Alkaline washing method for washing hydrogen sulfide in acetylene and determination of alkali concentration
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The hydrogen sulfide content in the acetylene gas produced by dry acetylene is 6-10 times higher than that in wet acetylene (about 0.04%-0.4%), which increases the load of cleaning. It is necessary to add a sodium hydroxide alkali washing tower before cleaning. A small test alkali concentration of 10%-15% is more effective. With the elution of hydrogen sulfide, the effective alkali concentration will decrease. Now I want to establish a method for measuring alkali concentration, hoping to make it as simple as possible. Since hydrogen sulfide exists in the alkali in the form of sodium sulfide after alkali washing, simple acid-base titration will have some problems, so everyone please pay attention. This post was last edited by limingshuguang on 2009-3-3 15:33 ]
1. You can first add PH value measurement indicators without changing the existing analysis method. Take one month as the statistical period, combine your alkali investment time, and find the relevant time correspondence. 2. Look for relevant regular indicators, and then use a pH meter. 3. You can search the national standard for the analysis of alkali sulfide and pay attention to the factors that affect acid and alkali. Personally, I think that if the indicator is not very accurate, you can use a pH meter to indicate this. This post was last posted by limingshuguang on 2009-3-3 15:34 Edit ]
The problem of acid-base determination should not be big, because the requirements for the accuracy of alkali concentration control are not high. If the concentration of the supplementary alkali solution you prepare is 15% or 20%, it only needs to be added when the alkali concentration of the tower circulating fluid is lower than 10%. The requirements for the acid-base determination operation are not high, so this analysis can be directly placed in the cleaning operation position. The laboratory only needs to test it regularly, and the usual replenishment is based on the analysis of the position.
Is it possible to calibrate with hydrochloric acid first, and then titrate with ferrous sulfate standard solution? The generated iron sulfide can exist in the acid and be black, so that the concentration of alkali solution can be accurately known.
Set up a separate desulfurization device to remove hydrogen sulfide in advance. The acetylene gas coming out of the dust removal cooling tower first enters the tube cooler to re-cool the acetylene gas with 0℃~5℃ water. The cooled acetylene gas enters the desulfurization tower and is sprayed and washed with 5~10% NaOH solution to remove hydrogen sulfide in the acetylene gas. This is the process transferred by Changzhou Guanhengtong Technology Co., Ltd.
Acid-base titration is definitely possible, and you can do phenolphthalein alkalinity and total alkalinity analysis! One uses phenolphthalein as the indicator, and the other uses methyl red (or a mixed indicator of methyl red and bromocresol green)!
After some calculation, the pH of the 0.1 mol/L sodium sulfide solution titrated to the first color change point is 10.7. Therefore, phenolphthalein is used as the indicator to titrate to colorless, and some hydrogen sulfide is generated. Therefore, the double indicator method is not very suitable. I came up with a way to first measure the total alkalinity using the acid-base titration method and the sulfide ion content using the iodometric method. Then subtract the amount of alkali equivalent to the sulfide ions from the total alkali to obtain the sodium hydroxide content. This post was last edited by xwtsq on 2009-4-4 16:53 ]