Towards circular economy solutions for the management of rice processing residues to bioenergy via gasification

An economic assessment of two circular economy scenarios of fluidized bed gasification-based systems for combined heat and power (CHP) generation, fueled with rice processing wastes, was conducted. In the first scenario, the gasification plant with a capacity of 42,700 t/y of rice husks provides a waste management solution for 5 small rice processing companies, located at the same are, while in the second scenario the gasification unit of 18,300 t/y capacity provides a waste management solution to only one rice processing plant, being a custom-made solution. The first scenario is the most economically viable, with an annual revenue of 168 €/(t*y), very good payout time (POT=1.05) and return in investment (ROI=0.72). The economic assessment was based on experiments performed at a laboratory-scale gasification rig, while the economic analysis was based on the SMARt-CHP technology, developed at Aristotle University, Greece. The experimental proof of concept of rice husks waste gasification was studied at a temperature range 700-900oC, under an under-stoichiometric ratio of O2/N¬¬2 (10/90 v/v), as gasification agent. Producer gas’s LHV maximized at 800oC (10.9 MJ/Nm3), while the char’s BET surface reached a max of 146 m2/g at 900oC. Recommendations were also provided for a potential pretreatment of rice husks in order to minimize de-fluidization problems of the gasification system

Investigation study for technological application of alternative methods for the energy exploitation of biomass/agricultural residues in Northern Greece

Biomass energy potential is addressed to be the most promising among the renewable energy sources, due to its spread and availability worldwide. Apart form that, biomass has the unique advantage among the rest of renewable energy sources, to be able to provide solid, liquid, and gaseous fuels that can be stored, transported, and utilized, far a way from the point of origin. For the northern region of Macedonia in Greece, biomass utilization is considered to be a major issue, due to the considerably intensive regional agricultural activities. Wood by-products, fruit cores, rice husk and cotton gin waste provide a promising energy source for the region. The energy potential of the available agricultural biomass produced in the region is much enough to cover the 10% of the annual oil consumption utilized for thermal applications. However, the cost of energy utilization of biomass is considerably high due to the high cost of the logistics concerning the collection, transport, and storage of biomass. The available utilization technologies developed, to handle efficiently all different species of biomass, cover a wide technological range. One of the most promising technologies involving thermal treatment of biomass and the production of a gaseous fuel (biogas) for industrial heat applications and electricity production, is the thermochemical conversion. In the present work, an investigation concerning biomass potential for energy production in the region of central Macedonia in Greece, utilizing several locally produced biomass species, is conducted. Emphasis is put on the energy utilization of agricultural by-products and residues. Agricultural sector is of greal importance due to the considerably intensive agricultural activities in the region of Central Macedonia

Probing synergies between lignin-rich and cellulose compounds for gasification

The fixed bed gasification of lignin rich and deficient mixtures was carried out to probe the synergistic effects between two model compounds, Lignin Pink (LP) rich in Na and Cellulose Microcrystalline (CM). Reaction conditions utilized the most commonly used air ratios in current wood gasifiers at 750 °C and 850 °C. It was found that by increasing the lignin content in the mixture, there was a selectivity change from solid to gas products, contrary to a similar study previously carried out for pyrolysis. This change in product mix was promoted by the catalytic effect of Na edge recession deposits on the surface of the char. As a result, the water gas shift reaction was enhanced at 850 °C for the LP48CM52 mixture across all air ratios, this was evidenced by a strong correlation between the produced H2 and COx. Meanwhile, by lowering the lignin content in the mixtures, the reactivity of cellulose microcrystalline was found to generate more char at higher temperature, similar to lignin mixtures when undergoing pyrolysis

Targeting sustainable bioeconomy: A new development strategy for Southern European countries. The Manifesto of the European Mezzogiorno

ABSTRACT: This policy-oriented opinion paper, which has taken the form of a Manifesto, is co-authored by scientists and engineers from Southern European Union countries that are presently experiencing deep and complex systemic crises: Portugal, Spain, Italy, Greece and Cyprus. With their Manifesto, the authors advocate the adoption of a new development model, focusing on the target of sustainable bioeconomy, around which other development themes and topics will crystallize. Implementing this model will act as a locomotive to get the economies and societies of these countries efficiently out of their crises, and smoothly into greener post-crisis pastures. The proposal is articulated in ten critical steps or theses for immediate action by the policy- and decision-makers, as well as industry, markets and other key actors within this troubled area of the European Mezzogiorno. Corroborating evidence of these theses comes in the form of short reports or "letters" on the key topics of this Manifesto from the countries and regions concerned.info:eu-repo/semantics/publishedVersio

