Performance Characteristics between Horizontally and Vertically Oriented Electrodes EHD-ESP for Collection of Low-Resistive Diesel Particulates

Abstract --The novel electrohydrodynamically-assisted electrostatic precipitator (EHD ESP) was developed to suppress particle reentrainment for collection of low resistive diesel particulates. The collection efficiency was compared between vertically and horizontally oriented electrodes of the EHD ESP using 400 cc diesel engine. The particle size dependent collection efficiency was evaluated for the particle size ranging in 20 to 5,000 nm using a scanning mobility particle sizer (SMPS) and a particle counter (PC). Both horizontally and vertically oriented EHD ESP showed an excellent suppression of particle reentrainment. However, the horizontally oriented electrode EHD ESP showed significantly improved for the particle size of 300-500 nm in comparison with vertically oriented electrode EHD ESP, resulting in more than 90% collection efficiency for all particle size range. The EHD ESP has high potential especially for highly concentrated marine diesel engine emission control

Plasma Processes for Renewable Energy Technologies

The use of renewable energy is an effective solution for the prevention of global warming. On the other hand, environmental plasmas are one of powerful means to solve global environmental problems on nitrogen oxides, (NOx), sulfur oxides (SOx), particulate matter (PM), volatile organic compounds (VOC), and carbon dioxides (CO2) in the atmosphere. By combining both technologies, we can develop an extremely effective environmental improvement technology. Based on this background, a Special Issue of the journal Energies on plasma processes for renewable energy technologies is planned. On the issue, we focus on environment plasma technologies that can effectively utilize renewable electric energy sources, such as photovoltaic power generation, biofuel power generation, wind turbine power generation, etc. However, any latest research results on plasma environmental improvement processes are welcome for submission. We are looking, among others, for papers on the following technical subjects in which either plasma can use renewable energy sources or can be used for renewable energy technologies: Plasma decomposition technology of harmful gases, such as the plasma denitrification method; Plasma removal technology of harmful particles, such as electrostatic precipitation; Plasma decomposition technology of harmful substances in liquid, such as gas–liquid interfacial plasma; Plasma-enhanced flow induction and heat transfer enhancement technologies, such as ionic wind device and plasma actuator; Plasma-enhanced combustion and fuel reforming; Other environment plasma technologies

A review on regulations, current status, effects and reduction strategies of emissions for marine diesel engines

Marine diesel engines, which provide main power source for ships, mainly contribute to air pollution in ports and coastal areas. Thus there is an increasing demand on tightening the emission standards for marine diesel engines, which necessitates the research on various emission reduction strategies. This review covers emission regulations and emission factors (EFs), environmental effects and available emission reduction solutions for marine diesel engines. Not only the establishment of the emission control areas (ECAs) in the regulations but also many experiments show high concerns about the sulfur limits in fuels, sulfur oxides (SOx) and nitrogen oxides (NOx) emissions. Research results reveal that NOx emissions from marine diesel engines account for 50% of total NOx in harbors and coastal regions. Sulfur content in fuel oil is an important parameter index that determines the development direction of emission control technologies. Despites some issues, biodiesel, methanol and liquefied nature gas (LNG) play their important roles in reducing emissions as well as in replacing fossil energy, being promising fuels for marine diesel engines. Fuel-water emulsion (FWE) and exhaust gas recirculation (EGR) are effective treatment option for NOx emissions control. Common rail fuel injection is an effective fuel injection strategy to achieve simultaneous reductions in particulate matter (PM) and NOx. Selective catalytic reduction (SCR) and wet scrubbing are the most mature and effective exhaust aftertreatment methods for marine diesel engines, which show 90% De-NOx efficiency and 95% De-SOx efficiency. It can be concluded that the integrated multi-pollutant treatment for ship emissions holds great promise

SEPARATION OF FINE LIQUID DROPLETS FROM HIGH SPEED AIR UTILIZING THE ELECTROHYDRODYNAMICS TECHNIQUE

With constant process intensification in recent years, the separation of fine micron and submicron size liquid droplets from gaseous flow mediums has become an important subject for the process and aerospace industries. While conventional technologies are not effective in this droplet size range, electrostatic separation demonstrated remarkable effectiveness and reliability while lowering maintenance and operation cost. However, it is commonly used for low droplet concentration in relatively low velocity gas flow. This current experimental study is focused on electrostatic separation of high concentration of fine electrically conductive droplets from high velocity gas flow. Different separators including wire-to-plate, wire-to-cylinder, single stage, and multi-stage separators were designed, built and tested at gas velocities up to 15 m/sec and droplet concentration up to 22,000 ppm. The results demonstrated that two-stage plate, as well as tubular separators provides maximum separation efficiency at minimum power consumption. However, the tubular separator is easier to package in the required space envelope and 1-inch diameter tubes are more efficient at high velocity and droplet concentrations