| In recent years,with the reform of power enterprises and the increasing of pressure on energy conservation and environmental protection,the capacity of small and medium-sized unitsa with 200MW and below are being eliminated gradually.On the other hand,many thermal power units with the capacity of 200MW and below still bear the arduous task of heating the urban residents.How to ensure the citizens’ heating requirement and achieve the aim of energy saving and emission reduction?It’s a practical measure of High back pressure heating transformation technology,many domestic units have implemented the technology of high back pressure heating transformation.There has been two 135MW Condensing Unit in Zhangqiu Power Plan engineering project,in August and December 2002 put into operation respectively,and capacity transformation for the 145MW unit in 2005.In order to increase the heating capacity,improve the economy of the heating,has been carried out double rotor double back pressure technology heating transformate.Putting 145MW steam turbine and 335MW steam turbine joint heating,the 145MW steam turbine use low vacuum circulating water heating.The middle and low pressure connecting pipe carries on the circulating water achieve secondary heating,the 335MW steam turbine adjustable extraction steam perform the third heating to recycled water,turn into large heat source include the two sets unit of high back pressure circulating water heating in addition Condensation unit extract steam heating.This mode of large heat source of the steam turbine combined heating operation,it is the first time use double-rotor and double back pressure circulating water of heating unit.This paper deals with the combined large heat source,analysis the structural,thermal system characteristics and adaptive transformation of various related equipment of the unit,thereby obtaining such a large heat source has the following characteristics:(1)Strong heating capacity,it can meet the demand of the heat load demand of large heating network;(2)It has a strong capacity of participate in the peak of the heating network,can bear the heat of the heat load a wide range of fluctuate;(3)It can send a variety of heating parameters of the heat medium,to meet the different needs of variety of heating network and various heat loads;(4)It has a high economy.Circulating water supply and extraction steam heating can be realise cold source loss is zero use of steam power cycle.(5)It can be achieve long-distance transport of the heat.(6)Beneficial to cogeneration enterprise participate depth peaking of the Power grid,widening the scope of application of cogeneration units.The heating method discussed in this paper has used high back pressure circulating water,which can make full use of the latent heat of vaporization of low-pressure cylinder in 145 MW unit to heat the circulating water in hot wire,recycle the loss of cold source and improve the cycle efficiency of the unit.After the implementation of transformation in the unit using high back pressure heating technology,during the heating operation in winter,coal consumption of the unit can be reduced from 340g/kWh to 160g/kWh,so energy saving effect is obvious.Without increasing the size of the unit,an increase of 5 million square meters of heating area in every unit can replace the small boilers and small coal stoves in heating area,which have low efficiency,high energy consumption and high pollution.In this paper,the heating source of Zhangqiu for the eastern part of Jinan is taken as the object of study,and the operation law of cross-regional and long distance heating is explored.The distance of the whole heating pipe network is 38 km,and the pipes,which are equipped with primary relay station,are buried directly underground without compensation.After running debug and optimized operation,the system is stable and reliable.With this enormous heating source,this paper has carried out the adaptive heating process of the heating network.Based on the regional characteristics of this heating source point,the first cross-regional heating operation is carried out,which can realize the two heating circulating water systems of Zhangqiu and Jinan run safely and stably,in addition,the two systems are capable of being separated and operate separately during the heating stabilization period.In the beginning and the end of heating process,when circulating water flow and heat load of single heating station is low,it can be ensured that the high back pressure heating unit can run safely,and the unit load reaches the rated load.Thus high back pressure heating unit and heating station will start and stop at the same time.After#1 and#2 unit high back pressure transformation of Zhangqiu Power Plant,during high back pressure operating,the cool water tower and the circulating pump exit running,the unit generating water consume is reduced.This paper analyzes the phenomena and causes of the industrial backwater to the#2 cold water tower during the high back pressure operating,combined with the actual operating of the unit,Optimized the system.After transformation,put#2 machine all of cold water tower overflow water recycling,reduce the unit power consumption,during high backpressure operation,the single unit recovery of auxiliary cooling water 5000 tons everyday,the whole plant power consumption reduced 3.50 tons/kWh,the heating season recovery auxiliary cooling water 600000 tons,improving the quality of circulating water at the same time,saving water resources,it has achieved remarkable results,security benefits and economic benefits Significantly.Through research,obtained parameter variation rule and operation control method of the double unit High Back Pressure Circulating Water Heating together with unit pumping steam heating to achieve cross-regional dual thermal network operation.It has a demonstration significance for the same type of large-scale heating network to achieve large regional heating,widen the heating range and developing the cogeneration business. |
PDF Full Text Request