Influence of ESP collector configuration on reduction of particulate emissions from biomass combustion facility

Development of compact electrostatic precipitators (ESPs) for reduction of particulate emissions from small scale biomass combustion is an actual task. Particle mass collection efficiency of an ESP depends from combustion conditions, geometry of precipitator ionizer, collector stage configuration and ESP operation parameters. The investigation of the influence of collector stage configuration on particle mass collection efficiency of a pilot space charge ESP was in the focus of the study. It was shown that the use of tube collector with integrated grounded plates enhanced particle mass collection efficiency. The loading of plates with aerosol provoked particle re-entrainment and decreased long-term ESP mass collection efficiency. The use of grounded brush electrodes ensured effective reduction of particle emissions but resulted in increase of pressure drop in the precipitator. The optimization of cleaning intervals of the ionizer and collector stages increased particle mass collection efficiency. It was shown, that the integration of automatic systems for ionizer and collector cleaning into the space charge ESP enhanced precipitator long-term operation stability and ensured effective reduction of particulate emissions form small scale biomass combustion

Agglomeration State of Titanium-Dioxide (TiO2) Nanomaterials Influences the Dose Deposition and Cytotoxic Responses in Human Bronchial Epithelial Cells at the Air-Liquid Interface

Extensive production and use of nanomaterials (NMs), such as titanium dioxide (TiO(2)), raises concern regarding their potential adverse effects to humans. While considerable efforts have been made to assess the safety of TiO(2) NMs using in vitro and in vivo studies, results obtained to date are unreliable, possibly due to the dynamic agglomeration behavior of TiO(2) NMs. Moreover, agglomerates are of prime importance in occupational exposure scenarios, but their toxicological relevance remains poorly understood. Therefore, the aim of this study was to investigate the potential pulmonary effects induced by TiO(2) agglomerates of different sizes at the air–liquid interface (ALI), which is more realistic in terms of inhalation exposure, and compare it to results previously obtained under submerged conditions. A nano-TiO(2) (17 nm) and a non-nano TiO(2) (117 nm) was selected for this study. Stable stock dispersions of small agglomerates and their respective larger counterparts of each TiO(2) particles were prepared, and human bronchial epithelial (HBE) cells were exposed to different doses of aerosolized TiO(2) agglomerates at the ALI. At the end of 4h exposure, cytotoxicity, glutathione depletion, and DNA damage were evaluated. Our results indicate that dose deposition and the toxic potential in HBE cells are influenced by agglomeration and exposure via the ALI induces different cellular responses than in submerged systems. We conclude that the agglomeration state is crucial in the assessment of pulmonary effects of NMs

Study of electrohydrodynamic phenomena in high temperature high pressure nitrogen

The study of corona discharge current-voltage characteristics (CVCs) in high temperature high pressure (HTHP) gases is an important step in development of compact HTHP electrostatic equipment. The scope of the current work was the study of corona discharge CVCs in HTHP nitrogen. Corona discharge ionizer was installed inside of a HTHP casing. Ionizer included star-shaped high voltage electrodes installed inside of a grounded tube electrode. The grounded electrode could be heated. Tests were carried out at various gas pressure and grounded electrode temperatures. The CVC-direct and CVC-indirect characteristics were measured for positive and negative polarity of applied voltage. For the same values of applied voltage, current for negative corona was higher than for positive one. The increase of gas pressure stabilized corona discharge and increased corona onset voltage. Operation of the ionizer at CVC-indirect ensured stable corona discharge. Corona discharge CVCs have shown hysteresis loop which area depended on gas pressure and temperature