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 hydrocracking reactor, and a separation section arranged downstream at least the dewaxing reactor;
• the method of retrofitting comprising:
• installing an oligomerization reactor upstream the dewaxing reactor and the hydrocracking reactor, in which the oligomerization reactor is arranged to receive:
• an ethylene stream and at least a portion of a second stream of C2-C6 olefins from a downstream first separation section;
• the oligomerization rector 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 oligomerization reactor further being arranged to provide a first stream of linear alfa olefins (LAOs) in the C2-C30 range of which at least 80 wt % having a Schultz-Flory distribution with a chain propagation probability (alpha) of 0.49-0.73, or a Poisson distribution with a chain propagation probability (lambda) of 3.5-8.5;
• installing the first separation section downstream and in direct fluid communication with the oligomerization reactor, in which the first separation section is arranged to receive:
• the first stream of LAOs;
• and at least a portion of a sixth product stream of C1-C30 compounds, the C1-C30 compounds comprising branched C8-C18 isoparaffins, linear or branched C8-C30 paraffins, and C1-C7 paraffins, from the hydrocracking reactor which is arranged downstream;
• the first separation section further being arranged to provide:
• the second stream of C2-C6 olefins, a third stream of C8-C18 olefins and paraffins, and a fourth stream of C18-C30+ olefins and paraffins;
• installing a conduit in direct fluid communication between the first separation section and the oligomerization reactor, for recycling the at least a portion of second stream of C2-C6 olefins from the first separation section to the oligomerization reactor;
• installing a conduit in direct fluid communication between the first separation section and the dewaxing reactor, which is arranged downstream, for supplying the third stream of C8-C18 olefins and paraffins to the dewaxing reactor, and in which the dewaxing reactor is further arranged to provide a fifth product stream of branched C8-C18 isoparaffins;
• installing a conduit in direct fluid communication between the first separation section and the hydrocracking reactor for supplying the fourth stream of C18-C30+ olefins and paraffins, and in which the hydrocracking reactor is further arranged to provide a sixth product stream of C1-C30 compounds, the C1-C30 compounds comprising branched C8-C18 isoparaffins, linear or branched C8-C30 paraffins, and C1-C7 paraffins;
• installing a conduit in direct or indirect fluid communication between the first separation section and the hydrocracking reactor, the conduit being arranged for recycling the at least a portion of sixth product stream to the first separation section;
• optionally, installing a second separation section and in direct fluid communication with the hydrocracking reactor, in which the second separation section is arranged to receive the sixth product stream of C1-C30 compounds from the hydrocracking reactor and provide a tenth product stream of the linear or branched C8-C30 paraffins, as the at least a portion of the sixth product stream and which is recycled to the first separation section in the conduit, and in which the conduit is in indirect fluid communication between the first separation section and the hydrocracking reactor via the second separation section;
• the second separation section further arranged to provide a nineth stream of light end compounds comprising the C1-C7 paraffins;
• installing a conduit in direct fluid communication between the dewaxing reactor and the separation section arranged downstream at least the dewaxing reactor for supplying the fifth product stream of branched C8-C18 isoparaffins to the separation section;
• the separation section is further arranged to provide:
• an eighth stream of light end compounds;
• and a seventh 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 0.05, 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 compounds, optionally at least a portion of the nineth stream of light end compounds;
• 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 hydrocracking reactor.