Method of vapor phase polymerization, vapor phase polymerizer and blower

Abstract

A blower 100 for recycling a powder containing gas or for conducting a cyclone treatment thereof, which comprises a casing of blower body 108 having therein a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side, the above slide or rotational slide part being provided with a noncontacted gas leakproof seal part 166 at a clearance ranging from 0.7 to 2.5 mm. A vapor phase polymerization method is provided which is free from the problem that recycling gas such as unreacted gaseous olefin having been discharged from a fluidized bed reactor is formed into a stringy melt polymer or combined into powder to thereby clog a gas recycling pipe or is entrained to a gas recycling pipe or a distributor plate of a polymerizer to thereby cause clogging. Also, a vapor phase polymerizer suitably employed in the above method of vapor phase polymerization and blowers suitably employed in the vapor phase polymerization method and vapor phase polymerizer are provided.

What is claimed is:  
     
         1 . A method of vapor phase polymerization, which comprises blowing a gaseous monomer from a bottom of a fluidized bed reactor through a distributor plate into the fluidized bed reactor by means of a blower while feeding a solid catalyst for polymerization into the fluidized bed reactor to thereby form a fluidized bed in the fluidized bed reactor and carrying out a vapor phase polymerization reaction in the fluidized bed to thereby produce a polymer or copolymer, wherein the blower has a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side in a blower body casing, said slide or rotational slide part being provided with a noncontacted gas leakproof seal part at a clearance ranging from 0.7 to 2.5 mm.  
     
     
         2 . The method as claimed in  claim 1 , wherein the gas leakproof seal part is provided at a clearance ranging from 0.9 to 1.2 mm.  
     
     
         3 . The method as claimed in  claim 1  or  2 , wherein the solid catalyst for polymerization is a solid catalyst for olefin polymerization, the gaseous monomer is a gaseous olefin monomer and an olefin polymer or copolymer is obtained by the vapor phase polymerization reaction in the fluidized bed.  
     
     
         4 . The method as claimed in any of  claims 1  to  3 , wherein unreacted gaseous monomer is discharged from the fluidized bed reactor and is caused to pass through a gas recycling path having a heat exchanger disposed upstream thereof and having a blower disposed downstream thereof so that the heat exchanged gaseous monomer is blown into the fluidized bed reactor.  
     
     
         5 . The method as claimed in  claim 4 , wherein the gaseous monomer fed by the blower comprises a component which condenses at a temperature ranging from 50° C. lower than a temperature at which the vapor phase polymerization reaction is conducted in the fluidized bed to the temperature of vapor phase polymerization reaction.  
     
     
         6 . The method as claimed in  claim 5 , wherein the gaseous monomer is fed into the fluidized bed at a temperature which is lower than the condensation temperature of the condensing component.  
     
     
         7 . A vapor phase polymerizer comprising a fluidized bed reactor in which a gaseous monomer is blown from a bottom thereof through a distributor plate while a solid catalyst for polymerization is fed thereinto to thereby form a fluidized bed so that a vapor phase polymerization reaction is carried out in the fluidized bed to thereby produce a polymer or copolymer, 
 said vapor phase polymerizer further comprising: 
 a gas discharge port adapted to discharge unreacted monomer gas, disposed at a top of the fluidized bed reactor,  
 a gas recycling path connected to the gas discharge port and extending to a bottom of the fluidized bed reactor,  
 a heat exchanger arranged upstream of the gas recycling path, and  
 a gas circulator arranged downstream of the gas recycling path.  
   
     
     
         8 . The vapor phase polymerizer as claimed in  claim 7 , wherein the heat exchanger is a shell and tube heat exchanger in which tubes through which gas is passed for heat exchange are welded to tube plates provided for fixing the tubes to a shell of the heat exchanger, each welding portion being so formed that the tube has at its opening a front end positioned inside a tube plate surface and has at its opening a front end rounded.  
     
     
         9 . A blower for recycling a powder containing gas or for conducting a cyclone treatment thereof, which comprises: 
 a blower body casing having therein a slide or rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side, said slide or rotational slide part being provided with a noncontacted gas leakproof seal part at a clearance ranging from 0.7 to 2.5 mm.    
     
     
         10 . The blower as claimed in  claim 9 , wherein the gas leakproof seal part is provided at a clearance ranging from 0.9 to 1.2 mm.  
     
     
         11 . A turboblower for recycling a powder containing gas or for conducting a cyclone treatment thereof, which comprises: 
 a blower body casing having therein a rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side, said rotational slide part being provided with a laby-rinth seal as a noncontacted gas leakproof seal part at a clearance ranging from 0.7 to 2.5 mm.    
     
     
         12 . The turboblower as claimed in  claim 11 , wherein the labyrinth seal is provided at a clearance ranging from 0.9 to 1.2 mm.  
     
     
         13 . The turboblower as claimed in  claim 11  or  12 , which has an impeller connected to a principal shaft in the blower body casing and wherein the laby-rinth seal is arranged at a rotational slide part between the impeller and a suction port.  
     
     
         14 . A Roots blower for recycling a powder containing gas or for conducting a cyclone treatment thereof, which comprises 
 rotors, and    a blower body casing having therein a rotational slide part between its discharge side as a high pressure side and its suction side as a low pressure side, said rotational slide part being provided with a noncontacted gas leakproof seal part,    said gas leakproof seal part being composed of a clearance between a periphery of each rotor and an inner wall of the casing and a clearance between the rotors,    each of the clearances ranging from 0.7 to 2.5 mm.    
     
     
         15 . The Roots blower as claimed in  claim 14 , wherein each of the clearances ranges from 0.9 to 1.2 mm.  
     
     
         16 . The vapor phase polymerizer as claimed in  claim 7  or  8 , wherein the gas circulator is the blower of any of  claims 9  to  15 .