Q&A

(2014) Question 60: How does the mercury in crude distribute in your refinery (e.g., what units are affected)? What operating procedures or technology are you using to mitigate this issue?

How does the mercury in crude distribute in your refinery (e.g., what units are affected)? What operating procedures or technology are you using to mitigate this issue?

(2014) Question 61: What measurement and/or predictive methods are you using to determine crude oil blend compatibility?

Various methods exist to determine blend compatibility; one method would be a comparative asphaltene instability point determination via an anti-solvent titration, or another method used is the Wiehe insolubility number to solubility blend number method.

(2014) Question 62: What are the advantages and disadvantages to constructing “modular" refining process units versus traditional "stick built" units? What are the issues with each construction approach?

What are the advantages and disadvantages to constructing “modular" refining process units versus traditional "stick built" units? What are the issues with each construction approach?

(2014) Question 63: For the operating company, what are your crude unit typical run lengths between shutdowns? What factors do you consider when setting this run cycle?

For the operating company, what are your crude unit typical run lengths between shutdowns? What factors do you consider when setting this run cycle?

(2014) Question 64: Some crudes appear to have chlorides that are not readily removed in the desalter. What are sources for these un-desalted chlorides? How are the various un-desalted chlorides detected and mitigated?

The main source seems to be crystalline salt. A relatively new method to determine total chlorides is the Chlora instrument, desaltable chlorides can be determined by the extraction method, and the difference is taken as un-desaltable chlorides.

(2014) Question 65: What are the advantages and issues with different desalter wash water sources in a refinery? What issues do you experience by combining wash water from multiple sources?

The advantage is a reduction of freshwater use and sometimes a reduction in the load of contaminants(phenols) to the WTP. We have developed desalter washwater specs to prevent negative effects on desalter performance, fouling and corrosion. Oxygen, Ammonia, Hardness, TDS and Filterable are solids, the most obvious ones.

(2014) Question 66: What desalter instrumentation issues do you experience when switching from a light gravity feed to a heavy gravity feed?

The main influence is on level controllers, the most sensitive are the float type controllers but other instruments are also somewhat influenced by the crude Sulphur content.

(2014) Question 67: What is your experience with toxicity issues at the Water Treatment Plant as related to naphthenic acid content in desalter brine water? What strategies are you employing employed to mitigate this issue?

Some naphthenic acids will not partition into the water phase and normally do not create a wastewater issue. In case of washwater and brine pH’s above 8.5 the naphthenic acids can form a soap, and this can cause severe emulsion formation and oil carry-under to the WTP.

(2014) Question 68: What is your experience with toxicity issues at the Water Treatment Plant as related to naphthenic acid content in desalter brine water? What strategies are you employing employed to mitigate this issue?

The top causes of fouling with tight oil are asphaltene, destabilization on blending with asphaltene bearing crudes and also the potential for thermal production of foulant material.

(2014) Question 69: What is your experience with using thermal scans or other methods to monitor tube wall temperature furnaces?

This is a common practice in furnaces that have severe operation (VBU, Coker, etc.). All VBU’s have multiple fixed TMT measurements on all coils. Thermal imaging is used in furnaces that have specific TMT issues, it does require expertise and specialized thermal imaging cameras in order to get useful data. Thermal imaging will not work on tubes that have external fouling.

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