A new facility at Aberdeen University is carrying out ground-breaking research for the oil industry using a range of thermal analysis instruments supplied by Mettler Toledo
Aberdeen Thermal Analysis Service (ATAS) is affiliated to the Scottish Offshore Materials Centre (SOMC), which has received grant funding to the value of £0.75million to enable it to test materials under extremes of pressure and temperature.
Professor Corrie Imrie explains why the work of the ATAS is critical to the North Sea oil industry: "As new fields are opened, the industry is finding itself dealing with ever higher temperatures and pressures and we simply do not know how various materials will behave in these conditions.
The materials we concentrate on are the elastomers used for making seals.
With the Mettler Toledo equipment, we are characterising these materials before and after being subjected to extremes in both sour well conditions, where hydrogen sulphide is present, and sweet well conditions, where carbon dioxide is found." The procedures for which ATAS uses Mettler Toledo instruments include differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and thermogravimetric analysis - mass spectrometry (TG-MS).
The laboratory has two Mettler Toledo DSC instruments, a DSC820 and a DSC821e for looking at heat capacity, how materials change as a function of temperature and phase changes in materials.
The former operates from -50 to 700C and has sub-ambient cooling provided by an Intracooler, whilst the latter operates from -150 to 700C and uses liquid nitrogen for sub-ambient cooling.
Both machines are equipped with a sample robot, which allows the automated throughput of up to 34 samples, which are generally cycled in sealed aluminium pans.
In standard operating conditions, the samples are heated at 10K/min, although the instrument can heat at up to 50K/min.
Cooling rates depend on the type of cooler, with the Intracooler achieving 20-30K/min and the liquid nitrogen device reaching 30-40K/min.
For thermomechanical analysis, to investigate thermal coefficients, ATAS is using a Mettler Toledo TMA/SDTA840 which operates from 25 to 1100C.
For most of the tests carried out, the heating rate is usually set to 2-4K/min with the cooling rate set over a similar range as behaviour on cooling can produce results which are of interest. The samples can be run in aluminium pans or as 'sandwiches' using quartz discs, with a maximum sample size of 20mm.
The Mettler Toledo TGA/SDTA851e is used in conjunction with a ThermoStar mass spectrometer.
This combination considerably increases the power of the system, which is used to identify degradation products coming off samples.
The TGA operates from 25 to 1600C and can be run under different atmospheres, such as oxygen and air, where an oxidising environment is required, or nitrogen for an inert environment. The mass spectormeter will collect data on species between 0 and 300amu, and can be set to sweep over the full range or tuned to search for particular fragments.
While a large amount of the work carried out by ATAS as an integral part of SOMC, it also carries out a wide range of work for other organisations.
Its range of activities covers routine analysis, problem solving, longer-term collaborative projects and basic research.
Work funded by other research bodies includes projects for the Engineering and Physical Sciences Research Council (EPSR) looking at the structure of various natural and synthetic hydrogels, assessing their structure and changes which occur under various conditions and range of programmes involving liquid crystalline materials. Work for the pharmaceutical industry has been carried out to detect residual solvents which come off products at various temperatures and the laboratory has also done a considerable amount of work on testing wax appearance temperatures on various oils.
Because of the range and complexity of the work being carried out by ATAS, quality and reliability were high on the list of priorities in choosing the laboratory equipment.
Equally important to Corrie Imrie, however, is the backup provided by Mettler Toledo's research and development team.
He says: "The company's R&D is first class and talking to them from a university environment is very easy.
They are very willing to collaborate with active researchers and we always know that if we hit a problem, we can take it to them.
Even if it is something they have not encountered before, they will go away and look at it for us.
The feedback we get from them is excellent, which is very important when you are carrying out ground-breaking work."
