RU2528997C1 - Rectifier plant - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: rectifier plant consists of two rectifier columns, each being made of cylindrical shells with contact devices. First shell top is connected with second shell bottom. Second shell bottom is connected via pump with first shell top. Proposed plant comprises boiler with inlet and outlet connected with first shell bottom. Refluxer inlet is connected with second shell top while its outlet is connected with distillate tank. Besides, it is connected via the point of reflux from refluxer, hydraulic gate and valve with first shell top. And, via gate, with second shell top, shell mid part being connected via pump with initial mix tank. Additionally, this plant incorporates distillation residue vessel with inlet connected with first shell bottom. All structural elements of rectifier column are connected by pipes.

EFFECT: decreased costs, accelerated putting in operation.

3 cl, 1 dwg

Description

The invention relates to distillation plants intended for mass transfer processes in a steam-liquid system, and can find application in chemical, petrochemical, coke, metallurgical, engineering and other industries, as well as in industrial ecology for the purification of acetic acid from impurities.

Known mass transfer distillation column for the interaction of steam with liquid, containing internal and external concentric shells, boiler, reflux condenser, collectors, pumps, pipelines (US 4681661, B01D 3/26, published. 1987).

The reasons that impede the achievement of the desired technical result include the complex strapping of the mass transfer column, including a pump for supplying steam flow from the outer shell to the inner shell, and the difficulty of installing the separation devices in the inner shell.

The closest technical solution to the claimed invention is a unit for the purification of ethanized wide fraction of light hydrocarbons from carbon dioxide (RU 2472564 C1, B01D 3/14, published. 01.20.13). The installation comprises a pipeline for supplying a liquid hydrocarbon mixture, a fractional distillation column provided with a bottom outlet for the purified liquid stream, and a top outlet for the gas stream. The fractional distillation column in the lower part is equipped with a liquid flow heating unit made in the form of a riboiler with a coolant supply, while the riboiler is connected to the lower part of the fractional distillation column. The installation has a column for the extraction of hydrocarbons from acid gas, equipped with an inlet for a gas stream, from above with an outlet of acid gases and from below with an outlet of liquid hydrocarbons, and the output of liquid hydrocarbons is connected through the installed pump to a fractional distillation column. The column for the extraction of hydrocarbons from acid gas in the upper part has a built-in refrigerator connected to a source of refrigerant.

The disadvantages of the known device include the difficulty of starting up the process in a distillation unit with a large number of contact elements.

The technical result achieved in the proposed invention is to reduce material costs and time to start the distillation column.

The specified technical result is achieved in the invention as follows.

The distillation unit contains two separately distillation columns, each of which is made in the form of a cylindrical shell with contact devices. The upper part of the first shell is connected to the lower part of the second shell, and the lower part of the second shell using a pump with the upper part of the first shell.

The installation also contains a boiler, the inlet and outlet of which is connected to the lower part of the first shell, and a reflux condenser, the inlet of which is connected to the upper part of the second shell, and the outlet is connected to the distillate tank, and also through the point of reflux from the reflux condenser using a water seal and a valve from the top part of the first shell and through the valve with the upper part of the second shell, the middle part of which is connected by means of a pump to the capacity of the initial mixture.

The unit also includes a tank of bottoms, the input of which is connected to the lower part of the first shell.

Connections of structural elements of the distillation unit are made in the form of pipelines.

In this distillation unit is used for the processing of acetic acid.

The invention is illustrated in the drawing, which schematically shows a distillation unit.

The distillation unit contains a boiler 1, a reflux condenser 2, two distillation columns made in the form of two cylindrical shells 3, 4 with contact devices 5, pipelines 6, 7, 8. Pipeline 6 connects the upper part of the first shell 3 with the lower part of the second shell 4. Pipeline 7 connects the lower part of the second shell 4 using a pump 9 for pumping liquid mixture with the upper part of the first shell 3. The pipe 8 connects the point 10 of the output of reflux from reflux condenser 2 with the upper part of the first shell 3. Rectification unit includes a tank 11 for the initial mixture, a tank 12 of bottoms, a tank 13 of distillate, pumps 14 for supplying the original mixture to the shell 4. The pipe 8 has a water seal 15 and a valve 16.

Distillation installation works as follows.

Under stationary conditions, the separation of the mixture occurs in two distillation columns - shells 3, 4. The initial liquid mixture from the tank for the initial mixture of 11 pumps 14 is fed into the middle part of the shell 4. Steam from the boiler 1 moves up along the shell 3, then through the pipe 6 enters the lower part of the shell 4 and is sent to the reflux condenser 2.

In the reflux condenser 2 steam condenses, the resulting liquid is divided into reflux and distillate. The distillate is sent to the capacity of the distillate 13. Phlegm is sent to the upper part of the shell 4, flows down, mixes with the initial mixture and pumps 9 are fed to the top of the shell 3, flows down and enters the boiler 1.

From the boiler 1, part of the liquid mixture is discharged in the form of bottoms to the tank of bottoms 12. The remaining part in the form of steam moves up along the casing 3 and is sent via pipeline 6 to the casing 4 and then to the reflux condenser 2. In this case, the valve on the pipeline 8 is closed and reflux misses the casing 3.

Thus, the "classical" distillation column is divided into two parts based on the requirements for the dimensions of the equipment.

When starting the distillation unit, the valve 16 on the pipeline 8 is opened, and part of the reflux in a 1: 1 ratio is directed through the hydraulic lock 15 into the shell 3, which is accompanied by the ingress of most of the liquid phase onto the contact devices 5 with the formation of a stable vapor-liquid layer with intensive mass transfer.

The shells 3, 4 are a cylindrical apparatus, inside of which are mounted contact devices 5, for example, in the form of sieve plates. Flowing down the shells 3, 4, the liquid interacts with the steam rising upward, which was formed during the boiling of the bottom liquid in the boiler 1. A vapor-liquid layer is formed on the contact devices 5, which is characterized by intense mass transfer. Thus, in the distillation unit, a continuous nonequilibrium process of separation of the initial mixture into a distillate with a high content of a volatile component and a still residue enriched in a hardly volatile component is carried out.

Thus, the operating time of contact devices is reduced under inefficient and unstable “sprinkling” and “seepage” modes.

As the steam load on the shells 3, 4 increases, the valve 16 is gradually closed, and the distillation unit goes into a stationary mode of operation.

Claims (3)

1. A distillation unit containing two separately distillation columns, each of which is made in the form of a cylindrical shell with contact devices, the upper part of the first shell connected to the lower part of the second shell, and the lower part of the second shell using a pump with the upper part of the first shell , a boiler, the input and output of which is connected to the lower part of the first shell, a reflux condenser, the input of which is connected to the upper part of the second shell, and the output is connected to the distillate tank, and also cut the point of reflux withdrawal from the reflux condenser using a water seal and a valve with the upper part of the first shell and through the valve with the upper part of the second shell, the middle part of which is connected by means of a pump to the capacity of the initial mixture, and the capacity of the bottom residue, the input of which is connected to the lower part of the first shell . 2. The installation according to claim 1, in which the connection of the structural elements of the distillation unit is made in the form of pipelines. 3. Installation according to claim 1, which is used for the processing of acetic acid.