共查询到18条相似文献,搜索用时 234 毫秒
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阐述了工业控制微机系统在千吨级对甲酚分步结晶装置中的应用,分析了对甲酚精制的加料、结晶、发汗和熔化等间歇过程的控制策略及软件设计方法。 相似文献
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芦海 《化工自动化及仪表》2011,38(1):118-120
介绍了对硝基氯苯熔融结晶分离的过程,并在结晶器温度控制方案中通过采用HONEYWELL公司的TPS系统的CL程序和RAMP/SOAK算法来满足熔融结晶的工艺控制要求,提高了结晶工序的控制性能. 相似文献
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Sun Hyung Kim Myoung Do Seo Moon Seon Tak Woo Sik Kim Dae Ryuk Yang Jeong Won Kang 《Korean Journal of Chemical Engineering》2013,30(11):1997-2000
A melt crystallization process is proposed to produce high-purity n-vinyl-2-pyrrolidinone (NVP). To produce high purity products, operation strategy plays key role in the melt crystallizer. We investigated the cooling strategy and optimal sweating time using a batch-type melt crystallizer. A slow cooling followed by a slow heating was found to be an effective temperature profile to produce high purity of NVP. The optimal sweating time was found to be about 20 minutes. For industrial application, a cascade melt crystallizer which consists of four stages was constructed and the proposed crystallization/sweating scheme was applied. Using the new melt crystallizer, NVP more than 99.99% purity can be produced in semi-continuous mode. 相似文献
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对于应用于食品和医药等领域的N-乙烯基吡咯烷酮聚合物,要求N-乙烯基吡咯烷酮单体的纯度高于99.9%,但精馏法往往达不到要求。为了解决这个问题,本文采用结晶法对纯度为99.5%的工业级N-乙烯基吡咯烷酮进行提纯以制备纯度高于99.9%的医药级产品。考察了晶种添加量、晶种添加温度、降温速率、结晶终温、养晶时间、升温速率、发汗终温和发汗时间对最终产品的收率和纯度的影响,并确定了较为适宜的工艺条件:晶种添加量为原料质量的0.1%,晶种添加温度为11℃,降温速率为6℃/h,结晶终温为6℃,养晶时间为20min,升温速率为6~8℃/h,发汗终温为12℃,发汗时间为30min。在这些条件下通过单级结晶就可以将纯度为99.5%的N-乙烯基吡咯烷酮原料提纯至99.95%以上,收率大于74.5%。该方法相对其他分离方法具有较为明显的优势。 相似文献
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具有静态混合单元的气泡分步结晶过程研究 总被引:4,自引:0,他引:4
在气泡分步结晶工艺基础上 ,开发了静态混合气泡结晶技术来提纯均四甲苯。实验表明 ,将静态混合单元引入传统气泡结晶器后 ,拓宽了有效鼓泡气速范围 ,明显改善了结晶过程气体均布及压强均布等状况 ,强化了传热、传质过程 ,提高了晶体纯度 相似文献
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低温控温结晶法分离提纯1,8-桉叶油素的工艺 总被引:1,自引:0,他引:1
采用全结晶工艺对原料桉叶油[w(cineole)=63.24%]进行分离提纯,在无晶种添加下,降温速率4℃/h、结晶终温-30℃、发汗速率5℃/h、发汗终温-19℃时,可将原料油提纯至77.52%。添加晶种后,可有效提高操作温度,缩小结晶温度的操作范围,提高产品的纯度,在降温速率4℃/h、结晶终温-25℃、发汗速率4℃/h、发汗终温-6℃的操作条件下,将原料油提纯至89.63%。实验得到了低温控温添加晶种结晶法分离提纯1,8-桉叶油素的适宜工艺流程和操作参数,该方法相对其他分离方法具有较为明显的优势。 相似文献
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Shin'ichi Kishimoto Masayoshi Naruse 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1988,43(1):71-82
It is known that rod-like crystals of aspartame, in which several needle crystals appear to be bundled together (bundle-like crystals), have remarkably improved physical properties compared to the crystals obtained from a conventional stirred crystallizer. A crystallization process for obtaining bundle-like crystals has been developed for manufacturing practice. The conditions to obtain the bundle-like crystals are that crystallization must be carried out without stirring, with a high initial concentration of aspartame so that the amount of precipitated solid after cooling is about 10 g litre?1 or more, and with rapid cooling to produce high supersaturation. A new type of crystallizer was developed for large-scale crystallization under these conditions. The pilot plant work was carried out in a 400-litre crystallizer, and it has been demonstrated that the crystallization process is technically possible and economically successful in the large-scale manufacturing of aspartame. 相似文献
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Woranee Paengjuntuek Amornchai Arpornwichanop Paisan Kittisupakorn 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2008,139(2):344-350
Batch crystallization is one of the widely used processes for separation and purification in many chemical industries. Dynamic optimization of such a process has recently shown the improvement of final product quality in term of a crystal size distribution (CSD) by determining an optimal operating policy. However, under the presence of unknown or uncertain model parameters, the desired product quality may not be achieved when the calculated optimal control profile is implemented. In this study, a batch-to-batch optimization strategy is proposed for the estimation of uncertain kinetic parameters in the batch crystallization process, choosing the seeded batch crystallizer of potassium sulfate as a case study. The information of the CSD obtained at the end of batch run is employed in such an optimization-based estimation. The updated kinetic parameters are used to modify an optimal operating temperature policy of a crystallizer for a subsequent operation. This optimal temperature policy is then employed as new reference for a temperature controller which is based on a generic model control algorithm to control the crystallizer in a new batch run. 相似文献