Waste treatment system for PTA and PET manufacturing plants

Abstract

The present invention provides a method for treating the wastes of polyester-manufacturing processes. The method of the invention comprises combining the fuel with a first waste byproduct stream to form a combined fuel and first waste byproduct stream mixture that is combusted in a furnace. The present invention also provides certain useful variations of this method in which one or more of the following steps are performed: a second waste byproduct stream is introduced and treated in a regenerative thermal oxidizer, a third waste byproduct stream is introduced and treated in a waste water treatment plant, or a fourth waste byproduct stream is introduced and treated in a fluid bed incinerator. The present invention also provides an apparatus that executes the methods of the invention.

1 . A method of treating waste in a polyester-manufacturing plant, the polyester-manufacturing plant producing one or more waste byproduct streams and having at least one heat source utilizing a fuel as a combustion source, the method comprising: 
 combining the fuel with a first waste byproduct stream to form a combined fuel and first waste byproduct mixture; and    combusting the combined fuel and first waste byproduct mixture in the at least one heat source; and    wherein the second waste byproduct stream is a liquid waste stream which is vaporized before the second waste byproduct stream is introduced into the regenerative thermal oxidizer.    
   
   
       2 . The method of  claim 1  wherein the at least one heat source is a heat transfer medium furnace in which a liquid is circulated in a coil that is exposed to an open flame and then further circulated to heat exchange devices which transfer heat to polymer forming reactors, the open flame being formed by the combustion of the fuel and the one or more waste byproduct steams.  
   
   
       3 . The method of  claim 2  wherein the coil is heated to a temperature of greater than about 300° C.  
   
   
       4 . The method of  claim 2  wherein the fuel comprising a component selected from the group consisting of natural gas, fuel oil, or combinations thereof.  
   
   
       5 . The method of  claim 1  wherein the first waste byproduct stream comprises an aqueous waste stream which includes an organic compound.  
   
   
       6 . The method of  claim 5  wherein the combustible organic compound is selected from the group consisting of ethylene glycol, acetic acid, acid aldehydes, and combinations thereof.  
   
   
       7 . The method of  claim 1  wherein the polyester-manufacturing plant is a PET or PTA forming plant.  
   
   
       8 . The method of  claim 1  wherein the first waste byproduct stream comprises solid organic components, the solid organic components being sufficiently combustible to be burned in the at least one heat source.  
   
   
       9 . The method of  claim 1  wherein the polyester-manufacturing plant comprises one or more reactors in which polycondensation is utilized to form a polyester.  
   
   
       10 . The method of  claim 1  further comprising introducing a second waste byproduct stream into a regenerative thermal oxidizer.  
   
   
       11 . The method of  claim 10  wherein the second waste byproduct stream comprises a significant amount of non-condensble compounds.  
   
   
       12 . The method of  claim 11  wherein the second waste byproduct stream comprises an inert gas and a volatile organic compound.  
   
   
       13 . The method of  claim 12  wherein the volatile organic compound is selected from the group consisting of acetic acid, methyl acetate, and combinations thereof.  
   
   
       14 . The method of  claim 10  wherein the second waste byproduct stream is a liquid waste stream which is vaporized before the second waste byproduct stream is introduced into the regenerative thermal oxidizer.  
   
   
       15 . The method of  claim 10  further comprising introducing a third waste byproduct stream into a waste water treatment plant.  
   
   
       16 . The method of  claim 15  further comprising introducing a fourth waste byproduct stream into a fluid bed incinerator.  
   
   
       17 . The method of  claim 16  wherein the fourth waste byproduct stream comprises solid organic components, the solid organic components being sufficiently combustible to be burned in the at least one heat source.  
   
   
       18 . The method of  claim 17  wherein the fourth waste byproduct stream comprise the take off gas from a distillation tower.  
   
   
       19 . The method of  claim 18  wherein the fourth waste byproduct stream comprises an aqueous waste stream which includes a volatile organic compound.  
   
   
       20 . The method of  claim 19  wherein the combustible organic compound is selected from the group consisting of ethylene glycol, acetic acid, acid aldehydes, and combinations thereof.  
   
   
       21 . A method of treating waste in a polyester-manufacturing plant, the polyester forming plant producing one or more waste byproduct streams and having at least one heat source utilizing a fuel as a combustion source, the method comprising: 
 combining the fuel with a first waste byproduct stream such that at least a portion of the waste byproduct stream is at least partially combusted with the fuel;    introducing a second waste byproduct stream into a regenerative thermal oxidizer; and    introducing a third waste byproduct stream into a fluid bed incinerator; and    wherein the second waste byproduct stream is a liquid waste stream which is vaporized before the second waste byproduct stream is introduced into the regenerative thermal oxidizer.    
   
   
       22 . The method of  claim 21  wherein the at least one heat source is a heat transfer medium furnace in which a liquid is circulated in a coil that is exposed to an open flame and then further circulated to heat exchange devices which transfer heat to polymer forming reactors, the open flame being formed by the combustion of the fuel and the one or more waste byproduct steams.  
   
   
       23 . The method of  claim 21  wherein the second waste byproduct stream comprises a significant amount of non-condensible compounds.  
   
   
       24 . The method of  claim 21  wherein the second waste byproduct stream comprises an inert gas and a volatile organic compound.  
   
   
       25 . The method of  claim 24  wherein the volatile organic compound is selected from the group consisting of acetic acid, methyl acetate, and combinations thereof.  
   
   
       26 . The method of  claim 21  wherein the second waste byproduct stream is a liquid waste stream which is vaporized before the second waste byproduct stream is introduced into the regenerative thermal oxidizer.  
   
   
       27 . The method of  claim 26  wherein the third waste byproduct stream comprises solid organic components, the solid organic components being sufficiently combustible to be burned in the at least one heat source.  
   
   
       28 . The method of  claim 26  wherein the third waste byproduct stream comprise the take off gas from a distillation tower.  
   
   
       29 . The method of  claim 28  wherein the third waste byproduct stream comprises an aqueous waste stream which includes a volatile organic compound.  
   
   
       30 . The method of  claim 29  wherein the combustible organic compound is selected from the group consisting of ethylene glycol, acetic acid, acid aldehydes, and combinations thereof.