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The construction industry’s high demand for natural resources, combined with the waste generated by agriculture, creates an opportunity for the circular economy. This experiment used the CaCO3 found in scallop shells as an ingredient for the manufacture of fire-resistant materials, replacing gypsum in compositions of 40% and 50% by weight. The mechanical compressive strength was estimated for both freeze-thaw cycles and acid and sulfate attacks. The cost of disposing of scallop shell waste in landfills, savings from substitution, and the payback period relative to the amount of production were determined. The compressive strength of the materials decreased by 80% when subjected to freeze-thaw cycles and sulfate attack. In response to acid attack, they showed a 100% increase in strength during the first three weeks and a decrease thereafter. The savings amounted to $46.36 (22.4%) for 40% replacement and $58.93 (28.4%) for 50%. Respectively, return on investment is achieved at 800- and 630-per-metric ton produced. The difference between the costs of waste disposal (in aquaculture) and the potential savings from using CaCO3 as a raw material (in construction) creates an opportunity for commercialization between the two industries, serves as a reference for decision-makers, and complies with circular economy principles, reducing both inputs of raw materials and outputs of waste.

2 Figuras.-- 2 Tablas, The use of olive mill solid waste (OMSW) for energy production has mainly been promoted through combustion processes. However, the EU is promoting the substitution of combustion in favor of greener alternatives. Several publications have stated that the energy obtained from anaerobic digestion (AD) is a feasible waste‐to‐energy technology for OMSW. However, these studies lack reliable energy balances that can assess this statement. The present research work aims to address this issue by evaluating the energy potential of the biomethanization of OMSW in comparison with the current combustion technology, based on a review of the available scientific literature. The present analysis demonstrates that the AD of OMSW can generate a net energy production in the same range as that obtained from the OMSW combustion, qualifying AD as an alternative to combustion but not clearly offering a surplus of energy production. © 2020 Society of Industrial Chemistry and John Wiley & Sons Ltd, Funding Information Universidad de Sevilla. Grant Number: mobility grant PP2019‐532

A process to produce 1,3-butadiene (1,3-BD) from ethanol in a one-step reaction with a Hf–Zn catalyst was designed using experimental data from the catalyst performance under industrial conditions,...

There is a growing interest in the production of biobutadiene from bioethanol, but it is not possible to conclude from the literature which conversion process, either by one or two reaction steps, is preferred since there is a lack of works comparing their economic and environmental performances. The aim of this work is to perform that comparison so it can serve as a guide for decision making by future investors as well as set future research needs that can improve the technology. Assuming production in Brazil from sugarcane ethanol, technoeconomic and lifecycle assessments were performed from process simulations, and the reliability of the results was studied with uncertainty analyses. The comparison reveals that the one-step process should be preferred because of its better economic and environmental performance. Biobutadiene from ethanol is not cost competitive against naphtha-derived butadiene (probability of positive net present value is 11–17% for one-step process scenarios and 5% for the two-step process scenarios) but producing biobutadiene from ethanol in Brazil leads to significant reductions in emissions of CO2 compared to naphtha-derived butadiene (102–103% and 7.6–52.4% for one- and two-step process scenarios, respectively). A critical issue for the cost competitiveness of biobutadiene is that the CO2 saved can be sold in an international carbon emission trading market. In that case, the one-step processes would be much more favored. Future research is needed concerning the development of highly selective two-step catalysts operating in less energy-demanding conditions so that two-step processes can compete with one-step processes.

The production of strawberry concentrate produces a side stream after extrusion that is commonly landfilled. This strawberry extrudate (SE), of lignocellulosic character, contains valuable bioactive compounds such as sugars and phenols. Thermal treatments, such as steam explosion, are currently used for the valorisation of agricultural lignocellulosic wastes due to their ability to impact the structure of the lignocellulose and hemicellulose present in these wastes, favouring the disruption of fibrous material. Steam explosion has already been shown as a promising technology for phenol recovery from SE. Biogas is an additional valuable resource that might be produced from thermally pretreated and de-phenolised SE. This study assessed the influence of a steam-explosion pretreatment and the subsequent recovery of phenolic compounds from the long-term operation of a semi-continuous anaerobic digester of pretreated SE. The anaerobic digestion of SE steam exploded at 220 &deg, C for 5 min and de-phenolised was stable at an OLR of 0.5 g of volatile solids (VS)/(L&middot, d), which permitted a specific production rate of 135 &plusmn, 11 mL of CH4/(g of VS&middot, d). The system was not able to operate at an OLR of 1 g of VS/(L&middot, d), which resulted in a failure of the process. Despite the inhibition threshold of phenolic compounds not being achieved, the inhibition of the anaerobic digestion process at an OLR of 1 g of VS/(L&middot, d) was most likely due to the overloading of the system. This was indicated by the accumulation of soluble organic matter and volatile fatty acids. The increase in the propionic acid concentration up to 1300 mg/L when operating at OLRs higher than 0.5 g of VS/(L&middot, d) could be the main factor responsible for the inhibition. An economic evaluation showed that the proposed approach (steam explosion, phenol recovery, and anaerobic digestion) would offer positive benefits, taking into account the high phenolic recovery (0.90 g of gallic acid equivalents/kg of extrudate) and the low sales price of the phenol extract, i.e., EUR 0.610/g of gallic acid equivalents, needed to reach zero net profit.

