recklesskid
Chemical
Hi,
In our CCRU, we are injecting DMDS to our feed (Heavy Virgin Naphtha (HVN) from Naphtha Hydrotreating unit)to maintain a sulfur content of 0.3 - 0.5 ppm. However, the laboratory results for the CCRU Feed has been indicating 0.01 wppm of sulfur for a while now. We have verified the injection and we have also tested for H2S in the recycle gas. These all indicates that sulfur is definitely present in the system as opposed to what is indicated by the lab result.
In the laboratory, we are using ASTM D5623 to test for sulfur. As an experiment, we prepared standards for different solvents (10%toluene in isooctane and HVN) each mixed with Thiophene, Dibutyl SUlfide (DBS) and DMDS. The combination of
a. 10%toluene in isooctane and Thiophene
b. 10%toluene in isooctane and DBS
c. 10%toluene in isooctane and DMDS
d. HVN and Thiophene
e. HVN and DBS
all indicated a linear relatonship. Meaning, the expected concentration for every dilution is being read correctly by the GC.
However, only the combination of DMDS and HVN gave an exponentially decreasing DMDS for every step decrease in concentration. We conducted an experiment with HVN and DMDS sand obtained their sulfur content using our Agilent sulfur GC. We diluted the DMDS to 2.5 ppm sulfur using 10%toluene in isooctane as per ASTM D5623.
With this, is it possible that there exists a "reaction" between the HVN and DMDS in which the sulfur is being coated and therefore not easily read by the GC?
THank you.
In our CCRU, we are injecting DMDS to our feed (Heavy Virgin Naphtha (HVN) from Naphtha Hydrotreating unit)to maintain a sulfur content of 0.3 - 0.5 ppm. However, the laboratory results for the CCRU Feed has been indicating 0.01 wppm of sulfur for a while now. We have verified the injection and we have also tested for H2S in the recycle gas. These all indicates that sulfur is definitely present in the system as opposed to what is indicated by the lab result.
In the laboratory, we are using ASTM D5623 to test for sulfur. As an experiment, we prepared standards for different solvents (10%toluene in isooctane and HVN) each mixed with Thiophene, Dibutyl SUlfide (DBS) and DMDS. The combination of
a. 10%toluene in isooctane and Thiophene
b. 10%toluene in isooctane and DBS
c. 10%toluene in isooctane and DMDS
d. HVN and Thiophene
e. HVN and DBS
all indicated a linear relatonship. Meaning, the expected concentration for every dilution is being read correctly by the GC.
However, only the combination of DMDS and HVN gave an exponentially decreasing DMDS for every step decrease in concentration. We conducted an experiment with HVN and DMDS sand obtained their sulfur content using our Agilent sulfur GC. We diluted the DMDS to 2.5 ppm sulfur using 10%toluene in isooctane as per ASTM D5623.
With this, is it possible that there exists a "reaction" between the HVN and DMDS in which the sulfur is being coated and therefore not easily read by the GC?
THank you.
