Vapor/liquid separation apparatus for use in cracking hydrocarbon feedstock containing resid

A vapor/liquid separation apparatus for treating a flow of vapor/liquid mixtures of hydrocarbons and steam, comprising:

• (a) a substantially cylindrical vertical drum having an upper cap section, a middle section comprising a circular wall, and a lower cap section;
• (b) an overhead vapor outlet attached to said upper cap section;
• (c) at least one substantially tangentially positioned inlet in the circular wall of said middle section for introducing said flow along said wall;
• (d) an annular structure located in the middle section, comprising i) an annular ceiling section extending from the circular wall and ii) an internal vertical side wall to which said ceiling section extends, said side wall being positioned substantially concentrically to, but away from, said circular wall, said annular structure blocking the upward passage of said vapor/liquid mixtures along the circular wall beyond said ceiling section, and said annular structure surrounding an open core having sufficient cross-sectional area to permit vapor velocity low enough to avoid significant entrainment of liquid;
• and
• (e) a substantially concentrically positioned, substantially cylindrical boot of less diameter than said middle section, said boot communicating with said lower cap section, and further comprising a liquid outlet at its lower end.