The productive sector must incorporate waste into traditional materials in order to grow sustainably. In Galicia (Spain) alone, the canning industry produces over 150,000 metric tons of seashell waste per year. Most of this waste is still disposed of in landfills or open fields due to the lack of a technically feasible, environmentally sustainable, and economically profitable recycling alternative. This paper aims to study the feasibility of a new recycling alternative for seashell waste from industrial canning, based on the production of fireproof material suitable for construction use. The waste was pre-treated in order to remove salts and remaining organic matter and reduce particle size. According to international standards, physical, mechanical, and insulating properties were assessed for four compositions: 0, 40, 60 and 80% of gypsum substituted with pre-treated seashell waste. Results showed that substitution of up 60% gypsum was technically feasible. A Life-Cycle Assessment and a preliminary production cost analysis were performed by analysing a recycling case in Galicia. The case study found that 40–60% gypsum substitution obtained an environmental impact reduction of 0.4%–59% for 13 of the 18 impact categories considered compared with 0% substitution. Increases in the other 5 categories were analysed due to aquatic emissions released in the waste pre-treatment washing process. The locations of the fireproof material production facility and the waste source were a key factor. Production costs could be reduced by 20–31% by using 40–60% gypsum substituted with seashell wastes.

The concept of the “flexibility principle” introduced by the Integrated Pollution Prevention and Control Directive in the procedure to determine the emission limit values in the permit raised the interest of several scholars and heightened the debate on environmental regulation. The Integrated Pollution Prevention and Control Directive allows a considerable flexibility to competent authorities in the permitting process to deviate from the use of best available techniques described in the reference documents. Several studies show how this flexibility lead to disparities in the permitting process among Member States, which reduced the potential benefits in the environmental performance of companies. After the adoption of the Industrial Emissions Directive by the Member States of the European Union, the permit contents of around 52,000 of the largest European Union industrial installations need to be updated by competent authorities to meet the requirements of this Directive. Several studies on its effectiveness have been developed to determine how emission limit values are set by competent authorities with reference to the range of emission levels associated with the best available techniques. This paper is oriented to study the effect of the Industrial Emissions Directive at sector level, investigating its effects on the air emission limit values set by the competent authorities in the permits for cement facilities. This paper contributes to the scientific debate in relation to the effect of these Directives on the environmental performance of the industrial installations. The data analysed in the case study considered show that the emission limit values have been reduced in permits consistently over the past 10 years.

Digestate treatment techniques have recently been proposed as a strategy to increase the ultimate biogas yield from dairy manure and to improve the digestate quality as an organic fertilizer. These studies however rarely take the trace elements (TE) and nutrient partitioning into account. This study focusses on ozone treatment (5–40 g O3 kg−1 Total Solids (TS)) as a digestate treatment technique to control the concentration of TE and nutrients in the liquid phase of the digestate. Controlling the TE and nutrient concentrations in the liquid and solid digestate can improve the agronomic value of dairy manure digestate. The ozone concentration of the gas stream entering reactor was 48.53 g O3/Nm³ or 3.4% w/w O3 in O2-gas. The experiments were repeated using pure oxygen gas to investigate its influence. The results from ozonation and oxygenation of the dairy manure digestates revealed that O3 treatment up to 40 g O3 kg−1 TS did not have a more pronounced effect on the biochemical parameters compared to supplementation of pure O2. Ozonation of the digestate and the supernatant showed that the TE concentration in the liquid phase followed a parabolic profile. The observed initial increase in this parabolic profile was explained by the release of TE from the organic matter to the supernatant causing an increase in TE concentration, followed by a decrease due to precipitation of TE as hydroxides and sulfides, due to the increasing pH and sulphur concentrations. ispartof: Chemosphere vol:252 ispartof: location:England status: Published online

Waste recycling is an essential part of waste management. The concrete industry allows the use of large quantities of waste as a substitute for a conventional raw material without sacrificing the technical properties of the product. From a circular economy point of view, this is an excellent opportunity for waste recycling. Nevertheless, in some cases, the recycling process can be undesirable because it does not involve a net saving in resource consumption or other environmental impacts when compared to the conventional production process. In this study, the environmental performance of conventional absorption porous barriers, composed of 86 wt % of natural aggregates and 14 wt % cement, was compared with barriers composed of 80 wt % seashell waste and 20 wt % cement through an attributional cradle-to-grave life cycle assessment. The results show that, for the 11 environmental impact categories considered, the substitution of the natural aggregates with seashell waste involves higher environmental impacts, between 32% and 267%. These results are justified by the high contribution to these impacts of the seashell waste pre-treatment and the higher cement consumption. Therefore, the recycling of seashells in noise barrier manufacturing is not justified from an environmental standpoint with the current conditions. In this sense, it could be concluded that life cycle assessments should be carried out simultaneously with the technical development of the recycling process to ensure a sustainable solution. Gobierno Regional de Coquimbo (Chile) BIP 40014353-0

