Pretreatment and enzymatic hydrolysis of straw type biomass are among the key technologies for its high value conversion and utilization. Using corn stover as the raw material, pretreatment methods with formic acid, sodium chlorite, and alkaline hydrogen peroxide were studied and compared. Methods such as scanning electron microscopy, Xray diffraction, and Fouriertransform infrared spectroscopy were employed to analyze the composition, morphology, crystal structure, and functional groups of corn straw before and after pretreatment. After pretreatment with formic acid, sodium chlorite, and alkaline hydrogen peroxide, the lignin removal rates were 66.71%, 97.12%, and 91.88% respectively, and the enzymatic hydrolysis rates reached 63.26%, 71.83%, and 95.14% respectively. Under the conditions where the cellulase dosage is 19.6 FPU/g, the xylanase dosage is 35.44 IU/g, and the Tween 80 dosage is 20.96 mg/g, the predicted enzymatic hydrolysis rate of corn straw pretreated with alkaline hydrogen peroxide is 95.57%, while the actual enzymatic hydrolysis rate is 94.42%. The optimal feeding strategy for high solid enzymatic hydrolysis was an initial substrate concentration of 8%, with 4% of the substrate added at 6, 12 h, and 24 h respectively. After 120 h of enzymatic hydrolysis, the enzymatic hydrolysis rate reached 87.57%.

In order to comprehensively evaluate the power generation performance of solar cells, aiming at solving the problem that the existing photovoltaic (PV) equivalent circuit model cannot estimate its spectral response characteristics, in this paper, an equivalent physical model of solar cells and its parameter identification method based on the finite element method is proposed to estimate its electrical characteristics and spectral response. Firstly, the influence of key parameters in the finite element model on the estimation results of electrical characteristics is analyzed. Six parameters, including the thickness of the emitter region, the thickness of the base region, the doping concentration of the emitter region, the doping concentration of the base region, the series resistance, and the parallel resistance, are determined as the model parameter identification objects. Then, based on the measured currentvoltage (IV) characteristic data under high irradiation conditions, the particle swarm optimization algorithm is used to identify the above parameters. Finally, the IV characteristics under different irradiation and temperature conditions are measured and compared with the model estimation results. Meanwhile, the solar spectrum curves are measured to indirectly verify the accuracy of the spectral response of the solar cell estimated by the model. The experimental results show that the root mean square error (RMSE) of the estimated current for monoSi and polySi cell models are in the range of 0.019 2 A to 0.030 2 A and 0.018 0 A to 0.051 5 A, respectively. The absolute percentage error between the estimated shortcircuit current and the measured shortcircuit current is concentrated below 15%. The proposed equivalent physical model of solar cell and corresponding parameter identification method can comprehensively reflect its actual performance.

In transmission lines, due to the influence of line impedance, it is difficult for energy storage power station systems to allocate power reasonably according to capacity. In order to better promote the stable operation of black start, this article proposes a battery power distribution scheme for energy storage power plants based on improved Virtual Synchronous Generator (VSG). This scheme first introduces virtual impedance to eliminate bus voltage fluctuations caused by line impedance, in order to improve the accuracy of power allocation in energy storage power station systems; Then, in response to the problem of uneven power distribution among multiple energy storage units in parallel in an energy storage power station due to the influence of line impedance, the power transmission and circulating characteristics of multiple energy storage devices in parallel were analyzed to continuously improve the black start system. Finally, experimental analysis was conducted using Matlab/Simulink and semi simulation platforms to verify the effectiveness of the proposed strategy, which can improve the stability and economy of system operation.

This paper takes GE 9HA.02 combined cycle unit as the research object, and innovatively proposes the design scheme of a hydrogen natural gas mixing integrated system in gas turbine power plant, with gas hydrogen long tube trailers as the main hydrogen transmission method and reserved pipeline gas inlet interface. Through the configuration of a hydrogen compressor bypass system, the residual hydrogen stored in the long tube trailer was fully utilized, improving the utilization rate of trailer hydrogen storage. At the same time, a comparative analysis was conducted on the economic feasibility of adding hydrogen to the 9H class gas turbine power plant. Electricity price and natural gas price are more sensitive to the impact on the internal earing rate of return. And in order to meet the requirements, hydrogen price cannot exceed 38.5 yuan/kg. With the development of renewable hydrogen production technology, and driving the further reduction of hydrogen production costs, the promotion and application of hydrogennatural gas mixing integrated system will become increasingly competitive.

The low energy consumption and mild storage and transportation conditions of the clathratebased solid natural gas technology make it a key factor in promoting the development of the natural gas industry. However, the slow hydrate formation kinetics has hindered its application. This article explores the formation laws of methane hydrates supported by porous media (activated carbon and quartz sand) under the action of 1,3dioxolane. It analyzes the hydration efficiency in different systems, evaluates the synergistic and antagonistic effects of 1,3dioxolane and porous media on hydrate growth, and clarifies the influence of the pore structure. The results show that: under high pressure, the adsorption of 1,3dioxolane by the pore structure of activated carbon leads to an antagonistic effect between the two, resulting in poor hydration efficiency. Moreover, as the initial pressure and the concentration of 1,3dioxolane increase, the antagonistic effect intensifies. Under low pressure, there is a synergistic effect between 1,3dioxolane and activated carbon. The hydration efficiency is affected by pressure. The free 1,3dioxolane enhances the formation of methane hydrates and increases the gas storage capacity of hydrates. 1,3Dioxolane enhances the formation of hydrates in the quartz sand system. However, the rapidly growing hydrates limit the conversion of internal water, making this enhancement effect achieve the best performance when the initial pressure is 5 MPa.

