Q&A

(2014) Question 11: What is your experience with advanced control of sulfuric acid flow and strength?

What is your experience with advanced control of sulfuric acid flow and strength?

(2014) Question 12: The industry is recently discussing alternative metallurgy specifications for HF alkylation units. What is your experience on this issue?

One metallurgy issue that has been a hot topic in recent years is the specification for low Residual Elements (RE) in carbon steel for HF service. Based on recommendations made in NACE paper 03651, ASTM developed Supplemental Specifications for carbon steel that can be called out in purchase orders for steel that is to be used in HF Alky service

(2014) Question 13: What are the typical causes for failing jet fuel thermal oxidation (JFTOT) and aviation turbine (AVTUR) specifications?

The n-butane stream from an alkylation unit contains some organic fluorides. The fluoride must be removed in alumina treaters before being fed to an isomerization unit because the fluoride is a catalyst poison. When the fluoride is removed from the organic fluoride molecule, an olefin is formed.

(2014) Question 14: What are the advantages and challenges associated with alkylating amylenes?

What are the advantages and challenges associated with alkylating amylenes?

(2014) Question 15: What are the advantages and challenges associated with alkylating amylenes?

Normally clay downstream of extraction lasts a long time. Units utilizing glycol can damage the clay easily if there is any glycol carry over.

(2014) Question 16: In recent years the gasoline blend pool has shifted due to increased ethanol blending, higher volumes of high RVP material from processing lighter crudes, and other specifications changes. How are you taking advantage of these changes to optimize the gasoline processing units?

In recent years the gasoline blend pool has shifted due to increased ethanol blending, higher volumes of high RVP material from processing lighter crudes, and other specifications changes. How are you taking advantage of these changes to optimize the gasoline processing units?

(2014) Question 17: How does alkylate contribute to gasoline blend pool sulfur? With pending Tier III regulations, what steps are you taking to understand and control this contribution?

The feed to an HF Alkylation unit typically contains about 10 – 20 wppm of Sulfur. Nearly all of the sulfur in the HF Alky feed makes ASO, which mostly stays in the acid phase in the reactor. This ASO is removed from the acid in the Acid Regeneration (or rerun) column and so most of the sulfur typically is rejected from the unit in the ASO product stream.

(2014) Question 18: Do you have experience with gasoline corrosivity due to breakdown of organic fluorides from alkylate? Is the issue mitigated by increasing the residence time in tankage prior to blending?

Gasoline corrosivity should not be caused by organic fluorides in the alkylate. Organic fluorides themselves are not corrosive, and organic fluorides will not break down to HF in tankage at ambient temperatures.

(2014) Question 19: What are the common locations and adsorbent types for chloride treating beds in gasoline process units? What practices are you using to best manage this asset?

The question posed is specific for hydrogen chloride management and it is necessary to broaden it to encompass the numerous challenges associated with chloride induced fouling, corrosion and reliability issues in catalytic reformers, fired heaters and downstream hydroprocessing units.

(2014) Question 20: What are your current typical lead times for reforming, isomerization, naphtha, and FCC gasoline post-treating catalysts? What is your outlook for these lead times?

The key to minimizing ammonium chloride salt build-up in the Stabilizer system is to minimize organic nitrogen in the feed. Salt accumulation is generally either in the Overhead Condensers or on the trays in the top portion of the tower.

Find the answer to your technical question in AFPM's extensive Q&A database.

Q&A