Anne K. Rhodes
Refining/Petrochemical Editor
In November and December 1991, Beta Raffinerie-gesellschaft Wilhelmshaven MBH restarted the mothballed refinery at Wilhelmshaven, Germany. The refinery - formerly operated by Mobil Oil AG - had been shut down in May 1985.
Oil & Gas Journal described the original grassroots refinery in 1976, just after start-up.1 The refurbished refinery is one of the largest and, in a sense, newest European refineries. It is also sophisticated enough to produce high-grade, low-sulfur fuels and meet stringent emissions specifications, even when processing high-sulfur crudes.
Located on Jade Bay in northern Germany near Wilhelmshaven (see map), the Beta facility is the only refinery in Germany on a deepwater port.
Through the deep-water channel, crude oil tankers with a draught as deep as 16 m (52 ft) also have direct access to the refinery from the North Sea.
End products are transported via tanker, rail, and truck to their final markets.
RECOMMISSIONING
In 1990, Beta was anticipating the refining supply demand balance to become more favorable, both globally and, in particular, in Northern Germany. Northern Germany was, at the time, importing as much as 600,000 b/d of refined products.
Beta contracted to purchase the refinery in April 1990 and completed the purchase in November of that year. At the time of purchase, the refinery was of only intermediate complexity, with a complexity factor of 7.64. The 160,000 b/d Wilhelmshaven plant was, however, modern, well-equipped, and most importantly, geared for large-scale operations.1
Refurbishment and recommissioning took only about 1 year. In view of the complexity of the task and the amount of debottlenecking and reconfiguring required, the project required relatively little time.
The primary steps were: 0 Detailed visual/ultrasonic inspection
- Reassembly or replacement of all pumps
- Replacement of much of the piping and installment of new piping to improve tank farm flexibility
- Disassembly and reassembly of all jetty booms and dredging of the jetty
- Sandblasting and relining of all tanks, installation of double seals, and replacement of various tank bottoms
- Conversion or upgrading of several tanks to other uses
- Strengthening of LPG spheres and covering them with concrete casements
- Reactivating the Foxboro control system for start-up (The system is now being replaced with another system.)
- Complete overhauling of all process units, replacement of drawers in towers, rotors, and other equipment, and debottlenecking of process units to achieve higher throughputs (Table 1)
- Upgrading of all furnaces and heaters, as required, and re-equipping them with low-NOx burners
- Installation of a stack-emissions measurement control system
- Removal of all asbestos gaskets and replacing them with nonasbestos gaskets
- Renewal of rail and truck-loading automation and installation of bottom-loading and vapor-recovery systems.
Beta president J. A. van Weelden attributes the company's rapid progress to five factors:
- The detailed preinspection
- The involvement of many personnel formerly with Mobil and the Badger Co. - the main contractor for the refinery construction
- The close working relationship with German authorities in consideration of the stringency of their requirements
- The lack of weather problems
- Good management.
OBSTACLES
No major obstacles were encountered during refurbishment and recommissioning. Replacement of more equipment than was originally hoped, however, was necessary. In particular, various equipment flaws uncovered during hydraulic testing necessitated the short-notice replacement of much hardware.
This testing, using glycol, started in January under freezing conditions. The first test showed the equipment to be sound, but a second test in June showed severe leakage of the air coolers. Flaws were found in the 24 overhead air coolers, forcing the replacement of about 2,000 tubes per cooler.
A second example of the discovery of these flaws was the condensate system, where full replacement of the piping was necessary.
Authority requirements were also extremely stringent and occasionally unanticipated. For example, concrete casements were required for the LPG spheres, to provide fire insulation with a 90-min rating.
In general, environmental standards-including emissions limits-were set at levels that exceed current legal requirements. None of these points, however, presented a major impediment to the project.
GERMAN MARKET
The recommissioning has greatly reduced Germany's refined-product demand and altered its import/export balance.
Northern Germany is still a net importer of refined products, although not to as great an extent as before. Area marketers have an additional primary supply source at the Wilhelmshaven racks, which are the most modern in the region and well-served by road and rail.
Beta products are also made available at other regional locations. This availability provides long-term supply security to northern Germany, which was previously dependent on the terminals and two small refineries at the shallow-water port of Hamburg.
The Wilhelmshaven refinery also exports products, particularly specialty grades and cracker and lube feedstocks. For example, atmospheric residue from the refinery is sold in Germany and the eastern U.S.
In general, there are few suppliers of these products, and markets for them are still tight, even with the addition of products from Wilhelmshaven.
CRUDE OIL
The refinery was originally designed to accommodate high-sulfur and high-acid crudes. (The design parameters were based on Saudi and Nigerian grades.) The deep-water jetty can accept very large crude carriers so that even the most distant crude sources are potentially attractive economically. The long-term crude supply flexibility, therefore, is enormous.
The refinery's desulfurization facilities are ample for even a fully sour crude slate, given that the atmospheric residue is sold.
