Method and apparatus for removing mercury from contaminated pipes and installation parts, in particular mercury introduced by natural gas

US5529605A · kind A · utility

Assignee

• BEB Erdgas und Erdol GmbH · DE

Inventors

• Siegfried Müssig · Bad Nenndorf, DE
• Hans Kaast · Kleinburgwedel, DE
• Friedrich Schlemm · Hannover, DE

Key dates

• Filing date: Sep 17, 1993
• Grant date: Jun 25, 1996
• Expiry date: Sep 17, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/0419
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Pipe lines for conducting natural gas become contaminated, over a period of time, by an accumulation of mercury, which occurs in minute amounts in natural gas. If used pipe is scrapped, for example by melting, mercury vapor escaping to the atmosphere poses a health hazard. To remove mercury, sections of pipe are closed at both ends by plugs having nipples for connection to a closed circuit and inert gas line connected with a pump for evacuating the line and with a source of inert gas, for example nitrogen. The closed circuit inert gas line contains a blower for circulating the inert gas repeatedly through the pipe sections and a condenser for condensing mercury vapor. The closed circuit further includes a heat exchanger for removing heat upstream of the condenser, a coordinated heat exchanger for restoring heat removed and an additional heater. The pipe sections are heated externally by an oven or internally by heated inert gas.