4 Tablas.-- 6 Figuras, The present study aims to use pH as a control parameter for the accumulation of target compounds. Solubilisation of wasted strawberry through fermentation at different operational pH (pH 4, 7, and 9) was evaluated. Methane as a target compound was achieved at pH 7, reaching a value up to 353 ± 10 mL CH4/g VS (VS, volatile solids). Operation at pH 9 was hardly controlled due to the low pH of the substrate and the accumulation of VFA. pH 9 resulted in the highest accumulation of VFA, mainly acetic acid. The operation at pH 4 resulted in the inhibition of the biogas production, leading to the concentration of soluble phenols up to 3 times the initial concentration in the reactors. The concentrations of pelargonidin 3-glucoside and p-coumaric acid showed a significant increase at pH 4 (p = 0.157 and p = 0.058, respectively). Acidogenic fermentation could be a suitable method to solubilise bioactive compounds from wasted strawberries without the necessity of high-energy pre-treatments. The low energy demand, i.e. 19 equivalent kJ/g gallic acid, as well as the high phenol solubilisation capacity, indicates that the acidogenic fermentation at pH 4 it is a promising method for the recovery of phenols from wasted strawberry., This research work was funded by the University of Queensland through to the project UQECR1945969. The authors are very grateful to the Spanish Ministry of Economy and Competitiveness through the project CTM2017-83870-R. B. Alonso-Fariñas acknowledges the support of the mobility grant PP2019-532, granted by the University of Seville. The authors are very grateful to the companies Luvaberry® and SunnyRidge® for supplying the substrates.

For sustainable growth, an economic model must tend toward a circular system, especially in the field of waste management. This work focuses on the valorization of spent fluid catalytic cracking catalyst from oil refineries, which generate 400,000 metric tons of spent catalyst per year worldwide, most of which is sent to landfills. A new alternative to landfilling is proposed for this waste, based on the combination of acid leaching for the recovery of lanthanum, a valuable rare earth, and the reuse of the leached solid residue as a cement substitute. A comparative life cycle assessment was made, including four environmental impact categories, i.e. global warming, fossil resource scarcity, mineral resource scarcity and water consumption, in order to quantify the potential environmental benefits of secondary lanthanum recovery from industrial waste with respect to primary lanthanum extraction from mineral resources. A maximum of 85.6% La recovery was achieved and 15 wt% of cement can be substituted with leached solid residue without changing the original cement classification. The waste management process presented in this paper promotes the sustainable management of the spent fluid catalytic cracking catalyst and contributes to the development of a new resource for a critical material such as lanthanum. The implementation of this novel waste management process could reduce global warming and mineral resource scarcity but would increase fossil resource scarcity and water consumption in comparison with primary La extraction.

© 2020 by the authors., Anaerobic digestion is a promising alternative to valorize agrifood wastes, which is gaining interest under an environmental sustainability overview. The present research aimed to compare anaerobic digestion with olive pomace oil extraction, by using life cycle assessment, as alternatives for the valorization of the olive mill solid waste generated in the centrifugation process with a two-outlet decanter from oil mills. In the case of olive pomace oil extraction, two cases were defined depending on the type of fuel used for drying the wet pomace before the extraction: natural gas or a fraction of the generated extracted pomace. The anaerobic digestion alternative consisted of the production of biogas from the olive mill solid waste, heat and electricity cogeneration by the combustion of the generated biogas, and composting of the anaerobic digestate. The life cycle assessment showed that anaerobic digestion was the best alternative, with a global environmental impact reduction of 88.1 and 85.9% respect to crude olive pomace oil extraction using natural gas and extracted pomace, respectively, as fuel., This research was funded by the Spanish Ministry of Economy and Competitiveness by Project CTM2014-55095-R.

Long-term human Space missions will rely on regenerative life support as resupply of water, oxygen and food comes with constraints. The International Space Station (ISS) relies on an evaporation/condensation system to recover 74–85% of the water in urine, yet suffers from repetitive scaling and biofouling while employing hazardous chemicals. In this study, an alternative non-sanitary five-stage treatment train for one “astronaut” was integrated through a sophisticated monitoring and control system. This so-called Water Treatment Unit Breadboard (WTUB) successfully treated urine (1.2-L-d−1) with crystallisation, COD-removal, ammonification, nitrification and electrodialysis, before it was mixed with shower water (3.4-L-d−1). Subsequently, ceramic nanofiltration and single-pass flat-sheet RO were used. A four-months proof-of-concept period yielded: (i) chemical water quality meeting the hygienic standards of the European Space Agency, (ii) a 87-±-5% permeate recovery with an estimated theoretical primary energy requirement of 0.2-kWhp-L−1, (iii) reduced scaling potential without anti-scalant addition and (iv) and a significant biological reduction in biofouling potential resulted in stable but biofouling-limited RO permeability of 0.5 L-m−2-h−1-bar−1. Estimated mass breakeven dates and a comparison with the ISS Water Recovery System for a hypothetical Mars transit mission show that WTUB is a promising biological membrane-based alternative to heat-based systems for manned Space missions.

