http://hdl.handle.net/10366/138521 2026-04-30T11:25:50Z 2026-04-30T11:25:50Z Luceño Sánchez, José Antonio Martín Martín, Mariano http://hdl.handle.net/10366/169667 2026-02-10T08:20:14Z 2018-01-01T00:00:00Z

[EN]This work presents a two-stage optimization procedure for the conceptual design and operation of A-frame dry cooling systems for concentrated solar power facilities. First, the optimal geometry of the A-frame including sizing, number of fans and blade geometry, and unit parameters such as pipe length, configuration and number is determined. Finally, the operation of the system over a year for minimum energy consumption is computed. The geometry problem is formulated as a mixed-integer non linear programming (MINLP) problem. A tailor-made branch and bound algorithm is used to solve the complex non-linear programming sub-problems. The second problem consists of a multi-period MINLP. A fixed geometry is used to evaluate the usage of fans over time. The solution suggests an apex angle of 63°, one row of 75 pipes of 13.5 m long with a diameter of 3.3 mm, and 4 fans are used but they only operate at full capacity during summer. This design allows reducing the energy required by 20% by using the appropriate pipe configuration and number. The unit consumes around 4% of the energy produced by the CSP plant that serves. It is a promising result that can be affected by plant layout and ground availability.

2018-01-01T00:00:00Z Lozano-Santamaria, Federico Luceño Sánchez, José Antonio Martín Martín, Mariano Macchietto, Sandro http://hdl.handle.net/10366/168230 2026-01-21T11:54:10Z 2020-01-01T00:00:00Z

[EN]The operation performance of air-coolers in concentrated solar power plants decays due to particulate deposition on heat transfer surfaces. The deposition process can be seen as a stochastic phenomenon. A modelling approach is proposed to capture the uncertainty and the effect of extreme events, such as sandstorms, affecting the performance of plants located in dry places through dust or sand deposition on the air coolers. A case study of a concentrated solar power plant located in Dubai is analysed. Sandstorms generate acute and drastic fouling of the air coolers, and this is modelled as a stochastic process using historical aerosol dispersion data. Ten scenarios are generated by sampling the probability distribution of sandstorms occurrence and intensity. The optimal operation (cleaning schedule and airflow profiles) of the air coolers is established using Benders decomposition to solve the resulting large-scale mixed integer non-linear programming problem. The results of the stochastic scenarios demonstrate that substantial savings of $ 0.6 M − $ 2.7 M per year are achieved by the optimal operation. Cost is minimized by a combined reactive and proactive cleaning policy which accounts for the frequency, intensity and seasonal variability of sandstorms, in addition to the variability on local radiation and weather conditions.

2020-01-01T00:00:00Z Luceño Sánchez, José Antonio Martín Martín, Mariano http://hdl.handle.net/10366/168228 2026-01-21T11:54:53Z 2019-01-01T00:00:00Z

[EN]This work presents a parametric programming framework for the optimal design and operation of systems with performance loss over time. A two-stage procedure is proposed. The unit is designed for the operating conditions just before maintenance. In a second stage, a multiperiod problem is solved for the optimal the operation of the unit over time including cleaning costs. The minimum operating cost as a function of the cycle length determines the operating cycle and the unit design. The methodology is applied to A-frame cooling systems under fouling conditions, where fouling affects the pressure drop and the global heat transfer coefficient. The sigmoidal deposition profile results in an optimal cycle time of 8 years. This design allows reducing the energy required to around 4% of the energy produced by the concentrated solar power plant. It is a promising result that can be affected by plant layout and ground availability.

2019-01-01T00:00:00Z Hernández Blázquez, Borja Martín Martín, Mariano http://hdl.handle.net/10366/163046 2026-01-21T11:55:39Z 2022-01-19T00:00:00Z

[EN] This work presents the development of a reduced order compartment model for a counter-current spray dryer. The compartment model is formulated using adaptable compartments and introducing the use of correlations based on dimensionless groups. These correlations can capture the mean residence time they but are unable to reproduce the variance of the entire residence time distribution (RTD). Limitations are also observed in the evaluation of internal fluxes. The application of these correlations to a specific zone requires the inclusion the geometrical modifications in any part of the unit. A small internal modification in one geometry not only modifies a zone, but also influences the remaining regions so that the zones cannot be independently scaled-up. The methodology is complemented with an analysis of the RTD showing that most of the dispersion generated takes place in the bottom cone.

