Rewarding of extra-avoided GHG emissions in thermochemical biorefineries incorporating Bio-CCS

The incorporation of Bio-CCS, which involves an increase in investment and operating costs, would not be of interest in thermochemical biorefineries unless some economic benefit were provided. The rewarding of extra-avoided emissions encourages larger savings of GHG emissions in thermochemical biorefineries incorporating Bio-CCS. Therefore, there is a need for policies which reward of Bio-CCS incorporation, and in a broader sense, all extra-avoided emissions. In this study, we analyze how the geological storage of already captured CO₂ (i.e. the incorporation of Bio-CCS) could be rewarded, taking different policy scenarios in the EU into consideration. Since thermochemical biorefineries achieve a GHG saving above the minimum target in the EU, the sale of all extra-avoided GHG emissions (not only from the geological storage of captured CO₂) from energy carriers and chemicals is analyzed. Two different configurations of thermochemical biorefineries are analyzed: a biorefinery producing an energy carrier and a biorefinery co-producing an energy carrier and chemicals. Considering the sale of CO₂ allowances in the European Emissions Trading Scheme (EU-ETS), current prices (5–15 €/t) would not make Bio-CCS incorporation profitable. However, it would be profitable compare with current sequestration costs for conventional power plants (50–100 €/t). If the sale of extra-avoided emissions from the production of energy carriers were included in the EU-ETS, the CO₂ sequestration cost would be reduced, although not enough to enhance the process economy. If chemicals were included, the sequestration cost would decrease significantly

Balance and saving of GHG emissions in thermochemical biorefineries

In this study, a simplified methodology for the calculation of the balance of greenhouse gas (GHG) emissions and corresponding saving compared with the fossil reference is presented. The proposed methodology allows the estimation of the anthropogenic GHG emissions of thermochemical biorefineries (net emitted to the atmosphere). In the calculation of the GHG balance, all relevant factors have been identified and analyzed including multiproduction, emissions from biogenic carbon capture and storage (Bio-CCS), co-feeding of fossil fuels (secondary feedstock) and possible carbon storage in biomass-derived products (chemicals). Therefore, it is possible to calculate the balance of GHG emissions of a hypothetical thermochemical biorefinery considering different alternatives of land-use, biomass feedstock, co-feeding of fossil fuels, Bio-CCS incorporation and final use of the products. The comparison of the estimated GHG balance with the corresponding fossil reference for each product is of special relevance in the methodology since it is the parameter used in European regulation for the fulfillment of sustainability criteria in biomass-derived fuels and liquids. The proposed methodology is tested using a previously assessed set of different process concepts of thermochemical biorefineries (techno-economic analysis). The resulting GHG balance and saving are analyzed to identify uncertainties and provide recommendations for future regulation. In all process concepts, the GHG savings are above the minimum requirement of GHG emissions for 2018. In the case of incorporating Bio-CCS, cradle-to-grave negative GHG emissions are obtained. However, in order to assess the role of chemical co-production from biomass, they need to be included in future regulation

Explorando la regeneración de la mordenita en la reacción de carbonilación de dimetiléter

Dimethyl ether carbonylation (DME) to produce methyl acetate (MA) over mordenite catalysts is attracting much attention because of its high selectivity. However, acidic mordenite suffers from a fast deactivation (coking) that has not been properly studied. In the present work, we study the regeneration of the catalyst in several cycles aiming to help the future industrial application of mordenite catalysts in MA production. Both diluted and pure air have been successfully tested for the regeneration of the catalyst. The results show that 1) there is no negative effect after several regeneration cycles and 2) there is a slight improvement of catalyst productivity after the first regeneration cycle. A possible explanation to these results, which is highlighted in this work, is that the catalyst structure is not affected during regeneration while there is an initial migration of Al from the mordenite structure to extra-framework positions.Ministerio de Economía y Competitividad, BIOTER project, Proyecto I+D Retos ENE2012-31598Ministerio de Economía y Competitividad, Universidad de Sevilla, Juan de la Cierva IJCI-2017-3283

Conversion of aqueous ethanol/acetaldehyde mixtures into 1,3-butadiene over a mesostructured Ta-SBA-15 catalyst: Effect of reaction conditions and kinetic modelling

