Hydrolysis of Urea to Produce Ammonia Dircio Francisco Xavie

发布时间：2022-11-05 02:04

　　氮氧化物（NOx）引起了巨大的环境问题,是目前世界上最大的环境污染物之一,随着对NOx法规的逐步收紧,世界各国都在积极开展减少NOx污染的研究。目前已开发利用了多种技术,其中选择性催化还原（SCR）和选择性非催化还原（SNCR）具有较高的脱硝效率。在SCR和SNCR工艺中,还原剂被注入烟气中,将NOx还原为无害氮（N2）。目前最常用的还原剂是氨（NH3）。尿素催化水解制氨在氨基脱氮过程中起着重要作用。本论文的目标有三个。首先,对尿素水解的催化剂进行筛选,其中均相催化剂表现出了良好的性能,因此本文用选择该类催化剂来进行尿素催化水解反应,然后尿素水解的转化率采用滴定法来进行分析。第二是设计了四因素,三水平Box-Behnken实验,结合响应面法对工艺条件进行优化,研究反应温度,反应时间,反应压力和催化剂用量对尿素水解制氨的影响及其交互作用。建立了尿素水解率的相关模型。第三是采用物料平衡方程,热量平衡方程,化学平衡方程及相平衡方程组成的非线性方程组来构建开口体系内尿素水解过程的热力学模型和动力学模型,并引入修正的Lewis-Randall方程和修正的Herry方程来描述水解反应器内NH3-C... 

【文章页数】：93 页

【学位级别】：硕士

【文章目录】：
abstract
摘要
CHAPTER Ⅰ INTRODUCTION
    1.1 Background
    1.2 Objective of the research
    1.3 Research significance
CHAPTER Ⅱ LITERATURE REVIEW
    2.1 Overview
    2.2 Research progress of catalytic hydrolysis of urea
    2.3 Principle of urea hydrolysis
    2.4 Introduction of solid catalyst
        2.4.1 Brief introduction of the solid acid catalyst
        2.4.2 Brief introduction of solid base catalyst
    2.5 Alumina and its precursor
        2.5.1 Alumina
        2.5.2 Precursor of alumina
    2.6 Hydrotalcite
        2.6.1 Properties of LDHs
        2.6.2 Synthesis of LDHs
    2.7 The method for production of ammonia from urea
        2.7.1 Urea pyrolysis
        2.7.2 Urea hydrolysis
    2.8 Comparison of ammonia production technology between urea hydrolysis andurea pyrolysis
    2.9 Overseas urea hydrolysis technology
        2.9.1 AOD process
        2.9.2 Urea to Ammonia (A2U) technology
        2.9.3 SafeDeNOx process
    2.10. The domestic urea hydrolysis process
    2.11 Development of urea hydrolysis process
    2.12 Research status of thermodynamic model and kinetic model of urea hydrolysis
CHAPTER Ⅲ EXPERIMENTAL SECTION,ANALYSIS AND DISCUSSION
    3.1 Reagents used in the experiment
    3.2 Experimental equipments
    3.3 Experimental set-up and process
        3.3.1 Experimental set-up
        3.3.2 Selection of catalysts and experimental process
        3.3.3 Experimental contents
    3.4 Experimental analysis of urea hydrolysis
        3.4.1 Qualitative analysis of urea hydrolysis
        3.4.2 Determination of biuret
        3.4.3 Analysis of the side reaction of urea hydrolysis
    3.5 Factors affecting the decomposition and conversion rates
        3.5.1 Effect of temperature on urea hydrolysis
        3.5.2 Effect of pressure on hydrolysis rate
        3.5.3 Effect of concentration on urea hydrolysis
        3.5.4 Effect of time on urea hydrolysis
        3.5.5 Effect of catalyst dosage on urea hydrolysis
    3.6 Optimization of reaction conditions
        3.6.1 Experimental design of response surface method
        3.6.3 Establishment of the model equation and variance test
        3.6.4 Response surface analysis
        3.6.5 Determination of the optimal condition
CHAPTER Ⅳ REACTION MODEL OF UREA HYDROLYSIS
    4.1 Reaction model of urea hydrolysis
        4.1.1 Thermodynamic Model
        4.1.2 Kinetics model
CHAPTER Ⅴ CONCLUSION
BIBLIOGRAPHY
Acknowledgement


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