间歇填料塔初步设计

1、间歇填料塔初步设计Preliminary design of batch packing tower（李 强）摘 要：精细化工生产中，液体化合物经常会采用精馏分离提纯的办法。且往往是负压操作，大多设计成只有精馏段的装置。采用变压技术，高效分离不同挥发度的混合物。根据几十种混合待分离体系的生产经验，对关键设备及参数做了总结。关键词：填料塔 真空 间歇 设备 选型精细化工车间完整的间歇精馏装置中，关键设备有：真空泵、精馏柱。如何设计一套适合分离体系的间歇精馏装置，是很多工程技术人员经常遇到的问题。The key equipment of a batch packing tower in the c

2、omplete batch distillation unit of a fine chemical plant is: vacuum pump, column. How to design a set of batch distillation device for the separation system is a problem that many engineering and technical personnel often encounter。一 真空度与沸点的关系。Relationship between vacuum degree and boiling point在化工热

3、力学中，专门讨论了纯物质在不同状态下的P、V、T关系，在工程上，我们只需要知道大概的对应趋势关系。In chemical thermodynamics, the relationship between V, T and P in different conditions is discussed如安托因方程，描述了液体纯物质压力与温度的对数关系，得出温度越高，压力越大；反之亦然。那么在不同负压下，纯物质的沸点（较常压下）会降低多少？这对于我们选择真空泵、加热介质是非常重要的。Such as Antoine equation, describing the logarithmic relati

4、onship of pure substance, temperature and pressure of liquid, it is concluded that the higher the temperature, the greater the pressure, and vice versa. So in different negative pressure, the boiling point of pure substances (under the pressure) will reduce the number of? This is very important for

5、us to choose the vacuum pump, the heating medium is very important.常见真空度与沸点（补偿）的关系表：真空度，Mpa-0.08-0.09-0.095-0.0998补偿温度值，305075100比如甲苯，正常压力下的沸点是110.6，那么在-0.08 Mpa下 ，甲苯的沸点就只有70左右。对于在高温下，一些会发生聚合、碳化、结焦、氧化等分离体系而言，采用高真空度精馏是必须的。For example, the boiling point at normal pressure is 110.6, then the boiling po

6、int of toluene is only about 70 at Mpa -0.08. At high temperatures, some polymerization and carbonization and coking, oxidation separation system, the high vacuum distillation is a must for.二 真空泵对于已知分离体系的腐蚀性分析，颗粒状况等，可以上网查找合适类型的真空泵。在这里强调两点技术要求：For the corrosion analysis of the known separation system

7、, the particles can find the suitable type of vacuum pump. Here to emphasize two technical requirements:1) 真空度 一般选择极限真空度比操作压力高半个数量级的真空泵。为保持真空度的稳定，必须维持冲洗液温度的稳定。1) the vacuum degree of vacuum is generally limited to the vacuum degree of the vacuum pump with a high degree of operation pressure. In orde

8、r to maintain the stability of the vacuum degree, we must maintain the stability of the temperature.对于间歇精馏，除关键组份外，还有前馏分。这些低沸物，为了保证较高的回收率以及环保的要求，宜采用较低的真空度操作。因此全程精馏的压力是变化的。For batch distillation, in addition to the key components, as well as the former fraction. These low boiling substances, in order

9、to ensure higher recovery and environmental protection requirements, the use of a relatively low vacuum operation. So the pressure of the whole process is changed.在生产中，为实现精馏全程压力的自控，一般在真空缓冲罐上安装就地与远传压力表、压力变送器，远传压力与缓冲罐上的放空阀联锁，内操人员在DCS上操作鼠标即可实现。若物料不能遇见空气，则在缓冲罐上安装氮气管线与阀门，设计好该两个阀门动作的条件即可。In the production

10、, for the realization of the whole distillation pressure control, generally in the vacuum buffer tank is installed on the spot and remote transmitting pressure gauges, pressure transducers, remote transmitting pressure and buffer tank vent valve interlock, operating personnel in DCS mouse operation

11、can be realized. If the material can not meet the air, the buffer tank is installed on the nitrogen pipe and valve, the design of the two valve operation conditions.2) 抽气量 一般根据精馏釜、塔柱、冷凝器、收集罐的体积和来选择抽气量。较常用的三种规格：150L/s 280 L/s 350 L/s 。2) according to the general extraction distillation reactor, tower

12、, condenser, collecting tank volume and pumping quantity to choose. More commonly used three kinds of specifications: 150L/s 280 L/s 350 L/s.推荐二者之间的关系如下：总体积，m³33668抽气量，L/s150型280型350型根据近十家化工厂现场情况看，抽气流速较大的前提下，冷凝效果相对差些，这时，可以将缓冲罐的物料进口设计成套管的方式，降降温也可以获得不错的效果。According to the nearly ten chemical plan

13、t site, pumping gas flow rate greatly under the premise, the condensation effect is relatively poor, at this moment, can buffer tank material inlet is designed into a sleeve pipe, cooling down can also obtain good results.三 加热介质的选择根据操作压力下，关键组份的沸点来选择加热介质。一般要求加热介质的温度高于关键组份的沸点约50。According to the opera

14、ting pressure, the key components of the boiling point to select the heating medium. Generally, the temperature of the heating medium is higher than that of the key component of the boiling point of about 50.如需要某组份特别是新物质的蒸发焓数据，可以通过加热介质的消耗，根据热力学第一定律进行计算。If the evaporation enthalpy data of a certain g

15、roup of components, especially the new material, can be calculated by heating medium consumption, according to the first law of thermodynamics.四 精馏柱（精细化工的填料塔基本采用规整波纹填料）4.1 精馏柱的直径 该参数决定了产能。直径越大产量越大；操作压力越大，产量越大，所以，简单讲提高产能，除了增大塔径外可以采用加压方式。4.1 the diameter of the column is determined by the diameter of

16、the column. The greater the diameter, the greater the operation pressure, the greater the output, so that the simple increase in capacity, in addition to increasing the diameter of the tower can be used to increase the pressure.高真空精馏系统，其直径与采集流量的对应关系如下表：塔径，mm200300400500流量，m³/h0.050.120.120.180.

