Lyocell纖維生產(chǎn)中溶劑NMMO回收工藝的研究

1、論文中英文摘要作者姓名：韓增強(qiáng)論文題目：Lyocell纖維生產(chǎn)中溶劑NMMO回收工藝的研究作者簡介：韓增強(qiáng)，男，1980年02月出生，2005年09月師從于內(nèi)蒙古工業(yè) 大學(xué)武志云教授，于2008年03月獲碩士學(xué)位。中文摘要Lyocell纖維是一種首先溶解纖維素漿粕，再通過干濕法紡絲制得的再生纖維素纖維。 其采用封閉式的溶解、紡絲、溶劑回收工藝，工藝簡短，所用纖維素原料綠色環(huán)保，所用NMMO 溶劑無毒可回收，制得的 Lyocell纖維兼有合成纖維與天然纖維的雙重優(yōu)點(diǎn) ，一旦實(shí)現(xiàn)大 規(guī)模生產(chǎn)，將很有可能取代高污染性的粘膠纖維。在Lyocell纖維的生產(chǎn)中，溶劑N-甲基嗎咻-N-氧化物（簡稱NMMO

2、是一種對纖維素有 著極強(qiáng)溶解性能的叔胺氧化物，它能夠使纖維素漿粕直接溶解制得Lyocell纖維，紡絲之后的NMM漆劑和大量雜質(zhì)混在一起共存于 Lyocell纖維的紡絲廢液中。NMMOS劑由于價(jià)格上 的昂貴和在紡絲溶液制備過程中的大量使用，使得溶劑回收成了決定Lyocelll纖維生產(chǎn)成本 和Lyocell纖維工業(yè)化成敗的關(guān)鍵。其次，如果不對溶劑 NMMO行回收，那么直接排放會(huì)給 自然環(huán)境帶來或多或少的污染。基于這兩方面的原因，溶劑NMM購回收率也就成了 Lyocell纖維工業(yè)化研究的重點(diǎn)和難點(diǎn)，NMMO劑的高效回收直接決定著 Lyocell纖維的生產(chǎn)成本， 成了工業(yè)化開發(fā)Lyocell纖維的突破

3、點(diǎn)。然而，目前各國對Lyocell纖維的研究重點(diǎn)都放在了溶解紡絲上，對工業(yè)化生產(chǎn)時(shí)的主 要影響因素 NMMO?劑的回收工藝研究較少。歷史上，對 Lyocell纖維紡絲溶劑NMMO 收工藝的研究早在Lyocell纖維研制之初就開始了，但當(dāng)時(shí)的首要任務(wù)是溶解紡絲，對回收 的系統(tǒng)研究也就相對的滯后了許多。后來隨著研究的深入和工業(yè)化的開展，關(guān)于回收的一系 列專利相繼出現(xiàn)。專利 DD-A 254 199就專門研究了用陰離子交換樹脂兩步法純化NMMO；溶液的方法；1991年的EP-A-0 427 701則研究用陰離子交換樹脂一步法純化 NMMO溶液的方 法。1991年奧地利的Lenzing公司申請了專利U

4、S5,178,764 ,研究用吸附過濾方法純化回收 NMM;O1994英國Courtaulds公司 申請了專利 WO931128,7研究用粗濾，陰陽離子交換法純 化回收NMMO至此，關(guān)于NMMO1收的研究進(jìn)入了快車道，隨后 Lenzing公司先后申請了一 系列關(guān)于溶劑回收的專利，回收工藝得到不斷改進(jìn)。國內(nèi)在NMMO劑回收的研究上也開展了一些工作， 但因?yàn)橹两駴]有實(shí)現(xiàn)Lyocell纖維的 工業(yè)化生產(chǎn)，所以真正有價(jià)值的、公開發(fā)表的研究成果卻不多。到目前為止關(guān)于Lyocell纖維紡絲溶劑 NMMOJ收的專利雖然不少，但真正實(shí)現(xiàn)了工業(yè)化的只有 Lenzing公司和 Courtaulds 公司，回收率可

