煤焦油脱金属及灰分脱除技术研究

Study on Coal Tar Demetalization and De-ashing Technologies

以陕西低温煤焦油为原料,采用离心分离、电脱盐、化学反应等技术手段,开展针对煤焦油的脱金属、脱灰分等预处理技术研究,试验结果表明:离心转速3 000 r/min,电脱盐温度120℃,电场强度700 V/cm,注水量10%、混合强度为手摇200次,油溶性破乳剂THD添加量为20μg/g,脱钙剂DMM2与金属钙摩尔比为2∶1,煤焦油脱后含盐降低至3 mg/L以下,脱后含水小于1%,脱钙率超过98%,脱铁率超过90%,灰分脱除率高达92%,煤焦油中的杂质含量显著降低,可以满足后续加氢工艺的要求;当脱钙剂DMM2中添加增效剂DMA4或DMA5后,其用量减少1/2,脱钙率保持在98%以上,脱铁率、灰分脱除率均在90%以上。

Various technical methods have been adopted to study the coal tar demetalization and de - ashing technologies, including centrifugal separation, electro - static desahing, chemical reaction by using Shaanxi low - temperature coal tar as feedstock. The test results demonstrated that under the optimized conditions of 3 000 r/min centrifugal separation speed, 120 ℃ desahing temperature, 700 V/cm electric field intensity, 10% water injection, 200 times mixing intensity by hand, 20 μg/g dosage of oil soluble demulsifier THD and 2：1 molar ratio of DMM2 decalcification agent to metal, the salt content of desalted coal tar was reduced to lower than 3 mg/L, the water content was less than 1% , the decalcification rate was higher than 98% , the iron removal rate was over 90% and the ash removal rate was as high as 92%. The impurities in coal tar have been dramatically reduced, which meet the requirements of downstream hydrogenation process units. After the addition of DMA4 or DMA5 synergistic agent into decalcification agent DMM2, the dosage was reduced by 50%, the decalcification rate remains at above 98% and the removal rates of iron and ash are both greater than 90%.