And Beta's upgrading plans for the refinery are being developed specifically to preserve the refinery's ability to process crudes with high levels of sulfur and metals.
The refinery now processes predominantly North Sea and African crudes, but this is, of course, subject to continuous review.
PROCESSING SCHEME
Fig. 1 is a detailed flow diagram of the refinery. Oil is unloaded at the deepwater jetty and pumped to storage tanks, where it settles for several days.
It is cleaned and desalted then pumped through heat exchangers and a furnace before entering the distillation tower.
The distillation unit separates five raw product streams: naphtha, kerosine, light gas oil, heavy gas oil, and reduced crude or residue.
Table 2 shows current product yields. Although these yields are obviously a function of the crude slate, the addition of a Mobil Distillate Dewaxer (shown as the hydrodewaxer in the flow diagram) in 1980 changed refinery yield patterns substantially.
This catalytic process - described in a 1980 OGJ article - desulfurizes gas oil and converts wax molecules to gasoline. 2 The unit was de-bottlenecked and recommissioned in 1991. The process upgrades heavy atmospheric gas oils to produce LPG, 90-RON gasoline, and a heavy, but very-low pour point and cloud point, distillate.
Another change in the refinery flow scheme is the installation of another dehexanizer between the pre-treater and the catalytic reformer.
This addition allows finer optimization of reformer feed and reduces the load on the gas plant.
A unique feature of the Wilhelmshaven refinery is its unusual crude oil distillation column. The column can process two trains of crude oil simultaneously while keeping the bottoms separate.1
This unit also has the distinction of being able to segregate a wide range of distillation cuts, extending as deep as 450 C. (842 F.), or even higher, depending on stability.
PRODUCTS
The refinery currently produces 0.2%-sulfur diesel and heating oil for the German market.
It is capable, says van Weelden, of meeting a 0.05%-sulfur specification on its entire output, even with a sour crude slate.
This ability is sure to make the Wilhelmshaven plant one of the more profitable refineries in the tough years ahead.
Another advantage the refinery has is that, although it has the ability, it does not produce heavy fuel oil or bunker-grade fuel oil. As previously mentioned, its atmospheric residue is sold as a feedstock.
With the North Sea and African crude slate, this stream typically has sulfur levels of 0.3-0.7%.
The refinery is also able to produce 100% "Super Plus" unleaded gasoline (98 RON, 88 MON). In practice, though, Beta blends to produce some Eurograde, regular, and leaded gasolines, in accordance with market demands.
(Eurograde is an unleaded 95 RON/85 MON blend that must be marketed in European Community countries, according to EC directive 85/210/EEC.)
Typical Super Plus summer gasoline specifications are shown in Table 3.
In the process of refurbishing the refinery, some storage tanks have changed usages and some additional tanks have been constructed.
Current storage capacities are listed in table 4.
OPERATING COSTS
The debottlenecking of the process units and various energy-saving projects have had a dramatic effect on fixed and variable costs, Van Weelden believes Beta's operating costs are similar, in absolute terms, to local competing refineries operating at one third of Beta's scale.
When measured in dollars per barrel, this gives Beta a relative unit cost advantage.
ENVIRONMENTAL PEGS
During the recommissioning process, substantial investments were made in upgrading the environmental performance of what was already a very modern plant. The result is that the refinery is now an exceptionally clean and environmentally responsible facility (Fig. 2).
Germany's environmental regulations are already the toughest in the European Economic Community. And Beta's existing limits are set for the next 9 years of its permit.
German law limits SO2 emissions from existing plants to 1,200 mg/cu m. Beta's SO2 emissions, however, are limited further to 600 mg/cu m at present and 533 mg/cu m from 1996 onward, by agreement with German authorities.
The refinery's NOx emissions are limited to 400 mg/cu m on the East stack, which serves the smaller generation facility. Emissions from the West stack, which serves the bulk of the refinery's generation facilities, are limited to 150 mg/cu M.
The West stack is also limited to 50 mg/cu m of dust and 175 mg/cu m of carbon monoxide.
Emissions of heavy metals are limited to 2 mg/cu m, in total.
It should be noted that Beta reports that the refinery currently operates comfortably below even these strict limits.
In terms of product specifications, the refinery is already prepared to produce 100% premium unleaded gasoline and 100% 0.05% sulfur diesel.
In light of Beta's ability to meet these emissions and fuels requirements, the Wilhelmshaven refinery is probably better equipped than most to comply with changing environmental requirements in the coming years.
FUTURE
Other plans for the Beta refinery include further residual upgrading investment and isomerization and cogeneration facilities, which will be fueled by vacuum residue.
A long-term project to build a gasification plant and associated power-generation facilities at Wilhelmshaven is also in the works.
REFERENCES
- Aalund, Leo R., "New German plant has strategic site," OGJ, Nov. 29, 1976, p. 47.
- Donnelly, S.P., and Green, J.R., "Catalytic dewaxing process improved," OGJ, Oct. 27, 1980, p. 77.
Copyright 1993 Oil & Gas Journal. All Rights Reserved.
