氧化锆测氧工作原理CE-系列氧化锆探头是利用氧化锆浓差电势来测定氧含量的传感器,其核心的氧化锆管安置在一微型电炉内,位于整个探头的顶端。氧化锆管是由氧化锆材料掺以一定量的氧化钇或氧化钙经高温烧结后形成的稳定的氧化锆陶瓷烧结体。由于它的立方晶格中含有氧离子空穴,因此在高温下它是良好的氧离子导体。因其这一特性,在一定高温下,当锆管两边的氧含量不同时,它便是一个典型的氧浓差电池,在此电池中,空气是参比气,它与烟气分别位于内外电极。在实际的氧探头中,空气流经外电极,烟气流经内电极,当烟气氧含量P小于空气氧含量P0(20.6%02)时,空气中的氧分子从外电极上夺取4个电子形成2个氧离子,发生如下电极反应:O(P0)+4e—20-2氧离子在氧化锆管中迅速迁移到烟气边,在内电极上发生相反的电极反应:2O-2—O(PO)+4e-由于氧浓差导致氧离子从空气边迁移到烟气边,因而产生的电势又导致氧离子从烟气边反向迁移到空气边,当这两种迁移达到平衡后,便在两电极间产生一个与氧浓差有关的电势信号E,该电势信号符合〃能斯特〃方程:E=(RT/4F)Ln(P0/P)(1)式中R、F分别是气体常数和法拉第常数,T是锆管绝对温度(K),PO是空气氧含量(20.6%02),P是烟气含量。由(1)式可见,在一定的高温条件下(一般)600°C),—定的烟气氧含量便会有一对应的电势输出,在理想状态下,其电势值在高温区域内对应氧含量见附表在理想状态下,当被测烟气与参比气浓度一样时,其输出电势E值为0mV,但在实际应用中,锆管实际条件和现场情况均不是理想状态。故事实上的锆管是偏离此值的。实际上,一定氧含量锆管输出的电势为理论值和本底电势的和,我们称为无浓差条件下锆管输出的电势值为本底电势或称为零位电势,此值的大小又在不同温度下呈不同的值,并且随锆管使用期延长而变化。因此,如不对此情况处理,会严重影响整套测氧仪的准确和探头寿命。鉴于此,CE系列氧分析仪采取了〃双参数校正法〃,对探头本底电势作特殊处理,弥补了锆管的离散性缺陷,延长了探头的使用寿命。注:参比气为大气,在理想状况下(本底为零时),热电偶为K分度号。C450500550600650700750800850mV18.513mV20.64mV22.772mV24.902mV27.022mV29.128mV31.214mV33.277mV35.314mV0.2%0.182.9888.7194.45100.19105.93111.67117.41123.14128.880.557.9161.9165.9269.9273.9677.9381.9485.6489.951.047.1150.3753.6356.8960.1563.4166.6669.9273.181.540.3043.6246.4449.2652.0954.9157.7360.5563.372.036.3238.8341.3443.8546.3748.8851.3953.9056.412.532.8435.1137.3939.6641.9344.2046.4748.7451.013.030.0032.0834.1536.2338.3040.3842.4544.5346.603.527.6029.5131.4233.3335.2437.1539.0640.9742.884.025.5227.2929.0530.8232.5834.3536.1137.8839.644.523.6925.3326.9628.6030.2431.8833.5235.1636.805.022.0523.5725.0126.6228.1529.6731.2032.7234.255.520.5621.9823.4124.8326.2527.6729.1030.5231.946.019.2120.5421.8623.1924.5225.8527.1828.5129.846.517.9619.2020.4521.6922.9324.1725.4126.6627.907.016.0117.9719.1320.2921.4622.6223.7824.9426.117.515.7316.8217.9119.0020.0821.1722.2623.3524.448.014.7315.7516.7617.7818.8019.8220.8421.8622.888.513.7814.7415.6916.6417.6018.5519.5020.4621.419.012.8913.7814.6315.5716.4617.3518.2419.1420.039.512.0512.8813.7214.5515.3816.2217.0517.8918.7210.011.2512.0312.8113.5914.3615.1415.9216.7017.4810.510.4911.2211.9412.6713.3914.1214.8515.5716.3011.09.7710.4411.1211.7912.4713.1513.8214.5015.1711.59.079.7010.3310.9611.5912.2112.8413.4714.1012.08.418.999.5810.1610.7411.3211.9012.4913.0712.57.788.318.859.399.9310.4711.0011.5412.0813.07.167.668.168.659.159.6410.1410.6411.1313.56.587.037.497.948.408.859.319.7610.2214.06.016.436.847.267.678.098.518.929.3414.55.465.846.226.606.987.367.738.118.4915.04.945.285.625.966.306.646.997.337.6715.54.434.735.045.345.655.966.266.576.8816.03.934.204.484.755.025.295.565.846.1116...