Q&A

Question 3: Please discuss your best strategies to prevent overheating of steam reforming furnaces?

The question is general; however, there are a variety of steam reformer designs with different operating and control strategies used industrially so a general answer is provided. Operators are urged to consult with their technology providers or qualified engineering contractors for specific guidance on this issue.

Question 5: Does anyone have proven experience using promoted zinc oxide products for sulfur removal upstream of the reforming section? What improvement have you measured in the downstream catalyst performance?

Topsoe has installed our new promoted zinc oxide product HTZ-51 upstream the reformer section in a number of Ammonia, Hydrogen and Methanol plants. Topsoe’s promoted zinc oxide is also used as a purification absorbent upstream methanator units.

Question 14: How do you ensure that the reactor effluent stream is evenly divided when going to parallel exchangers?

Two phase reactor effluent flow to parallel exchanger trains need to be addressed during the design and initial piping layout phase. Once the system is installed very little can be done to evenly distribute the liquid and vapor.

Question 15: ULSD reactor feed/effluent heat exchanger leaks can be a big problem meeting product specifications. What are best practices for detecting and preventing leaks? Are there new technologies or mechanical specifications to prevent cross contamination?

With regard to feed/effluent exchanger leaks there are a number of actions that can be taken during the initial design phase of the unit.

Question 16: In your experience, are there documented cases of organic chlorides coming in with certain crudes? If so, what is their impact on hydrotreating units?

In researching this question with our corrosion experts, they identified this as a mature issue that has been well documented in NACE publications and international symposiums. These papers identify multiple cases of organic chlorides coming in with specific crude oils.

Question 24: For a hydrocracker with a debutanizer/stabilizer column, what corrosion issues do refineries experience in the feed and/or overhead systems? What have you done to mitigate the corrosion? What are your key considerations in optimizing these parameters

This answer assumes that the Debutanizer column is the first fractionation column design. In such columns, corrosion of the column bottoms, bottom outlet piping, reboiler tubes, fractionator feed heater tubes and the downstream fractionator is possible due to poor stripping of H2S.

Question 42: What are your best practices to minimize catalyst carry over to the main column on start up?

Catalyst loss events experienced while bringing the FCC online after a shutdown are troublesome as they can add significant cost and delay to the startup. Because the main air blower is run close to design conditions throughout the startup, losses are more frequently observed from the reactor side.

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