US 4,855,524 A · Process for combining the operation of oligomerization reactors containing a zeolite oligomerization catalyst

Abstract

A process is disclosed for combining the operation of (i) a primary reactor (referred to as a "MOG" reactor), in which an olefin-containing light gas or light naphtha is oligomerized to gasoline range hydrocarbons, and, (ii) a high pressure secondary reactor (referred to as a "MODL" reactor), to make distillate or lubes, using the effluent (primary effluent) from the MOG reactor as feed for the MODL reactor. In the distillate mode, the primary effluent is tailored so as to be substantially free (less than 3 mol %) of C.sub.10.sup.+ components. Because the C.sub.10.sup.+ "make" from the MOG reactor is spared passage through the MODL reactor, conversion of the C.sub.10.sup.+ components typically experienced due to cracking and oligomerization in the MODL is avoided. Because the C.sub.4.sup.- light components which are highly paraffinic, are separated from the primary effluent in a debutanizer to provide a mainly C.sub.5 -C.sub.9 stream, conversion of olefins to distillate in the MODL reactor is enhanced relative to using a feed, not tailored as described, to the MODL reactor. The yield of desired C.sub.10.sup.+ product is surprisingly high. In addition, the throughput to the MODL reactor is substantially reduced. Various embodiments of the process are disclosed to provide economic processes to meet the challenge of oligomerizing lower olefins to distillate and lubes.

Claims30

Dependent claims

In a catalytic process comprising multistage reaction zones for oligomerizing olefin-containing FCC gas, light gas having from 3 to 5 carbon atoms (C.sub.3 -C.sub.5) or light naphtha (C.sub.5 -C.sub.7) feedstock, into a C.sub.10.sup.+ aliphatic hydrocarbon product, including maintaining a primary reaction zone containing zeolite catalyst particles in a low severity reactor bed;

passing said feedstock upwardly through said primary reaction zone in a single pass at sufficiently high pressure and temperature to provide reaction severity conditions sufficient to oilgomerize lower alkenes to intermediate range olefins mainly in the C.sub.5 -C.sub.9 range;
withdrawing from said primary reaction zone a primary effluent containing olefins with a major amount by weight of C.sub.5.sup.+ olefinic hydrocarbons, and, a minor amount of C.sub.4.sup.- olefinic hydrocarbons;
and, further oligomerizing said C.sub.5.sup.+ hydrocarbons in a secondary reaction zone by contacting with a bed of medium pore shape selective acid oligomerization catalyst, further to upgrade them to said C.sub.10.sup.+ product;
the improvement comprising,
(a) separating C.sub.4.sup.- substantially light gas components from said primary effluent so as to provide a predominantly olefinic C.sub.5.sup.+ intermediate stream subtantially free of said C.sub.4.sup.- components and comprising at least 1 part by weight of distillate per 10 parts of gasoline;
(b) contacting said intermediate stream with said oligomerization catalyst in said secondary reaction zone under oligomerization conditions to produce a predominantly C.sub.10.sup.+ effluent, and,
(c) recovering said C.sub.10.sup.+ aliphatic product.

4 more elements

A multistage catalytic process for converting a FCC gas, light gas or light naphtha feedstock containing at least 10% by weight olefins, to a product rich in C.sub.10.sup.+ aliphatic hydrocarbons, comprising,

(a) maintaining a primary reaction zone containing a bed of zeolite catalyst particles at oligomerization pressure and temperature for said olefins,
(b) passing hot feedstock vapor upwardly through said bed in a single pass at reaction severity conditions sufficient to upgrade said olefins to intermediate range olefins mainly in the C.sub.5 -C.sub.9 range, with a per pass conversion of at least 70%, and a pentane to pentane ratio (C.sub.5 :C.sub.5.sup.=) of less than 0.2:1,
(c) recovering from said primary reaction zone a primary effluent containing olefins with a major amount of C.sub.5.sup.+ olefinic hydrocarbons including at least 1 part by weight of distillate per 10 parts of gasoline, less than about 3 mol % aromatics, and a minor amount of C.sub.4.sup.- olefinic hydrocarbons,
(d) removing substantially all said C.sub.4.sup.- hydrocarbons from said primary effluent to provide a substantially olefinic C.sub.5.sup.+ intermediate stream,
(e) further oligomerizing said intermediate stream in a secondary reaction zone by contacting said intermediate stream with a medium pore shape selective acid oligomerization catalyst under oligomerization conditions in the absence of added hydrogen to produce a predominantly C.sub.10.sup.+ secondary effluent, at a per pass conversion of at least 50% of olefins therein, and,
(f) recovering a C.sub.10.sup.+ aliphatic product stream from said secondary effluent.

