Patent ID: 7956231

Claim:
A method for separation of olefins having three carbon atoms from olefins having four carbon atoms, said method comprising: introducing a crude hydrocarbonaceous feed gas containing olefins into a C3/C4 separation stage, operated at crude gas pressure, and a depropanizer separation column (P) separating olefins having at most three carbon atoms and olefins having at least four carbon atoms, said depropanizer (P) operating at a pressure of 8-12 bar, said crude hydrocarbonaceous feed gas is compressed, precooled, and dried prior to being introduced into said C3/C4 separation stage, and wherein, after being precooled and dried, a part (R 1 ) of said crude gas is introduced into an absorber (C4A) and another part (R 2 ) of said crude gas is introduced directly into said depropanizer (P), said C4 absorber produces a fraction having at least three carbon atoms (C3+), and another fraction having at most three carbon atoms (C3−), said depropanizer produces a fraction having at most three carbon atoms (C3−) and another fraction having at least four carbon atoms (C4+), at least a portion of said fraction having at most three carbon atoms (C3−) from said absorber is introduced into said depropanizer (P), and at least a portion of said fraction having at most three carbon atoms (C3−) from said depropanizer is recycled to said C4 absorber.