以LiBr-NH4Br-H2O为工质对的新型AHT循环的研究

从优化工质对的角度出发,基于盐析结晶的原理,实验研究了NH4Br对吸收溶液的LiBr饱和浓度、蒸汽压、以及AHT循环性能的影响。结果表明,NH4Br对LiBr具有明显的盐析作用,该作用随着冷却结晶温度的上升而增强。在冷却结晶温度50℃的情况下,NH4Br在上清液中的质量分数达到6.8%时,其盐析作用达到最大,此时LiBr在上清液中的质量分数从无添加的65.3%下降到了60.1%,上清液饱和蒸汽压也有了明显的增大。对于该新型AHT循环,采用LiBr-NH4Br-H2O工质对,较之LiBr-H2O工质对,可进一步降低对投入发生器余热品位的要求,降幅达到6℃左右。

Working pairs of LiBr -NH4Br- H2O based on a new AHT cycle

From the perspective to optimize the working pairs, investigated experimentally the effect of adding NH4 Br as a salting - out agent on the saturated concentration and vapor pressure of LiBr absorp- tion solution, furthermore the performance of a new AHT cycle, based on the both principles of the AHT cycle and salting - out crystallization. Results show that NH4 Br has an obvious salting - out effect on LiBr, which enhances with increasing crystallization temperature. NH4 Br show the greatest salting - out effect when its concentration reached 6. 8% in the supornatant at 50℃. Under this condition, the saturated concentration of LiBr was down to 60. 1% from that of 65.3% without adding NH4Br, correspondingly, the vapor pressure of supematant increased significantly. As a result, the required temperature of waste heat as the driving source of generator in the new AHT cycle can be pulled down about 6℃ by using LiBr - NH4Br - H20 instead of LiBr - H20.