2022-01-19T00:00:00Z Hernández Blázquez, Borja Martín Martín, Mariano http://hdl.handle.net/10366/163043 2026-01-21T11:56:35Z 2016-05-18T00:00:00Z

[EN]We optimized the operation of the process thatreforms biogas with CO 2 and/or steam for the production ofmethanol using a mathematical optimization approach. Theraw biogas is cleaned up before reforming. Part of the biogas isused to provide energy for the process. Next, the unreactedhydrocarbons and CO 2 are removed. Subsequently, syngascomposition may be adjusted, using either water gas shiftreaction or membrane-pressure swift adsorption. Finally,methanol is synthesized. The process is modeled using massand energy balances, chemical and phase equilibria, and rulesof thumb. The problem is formulated as an NLP problem with simultaneous heat integration for the optimal biogas compositionand methanol production. Two objective functions are considered: a simplified production cost and an environmental onedeveloped based on carbon footprint. Biogas is expected to have around 50−52% of CH 4 and 45−47% of CO 2 , depending on theobjective function. The production cost of methanol is $1.75/gal, for a plant size that uses 10% of the potential biogas to beproduced in Madrid, Spain, with an investment of $46 MM.

2016-05-18T00:00:00Z Sánchez García, Antonio Blanco, Elena C. Martín Martín, Mariano http://hdl.handle.net/10366/162154 2025-04-30T20:45:43Z 2024-11-01T00:00:00Z

[EN] Methanol and ammonia emerge as two of the most important energy carriers in a new decarbonized society. In this work, a systematic assessment of the power generation based on these chemicals is performed using two different alternatives: direct utilization as green fuels in fuel cells or as carriers for hydrogen. Despite the need for a previous stage for hydrogen production, the use of these chemicals as hydrogen carriers demonstrates higher efficiencies (around 40%), mainly due to the higher degree of maturity of the hydrogen fuel cells. This is reflected in the cost of electricity for the different alternatives with around 700 €/MWh for hydrogen carrier options and about 1200 €/MWh for the direct utilization as green fuels. Compared to hydrogen, the use of methanol or ammonia has a higher electricity production cost. However, future improvements in the efficiency of fuel cell units could convert these fuels is competitive options. In addition, for different scenarios combining transportation and power generation, methanol and ammonia emerge as technically and economically feasible alternatives, especially for distances over 3000 km. Consequently, both hold a pivotal role in addressing the challenges associated with hydrogen within a future energy systems characterized by high renewable penetration.

2024-11-01T00:00:00Z Hernández-Camacho, Nereyda Vanessa Gómez-Castro, Fernando Israel Ponce-Ortega, José María Martín Martín, Mariano http://hdl.handle.net/10366/162151 2025-04-30T20:45:43Z 2024-09-01T00:00:00Z

[EN] Methanol is one of the most important chemical compounds, as it is the basis for producing a wide variety of derivatives. Its production through fossil sources such as natural gas in countries like Mexico is not entirely viable due to the fluctuations in the availability of this resource. The use of renewable sources to produce methanol represents an interesting area of opportunity to reduce the dependence on a single raw material. This work proposes the design of the methanol supply chain in Mexico using residual materials, finding a solution with the best compromise between profit, social impact, and CO2 emissions. The solution with the best compromise corresponds to a profit of 7,334,100 USD/y, a marginalization index of 2592.536 and CO2 emissions of -0.021 Mt/y. This solution has 8 different types of raw materials, 18 process plants and the use of three processing technologies: gasification, anaerobic digestion, and catalysis from CO2.

