A center feed system for use in a delayed coking system, the center feed system comprising: a spool configured to be attached to a coke drum and a de-header valve; and an inlet sleeve attached to the spool for supplying residual petroleum byproduct into the spool; characterized in that: the inlet sleeve contains a retractable injection nozzle that slides within the inlet sleeve between an extended position in which the retractable injection nozzle extends out of the inlet sleeve into the interior of the spool, and a retracted position in which the retractable injection nozzle is retracted into the inlet sleeve, wherein when in the extended position, the feed line and the retractable injection nozzle are in fluid connection such that residual petroleum byproduct flows from the feed line, through the retractable injection nozzle, and out through an outlet in the retractable injection nozzle into the spool, and when in the retracted position, the retractable injection nozzle blocks the residual petroleum byproduct from flowing from the feed line into the retractable injection nozzle; and wherein the outlet includes a collar for controlling a flow pattern of the residual petroleum byproduct into the spool. a spool configured to be attached to a coke drum and a de-header valve; and an inlet sleeve attached to the spool for supplying residual petroleum byproduct into the spool; characterized in that: the inlet sleeve contains a retractable injection nozzle that slides within the inlet sleeve between an extended position in which the retractable injection nozzle extends out of the inlet sleeve into the interior of the spool, and a retracted position in which the retractable injection nozzle is retracted into the inlet sleeve, wherein when in the extended position, the feed line and the retractable injection nozzle are in fluid connection such that residual petroleum byproduct flows from the feed line, through the retractable injection nozzle, and out through an outlet in the retractable injection nozzle into the spool, and when in the retracted position, the retractable injection nozzle blocks the residual petroleum byproduct from flowing from the feed line into the retractable injection nozzle; and wherein the outlet includes a collar for controlling a flow pattern of the residual petroleum byproduct into the spool. the inlet sleeve contains a retractable injection nozzle that slides within the inlet sleeve between an extended position in which the retractable injection nozzle extends out of the inlet sleeve into the interior of the spool, and a retracted position in which the retractable injection nozzle is retracted into the inlet sleeve, wherein when in the extended position, the feed line and the retractable injection nozzle are in fluid connection such that residual petroleum byproduct flows from the feed line, through the retractable injection nozzle, and out through an outlet in the retractable injection nozzle into the spool, and when in the retracted position, the retractable injection nozzle blocks the residual petroleum byproduct from flowing from the feed line into the retractable injection nozzle; and wherein the outlet includes a collar for controlling a flow pattern of the residual petroleum byproduct into the spool.