Showing papers by "Young I. Cho published in 2004"

Physical water treatment for fouling prevention in heat exchangers

Abstract: Publisher Summary Physical water treatment (PWT) is an attempt to treat hard water for the purpose of preventing or mitigating fouling using a physical means, without adding chemicals to water. PWT technology prevents or mitigates scale build-up at heat exchangers. The fouling problem starts because of hard water being heated inside heat transfer equipment. The precipitation of dissolved mineral ions and subsequent scale deposit on the heat transfer surface critically depend on water chemistry. In addition to water chemistry, the deposit and removal rates of scale also depend on flow velocity, heat flux, and heat exchanger geometry. The central hypothesis of PWT is bulk precipitation. This chapter focuses on the science behind bulk precipitation, which leads to particulate fouling that produces a soft sludge coating on the heat transfer surface. Thus, for the successful operation of PWT, the ability to remove the soft sludge coating is essential. The various mechanisms of physical water treatment–such as effect of electric and magnetic fields, separation of charges, PWT works at surface via heterogeneous catalysis, and bulk precipitation–along with effect of particles in water on fouling mitigation have been discussed. The chapter also describes the validation methods for the efficiency of PWT and issues involved in the validation of PWT. It is essential to identify the conditions where PWT does and does not work, which in turn helps to understand the fundamental mechanism of PWT. The effectiveness of PWT at laboratory tests, in general, depends on the test conditions, including the flow velocity through permanent magnets, water hardness, and recirculation.

Vortex reactor and method of using it

Abstract: A vortex reactor is provided. The vortex reactor includes a reaction chamber formed by a frustum-shaped portion, the narrower part of which is downwardly oriented. Proximate to the narrower part of the frustum-shaped portion, the vortex reactor includes apparatus for creating an axial gas flow and apparatus for creating a circumferential gas flow. The vortex reactor also includes a particulate solid inlet for feeding particulate solids to the reaction chamber. The vortex reactor may optionally include apparatus for generating plasma in the reaction chamber by providing a gliding arc electrical discharge in the reaction chamber. Also provided is a method of processing particulate solids using the vortex reactor of the invention. A reverse vortex plasma reactor (TSAPG) is also provided.

Plasma reactor for the production of hydrogen-rich gas

Abstract: A plasma reactor (10) is provided. The plasma reactor (10) includes a reaction chamber (12) formed by a wall (13). Proximate to the first end of the reaction chamber, the plasma reactor includes a feed gas inlet (14) for creating a reverse vortex gas flow (16) in the reaction chamber. The plasma reactor (10) also includes an anode and a cathode connected to a power source for generation of an electric arc for plasma generation in said reaction chamber. The plasma reactor (10) may optionally include a movable electrode adapted for movement from a first, ignition position to a second, operational position in the reaction chamber. Also provided is a method of converting light hydrocarbons to hydrogen-rich gas, using the plasma reactor of the invention.