Process and plant for producing synthetic paraffinic kerosene as jet fuel

A method of retrofitting an existing hydroprocessing plant, the hydroprocessing plant comprising:

• a dewaxing reactor, a hydrogenation reactor, and a separation section arranged downstream at least the dewaxing reactor;
• the method of retrofitting comprising:
• installing a first oligomerization reactor upstream the dewaxing reactor, in which the first oligomerization reactor is arranged to receive an ethylene stream and at least a portion of a second stream of C2 olefins, from a downstream first separation section;
• the first oligomerization reactor comprising an oligomerization catalyst, the oligomerization catalyst being a homogeneous catalyst comprising:
• a transition metal compound or complex comprising at least one of Ti, Zr, Cr, Ni, together with an alkyl aluminum compound dissolved in a hydrocarbon solvent or an etheral solvent;
• or an alkyl aluminum compound dissolved in a hydrocarbon solvent or an etheral solvent, optionally as a co-catalyst;
• the first oligomerization reactor further being arranged to provide a first stream of linear alfa olefins (LAOs) in the C2-C20 range of which at least 80 wt % having a Schultz-Flory distribution with a chain propagation probability (alpha) of from 0.35-0.60, or a Poisson distribution with a chain propagation probability (lambda) of from 1.0-4.7;
• installing the first separation section downstream and in direct fluid communication with the first oligomerization reactor, in which the first separation section is arranged to receive:
• the first stream of LAOs and provide:
• the second stream of C2 olefins, a third stream of C4-C6 olefins, and a fourth stream of C8+ olefins;
• installing a conduit in direct fluid communication between the first separation section and the first oligomerization reactor, for recycling the at least a portion of second stream of C2 olefins to the first oligomerization reactor;
• installing a second oligomerization reactor, arranged to operate at conditions for trimerization downstream the first separation section;
• further, installing a conduit in direct fluid communication between the first separation section and the second oligomerization reactor for supplying the third stream of C4-C6 olefins to the second oligomerization reactor, and in which the second oligomerization is further arranged to provide a fifth stream of branched C12-C18 olefins;
• installing a conduit in direct fluid communication between the second oligomerization reactor and the hydrogenation reactor which is arranged downstream for supplying the fifth stream of branched C12-C18 olefins, and in which the hydrogenation reactor is further arranged to provide a sixth product stream of branched C12-C18 isoparaffins;
• installing a conduit in direct fluid communication between the first separation section and the dewaxing reactor which is arranged downstream for supplying the fourth stream of C8+ olefins to the dewaxing reactor, and in which the dewaxing reactor is further arranged to provide a seventh product stream of branched C8-C20 isoparaffins;
• installing a conduit in direct fluid communication between the hydrogenation reactor and the separation section arranged downstream at least the dewaxing reactor for supplying the sixth product stream of branched isoparaffins;
• and further installing a conduit in direct fluid communication between the dewaxing reactor and the separation section arranged downstream for supplying the seventh product stream of branched C8-C20 isoparaffins;
• the separation section is further arranged to provide:
• an eighth stream of light end compounds;
• and a nineth product stream as synthetic paraffinic kerosene (SPK), the SPK having:
• i) a Branching Index, BI, defined as the average number of carbon atoms in the side chains divided by the average number of carbon atoms in the main chain, higher than 0.10, and ii) a freezing point below −40° C.;
• optionally, installing a hydrogen producing unit (HPU) or a gasification unit (GU) in direct or indirect fluid communication with the separation section arranged downstream at least the dewaxing reactor;
• the HPU being arranged to receive at least a portion of the eighth stream of light end components, and provide a make-up hydrogen stream;
• and
• installing a conduit for providing at least a portion of the make-up hydrogen gas to any of the dewaxing reactor or hydrogenation reactor.