Caracterização de estudos de impacto ambiental relacionados ao cultivo e expansão da cultura da soja no mundo

A sojicultura é caracterizada como a monocultura de maior dimensão econômica mundial. Esse fato tem despertado o desenvolvimento de pesquisas em nível mundial, cuja finalidade é compreender os impactos negativos do processo de expansão de seu cultivo. Este artigo tem por objetivo apresentar o mapeamento da produção científica internacional sobre os impactos negativos decorrentes do cultivo e expansão da cultura da soja. O escopo da pesquisa é composto por 389 artigos, coletados das bases de dados Scielo e Web of Science. Os resultados são apresentados sob as perspectivas de: 1) distribuição anual dos artigos; 2) caracterização dos artigos mais citados; 3) países que mais publicaram; e 4) clusters de palavras-chave. Foi possível perceber uma elevação da concentração de publicações a partir do ano de 2000, principalmente relacionadas ao bioma Amazônia. Os países que mais publicaram no período analisado foram os Estados Unidos, Brasil e China. A co-ocorrência de palavras-chave mais utilizadas foi “deforestation, systems, brazil, assessment, soybean oil, soybean biodiesel”. Dos 389 artigos encontrados, observou-se que a pesquisa está centrada nos estudos relacionados ao desmatamento, aumento da produção de biodiesel, contaminação dos recursos hídricos, mudanças climáticas e o uso dos agrotóxicos, entretanto há estudos crescentes sobre os impactos positivos no ambiente com enfoque em novas tecnologias, como a integração lavoura-pecuária e floresta, nos sistemas de produção para a mitigação de danos ao meio ambiente, sobretudo com o potencial para o sequestro de carbono, além de orientarem para o uso racional dos recursos hídricos.

Investigation of the impact of injection timing and pressure on emissions characteristics and smoke/soot emissions in diesel engine fuelling with soybean fuel

Engine injection strategy and renewable fuel both can improve nitrogen oxides (NOX) and smoke/soot emissions in a common-rail compression ignition (CI) diesel engine. The effects of different postinjection (PI) timings (15, 30, and 45) after top dead center (aTDC) and injection pressures (550 and 650 bar) on pollutant emissions and smoke/soot emissions were investigated for combustion of a renewable fuel (soybean biodiesel). The results showed that the levels of carbon monoxide (CO), hydrocarbons (HCs), and NOX are reduced from the combustion of soybean biodiesel compared to the diesel fuel combustion for different injection strategy. Besides, NOX emission is clearly reduced with retarded PI timing, especially at 45°. It is found that the increasing injection pressure reduced gaseous emissions for both fuels. The combination between biodiesel fuel and injection strategy can provide meaningful improvements in pollutant emissions, as well as enhance the exhaust temperature compared to the diesel fuel. With biodiesel fueling, smoke/soot emissions were reduced from biodiesel combustion (by 19.7%) under different fuel injection timings and pressures rather than from the diesel fuel combustion (by 12.2%).

Influence of Silica Nano-Additives on Performance and Emission Characteristics of Soybean Biodiesel Fuelled Diesel Engine

The present study examines the effect of silicon dioxide (SiO2) nano-additives on the performance and emission characteristics of a diesel engine fuelled with soybean biodiesel. Soybean biofuel was prepared using the transesterification process. The morphology of nano-additives was studied using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The Ultrasonication process was used for the homogeneous blending of nano-additives with biodiesel, while surfactant was used for the stabilisation of nano-additives. The physicochemical properties of pure and blended fuel samples were measured as per ASTM standards. The performance and emissions characteristics of different fuel samples were measured at different loading conditions. It was found that the brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) increased by 3.48–6.39% and 5.81–9.88%, respectively, with the addition of SiO2 nano-additives. The carbon monoxide (CO), hydrocarbon (HC) and smoke emissions for nano-additive added blends were decreased by 1.9–17.5%, 20.56–27.5% and 10.16–23.54% compared to SBME25 fuel blends.

Influence of Silica Nano-Additives on Performance and Emission Characteristics of Soybean Biodiesel Fuelled Diesel Engine

The present study examines the effect of SiO2 nano-additives on the performance and emission characteristics of a diesel engine fuelled with soybean biodiesel. Soybean biofuel was prepared using the transesterification process. Nano-additives characterisations were done using different tests such as FESEM, XRD, EDS, etc., to study the morphology of nano-additives. For proper blending of nano-additives with biodiesel, the ultrasonication process was used. Surfactant was used for the stabilisation of nano-additives. After making all the combinations of nano fuel blends, physicochemical properties were measured as per ASTM standards. Performance and emissions readings were taken at different load conditions. It was found that with the addition of SiO2 nano-additives, brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) was increased by 3.48-6.39% and 5.81-9.88%, respectively. Significant reduction of CO, CO2, NOx, and smoke emissions were also observed compared to baseline fule due to better combustion efficiency with the use of SiO2 nano-additive.