CAS OpenIR
汽爆秸秆溶磷新工艺及其系统集成的研究
刘菲菲
Thesis Advisor王岚
2020-07-01
Degree Grantor中国科学院大学
Degree Name硕士
Degree Discipline生物化工
Keyword酸碱循环,汽爆秸秆,生物质炼制,腐植酸,系统集成
Abstract

磷是人类生产生活中必不可少的元素,磷素的获取必须经过磷酸盐的溶解。现行磷酸盐的溶解大都通过湿法磷酸工艺,但是湿法磷酸存在高能耗、高污染以及资源浪费等严重问题,开发一种清洁高效的溶磷新工艺迫在眉睫。酸碱再生循环理论是基于磷化工产业湿法磷酸过程提出的,并衍生出“隐性酸”和“隐性碱”的概念,以期将其用于普适的农业及工业生产过程中,最终实现清洁生产与酸碱循环。玉米秸秆蒸汽爆破后,能够产生小分子有机酸并暴露出很多的酸性基团,因此汽爆玉米秸秆是一种典型的“隐性酸”。如果能利用汽爆玉米秸秆对磷矿粉进行溶解,将对磷素的提取具有重大意义。本论文首先利用汽爆玉米秸秆溶解磷矿粉,探索了磷矿粉的溶解新工艺,并制备了秸秆腐植酸肥料,其次探究了固态发酵巨大芽孢杆菌溶解磷矿粉的新工艺,并对比分析了固态发酵与液态发酵的溶磷效果,然后将酸碱再生循环理论用于造纸碱回收,将磷酸用于木质素的提取,上清液苛化得到可以循环利用的氢氧化钠溶液。最后基于两个关键技术对生物质炼制进行了系统集成,并对其中的能量与物质流进行分析,规划了产品集成体系,主要研究结果如下: (1)玉米秸秆经蒸汽爆破后,半纤维素降解,木质素软化,细胞壁表面破裂暴露出大量活性基团,其中羟基、羧基等活性基团在高压反应釜中表现出有机酸的性质,对磷矿粉有一定的溶解效果;加入氯化钙和硫酸钙等无机盐可以加速汽爆秸秆的降解,从而增强对磷矿粉的溶解作用。研究发现,加入20%的氯化钙对溶磷效果最好,加入硫酸氢钠在180℃下反应5h时,溶磷率最大。溶磷后的秸秆形成腐植酸用于小麦盆栽实验,结果发现施加0.2%的腐植酸液小麦的株高、根长、可溶性糖含量 、叶绿素含量和相对电导率达到最大值。 (2)利用汽爆秸秆作为固态发酵的培养基培养巨大芽孢杆菌,结果发现,固态发酵第10天时,基质中有机酸含量达到最大值,其最大的溶磷率可达0.1%,是液态发酵溶磷率的5倍。对发酵后磷矿粉的表观形貌和微观尺寸表征后发现,随着发酵时间的延长,磷矿粉表面出现了凹凸不平的溶解孔洞,且磷矿粉颗粒粒径由375.43μm逐渐减小到49.73μm,说明固态发酵巨大芽孢杆菌很好地溶解了磷矿粉。 (3) 酸碱再生循环的理念用于造纸碱回收工艺,木质素的提取率可达90%,生成的循环碱液中氢氧化钠浓度可达10g/L,补加一定质量的氢氧化钠重新用于循环蒸煮,分析了碱液循环次数对生物质组分拆分的影响,发现在五次循环中,纤维的卡伯值几乎不变,但是纤维素的得率急剧下降。 (4)基于酸碱再生循环的生物质炼制系统集成中,所选的最佳技术路线节省了约42%的能耗,新的碱回收工艺节省了60%的能耗,通过物质流分析发现,可节省80%的用水量,同时形成了以造纸、木质素碳纳米管、木质素复合膜、低聚木糖和腐植酸五种产品体系,极大地提高了玉米秸秆的经济利用价值。 研究结果表明,汽爆秸秆溶解磷矿粉具有一定的可行性,种新型清洁溶磷工艺,虽然其溶磷率有限,但是溶磷后的秸秆形成了腐植酸,可以作为土壤肥料施用。固态发酵很好地发挥了节水节能的优势,利用磷酸酸化工艺不仅可以高效回收木质素,还节约了处理污水的能耗,形成了蒸煮碱液的循环。对生物质炼制过程进行系统集成,延长了产业链,提高了原料的利用率,为磷化工清洁生产和农业废弃物的利用都提供了新思路。;It is the most widely treatment method that using chemical reagents to efficiently separate the three components of lignocellulose and reaching the high value of each component biomass refinery. But the serious pollution and chemical consumption problems faced by chemical treatment have attracted a lot of attention. The acid-alkali regeneration cycle theory is based on the wet-process phosphoric acid process of the phosphorus chemical industry, and derives the concepts of "recessive acid" and "recessive alkali", with a view to applying it to universal agricultural and industrial production processes. Achieve cleaner production and acid-base cycle. In the process of refining non-wood fiber resources, non-wood contains so many silicon cells that the black liquor has high viscosity after alkali treatment, which causing difficulty in lignin recovery. Acidification is an effective method for extracting lignin from black liquor. In the process of chemical wet phosphoric acid, the use of inorganic strong acids to dissolve phosphate rock has problems of high energy consumption, high pollution, and waste of resources. It is urgent to develop a clean and efficient novel phosphorus dissolving process. This paper first studied the dissolving process of phosphate rock powder, using steam exploded corn stalk (SECS) organic acid coupled inorganic salt and solid-state fermentation of Bacillus megaterium to dissolve phosphate rock powder. Humic acid fertilizers were prepared at the same time. And then analyzing the acid-base regeneration cycle process and it’s applications of alkaline pulping. The dissolution of phosphate rock powder is a key step in the production of phosphoric acid. The process of SECS dissolving phosphate and extracting lignin with phosphoric acid forms a large phosphoric acid cycle. The supernatant after acidification with calcium hydroxide was studied. Recyclable sodium hydroxide solution and calcium phosphate precipitation were obtained. The sodium hydroxide obtained after the liquid neutralization is used for circulating cooking, forming a small cycle of the lignocellulose refining process. Finally, based on two key technologies, the process system integration