A frit distillation column for separating ethanol water mixtures

The annual processing capacity is 70,000 tons.

A year is calculated as 300 days (60 days are reserved for maintenance), which is 7200 hours.

The average processing capacity is 70000t 7200h = ethanol - water) The top composition of the tower is: 92% ethanol and 8% water

The bottom of the tower is composed of: ethanol water.

Let the top of the tower yield be d and the bottom of the tower be w

d+w=9720kg

d×92%+w×

d×8%+w×

d=？w=？

Determine the reflux ratio.

Calculate the average molar mass, the amount of steam rising.

Calculate the theoretical half.

Determine the diameter and height of the tower (consider the distance of the other disc and the height and size of the downcomer, etc.), and pay attention to roundness!

Calculate the area of the heater and the overhead condenser according to the amount of rising steam (considering the heating medium, conductivity, etc.), and sometimes add a overhead product cooler, and determine the outlet temperature, the inlet and outlet temperatures of the circulating water, etc.

For others, please consult the course instructor! This must be experienced by yourself to be memorable!

Good luck with your success!

When water and alcohol are mixed, a mixture with a fixed boiling point is formed, which is called a constant boiling point, which is higher than the boiling point of alcohol and lower than the boiling point of water.

Water in ethanol cannot be removed directly by distillation.

Because direct distilled water and ethanol will become gaseous and then liquid, the purpose of separation cannot be achieved.

And to add quicklime first, add quicklime is to remove water, lime and water reaction does not react with ethanol and Ca(OH)2 needs high temperature to decompose after the reaction, distillation is no longer produced water.

Stainless steel sieve tower.

The tower looked at the Gu. Rotameter.

Platinum resistance, thermometer display instrument.

Return roton flowmeters and distillation rotameters.

Automatic control of tower kettle liquid level: automatic control system for preventing dry burning, automatic discharge;

Raw material preheater.

Feed pump, return pump.

Raw material tank, tower top product tank, tower kettle product tank: 7L, stainless steel, automatic discharge;

Pipelines and valves: pipelines are all stainless steel, steel gate valves and copper ball valves;

Overhead condenser inlet flowmeter.

Feed flow meter.

Solenoid valve diaphragm box pressure gauge.

Temperature sensor.

The design conditions are as follows:

Operating pressure: kpa (absolute pressure).

Feed Thermal Condition: Bubble Point Feed.

Reflux ratio: Customized.

Veneer pressure drop: kpa

Heating vapor pressure at the bottom of the tower: kpa (gauge pressure).

Full tower efficiency: ET=47%.

Design calculation] 1) Determination of the design scheme.

The task of this design is to separate the methanol-water mixture. For the separation of binary mixtures, a continuous distillation process should be employed. In the design, bubble point feed is used, and the raw material liquid is heated to the bubble point through a preheater and then fed into the distillation column.

The rising vapor at the top of the tower is condensed by a full condenser, and the condensate is returned to the tower under the bubble point, and the rest is cooled by the product and sent to the storage tank. The system is easy to separate, and the minimum reflux ratio is small, so the operating reflux ratio is 2 times of the minimum reflux ratio. The tower kettle is heated by indirect steam, and the products at the bottom of the tower are cooled and sent to the storage tank.

2) Mass balance of distillation columns.

1. The molar fraction of the raw material liquid and the products at the top and bottom of the tower.

Molar mass of methanol: mA = 32 kg kmol Molar mass of water: mb = 18 kg kmol

xf=xd=

xw=2, the average molar mass of the raw solution and the product at the top and bottom of the column.

mf= kg/kmol

md= kg/kmol

mw= kg/kmol

3. Material balance.

Raw material processing capacity: f=( kmol h

Total Material Balance:

Methanol Mass Balance:

Get d= kmol h w= kmol h

iii) Determination of the number of plates.

1. Finding the number of layers MT of the theoretical board.

Methanol-water is an ideal substance, and the number of theoretical plate layers can be found by the ** method.

The gas-liquid balance data of methanol-water was obtained from the manual, and the X-Y diagram (attached table) was drawn to calculate the minimum reflux ratio and the operating reflux ratio.

Who has a Taoist Baba account, borrow it...

Foreword. Gas-liquid mass transfer equipment is indispensable in unit operations such as absorption, desorption, distillation, extraction, etc., which are widely used in the chemical industry and petroleum industry. Tower equipment is one of the gas-liquid mass transfer equipment that enables gas-liquid into two phases to achieve interphase mass transfer and heat transfer through precise contact.

Tower equipment is generally divided into two categories: interstage contact type and continuous contact type. The former is represented by plate towers, and the latter is represented by packed towers, among the various tower types, the most widely used are screen towers and floating valve towers.

Screen towers were used in industrial installations at the beginning of the 19th century, but due to the lack of research on the fluid mechanics of screen plates, they were considered difficult to operate and were not widely used. Since the fifties, due to the practice of industrial production, the sieve plate tower has been fully studied, and after a large number of industrial production and hail practice, a more perfect design method has been formed. Compared with the frying tower and the blister tower, it has the following characteristics:

The production capacity is greater than that of the plate efficiency and the output is about 15%; The pressure drop can be reduced by about 30%; In addition, the structure of the sieve plate tower is simple, the metal consumption is less, and the cost of the tray can be reduced by about 40%; It is easy to install and easy to clean and maintain.

This design is the design of the atmospheric pressure binary frit plate distillation column and the selection of auxiliary cavity equipment for the water ethanol system.

Due to the tight design time and limited level, it is inevitable that there will be omissions and fallacies, and I sincerely hope that all teachers will point them out so that they can be corrected.

Because methanol is not azeotropic with water, it is not difficult to refine methanol, only need to find the relative volatility according to the vapor pressure of pure methanol and the vapor pressure of closed spring water under the conditions of process requirements (temperature and pressure), and then calculate the required theoretical number of plates according to the purity required by the required methanol, calculate the height of the tower and then calculate the tower diameter according to the tower type (plate tower or packing tower) and output (hours) used.

The working principle and process flow of the distillation column.

The distillation column is a kind of tower vapor-liquid contact device for distillation, also known as the distillation column. There are two main types: plate towers and packed towers. According to the mode of operation, it can be divided into continuous distillation column and batch distillation column.

In the two-phase contact, the volatile (low boiling point) components in the descending liquid are continuously transferred to the vapor, and the difficult volatile (high boiling point) components in the vapor are continuously transferred to the descending liquid, the closer the vapor is to the top of the tower, the higher the concentration of volatile components, and the closer the descending liquid is to the bottom of the tower, the more enriched the difficult volatile components are to achieve the purpose of component separation. The vapor rising from the top of the column enters the condenser, and a portion of the condensed liquid returns to the top of the column as a reflux liquid into the rectification column, and the rest is taken out as a distillate. Part of the liquid flowing from the bottom of the column is fed into the reboiler, and after hot evaporation, the vapor is returned to the tower, and the other part of the liquid is taken out as the residual liquid of the kettle.

Principle of Rectification The basic principle of distillation is the partial vaporization of a liquid mixture, and the characteristics of the different volatility of each component (relative volatility, ) are used to achieve the purpose of separation. Distillation can be divided into simple distillation, flash distillation, rectification and special distillation according to its operation method.