2024-09-01T00:00:00Z Cifuentes García, Roberto Galán, Guillermo Martín Martín, Mariano http://hdl.handle.net/10366/162148 2025-04-30T20:45:43Z 2024-07-01T00:00:00Z

[EN] The defossilization of household heating systems is one of the paramount goals of renewable energy, where pellets are regarded as a promising option. A multiscale techno-economic analysis is performed to determine first the raw material yield to pellets as well as estimating CAPEX and OPEX as a function of the biomass processed. Next, the location of the facilities is evaluated in the agricultural counties of Castilla y León through the formulation of an MILP facility location problem, including economic, social, and environmental objectives. The lignocellulosic materials considered are pinewood, eucalyptus wood, corn stover, and switchgrass. For substituting the natural gas-powered boilers in towns with over 500 inhabitants, 860,000 t/yr of pellets will be necessary. 98.1% substitution is achieved deploying 13 pellet plants, 11 based on pinewood and 2 on corn stover, representing 26.4% of the resources available and it is necessary to invest 164.8 M€ with an annual profitability of 133.0 M€. The emissions substituting these boilers are reduced by 94.8%. Switchgrass is studied separately as it is not currently grown in Castilla y León, although, its introduction would decrease the OPEX from 127.5 €/t to 63.9 €/t while the social and environmental impact is adversely affected.

2024-07-01T00:00:00Z Martín Martín, Mariano Sánchez García, Antonio http://hdl.handle.net/10366/162145 2025-01-21T11:01:35Z 2024-06-01T00:00:00Z

[EN] Renewable ammonia can be the path to decarbonization of food, chemicals, and the transport system. While lately, electrochemical hydrogen and air separation are gaining support, biomass-based ammonia can provide an alternative to contribute to green ammonia deployment with possible synergic with the current ammonia facilities. Different processing paths have been considered, depending on the wet content of the biomass. Wet biomass yield to ammonia is low, but it is more interesting as a waste management procedure. Biomass gasification has attracted most of the attention and results in promising ammonia production prices using technologies already in the toolbox of the process industry. The combination of ammonia and urea production solves one of the most significant challenges in biomass-based ammonia, the released CO2. These integrated facilities allow for the full utilization of biomass in the green chemical industry.

2024-06-01T00:00:00Z Prieto-García, María Hernández Blázquez, Borja Sanz, Carlos Marcos, Jennifer Sánchez, Jose L. Grondona, Isabel Martín Martín, Mariano http://hdl.handle.net/10366/162121 2025-04-30T20:45:43Z 2024-03-01T00:00:00Z

[EN] This work introduces a compartment model based on a discreteelement method (DEM) model. The DEM model determines the residence times(RTs) of particles in the active (in contact with air) and passive zones. Theextracted RT is combined with the heat and mass transfer models into acompartment model, where particles are modeled by employing a populationbalance. Heat and mass transfer models contain efficiency coefficients that aremodeled with surrogates generated from a reduced set of experiments. Theresulting surrogate models are validated with additional experiments in anindustrial facility. It accurately reproduces the heat and mass transfer in the dryer(±10% of relative error in temperature prediction) and provides a guess of thedistribution of the properties of the particles (e.g., moisture content andtemperature) across particle sizes and locations within the dryer.

2024-03-01T00:00:00Z Del‐Mazo‐Alvarado, Octavio Prieto, Carlos Sánchez, Antonio Ramírez‐Márquez, César Bonilla‐Petriciolet, Adrián Martín Martín, Mariano http://hdl.handle.net/10366/162117 2025-07-10T10:58:30Z 2024-03-01T00:00:00Z

[EN] Glycerol carbonate (GC) is one of the most attractive green chemicals involved in several applications such as polymer synthesis, e. g., the production of polyurethanes and polycarbonates. This relevant chemical can be produced, in a green way, using CO2 (from carbon capture) and glycerol (a byproduct from biodiesel manufacturing). Therefore, in this work, a comprehensive analysis of the GC production process is conducted based on the following synthesis route: urea-dimethyl carbonate-GC using carbon dioxide and glycerol as the main raw materials where the synthesis pathway was efficiently integrated using Aspen Plus. A techno-economic analysis was performed in order to estimate the required capital investment and operating cost for the whole GC process, providing insights on individual capital cost requirements for the urea, dimethyl carbonate, and GC production sections. A total capital cost of $192.1 MM, and a total operating cost of $225.7 MM/y were estimated for the process. The total annualized cost was estimated as $1,558 USD/t of GC produced, competitive with current market price.

