Soapstock is a by-product of crude vegetable oil refining which contains soaps, neutral oil and different impurities removed from oil during the process. This substance is predominantly treated with mineral acid (splitting) to recover fatty acids from soaps. High treatment costs make it advisable to reduce the pollutants of this wastewater “at source”. The Response Surface Methodology was employed to optimize the splitting of the rapeseed soapstock. The experiments were conducted in an industrial plant operating on a continuous basis. The study factors included: phosphorus content in oil (X₁), flow rate of NaOH to the saponification section (X₂), saponification temperature (X₃), soapstock splitting temperature (X₄) and pH (X₅). The concentration of organic phosphorus compounds (Porg), COD and the acid number (AN) of post-refinery fatty acids were measured during the experiments. All the study factors substantially affect the AN, whereas the pH value during soapstock splitting has no material effect on Porg concentration, and soapstock splitting temperature has no material effect on COD. Phosphorus content in oil has a very large effect on all the study values, and when was reduced, the wastewater concentrations of Porg and COD dropped considerably while the AN of post-refinery fatty acids increased. For average value of X₁ = 185 mg/kg, the optimal conditions were as follows: X₂ = 3.08 kg/h, X₃ = 137 °C, X₄ = 91.5 °C and X₅ = 3.50. It is possible under such conditions to produce post-refinery fatty acids with an of 171 mg KOH/g and wastewater with Porg concentration 425 mg/dm³ and COD 7958 mg/dm³. The Response Surface Methodology is highly suitable for mathematical modelling of the rapeseed soapstock splitting process under industrial conditions.

皂料是粗植物油精炼的副产品，其中包含肥皂，中性油和在加工过程中从油中去除的各种杂质。该物质主要用无机酸处理（分解），以从肥皂中回收脂肪酸。高昂的处理成本使得减少“源头”废水的污染物成为明智之举。采用响应面方法优化油菜皂原料的分配。实验在连续运行的工业工厂中进行。研究因素包括：油中的磷含量（X ₁），到皂化段的NaOH流量（X ₂），皂化温度（X ₃），皂液分离温度（X ₄）和pH（X₅）。在实验过程中测量了有机磷化合物（Porg）的浓度，化学需氧量（COD）和精炼后脂肪酸的酸值（AN）。所有研究因素都对AN产生实质性影响，而皂液分解过程中的pH值对Porg浓度没有实质性影响，皂液分解温度对COD则没有实质性影响。石油中的磷含量对所有研究值都有非常大的影响，当降低磷含量时，Porg和COD的废水浓度将大大下降，而精炼后脂肪酸的AN则增加。对于X ₁  = 185 mg / kg的平均值，最佳条件如下：X ₂  = 3.08 kg / h，X ₃  = 137°C，X ₄  = 91.5°C和X ₅ = 3.50。在这种条件下，可能会生产出171 mg KOH / g的精炼后脂肪酸和Porg浓度425 mg / dm ³和COD 7958 mg / dm ^3的废水。响应面方法学非常适合于工业条件下油菜皂料分解过程的数学建模。