Thermodynamic and environmental assessment of different scenarios for the insertion of pyrolysis technology in palm oil biorefineries

The large quantities of residual biomass produced in the palm oil industry have become one of the mainenvironmental andfinancial concerns of this industry. For this reason, biorefineries are gaining strengthin recent years, since through their production model the residual biomass can be used as raw material toproduce bioenergetics (biofuels and bio-products), hence contributing to the reduction of greenhousegases emissions. Therefore, the main objective of this work is to compare and evaluate alternatives toconvert a conventional palm oil mill into a biorefinery considering energy and environmental sustain-ability indicators. In this context, this work presents a study of three scenarios: thefirst (I), the base case,consists of a traditional palm oil mill; the second (II) considers a palm oil mill working under the bio-refinery concept that uses the fast pyrolysis process for the production of bio-oil and biochar; and thethird (III) considers a biorefinery that, besides incorporating the pyrolysis process, has an extraction/transesterification stage for the production of biodiesel and glycerin in the palm oil mill. The surpluselectricity index was calculated for the three scenarios, and scenario III was the most favorable, achieving110.23 kW per ton of fresh fruit bunch with an overall efficiency of 82.69%. The environmental assess-ment carried out for scenario III indicates that environmental impacts of bio-oil production are 32.5%lower than the ones to produce electricity (climate change category) and 14.2% lower than environ-mental impacts to produce biodiesel (resources category), demonstrating that the production of bio-oilusing fast pyrolysis result in lower environmental impacts compared with the other products obtained inthe biorefinery. Finally, the Net Energy Ratio was calculated for the scenario with the best thermody-namic performance (scenario III: 21.17) and compared with previously published studies, resulting in again of total energyflow of up to 17.77.

Global potential assessment of available land for bioenergy projects in 2050 within food security limits

This paper evaluates the potential of available land area for bioenergy projects in 2050 without compromising food security. The paper’s novelty is the qualitative and quantitative assessment of parameters interfering with land availability for bioenergy projects. Unlike previous studies, the projections consider food waste, areas of degraded or abandoned land due to low productivity, and parameters generally overlooked by other authors, such as urban agriculture and insect protein consumption. Population’s food demand, agricultural productivity changes, and surplus land availability for biofuel production are bases for the methods employed. Three (3) different scenarios were defined: business as usual (Pessimistic Scenario - CP), the best of the realistic scenarios (Optimistic Conservative Scenario - CC), and the ideal situation (Ideal Scenario - CC). The authors did not consider social segmentation variations in land access, characterizing a weakness of the study. Projections disregard economic and market influences governing land use and distribution. Despite the risks to biodiversity because of agricultural frontiers’ expansion, there is enough arable land in the world to feed the population in 2050 in the three proposed scenarios. However, choosing to prioritize forest preservation and going for shrubland areas as the next agricultural frontiers, no arable land would remain in the Pessimistic Scenario for biofuels. Otherwise, agriculture would cause deforestation of 24% of forest area (935 million hectares) and causing massive envi-ronmental impacts. In the Optimistic Conservative Scenario, 5.7% of agricultural land would remain, supplying 92% of the 2100 target, and in the Ideal Scenario, 42.0% of agricultural land would remain, with the potential of reach the 2100 target more than 6 times. Bioenergy could contribute to 5–17.7% of the global energy matrix in the most realistic scenarios.

Assessment of the energy recovery potential of oil sludge throughgasification aiming electricity generation

Thermochemical conversion of oil sludge (OS) residues from crude oil refinery was studied as analternative for treatment and energy recovery before OSfinal disposal. A simulation model for OSgasification was developed and validated by using AspenPlus™V 11.0. Three scenarios by consideringdifferent gasifying agents were evaluated, aiming the assessment of different gasification parameters andperformance indexes such as gasification temperature, cold-gas efficiency, syngas yield, and LHV. Toevaluate the potential use of syngas to generate electricity, three different prime movers such as steamRankine cycle, gas microturbine, and gas-Internal Combustion Engine (ICE) were modeled. A hydrogen-rich syngas from OS gasification with air/steam mixture was reached (38.2 vol%) at ER 0.20. Syngas LHVand syngas yield ranged between 8.6 and 3.0 MJ/Nm3and 0.6e1.3 Nm3/kg OS, when ER was increasedfrom 0.25 to 0.45, respectively. The highest energy recovery potential (electricity generation) was ob-tained when using syngas to power a gas-ICE, with a generation index of about 0.47 kWh/kg-OS at ERratio of 0.25. Therefore, OS thermochemical conversion into syngas and its subsequent use to generateelectricity could be a technological alternative to oily residues management inside an oil refinery thatcould efficiently transform a dangerous residue into electricity.

Life Cycle Assessment (LCA) for use on renewablesourced hydrogen fuel cell buses vs diesel enginesbuses in the city of Rosario, Argentina

The purpose of this paper is to build the first Energy and Life Cycle Analysis (LCA) com-parison between buses with internal combustion engine currently used in the city ofRosario, Province of Santa Fe, Argentina, and some technological alternatives and theirvariants focusing on buses with an electrical engine powered by compressed hydrogen thatfeet fuel cells of polymer electrolyte membrane (PEM). This LCA comprehend raw materialextraction up to its consumption as fuel. Specifically, hydrogen production consideringdifferent production processes from renewable sources called“green hydrogen”(VelazquezAbad and Dodds, 2020) [1] and non-renewable sources called“grey hydrogen”(VelazquezAbad and Dodds, 2020) [1]. Renewable sources for hydrogen production are rapid cutdensified poplar energy plantation, post-industrial wood residues such as chips pallets,and maize silage. For non-renewable hydrogen production sources are the local electricalpower grid from water electrolysis and natural gas from the steam methane reformingprocess.Buses whose fuel would be renewable hydrogen, produced near the City of Rosario,Province of Santa Fe, Argentina, meet one of the main criteria of sustainability biofuels ofthe European Union (EU) taken into account Renewable Energy Directive (RED) 2009/28 and EU RED Directive 2018/2001 [3] that need significant reduction on net greenhouse gases(GHG) from biomass origin row material respect fossil fuels. At least 70% of GHG would beavoided from its main fossil counterpart of the intern combustion engine (ICE), in the worstand current scenario of the emission factor of the electrical grid of Argentina in the point ofuse that is about 0.40 kg CO2eq/kWh with energy and environmental load of 100% in theallocation factor in the hydrogen production stage of the LCA analysis.

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