Replacement Ammonia and Benzol Scrubbers and associated plant items. The project demanded a series of major lifts and tie-ins in and around existing infrastructure during ongoing production, the timing of which was critical in maintaining the supply of fuel gas to the steel mills. The project involved the removal and replacement of 4no Ammonia and Benzol washer vessels (up to 55m high) and associated pumps, pipework, valves and steelwork, in the MCO By-Products area. The project included the replacement of all DN1200 pipework and recirculating pipework. To enable the removal of the old vessels, existing platform steelwork had to be temporarily supported so it could be partially removed and allow the other vessels to remain in service. The old vessels were removed in sections with the new vessel lifted in in one piece. This allowed the reaming washers to stay in service. All cutting was carried out using cold working.