Archive

  • Select all
    |
    Topic on Efficient Utilization of Biomass Energy Resources
  • Topic on Efficient Utilization of Biomass Energy Resources
    Research Progress in Pyrolysis and Conversion of Lignocellulosic Biomass
    YAO Lei, GE Lichao, ZHAO Can, WANG Ruikun, ZUO Mingjin, ZHANG Yuli, WANG Yang, XU Chang
    2024, 44(5): 665-680. https://doi.org/10.19805/j.cnki.jcspe.2024.230625
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This paper provides a comprehensive review of the research progress in lignocellulosic biomass pyrolysis technology. The pyrolysis mechanism of various biomass raw materials are summarized, the composition and properties of the products are analyzed, and the regulation, modification and application of the products are reviewed with emphasis. The results indicate that future research directions should focus on the following aspects: technological improvement, committed to improving biomass pyrolysis technology, enhancing energy conversion efficiency and product selectivity; diversification of products, in addition to the main energy products generated by biomass pyrolysis, such as biochar, bio-oil, and biogas, developing high-value chemicals and materials, including bio based chemicals, special chemicals, and high-performance materials should also be focused on; integration with other energy conversion technologies to establish a multi-energy co-supply system by combining biomass pyrolysis with the processes like biomass fermentation, photocatalysis, electrolysis, and energy storage technologies.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Analysis and Optimization for Practical Applications of Clean and Efficient Combustion of Large-scale Grate Furnace
    ZHANG Ruizhi, WANG Linzheng, ZHAO Shanhui, DENG Ruiqu, LUO Yonghao
    2024, 44(5): 681-691. https://doi.org/10.19805/j.cnki.jcspe.2024.240003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Large-scale grate furnaces have been widely used in the energy conversion of biomass and municipal solid wastes (MSW). However, due to the fact that design and operation of grate furnaces are still in the stage of engineering exploration, in the actual operation process, there are still problems such as high excessive air rate, poor combustion efficiency in both gas and solid phase, and high initial NOx emissions. In response to the complex layered combustion process of grate furnaces, a large-particle conversion model and a multi-component parallel particle combustion model were constructed to achieve fine numerical simulation of actual grate furnace combustion processes. The accuracy of this model was verified by comparing with experimental results. Using numerical simulation methods, real-furnace analysis and optimization were carried out for large-scale grate furnaces burning MSW and agricultural straw. Based on the surface- and bottom-ignition modes, on-site adjustments were made. Results show that for the middle-arch SW incinerator, localized high temperature and high NOx emission are mainly caused by the departure of component distribution, combustion and reduction reactions from design, which are clearly improved by the operation adjustment. According to numerical modeling calculation, a further optimization in its structure can reduce NOx emission to 26.8 mg/m3. For the vibrating grate boiler for straw, low combustion efficiency in gas and solid phase is mainly caused by the convective cooling of large primary air and the "chimney-like flow" in furnace. After optimization, its emission is hugely reduced, and power-generation load remarkably rises.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Simulation Study on Nitrogen Oxide Formation Characteristics in Co-combustion of Coal and Agricultural Waste in Fluidized Bed Boiler
    ZHANG Tao, DAI Liangxu, WANG Chang'an, YANG Kun, YUAN Tianlin, CHONG Peian, CHE Defu
    2024, 44(5): 692-702. https://doi.org/10.19805/j.cnki.jcspe.2024.230724
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A combustion reaction model for fluidized bed boiler was established through the chemical reaction kinetics simulation method. The nitrogen oxide formation characteristics and reaction mechanisms during co-combustion of coal and agricultural waste were studied. Results show that the conversion ratio of nitrogen oxide increases with the increase of the co-firing ratio of wheat straw, and the conversion ratio is raised more greatly with more blended biomass. The combustion temperature has a significant influence on the conversion ratio of nitrogen oxide. With the increase of oxygen concentration in the combustion system, the conversion ratio of nitrogen oxide increases slowly first and rises rapidly when the oxygen concentration reaches a certain value, and then hardly changes. For both economic and technical feasibility considerations, it is possible to further reduce nitrogen oxide generation by reducing the oxygen concentration of over fire air that has a small flow rate. The conclusions can be the technical support and guidance for the control of pollutant emission in the practical boiler of coal co-firing with biomass.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Study on Co-combustion Behaviour of Biomass with Gangue (Coal Kaolin) and Retention Characteristics of Alkali Metals