This article proposes an intelligent charging station energy scheduling system based on machine learning, which is applied to public fast charging station microgrids equipped with photovoltaic systems and energy storage systems using secondary life electric vehicle batteries. The energy dispatch system can be used to address the uncertainty of energy demand for electric vehicles and the power gap between grid connection and fast charging services. In addition, this article uses machine learning methods to automatically synthesize suitable energy scheduling systems based on fuzzy rules. The energy dispatch system proposed in this article considers different electric vehicle fleets and photovoltaic scales, providing a reference for the optimal scale of photovoltaic systems and the effectiveness of nanogrid systems. Finally, in the experiment, a mixed deterministic stochastic process was used to simulate the energy demand of electric vehicles, which showed an improvement in performance compared to the optimal benchmark solution. This indicates that the system can more effectively handle the energy demand uncertainty of electric vehicles and the power gap between grid connection and fast charging services.

When the doublyfed machine is connected to the grid, it can support or raise the frequency of the grid by compensating the active power, but the rotor speed decreases quickly and is not controllable, the time of active power compensation and frequency support is limited, and the stability of motor can not be guaranteed. This paper presents a frequency support technique for doublyfed machine (DFIG) phase modulation system with flywheel energy storage based on virtual synchronization control and dynamic speed limit. Firstly, the flywheel is hung on the rotor shaft of the doubly fed machine to increase the inertia of the system, and the mechanical energy storage, and delay the rotor speed decline rate in the process of frequency drop. Secondly, when the frequency of power grid drops, the realtime compensation of active power is carried out by means of virtual synchronization control strategy, and the compensation time of active power is regulated on demand based on the dynamic control of the lower speed limit of rotor. Finally, the validity of the proposed frequency support technology is verified by Matlab/Simulink simulating.

Aiming at the unbalanced load that the wind turbine is subjected to when it operates above the rated wind speed, an independent pitch control strategy that combines the Radial Basis Function (RBF) neural network and Model Predictive Control (MPC) is proposed. A meanperiod statespace model suitable for controller design is established by means of wind turbine dynamics equations and coordinate transformations. On the basis of Kalman state observer, the model predictive control is used to adjust the pitch angle of the wind turbine instantaneously and the RBF controller to suppress the loads, and then the required independent pitch controller is designed. Taking the NERL 5 MW wind turbine platform as an example, the load characteristics of the independent pitch control strategies based on Proportional Integral (PI), MPC, and MPCRBF are analysed under turbulent winds, as well as their operating characteristics. Simulation results indicate that the method can reduce the load efficiently, improve the operating life of the wind turbine, and have a better suppression effect on the power fluctuation.

With the construction of the energy internet and the proposal of the dual carbon goal, the quantitative assessment of carbon emissions of multienergy systems is a key link to achieve lowcarbon operation of the system. Therefore, an optimal operation model of multienergy system considering wind power and PV development trend and carbon emission assessment is proposed in this paper. Firstly, by analyzing the energy input and output characteristics of thermal power units, gas turbines, P2G, and multienergy storage equipment, the topology and multienergy power balance model of the multienergy system are established; Secondly, the generalized Bass model is used to quantify the development trend of wind power and photovoltaic. On this basis, a carbon emission assessment model of the multi energy system considering the development trends of wind power and photovoltaic is established; Then, with the goal of maximizing the total revenue including energy regulation revenue, carbon quota trading revenue and operating cost of multienergy system, an optimal operation model of multienergy system considering wind power and PV development trend and carbon emission assessment is proposed. Finally, the results of the example show that the optimization operation model of multienergy system proposed in this paper can effectively improve the operational benefits and reduce carbon emissions of the multi energy systems.

The heat transfer efficiency of the solar air collector with smooth heat absorption plate is very low. Using artificial roughness on the absorption plate can interrupt the boundary layer and improve the heat transfer efficiency of the system. The improvement is made based on the rectangular artificial roughness, and a twodimensional simulation of the solar air collector with the rightangle hexagonal artificial roughness is performed using ANSYS FLUENT. The influence of artificial roughness spacing on heat transfer efficiency and flow characteristics in the specific Reynolds number range is discussed, and the thermohydraulic performance is evaluated under different working conditions. The governing equations are solved using the finite volume method and the transport equations of the turbulent kinetic energy and the turbulent dissipation rate are solved using the RNG kɛ turbulence model. The result show that the heat transfer characteristic of the system is significantly improved by the addition of the rightangle hexagonal artificial roughness compared to the smooth plate. The rightangle hexagonal artificial roughness with p = 10mm had the maximum THPP of 1.76 at Re=4000, which is 1.6 times the artificial roughness of the rectangle under the same geometric parameters.