Upgrade natural gas condensate and other contaminated streams to higher-value ethylene plant feedstocks. Mercury, arsenic and lead contamination in potential ethylene plant feedstocks precludes their use, despite attractive yield patterns. The contaminants poison catalysts, cause corrosion in equipment and have undesirable environmental implications. For example, mercury compounds poison hydrogenation catalysts and, if present in the steam-cracker feed, are distributed in the C2–C5 + cuts. A condensate containing mercury may have negative added-value as a gas field product.
Two RAM processes are available. In the presence of metallic mercury, a RAM I adsorber will be effective. In the presence of organo metallic mercury and/or arsenic and/or lead, a two-stage process (called RAM II) will effectively purify the stream, whatever its endpoint.
The RAM II process configuration is as follows: Feed is mixed with H2 make-up and heated up in (1) to a first catalytic reactor (2) in which organometallic mercury compounds are converted to elemental mercury, and organic arsenic compounds are converted to arsenic-metal complexes and trapped in the bed. Lead, if any, is also trapped on the bed. The second reactor (3) contains a specific mercury-trapping mass. There is no release of the contaminants to the environment, and spent catalyst and trapping material can be disposed of in an environmentally acceptable manner.
