关键词: 糠醛精制装置, 二次加热, 抽出液, 抽出油, 溶剂含量, 汽提塔压力, 汽提蒸汽比例

Abstract:

Due to the limitation by the coking temperature of furfural, the bottom temperature of the stripping tower of the furfural refining unit is difficult to further increase after the extract oil recovery system undergoes three-effect evaporation. When processing high aromatic hydrocarbon feedstocks, due to the high content of aromatics and good solubility of solvents and aromatics, the extract oil of the product has a high solvent content. The method of secondary heating the extract liquid can increase the bottom temperature of the extract oil stripping tower, and has a good effect on reducing the solvent content of the extract oil. Through simulation calculation, it was found that the optimal location for the extract liquid secondary heater is between the three-effect evaporation tower and the flash tower, which can reduce the solvent content of the extract oil by 83.1% compared to no secondary heating. The optimal amount of steam used in the stripping tower is 5% of the oil extract from the bottom of the tower. The temperature at the top of the stripping tower is approximately inversely proportional to the solvent content of the extract oil at the bottom of the stripping tower, and the attention should be paid to the influence of oil carried in the overhead gas. For units with low load operation or designed processing capacity, setting up an extract oil circulation process can increase the bottom temperature of the stripper, which is beneficial for reducing the solvent content at the bottom of the stripper. By setting the secondary heating and circulation process of the extract oil, optimizing the operating pressure, top temperature, and steam volume of the stripping tower, the solvent content of the extract oil can be controlled to be less than 150 μg/g, reducing the solvent consumption of the unit.

Key words: furfural refining unit, secondary heating, extract liquid, extract oil, solvent content, stripper pressure, stripping steam ratio