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Innovation drives new catalyst developments

04.01.2011  |  Letzsch, W.,  The Shaw Group, Houston, Texas

Future challenges in environment and product specifications involve more sophisticated catalyst systems

Keywords: [catalysts] [refining] [petrochemicals]

The catalyst business continues to reflect the trends of the refining and petrochemical businesses it serves. These trends include globalization, consolidation, integration and diversification.

The worldwide refining community is shifting from North America and Western Europe to the Middle East and Pacific Rim. This is a consequence due to the location of major crude reserves and growth markets for refined-oil products. Catalyst suppliers have stepped up their presence in Asia-Pacific, and they are facing a new competitor in Sinopec. The Chinese are producing most of the standard refining catalysts for their own use and have started exporting some catalysts to neighboring countries.

Fluid catalytic cracking (FCC) catalysts made in China are now being used in several catalytic cracking units in the US, and a sales office has been opened in Texas. China is doing extensive research in catalysis for refining and petrochemical processes, and this is reflected in their many contributions to the technical literature in recent years. At some American Chemistry Society (ACS) meetings, conference papers presented by Chinese companies make up more than half of the papers in particular sessions. In due time, China will actively compete in the full spectrum of refining and petrochemical catalysts.

Rare earth challenges.

China currently controls about 97% of the rare earth market; this nation cornered the market through pricing strategies that made all other sources uneconomical. Recently, there have been large price hikes for rare earth materials, and China has capped exports. Rare earth elements are used in a variety of strategic applications and have been used for years as a stabilizer for fluid cracking catalysts. This has catalyst suppliers both scrambling to secure supplies and to find ways to minimize the rare earth components in catalyst structures and makeup. Previously closed mines around the world will be reopened in the next few years, and some type of price floor will need to be established to ensure the mine’s on-going operation.

A global business.

The evolution of the catalyst business is a natural phenomenon in the world of commerce. In the beginning, catalyst plants served indigenous markets and survived due to limited competition and protective trade laws. The elimination of trade barriers and more sophisticated technologies have caused many small plants to shut down. Those remaining have been increased in size, thus taking advantage of the economies of scale. This poses challenges to the catalyst manufacturer since clients want products customized to their specific applications.

When the industry that buys your product is being squeezed economically, all of its suppliers will feel the pinch. This prompts all companies to back integrate into raw materials and to find ways to lower costs while meeting ever more stringent environmental regulations for air and water emissions and solids disposal. Energy usage is a major cost to hydrocarbon processing industry (HPI) plants. The drop in US natural gas prices makes all of the US catalyst works more competitive. The depreciation of the US dollar compared to other currencies causes catalysts made in North America to be more financially attractive. Advanced automation and instrumentation can help reduce costs and improve product quality.

Market integration.

With refineries growing in size and complexity and now increasingly being integrated with petrochemicals, it is natural that catalyst suppliers would want to serve both markets. Hydrogen plants are being installed in more refineries as the need for hydroprocessing of all refined products processed in the refinery is required to meet new product sulfur specifications. Other petrochemical catalysts, such as those used to make polyethylene, polypropylene and styrene, are used in these large, integrated refining-petrochemical complexes. Some of the major catalyst suppliers currently serve both segments. Expect more moves in the future in this direction.

Environment.

Another area of market integration is combining refining with environmental catalysts. New regulations are reducing the level of all contaminants in the water and air as well as in refined products produced. Catalysts that reduce the amount of sulfur in flue gases or exhaust streams or in the various products have a lot in common with refinery catalysts. They tend to share in the same base materials such as silica gels, aluminas or combinations thereof. By increasing the volumes of these materials, the catalyst supplier can put in a large-scale plant to make base materials rather than having to purchase from an outside source. Similar products can be used as bases for treating transportation exhaust gases to remove nitrogen oxides (NOx),carbon monoxide (CO) and hydrocarbons. Metals impregnation techniques are also crucial for many catalyst systems to ensure maximum catalyst performance and to minimize the use of expensive raw materials such as platinum, cobalt, nickel and molybdenum.

