Study On Purifying Polluted NHD Solvent In Industry

The performance and application of NHD solvent was outlined, the problem of NHD solvent in M-sized nitrogenous production was reviewed and analyzed. And many treatment of polluted NHD solvent was introduced. The new treatment of NHD solvent was put forward comparing with the abuse of these treatments. The new treatment was limited capacity of treatment, diseconomy, high energy consummation, high loss rate, and so on.It was important to bring forward two technological routes for purifying polluted NHD solvent in industry. The one that side line treatment——quartz sand filtration was adopted when the factory worked orderly; The other that once batch treatment——enhanced quartz sand filtration was carried out when the factory was examined and repaired.Firstly, quartz sand filtration was used for purifying the polluted NHD solvent. The experimental results showed that: in the room temperature, A range of quartz sand particle size of 0.60～0.80mm, the thickness of the bed layer was 600mm, operating pressure was 0.03MPa, filtration rate was 8.1m/h, purification treatment of the polluted NHD solution with sand as filtration material, the solid impurities removal rate was up to 83.2%, and the absorption property of NHD solvent didn't change.Secondly, the enhanced quartz sand filtration using for purifying the polluted NHD solvent that was studied. And the principle of deep filtration and the ingredients were expatiated. The experimental results showed that: in the room temperature, stirring strength and time was140r/min(1min)+60r/min(5min), adsorption time was 20min, the kind of ingredients was a, a range of ingredients particle size of 20～25μm, the amount of ingredients was 4g·L-1, operating pressure was 0.03MPa. Under optimal operation condition, the engineering application was carried out, the results showed that the solid impurities removal rate was up to 92.3%, and the absorption property of NHD solvent didn't change.The quartz sand-bed backwashing parameter was studied. The results showed that the washing effect of the enhanced quartz sand filtration sand-bed was better than the washing effect of quartz sand filtration sand-bed under the equal backwashing intensity.