The hybrid gas foil thrust bearings have excellent performance, but few studies have been reported on them. In this regard, a model of this bearings is proposed and a numerical research is carried out for the static and elasto-hydrodynamic characteristics. Based on MATLAB software, a steady fluid-structure interaction method was proposed for the numerical prediction of hybrid gas foil thrust bearings. The foil deformation, static load and frictional torque were calculated and analyzed at various rotating speeds, supply gas pressures and locations of air supply holes. The influences of operating parameters and locations of air supply holes on the static performance of hybrid gas foil thrust bearings were presented. The results show that: increasing the gas pressure has a small effect on the frictional torque, but increases the axial load of the bearing, and increasing the speed will lead to a significant increase in the frictional torque of the bearing. The location of the gas supply hole arrangement has a large effect on the static characteristics of the hybrid gas foil thrust bearings, so the location arrangement should be reasonably selected. The priority is given to the arrangement of the gas supply hole in the tilted area on the basis of meeting the bearing load requirements. The conclusions are of guidance for the design and application of hybrid gas foil thrust bearings.

During the low load operation of coal-fired units, the SCR denitration catalyst may be deactivated by ammonium bisulfate (ABS). The experimental tests are carried out on this phenomenon and the results show that: 1) with the flue gas temperature below the ABS condensation temperature, the catalyst will be deactivated due to the gradual deposition of ABS in the micropores. The ABS condensation temperature is inversely proportional to the micropore diameter, and the ABS concentration is positively related to the product of NH₃ and SO₃ concentrations in the flue gas; 2) the micropores with pore diameters of 2~20 nm are still the main structure of wide temperature denitration catalyst as well as the conventional catalysts, which cannot change its fate of ABS deactivation under low load; 3) the physical reversibility of catalyst ABS deactivation makes “combination of prevention and treatment” still the fundamental method to solve the ABS problem.

The static corrosion behavior of 316L stainless steel and 347 stainless steel at 500 ℃ in Solar Salt (60%NaNO₃ + 40%KNO₃) was investigated via static corrosion test. Corrosion kinetic curves of 316L stainless steel and 347 stainless steel in molten salts at 500 ℃ were obtained through measuring the weight changes of the specimens at each time intervals. XRD and ICP-MS were employed to characterize the phase and component of molten nitrate salts; XRD, SEM/EDS were used to characterize the morphology, composition and microstructure of the corrosion products on the surface and the cross section of corroded specimens. Finally, combining the changes of molten salt and stainless steels, the corrosion mechanism of 316L stainless steel and 347 stainless steel in Solar Salt was discussed respectively. Results showed that the corrosion behavior of 347 SS in Solar Salt at 500 ℃ was characterized by mass gain. As time goes on, the trend of 316L stainless steel increased first and then decreased, while the trend of 347 stainless steel was on the increase. SEM/EDS showed that 347 stainless steel was more likely to be oxidized, while the chromium element in 347 was prone to dissolve, comparing to 316L stainless steel is better stability in Solar Salt, that is, 316L stainless steel is more corrosion resistant.

A concentrated downcomer stub of a boiler drum with 13MnNiMoR steel in a power plant, which was replaced due to cracks and non-metallic inclusions after 14 years in service, was dissected, and the behavior characteristics and influence of the non-metallic inclusion were analyzed through chemical composition analysis, mechanical property testing, microstructure and defect morphology observation. The results show that under service load, non-metallic inclusions become crack sources and microcracks by means of self cracking, interface separation from matrix or hole formation at the end, and microcracks converge to form macro cracks. When tensile and impact tests on the serviced materials, the area without inclusions was cracked and expanded in plastic mode. While innon-metallic inclusions area, the cracks nucleated with non-metallic inclusions and expanded in a brittle mode, resulting in a significant reduction in the strength and plastic toughness of the materials compared with that before service.

The growing complexity observed in the structures of cast aluminum fittings has posed significant challenges to conventional non-destructive testing techniques, rendering them inadequate in fulfilling the requirements for swift on-site inspection of irregularly shaped cast aluminum fittings. Consequently, an ultrasonic testing method based on flexible phased array probes was proposed. Firstly, a dynamic focusing algorithm for flexible phased array ultrasonic probes was introduced, and the basic simulation theory of CIVA multi-technique software platform was analyzed. Then, the dynamic focusing algorithm used to achieve deflection and focusing of ultrasonic beam was verified by simulation with CIVA, and the parameters of the flexible phased array ultrasonic probes were optimized through simulation. Finally, the effectiveness and feasibility of the testing method were verified through the inspection of typical cast aluminum fittings. The results show that phased array ultrasonic testing technology based on flexible array probes can meet the requirements of outgoing quality control and on-site rapid inspection of cast aluminum fittings with irregular shape.

