Menu
Search
Filters
Close
Menu

Accelerated Corrosion of 304H SS in RFCC Regenerators Involving Low Temperature Eutectic-Forming Salts

Picture for Accelerated Corrosion of 304H SS in RFCC Regenerators Involving Low Temperature Eutectic-Forming Sal
Available for download

This article presents findings on type II high temperature (650-800ºC) corrosion in Residue Fluid Catalytic cracking (RFCC) regenerator service (alloy SS304H) and examines the possible strategies for alloy upgrade in RFCC service.

Product Number: 51317--8915-SG
ISBN: 8915 2017 CP
Author: Jayant Nair
Publication Date: 2017
Industry: Petroleum Refining
$0.00
$20.00
$20.00

Residue Fluid Catalytic cracking (RFCC) is a valuable subset of the more conventional Fluid Catalytic cracking (FCC) process that generates most of the world’s gasoline pool. The critical distinction of RFCC involves the processing of “dirty” atmospheric residue (AR) directly from crude distillation and not just the more conventional use of relatively pure gasoil feedstocks. By direct catalytic cracking of “dirty” residue the refiner benefits economically by avoiding a whole intermediate process, namely vacuum distillation. Unfortunately direct FCC processing of atmospheric residue (AR) exposes the vessel internals to geological salts naturally present in crude oil but concentrated in the residue fraction during the distillation process. Internals of regenerator vessels (cyclones, refractory anchors, hexmesh, and cross bracing) are typically manufactured in UNS(1) S30409, which is sensitive to corrosive low melting point eutectics. In the normal crude distillation process, metals are concentrated by approximately two-fold in AR. Thereafter coke formed on the catalyst particles is burnt off in a regeneration process leaving much higher quantities of metal salts in a high temperature environment between 720-800 ºC. Chemical analysis of salt scabs covering deep pits show higher concentrations of Vanadium and Sodium which are consistent with low melting point eutectic corrosion. This article presents findings on type II high temperature (650-800ºC) corrosion in RFCC regenerator service (alloy SS304H) and examines the possible strategies for alloy upgrade in RFCC service.

Key Words: RFCC, Hot Corrosion, SS304H, low melting-point, eutectic.

Residue Fluid Catalytic cracking (RFCC) is a valuable subset of the more conventional Fluid Catalytic cracking (FCC) process that generates most of the world’s gasoline pool. The critical distinction of RFCC involves the processing of “dirty” atmospheric residue (AR) directly from crude distillation and not just the more conventional use of relatively pure gasoil feedstocks. By direct catalytic cracking of “dirty” residue the refiner benefits economically by avoiding a whole intermediate process, namely vacuum distillation. Unfortunately direct FCC processing of atmospheric residue (AR) exposes the vessel internals to geological salts naturally present in crude oil but concentrated in the residue fraction during the distillation process. Internals of regenerator vessels (cyclones, refractory anchors, hexmesh, and cross bracing) are typically manufactured in UNS(1) S30409, which is sensitive to corrosive low melting point eutectics. In the normal crude distillation process, metals are concentrated by approximately two-fold in AR. Thereafter coke formed on the catalyst particles is burnt off in a regeneration process leaving much higher quantities of metal salts in a high temperature environment between 720-800 ºC. Chemical analysis of salt scabs covering deep pits show higher concentrations of Vanadium and Sodium which are consistent with low melting point eutectic corrosion. This article presents findings on type II high temperature (650-800ºC) corrosion in RFCC regenerator service (alloy SS304H) and examines the possible strategies for alloy upgrade in RFCC service.

Key Words: RFCC, Hot Corrosion, SS304H, low melting-point, eutectic.

Product tags
Also Purchased
Picture for Failure of RFCC Catalyst Cooler Aeration Piping System (Cat Cooler Internals)
Available for download

51318-11086-Failure of RFCC Catalyst Cooler Aeration Piping System (Cat Cooler Internals)

Product Number: 51318-11086-SG
Author: Ntsikelelo Ngonyoza / Abdulaziz Al Hamdi / Aliaa Al Balushi / Robin Blakey
Publication Date: 2018
$20.00

Degradation mechanisms experienced by a refinery’s RFCC catalyst cooler aeration piping system. Analysis of the most recent and a past failure determined the metallurgical and mechanical degradation mechanism(s) that led to these failures.
Picture for 10360 Description and Explanation of an FCC Overhead System Unexpected Corrosion
Available for download

10360 Description and Explanation of an FCC Overhead System Unexpected Corrosion

Product Number: 51300-10360-SG
ISBN: 10360 2010 CP
Author: Matthieu Devallée
Publication Date: 2010
$20.00

Case study: A leak occurred in a Fluid Catalytic Cracking unit main fractionator overhead line elbow in June 2006. Following this leak, investigations showed acidic corrosion-erosion in the overhead circuit. This type of corrosion was unexpected in this circuit.
Picture for An Integrated Approach to Optimizing Corrosion Control for Refinery Process and Boiler Systems
Available for download

An Integrated Approach to Optimizing Corrosion Control for Refinery Process and Boiler Systems

Product Number: 51317--9377-SG
ISBN: 9377 2017 CP
Author: Gregg Robinson
Publication Date: 2017
$20.00

This paper will discuss the design, application, and benefits of utilizing an integrated approach to develop programs to both protect the steam system and avoid negative impact to the refinery process. Several short case studies are included.

 
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support