Computational fluid dynamics-chemical reactor network (CFD-CRN) simulation is a suitable method for predicting NO_x emissions from gas turbines. A universal CRN automatic partitioning/solving program was developed and then applied and verified on a natural gas micro-mixing combustor. Through analysis of flow and combustion characteristics in the micro-mixing combustor based on CFD simulation, CRN partitioning criteria are established: firstly, the air and fuel zones are extracted, then major zones along the axial direction are divided, and further the zones are subdivided radially/circumferentially according to fuel-staging locations. The results indicate that, the CRN automatic partitioning/solving program enhances generality by using an XML standardized information interface and is suitable for complex combustor structures. The relative error between the predicted and experimental NO_x emissions under different operating conditions of the micro-mixing combustor is less than 11%, and the influence of CFD grid number on the NO_x prediction by CRN is relatively small. The effect of fuel distribution ratio on NO_x emissions from micro-mixing combustor is analyzed, and a suitable adjustment range is given. The proposed CRN automatic partitioning/solving algorithm has potential applications in predicting NO_x emissions from gas turbines.

Low-temperature adsorption technology for coal-fired flue gas pollutants can synergistically remove various pollutants and achieve near-zero emission. Focusing on the key equipment of this technology, flue gas spray cooling tower, ANSYS Fluent software is used to simulate the inside of the tower, and the impacts of various parameters are analyzed. The results indicate that, increasing the spray height effectively extends the contact time between flue gas and cooling water, thus significantly enhances heat exchange. Reducing the temperature of the cooling water strengthens the tower’s cooling capacity. Additionally, moderately reducing the inlet flue gas velocity increases its residence time in the tower, promoting more thorough heat exchange. Reducing the droplet diameter of the cooling water enhances the heat transfer efficiency by increasing the contact area. Enlarging the spray angle extends the residence time of cooling water within the tower and lengthens the contact duration with flue gas, boosting heat exchange. Increasing the cooling water flow rate expands the heat exchange area, further improving the heat transfer performance. The addition of packing material improves the heat exchange capacity of the tower while conserving cooling water. Comprehensively optimizing these parameters can substantially reduce the temperature of cooled flue gas, providing theoretical support for the design, manufacturing, and optimization of spray cooling towers in the low-temperature adsorption technology for coal-fired flue gas pollutants.

A resin-based solid amine adsorbent was prepared based on in-situ synthesis technology. The effects of air humidity (30%~90%), adsorption temperature (30~90 ℃) and adsorption time on the adsorption performance of CO₂ were investigated. Moreover, the adsorption kinetic characteristics of the adsorbents at different air humidities were studied. The results showed that, the maximum CO₂ adsorption capacity of the resin-based solid amine adsorbents in the air reached 2.38 mmol/g, and the air humidity and adsorption temperature had significant effects on the adsorption rate. The optimal adsorption efficiency was obtained when the air humidity was higher than 50% and the adsorption temperature was 25~50 ℃. The adsorbent exhibits very good cycle stability due to its excellent high temperature resistance.

Constructing a large-scale virtual power plant (L-VPP) based on coal-fired units is a vital strategy for achieving “dual-carbon” goals by enabling renewable energy integration and supporting the transition of coal-fired power generation. A dynamic simulation model of the L-VPP and a source-storage frequency regulation control system model are established, which include a 350 MW coal-fired unit, a 100 MW photovoltaic unit, a 90 MW·h battery energy storage system, and internal loads. The frequency response characteristics of the L-VPP are analyzed for various control systems and at different load ramp rates of the coal-fired unit. The results reveal that, the load ramp rate of the coal-fired unit is a critical constraint on frequency response capability when storage capacity is limited. The complementary frequency response characteristics between the source and storage are obtained, leading to a coordinated control strategy that incorporates auxiliary power commands and cyclic determination mechanisms. Simulations demonstrate that the proposed strategy lowers the frequency nadir by 0.06 Hz and shortens the steady-state recovery time by 18.6%. Furthermore, to achieve a steady-state error within the frequency dead band, the load ramp rate of the coal-fired unit is increased from below 3.50 MW/min to 7.00 MW/min. This strategy offers technical guidance for the safe and efficient operation of large-scale virtual power plants.

To solve the problems of slagging and burner burnout caused by lean coal boilers which convert to firing Shenhua bituminous coal, a 600 MW supercritical opposed firing boiler was taken as the research object. Through thermal calculation and numerical simulation analysis, a feasibility study for the combustion system retrofit scheme was carried out with emphasis. The results show that, by adopting differentiated heat load design, inclined installation of side wall burners into the furnace, and multiple dimensions of wall mounted wind, the heat load in the burner area reduced from 1.71 MW/m² to 1.44 MW/m², and the flue gas temperature at the furnace outlet decreased from 1 058 ℃ to 1 010 ℃. The performance test results after the retrofit show that at rated load, the unburnt carbon content of coal ash decreased from 6.06% to 1.42%, the boiler efficiency increased from 92.76% to 94.03%, and the NOx emissions at the furnace outlet reduced by 50%~60% at various loads. The boiler can operate safely and efficiently for a long period. The proposed transformation technology scheme has guiding significance for the optimization and retrofit of combustion systems of similar units under the condition of converting low volatile coal to bituminous coal.

