| | 
Refineries break down mineral oil and process its components for further use. The refinery’s technology then also itself has to be processedat regular intervals. In shutdown maintenance such as this, cleaners,greases, bonded coatings and assembly pastes play a role on practically every handle, as illustrated by the current example of the servicework at the OMV Schwechat refinery near Vienna, Austria.
At the otherwise peaceful site of the OMV Schwechat refinery, people and machines are moving around everywhere. It’s time for the routine planned shutdown, servicing the technical plant. This means to stop activities asspecified in the Pressurised Equipment Monitoring Ordinance, subjecting the plant technology to a comprehensive safety inspection, and general inspection and preventative maintenance work.
The maximumamount of work must be done in a very short time, which is only possible with external help. In addition to the regular workforce, some 1700people from service-providers and service personnel of the componentmanufacturers are moving around the site. This thorough check-up coststhe company around 32 million €. At the same time, OMV is investing another 200 million € in increasing the capacity of the ethylene plantfrom 650,000 to 900,000 tonnes annually with an additional 800 external specialists are actively involved in this. A total of 2500 people must make the complex plant technology ready for production within a fewweeks.
At first glance it’s astounding that in view of such an investment volume, thought is given to the use of lubricants and assembly pastes as these consumables are normally regarded as being of low importance. But OMV looks intentionally at these products as being most definitely important time management components. The entire plant infrastructure must be inspected, serviced and if necessary repaired. Engineer Robert Pappenberger, head of Planning & Control and the shutdown supervisor, knows the specific figures by heart: 2 furnaces, 56columns, 406 heat exchangers, 388 containers, 2800 valves, 1300 safetyvalves and 2400 measuring and control devices must be serviced. “In addition there are the necessary repairs to the pipelines, and investments that can only be made when the plant is shut down”.
For theshutdown, the refinery’s external service-providers assume responsibility for over 95% of the work. Pappenberger explains that “as its coretasks, maintenance includes technical responsibility, long-term planning and also organisational and monitoring functions”. Of course, besides setting the duration of the shutdown, from a safety and economy point of view this also includes incorporating knowledge gained from previous shutdowns with regard to safety, the length of the shutdown, thework sequence and costs, as well as the pre-planning of additional activities for future shutdowns.
How problem-free the planned work sequences then actually run during the short shutdowns depends on,among other things, the time taken for the assembly/disassembly of supply lines, apparatus and machines and the measuring and control devices. Perfect preparation of surfaces and use of suitable bonded coatingor assembly paste ensures the reliability of the connection and makesits disassembly easier later on. At the Schwechat refinery, productsfrom the OKS Company of Munich, Germany are used for a number of applications. OKS, a subsidiary of Freudenberg Chemical Specialities KG, develops produces and markets worldwide special lubricants as well as cleaning and corrosion-protection products for all types of service andmaintenance work. A brief glance into the world of tribology clearly shows the importance of such products in everyday work. Besides theprimary demand placed on the lubricant –maximum power transfer combined with a minimum of friction and minimum wear – it is often necessaryto fulfil various secondary properties such as water resistance, chemical resistance compatibility with plastics or corrosion protection.
•Mineral oils, synthetic hydrocarbons, silicone oils, polyglycols,ester or similar synthetic liquids are used as the basis for high-performance lubricants. They differ in terms of their temperature behaviour, miscibility, lubrication capability, oxidation resistance, materialcompatibility and manufacturing costs.
•If oil lubrication is notpossible or if a cooling function is not required, a lubricating grease is used in most cases.
•Pastes play a dual role in lubricants. With a high component of solid lubricants bound in oil, they perform heavy-duty work in lubrication in the mixed friction range.
•Solid lubricants are substances that form closed sliding and separating films on metal surfaces. These films are so thin that fits and tolerances donot have to be changed in mechanical engineering.
•The terms dry lubricants or bonded coatings refer to solid lubricants that are incorporate into a varnish-like matrix or organic or inorganic binders.
Normally little importance is attached to consumables like cleaners, greases, bonded coatings and assembly pastes. However, in the case of time-critical shutdown servicing, these products gain a much higherstatus, when every delay in the process means a high loss of turnover.The example of the OMV Schwechat refinery shows that in the servicingof heat exchangers, reactors, valves and the entire technical machinery, special lubricants and cleaners are the service technician’s invisible helpers. They simplify the work processes of assembly and disassembly, and also make a contribution towards the sustained process safety of the plant technology.
| |