17、20.30.30.45根据采集流量可以容易决定采出管线的直径。若组份的挥发度较大或易于沸腾，可以采用双塔柱法。对于塔径的计算，一般采用流体力学模型进行初步计算。The diameter of the pipeline can be determined easily according to the traffic flow. If the volatility of the group of large or easy to boiling, can be used by the Twin Towers column method. For the calculation of the to

18、wer diameter, the hydrodynamic model is generally used.4.2 精馏柱的高度 该参数决定了质量。简单讲塔越高含量越高。对于直径小于等于DN800的填料塔而言，等板高度近似于塔径。4.2 the height of the column determines the quality of the column. The higher the content of a simple tower. The tower diameter is less than or equal to DN800, such as plate height app

19、roximation in diameter.为保证全塔分离效率，一般要求高径比不大于55。负压操作条件下的填料塔，其单位米压降（温降）较小，设计较好的精馏柱，其温降区间在1/m1.5/m之间。因此，根据关键组分在塔顶、塔釜的沸点差，可以设计出塔柱的高度。In order to ensure the separation efficiency of the whole tower, the general requirements of high diameter ratio is not greater than 55. Under negative pressure operation,

20、the unit pressure drop (Wen Jiang) is small, and the temperature drop range is between 1 and /m at /m1.5. Therefore, according to the key components in the boiling point tower, the tower kettle, you can design a tower height.比如甲苯回收精馏系统，甲苯在塔顶的气液平衡温度为70（-0.08Mpa）,此时精馏釜内的釜温82，那么合理的高度在9米左右。以上数据也可以在实验室模拟

21、。For example, toluene recovery distillation system, toluene at the top of the gas - liquid equilibrium temperature of 70 degrees (-0.08Mpa), at this time the kettle temperature 82, then the reasonable height of about 9 meters. Above data can also be simulated in the laboratory.理论高度的计算，一般采用间接法，利用芬斯克方

22、程，结合产品质量要求，可以简单算出填料塔的大概高度。Theoretical calculation of the height. In general, the indirect method, the Fenske equation. Based on the requirement of product quality, can calculate packed tower may be highly.4.3 回流比设计较好的精馏塔，操作回流比一般在25之间。若回流比过低，说明塔柱设计过高；若回流比过高，说明塔柱设计过低，造成操作费用过高。化工厂一般在回流管线与采出管线上安装流量计的方式控

23、制回流比。The design of the distillation tower, the operation of the reflux ratio is generally between 25. If the recirculation ratio is too low, explained that the tower design is too high; if the recirculation ratio is too high, indicating that the tower design is too low, resulting in operating costs

24、are too high. The chemical plant is generally installed in the return line and the pipeline to install the flow meter way to control the reflux ratio.对于间歇精馏，一般采用变回流比的模式采出，即稳定采出量（恒流采出模式），回流量随着工况参数（大多情况下加热介质的压力会有波动）的变化而变动。也有安装回流比时间控制器的，该控制器安装在采出管线上，其作用相当于切断阀，设计好阀门的开关时间程序。阀门打开时收集馏分，阀门关闭时全回流。此时塔顶的温度变化较大

25、，但也保持一种动态的平衡，所以也能稳定收集合格的馏分。For batch distillation, the general use of variable reflux ratio of recovery, stable production output (constant current recovery mode), back flow with the parameters (most of the heating medium pressure will fluctuations) change. There is also the installation of reflux r

26、atio time controller, the controller is installed in the production line, the role is equivalent to cut off the valve, the design of the valve switch time program. When the valve opens to collect the fraction, the valve closes when the full return. At this time, the temperature of the top of the tow

27、er, but also to maintain a dynamic balance, so it can also be a stable collection of qualified fraction.回流比的计算，一般采用恩德伍德方程计算最小回流比。The calculation of reflux ratio, generally uses the Wood equation to calculate the minimum reflux ratio.五 冷凝器无论是内回流还是外回流（或组合）冷凝器，都起到将气体冷凝成液体，并全部或部分回流到塔内的作用。这也是精馏塔能稳定操作的必要条

28、件。No matter (or combination) is internal reflux or reflux condenser plays the gas is condensed into liquid, and all or part of the return to the tower. This is a necessary condition for the stable operation of the distillation tower.较常见使用的是列管式冷凝器，物料一般走管层。对于冷凝器最重要的参数就是换热面积，一般采用2040m²的。个人认为为获得良好的

29、冷凝效果，还必须保证充足的相变时间。单台冷凝器的压降一般在0.030.05Mpa之间，有机饱和蒸汽在冷凝器内的流速一般在712m/s。合适的冷凝器应满足冷凝液的温度低于塔顶温度12以下，若高于12，必须考虑二级冷凝。More common is the use of tubular condenser, material pipe layer. The most important parameter is the condenser heat transfer area, generally use the 2040m - the. Personally think that to get

30、a good result, it is necessary to ensure adequate time of phase change. The pressure drop of single condenser is generally between 0.030.05Mpa, and the flow rate of organic saturated steam in the condenser is generally 712m/s. The suitable condenser should be satisfied with the temperature below the top of the tower at 12 below the