Wyniki wyszukiwania - BazTech

1

Effects on of blended biodiesel and heavy oil on engine combustion and black carbon emissions of a low-speed two-stroke engine

Wei Cunfeng, Jiang Guohe, Wu Gang, Zhou Yu, Liu Yuanyuan

Polish Maritime Research

|

2024

|

nr 1

94--101

EN

The effects of heavy fuel oil and biodiesel blends on engine combustion and emissions were studied in a marine twostroke diesel engine. The engine was operated under propeller conditions using five different fuels with biodiesel blends of 10% (B10), 30% (B30), 50% (B50), and sulphur contents of 0.467% low sulphur fuel oil (LSFO) and 2.9% high sulphur fuel oil (HSFO). Tests have shown that using a biodiesel blend increases the engine fuel consumption due to its lower calorific value. Heavy fuel oil has a high Polycyclic aromatic hydrocarbons (PAH) content, which leads to higher exhaust temperatures due to severe afterburning in the engine. A comparison of engine soot emissions under different fuel conditions was carried out, and it was found that the oxygen content in biodiesel promoted the oxidation of soot particles during the combustion process, which reduced the soot emissions of biodiesel. Compared to HSFO, B10, B30, B50 and LSFO, the soot emission concentrations were reduced by 50.2%, 56.4%, 61% and 37.4%, respectively. In our experiments, the soot particles in the engine exhaust were sampled with a thermal float probe. Using Raman spectroscopy analysis, it was found that as the biodiesel ratio increased, the degree of carbonisation of the soot particles in the exhaust became less than that in the oxygenation process, resulting in a decrease in the degree of graphitisation.

2

Indirect estimation of black carbon concentration in traffic site based on other pollutants : time variability analysis

Kamińska Joanna A., Kazak Jan K.

Journal of Water and Land Development

|

2023

|

no. 58

1--10

EN

Aiming to create more sustainable cities it is necessary to understand and manage different ecological factors which influence human health. One of such factors is black carbon (BC) in atmosphere, which currently is not commonly monitored by environmental monitoring systems. The aim of this research was to estimate by indirect approach the relation between eBC (equivalent of black carbon) concentration and other air pollutants in order to define approximate level of eBC in more efficient approach. The study was conducted in Wrocław (Poland) in October 2021, and combined data on eBC concentration (measured by microaethalometer), air quality (from national environmental monitoring system) and traffic (from municipal traffic management system). Quantile regression was used to assess the relationship between the concentrations of pollutants. The obtained results show that for rise 1 mg∙m-3 of carbon monoxide, eBC concentration rise between 4.2 and 8.0 μg∙m-3, depending on the period of a day. Precision of eBC concentration evaluation is influenced by sun light which results in higher precision of defining a scaling factor for night hours. Outcomes of this study constitute an added value to understanding of interconnections between different factors describing environmental conditions in cities and might be helpful for more effective environmental assessment of human habitats.

3

Using the DDA (Discrete Dipole Approximation) Method in Determining the Extinction Cross Section of Black Carbon

Skorupski K.

Metrology and Measurement Systems

|

2015

|

Vol. 22, nr 1

153--164

EN

BC (Black Carbon), which can be found in the atmosphere, is characterized by a large value of the imaginary part of the complex refractive index and, therefore, might have an impact on the global warming effect. To study the interaction of BC with light often computer simulations are used. One of the methods, which are capable of performing light scattering simulations by any shape, is DDA (Discrete Dipole Approximation). In this work its accuracy was estimated in respect to BC structures using the latest stable version of the ADDA (vr. 1.2) algorithm. As the reference algorithm the GMM (Generalized Multiparticle Mie-Solution) code was used. The study shows that the number of volume elements (dipoles) is the main parameter that defines the quality of results. However, they can be improved by a proper polarizability expression. The most accurate, and least time consuming, simulations were observed for IGT_SO. When an aggregate consists of particles composed of ca. 750 volume elements (dipoles), the averaged relative extinction error should not exceed ca. 4.5%.

4

Effect of synoptic meteorological conditions on aerosol properties over urban environment: A study over tropical urban region of Hyderabad, India

Kharol S.K., Badarinath K.V.S.

Acta Geophysica

|

2007

|

Vol. 55, no. 3

383-397

EN

Aerosol particle size distribution and chemical properties are important in studies related to human health and climate. The present study describes an analysis of aerosol mass loading, Aerosol Optical Depth (AOD), black carbon aerosol mass concentration and carbon monoxide over tropical urban region of Hyderabad, India, during March 2006, coinciding with active forest fires season over India. Aerosol optical depth, particulate matter mass loading and carbon monoxide were observed to be high on days with air mass coming from north of the study area. Spatial occurrence of forest fires was analysed using MODIS daytime data and DMSP-OLS nighttime data sets. Aerosol optical depth measured using Micro-tops–II sunphotometer correlated well with MODIS derived AOD values. Results of the study suggested that synoptic meteorological conditions play an important role in the observed aerosol properties over the study area during the forest fire season.