| The recovery value of C12 and above heavy components in butanol and octanol residue is very low,generally used for blending fuel oil.The effective recycling of high-value-added components in these heavy components realizes the high utilization value of waste resources.This paper has studied technical conditions for recycling these heavy components generated in the the production of butanol and octanol.Proposed the pretreatment of raw materials,and thin-film evaporator coupling distillation techniques to process the heavy components of butanol and octanol residue,realized the effective utilization of heavy components in the residue of butanol and octanol.Single-factor experiments in the pretreatment process were researched through pretreatment temperature,pretreatment time and mass ratio of the alkali and raw materials.On the basic of these experiments,orthogonal experiments were designed and carried on.Then the optimized technical conditions of the pretreatment for heavy components in butanol and octanol were obtained from the data collected from optimization experiments.The parameters were as follows.The time was 60 minutes,the temperature was 80°C,and mass ratio of the alkali and raw material was 4%.After pretreatment for alkaline solution,organic acids and alkaline soluble matter were largely removed and the corrosion of materials on the separation facilities was decreased.The oil phase products obtained from the pretreatment were analyzed with gas chromatography-mass spectrometry and it was found that the main components were C12-C24--alcohols,esters and other organic compounds.Therefore,oil phase products were separated with thin-film evaporator coupling distillation techniques in order to study the single-factor effects of evaporation temperature,feed rate,and reflux ratio on the yield and content of 2-ethylhexyl 2-ethylhexanoate.Response surface experiments were designed to study the influence of thin-film evaporator coupling distillation techniques on the yield and content of 2-ethylhexyl2-ethylhexanoate in different technical conditions and interactions.Then the optimized technical conditions were obtained from the data collected from optimization experiments.The parameters were as follows.The evaporation temperature was 104.77℃,the feed rate was 14.49g/min,the reflux ratio was 2.17,.On this condition,the content of target materials was 79.56%,and the yield 85.02%.By modeling of fluid mechanics on the thin-film evaporator,the liquid film thickness of the fluid in the evaporator was calculated as 0.35mm and the residence time was 9s;on this basis,15kg/h thin-film evaporator was designed with the diameter of the evaporator as 200mm and the height 750mm.According to heat load in the evaporator and the required temperature,the heat exchange area was calculated as 0.3m2,and the evaporation area was 0.47m2.Meanwhile,the scraper was arranged inside the thin-film evaporator to make the liquid film evener and organic heat carrier（Q320）was used as the heating medium.This paper used the pretreatment and the thin-film evaporator coupling distillation separation technology is practical application value.This method can reduce environmental pollution and provide a reference for the recycling of heavy components in butanol and octanol. |