This paper presents a comprehensive list of Carbon Capture and Utilization technologies and applications, ranging from lab-scale R&D activities reported in academic papers to commercially establish...

All building materials contain amounts of natural radioactive nuclides and heavy metals, but when waste materials are to be used in building materials, industrial processing can lead to further enhancement of the concentrations of nuclides and heavy metals in the waste. In this paper fly ashes were used as a raw material to replace natural clay to make fired bricks. The effects of a high replacement ratio (from 0% to 100%) of clay with fly ash on the mechanical, radiological and leaching properties of bricks were analyzed. A study of the different sintering temperatures of bricks was carried out at the selected temperatures of 800, 900 and 1000 °C. When the temperature was increased the mechanical strength was also increased. Two leaching tests (one batch and the other monolithic) were carried out and the bricks with a high replacing ratio did not present problems regarding the heavy metal leaching in either test. The contents of three radionuclides (220Ra, 232Th and 40K) were analyzed and the Activity Concentration Index of the bricks was calculated and was lower than 1, indicating a radiation exposure lower than 1 mSv y−1.

The reuse of two wastes from coal combustion in the manufacture of panels to be used as building materials or in the protection of metal structures against fire was analysed in this study. The panels were composed of 100% coal combustion by-products. The wastes used were fly ashes and flue gas desulfurisation gypsum from the combustion of coal in a Spanish power plant. The gypsum was previously calcined for 6 h at 150°C. Different mixtures of gypsum and fly ash were tested. The mixtures were kneaded with water until a homogeneous paste was achieved, with which moulds were filled. After 28 d at ambient temperature, the panels were subjected to different physical (density, pH and humidity), mechanical (compressive strength and surface hardness) and fire-resistance tests. Moreover, leaching tests were applied to the fly ash and gypsum. The results obtained were evaluated with the requirements established in some European standards for commercial gypsum products. The fire resistance of the panels under study was found to be higher than that of commercial gypsum and they also showed good mechanical properties.

Electrochemical water softening was proposed as a sustainable alternative for ion exchange softening, avoiding the input of salt to drinking water and the production of a concentrated brine. Here we demonstrated two novel modes of operation combining an electrochemical cell with a fluidized bed crystallizer. The first approach relied on an electrochemical cell consisting of an anode and cathode separated by a cation or anion exchange membrane. The feed water was first directed into a crystallizer where it was blended with alkaline cathode effluent. The effluent of the crystallizer, softened water, was in part recirculated to the cathode to generate alkalinity, in part to the anode compartment, where the pH was again decreased. Average removal efficiencies for calcium and magnesium of 75-86% and 7-21% respectively, could be sustainably reached, at a specific energy consumption of 7.0-10.1 kWh kg(-1) CaCO3 (0.86-1.39 kWh m(-3) water). This configuration allowed reagent-free water softening, albeit with an effluent with a pH between 3.0 and 3.6. In a second mode of operation, the process influent to soften was also directed to the crystallizer and recirculated over the cathode, which was separated from the anode using an anion exchange membrane. In this mode of operation, the cathode effluent was sent through the crystallizing unit, and the anode compartment was operated in closed-loop. Average calcium and magnesium removal efficiencies of 73-78% and 40-44% were obtained at specific energy consumptions of 5.8-7.5 kWh kg(-1) CaCO3 (0.77-0.88 kWh m(-3) water). Although the softened water had an elevated pH (similar to 9.4), the advantage of this configuration is concomitant removal of anions and the formation of acids/disinfectant in the anode compartment. Both methods of operation thus showed reagent-free water softening at a relatively low specific energy consumption. These novel methods of softening could be used in remote locations where access to chemicals or discharge of ion exchange brines proves to be difficult, or in case addition of chemicals for softening is unwanted. Further research is needed to further decrease the specific energy consumption during long-term operation. (C) 2019 Elsevier Ltd. All rights reserved.

Most of the aggregates in construction material come nowadays from the quarrying of natural resources, and their consumption tends to rise. The aim of this study was to evaluate the total s...

13 Páginas.-- 5 Tablas.-- 7 Figuras, Steam-explosion is a promising technology for recovering phenolic compounds from olive mill solid waste (OMSW) due to its high impact on the structure of the fibre. Moreover, the recovery of the phenols, which are well-known microbial inhibitors, could improve the subsequent biomethanization of the dephenolized OMSW to produce energy. However, there is a considerable lack of knowledge about how the remaining phenolic compounds could affect a long-term biomethanization process of steam-exploded OMSW. This work evaluated a semi-continuous mesophilic anaerobic digestion of dephenolized steam-exploited OMSW during a long operational period (275 days), assessing different organic loading rates (OLRs). The process was stable at an OLR of 1 gVS/(L·d), with a specific production rate of 163 ± 28 mL CH4/(gVS·d). However, the increment of the OLR up to 2 gVS/(L·d) resulted in total exhaust of the methane production. The increment in the propionic acid concentration up to 1486 mg/L could be the main responsible factor for the inhibition. Regardless of the OLR, the concentration of phenolic compounds was always lower than the inhibition limits. Therefore, steam-exploited OMSW could be a suitable substrate for anaerobic digestion at a suitable OLR, This research was funded by the [Spanish Ministry of Economy and Competitiveness] through Project grant number CTM2014-55095-R and the Ramon y Cajal Programme (RyC 2012-10456). Sergio López acknowledges the financial support from the ‘V Own Research Plan’ of the University of Seville (VPPI-US) for his research contract. This contracts is cofunded by the European Social Fund.