2024-03-01T00:00:00Z Fonseca-Pérez, Rosa María Almena, Alberto Ramírez-Márquez, César Bonilla-Petriciolet, Adrián Martín Martín, Mariano http://hdl.handle.net/10366/162115 2025-04-30T20:45:44Z 2024-02-01T00:00:00Z

[EN] A systematic techno-economic analysis for the comparison of different routes for grape seed oil extraction was performed, which included hexane extraction as benchmark process, and the use of supercritical fluids (SC), specifically SC-CO2 and SC-CO2+ethanol as co-solvent. The processes have been modeled rigorously using Aspen Plus. The results show that the use of hexane is the most efficient (13.06 % recovery) and, only by using a co-solvent together with SC-CO2, the yield is similar (12.98 %). However, the cost increases from 6.31 USD/kg of extracted grape oil to 8.61 USD/kg of oil extracted, even though it is cheaper than the use of SC-CO2 alone. The investment cost is almost twice using the co-solvent compared to the traditional one ($9.72 MM vs $4.95 MM). SimaPro has been used to perform the lifecycle assessment (LCA). Similar results are found when the LCA analysis is performed as long as the energy mix is the current one. The high energy consumption of SC based systems results in high carbon emissions. However, combining electrification and renewable energy allowed the SC-CO2+ethanol system to reduce by 25 % the CO2 emissions per kg of oil produced by the hexane system. The economic evaluation performed provides the estimation of the CAPEX and OPEX for each alternative.

2024-02-01T00:00:00Z Roldán-San Antonio, José E. Amador, Carlos Martín Martín, Mariano Blyth, Kevin Mago, Vania Cristina Croce Bowman, Joe http://hdl.handle.net/10366/162113 2025-04-30T20:45:44Z 2024-01-01T00:00:00Z

[EN] A mechanistic model to evaluate the stability of amylase and protease under food stain removal conditions has been developed. The mechanism was determined identifying the significant factors for each enzyme based on response surface methodology. The amylase stability was jeopardized by the deprotonated peracid-based bleach, the interaction pH–temperature, and the protonated peroxide-based bleach promoted by manganese-based bleaching catalyst. The stability of the protease decreased in presence of protonated peracid-based bleach, acid-base equilibria species from peroxide-based bleach as well as temperature and pH. This work integrates the main mechanisms based on non-linear differential equations for each enzyme. In addition, a kinetic dissolution model was included for the enzymatic spherical particles. The models were validated, obtaining a determination coefficient of 0.84 and 0.90 for amylase and protease respectively for the training data set. For the validation set, a determination coefficient of 0.91 and 0.90 were obtained for amylase and protease, respectively.

2024-01-01T00:00:00Z Galán, Guillermo Martín Martín, Mariano Grossmann, Ignacio http://hdl.handle.net/10366/162110 2026-01-21T11:58:01Z 2024-01-01T00:00:00Z

[EN]This work evaluates a systematic comparison between the production of methanol and methane using CO2 and renewable hydrogen. CO2 is captured from point and dilute sources using aqueous MEA solutions and a conventional DAC process. Hydrogen is obtained through water electrolysis, powered by PV panels and wind turbines. First, a techno-economic evaluation is developed to detail the characteristics of the production facilities and the renewable energy systems. Finally, a Facility Location Problem (FLP) is developed to determine the centralized and decentralized CO2 use across Spain. This supply network is formulated as a mixed-integer linear programming (MILP) problem, selecting the optimal amount of CO2 to capture, the number and location of the facilities, the distribution of the PV panels for a fixed available area in the territory, and the number of wind turbines across the 47 Spanish peninsular provinces. Methanol is the selected product, with prices between 1,000–2,600 €/tMethanol. MEA solutions are preferred over DAC. Methane production is also considered through decentralized CO2 capture due to abundant CO2 availability and high transportation costs. A sensitivity analysis was performed, obtaining prices from 18.97 to 20.36 €/MMBTU to 8.90–9.09 €/MMBTU in the years 2022 and 2050, covering 5 times the methane production for that period. The implementation of carbon taxes could lower methane prices to around 2–3 €/MMBTU by 2050, aligning closely with natural gas prices.

