Our advanced hydroprocessing technologies provide today’s base stock manufacturers with maximum value through exceptional process performance for yield, run length and durability and outstanding product qualities.
MSDW/ MAXSAT / MWI
The turn of the century marked a remarkable turning point in the lubes basestock manufacturing industry — no significant API Group I capacity has been added worldwide since then. In fact, Group I capacity has been steadily shut in. Conversely, Group II and Group III manufacturing capacity has been added, satisfying a slowly but steadily growing capacity demand now approaching 800 kBd. In both North America and Europe, the number of plants producing lube basestocks is now about a third of what it was in the early ’70s, but the average size of the plants increased by threefold.
Two key reasons may be attributed to this evolution. The first is the increase in overall basestock quality spurred by the automotive and transportation industry in its quest for higher fuel economy and lower overall emissions. The second is the emergence since the mid ’90s of more advanced hydroprocessing routes to the production of lubricant basestocks, especially for engine oil lubrication applications.
A typical configuration of a modern, all-catalytic plant is depicted in Figure A. The Hydrocracker and the MSDW/MAXSAT unit are operated in three modes, or “blocks”: a Light, a Heavy, and a DAO/ Bright Stock block. Each block produces one main basestock product and may produce one or more additional lube products depending on the specific configuration. This scheme is typical of a lubes hydrocracker, where the hydrocracker operation is adjusted primarily to maximize lube production. There are also “hybrid” schemes, for example, where the hydrocracker is operated on a wide VGO cut feed, primarily for fuels production, with the MSDW unit operated either on a wide-cut UCO (UnConverted Oil) or fractionated UCO cuts.
However, the technology flexibility is such that a refiner can choose to operate the entire train by processing one single, wider-cut feed. This is commonly referred to as “broad cut” operation, where all the desired lube basestocks are fractionated at the very end of the process. Each of the two configurations has advantages and disadvantages, as summarized in the tables below:
MSDW / MAXSAT technology advantage
High-performance catalytic isomerization dewaxing is the preferred route for the production of the high-quality engine oil basestocks demanded by today’s vehicles. MSDW/MAXSAT is EMRE’s premier lube catalytic dewaxing and hydrofinishing technology. A typical process configuration is a two-reactor system. The first reactor primarily transforms the linear paraffins (wax) into high-quality lube products (isoparaffins) and accomplishes some saturation of the aromatic compounds. The second reactor deeply saturates aromatics to impart outstanding color and stability.
A typical size MSDW/MAXSAT unit is between 10 and 20 kBd. This proven technology is capable of processing a very wide range of feedstocks, varying from hydrotreated or hydrocracked VGOs and DAOs to hydrotreated raffinates and slack waxes. Typical products are basestocks in the API Group II to III+ range, with viscosity grades as low as 2 and as high as 25 cSt at 100°C, depending on the feed.
The Catalyst Makes All the Difference
At the heart of the process is a system of proprietary shape-selective catalysts containing zeolites and small amounts of noble metals. They are specifically designed to isomerize n-paraffins and saturate aromatics with maximum selectivity to lubes and minimal cracking to fuels.
These catalysts, manufactured at our own facilities, display superior activity and selectivity and unsurpassed tolerance to nitrogen, sulfur, and aromatic contaminants in the feed. Even a temporary degradation in feed quality, which might irreversibly poison other catalysts, will require only a temporary increase in operating temperature with minimal impact on aging and virtually no impact on product yield.
In fact, to date none of the more than 20 commercial units operating with MSDW catalyst has changed the catalyst fill due to aging, poor performance due to feed contamination, refinery upsets or reaching end of cycle. Two of the units have operated for more than 12 years, with one still using the original catalyst fill.
Performance You Can Trust
- Yield and selectivity
- Activity and run length
- Robustness and durability
Exceptional Product Quality
- Low temperature properties
- Water white color
To put the true value of the yield advantage of the MSDW catalyst system in context, consider this: for an average MSDW unit, at current product prices, a difference of one percent in yield of basestock product is worth between $2 million and $4 million per year over producing diesel fuel, or about $7 million to $8 million per year in revenues.
Maximizing basestock product yield is obviously important. But when you operate an MSDW unit, even the by-product is valuable. This is because the majority of the conversion product from the MSDW catalyst system is diesel fuel with essentially no sulfur, an excellent cetane number, and outstanding low-temperature properties. This product is often blended with other distillates to actually increase the quality of the diesel pool or supplement sources of arctic-grade diesel!
Energy lives here
In today’s world, standing still corresponds to stepping backward. At EMRE we have active R&D to continue to boost yield, further improve tolerance to heteroatom contaminants, and broaden the range of acceptable feedstocks. We are now on our third generation of the MSDW catalyst system, with better activity, selectivity and polar tolerance than the original catalyst we used in our first deployment in 1997.
ExxonMobil, its heritage companies Exxon and Mobil, and its affiliates worldwide have literally generations of experience in lubes manufacturing. ExxonMobil operated and often pioneered the development of lube basestock manufacturing throughout the world.
- Mobil’s MLDW catalytic dewaxing technology using ZSM-5 zeolite-based catalyst was deployed in 1979 at the Adelaide, Australia Refinery.
