FIG. 4 shows the effect on catalyst activity when Source A (without CO guard beds) goes offline and then comes online again. The daily average catalyst activity is plotted for an entire month when the polymerization unit is running at the same
residence time and at the same H2 con-
centration (same polymer grade) in a gas- phase reactor.
FIG. 4 reveals that catalyst activity is ap- proximately 25% lower when untreated propylene feed Source A is online. This translates into an additional cost of approxi- mately $5 million/yr due to excessive cata- lyst consumption.
FIG. 5 illustrates the effect that varying CO levels in propylene feed Source A have on catalyst activity for a period of nine days on a real-time basis. The figure shows that the CO level is in- creasing while catalyst activity is dropping. A loss of approxi- mately 45% catalyst activity is seen when CO levels go up from approximately 90 ppb to approximately 250 ppb.
FIG. 6 portrays a relationship in a commercial reactor be- tween levels of CO in a propylene feed vs. catalyst activity when other process parameters are kept constant. A simple extrapola- tion yields a further activity rise by 10% to 13% if there is no CO contamination in the propylene feed.
Solution. Since the source of the CO contamination was known and the average CO level was confirmed by the online CO ana- lyzer, it was easier to calculate lost revenue. Various options were evaluated against the cost and feasibility of carrying out the change.
In FIG. 7, it was proposed to partially fill the existing dryer on Source B with CO-removal catalysts. This proposal would save on potential capital and construction costs associated with in- stalling a new bed, associated piping and required plot space. All operational aspects and regeneration were carefully evaluated and documented accordingly.
The end result was a new mixed bed with a molecular sieve and CO-removal catalysts. After commissioning, an immediate increase was observed in catalyst activity.
10
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Date of month Source A shutdown
Source A startup
Source B+C Source A+B+C
Source A+B 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 12 14 16 18 20 22 24 26 28 Catalyst activit y, t ons PP /k g catalyst
FIG. 4. Effect of untreated propylene source on catalyst activity.
FIG. 5. Effect of CO in propylene on catalyst activity.
CATALYST NEWS
NEW STEP-OUT CATALYST FOR ULSD AND HYDROCRACKER PRETREAT
Haldor Topsøe has announced an improved catalyst prepa- ration technology. In hydrocracking pretreatment and high- pressure ULSD services, the catalyst exhibits 40% higher ac- tivity than its predecessor. The higher activity can be used to:
• Achieve longer cycles at the same feed rate • Process tougher feeds
• Increase conversion to achieve lower product sulfur • Increase throughput.
The technology offers an improved production technique for hydroprocessing catalysts. It combines previous technol- ogy with a catalyst preparation step developed by Topsøe’s research department. The combined effect from merging the two technologies has led to a metal slab structure that is characterized by an optimal interaction between active metal structures and the catalyst carrier. As researchers from Topsøe demonstrated in the 1980s, the activity of Type II sites is very strongly influenced by this interaction. The technology affects
the way in which the metal slabs are bound to the carrier, re- sulting in the activity of both the direct sites and the hydroge- nation sites being increased significantly. These new catalysts exhibit high stability with the added benefit of a step change in hydrodesulfurization and hydrodenitrogenation activity.
NEW CATALYSTS CAN HELP AUTOMAKERS MEET CARB LEV III EMISSION REGULATIONS
The California Office of Administrative Law recently ap- proved the more stringent LEV III automotive emissions regu- lations for new passenger vehicles proposed by the California Air Resources Board (CARB). BASF’s direct ozone reduction catalyst systems can help automakers meet these increasingly strict LEV III low-emission vehicle regulations.
When applied to heat exchange surfaces, such as car radia- tors, the BASF system effectively turns them into “smog eat- ers.” The catalyst reduces ground-level ozone in the air that passes over coated surfaces by converting ozone molecules into oxygen molecules instantly upon contact.