5、達(dá) 99.5%以上，并且自從2004年5月Lenzing公司收購Corsadi 旗下的Tencell公司之后，Lenzing公司在該行業(yè)已經(jīng)處于絕對的壟斷地位，回收專利的絕 大部分都是Lenzing公司申請的。止匕外，雖然德國、俄羅斯、韓國和中國的臺(tái)灣建成了中試 工廠，但都處于試驗(yàn)階段，很少有申請 NMM漆劑回收的專利。于是，研究與開發(fā)具有自主知識(shí)產(chǎn)權(quán)的 Lyocell纖維紡絲溶劑NMMO回收工藝具有重大 意義，它直接關(guān)系到我國Lyocell纖維工業(yè)化的成敗。本論文在Lyocell纖維的紡絲溶劑NMM回收方面進(jìn)行了一系列的研究，主要研究了 紡絲之后NMMO劑的主載體一凝固浴中NMM僻劑的高效回

6、收工藝，確定了深度絮凝、沉降、 過濾、離子交換與雙氧水氧化的回收工藝。 在成功回收的基礎(chǔ)上，對回U的NMM漆劑和BASF 的新NMMO劑在溶解紡絲性能上進(jìn)行了對比實(shí)驗(yàn)，成功檢驗(yàn)了NMMOJ收工藝的除雜效果。首先，對深度絮凝工藝做了較深入的研究。在絮凝工藝中，添加劑和絮凝劑對絮凝效果 影響都非常大，實(shí)驗(yàn)中我們對添加劑和絮凝劑進(jìn)行了篩選，篩選出有效的添加劑J和具有高效絮凝作用的陰離子聚丙烯酰胺類絮凝劑M對它們的絮凝作用進(jìn)行了實(shí)驗(yàn)。接著，分別研究了絮凝溫度、攪拌速度、添加劑和絮凝劑的添加量等因素對絮凝除雜的影響。研究結(jié)果表明，紡絲凝固浴廢液在經(jīng)過深度絮凝之后，凝固浴中的膠體和半膠體雜質(zhì)得到了有效的附

7、 聚，溶液中的非溶解性雜質(zhì)可形成高質(zhì)量的絮凝物，絮凝物量多塊大，沉降迅速，易于過濾，能有效地從 溶液里去除，除雜率達(dá)98%。絮凝不影響NMMO的含量，并且顯著提高了陰陽離子交換樹脂的交換倍率。 上述結(jié)果表明，紡絲凝固浴廢液在經(jīng)過深度絮凝之后，凝固浴中的膠體和半膠體雜質(zhì)得到了 有效的附聚，溶液中的非溶解性雜質(zhì)可形成高質(zhì)量的絮凝物，絮凝物量多塊大，沉降迅速， 易于過濾，能有效地從溶液里去除，除雜率達(dá) 98%絮凝不影響NMMOJ含量，并且顯著提高 了陰陽離子交換樹脂的交換倍率。其次，對離子交換純化工藝進(jìn)行了研究。先是對陰陽離子交換樹脂進(jìn)行了選擇，然后對 離子交換處理溫度，交換溶液的流速和離子交換終點(diǎn)

8、等進(jìn)行了研究。研究結(jié)果表明凝固浴廢 液在經(jīng)過離子交換處理之后，溶液中的有色物質(zhì)、嗎咻、鐵離子和銅離子等溶解性雜質(zhì)都被 有效去除。陰離子交換樹脂能有效地脫去溶液的顏色，25倍樹脂體積時(shí)處理液的吸光度仍然低為0.038 (450nn),脫色率達(dá)86.4%;陽離子交換樹脂能夠有效地去除溶液中的嗎咻和鐵離 子、銅離子等陽離子性雜質(zhì)；經(jīng)陰陽離子交換樹脂交換處理的溶液，其電導(dǎo)率可以顯著降低， 低于290仙s/cm,陰陽離子交換樹脂的單周期的交換倍率可達(dá)到24倍，并且樹脂通過簡單再生后可以長期使用。最后，在NMMJ雙氧水氧化研究中，對氧化溫度，氧化時(shí)間，pH值，氧化劑的加入量等進(jìn)行了研究，確定了理想的氧化工

