天安化工年产80万吨硫磺制酸工艺优化

【作者】 马青艳；

【导师】 杨劲； 李国鹏；

【作者基本信息】 昆明理工大学 ， 化学工程（专业学位）， 2020， 硕士

【摘要】 硫酸工业在国民经济中占有极其重要的地位,在有关化学工业方面的应用尤为重要,被誉为化学工业的发动机。硫磺制酸工艺具有流程简单、投资少、公用工程和动力消耗低、环境污染小、余热回收利用、经济效益好等优点。云南天安化工有限公司一期80万吨/年硫磺制酸装置于2005年3月建成投产,工艺上采用快速熔硫、机械过滤器除去杂质、机械雾化燃烧、“3+1”两转两吸、四塔两槽浓酸吸收流程,尾吸处理SO₂,其总转化率达99.83%,吸收率达99.95%。该装置自投产以来,生产稳定,能耗低,经济效益较高。但随着装置运行时间的推移,再加硫酸具有强腐蚀性的特点,近年来逐渐出现了一系列疑难问题,通常只有降低生产负荷至才能维持运行,甚至有时就只有停车检修,严重影响装置的稳定运行,亟待进行技术改造。本论文针对80万吨/年硫磺制酸装置衍生的系列问题,系统地对该装置的转化、吸收、尾气洗涤、余热综合利用等工段进行技改优化,具体内容如下:1.对核心设备转化器进行理论核算,计算结果表明,转化器的工艺参数包括通气量、触媒装填量等都符合要求,设备设计参数即转化器直径、承重面积、许用应力也都满足要求。说明转换器能够满足现行国标要求,可以开展后续的技改工作。2.针对干吸系统干燥塔阻力升高严重影响生产负荷进行技改,将干燥塔内原来的乱堆填料更换成125Y型S型陶瓷波纹规整填料,同时将干燥塔的纤维除雾器更换成金属丝网除雾器,工程验证表明,干燥塔的阻力已降到适宜的范围内,能够保证装置的顺利运行。3.针对干燥酸温升高影响生产负荷的问题,找到主要原因是由于循环冷却水的水质影响,从而需要加强循环水质的管理,坚持每班按时按量加药,按周期对循环水质进行清洗、预膜和正常处理程序。通过水质的处理使换热效果大大提高,酸温能够降到指标以内,恢复了装置的生产能力。4.针对新增低温位热能回收装置投用后,一吸塔出口酸雾量超标的问题,摸索出一些最合适本系统的控制手段:（1）尽量提高高温吸收塔的进塔酸温和出塔酸温,同时还应提高进塔气温。（2）严格控制干燥塔出口的水分。（3）对现有的一吸塔酸循环系统进行改造,合理的控制二级吸收酸量。（4）尽量提高二级吸收酸度。5.尾气洗涤装置的优化是通过增加除沫层高度、增加一根加水管、控制好吸收塔液位三项措施来实施。经过改造后的生产实践证明,该装置尾气排放指标能够控制在国家标准范围内。6.对整个系统的热效能进行技术经济分析,通过硫磺制酸工艺优化,硫酸单位产品综合能耗从-0.199 tce/t降到了-0.217 tce/t,降低了9.0%,硫酸的单位生产成本降低了46.7419元,取得了良好的节能效益和经济效益。通过对80万吨/年硫磺制酸装置进行了系统的技术改造和工艺优化,能够使其真正发挥出大型硫磺制酸装置的优越性,并更好的符合现行产业发展的新要求。为企业节能降耗、清洁生产、可持续发展探索了一条可行之路。更多还原

【Abstract】 This paper introduces sulfuric acid industry occupies an extremely important position in the national economy,especially in the application of chemical industry,known as the engine of chemical industry.Sulfur based sulfuric acid process has the advantages of simple process,less investment,low utility and power consumption,low environmental pollution,waste heat recovery and utilization,and good economic benefits.This paper takes the 800k T/a sulphur burning sulphuric acid plant of Yunnan Tian’an Chemical Co.,Ltd.was completed and put into operation in March 2005.The process adopts the processes of rapid sulfur melting,mechanical filter removal of impurities,mechanical atomization combustion,"3+1"two conversion and two absorption,four tower and two tank concentrated acid absorption.The total conversion rate and absorption rate of SO₂ are 99.83%and 99.95%respectively.Since the unit was put into operation,the production is stable,the energy consumption is low and the economic benefit is high.However,with the running time of the plant,adding sulfuric acid has the characteristics of strong corrosion.In recent years,a series of difficult problems have emerged gradually.Usually,the production load can only be maintained until the production load is reduced,and even sometimes the unit can only be shut down for maintenance,which seriously affects the stable operation of the unit,so technical transformation is urgently needed.Aiming at a series of problems arising from the 800 kt/a sulphur burning sulphuric acid plant,this paper systematically optimizes the transformation,absorption,tail gas washing and waste heat comprehensive utilization of the unit:1.The calculation results show that the process parameters of converter,including ventilation and catalyst loading,meet the requirements,and the equipment design parameters such as converter diameter,bearing area and allowable stress also meet the requirements.It shows that the converter can meet the requirements of the current national standard and can carry out the follow-up technical transformation.2.In view of the increase of resistance of drying tower in dry absorption system which seriously affects the production load,the original random packing in the drying tower was replaced with 125Y S-shaped ceramic corrugated structured packing,and the fiber mist eliminator of drying tower was replaced with wire mesh demister.The engineering verification shows that the resistance of drying tower has been reduced to an appropriate range,which can ensure the smooth operation of the device3.In view of the problem that the increase of drying acid temperature affects the production load,it is found that the main reason is that the water quality of circulating cooling water is affected,so it is necessary to strengthen the management of circulating water quality,adhere to the principle of adding chemicals according to the amount on time in each shift,and carry out cleaning,pre filming and normal treatment procedures for the circulating water quality according to the cycle.Through the treatment of water quality,the heat exchange effect is greatly improved,the acid temperature can be reduced to the index,and the production capacity of the unit is restored.4.In view of the problem that the acid mist at the outlet of the primary absorption tower exceeds the standard after the newly added low-temperature heat recovery device is put into operation,some control measures that are most suitable for the system are explored.（1）the inlet and outlet acid temperatures of the high-temperature absorption tower should be increased as much as possible,and the inlet air temperature should also be increased.（2）Strictly control the moisture at the outlet of drying tower.（3）The acid circulation system of the existing primary absorption tower was reformed to control the amount of acid absorbed in the secondary stage reasonably.（4）Try to improve the secondary absorption acidity.5.The optimization of tail gas washing device is implemented by increasing the height of defoamer layer,adding a water adding pipe and controlling the liquid level of absorption tower.The production practice after transformation has proved that the tail gas emission index of the device can be controlled within the national standard range.6.The technical and economic analysis of the thermal efficiency of the whole system is carried out.Through the optimization of sulfur based sulfuric acid process,the comprehensive energy consumption per unit product of sulfuric acid is reduced from-0.199tce/t to-0.217tce/t,which is reduced by 9.0%,and the unit production cost of sulfuric acid is reduced by 46.7419yuan,which has achieved good energy-saving and economic benefits.Through the systematic technical transformation and process optimization of the 800000 T/a sulphur burning sulphuric acid plant,the advantages of large-scale sulfur-based sulphuric acid plant can be brought into full play,and better meet the new requirements of the current industrial development.A feasible way is explored for energy saving,clean production and sustainable development of enterprises.更多还原