Latest generation of high selectivity EO catalyst promises industry leading yields

12 Shell Chemicals Magazine Autumn/Winter 2010 CATALYSTS

SELECTIVEREASONINGCatalysts are crucial to speeding up chemical reactions,improving yields and delivering competitive petrochemicalmanufacturing. The discovery and commercialisation ofa new high selectivity catalyst has provided anotherstep-out improvement in Shell’s long history of innovationand development in ethylene oxide (EO) catalyst andprocess technology. It offers producers worldwide thechance of achieving the highest yields.

It may have seemed like just another day in the

office - or rather the laboratory - for Marek Matusz,

a Senior Research Chemist with Shell Global

Solutions, but something in the results of the latest

batch of catalyst screening tests caught his eye.

Although not obvious at the time, the 20-year

veteran of catalysis research and his team were

about to make the most significant breakthrough

of their careers.

The samples under analysis that day back in late

2004 were the latest among hundreds of catalyst

formulations being continuously screened at Shell’s

Westhollow Technology Centre (WTC) near

Houston. But Matusz and his technicians had hit

upon a formula for the complex combination of

elements that make up catalysts that would deliver

a step-out improvement in yields for EO production.

“We were running routine tests and caught

a glimpse of something in the data but weren’t

exactly sure what we had found at first,” he says.

“It took a lot of further tests and analysis to isolate

and interpret the results, and then to convince

ourselves they were real and repeatable.”

Their discovery of a new high selectivity catalyst,

S-888 as it was later called, promised a significant

improvement over all existing catalyst/process

technology combinations. As remarkable as the

selectivity being achieved in the laboratory with

the newly identified catalyst, however, was the

Shell Chemicals Magazine Autumn/Winter 2010 13

speed at which Matusz’s initial discovery was

subsequently developed.

Scaling up the new catalyst from the laboratory

to a full commercial offering was one of the

biggest challenges of the development process.

Once the decision to commercialise S-888 was

taken, a wider team of experts in catalyst testing,

manufacturing and operational support swung

into action. Close interaction between these

supporting disciplines was key to the speedy

commercial implementation.

Within just a few years – the blink of an eye

in catalyst R&D terms – production of S-888 had

been scaled up, commercialised and the new

catalyst loaded into five Shell-owned EO plants

around the world. It has since achieved industry-

leading selectivity rates, which has an enormous

impact on the overall economics of EO production.

Catalyst selectivity determines how much EO is

produced versus ethylene feedstock consumed.

The ethylene feed accounts for around 80% of

the total cost to produce one tonne of EO – the

catalyst no more than 5%.

“When you’re burning a high value feed you try

to get the highest selectivity, hence product yield,

with the least amount of byproduct,” explains

Scott Baker, Shell Global Solutions Technical

Excellence Manager for EO Catalysts.

“To put this into perspective a one percentage

point increase in selectivity for a world scale EO

plant can be worth $2-3 million per year in

value. An improvement of two or three percent,

as S-888 can deliver, becomes a major

competitive advantage, especially given that

significant increases in yield are becoming

harder and harder to find.”

He adds that an efficient catalyst also helps

to reduce plant CO2 emissions as less of the

greenhouse gas is produced as a byproduct.

The S-888 high selectivity catalyst is now an

integral part of the package of proprietary EO

process technology that Shell licenses to other

EO producers around the world.

“Income generated by technology licensing

is critical for funding ongoing R&D efforts and

maintaining our market leading position,” says

Baker. “Shell’s own plants will always be the

first to benefit from any future breakthroughs.”

Shell has been developing EO catalysts and

process technology for more than 50 years

[see below]. The WTC labs use enhanced

Left: Marek Matusz, whose team made the initialdiscovery that led to the development of the latestgeneration of high selectivity EO catalyst.

MASTERS OF THE EO PROCESS

Shell has pioneered many of theadvances in ethylene oxide processtechnology since 1958. The ShellMASTER Process for convertingethylene to ethylene oxide has beenproven over many years operation,in both Shell plants and those ofco-producers across the world.

It has been developed to maximisethe performance of high selectivitycatalysts where Shell, through itsaffiliate CRI Catalyst Company, hasalso led the industry.

