• Energy Research

Ceramic filter candles, partially filled with pellets of a commercial nickel-based catalyst (about 600 g) for hydrocarbons reforming, were recently tested for in-situ syngas cleaning and conditioning in the freeboard of a fluidized-bed biomass steam gasifier, with positive results (Savuto et al. 2019). To get full insight into the performance of that device, characterizing more accurately the dependence of catalytic activity on the operating conditions, a more focused approach is needed; this work describes an experimental study utilizing a laboratory-scale tubular reactor containing a small packed bed with pellets of the same catalyst (3.9 g), and involving steam reforming tests of tar key-compounds (mixtures of naphthalene and toluene, optionally with the addition of thiophene, vaporized in an inert gas stream together with steam). The experimental data were used to infer a lumped kinetic law, referred to the steam reforming of a pseudo-component representing tars. This law was implemented in a mathematical model of the annular catalytic packed bed inside the filtering candle, obtaining numerical simulations in fair agreement with gasification experiments from Savuto et al. 2019, as far as tar removal from biomass product syngas was concerned. Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 570-576

The environmental impact of traditional fuels and related greenhouse gas emissions (GHGE) has promoted policies driven towards renewable fuels. This review deals with green diesel, a biofuel obtained by catalytic deoxygenation of edible and non-edible biomasses. Green diesel, biodiesel, and petrodiesel are compared, with green diesel being the best option in terms of physical–chemical properties and reduction in GHGE. The deoxygenation process and the related types of catalysts, feedstocks, and operating conditions are presented. Reactor configurations are also discussed, summarizing the experimental studies. Several process simulations and environmental economic analyses—up to larger scales—are gathered from the literature that analyze the potential of green diesel as a substitute for petrodiesel. In addition, current industrial processes for green diesel production are introduced. Future research and development efforts should concern catalysts and the use of waste biomasses as feedstock, as well as the arrangement of national and international policies.

Abstract Continuous steam gasification of biomass is carried out in a fluidized bed reactor with the utilization of 10 wt%Fe/olivine catalyst. The volume composition of the product gas is analyzed by means of IR, UV and TCD for online detection of CO, CO 2 , CH 4 , H 2 , NH 3 and H 2 S. The results obtained have been evaluated with reference to a blank test (olivine bed inventory) performed with the same experimental rig: when 10 wt%Fe/olivine is utilized in the gasifier, the gas yield increases on average by 40% and the hydrogen yield by 88%. Correspondingly, the methane content in the syngas is reduced by 16% and tar production per kg of dry ash free (daf) biomass by 46%. 10 wt%Fe/olivine characterization after test shows that the catalyst is fairly stable.

The chemical looping gasification of residual biomasses—operated in fluidized beds composed of oxygen-carriers—may allow the production of biofuels from syngas. This biomass-to-fuel chain can contribute to mitigate climate change, avoiding the accumulation of greenhouse gases in our atmosphere. The ongoing European research project Horizon2020 CLARA (G.A. 817841) investigates wheat-straw-pellets (WSP) and raw-pine-forest-residue (RPR) pellets as feedstocks for chemical looping gasification. This work presents experimental results from devolatilizations of WSP and RPR, in bubbling beds made of three different oxygen-carriers or sand (inert reference), at 700, 800, 900 °C. Devolatilization is a key step of gasification, influencing syngas quality and quantity. Tests were performed at laboratory-scale, by a quartz reactor (fluidizing agent: N2). For each pellet, collected data allowed the quantification of released gases (H2, CO, CO2, CH4, hydrocarbons) and mass balances, to obtain gas yield (ηav), carbon conversion (χavC), H2/CO ratio (λav) and syngas composition. A simplified single-first order-reaction model was adopted to kinetically analyze experimental data. WSP performed as RPR; this is a good indication, considering that RPR is similar to commercial pellets. Temperature is the dominating parameter: at 900 °C, the highest quality and quantity of syngas was obtained (WSP: ηav = 0.035–0.042 molgas gbiomass−1, χavC = 73–83%, λav = 0.8–1.0); RPR: ηav = 0.036–0.041 molgas gbiomass−1, χavC = 67–71%, λav = 0.9–1.0), and oxygen-carries generally performed better than sand. The kinetic analysis suggested that the oxygen-carrier ilmenite ensured the fastest conversion of C and H atoms into gases, at tested conditions.

The reduction of CO2 emissions and solid waste disposal are critical issues with high importance for the environmental protection. Gasification is a promising process for sustainable energy production, because it can produce a versatile gaseous fuel starting from a wide range of organic feedstocks, and with reduced greenhouse gas emissions compared to combustion. Lignite is an abundant carbonaceous resource in Europe and in this work, gasification tests were carried out with lignite and a lignite and Solid Recovered Fuel (SRF) mixture, to evaluate the quality of gas produced from co-gasification of waste materials, in view of the final uses of the gas. Experimental gasification tests were carried out in a bench scale fluidized bed gasifier at different operating temperatures; the results were evaluated in terms of gas composition, tar content and conversion rates. In addition, characterization analyses were carried out on materials before and after the tests, and pressure fluctuation signals were analysed in order to evaluate the fluidization quality of the bed inventory.

Results are reported for the continuous steam gasification of biomass in a fluidized-bed reactor equipped with a catalytic ceramic candle filter in the freeboard. The filter, a silicon carbide base...

This work aims to study the selective catalytic hydrogenation of vegetable oils to maximize oleic acid content and expand the range of non-edible uses. Oleic acid (C18:1) is suitable for use as a biodegradable lubricant and is a building block in producing polymers and plastics from renewable resources. The challenge is the synthesis of heterogeneous catalysts, allowing for a maximum yield of C18:1 and low formation of the corresponding saturated acid (stearic acid). New copper-based catalysts on silica were synthesized via two synthesis methods: hydrolysis precipitation and ammonia-evaporation. Experimental tests were carried out at a lab scale operating in a semi-batch mode. The best conversion reached 90% for C18:3 and 80% for C18:2 HP Cu-silica catalyst results, the best candidate for an industrial case study. Good results were obtained in the selectivities of oleic acid production and cis/trans isomers ratio. The modified return on the investment of the designed hydrogenation plant provides the revenues of the capital costs in less than one year.