2024-01-01T00:00:00Z González-Núñez, Sofía Martín Martín, Mariano Amador, Carlos http://hdl.handle.net/10366/162109 2026-01-21T11:58:54Z 2024-02-01T00:00:00Z

[EN]An integrated facility to produce surfactants from manure and CO2 is conceptually designed avoiding the use of external chemicals. Cow and pig manure is anaerobically digested to produce biogas and digestate. The biogas is used to produce hydrogen via reforming. The digestate provides the nutrients for algae growing. From the algae, lipids and starch are extracted and broken down to produce oil, and glucose. Finally, the alkyl polyglucoside surfactant (APG) is produced from hydrogenated oil and glucose. The yield of the facility reaches 0.08 kgAPG/kgmanure (0.47 kgAPG/kgalgae). A facility of 252 kt/yr of APG, consumes 17.7 MW of thermal energy and steam and 7.9 MW of electricity, capturing 788 kt/yr of CO2. The investment adds up to 196 M€ with a production cost of 0.17€/kgAPG. A scale down study is also developed. Current market price of APG can be achieved processing the waste of over 1.4 k cows and 11.4 k pigs.

2024-02-01T00:00:00Z Galán Iglesias, Guillermo http://hdl.handle.net/10366/159633 2025-08-29T10:55:16Z 2024-01-01T00:00:00Z

[EN]The significant advancements in technologies and production processes within a highly dynamic and competitive market landscape are driving the requirements for optimizing production processes and enhancing the design and distribution of high-value-added products. This aspect is increasingly recognized as crucial. The pursuit of greater efficiency, leading to enhanced economic, social, and environmental benefits, has become a cornerstone. Achieving this entails meticulously designing specific products or processes within facility locations and establishing robust supply chains. Adopting a global perspective on the entire operation enables leveraging potential advantages deriving from collaborative efforts, with an associated reduction of distribution times, operational costs, and enhanced process integration. However, addressing complex challenges like managing multiscale variables poses significant barriers. Nonetheless, greater process integration holds promise for improving waste recovery, distribution, and treatment, with the aim of optimization. As a response, this thesis addresses the issue by employing diverse technologies rooted in the integrated design of processes and products, alongside facility location and the establishment of the supply chain. It particularly focuses on acquiring high-value-added products through waste recovery using a multi-scale and multi-period approach. To facilitate optimization, a range of algorithms is applied, including data analysis, linearization, problem reformulation, and multilevel optimization. This comprehensive approach aims to enhance process management and promote sustainability. Based on the findings, a product and process design approach has been employed for the optimization and integrated design aimed at sustainable production of a fuel additive, ETBE, being able to optimize the biomass to be used. This involves primarily utilizing ethanol and i-butene sourced mainly from switchgrass, with an annual production target of 90 ktETBE at a production cost of 0.61 €/kgETBE. Furthermore, an integrated system has been devised for the production of xylitol and sorbitol from lignocellulosic biomass, such as switchgrass and corn stover. This initiative aims to enhance the biomass selection, process efficiency and reducing the production costs, achieving annual production volumes of 145 ktXylitol and 157.6 ktSorbitol, with a production cost of 0.28 €/kg. Apart from biomass, CO2 can also be captured via human-made technologies. In terms of CO2 capture, utilization, and valorization, the integrated design, along with careful consideration of facility location and size, as well as multiperiod analysis, facilitates the identification of optimal raw material sources, chemicals for production, and suitable technologies. Consequently, methanol/methane production via biomass gasification or CO2 captured through conventional DAC process, followed by hydrogenation with renewable hydrogen, has been developed. After a joint evaluation, methanol emerged as the preferred option. Its production involves utilizing point sources of CO2 employing MEA solutions and renewable hydrogen supplied by PV panels together with wind turbines, with prices ranging between 1,000-2,600 €/tMethanol. Analyzing methane production, prices range from 18.97-20.36 €/MMBTU in 2022 and decrease to 8.90–9.09 €/MMBTU by 2050. With carbon taxes applied, prices are reduced to 2–3 €/MMBTU, competitive with market prices. Additionally, methane production from the gasification of lignocellulosic dry biomass, coupled with CO2 capture via MEA solutions, has been studied to ensure national energy security. The methane price range is 3.818-30.229 €/MMBTU from 2022 to 2050, with consideration of carbon taxes resulting in a price of 3.146 €/MMBTU.

2024-01-01T00:00:00Z