NUMERICAL MODELLING OF BLAST FURNACE GAS FLOW IN WATER SEPARATOR

Blast furnace gas, which is created as a by-product during the ironmaking, belongs to the less valuable fuels due to its low heating value. Due to BF gas parameters (high amount of gas and high content of CO), it is used as an energy source for the preparation of preheated air in the stoves or for the heating of industrial furnaces. In addition to low heating value, BF gas contains a large amount of dust. In order to prohibit reduction of the heating value of the gas, the gas must be cleaned by a gas cleaning system. Gas cleaning includes two phases: dry cleaning including dust catcher or cyclone and wet cleaning including scrubber, Venturi tubes and water separator (demister, droplet separator). The water separator is a cylindrical vessel with a diameter of 4 to 6 m and a total height of 25 m. During the gas flow in the separator, the water droplets and dust particles are trapped and deposited on the walls, and subsequently carried away in the form of sludge at the bottom of the separator. The main problem with gas cleaning in the separator is the location (shape, dimensions) of the inlet and outlet of gas to and from the separator. In order to achieve the maximum gas cleaning efficiency, a primary simulation of the gas flow through the separator was performed by numerical modelling in the CFD program ANSYS Fluent. In the following stages, optimization of the internal arrangement of the separator will be carried out.