PTQ
(http://www.eptq.com/) has published its
annual Catalysis issue. As always, it is
fascinating reading. Here are excerpts
from the articles in this issue …
///////
Automating catalyst withdrawal for improved safety
Kate Hovey and Rick Fisher, Johnson Matthey
Catalyst withdrawals can be carried out continuously and reliably, minimising operator risk and maintaining the integrity of withdrawal piping
It is 2018 and we have cars that drive themselves, auto-landing planes, and household thermostats that can detect when you are getting close to home so they switch on the heating before you arrive. … So why are some hazardous operations left to be carried out manually when they can be automated by implementing some very simple engineering design?
This article discusses the unsafe and unreliable FCC catalyst withdrawal practices carried out today by many refiners around the globe. This can very easily be a thing of the past, and a solution has been commercially demonstrated by MPC proving that catalyst withdrawals can be carried out continuously and reliably, minimising operator risk and maintaining the integrity of the withdrawal piping. The latest Mark-II design of the continuous CWS includes recent developments aimed at further improving efficiency and reducing costs compared to the initial prototype design. A patented helical finned piping section is cooled using an induced draft fan rather than a centrifugal blower which significantly reduces the footprint. Helical finned piping additionally eliminates the requirement for expansion joints which helps to reduce costs and improve reliability. And finally, the Mark-II design includes two collection vessels which can operate in such a way that there is no requirement to isolate catalyst withdrawals during normal operation, improving the stability and reliability of the withdrawal system for a fully continuous approach.
///////
Producing ultra low sulphur gasoline with octane retention
A drop-in catalyst enabled refiners to meet ultra low sulphur gasoline requirements with more severe feedstocks while retaining octane barrels
Jignesh Fifadara, Albemarle
There are several operational and performance unknowns associated with reducing the average sulphur content of gasoline to ≤10 ppmw. To address this challenge and meet regulatory requirements, refiners are carrying out extensive technical and economic studies of the various catalyst drop-in solutions available in the market to assess which would provide maximum profitability and performance for their refineries. The processing of FCC naphtha takes on an even more important role in meeting the new regulatory changes.
Although the gasoline pool comes from various sources in the refinery, full range FCC naphtha typically accounts for 30-50% of the overall gasoline blend and is the biggest contributor to sulphur. Operating selective hydrodesulphurisation (HDS) gasoline units to process FCC naphtha effectively generally entails lower investment and operating costs.
At Refinery A, RT-235 catalyst was utilised to optimise performance when making ultra low sulphur gasoline while introducing a more severe feedstock and controlling the octane loss across the unit to between 2 and 3 RON. At Refinery B, the transition to RT-235 catalyst resulted in twice as much HDS activity. Improved selectivity with RT-235 catalyst for octane retention enabled Refinery B to save more than 1 RON in comparison with the previous cycle, which resulted in extremely favourable refinery economics and profitability.
///////
Interpreting FCC equilibrium catalyst data
Alexis Shackleford, BASF
As part of best practice in fluid catalytic cracking (FCC) unit monitoring, routine analysis of equilibrium FCC catalyst (Ecat) and fines is vital to maximise profitability and reliability. Ecat and fines analysis provides valuable information on the FCC unit to assess operation, monitor performance, troubleshoot, ensure reliability, and optimise the unit. BASF routinely analyses Ecat and fines data for units around the world. This article describes the testing and interpretation of the data.
///////
Catalyst passivation for safer, more efficient turnarounds
Alvaro Barrueto, ENAP Refinerías
Ian Baxter and Gary Welch, Cat Tech International
Since hydrotreating and hydrocracking were introduced to the refining industry in the mid-20th century, it has always been a struggle to safely remove the catalyst from the reactors. These catalysts typically contain a combination of molybdenum or tungsten with nickel or cobalt. The catalysts are manufactured as stable metal oxides. During the activation process, the metal oxides are converted to sulphides. These metal sulphides are very reactive and, when exposed to air, can spontaneously ignite. This not only creates a fire hazard but can also release toxic sulphur dioxide, making it difficult to remove them safely from reactors.
The industry solution was to remove the catalyst under nitrogen. With air eliminated, the catalyst could be safely unloaded, packaged in hermetically sealed containers, and sent for disposal, reclamation or regeneration. This created a new industry for ‘catalyst handlers’. These professionals would enter reactors under nitrogen with breathing apparatus to vacuum or shovel out catalyst.
