間歇填料塔初步設(shè)計

1、間歇填料塔初步設(shè)計Preliminary design of batch packing tower（李 強）摘 要：精細化工生產(chǎn)中，液體化合物經(jīng)常會采用精餾分離提純的辦法。且往往是負(fù)壓操作，大多設(shè)計成只有精餾段的裝置。采用變壓技術(shù)，高效分離不同揮發(fā)度的混合物。根據(jù)幾十種混合待分離體系的生產(chǎn)經(jīng)驗，對關(guān)鍵設(shè)備及參數(shù)做了總結(jié)。關(guān)鍵詞：填料塔 真空 間歇 設(shè)備 選型精細化工車間完整的間歇精餾裝置中，關(guān)鍵設(shè)備有：真空泵、精餾柱。如何設(shè)計一套適合分離體系的間歇精餾裝置，是很多工程技術(shù)人員經(jīng)常遇到的問題。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 真空度與沸點的關(guān)系。Relationship between vacuum degree and boiling point在化工熱

3、力學(xué)中，專門討論了純物質(zhì)在不同狀態(tài)下的P、V、T關(guān)系，在工程上，我們只需要知道大概的對應(yīng)趨勢關(guān)系。In chemical thermodynamics, the relationship between V, T and P in different conditions is discussed如安托因方程，描述了液體純物質(zhì)壓力與溫度的對數(shù)關(guān)系，得出溫度越高，壓力越大；反之亦然。那么在不同負(fù)壓下，純物質(zhì)的沸點（較常壓下）會降低多少？這對于我們選擇真空泵、加熱介質(zhì)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.常見真空度與沸點（補償）的關(guān)系表：真空度，Mpa-0.08-0.09-0.095-0.0998補償溫度值，305075100比如甲苯，正常壓力下的沸點是110.6，那么在-0.08 Mpa下 ，甲苯的沸點就只有70左右。對于在高溫下，一些會發(fā)生聚合、碳化、結(jié)焦、氧化等分離體系而言，采用高真空度精餾是必須的。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 真空泵對于已知分離體系的腐蝕性分析，顆粒狀況等，可以上網(wǎng)查找合適類型的真空泵。在這里強調(diào)兩點技術(shù)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 一般選擇極限真空度比操作壓力高半個數(shù)量級的真空泵。為保持真空度的穩(wěn)定，必須維持沖洗液溫度的穩(wěn)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.對于間歇精餾，除關(guān)鍵組份外，還有前餾分。這些低沸物，為了保證較高的回收率以及環(huán)保的要求，宜采用較低的真空度操作。因此全程精餾的壓力是變化的。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.在生產(chǎn)中，為實現(xiàn)精餾全程壓力的自控，一般在真空緩沖罐上安裝就地與遠傳壓力表、壓力變送器，遠傳壓力與緩沖罐上的放空閥聯(lián)鎖，內(nèi)操人員在DCS上操作鼠標(biāo)即可實現(xiàn)。若物料不能遇見空氣，則在緩沖罐上安裝氮氣管線與閥門，設(shè)計好該兩個閥門動作的條件即可。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) 抽氣量 一般根據(jù)精餾釜、塔柱、冷凝器、收集罐的體積和來選擇抽氣量。較常用的三種規(guī)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.推薦二者之間的關(guān)系如下：總體積，m³33668抽氣量，L/s150型280型350型根據(jù)近十家化工廠現(xiàn)場情況看，抽氣流速較大的前提下，冷凝效果相對差些，這時，可以將緩沖罐的物料進口設(shè)計成套管的方式，降降溫也可以獲得不錯的效果。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 加熱介質(zhì)的選擇根據(jù)操作壓力下，關(guān)鍵組份的沸點來選擇加熱介質(zhì)。一般要求加熱介質(zhì)的溫度高于關(guān)鍵組份的沸點約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.如需要某組份特別是新物質(zhì)的蒸發(fā)焓數(shù)據(jù)，可以通過加熱介質(zhì)的消耗，根據(jù)熱力學(xué)第一定律進行計算。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 精餾柱（精細化工的填料塔基本采用規(guī)整波紋填料）4.1 精餾柱的直徑 該參數(shù)決定了產(chǎn)能。直徑越大產(chǎn)量越大；操作壓力越大，產(chǎn)量越大，所以，簡單講提高產(chǎn)能，除了增大塔徑外可以采用加壓方式。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.高真空精餾系統(tǒng)，其直徑與采集流量的對應(yīng)關(guān)系如下表：塔徑，mm200300400500流量，m³/h0.050.120.120.180.

17、20.30.30.45根據(jù)采集流量可以容易決定采出管線的直徑。若組份的揮發(fā)度較大或易于沸騰，可以采用雙塔柱法。對于塔徑的計算，一般采用流體力學(xué)模型進行初步計算。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 精餾柱的高度 該參數(shù)決定了質(zhì)量。簡單講塔越高含量越高。對于直徑小于等于DN800的填料塔而言，等板高度近似于塔徑。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.為保證全塔分離效率，一般要求高徑比不大于55。負(fù)壓操作條件下的填料塔，其單位米壓降（溫降）較小，設(shè)計較好的精餾柱，其溫降區(qū)間在1/m1.5/m之間。因此，根據(jù)關(guān)鍵組分在塔頂、塔釜的沸點差，可以設(shè)計出塔柱的高度。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.比如甲苯回收精餾系統(tǒng)，甲苯在塔頂?shù)臍庖浩胶鉁囟葹?0（-0.08Mpa）,此時精餾釜內(nèi)的釜溫82，那么合理的高度在9米左右。以上數(shù)據(jù)也可以在實驗室模擬

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.理論高度的計算，一般采用間接法，利用芬斯克方

22、程，結(jié)合產(chǎn)品質(zhì)量要求，可以簡單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 回流比設(shè)計較好的精餾塔，操作回流比一般在25之間。若回流比過低，說明塔柱設(shè)計過高；若回流比過高，說明塔柱設(shè)計過低，造成操作費用過高?；S一般在回流管線與采出管線上安裝流量計的方式控

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.對于間歇精餾，一般采用變回流比的模式采出，即穩(wěn)定采出量（恒流采出模式），回流量隨著工況參數(shù)（大多情況下加熱介質(zhì)的壓力會有波動）的變化而變動。也有安裝回流比時間控制器的，該控制器安裝在采出管線上，其作用相當(dāng)于切斷閥，設(shè)計好閥門的開關(guān)時間程序。閥門打開時收集餾分，閥門關(guān)閉時全回流。此時塔頂?shù)臏囟茸兓^大

25、，但也保持一種動態(tài)的平衡，所以也能穩(wěn)定收集合格的餾分。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.回流比的計算，一般采用恩德伍德方程計算最小回流比。The calculation of reflux ratio, generally uses the Wood equation to calculate the minimum reflux ratio.五 冷凝器無論是內(nèi)回流還是外回流（或組合）冷凝器，都起到將氣體冷凝成液體，并全部或部分回流到塔內(nèi)的作用。這也是精餾塔能穩(wěn)定操作的必要條

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.較常見使用的是列管式冷凝器，物料一般走管層。對于冷凝器最重要的參數(shù)就是換熱面積，一般采用2040m²的。個人認(rèn)為為獲得良好的

29、冷凝效果，還必須保證充足的相變時間。單臺冷凝器的壓降一般在0.030.05Mpa之間，有機飽和蒸汽在冷凝器內(nèi)的流速一般在712m/s。合適的冷凝器應(yīng)滿足冷凝液的溫度低于塔頂溫度12以下，若高于12，必須考慮二級冷凝。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