工业生产中氨水浓度如何测定.docx

工业生产中氨水浓度如何测定氨水在工业中应用非常广泛，在使用的过程中，很多场合需要对氨水的浓度进行控制，浓度的测量就非常的关键。在流程工业中，氨水浓度的测定一般有两种方式，一是取样检测，二是在线检测。取样检测的方式数据获取滞后，适用于一些间歇操作或对氨水浓度精确度要求较低的工艺过程。取样检测的方式有两种分析方法：方法一：化学滴定法该方法适用于浓度在30%以下的氨水浓度测定。氨水在水中部分氨分子与水发生解离，形成氢氧根离子和镂根离子。溶液呈碱性，化学滴定法以甲基红为指示剂，用标准硫酸溶液滴定至红色为中点，根据所用标准硫酸溶液的用量计算氨水浓度。所用的试剂：硫酸标准滴定溶液（c（l2H2SO4）=0.5mol1.或c（l2H2SO4）=1.0mol1.）甲基红指示剂lg/1.分析步骤：（1）吸取适量试样（试氨含量高低而定）注入预先盛有50ml蒸储水的25Oml锥形瓶中，加3滴甲基红指示剂，用1.0mol1.或0.5mol1.硫酸标准滴定溶液滴至出现红色为终点，记下所消耗体积。（2）测定样品密度。结果计算：NH3(%)X100%Cleri>17.03KJ1000其中：Cl一硫酸标准滴定溶液浓度，mol/1.Vl一硫酸标准滴定溶液消耗体积，mlV取样体积，mld样品密度，g/ml17.03氨的摩尔质量，g/mol注：（1）取样后应立即分析，以免样品挥发使结果偏低。（2）此样品分析操作时应在通风橱内进行。（3）滴定时应快滴慢摇方法二：密度计法此方法为快速测定法，通过测定样品的密度，查表得出氨水的浓度。密度浓度数据对比见附件。在线检测方式用于自动控制的工艺过程，能够实时反应氨水浓度，滞后小，快捷准确。减少人工劳动强度，在氨水配置、氨水使用过程中广泛应用。该方法基于密度浓度数据对比数据，通过用在线密度计实时监测氨水密度，间接控制氨水浓度。通常采用的密度测量仪表有差压式、质量式、放射式、音叉式。可参考本公众号文章密度测量仪表。氨水密度浓度数据对照表。Excel版，可在公众号后台回复“氨水”获取下载链接。NH3浓度氨水比重%g/1.0.0470.4630.9980.0940.9270.99780.1421.390.9976O.1891.854O.9974O.2362.318O.9972O.2842.785O.997O.3313.245O.9968O.3783.709O.9966O.4254.173O.9964O.4734.636O.9962O.525.1O.996O.5665.56O.99580.6126.02O.9956O.6586.48O.9954O.7046.94O.9952O.757.4O.995O.7967.86O.9948O.8428.32O.9946O.8888.781O.9944O.9349.24O.9942O.989.7O.9941.02510.140.99381.0710.580.99361.11511.020.99341.1611.450.99321.20511.90.9931.2512.340.99281.29512.780.99261.3413.220.99241.38513.660.99221.4314.10.9921.47614.560.99181.52215.020.99161.56815.480.99141.61415.940.99121.6616.40.9911.70616.840.99081.75217.320.99061.79817.980.99041.84418.240.99021.8918.70.991.93619.150.98981.98219.60.98962.02820.050.98942.07420.50.98922.1220.960.9892.16621.410.98882.21221.860.98862.25822.310.98842.30422.760.98822.3523.210.9882.39723.670.98782.44424.130.98762.49124.590.98742.53825.050.98722.58525.540.9872.65225.970.98682.67926.430.98662.72626.890.98642.77327.350.98622.8227.810.9862.86828.280.98582.91628.740.98562.96429.210.98543.01229.670.98523.0630.140.9853.10830.610.98483.12631.070.98463.20431.540.98443.252320.98423.332.470.9843.34832.930.98383.39633.40.98363.44433.860.98343.49234.330.98323.5434.790.9833.58835.260.98283.63635.720.98263.68436.180.98243.73236.650.98223.7837.110.9823.82937.580.98183.87838.060.98163.92738.530.98143.97639.010.98124.02539.480.9814.07439.950.98084.12340.430.98064.17240.90.98044.22141.380.98024.2741.850.984.31942.320.97984.36842.790.97964.41743.260.97944.46643.730.97924.51544.20.9794.56444.670.97884.61345.140.97864.66245.610.97844.71146.080.97824.7646.550.9784.80947.020.97784.85847.490.97764.90747.960.97744.95648.430.97725.00548.90.9775.05449.360.97685.10349.830.97665.15250.30.97645.20150.770.97625.2551.240.9765.351.720.97585.3552.190.97565.452.670.97545.4553.150.97525.553.630.9755.5554.10.97485.654.580.97465.6555.060.97445.755.530.97425.7556.010.9745.856.480.97385.8556.960.97365.957.430.97345.9557.910.9732658.380.9736.0558.850.97286.159.330.97266.1559.80.97246.260.280.97226.2560.750.9726.361.220.97186.3561.70.97166.462.170.97146.4562.640.97126.563.120.9716.5563.590.97086.664.060.97066.6564.530.97046.765.010.97026.7565.480.976.80165.960.96986.85266.440.96966.90366.910.96946.95467.390.96927.00567.870.9697.05668.350.96887.10768.830.96867.15869.30.96847.20969.780.96827.2670.260.9687.31170.740.96787.36271.220.96767.44371.70.96747.46472.180.96727.51572.660.9677.56673.130.96687.61773.610.96667.66874.090.96647.71974.570.96627.7775.050.9667.82275.540.96587.87476.020.96567.92676.510.96547.97876.990.96528.0377.480.9658.08277.970.96488.13478.450.96468.18678.940.96448.23879.420.96428.2979.910.9648.34380.40.96388.39680.90.96368.44981.390.96348.50281.890.96328.55582.380.9638.60881.870.96288.66183.370.96268.71483.860.96248.76784.360.96228.8284.850.9628.87285.330.96188.92485.810.96168.97686.290.96149.02886.770.96129.0887.260.9619.13287.740.96089.18488.220.96069.23688.70.96049.28889.180.9