9、藝。研究結(jié)果顯示，隨著氧化溫度的升高NMMJ轉(zhuǎn)化率先升高后降低，在65c時(shí)達(dá)到最高值。 低溫時(shí)氧化率隨溫度的升高逐漸升高是因?yàn)榈蜏貢r(shí)HQ的活性較低，反應(yīng)速率較慢，達(dá)到反應(yīng)平衡所用時(shí)間較長所致；高溫時(shí)氧化率隨溫度的升高而降低是因?yàn)镹MMf口 HQ的反應(yīng)屬于放熱反應(yīng)，溫度升高將使反應(yīng)平衡向不利于生成NMM方向移動(dòng)，導(dǎo)致NMM購產(chǎn)率變低。在氧化時(shí)間的研究中，通過對不同HPLC線上的NMNR收峰的峰面積進(jìn)行比較，可以得 出隨著反應(yīng)時(shí)間的增加，NMM勺氧化率逐漸升高。具體操作是向含有NMM勺NMM僻液中加入一定量的雙氧水（按NM幽質(zhì)的量的1.2倍加 入），在65c下氧化5小時(shí)，氧化過程中分別取樣用高效液

10、相色譜進(jìn)行檢測，得出圖譜。其 中，曲線1是氧化2h后的HPLCf圖，曲線2是氧化4h后的HPLCif圖，曲線3是氧化前的 HPLCf圖，而氧化5小時(shí)的譜圖基本與氧化4小時(shí)的譜圖基本重合，氧化率不再提高。結(jié)果 曲線1中NMM勺氧化率為71.6%,曲線2中NMM勺氧化率則達(dá)96%,并且在這兩種條件下都 沒有N-亞硝基嗎咻生成，說明雙氧水在上述氧化條件下不會(huì)將NMM NMMR化成N-亞硝基嗎咻。因此，氧化4小時(shí)就可將NMM勺96%R化成NMMO在氧化pH值的研究中，將含有NMMf口 NMMO種物質(zhì)的水溶液，在其它氧化工藝相同的 條件下，分別在弱酸性，中性和弱堿性條件下進(jìn)行氧化試驗(yàn)，同樣氧化4小時(shí)，測

11、試NMM勺氧化率。結(jié)論是在pH值為8時(shí)的氧化率最高，這可以通過向氧化體系中加入堿液來調(diào)節(jié)系統(tǒng)的 pH值。對氧化劑的加入量的研究顯示，在氧化溫度和氧化時(shí)間保持不變的條件下，NMM勺氧化率隨著雙氧水加入量的增加而升高，到了 1.2mol比的時(shí)候，氧化率基本接近最高值，變化率 逐漸趨于零，為了節(jié)省原料，并且防止過剩的雙氧水對后面的溶解造成不利影響，氧化時(shí)HQ與NMM勺摩爾比為1.2時(shí)最好。研究結(jié)果表明，雙氧水在合適的氧化條件下可以將 NMM主要分解產(chǎn)物NMM5化，氧化 產(chǎn)物為NMM留高效液相色譜（HPLC檢測沒有其它副產(chǎn)物生成，NMM勺氧化回U率高達(dá)96% 同時(shí)證實(shí)了嗎咻在氧化過程中容易被氧化成 N