Agricultural and forest biomass for food, materials and energy: bio-economy as the cornerstone to cleaner production and more sustainable consumption patterns for accelerating the transition towards equitable, sustainable, post fossil-carbon societies

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Products from the high temperature pyrolysis of RDF at slow and rapid heating rates

The high-temperature pyrolysis behaviour of a sample of refuse derived fuel (RDF) as a model of municipal solid waste (MSW) was investigated in a horizontal tubular reactor between 700 and 900 °C, at varying heating rates, and at an extended vapour residence time. Experiments were designed to evaluate the influence of process conditions on gas yields as well as gas and oil compositions. Pyrolysis of RDF at 800 °C and at rapid heating rate resulted in the gas yield with the highest CV of 24.8 MJ m-3 while pyrolysis to 900 °C at the rapid heating rate generated the highest gas yield but with a lower CV of 21.3 MJ m-3. A comparison of the effect of heating rates on oil products revealed that the oil from slow pyrolysis, contained higher yields of more oxygenates, alkanes (C8-C39) and alkenes (C8-C20), while the oil from rapid pyrolysis contained more aromatics, possibly due to the promotion of Diels-Alder-type reactions

Comparative Studies of the Pyrolytic and Kinetic Characteristics of Maize Straw and the Seaweed Ulva pertusa

Seaweed has attracted considerable attention as a potential biofuel feedstock. The pyrolytic and kinetic characteristics of maize straw and the seaweed Ulva pertusa were studied and compared using heating rates of 10, 30 and 50°C min−1 under an inert atmosphere. The activation energy, and pre-exponential factors were calculated by the Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Popescu methods. The kinetic mechanism was deduced by the Popescu method. The results indicate that there are three stages to the pyrolysis; dehydration, primary devolatilization and residual decomposition. There were significant differences in average activation energy, thermal stability, final residuals and reaction rates between the two materials. The primary devolatilization stage of U. pertusa can be described by the Avramic-Erofeev equation (n = 3), whereas that of maize straw can be described by the Mampel Power Law (n = 2). The average activation energy of maize straw and U. pertusa were 153.0 and 148.7 KJ mol−1, respectively. The pyrolysis process of U.pertusa would be easier than maize straw. And co-firing of the two biomass may be require less external heat input and improve process stability. There were minor kinetic compensation effects between the pre-exponential factors and the activation energy

Evaluation of the optimal activation parameters for almond shell bio-char production for capacitive deionization

A study on a possible new biomass waste to be used as electrode material for capacitive deionization (CDI) processes was performed. Raw almond shells were pyrolyzed at 800, 900 and 1000 °C and then activated through CO2. Carbon activation is used to develop porosity inside the material, increasing the specific surface area and the adsorption performances. In this work, authors tried to correlate the effects of pyrolysis and activation temperature on the ion storage capacity. Results from the desalination tests indicated that the best performance in terms of ion adsorption was obtained when the bio-char was activated at the temperature of 900 °C. Brunauer-Emmet-Teller (BET) and Barret-Joyner-Halenda (BHJ) analysis confirmed the trend of the CDI tests, reporting the highest surface area and share of micropore sites for the 900 °C samples. Salt adsorption capacity was found to be in the range of 13.7 to 19.2 mg g−1

Cynara cardunculus L. gasification in a bubbling fluidized bed: the effect of magnesite and olivine on product gas, tar and gasification performance

peer-reviewedGasification of Cynara cardunculus L. was performed in a bubbling fluidized bed (BFB) using air as gasifying agent and, magnesite and olivine as different bed materials. Temperature was varied during the experiments (700-800 degrees C) with fixed biomass feeding and air flow rate. The effect of using the magnesite and olivine on gas and tar composition, carbon and biomass conversion, and cold gas efficiency was investigated. The product gas showed high hydrogen content (13-16% v/v) for both magnesite and olivine in the studied temperature range. Higher heating value and gas yield were improved with increasing the temperature from 700 to 800 degrees C. Biomass and carbon conversion were greater than 75%, obtaining values higher than 90% for both 700 and 800 degrees C in magnesite and for 800 degrees C in olivine. Small differences in total tar were observed between materials, although tar composition was very different. BTEX were higher for olivine and similar PAHs was obtained for both magnesite and olivine. A higher catalytic activity at 800 degrees C was observed for magnesite. Gasification performance was better with magnesite at 700 degrees C while olivine showed better properties at 800 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.ACCEPTEDpeer-reviewe