Method for preparing ethylene propylene
A device for mixing at least two granular materials has a first lifting tube used for loading first particles and a second lifting tube surrounding and coaxial to the first lifting tube and used for loading second particles. The upper part of said first lifting tube extends beyond the top of said second lifting tube, and at least part of the upper part of the first lifting tube and at least part of the upper part of the second lift tube are located inside a fast bed precipitator, allowing the first and second particles to be transported by means of the first and second lifting tubes to the interior of said fast bed precipitator and mixed.
1 . A process for producing ethylene-propylene in a reaction system comprising a first reactor and a second reactor, the first reactor comprising a fast bed reactor, a fast bed settler, and a first riser tube, the second reactor comprising a second riser tube and a riser settler, comprising:
a) in the first reactor, feeding a methanol feedstock and a catalyst into the fast bed reactor, obtaining a reaction product I and a first particulate catalyst produced by partial inactivation of the catalyst, which exits from the fast bed reactor and enters the fast bed settler;
b) in the second reactor, feeding a first feedstock and a regenerated catalyst into the second riser tube, producing a first mixture comprising a reaction product II and a second particulate catalyst, wherein the first mixture exits the second riser tube and enters the riser settler to separate a reaction product II from the second particulate catalyst, separating the second particulate catalyst into a first part of the second particulate catalyst and a second part of the second particulate catalyst;
c) in the first reactor, feeding the second part of the second particulate catalyst into the first riser tube, producing a second mixture comprising a third particulate catalyst, wherein the second mixture exits the first riser tube and enters the fast bed settler; and
d) obtaining a mixed catalyst comprising the first particulate catalyst the third particulate catalyst in the fast bed settler, and feeding a first part of the mixed catalyst and the first part of the second particulate catalyst into a regenerator for regeneration to obtain the regenerated catalyst,
wherein the first feedstock is selected from an oxygenate feedstock, a light hydrocarbon feedstock, and a mixture thereof, the oxygenate feedstock comprises water and oxygenates, the oxygenates are present in an amount of from 5 to 60 wt % of the oxygenate feedstock, and the light hydrocarbon feedstock comprises a C4-C6 non-aromatic hydrocarbon mixture; and
wherein the fast bed reactor, the fast bed settler and the first riser tube are coaxially arranged, and the first riser tube has a riser outlet, and the fast bed reactor has a fast bed outlet, and both the riser outlet and the fast bed outlet are disposed in the fast bed settler.
2 . The process according to claim 1 , wherein in step c), a second feedstock is fed into the first riser tube in the first reactor together with the second part of the second particulate catalyst, and
the second mixture further comprises a reaction product III,
wherein the second feedstock is the same or different from the first feedstock, and is independently selected from the oxygenate feedstock, the light hydrocarbon feedstock, and the mixture thereof.
3 . The process according to claim 2 , wherein the first feedstock to the second reactor is the light hydrocarbon feedstock, and the second feedstock to the first reactor is the oxygenate feedstock.
4 . The process according to claim 2 , wherein the first feedstock to the second reactor comprises the oxygenate feedstock and the light hydrocarbon feedstock, and the second feedstock to the first reactor comprises the oxygenate feedstock and the light hydrocarbon feedstock.
5 . The process according to claim 2 , wherein the first feedstock to the second reactor is the oxygenate feedstock, and the second feedstock to the first reactor is the light hydrocarbon feedstock.
6 . The process according to claim 2 , wherein Rw is a weight ratio of the second particulate catalyst or the mixture of the reaction product III and the third particulate catalyst to the first particulate catalyst, and has a value of 0.01<Rw≤0.5.
7 . The process according to claim 1 , wherein the first reactor further comprises an outside exchanger disposed in the fast settler and having an inlet connected to an outlet of the fast bed reactor, the process further comprising feeding a second part of the mixed catalyst to the fast bed reactor, and feeding a third part of the mixed catalyst into the outside heat-exchanger; and wherein a weight ratio of the first part, the second part, and the third part of the mixed catalyst is (0.5-1):(5-7):(2-4.5).
8 . The process according to claim 1 , wherein a weight ratio of the first part to the second part of the second particulate catalyst is (1-3):(7-9).
9 . The process according to claim 1 , further comprising feeding the first part of the mixed catalyst and the first part of second particulate catalyst into a stripper for stripping; and feeding the stripped catalyst from the stripper into the regenerator for regeneration.
10 . The process according to claim 2 , further comprising combining the reaction product I, the reaction product II and the reaction product III and then feeding the combination into a separation unit to obtain a product rich in ethylene and propylene, a C4-C6 non-aromatic hydrocarbon mixture, and an aqueous phase,
wherein the oxygenates in the oxygenate feedstock contain methanol and one or more selected from ethanol, propanol, butanol, acetaldehyde, propionaldehyde, butyraldehyde, acetone, butanone, formic acid, acetic acid, and propionic acid.
11 . The process according to claim 1 , wherein,
the fast bed reactor is operated at a catalyst temperature of 450 to 500° C., a gas linear velocity of 0.8 to 3 m/s, a reaction gauge pressure of 0.01 to 0.5 MPa, and a catalyst density of 50 to 250 kg/m 3 ; and/or
the second reactor is operated at a temperature of the catalyst of 580-650° C., a gas linear velocity of 1.1-3 m/s, and a catalyst density of 50-100 kg/m 3 ; and/or
the first riser tube is operated at a temperature of the catalyst of 530-580° C., a gas linear velocity of 3-5 m/s, and a catalyst density of 20-80 kg/m 3 .
12 . The process according to claim 1 , wherein,
the catalyst is SAPO-34 molecular sieve catalyst; and/or
the regenerated catalyst has a carbon content of less than 0.1% by weight, based on the total weight of the catalyst.
13 . The process according to claim 1 , wherein the first feedstock to the second reactor comprises the oxygenate feedstock and the light hydrocarbon feedstock.