Methods and systems for particulate matter removal from a process exhaust gas stream

Abstract

Disclosed herein are systems and methods for reducing the particulate matter content of an exhaust gas from a carbon black process.

We claim: 
     
         1 . A method of reducing particulate matter from an exhaust gas from a process for the production of carbon black, comprising:
 producing carbon black and the exhaust gas in the process for the production of carbon black;   collecting the carbon black, wherein collecting the carbon black comprises filtering to separate the carbon black from the exhaust gas, thereby producing a separated exhaust gas;   combusting the separated exhaust gas to thereby produce a combusted exhaust gas comprising particulate matter; and   catalytically oxidizing at least a portion of the particulate matter of the combusted exhaust gas by passing the combusted exhaust gas through a vessel comprising an oxidation catalyst, thereby removing at least a portion of the particulate matter from the combusted exhaust gas to thereby produce an oxidized exhaust gas.   
     
     
         2 . The method of  claim 1 , wherein the combusted exhaust gas is not passed through an electrostatic precipitator. 
     
     
         3 . The method of  claim 1 , wherein the exhaust gas is produced from thermal decomposition of a hydrocarbon or incomplete combustion of a hydrocarbon. 
     
     
         4 . The method of  claim 3 , wherein the hydrocarbon comprises a heavy distillate oil, a heavy residual oil, a vacuum distillate oil, a heavy vacuum oil, a fluidized catalytic cracker distillate oil, a fluidized catalytic cracker residual oil, a distillate oil from coal gasification, a residual oil from coal gasification, a tar oil from coal gasification, a distillate oil from coal distillation, a residual oil from coal distillation, a tar oil from coal distillation, a distillate oil from steam cracking, a residual oil from steam cracking, a tar oil from steam cracking, a distillate oil from polymer reaction distillation processes, a residual oil from polymer reaction distillation processes, a tar oil from polymer reaction distillation processes, a distillate oil from a biological source, a fuel oil from a biological source, a residual oil from a biological source, a distillate oil from a renewable source, a fuel oil from a renewable source, a residual oil from a renewable source, or combinations thereof. 
     
     
         5 . The method of  claim 1 , wherein the exhaust gas comprises from 1 to 5,000 mg/Nm 3  of particulate matter. 
     
     
         6 . The method of  claim 1 , wherein the exhaust gas comprises 30 mg/Nm 3  or less of particulate matter. 
     
     
         7 . The method of  claim 1 , wherein the combusted exhaust gas comprises from 1 to 5,000 mg/Nm 3  of particulate matter. 
     
     
         8 . The method of  claim 1 , wherein the oxidation catalyst is a catalyst capable of catalytically converting SO 2  to SO 3  out of a wet gas stream. 
     
     
         9 . The method of  claim 1 , wherein the oxidation catalyst comprises vanadium, cobalt, molybdenum, manganese, sodium, potassium, cesium, platinum, palladium, iron, or combinations thereof. 
     
     
         10 . The method of  claim 1 , wherein the oxidation catalyst is supported on a thermally stable substrate. 
     
     
         11 . The method of  claim 10 , wherein the thermally stable substrate comprises alumina, silica, chromia, zirconia, tungsten, diatomaceous earth, cordierite, or combinations thereof. 
     
     
         12 . The method of  claim 1 , wherein the oxidation catalyst oxidizes 90 wt. % or more of the particulate matter, based on the total mass of particulate matter present in the combusted exhaust gas before passing the combusted exhaust gas through the vessel comprising the oxidation catalyst. 
     
     
         13 . The method of  claim 1 , wherein the oxidized exhaust gas comprises 30 mg/Nm 3  or less of particulate matter. 
     
     
         14 . The method of  claim 1 , wherein the combusted exhaust gas comprises from 50 to 6,000 ppmv sulfur dioxide. 
     
     
         15 . The method of  claim 1 , wherein the oxidized exhaust gas further comprises a sulfur oxide and the method further comprises treating the oxidized exhaust gas in a wet sulfuric acid process without heating the oxidized exhaust gas to thereby remove at least a portion of the sulfur oxide. 
     
     
         16 . The method of  claim 15 , wherein the sulfur oxide is removed from the oxidized exhaust gas with increased thermal efficiency as compared to a method in which substantially equivalent particulate matter reduction is achieved using an electrostatic precipitator. 
     
     
         17 . The method of  claim 1 , wherein the oxidized exhaust gas comprises from 10 to 50 wt. % water, less than 10 mg/Nm 3  particulate matter, and from 50 ppmv to 10 wt. % sulfur dioxide. 
     
     
         18 . The method of  claim 1 , wherein the oxidation catalyst comprises vanadium, sodium, potassium, cesium, platinum, palladium, or combinations thereof. 
     
     
         19 . The method of  claim 1 , wherein the oxidation catalyst is a wet sulfuric acid (WSA) catalyst. 
     
