串联补燃型吸收式换热机组最大供热能力分析

Analysis of maximum heating capacity of series-type supplemental fired absorption heat exchanger

为进一步降低供热热力站一次侧的回水温度,增大供热量,采用串联补燃型吸收式换热机组代替常规单段吸收式换热机组.在仅考虑可行性传热端差的技术制约条件下,通过分析串联补燃型吸收式换热机组内各传热部件的热力循环过程及传热过程,建立机组的数学模型并采用迭代的数值方法进行求解,定量分析了在满足换热站设计要求的一次侧供水温度,二次侧供、回水温度条件下,一次侧回水最低温度、机组最大供热能力以及机组内换热量的分配规律.研究结果表明:在一次侧供水温度为110℃,二次侧供、回水温度为60/45℃时,串联补燃型吸收式换热机组的一次侧回水最低温度为22℃,管网输送能力是传统110/60℃水-水板式换热器的1.76倍,供热量是传统水-水板式换热器的2倍;对于常规单段吸收式换热机组而言,一次侧和二次侧的供水温度对其扩大系数基本没有影响,其值约为1.5.在一次侧供水温度为100℃,二次侧供、回水温度为69℃/54℃时,补燃型吸收式换热机组的扩大系数最大约为3.3.

To further reduce the outlet temperature of the primary water and increase the transmission capacity of the heating pipe network, the series-type supplemental fired absorption heat exchanger was used at the heat station of central heating system to replace the conventional single-segment absorption heat exchanger. In this study, with the technical constraints of feasibility of heat transfer terminal difference considered only, by analyzing the heat transfer process and thermodynamic cycle of each heat transfer component in series-type supplemental fired absorption heat exchanger, the mathematical model of the unit was established and solved by iterative numerical method, and the temperature conditions of primary water inlet, secondary water inlet and outlet satisfying the design requirements of heat exchanger station were quantitatively analyzed. The distribution rules of the minimum temperature of primary water outlet, the maximum heat supply of unit, and the heat transfer in unit were discussed. Research results show that when the temperatures of the primary water inlet was 110℃, the secondary water inlet and outlet were 60/45 ℃, the minimum temperature of the primary water outlet of the supplemental heat exchange unit was 22 ℃. The conveying capacity of the pipe network was 1.76 times of a conventional 110/60 ℃ water-to-water heat exchanger and the heat supply was twice of a conventional water-water heat exchanger. For conventional single-stage absorption heat exchangers, the primary and secondary water supply temperatures had little effects on the expansion coefficient, which was about 1.5. When the primary water inlet temperature was 100 ℃ and the secondary water inlet/outlet temperature was 69/54 ℃, the maximum expansion coefficient of the supplementary combustion absorption heat exchanger was about 3.3.