Hydrogen is one of the most suitable energy sources from both technological and environmental perspectives for the next century, especially in the context of a sustainable global energy economy. The most common industrial process to produce high-purity (99.99+ mol%) hydrogen is to reform natural gas by a catalytic reaction with steam at a high temperature. Conventional steam-methane reforming (SMR) contributed to approximately 2.4 billion standard cubic feet per day (SCFD) of hydrogen production in the US. By 1998, the growth of SMR-produced hydrogen in the US is expected to reach 3.4 billion SCFD, with the increased demand attributed to hydrogen's use in reformulated gasolines required by the Clean Air Act. The goal of this work is to develop an even more efficient process for reforming steam and methane to hydrogen product than the conventional SMR process. The application of Sorption Enhanced Reaction (SER) technology to SMR has the potential to markedly reduce the cost of hydrogen through lower capital and energy requirements. The development of a more cost-effective route to hydrogen production based on natural gas as the primary energy source will accelerate the transition to a more hydrogen-based economy in the future. The paper describes the process, which includes a sorbent for CO2 removal, and the various tasks involved in its development.
This book investigates the development of sorption enhanced reaction processes (SERPs) with detailed modelling and simulation, design and operation of units. SERPs are processes intensified by combining adsorption and reaction, reaction and membranes or reaction/adsorption/membranes in a single unit in order to overcome thermodynamic limitations of conversion in reversible reactions. The focus here is on gas phase and liquid phase processes involving different technologies, including pressure swing adsorptive reactors, membrane reactors and simulated moving bed reactors. Emphasis is also given to presenting data and practical applications of SERP products.Sorption Enhanced Reaction Processes provides undergraduate and graduate students of chemistry and chemical engineering, researchers and industrial engineers with a clear path towards process development of SERP, whatever the area of application.
An emerging area of research and development called Sorption Enhanced Reaction (SER) has generated much interest during the last decade in the development of (a) new reversible chemisorbents for carbon dioxide in presence of steam and (b) process schemes using those materials for production of fuel-cell grade H2 from (i) natural gas by low temperature endothermic steam-methane reforming (SMR) reaction, and (ii) synthesis gas by exothermic water gas shift (WGS) reaction, with or without simultaneous production of a by-product CO2 stream for subsequent sequestration. The research is primarily driven by the advent of the hydrogen economy and the concern of global warming and ocean acidification by CO2 emission to the atmosphere . The SER concepts are based on the well-known Le Chatelier s principle that the thermodynamic limitations (product purity and conversion) of an equilibrium-controlled reaction (catalytic or otherwise) can be circumvented by carrying out the reaction in presence of a sorbent which selectively removes a reaction product from the reaction zone, thereby increasing the conversion of reactants to products and the rate of the forward reaction. The two key chemical reactions are: SMR Reaction (Endothermic): CH4 + H2O ? CO + 3 H2, WGS Reaction (Exothermic): CO + H2O ? CO2 + H2, Both reactions are equilibrium-controlled and in situ removal of CO2 from the reaction zone at the reaction conditions will benefit production of H2 in many different ways. The thermodynamics of SMR reaction is favored at higher temperatures and conventional SMR reactors are operated above 800 oC requiring expensive alloyed steel reactors. The SER concept permits drastic lowering of the reaction temperature to 450 550 oC without sacrificing the conversion of CH4 to H2, thus significantly reducing the capital and operating costs of the reactor. It also enhances the rates of the forward reactions. Furthermore, the concept (i) minimizes or eliminates carbon formation and catalyst deactivation, (ii) increases H2 product purity, and (iii) decreases the footprint of the plant by combining the reaction and product purification steps in a single unit. The thermodynamics of the WGS reaction is favored at the lower temperatures. However, conventional WGS reactors are operated in the temperature range of 250 400 oC in order to achieve an acceptable rate of reaction. The SER concept enhances the rate of WGS reaction at lower temperatures and improves the conversion of CO to H2 and product purity. It also combines the reaction and the product purification steps in a single unit. This compendium contains six comprehensive articles describing CO2 chemisorbents and SER process concepts for H2 production. They were written by six eminent research groups around the world who have direct and extensive expertise on these subjects. The following table gives the author names, affiliations, and the titles of the articles. The CO2 chemisorbents employed in these studies include materials which undergo bulk chemical reactions with CO2 as well as materials where the CO2 chemisorption is limited to the surface. The SER processes involve a multitude of variations including pressure swing adsorption (PSA) schemes, thermal swing adsorption (TSA) schemes, combinations thereof, fixed-bed and fluidized-bed operations, continuous or semi-batch operations, etc. Experimental as well as model simulations of the process performances are also reported by the authors. The paper by Rodrigues, Xiu, Li, Grande, and Oliveira from the University of Porto, Portugal describes the simulated performance of two different SER concepts for production of H2 by SMR which employ the principles of PSA and commercial hydrotalcites modified by potassium and cesium carbonates as CO2 sorbents. The PSA concepts use (i) purge with 10% H2 in N2 for regeneration and (ii) subsections with different sorbent/catalyst ratio and operating temperatures. The paper by He and Chen from the Norwegian University of Science and Technology, Trondheim, Norway provides an extensive review of CO2 acceptors for use in SER-SMR concepts for H2 production. The materials include