3 more elements

A multistage catalytic process for converting lower olefinic feedstock to a C.sub.10.sup.+ distillate product, comprising,

(a) contacting C.sub.3 -C.sub.4 -rich feedstock having an alkene content of at least 10% by weight, at elevated temperature in a continuous primary reaction zone with a first shape selective medium pore zeolite oligomerization catalyst to convert at least 80% of propene to C.sub.5.sup.+ olefinic hydrocarbons under reaction severity conditions sufficient to produce pentane and pentene in a weight ratio of about 0.05 to 2:1, said first shape selective catalyst having an average equilibrated alpha in the range from about 0.1 to about 20,
(b) cooling effluent from said primary reaction zone to condense at least a portion thereof and flowing it to a debutanizing zone in which gaseous C.sub.4.sup.- components are separated from C.sub.5.sup.+ components,
(c) flowing an intermediate stream of said C.sub.5.sup.+ components to a fractionation zone located upstream of a secondary reaction zone and separating substantially C.sub.5 -C.sub.9 gasoline from C.sub.10.sup.+ distillate so as to recover a substantially C.sub.10.sup.+ -free gasoline stream,
(d) contacting said substantially C.sub.10.sup.+ -free gasoline stream with a second shape selective medium pore zeolite oligomerization catalyst having an acid cracking activity of at least 5, maintained in said secondary reaction zone under higher pressure than said primary reaction zone, to produce a secondary effluent in which at least 50% of said olefins in said intermediate stream are converted per pass to C.sub.10.sup.+ components,
(e) at least partially condensing said secondary effluent to condense substantially all said C.sub.10.sup.+ components in a gas-liquid separation zone from which gaseous C.sub.9.sup.- components are recycled to said primary reaction zone,
(f) flowing said C.sub.10.sup.+ components from said second gas-liquid separation zone to said fractionation zone for separating gasoline and distillate, and,
(g) recovering said C.sub.10.sup.+ distillate product.

4 more elements

A multistage catalytic process for converting lower olefinic feedstock to a C.sub.10.sup.+ distillate product, comprising,

(a) contacting C.sub.3 -C.sub.4 -rich feedstock having an alkene content of at least 10% by weight, at elevated temperature in a continuous primary reaction zone with a first shape selective medium pore zeolite oligomerization catalyst to convert at least 80% of propene to C.sub.5.sup.+ olefinic hydrocarbons under reaction severity conditions sufficient to produce pentane and pentene in a weight ratio of about 0.05:1 to 2:1, said first shape selective catalyst having an average equilibrated alpha in the range from about 1 to about 20,
(b) cooling effluent from said primary reaction zone to condense at least a portion of said hydrocarbons in a first gas-liquid separation zone in which gaseous C.sub.9.sup.- components are separated from a "wild" C.sub.10.sup.+ liquid stream,
(c) flowing said C.sub.9.sup.- components to a first fractionation zone and separating a substantially C.sub.5 -C.sub.9 gasoline from light C.sub.4.sup.- hydrocarbons so as to recover a substantially C.sub.10.sup.+ -free gasoline stream,
(d) contacting said substantially C.sub.10.sup.+ -free gasoline stream with a second shape selective medium pore zeolite oligomerization catalyst having an acid cracking activity of at least 5, maintained in a higher pressure secondary reaction zone than said primary reaction zone, to produce a secondary effluent from which is recovered a higher net yield of C.sub.10.sup.+ components that net yield of gasoline,
(e) cooling said secondary effluent to condense substantially all said C.sub.10.sup.+ components in a second gas-liquid separation zone from which gaseous C.sub.9.sup.- components are recycled to said primary reaction zone,
(f) flowing said C.sub.10.sup.+ components from said second gas-liquid separation zone to a second fractionation zone for separating gasoline and distillate, said second fractionation zone being located downstream of said secondary reaction zone,
(g) flowing from 0 to 100% of said wild liquid stream to said second fractionation zone for separating gasoline and distillate, second fractionation zone, and,
(h) recovering said C.sub.10.sup.+ distillate product.

5 more elements

Dependencies are inferred from the claim text.

Process for combining the operation of oligomerization reactors containing a zeolite oligomerization catalyst

Life of this patent

Process for combining the operation of oligomerization reactors containing a zeolite oligomerization catalyst

Life of this patent

Abstract

Claims30