Conversion of waste fish meat to bio-degradable plastics poly lactic acid by sub-critcal water oxidation

以鱼骨、鱼头、鱼肉和鱼内脏为原料，研究了亚临界水水解法制备各种有机物质的工艺。确定了每种产物的最佳反应。研究了有机酸在离子交换树脂（DIAION WA30和高孔壳聚糖树脂）上的吸附平衡和传质。通过对废鱼肉、废内脏、废鱼骨的转化研究，获得了以下重要结果：(1)在473 K下反应5 min，从100吨鱼骨中提取0.64吨磷酸、0.44吨乳酸。然后，在543 K下，用亚临界水水解20分钟，得到25吨骨、1.7吨焦谷氨酸、0.8吨丙氨酸、0.8吨甘氨酸、0.5吨胱氨酸和1.8吨油。鱼头100吨，鱼骨1.5吨，焦谷氨酸0.23吨，磷酸0.07吨，油4.9吨，脂肪0.2吨。(2)油脂中含有有价值且昂贵的不饱和脂肪酸，如DHA和EPA。(3)由于最佳反应温度取决于产物类型，因此可以建立在不同反应温度下依次生产不同产物的一体化工艺。(4)用Langmuir方程很好地解释了乳酸对DIAION WA30离子交换剂的吸附等温线和壳聚糖球的吸附等温线。(5)乳酸的颗粒内扩散可以通过固相扩散和大孔扩散来解释。由于壳聚糖球的吸附速率远大于DIAION WA30，因此壳聚糖球有利于有机酸的分离。

Production of various organic substances from fish bone, fish head, fish meat and fish entrails by sub-critical water hydrolysis was studied. Optimal reaction was determined for each product. Adsorption equilibrium and mass transfer of organic acid in ion exchange resins (DIAION WA30 and highly porous chitosan resin) were also studied. The following significant results were obtained from the research on conversion of waste fish meat, entrails, and bones.(1) From 100 ton fish bone, 0.64 ton of phosphoric acid, 0.44 ton of lactic acid was extracted by 5 min reaction at 473 K.Then, 25 ton of bone, 1.7 ton of pyroglutamic acid, 0.8 ton of alanine, 0.8 ton of glycine, 0.5 ton of cystine, and 1.8 ton of oil were obtained by sub-critical water hydrolysis at 543 K for 20 min. From 100 ton of fish head, 1.5 ton of bone, 0.23 ton of pyroglutamic acid, 0.07 ton of phosphoric acid, 4.9 ton of oil, and 0.2 ton of fat were obtained.(2) Oil contained valuable and expensive unsaturated fatty acids such as DHA and EPA.(3) Since optimal reaction temperature depends on the type of products, an integrated process which produce different product successively at different reaction temperature can be established.(4) Adsorption isotherm of lactic acid for DIAION WA30 ion exchanger and that for chitosan bead were well explained by Langmuir equation.(5) Intra-particle diffusion of lactic acid was explained parallel transport by solid-phase and macropore diffusion. Since adsorption rate of the chitosan bead was much larger than that of the DIAION WA30, the chitosan bead was favorable for separation of organic acids.