of biomass refining was carried out, and the energy and material flows were analyzed. The product integration system was planned. The main results were listed as follows:(1) After the corn stalks were steam exploded, hemicellulose was degraded, lignin was softened, and the cell wall surface was ruptured to expose a large number of active groups. Among them, the active groups such as hydroxyl and carboxyl groups showed organic acid properties in the autoclave. Adding inorganic salts such as calcium chloride and calcium sulfate can accelerate the degradation of SECS, thereby dissolving the phosphate rock powder. It was found that adding 20% calcium chloride had the best effect on dissolving phosphoate. When adding sodium bisulfate at 180 ° C for 5 hours, the dissolving rate was the largest. The humic acid formed from the phosphorus-dissolved straw was used in wheat pot experiments, and the results showed that the plant height, root length, soluble sugar content, chlorophyll content, and relative electrical conductivity of wheat with 0.2% humic acid solution reached the maximum.(2) The SECS was used as a medium for solid-state fermentation to culture Bacillus megaterium. It was found that solid-state fermentation had a higher phosphorus dissolution rate and organic acid content than liquid fermentation. Characterizing the apparent morphology and microscopic size of the phosphate rock after fermentation, it was found that with the extension of the fermentation time, the regular edges of the phosphate rock gradually became round and dull, and the surface had uneven dissolving holes and the particle size of the powder gradually decreased, indicating that the solid-state fermentation of Bacillus megaterium dissolved the phosphate rock well.(3) Approximately 90% of the lignin in the black liquor was recovered during the phosphoric acidification process. The two-step process of acidification and causticizing reduced 90% of the COD in the black liquor. The concentration of sodium hydroxide in the caustic soda solution was about 10g/L. The effect of removal on lignin during the five-cycle cooking is almost unchanged, but the accumulation of salt ions in the cooking liquor has a serious effect on carbohydrate components. The degradation of carbohydrate components resulting in a sharp decrease in the yield after three cycles.(4) In the biomass refining process technology route, material recycling has realized. Compared with the traditional alkali recovery process, the system energy consumption and water consumption are greatly reduced. Through the classification and refining of raw materials, formed five product systems: paper, nanotubes, lignin composite films, xylooligosaccharides and humic acid.The research results show that the acid-alkali regeneration cycle has certain feasibility in biomass refining and phosphorus chemical industry. The use of the phosphoric acidification process not only efficiently recover the lignin in the black liquor, but also save the energy consumption of sewage treatment, forming a cycle of cooking alkaline liquor. The use of steam explosion corn stalk for the dissolution of phosphate rock powder is a new type of clean phosphorus dissolution process. Although the efficiency of phosphorus dissolving is limited, the straw after phosphorus dissolution has formed humic acid, which can be used as soil fertilizer, which provides new ideas for the clean production of phosphorus chemical industry and the utilization of agricultural waste. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/49625
Collection中国科学院过程工程研究所
Recommended Citation
GB/T 7714
刘菲菲. 汽爆秸秆溶磷新工艺及其系统集成的研究[D]. 中国科学院大学,2020.
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