Q&A

(2010) Question 68: Do you see any benefit in continuing to steam strip crude tower distillate cuts since these side streams require further processing in down stream hydrotreaters?

We have observed definite benefits to steam stripping the distillate cuts and have been working to determine whether the benefit is worth the cost. The main purpose for distillate side strippers is to control product flash with a secondary purpose of lifting lighter material and affecting the product cuts.

(2010) Question 69: What do you see as the critical considerations for wash bed design in high C-factor vacuum columns? How does one determine bed type, depth, and appropriate wash oil distributor design?

A new vacuum column will typically be designed for a C-factor of 0.36 ft/sec above the wash zone which is normally the section with the highest vapor velocity. A high C-factor situation (say above 0.43) would then involve an existing unit operating well above its original design point.

(2010) Question 78: In your experience, how effective and reliable are hydrocyclones, electrostatic separator, additives, and filters in reducing the ash content of the slurry?

There are basically 3 types of ways to reduce the ash content in slurry oil. They are electrostatic separators, additives with settling and filters. They all have their advantages and disadvantages, and they all do a reasonable job in reducing ash in slurry.

(2019) Question 33: What downstream processing issues have been associated with the overfeed of NaOH at the crude unit?

Caustic is injected with the crude charge on some units to reduce chlorides in the crude overhead system and impact the salting and corrosion potential.

Question 34: What strategies (operational, technological, logistical) do you consider for slurry streams that will not meet the IMO specifications?

What strategies (operational, technological, logistical) do you consider for slurry streams that will not meet the IMO specifications?

(2019) Question 35: What is the importance of sodium to reliability in the coker? What are some of the potential sources of the sodium in coker feed? In light of IMO how should sodium be managed in purchased coker feed?

Sodium in the coker feed can be introduced via sodium content of the salts in crude, caustic addition at the crude unit for corrosion control purposes, as a contaminant in recovered oil material in the refinery, sodium content of other purchased feedstocks (as mentioned in the question) among others.

(2019) Question 36: With higher anticipated charge rates at the coker due to IMO, what are your best practices around defoamer application to minimize impact on hydrotreater catalyst life?

With higher anticipated charge rates at the coker due to IMO, what are your best practices around defoamer application to minimize impact on hydrotreater catalyst life?

(2019) Question 37: With higher anticipated charge rates at the coker due to IMO, what are your best practices around defoamer application to minimize impact on hydrotreater catalyst life?

As equipment ages and reaches end of useful life, the opportunity arises with necessary replacement to include enhancements or upgrades at little additional cost.

(2019) Question 40: What rationale have you used to justify replacing the FCCU regenerator or reactor vessel?

What rationale have you used to justify replacing the FCCU regenerator or reactor vessel?

(2019) Question 41: How reliable are main air blower check valves?  What are some improved designs or some things to avoid?  Are there any alternatives?  If multiple branches, is there one check valve in the main branch or one check valve per branch, where is it located?  What is your maintenance or inspection best practices?

How reliable are main air blower check valves?  What are some improved designs or some things to avoid?  Are there any alternatives?  If multiple branches, is there one check valve in the main branch or one check valve per branch, where is it located?  What is your maintenance or inspection best practices?

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