A new combined cooling, heating and power system is proposed based on solar photovoltaic, wind power, ground-source heat pump and energy storage unit (WSSH-CCHP) to improve the efficient utilization of renewable energy resources and the entire system energy efficiency. The comprehensive evaluation indexes are developed by using the analytic hierarchy process to account for the system performance of energy efficiency, economy and environment. The mixed integer linear programming (MILP) algorithm is employed to perform the optimization on the selection of equipment types, capacity allocation and system operation stratagem. A case study on an energy center in Jinan city is conducted to explore the optimal performance and operation characteristics of WSSH-CCHP. The obtained results indicate that the proposed system comprehensive performance is much better than the separate production system, which provide useful information for the development of CCHP system with wind-solar-storage and heat pump and the study on its integrated optimization and operation characteristics.

According to GB/T10184—2015, the calculation model of blast furnace gas boiler efficiency is constructed, and the calculation method of blast furnace gas boiler efficiency is analyzed. The results show that the calculation methods of gas moisture content and low-level calorific value are different due to the difference of gas benchmarks.Three methods for solving the excess air coefficient, actual flue gas volume and CO₂ content in the flue gas are proposed for blast furnace gas boilers, and a correction method for exhaust gas temperature of blast furnace gas boilers with gas heaters is proposed;The calculation of some formulas in the GB/T10184—2015 needs to be further discussed, and appropriate modifications can be made.

Aiming at the problem that it is difficult to accurately and timely measure the inlet NOx concentration in the denitrification system of selective catalytic reduction (SCR) in thermal power plants, due to the excessive factors affecting the inlet NO_x concentration and the large delay and inertia of the system, the Max-Relevance and Min-Redundancy (mRMR) combined with Bayesian optimization (BO) algorithm is proposed, optimize the dynamic soft measurement model of NO_x concentration at the inlet of the SCR denitration system of the stacking ensemble model. Aiming at the problem of reduced prediction accuracy of static single model and asynchronous timing of auxiliary variables and inlet NOx concentration in the process of dynamic NO_x generation, the mRMR-BO combined with model was used to screen the auxiliary variables, Copula Entropy (CE) determined the delay of auxiliary variables, the BO combined with model determined the order of auxiliary variables, and TCN and LASSO were integrated by Stacking method. The auxiliary variables containing delay time and order information were used to construct a dynamic stacking ensemble soft measurement model, and the simulation results showed that the root mean square error, average absolute error, and average absolute percentage error of the integrated model compared with TCN and LASSO single networks were the smallest. Compared with the static ensemble model, the dynamic ensemble model has higher prediction accuracy and can achieve accurate soft measurement of the inlet NO_x concentration.

The blockage and burst failure of steam tubes caused by exfoliated oxide scales is the major risk faced by supercritical boiler in thermal power generations. With the development of advanced ultra-supercritical thermal power technology, especially, more severe oxidation scale problems will carry over into the higher steam parameters thermal power plants. High temperature coating technology shows a new research methods and approaches in solving exfoliated oxide scale problems. It can not only satisfy the performance requirements of heat resistant steel to high temperature steam oxidation resistant in harsh service environment, but also release the temperature limit of currently used heat-resistant steels due to its inadequate oxidation resistance, which has great application potential in the energy sector. The R&D plans of steam oxidation resistant coatings for steam flow parts of ultra-supercritical thermal power units in the EU, the United States and China are briefly described. The current research progress in preparation and service performance of these coatings is emphatically introduced. The basic research and engineering application issues restricting the large-scale application of aluminide coatings in thermal power units are proposed. And the application prospect of high temperature aluminide coating technology for complex heat-resistant steel tubes of ultra-supercritical power plant boiler is prospected.

In recent years, thermal power units have frequently participated in peak shaving to build a new type of power system with new energy as the theme. Accidents of pipeline weld cracking and failure often occur. The welds on both sides of the intersection between the pipeline behind the intermediate pressure bypass valve and the condenser casing frequently crack. The opening area of the muffler pipeline also frequently crack. The heat transfer process from the pipeline behind the medium pressure bypass valve to the condenser muffler is studied by using the finite element method，The distribution of thermal stress under normal and peak shaving conditions was compared. To investigate the causes of the problem, a comprehensive calculation model for the medium pressure bypass pipeline is first established to obtain the distribution of primary and secondary stresses in the pipeline under normal working conditions, as well as the displacement and bearing values of each node. The finite element method is used to study the heat conduction process from the local medium pressure bypass valve to the condenser silencer pipeline. The thermal stress distribution under normal and peak shaving conditions is studied. The results indicate that under peak shaving conditions, the poor atomization effect of the nozzle results in severe water entrainment in the steam, The temperature difference between the pipeline behind the bypass valve and the pipeline of the condenser muffler is larger and repeated operation and shutdown of the desuper heating water cause thermal fatigue fracture of the weld seam and the opening area.