蛋氨酸皂化液冷冻除碱过程研究

对蛋氨酸皂化液的冷却结晶除碱过程进行了研究,系统考察了冷却终温、降温速率、晶种添加量等结晶参数对冷却结晶产品十水碳酸钠的纯度以及碳酸钠脱除率的影响。实验结果表明:随着冷却终温的升高,碳酸钠的脱除率逐渐降低,十水碳酸钠的纯度先增加然后几乎保持不变;随着降温速率的增大,十水碳酸钠的纯度逐渐降低,碳酸钠的脱除率变化不大;随着十水碳酸钠晶种添加量的增加,十水碳酸钠的纯度先增加后降低,碳酸钠的脱除率几乎不变。优化工艺条件:降温速率为0.05℃/min,晶种添加量为7.5%(以生成结晶产品的质量为基准),冷冻终温为-10℃。在优化工艺条件下制备的十水碳酸钠的纯度为96.41%,皂化液的碳酸钠脱除率为81.2%。

Investigation on removal process of sodium carbonate from methionine saponification solution using cooling crystallization

The cooling crystallization and alkaline removing process of methionine saponification solution was studied.The effects of crystallization parameters,such as cooling final temperature,cooling rate and seed addition amount,on the purity and removal rate of sodium carbonate from decahydrate of crystallization products were systematically investigated.Experimental results showed that the removal rate of sodium carbonate decreased gradually with the increase of the cooling terminal temperature. Meanwhile,the purity of sodium carbonate decahydrate increased firstly and then remained almost unchanged.As the cooling rate increases,the purity of sodium carbonate decahydrate decreased gradually,and the removal rate of sodium carbonate did not change much.With the increase of the number of crystal seeds of sodium carbonate decahydrate,the purity of sodium carbonate decahydrate increased first and then decreased,and the removal rate of sodium carbonate was almost unchanged.Optimization of process conditions were obtained: the cooling rate of 0.05 ℃/min,seed addition amount of 7.5%（based on the quality of the crystalline product）,the terminal temperature of frozen for-10 ℃. Under the conditions,the crystal purity of sodium carbonate decahydrate was 96.41%,and the removal rate of sodium carbonate in saponification solution was 81.2%.