CaO/dolomite, Li2ZrO3, Na2ZrO3 among others. The key topics include thermodynamics and kinetics of SER process using these materials, stability of the sorbents, as well as basic SER process concepts. The paper by Harrison from Louisiana State University, Baton Rouge, LA, U.S.A. reviews various SER-SMR process designs using CaO as the CO2 sorbent. The concept can lower the SMR reaction temperature by ~200 oC compared to the conventional reaction temperature. The article by Beaver, Lee, Caram, and Sircar from the Lehigh University, Bethlehem, PA, U.S.A. reviews their recent works on a novel rapid thermal swing sorption enhanced reaction concepts for (i) production of fuel-cell grade H2 by low temperature SMR and (ii) simultaneous production of fuel-cell grade H2 and pure, compressed CO2 for subsequent sequestration from synthesis gas produced by coal gasification. Simulated process performance of these concepts are presented using K2CO3 promoted hydrotalcite and Na2O promoted alumina as CO2 sorbents. The paper by Lee, Yoon, and Baek from the Korea Institute of Energy Research, Daejeon, Korea presents model parametric studies of process design variables for production of H2 using a SER-SMR concept employing CaO as the CO2 sorbent. The article by Barelli, Bidini, and Gallorini from the University of Perugia, Italy describes a model analysis of a thermo-fluid dynamic model of a fixed-bed SER-SMR reactor for H2 production and its experimental verification. We believe that the present compilation provides a state of the art research status for the subject and will form an excellent starting point for future research. We are grateful to the authors for their kind and timely participation and contributions for making this publication a reality. We also thank Dr. S. G. Pandalai, Managing Editor of Research Signpost for inviting us to prepare this special review book and providing us with all the help for its publication.
This dissertation investigates the adsorption enhanced reaction process for hydrogen production from steam reforming of methane on both the experimental and simulation studies. The studies are divided into two parts including i) the experimental studies to observe the possibility of using multifunctional catalyst synthesized by Ni impregnated on CO2 adsorbent ii) the simulation to study the influence of different K2CO3 promoted HTC sorbents on the performance of SESMR process and to analyze the effect of the operating parameters on the pre-breakthrough period.
Covers the timely topic of fuel cells and hydrogen-based energy from its fundamentals to practical applications Serves as a resource for practicing researchers and as a text in graduate-level programs Tackles crucial aspects in light of the new directions in the energy industry, in particular how to integrate fuel processing into contemporary systems like nuclear and gas power plants Includes homework-style problems
Energy and feedstock materials for the chemical industry are in increasing demand and, with constraints related to the availability and use of oil, the energy and chemical industry is undergoing considerable changes. In recent years, major restructuring has occurred in the oil, petrochemical, and chemical industry, with increasing attention devoted to the use of natural gas, methane in particular, as a chemical feedstock rather than just as a fuel. The conversion of remote natural gas into liquid fuels or other transportable chemicals is a challenge to industrial catalysis. Few processes exist so far with the major ones involving the conversion of natural gas to synthesis gas by steam reforming, CO2 reforming, or partial oxidation, followed by the syntheses of methanol, hydrocarbons (Fischer-Tropsch synthesis), or ammonia. In this book, a comprehensive overview of the field of processing natural gas is given, through a series of chapters written by leading scientists and engineers in the field. New developments are discussed and current work relevant to the area is shown by a series of recent works by researchers working in this and related fields.
Sorption Enhancement of Chemical Processes, Volume 51 compiles the latest, state-of-the-art progress in the area of sorption enhanced processes. Topics in this updated volume include Sorption-enhanced water-gas-shift and steam methane reforming, CO2 sorbents for sorption enhanced steam reforming, Reactor design for Sorption Enhanced Reforming using Ca-Cu chemical loops, Sorption-enhanced reaction with Simulated Moving Bed reactor (SMBR) and PermSMBR technologies, and the Process design and Technoeconomic assessment of sorption enhanced systems. This series contains contributions from leading scientists on the topics presented, providing tactics on a multiscaling approach, from materials, to reactor, to process design. Contains reviews by leading authorities in their respective areas Presents up-to-date reviews of sorption enhancement of chemical processes Includes a broad mix of U.S. and European authors, as well as academic, industrial and research institute perspectives
Water Gas Shift Reaction: Research Developments and Applications outlines the importance of hydrogen as a future fuel, along with the various hydrogen production methods. The book explains the development of catalysts for Water Gas Shift (WGS) reaction at different temperatures and steam/CO ratios, and also discussing the effect of different dopants on the WGS activity of iron oxide and the promotion and inhibition roles of the dopants on the WGS activity of iron oxide are explained. In addition, the book describes extensive characterization of modified ferrite catalysts, especially with Mossbauer spectroscopy and its advantage in understanding properties of metal doped ferrite catalysts, the exact dopant location, and its effect on electron hopping capability and WGS activity of Fe redox couple. Outlines the importance of the Water Gas Shift Reaction and its application for hydrogen production Provides detailed information on potential catalysts, their development, and their pros and cons, giving the reader insights on how modified ferrite catalysts work at different temperatures and different steam to CO ratios Reviews hydrogen technology, its current importance, and production methods Presents a clear presentation of the topics with many graphics and tables Offers basic and advanced knowledge of catalysts characterization instrumental techniques