12、-亞硝基嗎咻，需要在雙氧水氧化前完全去除。用上述回收工藝回收的NMM漆劑，電導(dǎo)率很低，小于290is/cm,其水溶液無色透明， 基本沒有了胺臭味?；厥盏腘MM稀溶液隨后經(jīng)過減壓濃縮，濃溶液用于再溶解紡絲，冷凝液 做洗絲用水，再溶解紡絲性能優(yōu)良，再生絲質(zhì)量良好，與 BASF勺新NMM僻劑沒有明顯區(qū)別， NMMO劑得到了高效循環(huán)利用，對降低Lyocell纖維的工業(yè)化生產(chǎn)成本具有一定的參考價(jià)值。關(guān)鍵詞：Lyocell;溶劑回收；NMMO ;離子交換；絮凝Study on the Regeneration Process of Solvent NMMO for ProducingLyocell Fib

13、erHang ZengQiangABSTRACTLyocell fiber is a kind of regenerated cellulose fiber which is obtained through dissolving cellulose pulp and then wet spinning. It is made through closed dissolution, spinning and solvent recovery .The process is short and the material is environmental protection. The solve

14、nt called NMMO used in the process is recyclable and non-toxic. Lyocell fiber have advantagesof both synthetic and natural fiber. If it can be producted in large-scale, it will likely replace high-polluting viscose fiber.In the process of production of Lyocell fiber, NMMO is short for N-Methylmorpho

15、line-N-Oxide. It is a good solvent which has the strong ability for dissolving cellulose. Lyocell fibers are produced by NMMO. After spinning, solvent NMMO will go into the coagulating bath with more impurities. Because of the high price and the strong quantity of NMMO used in preparing spinning sol

16、ution, NMMO need purify and regenerate after spinning. The purification and regeneration of NMMO becomes a key which determines the industrialization of Lyocell fibers. Besides,if NMMO is not recycled, it will bring some pollution to environment by discharging it to nature directly. Based on the two

17、 points, the recovery rate of NMMO has become the significant part of industrial research of Lyocell fiber. The efficient recovery of NMMO directly determines the cost of Lyocell fiber production and it has become the break point of development of Lyocell fiber industry.However, nowadays many counti

18、es focus on solution spinning,instead of the recovery technology of NMMO. Historically, the researches of recovery technology of NMMO in the process of production started as early as the beginning of the development and the primary task was dissolving the spinning. The systematic study of the recove

19、ry was behind relatively. Later, with further research and development of industrialization, lots of patents on recovery of NMMO emerged. Patents DD-A 254 199 is considering about the special study of the anion exchange resin with a two-step purification of aqueous NMMO method; 1991 EP-A-0 427 701 i

20、s about one-step purification using anion exchange resin method of NMMO solution. in 1991,Austrias Lenzing company applied for a patent US 5,178,764, studying adsorption filtration method of NMMO; In 1994, company of UK Courtaulds applied for a patent WO9311287, researching coarse filtration, anion

21、and cation exchange to purify NMMO. So far, studies on the recovery of NMMO got on the fast lane, following that Lenzing company applied for a series of patents on solvent recovery and recycling technology was improved continuously.Domestically, we have explore some on NMMO dissolvent recycling rese

22、arch, but we haven achieve industrialized productions of Lyocell Fiber. It is rare to see the output of pure value which is published. So far, patents concerning about Lyocell fiber spinning dissolvent and NMMO dissolvent recycling are in a great number, only the two Lenzing and Courtaulds made it.

23、They maintain the 99.5% for recycling. Since 2004, Lenzing has merged Tencell which was a branch of Tencell,Lenzing has got absolutely monopolization. Almost all the patents are applied for by Lenzing. Besides, Deutsch Russia S.Korea and Taiwan has manufactured medium experiment factories, they seld

24、om applied for the patents of that.As a result, analyzing and exploring our own intellectual property of NMMO dissolvent recycling is significant. It relates to the success of Lyocell fiber industrialize in our nation.The process of the purification and regeneration of NMMO for producing Lyocell fib

25、ers were studied in this thesis. It majored in the regeneration of NMMO in the coagulating bath. The processes that contained the following steps: flocculation, sedimentation, filtering, ion exchanging and oxidizing were studied. After regeneration, the dissolving and spinning qualities of NMMO rege

