Residues, removal from pipelines

Essentially all of the methane [74-82-8] is removed ia the demethanizer overhead gas product. High recovery of ethane and heavier components as demethanizer bottoms products is commonplace. The work that is generated by expanding the gas ia the turboexpander is utilized to compress the residue gas from the demethanizer after it is warmed by heat exchange with the inlet gas. Recompression and deUvery to a natural gas pipeline is performed downstream of the plant. A propane recovery of 99% can be expected when ethane recoveries are ia excess of 65%. 

A metallurgical plant using an ore will invariably produce solid residue after the metal values have been removed from the ore. The residue from pyro plants may be disposed of by trucking or conveying, based on techno-economics and feasibility. However, pipeline conveyances of the residue slurry is also in vogue for certain applications where residue quantities are fairly large. 

Many hazardous operations require the use of pipelines to convey product material from one location to another. In time, these pipelines become lined with the hazardous product to the extent they could serve as a media for propagation of an incident from station to station. Therefore, periodically cleaning these lines of the hazardous residue is important to operational safety. Additionally, removing accumulations of residue in the pipelines will increase flow volume, operating efficiency, and will minimize the possibility of product contamination. 

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