Coal is the world's most abundant fossil fuel source, is efficient, and less expensive than most other energy. Burning and gasification of coal, however, generate environmental problems. Clean coal technologies address this problem, which include a new generation of abatement techniques, some currently available and others being developed. These techniques have the ability to sharply reduce CO2 and pollutant emissions into the atmosphere. The most important pollutants to air from coal are nitrogen and sulfur oxides (NOx and SOx) and particulate matter. In this chapter, the basic characteristics and new trends of the most relevant pollutant control techniques applied to gas cleaning in coal combustion power plants and integrated gasification combined cycle are discussed in detail.

The aim of the present work was to evaluate the effects of a thermal pre-treatment of olive mill solid waste (OMSW) and phenol extraction process on the semi-continuous anaerobic digestion of this pre-treated waste during a prolonged operational period (275 days) in order to assess the organic loading rates (OLR) of 1 ad 2 g Volatile Solids (VS)/(L·d). The anaerobic digestion of thermally pre-treated and de-phenolized OMSW was stable at an OLR of 1 g VS/(L·d), which permitted a specific production rate of 172 ± 60 mL CH4/(g VS·d). However, the system was not able to operate at an OLR of 2 g VS/(L·d), which resulted in the total failure of the process. Regardless of the applied OLR, the phenolic compounds were effectively degraded and the inhibition thresholds were not reached. The inhibition of the anaerobic digestion process at an OLR of 2 g VS/(L·d) was probably due to the overloading of the system, indicated by the accumulation of organic matter and volatile fatty acids. The operation of the anaerobic digester under stable conditions allowed for high profitability for the proposed bio-refinery concept, which would still be profitable at a phenol extract price above 51.8 €/kg, which is 90% lower than the current price of 520 €/kg., The authors are grateful to the Spanish Ministry of Economy and Competitiveness for funding this research through Project CTM2014-55095-R and the Ramon y Cajal Programme (RyC 2012-10456).

This paper studies the feasibility of utilizing co-combustion fly ashes for the production of eco-friendly fired bricks. The fly ashes from co-combustion of coal and pet coke in a Spanish Power Plant were used as raw material to replace clay to make fired bricks. The effect of fly ash with high replacing ratio (from 0 to 80%) of clay on properties of bricks was analysed. The specimens, cylinders with 32.5 mm diameter and 50 mm length, were manufactured by compressing at 10 MPa. Different firing temperatures, 800, 900 and 1000 °C, were studied. The fired bricks with high volume ratio of fly ash present a high compressive strength and a low water absorption capacity. With increase in firing temperature, the compressive strength increased and the water absorption decreased. With increase in replacing ratio, the compressive strength decreased and the water absorption ratio increased. The bricks no present environmental problems according to the leaching study.

This paper presents an experimental analysis on a new board composed of gypsum and fly ashes from coal combustion, which are mutually compatible. Physical and mechanical properties, sound absorption coefficient, thermal properties and leaching test have been obtained. The mechanical properties showed similar values to other commercial products. As far as the acoustic insulation characteristics are concerned, sound absorption coefficients of 0.3 and 0.8 were found. The board presents a low thermal conductivity and a fire resistance higher than 50 min (for 4 cm of thickness). The leaching of trace elements was below the leaching limit values. These boards can be considered as suitable to be used in building applications as partitions.

This paper is aimed at performing an environmental evaluation regarding biofuel production. The process combines four sections: biomass fast pyrolysis to bio-oil with two phases, oil-phase upgrading by hydrotreating, using H2 obtained by steam reforming, and a new process to produce Fischer-Tropsch biofuels from supercritical water reforming of the aqueous phase. This phase can be valorised in the latter process entirely so natural gas is reformed to H2 (case-study 1), or partially so a fraction of this aqueous phase is reformed (case-study 2), or all this phase is reformed to H2 (case-study 3). The two former can include CO2 storage and aqueous phase concentrations were 15, 25 and 35 wt% organic compounds. At 25 wt%, the global warming potential is 11 g CO2-eq/MJ-biofuel for the case 2 with CO2 storage, while it was 11.3, 12.6, 27.7 and 34 g CO2-eq/MJ-biofuel for the cases 3, 2 without CO2 storage, 1 with and without CO2 storage, respectively. Thus, the case-study 2 with CO2 storage gives the minimum global warming potential, allowing significant reductions with respect to the use of fossil fuels. For the other categories, the case-study1 presents the lowest impacts. Similar trends are found at 15 and 35 wt%.

