Acid-Catalyzed Liquefaction of Biomasses from Poplar Clones for Short Rotation Coppice Cultivations

Liquefaction of biomass delivers a liquid bio-oil with relevant chemical and energetic applications. In this study we coupled it with short rotation coppice (SRC) intensively managed poplar cultivations aimed at biomass production while safeguarding environmental principles of soil quality and biodiversity. We carried out acid-catalyzed liquefaction, at 160 °C and atmospheric pressure, with eight poplar clones from SRC cultivations. The bio-oil yields were high, ranging between 70.7 and 81.5%. Average gains of bio-oil, by comparison of raw biomasses, in elementary carbon and hydrogen and high heating, were 25.6, 67, and 74%, respectively. Loss of oxygen and O/C ratios averaged 38 and 51%, respectively. Amounts of elementary carbon, oxygen, and hydrogen in bio-oil were 65, 26, and 8.7%, and HHV averaged 30.5 MJkg−1. Correlation analysis showed the interrelation between elementary carbon with HHV in bio-oil or with oxygen loss. Overall, from 55 correlations, 21 significant and high correlations among a set of 11 variables were found. Among the most relevant ones, the percentage of elementary carbon presented five significant correlations with the percentage of O (−0.980), percentage of C gain (0.902), percentage of O loss (0.973), HHV gain (0.917), and O/C loss (0.943). The amount of carbon is directly correlated with the amount of oxygen, conversely, the decrease in oxygen content increases the elementary carbon and hydrogen concentration, which leads to an improvement in HHV. HHV gain showed a strong positive dependence on the percentage of C (0.917) and percentage of C gain (0.943), while the elementary oxygen (−0.885) and its percentage of O loss (0.978) adversely affect the HHV gain. Consequently, the O/C loss (0.970) increases the HHV positively. van Krevelen’s analysis indicated that bio-oils are chemically compatible with liquid fossil fuels. FTIR-ATR evidenced the presence of derivatives of depolymerization of lignin and cellulose in raw biomasses in bio-oil. TGA/DTG confirmed the bio-oil burning aptitude by the high average 53% mass loss of volatiles associated with lowered peaking decomposition temperatures by 100 °C than raw biomasses. Overall, this research shows the potential of bio-oil from liquefaction of SRC biomasses for the contribution of renewable energy and chemical deliverables, and thereby, to a greener global economy.

New Technologies for Producing Multifunctional Reinforced Carbon Plastics

In this article we investigated properties of elementary carbon fibers after their activation and subsequent deposition of thin layers of metal coatings on their surface. For deposition we used copper, titanium and stainless steel. We investigated influence of various technologies of preliminary processing of the fiber surface on the value of the adhesion strength of the metal coating to the carbon tape and on the mechanical properties of elementary fibers. We established that the strength of carbon plastics at interlayer shear increases by 10-30% when using carbon tapes and fabrics with a metal coating.

Assessment of Co2 Emission by Tractor Engine at Varied Control Settings of Fuel Unit

The paper presents results of experimental studies concerning CO2 emission of S-4003 diesel engine Ursus C-360 at a variable fuel injection advance angle and opening pressure of injectors. Measurements were made on the dynamometric stand on the test bench. The engine operated according to the load characteristic at two characteristic rotational speeds i.e., at the maximum torque velocity (1600 rpm) and at the rated speed (2200 rpm). In each measurement point of load characteristics, CO2 concentration was measured in exhaust gases with the use of exhaust gases analyser M-488 Multigas Plus. For a more detailed analysis of the CO2 content in exhaust gases, additional change of O2 level emission was presented, which in the biggest amount combines elementary carbon included in fuel during combustion. The studies showed the CO2 content reduction in exhaust gases at the reduced (by 3º of crankshaft rotations) fuel injection advance angle in comparison to the nominal angle by 4.5% at the rotational speed of 1600 rpm and by 5.7% at the speed of 2200 rpm (the average values for all measurement points of load - brake horsepower of engine). Similarly, CO2 concentration decrease in exhaust gases of the investigated engine was reported for the increased (by 1.5 MPa) opening pressure of injectors in comparison to the nominal pressure, on average by 9.8% for the speed of the maximum rotational moment and by 4.5% for the rated speed.

