| The substitution of coal-fired boilers by thermal power plants and gas heat sources in northern China is one of the effective ways to realize clean heating in cities and towns.Accelerating the elimination of heating and industrial coal-fired small boilers in Beijing,Tianjin,Hebei and surrounding areas is the top priority in implementing the action plan for air pollution prevention and control.Zhangjiakou City,Hebei Province,is the host city of the2022 Winter Olympic Games.Clean substitution of coal-fired heating and atmospheric control are also related to people's livelihood and international impact.This paper studies the centralized heating mode of heat and power plant and gas-fired boiler instead of coal-fired boiler and the decentralized heating mode of small coal-fired boiler and the optimization scheme of large drop heating system in the Eastern District of Zhangjiakou Bridge with complex terrain,and traces the actual measurement and analysis to provide technical support for clean substitution of coal-fired heating in the host city of the International Winter Olympic Games and for solving the key problems of large drop heating,and for similar centralized heating.The scheme design provides a reference.Based on the analysis of heating status and heating development planning of existing coal-fired boilers and small bulk coal boilers in Qiaodong District of Zhangjiakou City,the topographic height distribution of heat users,heat stations and heat sources is obtained,and the difference between the highest point heat users and the lowest point heat sources in the heating area is as high as 198 m,which is much higher than the pressure-bearing capacity of conventional heating equipment.The Heating load and heat consumption of three different heating modes of thermal power plants and gas-fired boilers are analyzed and compared,that is,the independent heating mode of thermal power plants,the zonal heating mode of thermal power plants and gas-fired boilers,and the mode of interconnected heating between thermal power plants and peak shaving gas-fired boilers.It is concluded that the annual heat consumption of independent heating mode in thermal power plants is 47% more than that of heating,and that of sub-regional heating mode in thermal power plants and gas boilers is 38% more than that of heating.The annual heat consumption of combined heating mode in thermal power plants and gas peak shaving boilers is the least,which is 6%.The pressure conditions of three different heating systems under the heating mode of thermal power plant and gas peak-shaving boiler are analyzed,that is,the thermal power plant is connected with the thermal power plant and the gas peak-shaving boiler and heated by the primary heat exchange station;the thermal power plant is connected with the gas peak-shaving boiler through the pressure insulation heat exchange station and the secondary heat exchange station;the thermal power plant is heated by the primary heat exchange station after the relay pump station is connected with the gas peak-shaving boiler.The results show that the dynamic pressure of the first type of heating system exceeds the design pressure by12.8%;the second type of pressure isolation heat exchange station can solve the problem ofoverpressure,but its position should be set as low as possible when the pipe network after the pressure isolation heat exchange station is not overpressure;the third type of relay pump station can also solve the problem of overpressure.The higher the terrain,the lower the pressure requirement of the pressure pump,but the higher the position of the pressure pump,the higher the capital of some heat stations will be caused.The pressure head does not meet the requirements.Based on the application of heat supply schemes for thermal power plants and gas peak-shaving boilers,it is shown that the pipeline network is safe to operate.At the same time,when the network entry rate is low,gas peak-shaving boilers are used for heating at the beginning and the end of the heating period.In the cold period,thermal power plants bear the basic load,and gas peak-shaving boilers bear the peak-shaving load,which is more energy-saving. |
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