制氢装置仪表控制系统的设计与优化

发布时间：2018-04-15 16:09

本文选题：制氢 + 测量仪表　；参考：《北京化工大学》2015年硕士论文

【摘要】：伴随着国内炼油技术水平的不断进步,对环境保护要求的提高,今后中国炼油工业加氢工艺还会有很大的发展空间,所以石油化工企业对制氢装置的建设和扩能需求量还会有大发展。烃类水蒸气转化制氢仍是未来炼厂制氢的基本工艺选择。制氢装置中的水碳比控制、变压吸附控制、转换炉燃烧是组成炼油生产工艺流程的重要环节,是轻烃蒸汽转换制氢过程中提高氢纯度、延长催化剂寿命、节约能源、资源的主要控制方案。所以,高水平的自动化控制能实现使制氢装置生产过程中工艺参数的连续性、控制的稳定可靠性。我国烃类制氢和国外综合水平还有差距,制氢综合能耗还较高。主要原因：设备质量不过关,仪表控制水平不高,操作难度大经验不足,制氢装置由于原料组成波动常常使水碳比不准、PSA吸附时间难以确定；但实际上不少安全联锁逻辑程序设计不合理导致非计划开停车较多也是制氢能耗较高。本文在深度研究分析轻烃蒸汽转化制氢工艺流程的基础上,应用现代先进的仪表控制技术,设计出制氢装置控制系统的主要回路的控制方案包括变压吸附、水碳比控制、汽包液位三冲量控制系统、转换炉温度控制和安全生产联锁保护等,并根据制氢装置运行经验对关键控制进行优化；利用DCS控制系统强大的运算控制能力,FOXBORO公司提供的先进PID控制算法达到理想的控制效果,从而达到降能减耗的目的。在检测主要的控制参数、计量水、蒸汽、风等公共能源,与紧急停车的安全联锁相关的温度、压力、流量、液位等参数时根据工况条件及工艺数据,正确的选择国内外成熟技术的自动化仪表。针对水碳比控制不稳,增加进口在线分析仪表,精准测量混合原料气组成,及准确分析碳含量,以便精确控制水碳比及燃烧的瓦斯量,达到明显的节能效果。通过优化变压吸附部分吸附时间的调整方式,提高了产品纯度及回收率。最后根据生产实际情况,结合生产需求对系统进行优化改进,利用I／A系统和TRICON系统实现了制氢装置的自动化控制与安全保护。通过对优化后运行装置的耗能数据采集、比较,装置达到最终节能降耗的控制目标。
[Abstract]:With the continuous progress of domestic refining technology and the improvement of environmental protection requirements, the hydrogenation process of China's refining industry will have a lot of room for development in the future.Therefore, petrochemical enterprises will have a great development in the construction and expansion of hydrogen production units.Hydrogen production by steam conversion of hydrocarbons is still the basic process choice in future refineries.The water / carbon ratio control, pressure swing adsorption control and conversion furnace combustion in hydrogen production unit are the important links of oil refining production process, which is to improve hydrogen purity, prolong catalyst life and save energy in hydrogen production process by light hydrocarbon steam conversion.The main control scheme of resources.Therefore, high level automatic control can realize the continuity of process parameters and the stability and reliability of the control in the production process of hydrogen production unit.There is still a gap between the comprehensive level of hydrocarbon hydrogen production in China and abroad, and the comprehensive energy consumption of hydrogen production is still relatively high.The main reasons are: the equipment quality is not up to standard, the instrument control level is not high, the operation difficulty is insufficient, the hydrogen production unit often because of the raw material composition fluctuation, it is difficult to determine the water carbon ratio not to be able to determine the PSA adsorption time;But in fact, many safety interlocking logic programs are not reasonably designed, resulting in more unplanned opening and stopping and high energy consumption for hydrogen production.On the basis of deep research and analysis of the process flow of hydrogen production by light hydrocarbon steam reforming, the main control schemes of the control system of the hydrogen production unit including pressure swing adsorption and water / carbon ratio control are designed by using the modern advanced instrument control technology.The three-impulse control system of drum liquid level, the temperature control of converter and the interlock protection of safe production are optimized according to the operation experience of hydrogen production unit.By using the powerful operation control ability of DCS control system, the advanced PID control algorithm provided by FOXBORO can achieve the ideal control effect and thus achieve the purpose of reducing energy consumption.When measuring the main control parameters, measuring water, steam, wind and other public energy sources, temperature, pressure, flow rate, liquid level and other parameters related to the safety interlocking of emergency parking, according to the operating conditions and process data,Correct selection of domestic and foreign mature technology automation instrument.Aiming at the unstable control of water-carbon ratio, the imported on-line analysis instrument is added, the composition of mixed raw gas is accurately measured, and the carbon content is accurately analyzed in order to accurately control the water-carbon ratio and the amount of burning gas, and achieve obvious energy-saving effect.The purity and recovery rate of the product were improved by optimizing the adjustment of partial adsorption time of pressure swing adsorption.Finally, according to the actual production situation, the system is optimized and improved according to the production demand, and the automatic control and safety protection of the hydrogen production unit is realized by using the I / A system and the TRICON system.By collecting and comparing the energy consumption data of the optimized operation device, the device achieves the ultimate control goal of energy saving and consumption reduction.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96;TP273

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