| 摘要 |
<p>To remove mercury from the inner surfaces of tubing, esp. dismantled gas carrier piping, the pipe with the contaminated inner surface is heated to a temp. so that, according to the gas pressure in the pipe, the partial vapour pressure of the mercury gives a through evaporation of any mercury adhering to the surface and in pores and cracks in the inner pipe wall. An inert gas is passed in a continuous flow through the pipe to carry out the mercury vapour for the mercury to be separated in a cold pptn. Also claimed is an assembly with a closure system (2,3) to seal the ends of one or more pipes (1), with feed and exhaust channels (4,5) for an inert gas. At least one cold precipitating unit (6) is connected to the inert gas exhaust (5) to condense the mercury. A suction fan (7) moves the inert gas in the pipe (1) and the condenser (6), and through a heater (10) acting externally on the pipe (1). USE/ADVANTAGE - The method is for the removal of mercury present in dismantled piping used to carry natural gas from Zechstein and Bunter sandstone levels. The piping is of steel, or can be plastics or glass, where mercury can be present at levels of several 100 micrograms per Nm3 and build up on the inner wall of the piping. The mercury is removed and collected safely, without damage to the environment.</p> |
