Fluidized bed reactor system for catalytic cracking of light hydrocarbons

A continuous process, comprising:

• receiving, in a top portion of a fluidized bed reactor, a heated light hydrocarbon feed stream flowing upwards and a heated regenerated catalyst at a temperature sufficient to crack the heated light hydrocarbon feed stream to produce a first product effluent stream comprising hydrogen and spent catalyst comprising coke deposits;
• combusting, in a catalyst regeneration unit operatively connected to a bottom portion of the fluidized bed reactor, the spent catalyst comprising the coke deposits to produce the heated regenerated catalyst and a heated gas effluent;
• mixing a light hydrocarbon feed stream with the heated gas effluent to produce the heated light hydrocarbon feed stream, the mixing comprising flowing the heated gas effluent upwards in the catalyst regeneration unit to a point of injection of the light hydrocarbon feed stream above the catalyst regeneration unit where the heated gas effluent and the light hydrocarbon feed stream are mixed;
• and
• flowing, in a riser externally connected to the catalyst regeneration unit and the fluidized bed reactor, the heated regenerated catalyst from the catalyst regeneration unit with a gas-based stream to the top portion of the fluidized bed reactor to contact the heated light hydrocarbon feed stream flowing upwards to produce a second product effluent stream comprising hydrogen and additional spent catalyst comprising coke deposits.