    LI Hao, LIU Haiyu, QIAO Xiaolei, XIE Yuting, JIN Yan
    2024, 44(5): 703-709. https://doi.org/10.19805/j.cnki.jcspe.2024.230517
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Using thermogravimetric (TG) technique and inductively coupled plasma emission spectrometer (ICP-OES), the combustion characteristics of individual straw and coal gangue and their co-combustion characteristics, the retention characteristics of alkali metal elements in straw were investigated, and the kinetic characteristics of the co-combustion process of straw and coal gangue were analyzed using the Coats-Redfern integral method. Results show that in the co-combustion process of straw and gangue, there is a strong interaction, in which the best combustion characteristics are achieved with the gangue mixing ratio of 10%. With the increase of coal gangue addition, the combustion reaction activation energy of the fixed carbon in the mixtures decreases and the interaction gives rise to a change of reaction mechanism in the combustion process; the best inhibition effect for the release of alkali metals is attained with the gangue mass fraction of 10%, meantime the best retention effect of alkali metals K and Na is also attained at 1 000 ℃ and 1 100 ℃, respectively.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Study on the Factors Affecting Gasification and Slag Formation of Biomass Briquettes in Fluidized Bed
    FAN Haodong, LI Jianghao, ZHANG Han, ZHANG Xiong, ZHANG Shihong
    2024, 44(5): 710-718. https://doi.org/10.19805/j.cnki.jcspe.2024.230747
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To enhance the quality of biomass gasification products, briquettes of eucalyptus bark and corn stalk were used as the typical feedstocks for the fluidized bed gasification experiments. Rice husks and sawdust were selected for comparison. Gasification experiments were conducted on a pilot-scale fluidized bed to obtain the optimal air equivalence ratio values for rice husks, sawdust, and the briquettes of eucalyptus bark and corn stalk. The causes of slagging during biomass briquettes gasification were analyzed. Results show that the optimal air equivalence ratio value for briquettes of eucalyptus bark, rice husks and sawdust is 0.20, and the gas heating values of the three biomass are 5.5 MJ/m3, 5.5 MJ/m3 and 6 MJ/m3 respectively, the corresponding gasification efficiencies are 60%, 45% and 52%. While the optimal air equivalence ratio value of corn stalk briquette is 0.24, which means requiring more air due to the high ash content and low heating value. The gas heating value of corn stalk briquettes is 4 MJ/m3, and the gasification efficiency is 35%. The increase in gasification temperature promotes the gasification reaction of various biomass. Biomass briquettes with high concentration of alkali and alkaline earth metals are more susceptible to slagging during gasification.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Prediction Method for Biomass Gasification Product Distribution Based on Physics-informed Neural Network
    DENG Zhiping, REN Shaojun, WENG Qihang, ZHU Baoyu, SI Fengqi
    2024, 44(5): 719-726. https://doi.org/10.19805/j.cnki.jcspe.2024.240004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Machine learning methods have demonstrated promising applications in biomass gasification modeling. However, machine learning models primarily rely on experimental data and do not consider the reaction mechanisms in gasification. In situations that data samples are insufficient, there can be significant deviations between the actual correlation characteristics exhibited by the model and the mechanistic laws. Thus a method for predicting biomass gasification product distribution based on physics-informed neural networks (PINN) was proposed. This method seamlessly integrated real experimental data with prior mechanistic knowledge, embedding boundary constraints and monotonic relationships among key parameters into the artificial neural network(ANN) model. Automatic differentiation techniques were used to assist optimization, enabling efficient model training. Results show that the PINN model achieves a coefficient of determination greater than 0.89 and a root mean square error less than 4%, the overall prediction accuracy is superior compared to the three models which are purely fitting based on machine learning: random forest (RF), support vector machine (SVM) and ANN. Furthermore, the PINN model strictly adheres to boundary constraints and prior mechanistic monotonic relationship, exhibiting better interpretability and generalization capabilities.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Effect of Biomass Components on Physical Properties of Pellets
