The Research On Cogeneration And Waste Heat Recovery Of Flue Gas Of A Regional Boiler Room In Ji Nan

A district heating boiler room in Jinan is equipped with two 75t/h medium temperature and medium pressure steam boiler.After the temperature and pressure reduction,the steam produced by the boiler is delivered to the surrounding area,undergoing heat transfer with water and the hot water is used by the heat consumers.The heating cost of district heating boiler room in Jinan has remained at a high level,and energy saving and emission reduction is imminent.In this paper,energy consumption analysis,energy saving renovation and the energy saving technology of boiler room were discussed.Firstly,by the analysis of the form of heating system and the energy consumption statistics in the past three years,boiler positive and negative balance efficiency experiment and tracking data for smoke in 58 consecutive days,the present status of energy consumption for boiler room was analyzed based on energy analysis method.It was found that the low operating efficiency,unreasonable heating system inducing the waste of steam capacity for work,large transmission network loss,the waste of condensed water and direct discharge of flue gas caused the high energy consumption.So,the boiler room had great potential for energy saving.The goal of energy saving and consumption reducing could be realized in such three aspects as heat and power cogeneration,the first exchange station construction and recovery of waste heat from flue gas.Secondly,the cogeneration scheme and the scheme of first exchange station construction were presented for the boiler room,and it gave a detailed exposition from aspects of equipment selection,system design and economic benefits.Through the estimation of economic benefit of cogeneration transformation,the payoff was 39361 thousand yuan annually while the payback period was only 0.21 years.The returns on energy conservation of condensed water recovery by increasing first exchange station was as high as 14240.7 thousand yuan annually,and the payback period was 1.16 years.Additionally,the principle of energy analysis was introduced and it was considered that the energy saving effect could be further studied according to the analysis of exergy efficiency.The system model was established according to the corresponding scheme.The energy saving effect of small scale cogeneration were also analyzed and discussed based on exergy analysis.Finally,the thermodynamic analysis and technical research on the utilization of waste heat in medium and low temperature flue gas were carried out.Through calculation and analysis on energy saving rate of the three schemes of flue gas waste heat recovery in common use,it was concluded that the heat energy of flue gas could be transferred to different working media through various heat exchange equipment to achieve energy saving effect.The detailed scheme of flue gas waste heat recovery and the project implementation plan were put forward.In addition,the economic benefit estimation was carried out.The returns on recovering heat was as high as 1658.9 thousand yuan annually,and the payback period was 3.32 years.