This paper studies key issues for the design of industrial ethanol to 1,3-butadiene two-step processes, focusing on the second catalytic reaction step, for which a Ta-SBA-15 catalyst was chosen as a representative of the new generation of two-step catalysts. The important practical aspects studied were: i) the effect of operating conditions and the presence of impurities (water) in the ethanol feedstock on the performance of the catalyst, ii) stability and regeneration of the catalyst, and iii) the development of a kinetic model that can be used as a tool for designing the industrial process. The results showed that there are large non-linear interacting effects between the reaction conditions (temperature, space velocity and ethanol/acetaldehyde mole ratio) which must be carefully selected to optimize the catalyst performance. When shifting from an anhydrous to an aqueous ethanol/acetaldehyde feed (7.5 wt% water), catalyst performance at high temperature barely changed while at low temperature, conversion of ethanol and acetaldehyde decreased. Water in the feed largely increased the stability of Ta-SBA-15 catalyst. Finally, a kinetic model of a fresh catalyst was developed, whose novelty lies in the use of kinetic equations that account for the effect of water in the feed on the catalyst performance.Ministerio de Economía, Industria y Competitividad CTQ2015-71427-

Aluminium(iii) dialkyl 2,6-bisimino-4R-dihydropyridinates(−1): selective synthesis, structure and controlled dimerization

A family of stable and otherwise selectively unachievable 2,6-bisimino-4-R-1,4-dihydropyridinate aluminium (III) dialkyl complexes [AlR’2(4-R-i PrBIPH)] (R = Bn, Allyl; R’ = Me, Et, i Bu) have been synthesized, taking advantage of a method for the preparation of the corresponding 4-R-1,4-dihydropiridine precursors developed in our group. All the dihydropyrdinate(−1) dialkyl aluminium complexes have been fully characterized by 1 H- 13C-NMR, elemental analysis and in the case 2’a, also by X-ray diffraction studies. Upon heating in toluene solution at 110 °C, the dimethyl derivatives 2a and 2’a dimerize selectively through a double cycloaddition. This reaction leads to the formation of two new C–C bonds that involve the both meta positions of the two 4-R-1,4-dihydropyridinate fragments, resulting the binuclear aluminium species [Me2Al(4-R-i PrHBIP)]2 (R = Bn (3a); allyl (3’a)). Experimental kinetics showed that the dimerization of 2’a obeys second order rate with negative activation entropy, which is consistent with a bimolecular rate-determining step. Controlled methanolysis of both 3a and 3’a release the metalfree dimeric bases, (4-Bn-i PrHBIPH)2 and (4-allyl-i PrHBIPH)2, providing a convenient route to these potentially useful ditopic ligands. When the R’ groups are bulkier than Me (2b, 2’b and 2’c), the dimerization is hindered or fully disabled, favoring the formation of paramagnetic NMR-silent species, which have been identified on the basis of a controlled methanolysis of the final organometallic products. Thus, when a toluene solution of [AlEt2(4-Bn-i PrBIPH)] (2b) was heated at 110 °C, followed by the addition of methanol in excess, it yields a mixture of the dimer (4-Bn-i PrHBIPH)2 and the aromatized base 4-Bn-i PrBIP, in ca. 1 : 2 ratio, indicating that the dimerization of 2b competes with its spontaneous dehydrogenation, yielding a paramagnetic complex containing a AlEt2 unit and a non-innocent (4-Bn-i PrBIP)•− radicalanion ligand. Similar NMR monitoring experiments on the thermal behavior of [AlEt2(4-allyl-i PrBIPH)] (2’b) and [Ali Bu2(4-allyl-iPrBIPH)] (2’c) showed that these complexes do not dimerize, but afford exclusively NMR silent products. When such thermally treated samples were subjected to methanolysis, they resulted in mixtures of the alkylated 4-allyl-i PrBIP and non-alkylated i PrBIP ligand, suggesting that dehydrogenation and deallylation reactions take place competitivelyMinisterio de Economía y Competitividad de España (MINECO) y los Fondos europeos FEDER-CTQ2015-68978-P y PRX14/00339United States National Science Foundation-CHE-166491

Abordagem experimental e numérica aplicada na dissolução do calcário no processo de dessulfurização de gases de combustão

