Thermal gasification of agro-industrial wastes

sobre o potencial energético de resíduos agroindustriais da região de Portalegre. Os ensaios foram realizados utilizando uma unidade piloto de gaseificação térmica de biomassa, de leito fluidizado borbulhante, às temperaturas de 750◦ C, 800◦ C e 850◦ C, com caudais mássicos de 30 kg/h, 40 kg/h e 60 kg/h. Os resultados do estudo demonstram a influência negativa que o aumento da temperatura provoca no poder calorífico do gás de síntese. Os ensaios realizados a temperaturas inferiores, 750◦ C, revelam um aumento na concentração de CO entre os 10%-20%, e um decréscimo da concentração de N2 na ordem dos 10%, bem como de CO2 na ordem dos 5%, relativamente aos ensaios à temperatura de 850◦ C. Os resultados obtidos demonstram também que o aumento do caudal mássico é responsável pelo aumento do poder calorífico do gás de síntese para a biomassa cascarilha de café, nomeadamente, no aumento da concentração de CO, superior a 10% comparando os caudais de 30% e 60%, e o aumento da concentração de H2, que em alguns dos ensaios realizados chega quase a 50%. Para as biomassas miscanthus e caroço de pêssego o aumento de caudal foi prejudicial para o poder calorífico do gás de síntese. No entanto, o aumento da temperatura é favorável a uma diminuição da produção de alcatrões, no processo de gaseificação térmica. O estudo demonstra a viabilidade e potencialidade da utilização destas biomassas, com poderes caloríficos na ordem dos 4 MJ/kg a 6 MJ/kg, para a valorização energética através de gaseificação térmica

Energy recovery via thermal gasification from waste insulation electrical cables (Wiec)

project 0330_IDERCEXA_4_E project number 88881.156267/2017-01The recovery of noble metals from electrical wires and cables results in waste materials such as polyvinyl chloride (PVC) and polyethylene (PE), that is, waste insulation electrical cables (WIEC), which have been processed by gasification for energy recovery. This study focused on the effect of blending the ratio of WIEC on the gasification feedstock composition and the lower heating value (LHV) of produced syngas, through controlled tests and tests under different loads on the generator. The controlled gasification experiments were carried out at blending ratios between pine biomass and WIEC of 90:10, 80:20, and 70:30 and with pine biomass only (100%). For the loads gasification, the experiments were carried out at a blending ratio of 80:20. The controlled experimental results presented that the highest hydrogen content, approximated 17.7 vol.%, was observed at a blending ratio of 70:30 between pine biomass and WIEC and the highest LHV of syngas was observed at a blending ratio of 90:10, with 5.7 MJ/Nm3. For the load gasification experiments, the results showed that the highest hydrogen content was obtained with a load of 15 kW in the generator, approximately 18.48 vol.% of hydrogen content, and the highest LHV of synthesis gas was observed during the 5 kW test, with 5.22 MJ/Nm3. Overall, the new processing of waste insulation electrical cables using a downdraft gasification reactor demonstrates great promise for high quality syngas production.publishersversionpublishe

Pre-Feasibility Study of a Multi-Product Biorefinery for the Production of Essential Oils and Biomethane

Rural areas can benefit from the development of biorefineries for the valorization of endogenous feedstocks. In this study, a pre-feasibility assessment of an integrated multi-product biorefinery to produce essential oils and biomethane is carried out considering current technical and economic conditions. The proposed concept is based on the steam distillation of forestry biomass for the extraction of essential oils (2900 L/y) followed by biomethane production via syngas methanation using the spent biomass as feedstock (30.4 kg/h). In parallel, the anaerobic treatment of WWTP sludge (5.3 kg/h) is used to produce additional biomethane for mobile applications. The results show that the intended multi-product biorefinery delivers attractive benefits for investors as described by the calculated financial indicators: NPV of EUR 4342.6, IRR of 18.1%, and PB of 6 years. Overall, the pre-feasibility analysis performed in this study demonstrates that the proposed biorefinery concept is promising and warrants further investment consideration via cost and benefit analysis, ultimately promoting the implementation of multi-product biorefineries across Europe

