Abstract:Focusing on the'two to one'gas steam combined cycle cogeneration unit of a certain gas-fired thermal power plant,investigating the uniformity of the flue gas flow field in the selective catalytic reduction(SCR)denitrification system of the waste heat boiler,and using computational fluid dynamics(CFD)methods,exploring the control effect of adding a guide plate group on the flue gas flow field.The results show that the guide plate group can guide the direction of flue gas flow,weaken local vortices,and significantly optimize the uniformity of the flue gas flow field.When no guide plate group is added to the key section upstream of the catalyst,the coefficient of non-uniformity(Cv)of flue gas velocity distribution is 30.35%,indicating the problem of local flow velocity being too high or too low.After adding a guide plate group and optimizing its angle,spacing,and arrangement position,the Cv of the section decreased to 14.62%,and the uniformity of the flow field is improved by over 50%.

Abstract:Based on the existing thermal physical parameters of rocks and soils,the shallow geothermal energy reserves and the area available for heating and cooling within the Qiannan Prefecture region are estimated,and the suitable areas for development and utilization are qualitatively evaluated.The results show that the total heat capacity of geothermal energy beneath 200 m on the surface of Qiannan Prefecture is 7.75×1015 kJ/℃.The total heat exchange power in summer is approximately 2.450 billion kW,and in winter it is approximately 2.780 billion kW.The area available for heating in winter is approximately 55.600 billion m2,and the area available for cooling in summer is approximately 35.000 billion m2.Among them,the urban basin of Huishui and the Dushan basaltic karst basin are typical areas for the development and utilization of ground heat source heat pump systems and groundwater heat source heat pump systems,and two characteristic development and utilization models can be established,further promoting the regionalized development and utilization of shallow geothermal energy in the karst area of Southwest China,and helping to achieve the regional'double carbon'goals.

Abstract:In response to the problem of high energy consumption and serious waste of exhaust heat in the ventilation of a comprehensive pipe gallery,taking the standard ventilation section of an underground comprehensive pipe gallery power room in Jining City as the research object,conducting on-site testing and analysing of the winter exhaust temperature characteristics,proposing a heat pump system based on the utilization of exhaust waste heat in the comprehensive pipe gallery,and exploring its heating performance.The results show that when the outdoor air temperature dropped to-11.2℃in winter,the exhaust temperature remained at 13.0℃,and the exhaust temperature increased by 24.2℃.Compared with conventional air source heat pumps,the exhaust waste heat utilization heat pump system has an average coefficient of performance(COP)increase of 26.7%during the heating season.When the additional power consumption of the ventilation fan is not considered,the power consumption can be reduced by as much as 21.1%.Even if the additional power consumption of the 1.0 kW ventilation fan is included,the power consumption can still be reduced by 13.0%.The energy-saving effect is significant,and it can effectively avoid the technical problems of conventional air source heat pumps such as frosting and heating capacity degradation at low temperatures.

Abstract:In response to the upgrading requirements for the secondary Ⅳ-class effluent of an industrial wastewater treatment plant,in order to meet the surface water Ⅳ-class standards of chemical oxygen demand(COD)≤30.00 mg/L and ammonia nitrogen≤1.50 mg/L,the'aerated biological filter+powdered activated carbon adsorption'process is adopted for enhanced treatment.The results show that the effluent COD is stabilized at 22.00～24.00 mg/L after the renovation,and ammonia nitrogen is lower than 1.00 mg/L under winter low-temperature conditions,both of which were superior to the target limits,achieving a balance between stable compliance and effective operation cost.

Abstract:Taking the condensing gas-fired boiler as the research object,through methods such as establishing thermodynamic models,the operating and emission characteristics of the gas-fired boiler under the hydrogen blending ratio ranging from 0 to 100%are studied.The results show that under the condition where the boiler's output heat load and theoretical combustion temperature remain unchanged,as the proportion of natural gas blending with hydrogen increases,the radiation heat exchange ratio in the furnace rises,the heat exchange capacity of the condenser significantly increases,and the overall thermal efficiency of the boiler based on lower calorific value increases from 102.08%to 103.55%,with an increase of approximately 1.3%.The overall thermal efficiency of the boiler based on higher calorific value increases from 93.24%to 89.14%,with a decrease of approximately 4.4%.The NOx emission volume decreases from 69 mg/m3 to 24 mg/m3,a reduction of approximately 65.22%.The volume fraction of CO2 decreases from 8.90%to 0.