The use of biomass for production of chemicals is gaining interest because of its potential to contribute towards a reduction in greenhouse gas emissions and other environmental benefits linked to the substitution of fossil resources. But, conversely to biofuels, studies focusing on environmental impacts of biomass-derived chemicals are scarce. This paper uses life cycle assessment to evaluate the environmental sustainability of bio-ethylene from poplar produced by the following three thermo-chemical routes: direct and indirect dehydration of ethanol and production of olefins via dimethyl ether. The indirect route is the best option for most impact categories for all three allocation methods considered: system expansion, economic and energy basis. However, the dimethyl ether-to-olefins route has the lowest global warming potential. In comparison to ethylene produced bio-chemically from sugar beet, the thermo-chemical indirect route has lower impacts for all categories except human, terrestrial and freshwater toxicities. All three thermo-chemical alternatives show a significant reduction in global warming potential (up to 105% in the case of dimethyl ether-to-olefins) and depletion of fossil fuels when compared to conventional ethylene production from fossil fuels. However, the results also suggest that bioethylene produced by any of the three thermo-chemical routes would lead to a significant increase in most other impact categories relative to fossil fuels. Therefore, while trying to reduce greenhouse gas emissions, the overall environmental sustainability of bio-ethylene suffers from the increase in other environmental impacts. Universidad de Sevilla VPPI-US

Coal-fired power plants are considered to be one of the industrial technologies with a substantial contribution to climate change. In order to reduce their environmental impact, carbon capture and storage have acquired importance as a future clean coal technology in short and medium term. Concerning the closer-to-market options for CO2 capture, oxy-combustion is seen as one of the promising zero-emission plants due to the possibility of its suitability in existing boilers. This technology uses oxygen as the oxidant for combustion, providing a raw CO2 product which contains mainly water vapor, oxygen and nitrogen. Currently, cryogenic air separation is the only available mature option on a commercial scale. However, this system involves a high capital investment and an energy penalty in the oxy-fuel process, thus hindering its full-scale commercialization. As oxygen transport membranes offer significant advantages compared to the previous alternative, this option is foreseen as a candidate for its replacement. This work includes a review of this system and focuses on the study of the possible alternatives for integration into the oxy-fuel combustion process. As a result of this research, the compiled information has been homogenized, providing a completed base data related to operating parameters, required equipment and location of the combustion process for each studied alternative.

In a society where the environmental conscience is gaining attention, it is necessary to evaluate the potential valorization options for agricultural biomass to create a change in the perception of the waste agricultural biomass from waste to resource. In that sense, the biorefinery approach has been proposed as the roadway to increase profit of the agricultural sector and, at the same time, ensure environmental sustainability. The biorefinery approach integrates biomass conversion processes to produce fuels, power, and chemicals from biomass. The present review is focused on the extraction of value-added compounds, anaerobic digestion, and composting of agricultural waste as the biorefinery approach. This biorefinery approach is, nevertheless, seen as a less innovative configuration compared to other biorefinery configurations, such as bioethanol production or white biotechnology. However, any of these processes has been widely proposed as a single operation unit for agricultural waste valorization, and a thoughtful review on possible single or joint application has not been available in the literature up to now. The aim is to review the previous and current literature about the potential valorization of agricultural waste biomass, focusing on valuable compound extraction, anaerobic digestion, and composting of agricultural waste, whether they are not, partially, or fully integrated., The authors are very grateful to the Spanish Ministry of Economy and Competitiveness for funding this research through the Projects CTM2017-83870-R and AGL2016-79088R, with this project co-funded by an European Social Fund (ESF), and the Ministry of Economy and Competitiveness Ramon y Cajal Programme (RyC 2012-10456).

Flue gas conditioning (FGC) systems are an effective option for improving the performance of electrostatic precipitators (ESP). The effect of FGC on the cohesive forces in ash layers during electrostatic precipitation has been studied for a complete range of ash compositions. Cohesive forces have been determined by means of a laboratory apparatus specifically developed within this research work. SO3 and NH3 have been tested as conditioning agents. It is concluded that the effect of injecting NH3 on the cohesive properties is variable, and depends on the type of ash. The mechanism of NH3 adsorption, influenced by the carbon content in ash, appears to play an important role. On the other hand, SO3 addition involves the reduction of the cohesive forces in all the cases tested. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1379–1383, 2015

32 Páginas; 6 Tablas; 4 Figuras, A promising source of high added value compounds is the Olive Mill Solid Waste (OMSW). The aim of this research was to evaluate the viability of a biorefinery approach to valorize OMSW through the combination of steam explosion, phenols extraction, and anaerobic digestion. Steam explosion treatment increased the total phenol content in the steam exploited OMSW, which was twice than that the total phenol content in raw OMSW, although some undesirable compounds were also formed. Phenol extraction allowed the recovery of 2098 mg hydroxytyrosol per kg of OMSW. Anaerobic digestion allowed the partial stabilization of the different substrates, although it was not improved by the steam explosion treatment. The economic suitability of the proposed biorefinery approach is favorable up to a phenol extract price 90.7% lower than the referenced actual price of 520 €/kg., The authors are very grateful to the Spanish Ministry of Economy and Competitiveness for funding this research through Project CTM2014-55095-R. The authors also wish to express their gratitude to Ainoa Botana Samper for her assistance to this research.