    HUANG Jiantian, ZHANG Shouyu, LANG Sen, CHEN Xuyang, ZHANG Xingjia, XU Zihang, MA Dafu, WU Yuxin, LÜ Junfu
    2024, 44(5): 727-734. https://doi.org/10.19805/j.cnki.jcspe.2024.230557
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To explore the effect of biomass components such as cellulose, hemicellulose and lignin on physical properties of pellets, cotton stalk and wood sawdust were mixed with their components at different mass ratios to prepare the pellets. The apparent density and compressive strength of pellets were analyzed by electronic universal material testing machine. The biomass molecular structure before and after briquetting was analyzed by X-ray photoelectron spectroscopy. Results show that the compressive strength of pellets is directly affected by cellulose, meanwhile hemicellulose and lignin mainly act as binders to improve the compressive strength of pellets indirectly. The addition of cellulose or hemicellulose to cotton stalk significantly increases the C—OH functional group in its pellets, and C＝C functional group is formed, which are conducive to form the intermolecular force and increase the stability of molecular structure. They can enhance the physical properties of pellets.
  • Topic on Efficient Utilization of Biomass Energy Resources
    Research on Multi-objective Optimization of a CCHP System with Solar and Biomass Complementary Based on Improved Beluga Whale Algorithm
    WANG Yaochen, WANG Xi, LIU Qi, HOU Hongjuan, XU Baoping, LI Anzhe
    2024, 44(5): 735-744. https://doi.org/10.19805/j.cnki.jcspe.2024.230547
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the problems of instability and utilization of renewable energy, a combined cooling, heating, and power (CCHP) system was proposed that integrated solar photovoltaic/thermal, water electrolysis for hydrogen production, and biomass gasification and methanation. Aiming at the capacity matching problem of the CCHP system under high dimensional target, an improved beluga whale (MOBWO) algorithm was proposed and verified. The proposed algorithm improved the distribution of solutions and the convergence rate. A case study based on this method shows that compared with the individual systems, the fossil fuel consumption is reduced by 56.8%, the CO2 emission is reduced by 53.1%, and the flexibility reaches 51.6%, although the annual total cost of the optimal capacity allocation scheme is increased by 19.8%. In this case model, the MOBWO algorithm has better solving performance than non-dominated sorting genetic algorithm-II (NSGA-2) and multi-objective particle swarm optimization (MOPSO) algorithm.
    • Power Equipment and System
  • Power Equipment and System
    Effect of Kaolin Particle Size on Ash Deposition and Sintering Characteristics of Xinjiang Coal
    TAO Li, PAN Haoxiang, LÜ Weizhi, YU Dunxi
    2024, 44(5): 745-751. https://doi.org/10.19805/j.cnki.jcspe.2024.220779
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Severe ash deposition and slagging issues have occurred during the combustion utilization of Xinjiang coal, and adding kaolin additives is an effective way to address these issues. With the sedimentation furnace ash accumulation experiments and the fixed-bed sintering experiments, the performances and mechanism for prevention and control of kaolin with different particle sizes were studied. Results show that kaolin changes the ash-forming characteristics of Xinjiang coal through its dilution and interaction with minerals in coal, which in turn affects the ash accumulation behaviors and sintering characteristics. Although fine kaolin can effectively inhibit the vapor deposition of alkaline substances through interaction, the dilution of the additives leads to a smaller ash particle size. Therefore, it is easier to form ash deposition in the initial stage. Under the combined effect of above two aspects, fine kaolin and coarse kaolin have similar prevention and control effects on the growth of ash accumulation in the initial stage. In addition, the smaller ash size distribution after the addition of fine kaolin promotes the development of ash sintering degree, which is not conducive to the soot blowing and removal of sediments.
