No abstract

The effects of gaseous hydrogen chloride and hydrogen sulphide on the hightemperature corrosion of the austenitic SS. S31400 and the duplex steel S32205 were investigated in an atmosphere without molecular O 2 . The testing gas atmosphere consisted of 3.8 vol% HCl, 1.9 vol% CO 2 , 0.3 vol% CO, 2.8 vol% H 2 , 0.02 vol% H 2 S, bal. N 2 . It showed a similar composition, which is present in the thermal cracking of anthropogenic resources. Tests were performed between 480 and 680°C for 1, 3 and 10 days. Mass loss measurements were done for all experiments. After the reaction times the samples showed non-adherent and porous layers of corrosion products, which were investigated by SEM/EDX and XRD. Metallographic cross sections of the corroded samples were prepared by water-free polishing to investigate the microstructure of the corrosion products. Both materials formed large chromium sulphide crystals on top of a chromium oxide layer and a chlorine-containing layer beneath the oxide. The ferrite phase of the duplex steel is selectively attacked, while the austenite phase remained without severe corrosion. Steel S31400 showed a uniform corrosion.

No abstract

No abstract

The alloys K90941 and N08811 were tested under conditions simulating a pyrolysis process of post-consumer plastics. Impurities in the plastic feedstock like chlorine containing materials or organic components yield HCl and H2S respectively during the cracking process. The reactor material must be able to withstand these harsh corrosive conditions.In lab-scale test equipment, process conditions of the reactor zone of the pyrolysis process were simulated at temperatures of 420 °C and 580 °C for 72 h. The gas atmosphere consisted of either 200 ppm or 20000 ppm H2S and 3.8 vol% HCl, 1.9 vol% CO2, 0.3 vol% CO, 2.8 vol% H2, bal. N2. After the corrosion experiments, the samples were analyzed by metallography, SEM/EDX, and XRD. Additionally, the mass loss was evaluated. Results show that the ferritic K90941 is more aggressively attacked than the austenitic N08811 and that for both materials the mass loss rises with increasing H2S content in the gas atmosphere and increasing temperature.

No abstract

Summary Tense economic situations push the demand for low-cost oil production, which is especially challenging for production in mature oil fields. Therefore, an increase in the meantime between failure and the limitation of equipment damage is essential. A significant number of wells in mature fields are suffering under sand by-production. The objective of this paper is to show the development process and the testing procedure of an in-house-built, effective downhole desander for sucker rod pumps on the basis of a sophisticated analytical design model. In weak reservoir zones, often the strategy to prevent equipment damage due to sand by-production is the sand exclusion method using a gravel pack. Nevertheless, a certain amount of small sand grains still enter the wellbore and may damage the sucker rod pumping system over time. In early 2018, various types and sizes of downhole desander configurations were tested at the pump testing facility (PTF) at the University of Leoben (Montanuniversitaet Leoben). In a period of about 4 months, testing took place under near field conditions to find the optimum and most efficient design. The design optimization was focused on the geometry of the swirl vanes and the sand separation distance at the sucker rod pump intake. An analytical model provided the basis for geometric optimization. Concurrently, field tests of the in-house downhole desander were performed in the Vienna Basin that confirmed the findings of the tests at the PTF. The test results have shown that the downhole desander design and the pumping speed are the most influencing parameters on sand separation efficiency. Poor design in combination with a wrongly selected pumping speed can reduce the sand separation efficiency to lower than 50%, while if all parameters are chosen correctly, the sand separation efficiency can be 95% or higher. The grain size distribution is the additional parameter that enables a decision and ranks the performance. The sensitivity analysis, performed for several downhole desander types, has shown the high dependency of the sand separation efficiency on the major desander design parameters. Proper selection of the components and operating parameters will contribute to an increase in the meantime between failures. This paper will present the testing configurations, the development of the high-efficiency in-house downhole desander, and the sensitivity analysis performed on the design.

Steel 1.4841 was tested as a possible reactor material for a cracking process of anthropogenic resources under simulated laboratory conditions at 680 °C. The gas atmosphere present in this process contains HCl as well as H2S.In order to evaluate the corrosion behavior, metallographic sections were prepared from the corroded samples. The preparation for the SEM/EDS examination had to be performed under exclusion of water, as otherwise the readily water-soluble metal chlorides would not have been detected.A layered, porous structure of the corrosion products (oxides and sulfides of Cr) could be observed. The lowermost layer contains chromium and iron chlorides. Nickel could not be found in any of the corrosion products.In order to estimate the long-term resistance, aging tests were performed at 680 °C in an inert atmosphere for up to 1600 h before the actual corrosion tests. The formation of Cr23C6 and also of Ϭ phase could be evidenced by TEM. Compared to the non-aged samples, the chromium depletion caused by aging resulted in slightly increased corrosion rates.