CN212741185U - Continuous refining plant of ethylene glycol - Google Patents

Abstract

The utility model belongs to the technical field of ethylene glycol production technique and specifically relates to an ethylene glycol continuous refining device, including evaporation kettle, rectifying column, ethylene glycol condenser and collection tank, be provided with thick ethylene glycol inlet pipe on the evaporation kettle, the evaporation kettle passes through the pipe connection with the rectifying column, the top of rectifying column is connected to the ethylene glycol condenser through the pipeline, the ethylene glycol export of ethylene glycol condenser is connected to the collection tank through the pipeline, set up the back flow between the lower extreme of collection tank and the upper end of rectifying column, be connected with the vacuum pump at the top of collection tank; the bottom of the evaporation kettle is connected with a residue tank through a residue discharge pipeline, the top of the residue tank is connected to a vacuum pump through an air pipe, and a temperature control mechanism is arranged on the residue tank. The utility model provides a continuous refining plant of ethylene glycol, through the design of residue jar, can discharge the residue in the evaporation kettle at ethylene glycol refining process, realize the refined continuity of ethylene glycol, and the security is high, and product quality obtains the assurance.

Description

Continuous refining plant of ethylene glycol

Technical Field

The utility model belongs to the technical field of ethylene glycol production technique and specifically relates to a continuous refining plant of ethylene glycol.

Background

In the industrial production of polyester, glycol is a very important chemical raw material, but in the actual production process of polyester, a large amount of crude glycol is generated, and for a device with high raw material requirement, the crude glycol can be continuously used after being refined and refined by a glycol refining device. However, the conventional ethylene glycol refining device has many defects in design, and cannot completely reach the theoretical designed processing capacity (taking the crude ethylene glycol processing capacity of 8 tons/hour as an example), mainly because the crude ethylene glycol is unreasonably selected, the rectifying tower and the evaporation kettle have serious air resistance, so that the reflux ethylene glycol of the rectifying tower cannot be started at all, the rectifying purity is not high, and the actual processing capacity can only reach 3.8 tons/hour to the maximum. In addition, the traditional refining device can only operate intermittently, when the evaporation kettle discharges slag, the refining device must be stopped for treatment, the slag discharge is completed until the evaporation kettle is restarted for use, and the time is 8 hours at the fastest speed, so that the refining device is unstable in operation, high in energy consumption and high in ethylene glycol impurity, and a large amount of diethylene glycol is generated in serious cases, and the quality is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the technical deficiencies and providing a continuous refining plant of ethylene glycol, its refining process continuity of operation that realizes ethylene glycol, and can promote the refined productivity of ethylene glycol.

In order to achieve the purpose, the utility model discloses a continuous refining plant of ethylene glycol, including the evaporation cauldron, the rectifying column, ethylene glycol condenser and holding vessel, it advances the pipe to be provided with thick ethylene glycol on the evaporation cauldron, the evaporation cauldron passes through the pipe connection with the rectifying column, and the rectifying column is located the evaporation cauldron top, the top of rectifying column is through pipe connection to ethylene glycol condenser, the ethylene glycol export of ethylene glycol condenser is through pipe connection to the holding vessel, set up the back flow between the lower extreme of holding vessel and the upper end of rectifying column, be provided with the backwash pump on the back flow, be provided with pipeline on the back flow between backwash pump and rectifying column, set up the flow valve on the back flow between pipeline and rectifying column, be connected with the vacuum pump at the top of holding vessel; there is the residue jar bottom at the evaporation kettle through arranging the sediment pipe connection, is provided with the slag-off valve on arranging the sediment pipeline, is connected to the vacuum pump through the trachea at residue jar top, is provided with the air pressure regulating valve on the trachea, and the bottom of residue jar is provided with the evacuation pipe, is provided with the exhaust-off valve on the evacuation pipe, the residue jar on be provided with temperature control mechanism.