Catalyst Passivation Technology provided an alternative methodology for ENAP to improve the safety and reliability of catalyst changeout for the MHC. Alvaro Barrueto, Maintenance Engineer at the Bio refinery, said, “The passivation technology enabled us to apply a safer system of work, eliminating two of the major hazards associated with catalyst removal, nitrogen while unloading catalyst and inert entry into confined spaces. The modified shutdown procedure allowed us to reduce the overall downtime and gave us access to the reactors sooner.”
///////
Prompt start-up with cracked feed
Michael Martinez and Guillaume Vincent, Porocel
Porocel developed actiCAT Shield technology to offer cracked stock protection for refineries hydrotreating cracked stocks from their FCC and coker units. Catalysts that are conditioned with the technology do not need to wait during a three day break-in period as cracked feed can be introduced immediately while maintaining catalytic performance throughout the cycle length. A proprietary technique applies a temporary carbonaceous layer with the sulphur to moderate catalyst hyperactivity. This in turn protects against rapid deactivation associated with the early introduction of high olefin and aromatic containing cracked feeds such as light cycle oil or coker components. This saves time and money as cracked feed can be introduced earlier and this eliminates the inconvenience of storing cracked feed during start-up.
With the refining industry’s focus on value, Porocel’s latest development, actiCAT Shield technology, provides high hydroprocessing catalyst activity with economic value. It saves refiners time and money by enabling the prompt introduction of cracked feeds while maintaining catalytic performance. actiCAT Shield provides the convenience of speeding up the refiner’s start-up over in situ presulphiding by reducing the presulphiding time as well as eliminating the three day break-in period. The opportunity to introduce cracked feed promptly eliminates the refiner’s storage needs, resulting in significant cost savings.
///////
Hydroprocessing rate increase using shaped charges
Adrienne Van Kooperen, Criterion Catalysts & Technologies/Zeolyst International
James Esteban, Criterion Catalysts & Technologies
Brandon Murphy, Marathon Petroleum Company
This article provides two examples of hydrocracking units processing significantly higher rates as a direct result of Criterion’s new hydrocracking catalyst shape. Criterion and its customers have seen that a fine balance of activity and pressure drop has long since created a challenge when considering the maximisation of performance for hydroprocessing and hydrocracking units. It is especially a critical balance for high profile units in hydrocracking service that receive large margins for product upgrades and also have high incentives for incremental processing capacity.
Criterion developed the Advanced Trilobe eXtra (ATX) catalyst shape to allow hydrocracking units to reduce pressure drop and improve activity simultaneously. There are several significant advantages of the ATX shape (see Catalyst size and shape are critical contributors to hydroprocessing reactor performance
///////
In-line H2S analysis during sulphiding
Francis Humblot, Arkema
Hydroprocessing catalysts are generally made of a carrier (alumina, zeolite, for instance) that disperses active sites containing a main hydrogenation metal (molybdenum or tungsten) and an activity promoter (nickel, cobalt). Generally, the catalyst is delivered at the refinery in oxide form, which is inactive and safe to be handled and loaded under air into the fixed bed reactor(s). During the start-up phase of the unit, the oxide form of the catalyst has to be converted to its sulphided form, which is active for all hydroprocessing reactions. This activation is generally achieved thanks to the injection of a sulphur compound that starts to decompose at low temperature (~200°C). Dimethyldisulphide has become the standard sulphiding agent for more than 20 years because of its decomposition chemistry that fits the catalysts’ needs and its physical properties such as its high sulphur concentration (68%).
One of the main parameters to manage the dimethyldisulphide (DMDS) injection flow rate during this activation is the H2S concentration in the hydrogen recycle gas. Today, refiners obtain, manually every hour, the H2S concentration information with H2S reactive tubes. Due to the high toxicity of H2S and flammability of hydrogen, this measurement is a risky operation and the refinery has to dedicate a workforce to this task during the busy unit start-up period. Moreover, the accuracy of the result depends on the experience of the operators and a faster response analysis, more than every hour, would be welcome to antic- In-line analysis enables constant measurement of H2S concentration in hydrogen recycle gas during catalyst sulphiding.
///////
TIP: I always enjoy reading the PTQ Catalysis issue. Each article is written by experts in the field. However, I always try to remember that, ultimately, the author is promoting a product or process offered by his/her employer. Critical thinking is key.