Influence study of copper and zinc coatings on properties of carbon fibers and composites based on them

Two types of metallic coatings (copper and zinc) were deposited on the surface of a unidirectional carbon tape by the method of magnetron sputtering. Results of experimental evaluation of strength of elementary carbon fibers with these metallic coatings and carbon-reinforced plastics based on them are presented. It has been found that the copper coating increases strength of the fibers and the carbon-reinforced plastics in case of the interlaminar displacement. The zinc coating decreases strength of the fibers and composites based on them. Parameters of the carbon fibers with metallic coatings after long-term storage of metallized carbon tapes are presented.

Shipping emissions in the Iberian Peninsula and its impacts on air quality

Marine traffic has been identified as a relevant source of pollutants, which cause known negative effects on air quality. The Iberian Peninsula is a central point in the connection of shipping traffic between the Americas and Africa and the rest of Europe. To estimate the effects of shipping emissions inland and around the Iberian Peninsula, EMEP MSC-W model was run considering and not considering shipping emissions (obtained with STEAM3 model). Total estimated emissions of CO, CO2, SOx, NOx and particulate matter (subdivided in elementary carbon (EC), organic carbon (OC), sulphate and ash) for the study domain in 2015 were, respectively, 49 ktonnes y-1, 30000 ktonnes y-1, 360 ktonnes y-1, 710 ktonnes y-1, 4.5 ktonnes y-1, 11 ktonnes y-1, 32 ktonnes y-1 and 3.3 ktonnes y-1. Shipping emissions increased SO2 and NO2 concentrations especially near port areas and also increased the O3, sulphate, and particulate matter (PM2.5 and PM10) concentrations around all over the Iberian Peninsula coastline (especially in the south coastal region). Shipping emissions were responsible for exceedances of WHO air quality guideline for PM2.5 in areas far from the coastline, which confirms that shipping emissions can contribute negatively to air quality, both in coastal and in inland areas.

Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2

The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800 °C. Above 600 °C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500 °C and is completely oxidized above 700 °C.

Carbon Deposition Simulation in Porous SOFC Anodes: A Detailed Numerical Analysis of Major Carbon Precursors

Solid oxide fuel cells (SOFCs) can be operated on a wide range of fuels, including hydrocarbons. Such a fuel supply includes the risk of carbon formation on the catalytically active nickel centers within the porous anodic substrate. Coking is very critical for the reliability and durability of the SOFCs. Thus, within this study, coking propensity of the most prominent carbon containing fuels was analyzed by thermodynamic equilibrium calculations for two fundamentally different types of carbon and detailed transient numerical simulations based on heterogeneous reforming kinetics. This approach is new to the literature and reveals the strengths and weaknesses of both fundamentally different approaches. It was shown that in thermodynamic equilibrium calculations, carbon formation is most likely due to pure methane. Carbon monoxide will form the least amounts of carbon in typical SOFC temperature ranges. Furthermore, based on a validated computational fluid dynamics (CFD) simulation model, detailed heterogeneous reaction kinetics were used to directly simulate elementary carbon adsorbed to the reactive substrate surface. The amounts, spatial and temporal distribution, of carbon atoms within the porous structure were identified between 600 °C and 1000 °C for a broad steam-to-carbon ratio range of 0.5–2. It was shown that most carbon is formed at the beginning of the substrate. A key finding was that steady-state results differ greatly from results within the first few seconds of fuel supply. An increment in temperature causes a significant increase in the amount of carbon formed, making the highest temperatures the most critical for the SOFC operation. Moreover, it was shown that mixtures of pure methane deliver the highest amounts of adsorbed elementary carbon. Equimolar mixtures of CH4/CO cause second highest surface coverages. Pure carbon monoxide blends led to least significant carbon formations. This work has shown the important contribution that thermodynamic equilibrium calculation results, as well as the outcomes of the detailed CFD simulations, allow to identify suitable operating conditions for the SOFC systems and to minimize the risk of coking on porous anodes.