26、nerated and the new were studied. The qualities and effects of the regeneration process were checked successfully.First, the process of flocculation was studied in this thesis. In this step, the proper additive, the flocculant and the collecting agent had great effect on flocculation, so they were c

27、hosen first to get effective additive J and highly efficient flocculant M which is anionic polyacrylamide,and made a test about their flocculation.Then the influence of the temperature, the quantity of the additive and the flocculant on flocculation was studied.The results indicated that the impurit

28、ies in the form of colloid and semi-colloid got together easily after flocculation. The undissolved impuritis could form a kind of flocculate in high quality. The flocculate was big and subsided quickly. It was filtered easily and 98 percent of the impurities would be removed efficientily after floc

29、culation. Flocculation did not affect the quantity of NMMO, but can raise the ability of the ion-exchange resins.Second, the process of the ion-exchange was studied in this thesis. In this step, the proper ion-exchange resins were chosen first. Then the temperature, the flow speed of the solution an

30、d the end of the ion-exchange step was studied. The results indicated that the dissolved impurities such as colour, morpholine, ferric ions and cupric ions etc. could be removed efficiently after ion-exchange. Colored impurities could be removed by the anion exchange resin. The absorbance of the sol

31、ution was 0.038(450nm). The rate of decolourning was as high as 86.4%. Morpholine, ferric ions and cupric ions etc could be removed by the cation exchange resin efficiently. The electrical conductivity of the ion- exchanged solution was down to 290 仙 s/cm. The resincouble be used for long after simp

32、le regeneration.Finally, the oxidating process was studied in this thesis. The study majored in the influence of the temperature, the time, pH and the quantity of the H 2O2 on the oxidation. The results indicated that NMM could be oxidated to NMMO with no byproduct in proper condition.As the oxidati

33、on temperature rose, the conversion of NMM first increased and then decreased at 65 C ,reaching the highest value. In low temperature condition, oxidation rate gradually increased with increasing temperature dued to lower activity of H2O2, and at low temperature the reaction rate was slow, so it nee

34、ded more time to reach equilibrium. At high temperature oxidation rate decreased with increasing temperature because the reaction between NMM and H2O2 is exothermic. And high temperature made the equilibrium move towards the direction which was not conducive to generate NMMO, which led to a low prod

35、uction of NMMO.In the study of oxidation time, we can drew a conclusion that oxidation rate of NMM gradually increased as action time increased according to the comparison of different peak areas of different HPLC curves.Specific operation is to add a certain amount of hydrogen peroxide (by NMM 1.2

36、times the amount of material added) into he NMMO solution, which is containing NMM. oxidizing in 65 C for 5 hours, the oxidation process were sampled for testing high-performance liquid chromatography. Among them, the curve 1 is the oxidation of HPLC spectra after oxidizing 2h, curve 2 is the oxidat

37、ion after b4h,of the HPLC spectrum, curve 3 is the HPLC spectra before oxidation, and basically after 5 hours and after 4 hours of oxidation of the basic spectrum coincided. The oxidation rate is not increased. Obtaining from curve 1, the oxidation rate of 71.6%, curve 2 in the oxidation NMM rate re

38、aches 96%. Under these two conditions, no N-nitroso morpholine generated, indicating that oxidation of hydrogen peroxide in the above conditions can not oxidate NMMO and NMM to N-nitroso morpholine. Therefore, the oxidation of 4 hours for 96% of NMM can be oxidized to NMMO.In the study of oxidation

39、PH value, the two substances contains NMM and NMMO aqueous solution, in other oxidation process under the same conditions, respectively, in acidic, neutral and alkaline conditions. We take oxidation test, and under the same oxidation of 4 hours, testing NMM oxidation rate. Concluding that at pH 8, it appear the highest rate of oxidation, which can be added to the alkaline oxidation system to