Experimental Study On The Charging Characteristic Of Double Steam Accumulator System

As an important steam power equipment---boiler, its operation on security and stability have an significant sense for industrial production and daily life. In industrial production,when the boilers supply steam for the outside, the process is often accompanied with some issues, such as a frequent fluctuations in thermal load, momentary large consumption of steam,hot steam intermittent for users and steam supply interruption caused by emergency. These problems will lead a lower thermal efficiency for boilers and production declined on both quality and quantity .To improve the operating economy efficiency, a steam accumulator is introduced in the boiler system.In this paper, a double steam accumulator charge system is used as the research object.After a deep understanding on the internal system, we conduct a large number of experiments.The main research contents include: The heat accumulator charging with cold start and hot start, and single and continuous steam charging and exhausting experiments with different load. Through the analysis of the change rule about the internal pressure of the accumulator and the change of the temperature of the working fluid, the charging characteristics of the accumulator were obtained. The factors that affect the stability of the process system are studied, and the control strategy for the stability of the steam accumulator is confirmed.Through the analysis of the system pressure fluctuation about the indirect and direct alternating continuous charging and exhausting experiments of the double heat accumulator,the regularity of the stability of the charging process is obtained.The results showed that: In the process of continuous charging, the internal steam temperature of steam accumulator is always higher than the water temperature , and temperature changes lag behind pressure changes. When charging begin (finish), Bypass(Charging) regulating valve closing lag and charging (bypass) regulating valve first open limit affects the main-tube pressure together. When the lag time is longer, the system’s pressure drops more; and the lower the first open limit is, the smaller the pressure drop. And the control strategy of this system is obtained: closing lag time and the first open limit of 1#charging valve are 1s and 25%、closing lag time and first open limit of 2# charging valve are Os and 15%、closing lag time and first open limit of bypass valve are 1s and 20%. In the process of continuous alternating charging and exhausting of double steam accumulator,When the regulating valve is switched on, the pressure of the main pipe appears to fluctuate,then the superheated steam pressure and steam drum pressure also appeared in varying degrees of fluctuations. In the process of indirect alternating continuous charging and exhausting, The longer the time interval under the same load, the smaller the pressure fluctuation; Under the same time interval, the flow rate of the steam supply is greater, the greater the pressure fluctuation. The stability of the indirect alternating continuous charging process is higher than that of the direct alternating continuous charging process. The research results have reference value for the design and stable operation of the steam supply system.