Device and method for preparing aromatic hydrocarbons from naphtha

Abstract

The application discloses a device and method for preparing aromatic hydrocarbons from naphtha, and the device comprises a fluidized bed reactor and a riser reactor; the fluidized bed reactor is used for introducing a naphtha raw material to make contact with a catalyst from the riser reactor and react to generate a BTX-containing product gas stream and a spent catalyst, the product gas stream is subjected to gas-solid separation, the product gas stream after separation is sent to a downstream working section, and unconverted naphtha after separation returns to the fluidized bed reactor as a raw material; and a part of low-carbon alkanes after separation return to the riser reactor as raw materials and are further converted into aromatic hydrocarbons and other components. According to the application, by connecting a high-temperature riser reactor and a relatively low-temperature fluidized bed reactor in series, a yield of low-carbon alkane is reduced and a yield of aromatic hydrocarbons is increased; and linear-chain and branched-chain aliphatic hydrocarbons can be efficiently converted into the aromatic hydrocarbons in a highly selective mode, and a content of p-xylene in a xylene mixture is greater than 50 wt %.

1 . A device for preparing aromatic hydrocarbons from naphtha, wherein the device comprises a fluidized bed reactor and a riser reactor; wherein, an outlet of the riser reactor is connected to the fluidized bed reactor; and
 the fluidized bed reactor is used for introducing a naphtha raw material to make contact with a catalyst from the riser reactor and react to generate a BTX-containing product gas stream and a spent catalyst, the product gas stream is subjected to gas-solid separation, the product gas stream after separation is sent to a downstream working section, and unconverted naphtha after separation returns to the fluidized bed reactor as a raw material; and a part of low-carbon alkanes after separation return to the riser reactor as raw materials.   
     
     
         2 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein the riser reactor is used for introducing a riser reactor raw material and a catalyst to react to generate aromatic hydrocarbons, and a stream containing unreacted riser reactor raw material, aromatic hydrocarbons and the catalyst enters the fluidized bed reactor through the outlet of the riser reactor;
 preferably, wherein the riser reactor raw material comprises water vapor and the low-carbon alkanes separated from the product gas stream;   preferably, wherein a water vapor content in the riser reactor raw material is 0 wt % to 50 wt %.   
     
     
         3 - 4 . (canceled) 
     
     
         5 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein an inlet of the riser reactor is connected with a fluidized bed regenerator, and the catalyst introduced into the riser reactor is a regenerated catalyst generated by the fluidized bed regenerator;
 preferably, wherein the fluidized bed regenerator sequentially passes through a regenerator stripper and a regenerated slide valve to be connected to the inlet of the riser reactor through a pipeline;   more preferably, wherein an inlet of the regenerator stripper extends into a regenerator shell of the fluidized bed regenerator and is located above a regenerator distributor.   
     
     
         6 - 7 . (canceled) 
     
     
         8 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein the fluidized bed reactor comprises a reactor shell, an area enclosed by the reactor shell is divided into a first gas-solid separation zone and a reaction zone from top to bottom, and a gas-solid separation device and a reactor gas collection chamber are provided in the first gas-solid separation zone; the reactor gas collection chamber is located on an inner top portion of the reactor shell, an inlet of the reactor gas collection chamber is communicated with a gas outlet of a reactor gas-solid separation device, and an outlet of the reactor gas collection chamber is communicated with a product gas conveying pipe; and a reactor distributor is provided on a lower portion of the reaction zone for introducing the naphtha raw material;
 preferably, wherein the reactor gas-solid separation device is one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators comprises a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.   
     
     
         9 . (canceled) 
     
     
         10 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein the device further comprises a fluidized bed regenerator connected with the fluidized bed reactor, the fluidized bed regenerator is used for introducing regeneration gas to convert the spent catalyst into a regenerated catalyst. 
     
     
         11 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein the fluidized bed reactor sequentially passes through a reactor stripper, a spent slide valve and a spent agent conveying pipe to be connected with a fluidized bed regenerator; wherein, an inlet of the reactor stripper extends into a fluidized bed reactor shell and is located below a catalyst outlet end of a reactor gas-solid separation device. 
     
     
         12 . The device for preparing aromatic hydrocarbons from naphtha according to  claim 1 , wherein the fluidized bed regenerator comprises a regenerator shell, and an area enclosed by the regenerator shell is divided into a second gas-solid separation zone and a regeneration zone from top to bottom; a regenerator gas-solid separation device and a regenerator gas collection chamber are provided in the second gas-solid separation zone; the regenerator gas collection chamber is located on an inner top portion of the regenerator shell, and a flue gas conveying pipe is provided on the regenerator gas collection chamber; a gas outlet of the regenerator gas-solid separation device is communicated with the regenerator gas collection chamber; and a regenerator distributor is arranged on an inner lower portion of the regeneration zone for introducing regeneration gas;
 preferably, wherein the regenerator gas-solid separation device is one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators comprises a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.   
     
     
         13 . (canceled) 
     
     
         14 . A method for preparing aromatic hydrocarbons from naphtha, wherein the method comprises: preparing aromatic hydrocarbons by using the device for preparing aromatic hydrocarbons from naphtha according to  claim 1  and a catalyst. 
     