///////
Automating catalyst withdrawal for improved safety
Kate Hovey and Rick Fisher, Johnson Matthey
Catalyst withdrawals can be carried out continuously and reliably, minimising operator risk and maintaining the integrity of withdrawal piping
It is 2018 and we have cars that drive themselves, auto-landing planes, and household thermostats that can detect when you are getting close to home so they switch on the heating before you arrive. … So why are some hazardous operations left to be carried out manually when they can be automated by implementing some very simple engineering design?
This article discusses the unsafe and unreliable FCC catalyst withdrawal practices carried out today by many refiners around the globe. This can very easily be a thing of the past, and a solution has been commercially demonstrated by MPC proving that catalyst withdrawals can be carried out continuously and reliably, minimising operator risk and maintaining the integrity of the withdrawal piping. The latest Mark-II design of the continuous CWS includes recent developments aimed at further improving efficiency and reducing costs compared to the initial prototype design. A patented helical finned piping section is cooled using an induced draft fan rather than a centrifugal blower which significantly reduces the footprint. Helical finned piping additionally eliminates the requirement for expansion joints which helps to reduce costs and improve reliability. And finally, the Mark-II design includes two collection vessels which can operate in such a way that there is no requirement to isolate catalyst withdrawals during normal operation, improving the stability and reliability of the withdrawal system for a fully continuous approach.
///////
Producing ultra low sulphur gasoline with octane retention
A drop-in catalyst enabled refiners to meet ultra low sulphur gasoline requirements with more severe feedstocks while retaining octane barrels
Jignesh Fifadara, Albemarle
There are several operational and performance unknowns associated with reducing the average sulphur content of gasoline to ≤10 ppmw. To address this challenge and meet regulatory requirements, refiners are carrying out extensive technical and economic studies of the various catalyst drop-in solutions available in the market to assess which would provide maximum profitability and performance for their refineries. The processing of FCC naphtha takes on an even more important role in meeting the new regulatory changes.
Although the gasoline pool comes from various sources in the refinery, full range FCC naphtha typically accounts for 30-50% of the overall gasoline blend and is the biggest contributor to sulphur. Operating selective hydrodesulphurisation (HDS) gasoline units to process FCC naphtha effectively generally entails lower investment and operating costs.
At Refinery A, RT-235 catalyst was utilised to optimise performance when making ultra low sulphur gasoline while introducing a more severe feedstock and controlling the octane loss across the unit to between 2 and 3 RON. At Refinery B, the transition to RT-235 catalyst resulted in twice as much HDS activity. Improved selectivity with RT-235 catalyst for octane retention enabled Refinery B to save more than 1 RON in comparison with the previous cycle, which resulted in extremely favourable refinery economics and profitability.
///////
Interpreting FCC equilibrium catalyst data
Alexis Shackleford, BASF
As part of best practice in fluid catalytic cracking (FCC) unit monitoring, routine analysis of equilibrium FCC catalyst (Ecat) and fines is vital to maximise profitability and reliability. Ecat and fines analysis provides valuable information on the FCC unit to assess operation, monitor performance, troubleshoot, ensure reliability, and optimise the unit. BASF routinely analyses Ecat and fines data for units around the world. This article describes the testing and interpretation of the data.
///////
Catalyst passivation for safer, more efficient turnarounds
Alvaro Barrueto, ENAP Refinerías
Ian Baxter and Gary Welch, Cat Tech International
Since hydrotreating and hydrocracking were introduced to the refining industry in the mid-20th century, it has always been a struggle to safely remove the catalyst from the reactors. These catalysts typically contain a combination of molybdenum or tungsten with nickel or cobalt. The catalysts are manufactured as stable metal oxides. During the activation process, the metal oxides are converted to sulphides. These metal sulphides are very reactive and, when exposed to air, can spontaneously ignite. This not only creates a fire hazard but can also release toxic sulphur dioxide, making it difficult to remove them safely from reactors.
The industry solution was to remove the catalyst under nitrogen. With air eliminated, the catalyst could be safely unloaded, packaged in hermetically sealed containers, and sent for disposal, reclamation or regeneration. This created a new industry for ‘catalyst handlers’. These professionals would enter reactors under nitrogen with breathing apparatus to vacuum or shovel out catalyst.
