| 摘要 |
PURPOSE:To enable to effectively clean the heating surface at the cooled side by a method wherein heating fluid is charged to the cooling side and/or the cooled side of the heat exchanger of the titled method to cool scrubbed fluid produced at the scrubbing of high temperature gas. CONSTITUTION:The influence of scale produced on the heating surface at the cooled side of the cooler 9 during the cooling of the scrubbed fluid is measured with a differential pressure gage 13 and a flow meter 14. The flushing of the cooled side of the cooler 9 is performed at the time when the difference of pressure measured with the gage 13 turns to be above the predetermined value or the flow rate measured with the meter 14 turns to be below the predetermined value. In order to flush, firstly, only the supply of raw thermal cracking material is temporarily stopped and the inlet valve 15 and the outlet valve 16 of cooling water are closed, resulting in causing to heat circulating scrubbed fluid 23 and the cooling water in the cooler 9 to a high temperature. As a result, the scrubbed fluid 23 passes while contacting with the heating surface at the cooled side of the cooler 9 and effectively remove from the heating surface scale and the like, which is sent back to a scrubbing tower 10 by being accompanied by the circulating fluid 23. After that, when the difference of pressures turns to be below the predetermined value, the valves 15 and 16 are opened again to flow the cooling water and the supply of raw thermal cracking material is started again. |
