Methods and systems for processing hydrocarbon streams

A method of producing an alkene comprising:

• depressurizing an alkane stream to form a mixed phase stream comprising a non-vapor phase hydrocarbon;
• vaporizing at least a portion of the non-vapor phase hydrocarbon to form a vaporized stream;
• separating a first product and a second product from the vaporized stream, wherein (i) the first product comprises at least a portion of the vaporized stream and non-vapor phase droplets, and (ii) the second product comprises at least a portion of the vaporized stream remaining as non- vapor during the vaporization, wherein the separation includes filtration carried out in one or more knock-out drums optionally having a demister pad, a cyclonic device, a vane pack device, or combination(s) thereof;
• removing the non-vapor phase droplets from the first product in a coalescer comprising coalescing elements to form a third product;
• pyrolysing a mixture of the third product with steam under pyrolysis conditions that include a temperature in a range of from about 815° C. to about 925° C. to produce C2+ unsaturates.

A hydrocarbon processing system comprising:

• a depressurization unit configured to reduce a pressure of a hydrocarbon stream;
• a vaporization unit in fluid communication with the depressurization unit and configured to vaporize at least a portion of a non-vapor phase hydrocarbon of the hydrocarbon stream;
• a separation system in fluid communication with the vaporization unit, the separation system comprising a coalescing element;
• and
• a pyrolysis reactor in fluid communication with the separation system.

A system for producing alkenes from alkanes comprising:

• a heat exchanger in fluid communication with an alkane stream feed and configured to heat an alkane stream;
• a depressurization unit in fluid communication with the heat exchanger and configured to reduce a pressure of the alkane stream;
• a vaporizing unit in fluid communication with the depressurization unit and configured to vaporize at least a portion of a non-vapor phase hydrocarbon of the alkane stream;
• a separation system in fluid communication with the vaporizing unit, the separation system comprising coalescing elements;
• and
• a pyrolysis reactor in fluid communication with the separation system.