Method for treating coal tar using reactive distillation

Abstract

Methods of treating coal tar using reactive distillation are described. The methods include introducing a coal tar stream into a reactive distillation zone which has a reaction zone and a separation zone. The reaction zone contains a hydrotreating catalyst and an absorbent. The coal tar stream is contacted with a hydrogen stream in the reaction zone to remove contaminants from the coal tar stream, and the treated coal tar stream is separated into at least two fractions.

What is claimed is: 
     
         1 . A method of treating coal tar using reactive distillation comprising:
 introducing a coal tar stream into a reactive distillation zone, the reactive distillation zone comprising a reaction zone and a separation zone, the reaction zone containing a hydrotreating catalyst and an absorbent;   contacting the coal tar stream with a hydrogen stream in the reaction zone to remove sulfur compounds, nitrogen compounds, oxygenates, and metals from the coal tar stream; and   separating the treated coal tar stream into at least two fractions.   
     
     
         2 . The method of  claim 1  wherein the reactive distillation zone comprises a first reactive distillation column comprising a first reaction zone and a first separation zone, the first reaction zone containing a first hydrotreating catalyst and a first absorbent, and a second reactive distillation column comprising a second reaction zone and a second separation zone, the second reaction zone containing a second hydrotreating catalyst and a second absorbent. 
     
     
         3 . The method of  claim 2  wherein an outlet in the first reactive distillation column is in fluid communication with an inlet in the second reactive distillation column, further comprising:
 introducing a fraction from the first reactive distillation column into the second reactive distillation column; 
 contacting the fraction from the first reactive distillation column with a hydrogen stream in the second reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the fraction from the first reactive distillation column; and 
 separating the second treated fraction into at least two fractions. 
 
     
     
         4 . The method of  claim 3  wherein the second reaction zone further comprises a hydrocracking catalyst and wherein one of the fractions from the second fraction comprises naphtha. 
     
     
         5 . The method of  claim 2  further comprising;
 separating the coal tar stream into at least two fractions; 
 introducing a first fraction into the first reactive distillation column; 
 contacting the first fraction with a hydrogen stream in the first reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the first fraction; 
 separating the first treated fraction into at least two fractions; 
 introducing a second fraction into the second reactive distillation column; 
 contacting the second fraction with a hydrogen stream in the second reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the second fraction; and 
 separating the second treated fraction into at least two fractions. 
 
     
     
         6 . The method of  claim 5  wherein the second reaction zone further comprises a hydrocracking catalyst and wherein one of the fractions from the second treated fraction comprises naphtha. 
     
     
         7 . The method of  claim 2  wherein the first and second reactive distillation columns are operated at different pressures. 
     
     
         8 . The method of  claim 1  further comprising recovering at least one of the fractions. 
     
     
         9 . The method of  claim 1  wherein there are at least three separation zones alternating with at least two reaction zones. 
     
     
         10 . The method of  claim 1  wherein there are at least two reaction zones and wherein the hydrotreating catalyst in the first reaction zone is different from the hydrotreating catalyst in the second reaction zone. 
     
     
         11 . The method of  claim 1  further comprising removing at least one product from the coal tar stream before introducing the coal tar stream into the reactive distillation zone. 
     
     
         12 . The method of  claim 1  further comprising removing a pitch fraction from the coal tar stream before introducing the coal tar stream into the reactive distillation zone. 
     
     
         13 . The method of  claim 1  further comprising removing water from the coal tar stream before introducing the coal tar stream into the reactive distillation zone. 
     
     
         14 . The method of  claim 1  wherein the coal tar stream includes components having a boiling point from about C5 to 350° C. 
     
     
         15 . The method of  claim 1  wherein the absorbent has a surface area of at least about 200 m 2 /g. 
     
     
         16 . A method of treating coal tar using reactive distillation comprising:
 introducing a coal tar stream into a reactive distillation zone, the reactive distillation zone comprising a first reactive distillation column having a first reaction zone and a first separation zone, the first reaction zone containing a first hydrotreating catalyst and a first absorbent, and a second reactive distillation column comprising a second reaction zone and a second separation zone, the second reaction zone containing a second hydrotreating catalyst and a second absorbent;   contacting the coal tar stream with a hydrogen stream in the reaction zone to remove sulfur compounds, nitrogen compounds, oxygenates, and metals from the coal tar stream; and   separating the treated coal tar stream into at least two fractions.   
     
     
         17 . The method of  claim 16  wherein an outlet in the first reactive distillation column is in fluid communication with an inlet in the second reactive distillation column, further comprising:
 introducing a fraction from the first reactive distillation column into the second reactive distillation column; 
 contacting the fraction from the first reactive distillation column with a hydrogen stream in the second reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the fraction from the first reactive distillation column; and 
 separating the second treated fraction into at least two fractions. 
 
     
     
         18 . The method of  claim 17  wherein the second reaction zone further comprises a hydrocracking catalyst and wherein one of the fractions from the second fraction comprises naphtha. 
     
     
         19 . The method of  claim 16  further comprising;
 separating the coal tar stream into at least two fractions; 
 introducing a first fraction into the first reactive distillation column; 
 contacting the first fraction with a hydrogen stream in the first reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the first fraction; 
 separating the first treated fraction into at least two fractions; 
 introducing a second fraction into the second reactive distillation column; 
 contacting the second fraction with a hydrogen stream in the second reaction zone to remove sulfur compounds, nitrogen compounds, oxygenate, compounds, and metals from the second fraction; and 
 separating the second treated fraction into at least two fractions. 
 
     
     
         20 . The method of  claim 19  wherein the second reaction zone further comprises a hydrocracking catalyst and wherein one of the fractions from the second treated fraction comprises naphtha.