- MSDW technology was commercialized at the Jurong Refinery in Singapore in 1997.
- Raffinate HydroConversion (RHC) was commercialized in Exxon’s Baytown Refinery in 1999.
- MWI (Mobil Wax Isomerization) was deployed at the Fawley, UK Refinery in 2003.
Raffinate Hydrotreating (RHT) / Raffinate Hydroconversion (RHC)
A cost-effective path to moving your solvent lube unit into production of high quality group II / II+ /III lubes. ExxonMobil’s Raffinate Hydrotreating (RHT) and Raffinate Hydroconversion (RHC) technologies are commercially proven processes that can transform a Group I solvent lube plant into a Group II/II+/III advanced and flexible manufacturing facility.
The Group I share of lube demand continues to decline. Growing demand for Group II and Group III base stocks for today’s high-performance engine oil formulations is driving most new lube production toward Group II/III lubricants and pressuring existing Group I production. Solvent technology alone cannot meet the stringent requirements of the Group II/III base stocks. These higher quality products require some catalytic processing to achieve the high saturates content and very low sulfur of the Group II/III specifications. However, a full catalytic lube train may be a large investment.
RHT is ideally suited to provide a cost-effective solution for operators that want to convert a solvent plant from Group I to Group II/II+/III base stock production while retaining the existing solvent extraction plant. The RHT products are of the proper quality to be further processed with advanced Catalytic Dewaxing, such as ExxonMobil’s MSDWTM process. The flexibility of the RHT process allows the operator to vary the product Viscosity Index thus effectively choosing which base stock Group to produce. RHT/MSDW can be applied to the full base stock slate, thus eliminating the need for the solvent dewaxer, or to selected grades only. In this second case, where some Group I base stocks continue to be produced via the conventional solvent-based route, overall lube production may even be increased through judicious optimization of the entire lube complex.
Manufacturers who want to upgrade their existing Group I plant to produce Group II / II+ base stocks for selected grades, while maintaining Group I production for others, should also consider the RHC technology. RHC processes raffinates from the existing solvent extraction into Group II+ oils that are then solvent dewaxed in the existing dewaxer. Group I lubes are processed only on the solvent extraction unit. The 1999 streaming of the Baytown RHC unit proved that an existing solvent plant can be transformed into a flexible facility to produce Group I products and Group II/II+ base stocks as well, at moderate cost. The RHC feeds can be under-extracted, thus expanding the solvent extraction unit capacity and providing maximum lube recovery from the combined extraction/RHC steps.
RHT and RHC thus offer a high-value process solution to expanding both the product range and the operating flexibility of an existing solvent-based lube plant. This raises the production value of the existing facilities while expanding the product quality capabilities and maximizing existing equipment use.
Leverage existing refinery infrastructure and process capacity
- May result in significantly lower CAPEX investment than a new grass roots all-catalytic plant
- Existing vacuum distillation equipment is retained
- Existing solvent extraction is retained for feed preparation
- Optimizing severity between solvent extraction and RHC maximizes total lube production
- Existing solvent dewaxing can be retained, thus preserving wax by-product
- Well understood and widely deployed catalytic hydroprocessing technology
- Commercially available catalyst choices
- Robust design accommodates a wide range of crudes, VDU and extraction operations
- Stable operation with long cycle life
- Adjust to saturates and VI needs by modifying Solvent Extraction and, or RHC severity
- Adjust to NOACK needs with processing and back-end fractionation
- Process full range of viscosity grades, or only selected ones to maximize value to refinery
MLDW™ Catalytic Lube Dewaxing
ExxonMobil’s MLDW™ catalytic lubes dewaxing process can help operators dramatically reduce base stock production cost.
Deployed at the Adelaide refinery in 1979, and in reliable service in many lube plants ever since, MLDW can operate where other catalysts would fail. MLDW turns even high nitrogen and sulfur solvent-extracted raffinates, or propane deasphalted oils, into conventional or ultra-low-pour point base stocks (- 40 °C and below). Whether for a revamp or a grassroots application, choose MLDW and see significant savings over solvent dewaxing, including lower utility costs since the need for solvent refrigeration, recovery and recycling is eliminated.
- Very long cycle length
- Better cold-cranking product properties
- Lower capital investment — about half that of solvent dewaxing
- Dramatically lower utility costs
- Boosted yields in heavy stocks
- Vastly lower production costs
- Safer operations — no volatile, toxic organic solvents
- Highly flexible process
A history of success with a proven process
A state-of-the-art, dual-reactor system uses proprietary technology to assure optimal feed distribution. This process utilizes equipment similar to that of middle distillate desulfurization units, and it has been retrofitted into these units. The shape-selective dewaxing catalyst does all the work to crack high pour point paraffins into naphtha and gas. This highly flexible process operates at hydrogen pressures ranging from 400 to 3,000 psig (27 to 200+ bar). In downstream recovery, the lube base oil is separated from hydrogen-rich recycled gas and by-products, primarily naphtha and propane.
One stop shopping
As a major crude refiner, global base oil marketer, strategic researcher and licensor of every aspect of lube technology, ExxonMobil is positioned to add value to its customers’ operations. ExxonMobil can help you monetize your assets and develop a plan for the future.