Abstract:A method for dynamic aggregation and regulation management of large-scale resources in a virtual power plant(VPP)is proposed.By determining the peak periods,off-peak periods,and normal periods of regional electricity consumption,the power system load demand data,flexible load characteristic data,and price data for each period are obtained.The operation objective function of VPP under the market mechanism is proposed,and its participation in the market operation mechanism is established.The types of flexible resources are identified,and a multi-flexible resource dynamic aggregation model of VPP is constructed.The improved wolf pack algorithm(WPA)is used to optimize the satisfaction factor of the satisfactory decision.The results show that compared with traditional methods,the improved WPA algorithm can significantly reduce costs,enabling VPP to meet electricity demand through gas turbines and energy storage equipment during peak periods,thereby enhancing the flexibility and economy of the power system.

Abstract:The rotary kiln is the core equipment in the production of asphalt coke.Its combustion process integrates multiple physical fields such as flow,heat transfer,mass transfer and the rotational motion of materials,as well as chemical reactions,and is a typical complex coupled process.Considering the influence of physical and chemical reactions on the heat transfer process inside the kiln,for a rotary kiln with a length of 55 m,a one-dimensional axial comprehensive heat transfer mathematical model is established to analyze the heat transfer law under the reverse flow of gas and materials inside the kiln.A material volatilization analysis model and a material layer heat transfer model are constructed,and the volatilization rate curve and the temperature distribution curve of the material layer are obtained through calculation.The results show that the volatilization rate is the highest at approximately 15 m from the kiln tail,and the temperature of the material layer reaches the highest at approximately 38 m.

Abstract:In response to the severe hydraulic imbalance and high electricity consumption of the centralized heating system in a certain residential area of Tianjin City,a simulation model is established using the Viheating hydraulic calculation software to compare and analyze the operating characteristics of the jet pump system and the original balance valve system.The results show that the jet pump system can reduce the frequency of the circulating pump to 26.00 Hz,decrease the flow by approximately 50%,reduce the head by approximately 59%,and lower the power of the circulating pump from 25.07 kW to 7.36 kW.During the heating season,it can save 64 250 kWh of electricity and the investment recovery period is 6.16 a.The jet pump technology can effectively solve the problem of hydraulic imbalance in the secondary network,achieve the goal of energy-saving and emission reduction,and has good economic and social benefits.

Abstract:Based on the remote sensing image data of land use in the Chengdu-Chongqing urban agglomeration from 2000 to 2020 for five periods,the urban form is quantified.The spatial econometric model is used to analyze the impact of urban form on carbon emissions.The results show that from 2000 to 2020,the carbon emission volume of the Chengdu-Chongqing urban agglomeration increased from 154.72 Mt in 2000 to 439.28 Mt in 2020.Spatially,it presented a bipolar pattern with Chengdu and Chongqing as the core.There is a significant correlation between urban form and carbon emissions.For every 1%increase in the area of urban patches and the maximum patch index,the total carbon emissions in the region will increase by 2.642%and 4.600%,respectively.For every 1%increase in the percentage of similar adjacent areas,the total carbon emissions will decrease by 7.600%.

Abstract:Taking residential buildings in Shandong Province as the research object,exploring their spatiotemporal evolution as well as future development trends.Based on the calculation of carbon emissions from residential buildings in Shandong Province from 2000 to 2021,the spatiotemporal evolution characteristics of carbon emissions from residential buildings at the municipal and county levels in Shandong Province are analyzed using night-time light inversion.Feature selection is conducted using Pearson-RF,and the STIRPAT model and scenario analysis are employed to predict the carbon emissions from residential buildings in Shandong Province.The results show that the carbon emissions from residential buildings in Shandong Province are continuously increasing,with regional differences and spatial correlations existing within the system.Only under the low-carbon scenario,carbon peak(peak of 14 151.43 million t)can be achieved in 2030.It is recommended to achieve the emission reduction targets by measures such as controlling building scale,promoting green renovations,and formulating differentiated regional policies.

