This paper briefly describes the research status of oil shale pyrolysis technology and the main factors affecting oil shale pyrolysis, with emphasis on four kinds of commonly used catalysts: The effects of natural minerals, metal compounds, molecular sixes, and supported catalysts on the pyrolysis of oil shale were discussed. The changes of the pyrolysis mechanism and product composition of oil shale with the addition of different catalysts were discussed. Finally, the development direction of preparation of new catalysts was discussed, in order to provide a prospect for the development and utilization of unconventional and strategic alternative energy resources around the world.

The main methods of treating oily sludge at home and abroad and the current research status of oily sludge pyrolysis technology are briefly described, and four commonly used catalysts are introduced: metals, metal compounds, molecular sieves, metal-supported molecular sieves, and biomass catalysts for oily sludge. The influence of pyrolysis, the pyrolysis mechanism, and the product composition of oily sludge with the addition of different catalysts are also discussed. Finally, the development direction of preparing new catalysts and the mixed use of multiple catalysts is proposed as a theory to provide for the efficient and reasonable utilization of oily sludge.

Martensitic stainless steel containing 13% Cr–4% Ni suffers cavitation erosion (CE) as the common material of hydro turbine impellers. Two 13% Cr–4% Ni stainless steel samples were obtained by different melting and heating processes. One was of relatively low toughness but high ductility (LTHD), and the other was of relatively high toughness but low ductility (HTLD). This paper is to clarify the relationship between the mechanical properties and the CE resistance of the experimental steel samples. The CE of the two materials was studied using an ultrasonic vibration cavitation erosion rig. Mass loss, morphological observation, nanoindentation characterization, and tensile tests were employed to clarify the erosion mechanism. The results showed that LTHD stainless steel had slightly higher ductility, but lower toughness than HTLD material. The mass loss method verified that the CE resistance of LTHD material was higher than that for the HTLD material. In addition, both materials had an incubation stage of 2 h in the distilled water. The SEM revealed that material removal was preferentially initiated from the grain boundaries and slip zone after the incubation period. The ductility could delay the fracture of the material, which contributed more to cavitation erosion resistance than the toughness of the materials. The hardness test showed few relationships with the CE resistance.

Weld corrosion exists widely in the petrochemical industry and attracts great attention. Most research proves that weld corrosion originates from the material factors introduced during the welding process. However, it is noted that local fluid turbulence due to the weld reinforcement height (WRH) plays an important role in the non-uniform corrosion of welds in flowing media. Accordingly, the individual effect of the local flow on the weld corrosion of low alloy steel was analyzed by experiments and simulation in this study. Electrochemical measurements and morphology observation were conducted, combined with flow field analyses. The results showed that local fluid turbulence due to WRH affected the non-uniform corrosion of low alloy steel welds. The upstream surface and the backflow surface had the highest and lowest corrosion rates, respectively. Interestingly, the high flow velocity surface region did not have a high-corrosion rate. This is due to the combined effects of mass transfer, charge transfer, and wall shear stress. The pitting corrosion was also discussed in view of the aspects above.

Erosion wear is a primary factor in material failure and is widely observed in hydropower, petroleum, aerospace, and other industrial fields. It is evident from the findings of numerous research studies that both the characteristics of particles and the fluid dynamic parameters are significantly associated with the occurrence of erosion damage. However, there has been a paucity of research into the correlation between the mechanical properties of materials and their erosion wear behaviour. This review methodically summarises the latest understanding of erosion wear mechanisms and influencing factors, with a specific focus on how the mechanical properties of materials regulate erosion processes. Furthermore, it provides a concise overview of erosion mechanisms and fluid dynamic factors, while undertaking a critical evaluation of the discrepancies observed among various erosion wear rate prediction models. The overarching objective of this research is to enhance mechanistic comprehension, facilitate the integration of prediction models with material property databases, and furnish a theoretical foundation for the design of erosion-resistant materials and the development of industrial protection strategies.