兰州交通大学毕业设计（论文）

Abstract

Lactic acid is one of the three organic acids which widely used in the world, this design uses simultaneous saccharification and fermentation to produce lactic acid. Simultaneous saccharification and fermentation overcomes the inhibitory effect of traditional fermentation product, saving production cost, improving production efficiency. The design used the German Lactobacillus for strains and rice as the main raw materials, wheat bran auxiliary raw materials, adding CaCO3 as neutralizing agent and stabilizer of lactic acid fermentation, after fermentation, the fermentation liquid was pretreated, then a series of separation and reaction were used , finally, ion exchange treatment was adopted, we obtained lactic acid with a purity of 80%.

Keywords: production of lactic acid, fermentation technology, synchronous fermentation technology

兰州交通大学毕业设计（论文）

目 录

1 绪论 .......................................................................................................................................................... 1

1.1 乳酸的性质和应用 ........................................................................................................................ 1

1.1.1 乳酸的性质 ........................................................................................................................ 1 1.1.2 乳酸的应用 ........................................................................................................................ 1 1.1.3 乳酸的质量检测 ................................................................................................................ 1 1.2 全球市场状况及生产状况 ............................................................................................................ 2

1.2.1 全球市场状况 .................................................................................................................... 2 1.2.2 全球乳酸的生产状况 ........................................................................................................ 2 1.3 乳酸的生产方法 ............................................................................................................................ 3

1.3.1 化学合成法 ........................................................................................................................ 3 1.3.2 酶法合成 ............................................................................................................................ 3 1.3.3 发酵法生产乳酸 ................................................................................................................ 3 1.4 乳酸发酵过程的介绍 .................................................................................................................... 3

1.4.1 菌种 .................................................................................................................................... 4 1.4.2 乳酸的发酵方法 ................................................................................................................ 4 1.4.3 乳酸发酵提取分离方法 .................................................................................................... 5 1.5 我国发酵法生产乳酸的现状 ........................................................................................................ 7 1.6 我国发酵乳酸过程中存在的问题的解决方案 ............................................................................. 7 2 工艺设计及控制 ...................................................................................................................................... 8

2.1 同步糖化法生产乳酸的工艺流程................................................................................................. 8 2.2 乳酸发酵条件及控制 .................................................................................................................. 10

2.2.1 原料 .................................................................................................................................. 10 2.2.2 发酵的菌种 ...................................................................................................................... 10 2.2.3 发酵工艺控制及注意事项 .............................................................................................. 10 2.3 提取工艺及其控制 .......................................................................................................................11

2.3.1 提取工艺流程 ...................................................................................................................11 2.3.2 提取工艺条件 .................................................................................................................. 12 2.3.3 提取工艺的控制 .............................................................................................................. 12

3 工艺计算及设备选型............................................................................................................................. 15

3.1 设计工艺的条件和要求 .............................................................................................................. 15 3.2 设备计算及选型 .......................................................................................................................... 15

3.2.1 发酵罐的选型 .................................................................................................................. 15

兰州交通大学毕业设计（论文）

3.2.2 调浆罐的选型 .................................................................................................................. 16 3.2.3 种子罐的选型 .................................................................................................................. 16 3.2.4 预热罐的计算 .................................................................................................................. 16 3.2.5 压料罐计算 ...................................................................................................................... 17 3.2.6 第一次压滤 ...................................................................................................................... 17 3.2.7 第二次板框压滤 .............................................................................................................. 17 3.2.8 双效塔 .............................................................................................................................. 17 3.2.9 酸解锅 .............................................................................................................................. 18 3.2.10 第三次板框压滤 ............................................................................................................ 18 3.3 生产过程的物料衡算 .................................................................................................................. 18

3.3.1 发酵过程的物料平衡计算 .............................................................................................. 18 3.3.2 提取过程的物料衡算 ...................................................................................................... 19 3.4 生产过程的能量衡算 .................................................................................................................. 20

3.4.1 发酵过程的能量计算 ...................................................................................................... 20 3.4.2 提取过程的能量衡算 ...................................................................................................... 21

4 效益评估 ................................................................................................................................................ 22

4.1 员工工资 ...................................................................................................................................... 22 4.2 概算过程 ...................................................................................................................................... 22

4.2.1 建筑工程费 ...................................................................................................................... 22 4.2.2 设备购买费用 .................................................................................................................. 23 4.2.3 生产成本总估算 .............................................................................................................. 24 4.2.4 经济分析 .......................................................................................................................... 24

5 工业三废的处理 .................................................................................................................................... 26

5.1 有机废水的处理 .......................................................................................................................... 26 5.2 废气的处理 .................................................................................................................................. 26 5.3 废渣的处理 .................................................................................................................................. 26 6 工厂生产的安全措施............................................................................................................................. 28 结 论 .......................................................................................................................................................... 29 致 谢 ............................................................................................................................................................ 30 参考文献 ...................................................................................................................................................... 31 附录一：英文文献 附录二：英文文献翻译 附录三：设备流程图 附录四：主设备图

1 绪论

1.1 乳酸的性质和应用 1.1.1 乳酸的性质

乳酸英文名称lactic acid，学名2-羟基丙酸，分子式为C3H6O3，相对分子质量为90。呈强酸性，并具有吸湿性、旋光性，可与水、乙醇、乙醚、丙酮混溶。

葡萄糖可以在人体中分解产生水、二氧化碳和丙酮酸，同时产生少量ATP，随后丙酮酸和氢结合可以生成乳酸。当人体运动过于剧烈或着持久时，葡萄糖将会因缺氧而在身体内大量分解为乳酸，造成体内乳酸累积，使体液呈酸性，削弱细胞的正常功能。

1.1.2 乳酸的应用

乳酸在工业、食品、医药等多方面有很多用途[2]。乳酸被广泛用作防腐剂、酸味剂和还原剂。在罐头、酱类和饮料等的生产中，乳酸可以替代苯甲酸、山梨甲酸等对人体有毒副作用的防腐剂，剂，同时又可作为这些食品柔和的酸味剂；在啤酒生产过程中，利用乳酸调节pH值，不仅能促进原料糖化，而且还可以抑制杂菌的生长；乳酸乙酯是调配新香型白酒的不可缺少的香料；添加0.3％~0.5％的硬酯酰乳酸钙就可以使面包的体积增加30％～40％，同时还能防止面包老化。

乳酸在医疗方面有很多重要的应用，可以作消毒剂和载体剂。乳酸钠制成的溶液可以治疗酸中毒、高钾血症等疾病，该溶液还可解除由糖尿病或胃炎引起的中毒。乳酸酯类物质可以用做溶解药物的溶剂，增加人体对药的吸收量，降低毒副作用，该物质还能制成片剂的润滑剂。由聚乳酸制成在临床上有广泛应用的有缓释胶囊制剂、可生物降解手术缝合线、生物植入片等。

在化学工业中，乳酸是生物可降解塑料聚乳酸的主要原料，聚乳酸因其具有良好的机械性能和透气性等优点广泛被应用的同时。聚乳酸还是代替聚氯乙烯(PVC)和聚丙烯(PP)消除由“白色污染”所造成的环境危机的物质。乳酸还可以用于皮革制造行业，使皮革柔软细腻，能使纺织纤维有光泽。乳酸和乳酸钠对改善皮肤结构有很好的效果，同时乳酸酯具有溶解性好、无毒、增塑性、容易回收等优点。乳酸还可用做合成树脂涂料、胶黏剂、香料、和石油管道的清洗剂。

1.1.3 乳酸的质量检测