Biofuels.

The use of ethanol in gasoline has generally made octane a surplus commodity. More than half of the reformers in the US are operated for hydrogen production rather than for octane. Going to 15% ethanol would put almost every refiner in this category. Refiners are integrating into ethanol facilities, but the impact on the refinery would be very significant. The base blendstocks would have to be very low in vapor pressure (Rvp), and this would impact other refinery processing units. The conversion on the catalytic cracking unit might have to be lowered, isomerization units bypassed and continuous reformers operated for octanes of 90 or less. Hydrocrackers may split their naphtha into fractions, with the heaviest fraction becoming a blendstock.

New processes may be introduced that create high-boiling naphtha that can be used as a gasoline blending stock. Alkylation of single-ring light aromatics may become attractive. Some overcracking of gasoline would possibly be practiced to increase the amount of alkylate in the gasoline pool and amylenes (C5 olefins) could be a much more common alkylation feedstock.

Ethanol usage could grow even further if the current ethanol fuel mandate is left in place and enforced. This would require at least a doubling of the current production, along with the development of new technologies to make the ethanol using cellulosic material. Diesel made from biomass is also being pursued, which will require further processing. This will require processing with diesel streams produced from conventional oil. Hydrotreating will also be used in this service.

The use of ethanol would reduce the amount of oil processed in the US but it will not reduce greenhouse gas (GHG) emissions and could have adverse effects on water usage and storm-water run-off from agricultural lands. These facts could prompt a revision of present laws.

Major trends.

In looking forward, the major trends in crude-oil refining are dieselization and the reduction in fuel-oil usage. Both of these are being addressed by the use of more hydrocracking and bottoms-conversion technologies such as coking, residual catalytic cracking and hydrocracking. Residual desulfurization is sure to increase due to mandated sulfur reductions that will be mandated over the next 10 years. Total catalyst consumption for all of these processes will grow significantly.

Improved refining processes continue to be developed as venders probe every aspect of a particular unit. Fixed-bed reactors used graduated supports made of ceramic material both on the bottom and top of the bed. These were replaced by active-support products that had catalytic activity. Today, the supports not only have activity but may also possess a pore structure to trap and hold contaminants that could cause high pressure drops.

The marketplace is always demanding new products, and suppliers work harder to deliver them. In the area of hydrotreating, the ultra-low-sulfur diesel (ULSD) specifications implied that refiners would need to add additional reactor volume to deal with the most difficult-to-treat molecules. Hydrotreating catalysts had been in use for 40 years and any major breakthroughs seemed unlikely to occur. Use of more sophisticated equipment—in this case a very powerful scanning, tunneling electron microscope—gave researchers a better look at the catalyst surface, and they were able to see what sites needed to be created to enhance the catalyst activity. Application of high-activity hydrotreating catalysts has saved considerable capital and energy since start-of-run temperatures can be reduced.

One of the new FCC catalysts introduced was accidentally discovered. The research program was trying to improve gasoline desulfurization, but a sample prepared that did not show promise for those reactions, was found to have exceptional activity. That provided a lead to the development of a whole new catalyst family.

Whether the innovations are incremental or breakthrough, one thing is sure: they will continue to occur, driven by a very competitive marketplace. Since the catalyst is the heart of most HPI processes, refiners and petrochemical plant operators can expect continued improvements that will increase capacity and product selectivity as well as reduce energy usage. Breakthroughs may even require substantial modifications to existing processes. HP

The author 

 
  Warren S. Letzsch has 43 years of experience in petroleum refining including petroleum catalysts, refining and engineering and design. His positions have included R&D, technical service and sales, which led to senior management positions in sales, marketing and technology development and oversight. He was one of the developers of the Shaw/Axens R2R process. Mr. Letzsch has authored over 80 technical papers and holds eight patents in the field of fluid catalytic cracking. He was the FCC/DCC program manager at Stone & Webster/Shaw for 10 years and is now a senior refining consultant for Shaw, as well as a private consultant to the refining industry. 




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