| The acetylene gas produced by calcium carbide is inevitably present with H2S,PH3 and other impurities,which will irreversible adsorption to the HgCl2 catalyst in the subsequent synthesis process of chloroethylene,shorten its service life and affect the quality of the final product.Therefore,the purification of acetylene is very necessary.Due to the mature and easy operation conditions of the process,it has been widely used in China to purify acetylene gas by sodium hypochlorite.For the purification of acetylene gas,the manufacturer usually uses AgNO3 indicator paper to qualitatively detect the impurity content and determine whether the gas can be used as raw material to enter the next section according to the color of the paper.Based on the content of sulfur and phosphorus in acetylene gas,the reliability of the qualitative determination of AgNO3 indicator paper was studied.The experimental results show that the content of impurities in acetylene gas is still higher,even if the AgNO3 indicator paper is not coloured by the existing standard method,and the content of PH3 is around 60×10-6,H2S is around 25×10-6.Meanwhile,the concentration and total amount of sulfur and phosphorus in acetylene gas have an interactive effect on the color rendering of indicator paper,the lower the concentration,the greater the amount required.In addition,two sets of experimental devices,H2S/PH3 average absorption and instantaneous absorption,were established to investigate the removal effect of sodium hypochlorite solution on H2S and PH3,and the corresponding empirical correlations were established based on the experimental results.In the average absorption device,mainly examines the effects of the active chlorine concentration and pH value of the absorption solution on the removal rate of H2S and PH3.The experimental results show that the overall removal rate increases with the increase of active chlorine concentration,and decreases with the increase of the pH value of the sodium hypochlorite solution.The pH value has great influence on H2S and has a relatively mild effect on PH3.When the active chlorine concentration is selected at0.085%0.12%and pH value at 7.08.5,the removal rate is best under the premise of ensuring the safety.According to the experimental data,the following empirical correlations were established,where?1 and?2 are average removal rate of H2S and PH3?%???1=69.55074-51.91012 w+1766.11872w2??2=(90.37494-?24.87786?/(1+e?w-0.055?/?0.00175?)×?89.80782-0.3899pH?/88.07938?In the instantaneous absorption device,the effects of the active chlorine concentration,the pH value and the gas velocity on the removal efficiency of H2S were respectively investigated.The experimental results show that the pH value has great influence on the cleaning effect in the early stage of purifing,and the latter is mainly influenced by the active chlorine concentration in the solution.The influence of the inlet velocity on the impurity removal rate is mainly reflected in the control of the inlet velocity within a certain range.If the gas velocity is too large or too small,it is not conducive to the removal of impurities.In the end,based on the actual data collected in the industry,this paper takes empirical correlative results as an important simulation parameter,simulates the existing process of sodium hypochlorite clean acetylene gas by Aspen Plus.The simulation results are in good agreement with the industrial data,and aiming at the problems existing in the process,a waste liquid used in the preparation of sodium hypochlorite solution was established.The effect of the parameters was investigated by sensitivity analysis of the operation variables such as the the liquid flow,compounding ratio of the subsodium solution,and found the right operating range.Comparing the two processes before and after the compounding,it is concluded that the amount of waste liquid generated is reduced by half after the compounding while the purity and recovery of acetylene improved by 0.2%and 0.6%respectively.This topic studies the reliability of AgNO3 indicator paper for qualitative determination of S and P,parameter range of the cleaning by sodium hypochlorite and compounding of the process,which has a direct effect on improving the qualitative detection,improving the effect of acetylene clean and reducing waste liquid emissions.And the topic has certain guiding significance to the operation of the plant,and realizes the unification of environmental benefits and economic benefits of enterprises. |
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