Abstract:For the optimization of operating parameters of the top-floor radiation cooling coupled with fresh air supply system,a multi-objective optimization and decision-making method is proposed.The non-dominated sorting genetic algorithm(NSGA-Ⅱ)is applied,with system energy consumption and the expected dissatisfaction percentage(PPD)as the objective functions for optimization.Pareto optimal solution sets under different personnel numbers are generated,and the entropy weight-approaching ideal solution sorting(EW-TOPSIS)decision-making model is introduced to objectively determine the global optimal configuration.The results show that in the low-load condition with 3 people and the high-load condition with 7 people,energy consumption is the dominant factor in decision-making,with weights of 0.70 and 0.76,respectively.While in the medium-load condition with 5 people,the importance of thermal comfort increases,with a weight of 0.32.After optimization,the system tends to adopt a higher supply water temperature and a lower supply water flow rate,and adjusts the supply air temperature and supply air volume to cope with different load changes,providing a reference for the energy-saving and comfortable operation of the radiation air conditioning system in variable working conditions.

Abstract:Accurately predicting the process parameters of oil receiving and dispatching in the crude oil depot and selecting the appropriate heating process scheme is of great significance for reducing the energy consumption of oil depot operation and improving operational efficiency.Based on the principles of heat transfer and fluid mechanics,a steady-state simulation model including components such as pipelines,heating furnaces,and storage tanks is constructed.The solution is obtained by using the node-component association matrix method and the Broyden iterative algorithm,and by utilizing the self-developed large-scale crude oil depot process simulation software.Establish a total energy consumption calculation model,analyze the energy consumption of the two heating processes,'furnace first then tank'and'tank first then furnace',under different environmental temperatures and storage periods,and propose a heating process selection strategy based on environmental temperature and storage period.The results show that,verified through a case of an oil depot in the north,the relative deviations of the model's predictions for pressure and temperature are respectively lower than 5.96%and 3.92%.When the environmental temperature is-25℃and the storage period is 10 d,the'tank first then furnace'process can save 26.80%of energy.

Abstract:For the organic waste liquid and waste gas generated by a certain enterprise,a thermal insulation incineration disposal scheme is proposed.The mixed low calorific heat of the waste liquid and waste gas is calculated using the element mixture analysis method.The detailed structural design of the vertical thermal insulation incinerator is completed,and the actual operation adjustment of the incinerator is carried out based on the temperature rise curve combined with the staged air distribution technology.The results show that the mixed fuel can achieve self-sustaining combustion at around 1 100℃,with the flue gas temperature remaining stable at 1 100℃to 1 200℃,and the pollutants are discharged in compliance with standards.

Abstract:Driven by information technology,energy-saving optimization of factory air conditioning systems has become a important link in improving energy utilization efficiency.Based on the measured data of a certain manufacturing factory,the energy consumption proportion composed of units such as the refrigeration main unit,air system and water system in the air conditioning system is analyzed,and the collaborative control path of operation data collection and central dispatching is proposed.The results show that the system coefficient of refrigeration performance(COP)has increased from 3.2 to 4.1,the energy consumption per unit capacity has decreased by 21.8%,and the alarm frequency has decreased by 75%.Informationization strategies have obvious potential for energy-saving and stability improvement,and can provide an optimized path for industrial energy systems.

Abstract:In response to the problems such as high costs and low efficiency in the traditional asset management model under the growth of power demand,an unmanned power intelligent supervision information platform is constructed.The platform adopts technologies such as internet of things,artificial intelligence,computer information and remote monitoring,and is based on a hierarchical architecture of the perception layer,network layer,platform layer and application layer.It integrates functional modules such as asset maintenance,intelligent inspection,fault elimination,accident repair,upgrading and transformation,energy efficiency management and automatic generation of operation reports,and analyzes it based on a certain park.The research shows that the platform can achieve scientific operation,energy-sving and cost reduction,significantly reduce costs,and ensure the continuity,stability and safety of power supply.

Abstract:The traditional air conditioning system for clean operating rooms has problems such as coupled temperature and humidity control and excessive energy consumption.It is urgent to explore efficient and energy-saving control schemes.A temperature and humidity independent control(THIC)system scheme is constructed,where fresh air takes on the moisture load and the circulating unit operates in dry conditions to achieve separate control of temperature and humidity.The system configuration and air treatment process are established,and an energy-saving analysis is conducted using a hospital in Yingtan,Jiangxi Province as the research object.The results show that compared with the traditional scheme,the total cooling capacity of the THIC system is reduced by 46.2%,the reheat capacity of the circulation unit is reduced by 88.7%,and the annual electricity consumption of the first-level operating room is reduced by 52.3%,with a carbon dioxide reduction of 3.2 tCO2 per year.The temperature and humidity independent control system effectively avoids the phenomenon of cold and hot counteraction,significantly improving air quality and energy-saving effect,providing a technical approach for the green development of medical buildings.

