Removal of Mercury From Ethylene Plant Feedstocks and Cracked Gas Streams

Mercury embrittles Al and Al alloys and causes equipment failures in plants where these metals are used. In this review, we study the recent patents and commercial and near-commercial technologies for eliminating mercury from process streams. We compare the advantages and disadvantages of each process, and we also provide cost estimates for three processes to remove mercury from ethylene plant feedstock and cracked gas streams. One process (Calgon Carbon) operates in the vapor phase at 95% mercury removal efficiency; two processes (Stamicarbon and IFP) operate in the liquid phase at 97+% and 99+% removal efficiencies, respectively.

Cost estimates are presented for a 500,000 t/yr ethylene plant that uses high Hg-content natural gas condensates as feedstocks.