유기성 폐기물 교반압력용기 내 부하가 교반축 안전성에 미치는 영향에 관한연구

Abstract

Modern society has been experiencing by population growth and urbanization that bring, a change of eating habits which has occurred a various types of waste in a large amount. Even though these wastes are required an immediate treatment with difficulties unsanitary handling and existing waste treatment method are by incineration, fermentation, drying and etc. however a bad smell occurs after the treatment that need's a lot of energy in processing organic wastes with high moisture contents and wasteful and inefficient problem. The pressure vessels agitating an organic waste such as daily waste, food waste, and the others kind of organic waste can recycle in combination with processed food, compost, and fuel. The strength assessment of the organic waste agitating vessel is required in terms of safety due to the differences of loading on the shaft that was treated by agitating the mixture of food waste. The damage of agitating axis is depended on steam pressure, temperature condition and the force moment that exerted by the food waste. Thus the strength assessment and stability evaluation are very important, espescially to handle a hard waste. In this study the rotation capacity of agitation is about 5 tons considering general structural rolled steel pressure vessel strength and steam pressure. The purpose is to estimate the safety and strength evaluation for a agitator axis and impellers according to the rotating angle of the axis under the condition of the 3.2 ton capacity reactor. analysis was performed by FEM ANSYS program, and the agitation axis were modelled using the CATIA 3D operations. The results of this study will be used as a basic data. The following conclusions could be drawn from this study. 1) The maximum von Mises stresses were obtained as 44.389 MPa, 43.609 MPa and 41.353 MPa respectively for the rotation angles are 15°, 30°and 45° at steam pressure 1.3 MPa. and when the pressure is 1.96 MPa, the maximum value was obtained as 51.601 MPa, 50.821 MPa, and 48.564 MPa.

2) at the steam pressure 1.3 MPa and 1.96 MPa, as the rotation angle decreases stress goes to the long agitator's maximum stress becomes twice. The differences in stress value on a short agitating impeller maybe seems doesn’t appear, but in the long agitating impellers it’s shown difference due to impellers.

3) The safety factor of the organic waste agitating pressure vessel was obtained as 6.19∼6.65 ect the pressure 1.3 MPa and it was obtained 5.3∼5.66 at 1.96 MPa. Therefore the organic waste agitating pressure vessel in study has sufficient safeness for operation.