In the technical scheme, crude glycol generated by a light component removal tower or crude glycol to be refined generated at other places enters an evaporation kettle through a crude glycol inlet pipe, a liquid level meter is arranged in the evaporation kettle and is used for displaying the liquid level of the crude glycol in the evaporation kettle, the liquid level is in the range of 40-80% and basically in a stable state in the normal working process, the glycol in the evaporation kettle is evaporated and then enters a rectifying tower for filtration, then is condensed into a collecting tank through a glycol condenser, then most of the refined glycol is output and collected or used through a conveying pipeline by using a reflux pump, and a small part of the refined glycol flows back to the rectifying tower for secondary rectifying and filtering, the refining of the glycol can be realized in the process, the refluxed refined glycol is evaporated and rectified again in the rectifying tower, and the temperature inside of the distilling tower can be reduced at the same time, the temperature in the rectifying tower is within a reasonable range, and the temperature in the rectifying tower can be controlled by controlling the reflux quantity of the refined ethylene glycol. And the design of the vacuum pump at the top of the collecting tank can ensure that the insides of the evaporation kettle, the rectifying tower, the condenser, the collecting tank and the like are in a negative pressure state, thereby not only ensuring the smooth transportation of the ethylene glycol, but also reducing the boiling point of the ethylene glycol in the negative pressure state and further reducing the energy consumption. When the liquid level in the evaporation kettle continuously rises in the normal working process, the fact that the impurities, residues and the like are generated at the bottom of the evaporation kettle is proved, and the impurities, the residues and the like need to be discharged. At this moment, the air pressure regulating valve on the air pipe between the residue tank and the vacuum pump is only required to be opened, the vacuum pump makes the production negative pressure in the residue tank by vacuumizing in the residue tank, and is consistent with or close to the negative pressure value of the inside such as an evaporation kettle, the slag discharge valve is opened at this moment, then the residue at the bottom of the evaporation kettle is discharged into the residue tank through the slag discharge pipeline, and the temperature control mechanism is required to heat the inside of the residue tank before slag discharge, so that the temperature of the residue tank is kept at about 120 ℃, when the liquid level in the evaporation kettle is reduced to a normal range, the slag discharge valve can be closed by reducing 80% to 40% of the general liquid level. And then the air pressure regulating valve on the air pipe is closed, and the residue in the residue tank can be emptied and transported to other recycling factories, such as a coating factory, by opening the emptying valve. The above scheme can directly discharge the residues generated in the evaporation kettle in the refining process of the ethylene glycol without stopping the machine for waiting, thereby realizing continuous refining of the ethylene glycol and improving the refining capacity. In addition, the crude glycol inlet pipe is arranged on the evaporation kettle, so that the crude glycol is prevented from entering the evaporation kettle from the rectifying tower, the crude glycol is prevented from flowing downwards in the rectifying tower, the glycol generated by the evaporation kettle moves upwards, and accordingly, the air resistance phenomenon is generated, the crude glycol is prevented from directly contacting the filler section of the rectifying section, and the filler pollution is prevented.

An inert gas input pipe is arranged on the residue tank, and a control valve is arranged on the inert gas input pipe. Wherein the inert gas is preferably nitrogen. After the residue in the evaporation kettle is discharged into the residue tank, the residue discharge valve and the air pressure regulating valve are closed, and the interior of the residue tank is still in a negative pressure state, so that the residue flows out slowly in the residue emptying process, and the efficiency is influenced. Therefore, nitrogen is introduced into the residue tank, the air pressure in the residue tank can be increased to be balanced with the external atmospheric pressure, slag discharge is facilitated, the nitrogen concentration in the residue tank is increased after the nitrogen is introduced, residues after ethylene glycol refining can possibly generate certain combustible gas, and the safety is higher after the nitrogen concentration is increased.

The waste gas condenser is arranged on the gas pipe, the liquid discharge pipe is arranged on the waste gas condenser, the end part of the liquid discharge pipe is connected with the waste liquid collecting barrel, and the liquid discharge valve is arranged on the liquid discharge pipe. When arranging sediment to the inside vacuum pump that passes through of residue jar during to the negative pressure, can have the waste liquid of partly vaporization in the waste gas of residue jar inside, condense and collect to the waste liquid collecting vessel vaporization waste liquid through exhaust gas condenser, reduce the emission of waste liquid, waste gas, influence the environment.

And a U-shaped submerged bent structure is arranged on a liquid discharge pipe between the waste gas condenser and the liquid discharge valve. The design of U type submerged bend, need close the flowing back valve at the evacuation in-process, avoid external gas to get into, so the waste liquid line that the condensation produced temporarily exists inside the U type submerged bend, can select the size of suitable U type submerged bend according to the circumstances of reality.

The temperature control mechanism is a coil pipe arranged in the residue tank, a circulating heat medium is introduced into the coil pipe and supplied by a heat medium source, and the temperature control mechanism further comprises a controller used for controlling the temperature and the flow rate of the heat medium supplied by the heat medium source. The thermal coal medium is utilized to carry out heat preservation and temperature control on the residue tank, so that the stability of the temperature in the residue tank is ensured, and the residue is still fluid after entering the residue tank, so that the residue tank is more smoothly emptied.

The utility model provides a continuous refining plant of ethylene glycol, through the design of residue jar, can discharge the residue in the evaporation kettle at ethylene glycol refining process, realize the refined continuity of ethylene glycol, and the security is high, and product quality obtains the assurance.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

The invention is further described by the following embodiments in conjunction with the accompanying drawings.