Wet FGD technologies account for around 87% of FGD systems worldwide (SOUD, 2000), particularly that which u ses limestone as the absorbent reagent. This technique is widely used in large thermal power stations. The limestone reactivity is one of the parameters that most influence the yield of the FGD process. To evaluate limestone reactivity experiments were conducted in one agitated batch reactor, with pH and temperature control and CO2 sparging. With the aim of improving the design and operation of desulfurization units, many studies have been carried out to investigate the rate of limestone dissolution. This proposed model considers the grain-sized distribution of particles, composition and pH of the liquid phase. This model was validated with experimental results, allowing predicting limestone dissolution kinetics in acid pH, with a maximum error of 18%.A tecnologia de dessulfurização úmida abrange aproximadamente 87% do mercado mundial (SOUD, 2000), especialmente a que utiliza como reagente absorvente, sendo particularmente empregada em grandes centrais termelétricas. A reatividade do calcário é um dos parâmetros que mais influem no rendimento do processo de dessulfurização de gases de combustão. Neste trabalho foram realizados experimentos em um reator de batelada agitado, com controle de pH e temperatura, com borbulhamento de CO2, para avaliação da reatividade do calcário, bem como a elaboração de um modelo para simular a dissolução das partículas de calcário. O modelo proposto leva em consideração a distribuição granulométrica das partículas, sua composição e o pH da matriz líquida onde se realiza a dissolução. Este modelo foi validado utilizando os resultados obtidos experimentalmente, permitindo predizer a cinética de dissolução do calcário em pH ácido, sendo o erro máximo entre os resultados experimentais e os numéricos de 18%

Jornadas de Colaboración de Iniciativas Estratégicas (PTIs y Conexiones)

Datos técnicos: 315 minutos, color, español. Ficha técnica: Gabinete de Presidencia CSIC y Departamento de Comunicación. Emitido en directo el 14 feb 2023El próximo martes 14 de febrero, de 9:30 a 14:15 la Vicepresidencia de Investigación Científica y Técnica, organiza una Jornada en la que se buscará potenciar las colaboraciones científicas del CSIC mediante iniciativas estratégicas: las Plataformas Temáticas Interdisciplinares (PTIs) y las Conexiones.CSIC, así como poner en valor el trabajo realizado por todos los investigadores que forman parte de estas estructuras. Contará con la participación de la Presidenta del CSIC, Eloísa del Pino, representantes de las Vicepresidencias, los coordinadores científicos de las iniciativas y otros socios y colaboradores externos. Como parte de la Jornada se celebrarán tres mesas redondas en las que empresas, administraciones públicas y fundaciones compartirán sus historias de éxito alcanzadas mediante la colaboración con PTIs y Conexiones.Peer reviewe

Análisis y optimización del proceso de desulfuración de gases de combustión con agua de mar

La utilización de agua de mar como agente absorbente en sistemas de desulfuración es un método tecnológicamente más sencillo, eficiente y económico que otros actualmente en operación. Las ventajas principales que presenta son: alta eficacia de desulfurac

Hydrogen production from landfill biogas: Profitability analysis of a real case study

Hydrogen is not only considered as a cornerstone within renewable energy portfolio but it is also a key enabler for CO2 valorisation being a central resource for industrial decarbonization. This work evaluates the profitability of hydrogen production via combined biogas reforming and water–gas shift reaction, based on a real case scenario for landfill biogas plant in Seville (Spain). A techno-economic model was developed based on a process model and the discounted cash-flow method. A biogas flow of 700 m3/h (input given by the landfill biogas plant) was used as plant size and the analysis was carried out for two different cases: (1) use of already available energy sources at the industrial plant, and (2) solar energy generation to power the process. The economic outputs obtained showed that under the current circumstances, this hydrogen production route is not profitable. The main reason is the relatively low current hydrogen prices which comes from fossil fuels. A revenues analysis indicates that hydrogen from biogas selling prices between 2.9 and 5.7 €/kg would be needed to reach profitability, which are considerably higher than the current hydrogen cost (1.7 €/kg). A subsidy scheme is suggested to improve the competitiveness of this hydrogen production process in the short-medium term. A cost analysis is also performed, revealing that electricity prices and investment costs have a high impact on the total share (23–40% and 8–22%, respectively). Other potential costs reduction such as catalyst, labour and manteinance & overhead are also evaluated, showing that cutting-down production costs is mandatory to unlock the potential of hydrogen generation from biogas. Our work showcases the techno-economic challenge that green energy policies face in the path toward sustainable societies