     
         20 . The method of  claim 1 , wherein the oxidation catalyst is a vanadium oxide comprising one or more of Na, K or Cs supported on a thermally stable substrate. 
     
     
         21 . The method of  claim 1 , wherein the oxidation catalyst is a vanadium oxide comprising Na, K and Cs supported on a thermally stable substrate. 
     
     
         22 . The method of  claim 20 , wherein the thermally stable substrate is diatomaceous earth. 
     
     
         23 . The method of  claim 15 , wherein the vessel is a portion or stage of a wet sulfuric acid process reactor. 
     
     
         24 . The method of  claim 15 , wherein the vessel is an initial portion or stage of a wet sulfuric acid process reactor. 
     
     
         25 . The method of  claim 23 , wherein the oxidation catalyst is a catalyst capable of catalytically converting SO 2  to SO 3  out of a wet gas stream. 
     
     
         26 . The method of  claim 23 , wherein the oxidation catalyst is a wet sulfuric acid (WSA) catalyst. 
     
     
         27 . The method of  claim 23 , wherein the oxidation catalyst comprises vanadium, sodium, potassium, cesium, platinum, palladium, or combinations thereof. 
     
     
         28 . The method of  claim 23 , wherein the oxidation catalyst is a vanadium oxide comprising one or more of Na, K or Cs supported on a thermally stable substrate. 
     
     
         29 . The method of  claim 23 , wherein the oxidation catalyst is a vanadium oxide comprising Na, K and Cs supported on a thermally stable substrate. 
     
     
         30 . The method of  claim 29 , wherein the thermally stable substrate is diatomaceous earth. 
     
     
         31 . The method of  claim 1 , further comprising removing nitrogen oxides from combusted exhaust gas. 
     
     
         32 . The method of  claim 31 , wherein nitrogen oxides are removed from combusted exhaust gas prior to catalytically oxidizing at least a portion of the particulate matter of the combusted exhaust gas. 
     
     
         33 . The method of  claim 31 , wherein the oxidation catalyst is a catalyst capable of catalytically converting SO 2  to SO 3  out of a wet gas stream. 
     
     
         34 . The method of  claim 31 , wherein the oxidation catalyst is a wet sulfuric acid (WSA) catalyst. 
     
     
         35 . The method of  claim 31 , wherein the oxidation catalyst comprises vanadium, sodium, potassium, cesium, platinum, palladium, or combinations thereof. 
     
     
         36 . The method of  claim 31 , wherein the oxidation catalyst is a vanadium oxide comprising one or more of Na, K or Cs supported on a thermally stable substrate. 
     
     
         37 . The method of  claim 31 , wherein the oxidation catalyst is a vanadium oxide comprising Na, K and Cs supported on a thermally stable substrate. 
     
     
         38 . The method of  claim 37 , wherein the thermally stable substrate is diatomaceous earth. 
     
     
         39 . A system for reducing particulate matter in a reduced exhaust gas from a carbon black process module, comprising:
 a combustion device configured to receive the reduced exhaust gas and combust the reduced exhaust gas to produce a combusted exhaust gas comprising particulate matter; and   a particulate removal device configured to receive the combusted exhaust gas and catalytically oxidize at least a portion of the particulate matter from the combusted exhaust gas, wherein the particulate removal device is a vessel comprising an oxidation catalyst.   
     
     
         40 . The system of  claim 39 , wherein the system does not contain an electrostatic precipitator. 
     
     
         41 . The system of  claim 39 , further comprising:
 a wet sulfuric acid process reactor configured to receive combusted exhaust gas for removal of at least a portion of the SO 2  therein.   
     
     
         42 . The system of  claim 39 , wherein the vessel comprising an oxidation catalyst is a portion or stage of the wet sulfuric acid process reactor. 
     
     
         43 . The system of  claim 39 , wherein the vessel comprising an oxidation catalyst is an initial portion or stage of the wet sulfuric acid process reactor. 
     
     
         44 . The system of  claim 42 , wherein:
 the oxidation catalyst is a catalyst capable of catalytically converting SO 2  to SO 3  out of a wet gas stream; or   the oxidation catalyst is a wet sulfuric acid (WSA) catalyst; or   the oxidation catalyst comprises vanadium, sodium, potassium, cesium, platinum, palladium, or combinations thereof; or   the oxidation catalyst is a vanadium oxide comprising one or more of Na, K or Cs supported on a thermally stable substrate; or   the oxidation catalyst is a vanadium oxide comprising Na, K and Cs supported on a thermally stable substrate.   
     
     
         45 . The system of  claim 44 , wherein the thermally stable substrate is diatomaceous earth. 
     
     
         46 . The system of  claim 42 , further comprising:
 a selective catalytic reduction reactor configured to receive combusted exhaust gas for removal of at least a portion of the NO 2  therein.   
     
     
         47 . The system of  claim 46 , wherein the wet sulfuric acid process reactor is configured to receive combusted exhaust gas after combusted exhaust gas exits the selective catalytic reduction reactor.