高温工况燃气爆炸下限工程预测方法探讨

Discussion on Engineering Prediction Method of Lower Explosion Limit of Combustible Gas Under High Temperature Working Conditions

获得特定工况下燃气的爆炸下限,是开展爆炸风险评估及爆炸防治的基础。现有研究已经基本理解了温度对燃气爆炸下限的影响规律,但还缺少可便捷用于预测高温下不同类型燃气爆炸下限的工程方法。基于文献中给出的常压时不同类型燃气在不同温度时的爆炸下限测试数据,提出由参考温度T0时的爆炸下限LELT0预测高温T时爆炸下限LELT的关系式:(LEL_(T)/LEL_(T0))=1.3~0.3(T/T_(0)),适用范围为1≤T/T0≤2、T≤723 K。将预测结果与文献实验结果对比发现,预测结果均低于实验结果,在工程应用时偏于安全。当T/T0在1~1.5范围内时,预测结果相对误差均在-6%以内,具有较好精度。当T/T0在1.5~2范围内时,预测结果相对误差几乎均在-16%以内,仍具有较好可靠性。该公式可用于预测常压高温下NH_(3)、H_(2)、CO、CH_(4)、C_(2)H_(4)、C_(2)H_(2)气体在空气中的爆炸下限。

Obtaining the lower explosion limit of combustible gas under specific operating conditions is the basis for conducting explosion risk assessment and explosion prevention.Existing research has basically understood the influence of temperature on the lower explosion limit of gas,but there is still a lack of engineering methods that can be easily used to predict the lower explosion limit of different types of gas at high temperatures.Based on the lower explosion limit data of different types of gas at different temperatures and atmospheric pressure given in the literatures,a relationship for predicting the lower explosion limit LELT at temperature T from the value LELTo at reference temperature T_(0) was proposed as follows:(LEL_(T)/LEL_(T0))=1.3-0.3(T/T_(0)).The applicable ranges were 1≤T/T_(0)≤2 and T≤723K.The predicted values were compared with the experimental ones in the literature.It was found that the predicted results were lower than the experimental results and tended to be safe in engineering application.When T/T_(0) was within the range of 1 to 1.5,the relative errors of prediction results werelower than-6%,which had good accuracy.When T/T_(0) was within the range of 1.5 to 2,the relative errors of the prediction results were almost all within-16%,which still had good reliability.This formula can be used to predict the lower explosion limit of NH_(3),H_(2),CO,CH_(4),C_(2)H_(4),C_(2)H_(2) gases in air at atmospheric pressure and high temperature.