  • Power Equipment and System
    Method of Determining Gland Seal Leakage of Steam Turbine by Introducing Intermediate Variable
    GUO Ronghe, PAN Honggang
    2024, 44(5): 752-758. https://doi.org/10.19805/j.cnki.jcspe.2024.230128
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the measurement problem of gland seal leakage of high pressure (HP) and intermedia (IP) combined turbine, a method of determining the gland seal leakage by introducing intermediate variable was proposed. And a calculation method was derived through theoretical analysis. The total amount of gland seal leakage of HP and the component of IP side gland seal leakage at different conditions were calculated by taking the leakage of IP balance piping of gland leakage as an intermediate variable. Taking a subcritical 600 MW steam turbine as an example, the calculation results were compared with the design conditions. Results show that the relative error of gland seal leakage is within 1%. Compared with the calculated values by the variable steam temperature method, the relative error of the IP side gland seal leakage is within 5%. Research results prove that the proposed method is reliable in theory and has high accuracy in calculation, also simple in operation and feasibility.
  • Power Equipment and System
    Effects of Splitter Blade Length and Circumferential Offset on the Performance of ORC Radial Inflow Turbine
    HAN Xu, LI Qi, YANG Yidong, LIU Shuhua, LI Peng
    2024, 44(5): 759-769. https://doi.org/10.19805/j.cnki.jcspe.2024.230329
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Using splitter blades can effectively improve flow blocking problem in blade channel and reduce flow loss. Aiming at an ORC radial inflow turbine with certain splitter blades, the influence of different splitter blade lengths and circumferential offset on turbine performance was studied. And internal flow conditions, blade load and loss distribution were analyzed by numerical simulation of different blade layout schemes. Results show that the splitter blade can effectively weaken the vortex in the channel, improve the flow condition, and make the pressure distribution inside the channel reasonable. At the same time,it can share part load of the main blade to a certain extent. Compared with the length of the splitter blade, the influence of circumferential offset on the distribution of entropy yield is obvious. With the increase of length and circumferential offset, the high entropy yield range and total pressure loss coefficient show a trend of first decreasing and then increasing, and the change of isentropic efficiency is the opposite. When l=0.5 and d=0.5, the isentropic efficiency is the largest by 91.26%, and the power is roughly positively correlated with blade length. When the length coefficient and circumferential offset are controlled between 0.5-0.6, the ideal flow condition and blade load distribution can be maintained, and the high entropy yield range is small, which is conducive to the improvement of turbine performance.
    • New Energy Resources and Energy Storage
  • New Energy Resources and Energy Storage
    Research Progress on Material Design of CaO/CaCO3 Energy Storage System
    PAN Yi, LIU Dunyu, JIN Jing
    2024, 44(5): 770-781. https://doi.org/10.19805/j.cnki.jcspe.2024.230219
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of inadequate cyclic stability, low thermal conductivity, and insufficient light absorption in CaO/CaCO3 energy storage system, discussions were conducted on improvement methods for the performance of calcium-based materials from the aspects of the selection of calcium-based raw materials, addition of doping elements in composite materials, and adjustment of operating conditions. Results show that inert oxides are formed within materials through the addition of elements such as Al, Mn, and Ti, which can inhibit sintering and further improve the cyclic stability of materials. The thermal conductivity of materials can be enhanced by the doping of materials with high thermal conductivity, such as Al2O3, MgO, SiO2, and ZnO. Additionally, the spectral absorption of materials can be improved by the doping of elements such as Mn, Cu, Fe, Co, and Cr. Corresponding summaries may provide a reference for the design of materials for thermochemical energy storage.