Abstract:Carbon dioxide capture and storage(CCS)technology,as an important means to address global warming,has been widely adopted in China.However,during its promotion process,this technology faces challenges such as insufficient technical maturity,high investment costs,and potential environmental leakage risks.To address the safety challenges in the promotion of CCS technology,taking a 400 000 t/a CCS pilot project of a certain company as the research object,considering the safety requirements of ground capture,pipeline transportation,and underground storage,the hazard and operability study(HAZOP)method combined with the company's risk matrix is adopted to comprehensively assess the process parameters and equipment operation risks at the design stage from multiple dimensions,and improvement plans and measures are formulated for different risks.Specific HAZOP analysis results are obtained,and targeted intervention measures are proposed.The research results can provide references for the subsequent revision of operation procedures,formulation of employee training plans,and supplementation of hidden danger governance measures for the project.

Abstract:Due to the increase in heavy oil prices and the proposal of the'double-carbon'goal,designing dual-purpose burners for oil and gas and enabling 100%load switching for both oil and gas usage has become a preferred choice for some petrochemical users.Based on the principle of calorific value equivalence,a 4-flame swirl burner structure is adopted,and the oil nozzle is designed using bubble atomization technology,the common air supply system is utilized to enable the free switching of the fuel.The results show that the efficiency of the 40 t/h boiler is 91.8%in the oil mode and 93.5%in the gas mode.The steam temperature,pressure,and evaporation volume all meet the design requirements,and the range of oil nozzle atomization steam consumption has been calibrated.The burner enables 100%load-free switching of oil and gas,allowing for flexible selection based on fuel prices,saving fuel costs,and having good economic,safety,and environmental performance.

Abstract:To explore the influence of the selection of mixed working fluids on the performance of the cascade heat pump system,the working principle of the cascade heat pump is systematically elaborated,and the screening process of mixed working fluids is described.The model of the cascade heat pump is designed and simulated using Matlab,and the REFPROP software is called to analyze the effects of factors such as condensation and evaporation pressures,compressor power consumption,mass fraction,and intermediate condensation temperature of different mixed working fluids on the energy efficiency ratio(COP).The results show that the application of 3 types of mixed working fluids increases the condensation pressure by 8.60%to 25.40%and the evaporation pressure by 8.70%to 26.23%.When the mass fraction of R134a is 10%,the compressor power consumption of the R134a+R152a combination is lower,at 24.26 kW.Compared with the other 3 groups of working fluids,the COP of the R152a+R1234ze combination is higher,reaching 3.27.For the cascade heat pump system,different mixed working fluids have specific optimal intermediate condensation temperatures,and the R152a+R1234ze combination has the lowest power consumption of 48.28 kW.As a low-temperature-level mixed working fluid,R152a+R1234ze always maintains the maximum COP when the low-temperature evaporation temperature and high-temperature condensation temperature change.

Abstract:In response to the problems of complex coupling of operating parameters in central air conditioning refrigeration systems,strong reliance on traditional manual parameter adjustment experience,and the tendency of single intelligent algorithms to fall into local optima,resulting in poor energy efficiency optimization effects,a new energy-saving optimization method based on multiple genetic algorithms(MGA)is proposed.Through grey correlation analysis(GRA),three key influencing parameters,namely the outlet water temperature of the main unit,the frequency of the chilled water pump,and the frequency of the cooling water pump,are selected from 10 parameters.The backpropagation(BP)neural network is used to construct an energy efficiency ratio(EER)prediction model with a prediction error of less than 0.4%as the fitness function.The parameter association rules mined by the association rule algorithm(Apriori)are introduced as constraints.The MGA is used for global optimization.The results show that under a load rate of 80%to 90%in a commercial building,the method increases the system energy efficiency ratio by an average of 5.75%and up to 7.93%,effectively improving the system operation efficiency.