某石化火炬气回收集中控制系统设计

发布时间：2018-04-25 11:56

本文选题：火炬气回收 + PID控制　；参考：《西安科技大学》2015年硕士论文

【摘要】：随着国家大力发展石化化工产业,油品炼制生产的蒸馏加压过程中不可避免的会产生火炬气,火炬气是石油化工行业工艺过程中产生的废气,其成分比较复杂主要含有碳原子、氢气及碳氢化合物,另外还包含硫氧化物、氮氧化物等酸性气体,属于易燃易爆有毒有害气体。由于其回收再利用工艺复杂但又不能直接排放而且过去的环保要求也比较低所以传统化工行业都是将其直接燃烧排放,这样既造成大量能源浪费又排放大量的温室气体污染环境;直接排放火炬气带来了严重的污染问题,大量可燃气体排放也带来了能源的浪费。为了做好火炬气的回收与利用,解决降低生产成本和治理环境污染的重要问题。中国石化集团安庆分公司为配套800万吨/年炼化一体化扩能改造项目,我参与了火炬气回收系统的建设。火炬气主要组分是氢气和烃类气体,此外还含有酸性H2S、NO2等物质,火炬气回收主要是利用压缩机的加压方式将火炬气中的可燃部分提取出来,压力的控制贯穿于整个火炬气回收过程中,传统的压力控制多采用PID经典控制来完成,在各个控制回路中以压缩机出口压力的控制最为复杂,采用了压缩机出口压力-入口流量串级控制,本文将重点分析压缩机出口压力的控制方式和实现过程。为实现火炬气回收工艺,本论文设计出基于DCS系统的控制系统,该系统包含硬件子系统和软件子系统,硬件子系统包含控制层硬件、监控层硬件和管理层硬件;软件子系统包含控制层软件和监督层软件;本工程项目在设计完成后,经过近两年十个月的施工建设,安装调试,现系统已稳定运行超过270天,回收各类火炬气.3×108Nm3,累计节省燃煤7.64万吨,且各项参数指标均达到设计的要求,取得了经济效益和环保效益的双丰收。
[Abstract]:With the development of petrochemical industry in China, flare gas will inevitably be produced in the process of distillation and pressurization of oil refining production. Torch gas is a waste gas produced in the process of petrochemical industry, and its composition is complex and mainly contains carbon atoms. Hydrogen and hydrocarbons, also containing sulfur oxides, nitrogen oxides and other acid gases, belong to flammable, explosive, toxic and harmful gases. Because the recycling process is complex, but it cannot be discharged directly, and the environmental protection requirements in the past are relatively low, the traditional chemical industry has been burning it directly. This not only causes a large amount of energy waste but also emissions a large amount of greenhouse gases to pollute the environment; the direct discharge of flare gas brings serious pollution problems, a large amount of flammable gas emissions also bring energy waste. In order to recover and utilize torch gas, the important problems of reducing production cost and controlling environmental pollution are solved. Anqing Branch of Sinopec Group participated in the construction of Torch Gas recovery system for the purpose of supporting 8 million t / a integrated capacity expansion project. The main components of the torch gas are hydrogen and hydrocarbon gases. In addition, it contains substances such as acid H _ 2S _ (no _ 2), and the recovery of the torch gas is mainly to extract the combustible part of the torch gas by using the pressurized method of the compressor. The control of pressure runs through the whole process of torch gas recovery. The traditional pressure control is accomplished by PID classical control. In each control loop, the control of compressor outlet pressure is the most complex. The compressor outlet pressure-inlet flow cascade control is adopted. The control mode and realization process of compressor outlet pressure are analyzed in this paper. In order to realize the process of torch gas recovery, this paper designs a control system based on DCS system. The system includes hardware subsystem and software subsystem, hardware subsystem includes control layer hardware, monitoring layer hardware and management layer hardware. The software subsystem consists of control layer software and supervision layer software. After nearly two years and ten months of construction, installation and commissioning, the system has been running steadily for more than 270 days. The recovery of all kinds of flare gas (3. 3 脳 10 ~ 8Nm ~ (3)) saves 76400 tons of coal burning, and all parameters meet the requirements of the design, and a double harvest of economic and environmental benefits is obtained.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X742;TP273

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