Example 1:

as shown in fig. 1, the continuous ethylene glycol refining device described in this embodiment includes an evaporation kettle 1, a rectification tower 2, an ethylene glycol condenser 3 and a collection tank 4, a crude ethylene glycol inlet pipe 6 is disposed on the evaporation kettle 1, the evaporation kettle 1 is connected to the rectification tower 2 through a pipeline, the rectification tower 2 is located above the evaporation kettle 1, the top of the rectification tower 2 is connected to the ethylene glycol condenser 3 through a pipeline, an ethylene glycol outlet of the ethylene glycol condenser 3 is connected to the collection tank 4 through a pipeline, a return pipe 7 is disposed between the lower end of the collection tank 4 and the upper end of the rectification tower 2, a reflux pump 8 is disposed on the return pipe 7, a delivery pipeline 9 is disposed on the return pipe 7 between the reflux pump 8 and the rectification tower 2, a flow valve 22 is disposed on the return pipe 7 between the delivery pipeline 9 and the rectification tower 2, and a vacuum pump 23 is connected to the top of the collection tank 4; the bottom of the evaporation kettle 1 is connected with a residue tank 5 through a residue discharge pipeline 14, the residue discharge pipeline 14 is provided with a residue discharge valve 17, the top of the residue tank 5 is connected to a vacuum pump 23 through an air pipe 10, the air pipe 10 is provided with an air pressure regulating valve 18, the bottom of the residue tank 5 is provided with an emptying pipe 19, the emptying pipe 19 is provided with an emptying valve 20, and the residue tank 5 is provided with a temperature control mechanism 16.

An inert gas inlet pipe 15 is provided in the residue tank 5, and a control valve is provided in the inert gas inlet pipe 15. Wherein the inert gas is preferably nitrogen.

An exhaust gas condenser 11 is provided on the gas pipe 10, a drain pipe 24 is provided on the exhaust gas condenser 11, the end of the drain pipe 24 is connected to the waste liquid collecting tank 13, and a drain valve 21 is provided on the drain pipe 24.

A U-shaped submerged elbow 12 is provided on the drain pipe 24 between the exhaust gas condenser 11 and the drain valve 21.

The temperature control mechanism 16 is a coil pipe arranged in the residue tank 5, a circulating heat medium is introduced into the coil pipe, the heat medium is supplied by a heat medium source, and the temperature control mechanism further comprises a controller, and the controller is used for controlling the temperature and the flow rate of the heat medium supplied by the heat medium source.

Claims (5)

1. The utility model provides a continuous refining plant of ethylene glycol, includes evaporating kettle, rectifying column, ethylene glycol condenser and collection tank, characterized by: a crude glycol inlet pipe is arranged on the evaporation kettle, the evaporation kettle is connected with the rectifying tower through a pipeline, the rectifying tower is positioned above the evaporation kettle, the top of the rectifying tower is connected to a glycol condenser through a pipeline, a glycol outlet of the glycol condenser is connected to a collecting tank through a pipeline, a return pipe is arranged between the lower end of the collecting tank and the upper end of the rectifying tower, a reflux pump is arranged on the return pipe, a conveying pipeline is arranged on the return pipe between the reflux pump and the rectifying tower, a flow valve is arranged on the return pipe between the conveying pipeline and the rectifying tower, and a vacuum pump is connected to the top of the collecting tank; there is the residue jar bottom at the evaporation kettle through arranging the sediment pipe connection, is provided with the slag-off valve on arranging the sediment pipeline, is connected to the vacuum pump through the trachea at residue jar top, is provided with the air pressure regulating valve on the trachea, and the bottom of residue jar is provided with the evacuation pipe, is provided with the exhaust-off valve on the evacuation pipe, the residue jar on be provided with temperature control mechanism.

2. The continuous ethylene glycol refining apparatus according to claim 1, wherein: an inert gas input pipe is arranged on the residue tank, and a control valve is arranged on the inert gas input pipe.

3. The continuous ethylene glycol refining apparatus according to claim 1 or 2, wherein: the waste gas condenser is arranged on the gas pipe, the liquid discharge pipe is arranged on the waste gas condenser, the end part of the liquid discharge pipe is connected with the waste liquid collecting barrel, and the liquid discharge valve is arranged on the liquid discharge pipe.

4. The continuous ethylene glycol refining apparatus according to claim 3, wherein: and a U-shaped submerged bent structure is arranged on a liquid discharge pipe between the waste gas condenser and the liquid discharge valve.

5. The continuous ethylene glycol refining apparatus according to claim 1, wherein: the temperature control mechanism is a coil pipe arranged in the residue tank, a circulating heat medium is introduced into the coil pipe and supplied by a heat medium source, and the temperature control mechanism further comprises a controller used for controlling the temperature and the flow rate of the heat medium supplied by the heat medium source.

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