The selectivity of EO catalysts hadgrown incrementally until the mid1980s when Shell technologistsconfounded the then current scientificthinking by breaking the 85%selectivity barrier.

That discovery opened the way tothe development of a new breed ofhigh selectivity catalysts and evenhigher rates of conversion, culminatingin the latest S-888 generation.

Today, over 30% of the world’s EO isproduced in Shell-licensed and designedplants, and around 50% of global EOproduction uses Shell/CRI catalysts.

14 Shell Chemicals Magazine Autumn/Winter 2010 CATALYSTS

For more information on catalysts visit:www.cricatalyst.com

interest to operators of some of the newest plants

coming onstream in the Middle East and Asia,

due to the favourable operating conditions these

installations can achieve.

“Catalyst selection is usually a function of

process constraints,” explains Baker. “Some

facilities, especially older assets, may not be able

to achieve the optimum reactor conditions needed

for high selectivity. Modern plants are designed

with process conditions that enable them to

extract full value from S-888.”

PRODUCTIVITY GAINSHe says there are also some trade-offs in catalyst

selection. “Higher selectivity catalysts typically

have a shorter life-span, but for most producers

the productivity gains far outweigh the shorter

operating life. The life of S-888 is expected to

be up to four years in modern plants depending

on how hard the catalyst is working and other

process factors.”

Baker’s team also provide complete technical

service support to both Shell plants and catalyst

customers. “A change of catalyst is a not just a

significant upfront investment, it can also be a big

expense in terms of plant downtime and getting

the unit up to maximum productivity,” he says.

“One of S-888’s advantages is that it is simple

to start up and achieves high selectivity very quickly.

“We work closely with customers over the life

of the catalyst, from supporting the installation

and startup processes to providing ongoing

technical services for optimising its performance.

We can offer a prediction of what performance

to expect from a catalyst and, as performance

declines, suggest modifications to operating

conditions to stretch it out as long as possible.

“S-888 has proved to be robust and able to

handle variable process conditions, while its

slow rate of decline adds to its performance

advantage.”

While S-888 has raised the bar in EO catalyst

performance, the pursuit of ever higher levels of

selectivity continues. “We never stop looking for

the next incremental improvement because the

potential impact of catalyst performance is so

great,” says Matusz. “There’s always room for

improvement in the existing technology and,

who knows, maybe another big breakthrough

is around the corner.”

experimentation techniques, micro- and nano-scale

reactors and several pilot plants to carry out

multiple simultaneous testing of potential catalyst

preparations.

Enhanced Experimentation provides the ability

to accelerate research and development projects,

allowing higher performance testing efficiency,

which translates to shorter development phase

for new products and accelerated time to market.

OPTIMISED FORMULATIONIt was a key enabler in the commercialisation

of the S-888 catalyst, reducing the testing time

required to carry out screening experiments to

optimise the formulation, resolve manufacturing

issues and establish an intellectual property

position to less than six months, compared to

an estimated 12-18 months using convention

R&D processes.

Achieving a dramatic reduction in development

time is especially valuable given the complexity of

catalyst development. “Identifying a breakthrough

new catalyst is not quite like finding a needle in

a haystack but it’s not far off,” says Matusz.

“It can translate into thousands of experiments,

using different combinations and ratios of elements.

“Our history and experience in the field of

catalytic principles, combined with enhanced

experimentation testing, helps us to focus on

the formulas most likely to bring results and in

the shortest possible time.”

There are now nearly 120 EO producers

worldwide. In addition to Shell plants, the S-888

catalyst has been sold to nine third party plants

during 2010 and there are 14 sales lined up

for 2011. The S-888 generation is of particular

The S-888 generation of high selectivity catalystsis produced at the Shell/CRI Catalyst Companymanufacturing facility at Martinez, California, USA.

A PERCENTAGE POINTINCREASE IN SELECTIVITYFOR A WORLD SCALE EOPLANT CAN BE WORTHAS MUCH AS $2-3 MILLIONPER YEAR IN VALUE.

“

“Scott Baker, Shell Global Solutions TechnicalExcellence Manager for EO Catalysts.