Improving the flexibility of coal-fired power units is the key to achieving a green and low-carbon power system. Molten salt energy storage technology, as a sensible heat energy storage technology, can provide frequency regulation, peak regulation, and industrial heating decoupling support for power generation units. Combining with the engineering application of a coal-fired power unit coupled with molten salt energy storage, the thermal performance of heat storage, heat release and energy cycling are systematically analyzed, and performance evaluation indicators are proposed. The results show that, the molten salt thermal storage system significantly enhances the flexible operation capability of the unit, achieves decoupling between industrial steam supply and deep commissioning peak of the unit, and improves the frequency regulation performance by 150%. The thermal efficiency of the thermal storage system is maintained at around 92%. This study provides a reference for the application of flexibility renovation projects for coal-fired power plants based on molten salt thermal storage technology.

A comparative test was conducted on operating oil samples from wind turbine gear oil and a fresh oil sample, revealing that the Fe³⁺ content was the most rapidly deteriorating indicator. The SG-PEI adsorbent was prepared by loading polyethyleneimine (PEI) onto a silica gel material (SG) through impregnation modification, and its characteristics were evaluated. The adsorption isotherms and kinetics of Fe³⁺ on SG-PEI were thoroughly investigated. The results indicated that, the adsorption isotherm of Fe³⁺ on SG-PEI conforms to Langmuir model. The saturated adsorption capacity of SG-PEI for Fe³⁺ was 28.71 mg/g, representing a 39.2% improvement compared to SG (20.63 mg/g). The adsorption process of Fe³⁺ on SG-PEI adhered to the pseudo-second-order kinetic model, with adsorption process occurring as a spontaneous exothermic reaction. Under optimal conditions of an adsorption temperature of 60 ℃, an adsorption time of 120 min, and an oil-adsorbent ratio of 100:3, the removal rate of Fe³⁺ from wind turbine gear oil by SG-PEI reached 96.23%, which is 29.43 times higher than that of the 801 adsorbent (3.27%) and 185.06 times higher than that of Al₂O₃ (0.52%). The SG-PEI has a good prospect for applications due to its high adsorption capacity and selectivity for Fe³⁺.

Based on the application of micro-channel printed circuit heat exchangers in fields such as thermoelectric power generation and aerospace, a high-efficiency, low-resistance, and easy-to-manufacture transverse slotted channel is proposed using the theory of boundary layer re-development, and the heat transfer is enhanced. Numerical simulations are employed to study the flow and heat transfer characteristics of both straight and slotted channels. The mechanisms of heat transfer enhancement and flow resistance reduction in the transverse slotted channel are investigated. The results show that the entrance effect can significantly enhance heat transfer with a minimal increase in flow resistance. The transverse slotted channel creates multiple entrance effects in the slotted regions by inducing flow separation, which leads to periodic boundary layer redevelopment, thereby greatly enhancing local convective heat transfer. Additionally, due to the relatively small velocity gradient in the slotted regions, local resistance is effectively reduced. As a result, the proposed transverse slotted channel improves the heat transfer capability of the channel by 2.24%~2.59%, reduces the resistance by 6.66%~7.91%, and increases the overall heat transfer performance by 9.87%~11.02%.

In order to effectively improve the energy efficiency and operational flexibility of solar power generation, an integrated system coupling solar photovoltaic, solar thermal and compressed air energy storage is proposed. During the day, the compressed air energy storage system will store the photovoltaic abandoned power, and transfer the compression heat to the photothermal power station. At night, the compressed air energy storage system releases air and uses water supply of the photothermal power station to heat up, thereby increasing the power generation load of the unit. Based on the system simulation, the coupling scheme is analyzed thermodynamically and economically. The overall generation efficiency of the coupled system is 41.24%, while the overall exergy efficiency is 66.79%. The round-trip efficiency of the compressed air energy storage system is 72.14%, while the exergy efficiency of the compressed air system is 84.30%, both of which have increased significantly. The peaking depth of the coupled system is 7.02% in the daytime and 19.69% in the evening. In addition, the dynamic recovery cycle of the coupling scheme is 3.10 years, and the net present value is 41.350 6 million yuan.

Under the “dual-carbon” target, ammonia as a zero carbon fuel is expected to become a substitute for fossil fuels. Focusing on the problems of slow combustion speed, high ignition energy, and significant ignition delay in ammonia combustion, the effects of initial temperature, pressure, and oxygen volume fraction on ammonia combustion characteristics are studied via Chemkin simulation, based on the different ammonia combustion chemical reaction kinetics mechanisms of Shrestha, Mei, Mei-2021, Stagni, CEU-NH₃, Gotama, and Glarborg. The results show that, as the initial temperature increases, the propagation speed of ammonia laminar flame increases, and the ignition delay time decreases, which is beneficial for ammonia ignition and combustion. The increase in pressure reduces the propagation speed of laminar flames, but significantly shortens the ignition delay time. The increase in pressure is beneficial for ignition but not conducive to flame propagation. As the volume fraction of O2 increases, the laminar flame propagation speed increases and the peak shifts towards lean combustion. Sensitivity analysis reveals that the branching ratios of H+O₂=O+OH, H₂+NO=NNH+OH, and NH₂+NO=H₂O+N₂ have a positive promoting effect on flame propagation, while that of NH₂+O=HNO+H inhibits flame propagation. The reactions H+O₂(+M)=HO₂(+M), NH₃=H+NH₂, HNO=H+NO, and NH₂+HO₂=NH₃+O₂ exhibit high sensitivity at high pressures. The sensitivity coefficients of the reactions between HNO and N_iH_i is relatively high during lean burn combustion. H₂NO is an important intermediate component that affects the ignition delay time at high pressures and low temperatures. By optimizing the conditions of ammonia combustion and regulating key reaction pathways and reaction kinetics, the characteristics of ammonia combustion can be improved.