Process for Determining Presence of Mesophase in Slurry Hydrocracking

Abstract

A process and apparatus is disclosed for converting heavy hydrocarbon feed into lighter hydrocarbon products. The heavy hydrocarbon feed is slurried with a catalyst comprising iron oxide and alumina to form a heavy hydrocarbon slurry and hydrocracked to produce lighter hydrocarbons. The slurry hydrocracking reaction can be controlled by measuring the production of mesophase using X-ray diffraction. Upon a mesophase yield fraction reaching a predetermined level, reaction conditions should be moderated to avoid excessive coke production.

1 . A method of operating a SHC reactor comprising:
 delivering heavy hydrocarbon feed, hydrogen and catalyst to a SHC reactor;   cracking the feed over catalyst in the presence of hydrogen at predetermined reaction conditions;   taking a sample of material from the SHC reactor;   determining the presence of mesophase in the sample by XRD; and   adjusting the reaction conditions in response at least in part to the determination of the fraction of mesophase in the sample.   
   
   
       2 . The method of  claim 1  further comprising:
 determining a fraction of mesophase in the sample;   determining the yield fraction of mesophase as the weight ratio of mesophase produced per hydrocarbon fed to the reactor using the fraction of mesophase in the sample; and   adjusting the reaction conditions in response to a determination that the yield fraction of mesophase is at or above 0.8%.   
   
   
       3 . The method of  claim 1  further comprising:
 scanning at least a portion of the sample with an XRD instrument;   plotting the data output from the XRD instrument by two theta degrees versus intensity;   identifying the presence of a peak at about 26 two theta degrees in the plot; and   adjusting the reaction conditions in response to the identification of a peak at 26 two theta degrees.   
   
   
       4 . The method of  claim 1  further comprising:
 separating solids in the sample from liquid;   dissolving the solids in the sample in a solvent;   separating insoluble solids in the sample from soluble solids; and   scanning the insoluble solids in with an XRD instrument.   
   
   
       5 . The method of  claim 1  further including:
 blending the insoluble solids with a predetermined concentration of a standard material before scanning the sample; and   comparing the area under the peak between about 20 and about 29.5 degrees two theta excluding the peak for the standard on the plot to the area under the peak for the standard to proportionally determine the concentration of mesophase in the sample.   
   
   
       6 . The method of  claim 1  further including calculating the yield fraction of mesophase produced per weight of hydrocarbon fed to a SHC reactor by using the concentration of mesophase in the sample. 
   
   
       7 . The method of  claim 3  further including adjusting the reaction conditions to avoid excessive coking if the yield fraction of mesophase is at or above 0.5 wt-%. 
   
   
       8 . A method of determining the presence of mesophase in a hydrocarbon material comprising:
 scanning a sample of hydrocarbon material from a SHC reaction with an x-ray diffraction (XRD) instrument;   plotting the data output from the XRD instrument by two theta degrees versus intensity;   identifying the existence or absence of a peak at about 26 two theta degrees.   
   
   
       9 . The method of  claim 8  further including blending the hydrocarbon material with a solvent, decanting a liquid phase and obtaining the solids to provide the sample of hydrocarbon material. 
   
   
       10 . The method of  claim 8  wherein the solvent is toluene. 
   
   
       11 . The method of  claim 9  further including drying the solids providing the sample before scanning the sample. 
   
   
       12 . The method of  claim 8  wherein the existence or absence of a peak is identified at 26 two theta degrees plus or minus 0.3 two theta degrees. 
   
   
       13 . The method of  claim 8  wherein identifying the existence or absence of a peak at about 26 two theta degrees includes:
 adding an internal standard to the sample to obtain a predetermined concentration of standard in the sample; and   determining the concentration of mesophase in the sample of hydrocarbon material by calculating the area under the peak at 26 two theta degrees in the plot and comparing it to the area of the peak for the internal standard to proportionally determine the concentration of mesophase relative to the predetermined concentration of standard.   
   
   
       14 . The method of  claim 13  wherein the known internal standard peak is silicon. 
   
   
       15 . The method of  claim 13  wherein the area under the peak at about 26 two theta degrees includes all of the peaks between about 20 and about 29.5 two theta degrees. 
   
   
       16 . The method of  claim 15  further including the step of excluding areas of peaks associated with known hydrocarbons that are not mesophase from the area under the peak at about 26 degrees two theta. 
   
   
       17 . The method of  claim 15  further including the step of excluding areas of peaks associated with the standard if it generates a peak within the range between 20 and 29.5 two theta degrees. 
   
   
       18 . A method of determining the concentration of mesophase in a hydrocarbon material from a SHC reaction comprising:
 scanning a sample of hydrocarbon material blended with a predetermined concentration of a standard material with an x-ray diffraction (XRD) instrument;   plotting the data output from the XRD instrument by two theta degrees versus intensity;   determining the area under the peak at about 26 two theta degrees in the plot; and   comparing the area under the peak at about 26 two theta degrees to a peak for the internal standard in the sample to proportionally determine the concentration of mesophase in the sample.   
   
   
       19 . The method of  claim 18  wherein the area under the peak at about 26 degrees includes all of the peaks between about 20 and about 29.5 two theta degrees. 
   
   
       20 . The method of  claim 19  further including the step of excluding areas of peaks associated with the standard if it generates a peak within the range between 20 and 29.5 two theta degrees.