Q&A

(2016) Question 1: Do you have experience isolating air coolers to water-wash the process side while the unit continues to operate? What safety concerns do you consider beforeremoving this equipment from operation?

Safe isolation with block valves can also be an issue, especially in high pressure units with two-phase flow. We have had experience with water-washing exchangers and air coolers offline.

(2016) Question 2: What procedures do you use to test alkylation unit rapid deinventory systems? Do you perform a functional test using acid?

High level guidelines and philosophy of testing of the valves (as well as all other components) of HF alky safety systems –including rapid acid deinventory or “Dump” systems -is covered in API RP 751 section 2.3.6. The bits of that section that are directly applicable to dump valve testing suggest that the testing procedure should include valve stroking and testing of primary elements and controls. It also says that in addition to individual component tests, each active mitigation system as a whole should be tested to confirm that the system will work as designed. It also says that a service history should be maintained to assist in identifying and correcting problem areas.

(2016) Question 3: What process safety PSM) factors do you consider when contemplating a reformer unit rate increase?

Any change should be handled through the MOC (management of change) process, according to OSHA 1910.119: Process Safety Management of Highly Hazardous Chemicals. This standard includes requirements for preventing or minimizing the consequences of catastrophic releases that may result in toxic, fire, or explosion hazards.

(2016) Question 4: The economic benefit for propylene and amylene alkylation is improving. What considerations do you use in the feed pretreatment and alkylation unit operations before increasing these feeds?

Increased processing of propylene and amylene feedstocks in alkylation (alky) units does bring challenges, but most will depend on the configuration of the existing unit and whether any of these feedstocks have been processed before.

(2016) Question 5: What are the typical dispositions of coker olefins, light coker naphtha, and heavy coker naphtha in refineries that you employ? How are the sulfur contaminants, such as dimethyl sulfide and dimethyl disulfide, best removed from these streams?

This question asks about the fate of coker olefins and coker naphthas. What we are looking at here are the three coker product streams, which include coker LPGs (liquefied petroleum gas), your C3s(propane/propylenes) and C4s (butane and butylenes), and light and heavy coker naphthas, which must be further processed before they can be blended or sold into the gasoline pool. Coker products are really a challenging feedstock.

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Q&A

(2016) Question 1: Do you have experience isolating air coolers to water-wash the process side while the unit continues to operate? What safety concerns do you consider beforeremoving this equipment from operation?

(2016) Question 2: What procedures do you use to test alkylation unit rapid deinventory systems? Do you perform a functional test using acid?

(2016) Question 3: What process safety PSM) factors do you consider when contemplating a reformer unit rate increase?

(2016) Question 4: The economic benefit for propylene and amylene alkylation is improving. What considerations do you use in the feed pretreatment and alkylation unit operations before increasing these feeds?

(2016) Question 5: What are the typical dispositions of coker olefins, light coker naphtha, and heavy coker naphtha in refineries that you employ? How are the sulfur contaminants, such as dimethyl sulfide and dimethyl disulfide, best removed from these streams?