35 Páginas; 6 Tablas; 3 Figuras, Circular bioeconomy has become a major issue for sustainable development in recent years. In the agricultural sector, circular economy focuses on the valorization and the pollution footprint reduction of organic waste. Due to the high volume generated and its high polluting potential, it is necessary to develop an economical and environmentally-friendly sustainable treatment of Olive Mill Solid Waste (OMSW). In the present study, a high-temperature thermal pre-treatment carried out at 170 °C for 60 min and a subsequent phenol extraction were proposed for OMSW valorization. A further anaerobic digestion step was proposed for the stabilization and energy recovery of pre-treated OMSW, with the necessity to study the effect of the inhibitory metabolites generated during the thermal pre-treatment in order to assess the viability of the process. Thermal pre-treatment induced organic matter solubilization and phenol generation with respect to untreated OMSW, with increases of 26.3% and 60.4%, respectively. Phenol extraction allowed the recovery of 1600 mg of hydroxytyrosol per 1 kg of OMSW. Thermal pre-treatment resulted in an improvement in the liquid fraction of both methane yield and methane production rate compared to untreated OMSW up to 16.9% and 6.9%, respectively. Further extraction of phenols produced a more significant enhancement of both methane yield and methane production rate in the de-phenolized liquid fraction compared to untreated OMSW, reaching improvements of 44.1% and 103%, respectively. The proposed economic assessment showed that the combination of high temperature thermal pre-treatment, phenol recovery and the subsequent biomethanization of the substrates was the most attractive treatment option. The economical suitability of the proposed biorefinery concept is favorable for a phenol extract price higher than 67.0 €/kg, 87% lower than the referenced actual price of 520 €/kg., The authors are very grateful to the Spanish Ministry of Economy and Competitiveness for funding this research through Project CTM2014-55095-R.

61 Páginas; 3 Tablas; 4 Figuras, The search for new materials that replace fossil fuel-based plastics has been focused on biopolymers with similar physicochemical properties to fossil fuel-based plastics, such as Polyhydroxyalkanoates (PHA). The present paper reviews the challenges of scaling-up PHA production from waste streams during the period from 2014 to 2016, focusing on the feasibility of the alternatives and the most promising alternatives to its scaling-up. The reviewed research studies mainly focus on reducing costs or obtaining more valuable polymers. In the future, the integration of PHA production into processes such as wastewater treatment plants, hydrogen production or biodiesel factories could enhance its implementation at industrial scale.

The development of robust and cost-effective hot gas filtration technologies is crucial to facilitate the implementation of advanced coal-based power systems. Understanding the structural characteristics of the dust cake, such as porosity, in relation to the pressure drop evolution is a subject of interest to improve the filtration process. This paper focuses on the study of dust cake compaction and its influence on cake porosity. A semi-empirical model based on Kozeny–Carman equation has been applied to experimental data from the operation of four types of commercial filters (two bag filters and two rigid filters) in a hot gas filtration experimental facility. The method proposed calculates the cake porosity from the specific dust cake resistance coefficient and dust properties. Cake porosity values obtained have been analysed to determine the effect of the operating parameters (filtration velocity, temperature and filtering media). Results show that filtration velocity is the variable that most affects the dust cake porosity. In addition, a correlation between filtration velocity and dust cake porosity has been established.

This article describes a number of tests that have been carried out using a pilot electrostatic precipitator (ESP) which operates with flue gases from a coal power plant. The purpose of these tests was to show the influence of the characteristics of the ash (resistivity) and the main design variables of an ESP (type of discharge electrode and collecting plate spacing) on the fouling of plates and discharge electrodes and the reentrainment of dust. Two types of coal, with high and low resistivity ashes, respectively, three types of discharge electrodes, and three typical collecting plate spacings were used in the tests. In fouling tests, the dust emission growth rate during periods with no rapping, the maximum permissible rapping interval, and the recuperation rate of the dust emission level after rapping were characterized. The maximum permissible rapping interval was defined as the time in which no alteration is observed in the operational variables of the ESP. In rapping tests, the relative increase of the dust emission level due to reentrainment was also characterized. The results of these tests have made possible to identify, for each of the tested coals, the ESP configurations (plate spacing and type of electrode) less sensitive to the formation of a permanent layer of ash and to the particle reentrainment due to rapping. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 7–14, 2015

The improvement of gas cleaning technologies is crucial for the establishment of advanced clean power generation coal-based technologies such as Integrated Gasification Combined Cycle (IGCC) or Pressurised Fluidized Bed Combustion (PFBC) which need high performance of the syngas clean-up process. New materials and advanced operating strategies at higher temperatures that could give lower energy penalty are required to be developed. A large scale high temperature filtration pilot plant is available at the ETSI University of Seville. This pilot plant allows testing different filtering elements and pulse cleaning strategies using real coal ash under an extensive range of operating temperature and pressure. The aim of the research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. An experimental campaign was carried out to test a new type of silicon carbide candle. Some prototype candles were fabricated from pyrolysed wood and other materials as result of a novel environment friendly patented process (BioSiC®). This process provides good thermo-mechanical, chemical and structural stability in an extensive range of temperatures. Main parameters for the characterisation of the prototype were studied such as filtration velocity, permeability, porosity, pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter. Optimal operating conditions and pulse cleaning strategies were determined. Additionally, a model to predict the behaviour of the filtering elements under diverse operating conditions was developed. In general, the experimental results showed that the prototypes are suitable for industrial applications under the operating conditions, typical of those required for hot gas cleaning of coal combustion and gasification gases, as used in this study. However, the possible improvements in the performance of the elements were identified that should be carried out in the next experimental campaign. This paper describes the main characteristics of the new material developed as well as the major results and conclusions from the analysis.

