Abstract:

Wet vacuum distillation was used to separate oil and residue from one kind of rolling oil sludge. The effects of the three main factors (temperature, vacuum degree and steam flowrate) on the oil yield were studied by using the quadratic general spinning design. The results showed that the wet vacuum distillation could significantly mitigate the oil destruction and promote the oil recovery rate comparing with simple distillation. Within the range of the experimental condition, the optimal conditions were 321.4℃ in temperature, 90 kPa in vacuum degree and 1 ml·min⁻¹ in steam flowrate, at which the oil recovery rate of 57.2% could be reached. Both the excessive temperature and steam flowrate could cause the oil decomposition. If the temperature was too high, it promoted the conversion of oil from resin to aromatics and saturates because of pyrolysis. If the steam partial pressure was too high, oil transformed to aromatics from resin due to the ester-type bonds hydrolysis and the oxidation of heavy oil with co-effect of Fe₂O₃. As for the heavy organic matters, such as asphaltene, which were difficult to be removed from the distillation residuals. By raising the temperature and steam flowrate, especially raising temperature, they can be effectively decomposed and carbonized to achieve a low oil content in the residues, and thus benefitting to their recovery.

Key words: rolling oil sludge, distillation, steam, temperature, oil composition, waste treatment, recovery

摘要：

使用湿式减压蒸馏法分离轧钢含油污泥的油分和残渣。采用二次通用旋转组合设计实验，研究了温度、真空度和水蒸气流量对分离效果的影响。结果表明，相比于简单蒸馏，湿式减压蒸馏能显著减轻对油分的破坏，提高油分回收率。在实验参数范围内，当蒸馏温度为321.4℃、真空度为90 kPa、水蒸气流量为1 ml·min⁻¹时，获得最大油分回收率（57.2%）。回收油分时，过高的温度和水蒸气分压会破坏油分，前者促进油分胶质组分向芳香烃和饱和烃转化，后者则会促进脂类水解，并与Fe₂O₃作用氧化重质油组分，促进胶质组分向芳香烃转化。而对于蒸馏残渣中难以分离的沥青质等大分子有机物，可通过提高温度和水蒸气流量，特别是可以提高温度，促使其分解炭化，以获得较低的残渣含油率，便于残渣中铁金属元素的回收利用。

关键词: 轧钢含油污泥, 蒸馏, 水蒸气, 温度, 油分组成, 废物处理, 回收