     
         15 . The method for preparing aromatic hydrocarbons from naphtha according to  claim 14 , wherein the catalyst is a metal molecular sieve bifunctional catalyst;
 preferably, wherein the metal molecular sieve bifunctional catalyst is a metal modified HZSM-5 zeolite molecular sieve;   metal for the metal modification is selected from at least one of La, Zn, Ga, Fe, Mo and Cr; and   a method for the metal modification comprises: placing the HZSM-5 zeolite molecular sieve in a metal salt solution, soaking, drying and roasting to obtain the metal modified HZSM-5 zeolite molecular sieve.   
     
     
         16 . (canceled) 
     
     
         17 . The method for preparing aromatic hydrocarbons from naphtha according to  claim 14 , wherein the method comprises: allowing the naphtha to enter a reaction zone of the fluidized bed reactor through a reactor distributor to make contact with the catalyst from the riser reactor to generate a product gas stream containing BTX, a low-carbon olefin, hydrogen, a low-carbon alkane, combustible gas, a heavy aromatic hydrocarbon and unconverted naphtha, and allowing the catalyst to coke and converted into the spent catalyst at the same time; and
 allowing the product gas stream to enter a reactor gas-solid separation device to remove a spent catalyst contained in the product gas stream, then enter a reactor gas collection chamber, and enter the a downstream working section through a product gas conveying pipe;   preferably, wherein the method further comprises: allowing the unconverted naphtha after separation to return to the fluidized bed reactor as a raw material;   preferably, wherein the method further comprises: allowing a part of low-carbon alkanes after separation to return to the riser reactor as raw materials;   preferably, wherein the low-carbon olefin refers to ethylene and propylene;   the low-carbon alkane refers to ethane and propane;   the combustible gas comprises methane and CO; and   the heavy aromatic hydrocarbon refers to an aromatic hydrocarbon with a number of carbon atoms in a molecule greater than or equal to 9;   preferably, wherein the naphtha is selected from at least one of direct coal liquefaction naphtha, indirect coal liquefaction naphtha, straight-run naphtha and hydrocracking naphtha;   more preferably, wherein the naphtha also contains the unconverted naphtha separated from the product gas stream, and the unconverted naphtha comprises main components of C 4 -C 12  linear-chain and branched-chain aliphatic hydrocarbons and a naphthenic hydrocarbon;   preferably, wherein a carbon content in the spent catalyst is 1.0 wt % to 3.0 wt %;   preferably, wherein process conditions of the reaction zone are: an apparent linear velocity of gas of 0.5 m/s to 2.0 m/s, a reaction temperature of 500° C. to 650° C., a reaction pressure of 100 kPa to 500 kPa, and a bed density of 150 kg/m 3  to 700 kg/m 3 ;   preferably, wherein the method further comprises: introducing a riser reactor raw material and the catalyst into the riser reactor to react to generate aromatic hydrocarbons; and   allowing a stream containing unreacted riser reactor raw material, aromatic hydrocarbons and the catalyst to enter the fluidized bed reactor from the outlet of the riser reactor;   more preferably, wherein the catalyst is a regenerated catalyst from a fluidized bed regenerator;   even more preferably, wherein the regenerated catalyst sequentially passes through a regenerator stripper and a regenerated slide valve to enter the riser reactor;   even more preferably, wherein a carbon content in the regenerated catalyst is less than or equal to 0.5 wt %;   more preferably, wherein the riser reactor raw material comprises water vapor and the low-carbon alkane separated from the product gas stream.;   more preferably, wherein a water vapor content in the riser reactor raw material is 0 wt % to 50 wt %;   more preferably, wherein process conditions of the riser reactor are: an apparent linear velocity of gas of 3.0 m/s to 10.0 m/s, a temperature of 580° C. to 700° C., a pressure of 100 kPa to 500 kPa, and a bed density of 50 kg/m 3  to 150 kg/m 3 ;   preferably, wherein the method further comprises: allowing the spent catalyst to enter a reactor stripper from an opening end of an inlet pipe of the reactor stripper, and after the spent catalyst is stripped by the reactor stripper, allowing the spent catalyst to enter a downstream area through a spent slide valve and a spent agent conveying pipe;   more preferably, wherein the downstream area is the fluidized bed regenerator;   more preferably, wherein the method further comprises: introducing regeneration gas into a regeneration zone of the fluidized bed regenerator through a regenerator distributor to make contact with the spent catalyst from the fluidized bed reactor, allowing coke on the spent catalyst to react with the regeneration gas to generate a flue gas, and converting the spent catalyst into the regenerated catalyst at the same time;   even more preferably, wherein the spent catalyst sequentially passes through the reactor stripper, the spent slide valve and the spent agent conveying pipe to enter the fluidized bed regenerator, and makes contact and reacts with the regeneration gas to obtain the flue gas and the regenerated catalyst; and   the flue gas enters a regenerator gas-solid separation device to remove a regenerated catalyst contained in the flue gas, then enters a regenerator gas collection chamber, and enters the downstream working section through the flue gas conveying pipe;   even more preferably, wherein the regeneration gas is selected from at least one of oxygen, air and oxygen-enriched air:   even more preferably, wherein process conditions of the regeneration zone are: an apparent linear velocity of gas of 0.5 m/s to 2.0 m/s. a regeneration temperature of 600° C. to 750° C. a regeneration pressure of 100 kPa to 500 kPa, and a bed density of 150 kg/m 3  to 700 kg/m 3 .   
     
     
         18 - 27 . (canceled)