A semi-industrial filtration facility is currently in operation at the ETSI-University of Seville, with financial support from the European Commission and the Spanish Ministry of the Environment. This pilot plant allows testing different elements and reverse-flow pulse cleaning strategies using real coal ash and under diverse operating conditions such as temperature and pressure. The aim of the on-going research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. The first experimental campaign carried out in the filtration facility commenced in 2005. Four types of elements were tested at maximum temperature and pressure of 235 °C and 7.5 barg respectively. This paper describes the main results obtained during the second phase of the experimental campaign, in which the temperature was increased up to 370–550 °C. Three types of elements (one type of bag filter and two types of candles) were tested. Main parameters investigated for the characterisation of the filtering elements performance were the pressure drop across the element, the cleaning pulse interval, the baseline pressure drop, the filtration efficiency and the durability of the elements. Dependences on the particle loading and temperature among others were also established. Results obtained and conclusions extracted provide a useful tool for the implementation of the filtration technologies at industrial scale.

A high temperature high pressure filtration facility is available at the ETSI-University of Seville, which allows testing different elements and cleaning reverse-flow pulse strategies using real coal ash under diverse operating conditions. The facility is capable of processing 850 Nm 3 /h gas flow rate at maximum temperature and pressure of 550 °C and 7.5 barg respectively. An extensive testing campaigns have been carried out with the aim of evaluating alternatives for hot gas filtration technologies and optimising the performance of commercial filtering elements. In this framework, this paper focuses on a semi-empirical model developed for predicting the rise of the pressure drop with time. The model is based on theoretical considerations and the application of the experimental data generated using four filtering elements (PTFE and 3MFB700 bag filters, DSN1020 and CS1150 rigid filters). Nonlinear regression has been used to estimate and validate the coefficient of the model (specific dust cake coefficient) with arbitraries relations between independent and dependent parameters, by using iterative estimation algorithms. This is a valuable tool to select the best filtration options and optimum cleaning strategies in high temperature applications. Investigations about the factors affecting the specific dust cake resistance coefficient (filtration velocity, temperature, filter medium) are also presented.

The scope of this investigation is to develop a material mainly composed (80% w/w) of ceramic wastes that can be applied in the manufacture of road traffic noise reducing devices. The characterization of the product has been carried out attending to its acoustic, physical and mechanical properties, by measuring the sound absorption coefficient at normal incidence, the open void ratio, density and compressive strength. Since the sound absorbing behavior of a porous material is related to the size of the pores and the thickness of the specimen tested, the influence of the particle grain size of the ceramic waste and the thickness of the samples tested on the properties of the final product has been analyzed. The results obtained have been compared to a porous concrete made of crushed granite aggregate as a reference commercial material traditionally used in similar applications. Compositions with coarse particles showed greater sound absorption properties than compositions made with finer particles, besides presenting better sound absorption behavior than the reference porous concrete. Therefore, a ceramic waste-based porous concrete can be potentially recycled in the highway noise barriers field. El objetivo de este trabajo es desarrollar un material absorbente acústico compuesto fundamentalmente por residuos cerámicos (80% p) que se pueda utilizar en la fabricación de dispositivos reductores de ruido de carretera. La caracterización del producto se ha llevado a cabo atendiendo a sus propiedades acústicas, físicas y mecánicas, determinando el coeficiente de absorción acústica a incidencia normal, porosidad abierta, densidad y resistencia a compresión. La absorción acústica de un material poroso está fuertemente determinada por el tamaño de poro y por la longitud dela probeta sometida a ensayo. De este modo, se ha analizado la influencia del tamaño de partícula del residuo cerámico y del espesor de las muestras estudiadas en las propiedades del producto final. Los resultados obtenidos se han comparado con los obtenidos para un hormigón poroso elaborado con árido grueso, que se ha tomado como producto de referencia tradicionalmente empleado en este tipo de aplicaciones. Las composiciones elaboradas con el residuo de mayor tamaño de partícula han mostrado mayor absorción acústica, incluso mayor que las del hormigón poroso comercial. Por tanto, un hormigón poroso elaborado con residuos cerámicos puede ser potencialmente empleado como material en la fabricación de barreras acústicas de carretera.

A complete experimental campaign has been carried out in a hot gas filtration test facility so as to test different types of bag filters. The facility is designed to operate under a wide range of conditions, thus providing an excellent tool for the investigation of hot gas filtration applications for the conventional and advanced electrical power generation industry such as IGCC, PFBC or fuel cell technologies.