    • Digitalization and Intelligentization
  • Digitalization and Intelligentization
    Degradation State Evaluation of Wind Turbine Generator Set Pitch Bearing Based on Multivariant Refined Composite Multiscale Fluctuation Dispersion Entropy and Cumulative Euclidean Distance Matrix Measure
    WANG Xiaolong, LI Yingsheng, FU Ruiqi, HE Yuling
    2024, 44(5): 782-791. https://doi.org/10.19805/j.cnki.jcspe.2024.230232
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To solve the problems of serious environmental noise interference and low degradation state evaluation accuracy of wind turbine generator set pitch bearing during its service process, a degradation state evaluation model combining multivariant refined composite multiscale fluctuation dispersion entropy and cumulative Euclidean distance matrix measure was proposed. In this model, the feature acquisition process of monitoring data was expanded from single channel to multi-channels, and the multiscale features of multichannel monitoring data were extracted through the proposed multivariant refined composite multiscale fluctuation dispersion entropy algorithm. Then the combination of cumulative sum verification algorithm and Euclidean distance matrix measure was used to evaluate the difference between the benchmark samples and analyzed samples, and the degradation state evaluation of pitch bearing was realized. The verification results of whole life cycle accelerated fatigue experiment of wind turbine generator set pitch bearing show that the initial degradation moment of pitch bearing can be captured timely, and the whole degradation process can be accurately tracked using this proposed model.
  • Digitalization and Intelligentization
    Online Identification and Compensation of Nonlinear Characteristics of Actuator Based on Radial Basis Function Neural Network Under Hybrid Algorithm
    LIU Xinping, CHEN Yiwen, DONG Zijian
    2024, 44(5): 792-801. https://doi.org/10.19805/j.cnki.jcspe.2024.230245
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of online identification and compensation of nonlinear characteristics of actuator in the control system, a variable hybrid radial basis function (VHRBF) neural network combining variable step size kernel least mean square (SVSKLMS) and genetic algorithm was studied. The nonlinear characteristic model of actuator in the control system was established using the radial basis function (RBF) neural network, which didn't rely on the accurate mathematical model for obtaining the information of controlled objects. To solve the problem of poor identification performance of traditional RBF neural network, genetic algorithm (GA) was used to optimize the center vector and variance of neural network, while SVSKLMS algorithm was used to optimize the weight of RBF neural network model. And then the best RBF neural network was obtained. Finally, the nonlinear characteristics of actuator were identified and compensated online based on VHRBF neural network and its inverse model compensator. The simulation results show that compared with RBF neural network trained by other algorithms, the proposed VHRBF neural network can accurately identify and compensate the nonlinear characteristics of actuator with faster convergence speed and better convergence performance.
    • Green Energy and Low-carbon Technology
  • Green Energy and Low-carbon Technology
    Research on Cooperative Control Strategies for SCR Denitrification Systems Based on Deep Reinforcement Learning
    ZHAO Zheng, LIU Zihan
    2024, 44(5): 802-809. https://doi.org/10.19805/j.cnki.jcspe.2024.230221
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A cooperative control strategy of deep deterministic policy gradient (DDPG) and proportion integration differentiation(PID) based on multidimensional state information and segmental reward function optimization was proposed for the selective catalytic reduction(SCR) denitrification system with large inertia and multi-disturbance. Addressing the problem of low strategy learning efficiency of the DDPG algorithm caused by the partially observable Markov decision process (POMDP) in the SCR denitrification system, the multidimensional state information of the SCR denitrification system was designed firstly. Secondly, the segmented reward function of the SCR denitrification system was designed. Finally, a DDPG-PID cooperative control strategy was designed to achieve the control of SCR denitrification system. Results show that the designed DDPG-PID cooperative control strategy improves the strategy learning efficiency of the DDPG algorithm and the control effect of PID. Meanwhile, the designed cooperative control strategy has strong set value tracking capability, anti-interference capability and robustness.
