• Energy Research
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A techno-economic analysis of a natural gas combined cycle integrated with a pre-combustion CO2 capture process based on the Ca-Cu process has been carried out. An extensive calculation of the balances of the entire power plant has been done, including the results obtained from a 1-D pseudo homogeneous model for the fixed bed reactors that compose the Ca-Cu process. Moreover, a methodology developed by the authors is here presented for calculating the cost of the electricity produced and of the CO2 avoided. This methodology has been used to perform the economic analysis of the Ca-Cu based power plant and to optimize the size of the Ca-Cu reactors and the pressure drop in critical heat exchangers. An electricity cost of 82.6 €/MWh has been obtained for the Ca-Cu based power plant, which is 2.2 €/MWh below the benchmark power plant based on an Auto Thermal Reformer with an MDEA absorption process for CO2 capture. The improved performance of the Ca-Cu based power plant in terms of electric efficiency and reduced capital cost expenditure is the reason for the reduced electricity costs. Moreover, a lower cost of CO2 avoided is also obtained for the Ca-Cu plant with respect to the benchmark (80.75 €/tCO2 vs. 85.38 €/tCO2), which features 89% of CO2 capture efficiency.

Metallic membranes have been studied by several research groups during the last 40 years. Most of the research has been focused on developing stable membranes able to achieve high flux and high permselectivity. The vast majority of proposed applications lie on hydrogen separation through Pd-based membrane. H2 separation is a very important process in the energy and chemical industry since several applications require H2 at different purity. Therefore, the integration of metallic membrane and membrane reactors has been widely studied and compared with the current technology form a technoeconomic point of view. Several application areas among industries can take benefit from the application of membrane, where energy and environmental sustainability, such as the reduction of CO2 emissions, still represent a major concern. This chapter aims to summarize some of the most relevant research works which have been published recently (<10 years) on energy analysis and economic performance of a Pd-based membrane reactor for pure H2 separation. The analysis includes the use of different feedstocks, such as natural gas, coal, bio-based gas, and alcohol, as well as other chemicals.

Highly efficient pre-combustion systems are sustainable alternatives for producing hydrogen with reduced carbon footprint. The Ca-Cu looping process is a novel CO 2 capture process that combines Sorption Enhanced Reforming (SER) for the production of (almost) pure H 2 with a Cu/CuO redox cycle to regenerate the CO 2 sorbent with a low energy penalty and potential reduction in capture cost. Over the last few years, the Ca-Cu looping process has seen noticeable progresses in its development and has recently been demonstrated up to TRL4/5 within the Ascent EU project, under conditions that are relevant for a range of industrial applications. This work reviews the most recent achievements and open gaps of knowledge in the development of this emerging process, focusing on experimental validation performed in lab-scale fixed bed reactors and on techno-economic assessment of the application in industrial plants for hydrogen, ammonia and steel production.

Nowadays, nearly 50% of the hydrogen produced worldwide comes from Steam Methane Reforming (SMR) at an environmental burden of 10.5 tCO2,eq/tH2, accelerating the conse- quences of global warming. One way to produce clean hydrogen is via methane pyrolysis using melts of metals and salts. Compared to SMR, significant less CO2 is produced due to conversion of methane into hydrogen and carbon, making this route more sustainable to generatehydrogen.Hydrogenisproducedwithhighpurity,andsolidcarbonissegregatedand deposited on the molten bath. Carbon may be sold as valuable co-product, making industrial scale promising. In this work, methane pyrolysis was performed in a quartz bubble column using moltengallium as heat transfer agent and catalyst. Amaximumconversion of91%was achieved at 1119 ?Candambient pressure, witharesidence timeofthe bubbles in the liquid of 0.5 s. Based on in-depth analysis of the carbon, it can be characterized as carbon black. Techno-economic and sensitivity analyses of the industrial concept were done for different scenarios.Theresultsshowedthat, ifco-productcarbonissaleableandaCO2taxof50europer tonne is imposedtotheprocesses, themoltenmetaltechnologycanbecompetitivewithSMR.

Gas Switching Combustion (GSC) is a promising new process concept for energy efficient power production with integrated CO2 capture. In comparison to conventional Chemical Looping Combustion (CLC) carried out in interconnected fluidized beds, the GSC concept will be substantially easier to design and scale up, especially for pressurized conditions. One potential drawback of the GSC concept is the gradual temperature variation over the transient process cycle, which leads to a drop in electric efficiency of the plant. This article investigates heat management strategies to mitigate this issue both through simulations and experiments. Simulation studies of the GSC concept integrated into an IGCC power plant show that heat management using a nitrogen recycle stream can increase plant efficiency by 3 percentage points to 41.6% while maintaining CO2 capture ratios close to 90%. Reactive multiphase flow simulations of the GSC reactor also showed that heat management can eliminate fuel slip problems. In addition, the GSC concept offers the potential to remove the need for a nitrogen recycle stream by implementing a concentrated air injection that extracts heat while only a small percentage of oxygen reacts. Experiments have shown that, similar to nitrogen recycle, this strategy reduces transient temperature variations across the cycle and therefore merits further investigation.

Syngas fermentation is a biochemical pathway to produce ethanol and has been commercialized successfully. The economic viability of this process could be further improved to become more competitive in the existing ethanol market. Improving gas utilization is the key, and can be done by recycling the unreacted syngas. This work is an early-stage techno-economic assessment of recycling in producing ethanol from Basic Oxygen Furnace (BOF) gas. Economic viability is measured in terms of Relative Competitive Percentage (RCP) and is a measure of closeness to the current market. Two scenarios, firstly a once-through process, and secondly a process with recycling (0.9 split ratio: recycle/purge) of gas is considered. None of them showed a positive RCP as compared to the current ethanol market. Comparing these scenarios, beyond the single pass conversion of 60%, the additional production costs due to recycling become dominating and lead to a lower RCP compared to once-through systems.