Catalyst Passivation Technology provided an alternative methodology for ENAP to improve the safety and reliability of catalyst changeout for the MHC. Alvaro Barrueto, Maintenance Engineer at the Bio refinery, said, “The passivation technology enabled us to apply a safer system of work, eliminating two of the major hazards associated with catalyst removal, nitrogen while unloading catalyst and inert entry into confined spaces. The modified shutdown procedure allowed us to reduce the overall downtime and gave us access to the reactors sooner.”
///////
Prompt start-up with cracked feed
Michael Martinez and Guillaume Vincent, Porocel
Porocel developed actiCAT Shield technology to offer cracked stock protection for refineries hydrotreating cracked stocks from their FCC and coker units. Catalysts that are conditioned with the technology do not need to wait during a three day break-in period as cracked feed can be introduced immediately while maintaining catalytic performance throughout the cycle length. A proprietary technique applies a temporary carbonaceous layer with the sulphur to moderate catalyst hyperactivity. This in turn protects against rapid deactivation associated with the early introduction of high olefin and aromatic containing cracked feeds such as light cycle oil or coker components. This saves time and money as cracked feed can be introduced earlier and this eliminates the inconvenience of storing cracked feed during start-up.
With the refining industry’s focus on value, Porocel’s latest development, actiCAT Shield technology, provides high hydroprocessing catalyst activity with economic value. It saves refiners time and money by enabling the prompt introduction of cracked feeds while maintaining catalytic performance. actiCAT Shield provides the convenience of speeding up the refiner’s start-up over in situ presulphiding by reducing the presulphiding time as well as eliminating the three day break-in period. The opportunity to introduce cracked feed promptly eliminates the refiner’s storage needs, resulting in significant cost savings.
///////
Hydroprocessing rate increase using shaped charges
Adrienne Van Kooperen, Criterion Catalysts & Technologies/Zeolyst International
James Esteban, Criterion Catalysts & Technologies
Brandon Murphy, Marathon Petroleum Company
This article provides two examples of hydrocracking units processing significantly higher rates as a direct result of Criterion’s new hydrocracking catalyst shape. Criterion and its customers have seen that a fine balance of activity and pressure drop has long since created a challenge when considering the maximisation of performance for hydroprocessing and hydrocracking units. It is especially a critical balance for high profile units in hydrocracking service that receive large margins for product upgrades and also have high incentives for incremental processing capacity.
Criterion developed the Advanced Trilobe eXtra (ATX) catalyst shape to allow hydrocracking units to reduce pressure drop and improve activity simultaneously. There are several significant advantages of the ATX shape (see Catalyst size and shape are critical contributors to hydroprocessing reactor performance
///////
In-line H2S analysis during sulphiding
Francis Humblot, Arkema
Hydroprocessing catalysts are generally made of a carrier (alumina, zeolite, for instance) that disperses active sites containing a main hydrogenation metal (molybdenum or tungsten) and an activity promoter (nickel, cobalt). Generally, the catalyst is delivered at the refinery in oxide form, which is inactive and safe to be handled and loaded under air into the fixed bed reactor(s). During the start-up phase of the unit, the oxide form of the catalyst has to be converted to its sulphided form, which is active for all hydroprocessing reactions. This activation is generally achieved thanks to the injection of a sulphur compound that starts to decompose at low temperature (~200°C). Dimethyldisulphide has become the standard sulphiding agent for more than 20 years because of its decomposition chemistry that fits the catalysts’ needs and its physical properties such as its high sulphur concentration (68%).
One of the main parameters to manage the dimethyldisulphide (DMDS) injection flow rate during this activation is the H2S concentration in the hydrogen recycle gas. Today, refiners obtain, manually every hour, the H2S concentration information with H2S reactive tubes. Due to the high toxicity of H2S and flammability of hydrogen, this measurement is a risky operation and the refinery has to dedicate a workforce to this task during the busy unit start-up period. Moreover, the accuracy of the result depends on the experience of the operators and a faster response analysis, more than every hour, would be welcome to antic- In-line analysis enables constant measurement of H2S concentration in hydrogen recycle gas during catalyst sulphiding.
///////
TIP: I always enjoy reading the PTQ Catalysis issue. Each article is written by experts in the field. However, I always try to remember that, ultimately, the author is promoting a product or process offered by his/her employer. Critical thinking is key.
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