  • Green Energy and Low-carbon Technology
    Low-temperature Catalytic Generation Characteristics of SO3 on a Large Pilot Denitrification Platform
    LI Wentao, XIAO Haiping, HONG Chunxue, LIU Yi, HAN Zhenxing
    2024, 44(5): 810-816. https://doi.org/10.19805/j.cnki.jcspe.2024.230234
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the SO3 generation characteristics of SCR system during low temperature operation, the effects of flue gas temperature, SO2 mass concentration and ammonia injection on the catalytic SO3 generation characteristics were analyzed on a pilot test bench. Results show that temperature is the main factor affecting the SO3 generation rate. SO3 generation rate decreases as the flue gas temperature decreases,which is also influenced by SO2 mass concentration. However, the effect of SO2 mass concentration on SO3 generation rate becomes very little when the inlet flue gas SO2 concentration is in the range of 700 to 1 150 mg/m3 and temperature is below 260 °C. Compared with the un-injected ammonia condition, both the outlet SO3 mass concentration and SO3 generation rate decrease under ammonia injection condition. At the same time, the probability of low-temperature corrosion decreases, and the probability of ammonium bisulfate generation increases. Since SO3 generation rate in the SCR system decreases at low temperature, the harm to the low-temperature heating surface is reflected in the low-temperature corrosion and blockage under the synergistic effect of H2SO4 and ammonium bisulfate.
    • Integrated Energy System
  • Integrated Energy System
    3E Analysis of a Novel Medical Waste Gasification Polygeneration System with 'Carbon Peak' and 'Carbon Neutrality' Goals
    KONG Mengdi, YE Xuemin, LIU Di, LI Chunxi
    2024, 44(5): 817-826. https://doi.org/10.19805/j.cnki.jcspe.2024.230275
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the conventional medical waste gasification polygeneration system (conventional scheme), two low-carbon schemes 1 and 2 coupled with carbon capture and storage (CCS) were proposed. The three schemes were compared from the viewpoints of energy, exergy and economy (3E). The exergy analysis of optimal scheme 2 was carried out, and the impact of exhausted gas recirculation (EGR) on system performance was discussed. Results show that the overall exergy efficiency of scheme 2 is increased by 7.18% with 15.38% reduction in net power generation efficiency compared with conventional scheme. The dynamic payback period (DPP) of low carbon scheme 2 is 3.12 years less than that of scheme 1, and the net present value (NPV) is increased by 5.906 0 million yuan. Scheme 2 can ensure the excellent performance of the system and achieve the goal of low carbon emissions with significant economic benefits. Meanwhile, increasing the exhausted gas recirculation ratio can enhance the economic benefits of the integrated system.
  • Integrated Energy System
    Thermodynamic Analysis of the Organic Rankine Cycle Driven by Saturated Steam from the Hazardous Waste Incinerator
    ZHANG Manzheng, WU Suriguga, XIAO Meng, YAN Peiwei, MIAO Zheng, JI Xianbing, XU Jinliang
    2024, 44(5): 827-836. https://doi.org/10.19805/j.cnki.jcspe.2024.230181
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Heat generated during the incineration of hazardous waste is usually used to produce saturated steam to supply steam, heat and other needs for industrial parks, which can also be used for low-temperature power generation. The thermodynamic performance of the saturated steam-driven organic Rankine cycle (ORC) system was analyzed. Based on thermal matching analysis of the steam latent heat source and the ORC system under the basic working condition, three optimization measures were proposed, and the thermodynamic performances of the system with single optimization or combined optimization measures under different working conditions were studied. Results show that the combined optimization method can make the system achieve better performance, and the maximum net output work is 3 193.81 kW, which is increased by 170.46% compared with the basic working condition. Accordingly, the thermal efficiency is 23.34% with an increase of 30.25%, and the total exergy efficiency is 66.25% with an increase of 41.80%.