Process enhancing adsorbent capacity for acetylenic compounds

Abstract

Processes using heterogeneous adsorbents are disclosed for purification of olefins such as are typically produced by thermal cracking of suitable hydrocarbon feedstocks, by providing a impure mixture comprising at least one olefin of from 2 to about 8 carbon atoms, acetylenic impurities having the same or similar carbon content in an amount of up to about 1 percent by volume base upon the total amount of olefin present and optionally saturated hydrocarbon gases; admixing a source of dihydrogen with the impure mixture to form a feedstream comprising a sub-stoichiometric amount of dihydrogen based upon conversion of the total amount of acetylenic impurities present to their olefinic analogs; and passing the feedstream through a particulate bed of adsorbent comprising predominantly a support material on which is dispersed at least one metallic element in the zero valent state, to effect, under conditions suitable for adsorption within the bed, selective adsorption and/or complexing of the contained acetylenic contaminants with the adsorbent, and thereby obtain purified olefinic product which contains less than about 1 part per million by volume of the acetylenic impurities. Thereafter the resulting bed of adsorbent is regenerated in the presence of a reducing gas containing dihydrogen to effect release of the contained acetylenic impurities from the adsorbent.