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神经网络辅助丙烷氨氧化催化剂设计

Neural Network Aided Design of Catalyst for Propane Ammoxidation

【作者】 侯昭胤

【导师】 陈甘棠; 戴擎镰;

【作者基本信息】 浙江大学 , 化学工程, 1996, 博士

【摘要】 丙烯腈(Acrylonitrile简称ACN)是重要的有机合成单体,现工业上大都采用Sohio工艺由丙烯氨氧化反应制备,但随着生产规模的不断扩大和原料丙烯的紧缺,丙烷氨氧化制丙烯腈的研究引起了国内外研究者的普遍关注。近几年来,国外研究者已申请了百余篇有关丙烷氨氧化制丙烯腈的催化剂专利,主要涉及到V-P-Ox系催化剂、Ga-Sb-Ox系催化剂、VSb(W,Sn)Ox系催化剂、Bi-Mo系催化剂以及双功能催化剂,但是用于改性的组分几乎包括了除惰性气体以外的其他所有元素;其中最引人注目的是V-Sb(W,Sn)Ox系催化剂;机理的研究表明丙烯腈主要通过中间体丙烯生成,该反应的控制步骤是丙烷在催化剂表面上的脱氢过程;催化剂表面上的活性相是VSbO4和α-Sb2O4。综观所有的专利文献,丙烯腈的收率普遍偏低,目前最好的催化剂收率只有40%,尚没有一种具有工业价值的催化剂问世;该工艺开发的关键是高效催化剂的研制。 本文在综合大量文献的基础上,详细论述了催化剂设计这一前沿学科的发展历程及现状;阐述了经验的和半理论的设计方法及其可取和贡献之处;对于近几年来发展起来的计算机辅助催化剂设计,作者对其进行了充分的论述,介绍了国外刚刚研制成功的几种设计软件,并作了对比和评价。 神经网络是由大量结构和功能简单的神经元按一定的形式组织起来,用于模拟人脑的组织结构和活动规律;BP网络是人们认识最为清楚、应用最广泛的神经网络。BP模型的性能优势主要表现在模式匹配、模式分类、模式识别和模式分析等方面。从神经网络的连接模式和活动规律来看:它能客观地描述催化剂各组分之间的交互作用。在催化剂设计的初期(配方筛选过程中)有一定的辅助作用。 在设计神经网络辅助催化剂设计的学习样本时,我们在集团结构适应理论和前人研究的基础上,给出了丙烷氨氧化反应制丙烯腈的具体历程,选择了可用于丙烷氨氧化的催化剂,详细地研究了VSbWSnOx/SIAL

【Abstract】 Acrylonitrile(ACN) is an important intermediate in organic polymerization. Nearly all of the ACN produced in the world today is produced by the Sohio process. Various recent changes in the petrochemical market have created two incentives for improving current acrylonitrile(ACN) technology based on propylene ammoxidation: I) the increase in the propylene prices provides the economic driving force to evaluate alternative lower cost feedstocks and ii) required new production capacities or substitution of old plants provides the opportunity to utilize new technology. The cost of propane feedstock is about 5-6 times less than the cost of propylene and thus the development of a process based on propane as the main material appears to be the more direct evolution of propylene ammoxidation process:C3H8+NH3+O2→CH2CHCN + 4H2O (H= -151.13kcal/mol)In recent years a large number of patents have been published. These patents involve mainly about the following catalytic systems V-P-Ox, Ga-Sb-Ox, VSb(W,Sn)Ox, Bi-Mo and bifunctional catalyst. But an review of these patents indicates the most promising one is VSb(W,Sn)Ox/SIAL catalyst.The kinetics of the direct synthesis of ACN from propane on VSb(W,Sn)Ox /SIAL mixed oxides indicate that ACN forms through two parallel pathways, one directly from propane and the second, which is the prevalent path, through the intermediate fonnation of propylene. The limiting factor in the formation of ACN is the relative slowness of the step of allylic oxidation to ACN of the intermediate propylene, and the high rate of propylene oxidation to carbon oxides. The active phase in the catalyst is VSbO4 and α - Sb2O4. In literatures the best yield of ACN is about 40%. Some improvements of the catalyst is needed to increase the yield of ACN.Catalyst design largely depends on empirical and qualitative knowledges, rather than on theoretical and quantitative relationships. Therefore, artificial

  • 【网络出版投稿人】 浙江大学
  • 【网络出版年期】2006年 12期
  • 【分类号】O643.36
  • 【下载频次】401
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