Properties and Uses of Biochars Incorporated into Mortars

Funding Information: The authors would like to acknowledge financial support from the PigWasteBioRefinery Project—Pig biorefinery based on biological, thermal, and electrochemical processes—Demonstrator mobile pilot project, code ALT20-03-0246-FEDER-000054, and co-financed by the European Regional Development Fund (ERDF), through the Regional Operational Program of the Alentejo (ALENTEJO 2020). Publisher Copyright: © 2023 by the authors.The construction industry is responsible for a large amount of CO2 emissions and an intensive energy consumption. Cement production is the third largest source of anthropogenic CO2 emissions and is responsible for about 1.8 Gt of CO2 emissions into the atmosphere. The use of waste materials to replace a fraction of cement in the mortar makes it more economically and ecologically friendly. In this work, the main objective was to test incorporations of biochar produced at temperatures of 300, 350, and 400 °C, as a partial replacement for cement in the production of mortar. The materials used for the tests were residual lignocellulosic biomass (WBL) and electrical cable insulation waste (WIEC) mixed in a ratio of 1:1. The biochars produced were crushed and sieved after production to reduce the particles. A sample of biochar was used and tested under these conditions and another sample was washed in water and dried before being incorporated; all tests were carried out with a 5% replacement. Waste recovery tests were also carried out without thermochemical treatment. The specimens were studied for compressive strength and water absorption by immersion. All tests were replicated and were analyzed and compared with a control mixture with no incorporation of biochar in the mixture. It was possible to observe that the tests with the incorporation of biochars at 400 °C showed better results, with only a 24% reduction in resistance to compression.publishersversionpublishe

Techno-Economic Evaluation of Downdraft Fixed Bed Gasification of Almond Shell and Husk as a Process Step in Energy Production for Decentralized Solutions Applied in Biorefinery Systems

The objective of the present study was to carry out a technical study of the gasification of almond shells and husks at different temperatures and, subsequently, an economic analysis for the in situ installation of a decentralized unit to produce electricity, through a syngas generator, that would overcome the use of fossil fuels used in this agroindustry. The gasification tests were carried out at three different temperatures (700, 750 and 800 °C) and the results for the tests carried out were as follows: a 50:50 mixture of almond husks and shells was found to have a lower heating value of value of 6.4 MJ/Nm3, a flow rate of 187.3 Nm3/h, a syngas yield of 1.9 Nm3/kg, cold gas efficiency of 68.9% and carbon conversion efficiency of 70.2%. Based on all the assumptions, a 100 kg/h (100 kWh) installation was proposed, located near the raw material processing industries studied, for an economic analysis. The technical–economic analysis indicated that the project was economically viable, under current market conditions, with a calculated net present value of k€204.3, an internal rate of return of 20.84% and a payback period of 5.7 years. It was concluded that thermal gasification is a perfectly suitable technology for the recovery of raw materials of lignocellulosic origin, presenting very interesting data in terms of economic viability for the fixed bed gasification system

Production, Characterization, and Activation of Biochars from a Mixture of Waste Insulation Electric Cables (WIEC) and Waste Lignocellulosic Biomass (WLB)

Waste insulation electrical cables (WIEC) currently do not have an added value, due to their physical–chemical characteristics. Carbonization is known to enhance feedstock properties, particularly fuel and material properties; as such, this article aimed to study the production and activation of biochars using WIEC and lignocellulosic biomass wastes as feedstock. Biochars were produced in a ceramic kiln with an average capacity of 15 kg at different temperatures, namely 300, 350 and 400 °C. After production, the biochars were further submitted to a washing process with water heated to 95 °C ± 5 °C and to an activation process with 2 N KOH. All biochars (after production, washing and activation) were characterized regarding an elemental analysis, thermogravimetric analysis, heating value, chlorine removal, ash content, apparent density and surface area. The main results showed that the increase in carbonization temperature from 300 to 400 °C caused the produced biochars to present a lower amount of oxygen and volatile matter, increased heating value, greater chlorine removal and increased ash content. Furthermore, the activation process increased the surface area of biochars as the production temperature increased. Overall, the carbonization of WIEC mixed with lignocellulosic wastes showed potential in enhancing these waste physical and chemical properties, with prospects to yield added-value products that activates biochar