integrated Membrane Reactor – IMR);  after the reaction step (Reaction and Membrane Module – RMM). In this chapter a methane steam reforming (MSR) RMM pre-industrial plant, designed and tested to investigate at an industrial scale level the plant performance, is presented. A major benefit of the proposed RMM configuration is the shift of steam reforming reactions chemical equilibrium by removing the hydrogen produced at high temperature, thanks to the integration of highly selective Pd-based membranes and enhancing the final product yield. By this way, the process can operate at a temperature as low as 600-650°C in comparison to 850-880°C needed in conventional plants, and enable the use of low temperature heat source as helium heated in a nuclear reactor. This chapter reports, firstly, membrane reactor concept, selective membrane typologies and integration strategies; then it discusses the experimental data gathered over 1000 hours of testing on an industrial pilot unit in terms of feed conversion at different operating parameters and elaborates such data in order to optimize the overall architecture, defining the maximum achievable feed conversion under different scenario of heat integration. Finally, a membrane reactor perspectives analysis, mainly focused on integration with nuclear reactors for steam reforming reactor heat duty supplying, is reported in order to understand which technical and economical targets have to be reached in the next future for a commercial diffusion. The plant discussed in this chapter, placed in Chieti Scalo (Italy), is characterized by a H2 design capacity of 20 Nm3/h and it operates with three Pd and Pd/Ag based membranes for

Waste to Chemicals for a Circular Economy

The implementation of a circular economy is a fundamental step to create a greater and more sustainable future for a better use of resources and energy. Wastes and in particular municipal solid waste represent an untapped source of carbon (and hydrogen) to produce a large range of chemicals from methane to alcohols (as methanol or ethanol) or urea. The waste to chemical process and related economics are assessed in this concept article to show the validity of such solution both from an economic point of view and from an environmental perspective considering the sensible reduction in greenhouse gas emissions with respect to conventional production from fossil fuels.

Integrating membranes into industrial chemical processes: a case study of steam reforming with membranes for hydrogen separation

Abstract: This chapter focuses on the operating experience and the results obtained from experiments carried out at a natural gas steam reformer plant integrated with Pd- and Pd–Ag-based membrane modules for hydrogen separation. The plant is based in Chieti Scalo, Italy, and was developed within the framework of an Italian research project entitled ‘Pure hydrogen from natural gas reforming up to total conversion obtained by integrating chemical reaction and membrane separation’. The first section of the chapter deals with the advantages relevant to the integration of membranes in an equilibrium reaction environment, paying particular attention to steam reforming reactions. Two different configurations are described and analyzed. The second section deals with the description of the reformer and membrane module plant in Chieti Scalo. The process scheme is presented, along with descriptions of the main sections of the plant, including reforming reactors, membrane modules and the control system. The third section reports the experimental results obtained. Attention is focused on the performance of membranes and their integration into the steam reforming plant, as well as on the performance of the catalysts used. Experimental data are discussed in order to characterize the permeability of the membranes employed and to define their long-term stability.

Chapter 13. Palladium-based Selective Membranes for Hydrogen Production

In a membrane reactor one or more chemical reactions, generally catalytically promoted, are carried out in the presence of a membrane selectively permeated by one of the reaction products. As result of a lower reaction temperature, another major advantage emerges, i.e. the possibility of a better heat integration, as the use of gas exhausts from a gas turbine or solar heated molten salts. In view of the significant potential advantages, attention hereafter is paid mostly to membrane reactor engineering focusing on the most interesting applications.Membrane integration criticism has to be carefully faced. If the selective membrane is directly integrated in the reaction environment, coupling catalyst and membrane operating conditions leads to the necessity to define a compromise optimization in order to promote both the kinetics and permeability, without damaging the membrane always requesting stringent thermal threshold. On the other hand, the membrane can be integrated externally, by an architecture which foresees reaction and separation steps in series. In this way, catalyst and membrane operating conditions are independent and their optimal operating conditions can be defined separately.It is a worthy assessment that the development of such innovative reactors requires ad hoc design criteria definition.Such a note, focused mainly on hydrogen production processes, is articulate in: Basic features of membrane reactors Open or closed architecture Heat integration strategies Case studies applications.

Steam Reforming of Natural Gas in a Reformer and Membrane Modules Test Plant: Plant Design Criteria and Operating Experience

A staged membrane reactor, called reformer and membrane modules (RMM), test plant with a capacity of 20 Nm3/h hydrogen has been designed and constructed to investigate at an industrial scale level the performance of such innovative architecture. A major benefit of the proposed RMM configuration is the shift of conversion beyond equilibrium value by removing the hydrogen produced at high temperature, thanks to the integration of highly selective Pd-based membranes. By this way, the process can operate at lower thermal level (below 650°C in comparison to 850–950°C needed in tradition plants). Moreover, a noble metal catalyst supported on SiC foam catalyst is used in order to enhance thermal transport inside the catalytic tube. This chapter reports together with preliminary operational data, the plant design criteria, the process scheme, the construction of reformers and membrane units, and the control system implemented to maximize experimental outputs. Four types of Pd-based membranes, three tubular and one planar shaped, are installed in order to compare the performance in terms of hydrogen flux permeated. The ranges of operating conditions investigated (reaction temperatures and pressures, separation temperatures and pressures, flow-rates, and sweeping gas flows) are defined; plant performance and preliminary experimental data are also reported and assessed. The 20 Nm3/h RMM installation will allow the potentialities of selective membrane application in industrial high-temperature chemical processes to be completely understood and constitutes a unique in the world.