HYDROCARBON PROCESSING | CATALYST 2013 C–79
CATALYST
As shown in FIG. 8, CO at the outlet of the bed decreased from approximately 120 ppb to below 20 ppb. A quick analysis based on the two month operation revealed a possible return on investment in less than a year.
Keep it clean. To realize full activity from polymerization cata- lysts, feed streams need to be as clean as possible from all con- taminants and catalyst poisons. A very low level of even a single catalyst poison can reduce catalyst activity drastically. In line with the “keep it clean” philosophy, the feed treatment unit must be carefully selected to treat all possible contaminants. The money invested can give a quick return and the payback period can be completed in as little as six to nine months.
HANIF POORKAR is a senior process engineer for Tasnee in Al-Jubail, Saudi Arabia, where he has been employed for more than eight years. He has mainly worked with different polypropylene process technologies throughout his 16 year career. He holds a degree in petrochemical engineering from Dr. Babasaheb
Ambedkar Technological University in Lonere, India, and an MBA degree from Karnataka University in India.
HAMAD AL-SHBRAIN is the polymer process engineering manager for Tasnee in Al-Jubail, Saudi Arabia. He is a chemical engineering graduate with more than 16 years of experience.
SAAD AL-HARBI is an operations manager at Tasnee in Al-Jubail, Saudi Arabia. He is a chemical engineering graduate and has worked for Tasnee for more than 11 years.
ABDULLAH AL-SAEED is a chemical engineering graduate from King Saud University in Saudi Arabia. He currently works as an operations manager for Tasnee in Al-Jubail, Saudi Arabia.
FIG. 6. Relationship between CO and catalyst activity in a commercial reactor. Current 50-200 wt ppb CO Molecular sieve Molecular sieve CO removal catalyst < 20 wt ppb CO Proposed
FIG. 7. Present and proposed scheme for using existing bed with two types of material.
Catalyst yield Inlet CO ppm Outlet CO ppm
Bed taken online
Improved catalyst mileage
0 3/21/2012 3/22/2012 3/22/2012 3/22/2012 3/22/2012 3/22/2012 3/23/2012 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 5 10 15 20 25
FIG. 8. Catalyst activity before and after mixed bed commissioning.
“This is the first commercial product that destroys harmful, ground-level ozone already in the air,” said Nick Leclerc, prod- uct manager for BASF Corp. “The California Air Resources Board recognizes it as an effective ozone-reduction strategy and offers credits toward LEV III certification for car makers using the technology.”
Over three million vehicles are using this technology.
GRACE ACQUIRES NOBLESTAR CATALYSTS ASSETS
W. R. Grace has completed its acquisition of the assets of Noblestar Catalysts, a Qingdao, China-based manufacturer of fluid catalytic cracking catalysts, catalyst intermediates and re- lated products used in the petroleum refining industry.
“Qingdao is a leading economic center in China,” said Qingdao Bureau of Commerce Vice Director General Cong Yan during a ribbon cutting ceremony. “We welcome foreign investment, especially from companies like Grace, which can help develop our fast-growing petrochemical industry while also acknowledging environmental and safety concerns.”
“The successful acquisition of Noblestar’s assets in Qingd- ao is another milestone in Grace’s long relationship with Chi- na,” said Grace’s CEO Fred Festa. “Our goal is for customers to look to Grace for innovative technology and industry-leading technical service, as well as a globally integrated manufactur- ing network that aligns with the world’s demand.”
Grace expects to make additional investments at the Qing- dao site for environmental, safety and manufacturing upgrades. “We have been happy and proud to be a business partner of Grace’s refining technologies business for years and we are excited to continue a business relationship with Grace in the future,” said Chao Cui, CEO of Noblestar Catalysts.
Grace first established a presence in China when it founded Grace China Ltd. in 1986 as one of the first foreign-owned companies to do business in the country, through its can seal- ants plant in Shanghai. Currently, Grace operates five manu- facturing facilities, three sales offices and two technical service centers in mainland China, including its Asia-Pacific regional headquarters in Shanghai.