阅读说明：本技术 浸没蒸发吸附回收乙二醇残液工艺 (Process for recovering residual ethylene glycol liquid by immersion, evaporation and adsorption ) 是由 韩林华 韩杨 韩飞 闫旭阳 于 2020-06-12 设计创作，主要内容包括：本发明涉及一种浸没蒸发吸附回收乙二醇残液工艺,包括：将乙二醇残液泵入浸没蒸发设备,进行加热蒸发,形成浓缩液和蒸发尾气；所述浸没蒸发设备将浓缩液输送至活性炭吸附设备,活性炭吸附设备会对浓缩液进行吸附脱色；所述活性炭吸附设备将脱色后浓缩液输送至离子交换树脂吸附设备,浓缩液进入离子交换树脂吸附设备后,离子交换树脂会对浓缩液进行吸附处理并调节浓缩液的酸度,形成目标产品。本发明所述浸没蒸发过程所用蒸发装置选用直管型浸没蒸发器,充分利用了高温锅炉烟气替代燃气作为动力源,降低了处理成本的同时,对烟气热能加以回收利用,同时本发明采用的活性炭以及离子交换树脂再生后均可重复使用,单位处理成本较精馏法下降50％以上。(The invention relates to a process for recovering ethylene glycol raffinate by immersion, evaporation and adsorption, which comprises the following steps: pumping the residual ethylene glycol liquid into an immersion evaporation device, and heating and evaporating to form a concentrated solution and an evaporation tail gas; the immersion evaporation equipment conveys the concentrated solution to activated carbon adsorption equipment, and the activated carbon adsorption equipment can adsorb and decolor the concentrated solution; the active carbon adsorption equipment conveys the decolored concentrated solution to ion exchange resin adsorption equipment, and after the concentrated solution enters the ion exchange resin adsorption equipment, the ion exchange resin can adsorb the concentrated solution and adjust the acidity of the concentrated solution to form a target product. The evaporation device used in the immersion evaporation process adopts the straight-tube immersion evaporator, the high-temperature boiler flue gas is fully utilized to replace fuel gas as a power source, the treatment cost is reduced, simultaneously, the heat energy of the flue gas is recycled, simultaneously, the activated carbon and the ion exchange resin adopted by the invention can be reused after regeneration, and the unit treatment cost is reduced by more than 50 percent compared with a rectification method.)

1. A process for recovering ethylene glycol raffinate by immersion, evaporation and adsorption is characterized by comprising the following steps:

step 1: pumping the ethylene glycol raffinate into an immersion evaporation device, heating and evaporating to form a concentrated solution and evaporation tail gas, and conveying the concentrated solution to the next device by the immersion evaporation device for subsequent treatment and outputting the evaporation tail gas for post-treatment;

step 2: the immersion evaporation equipment conveys the concentrated solution to activated carbon adsorption equipment, the activated carbon adsorption equipment can adsorb and decolor the concentrated solution, the decolored concentrated solution is conveyed to next equipment for subsequent treatment, and gas mixed in the concentrated solution is discharged for post-treatment;

and step 3: the active carbon adsorption equipment conveys the decolored concentrated solution to ion exchange resin adsorption equipment, and after the concentrated solution enters the ion exchange resin adsorption equipment, the ion exchange resin can adsorb the concentrated solution and adjust the acidity of the concentrated solution to form a target product.

2. The process for recovering the ethylene glycol raffinate through the submerged evaporation adsorption as claimed in claim 1, wherein the submerged evaporation equipment utilizes boiler flue gas and steam as heat sources.

3. The process for recovering the ethylene glycol raffinate through the immersion evaporation and adsorption as claimed in claim 1, wherein the immersion evaporation equipment adopts a straight tube type immersion evaporator, and comprises:

the wire mesh demister is arranged at the upper part of the evaporator and is used for removing mist generated by the action of air flow when the evaporator outputs evaporation tail gas;

the polytetrafluoroethylene heat exchanger is arranged at the bottom of the evaporator and is used for conveying steam to heat the evaporator;

the air inlet pipe is arranged on the wall of the evaporator and used for conveying the boiler flue gas into the evaporator so as to further heat the ethylene glycol residual liquid in the evaporator;

the liquid level meter is arranged on the outer wall of the evaporator and used for detecting the liquid level height in the evaporator in real time;

and the sampling port is arranged on the outer wall of the evaporator and is used for sampling the ethylene glycol treated in the evaporator at any time.

4. The process for recovering the ethylene glycol raffinate by the immersion evaporation adsorption as claimed in claim 3, wherein the immersion evaporation flow of the immersion evaporation equipment is as follows:

pumping residual ethylene glycol liquid into a straight pipe type immersion evaporator from a side inlet, enabling the liquid level displayed by the liquid level meter to reach 1/2, ensuring that vent holes at the bottom of the air inlet pipe are completely submerged below the liquid level, introducing boiler flue gas into the straight pipe type immersion evaporator through the air inlet pipe, filtering entrainment generated under the action of air flow through a wire mesh demister, and discharging tail gas from an outlet at the top of the evaporator;

opening an inlet and outlet valve of a polytetrafluoroethylene heat exchanger arranged in the bottom of the evaporator, and introducing steam for heating;

discharging the ethylene glycol residual liquid through an outlet at the bottom of the evaporator after the ethylene glycol residual liquid reaches the treatment time, and analyzing and sampling the treated ethylene glycol residual liquid through the sampling port;

when the device is used, the working efficiency of the evaporator is adjusted by the opening of the steam inlet and outlet valve of the bottom heat exchanger, and the treatment time is reduced by increasing the temperature of the ethylene glycol raffinate.

5. The process for recovering the ethylene glycol raffinate through the submerged evaporation adsorption as claimed in claim 4, wherein the heating temperature of the ethylene glycol raffinate in the submerged evaporation equipment is in the range of 80-120 ℃.

6. The process for recovering the ethylene glycol raffinate by the immersion evaporation adsorption as claimed in claim 4, wherein the flow rate of flue gas in the gas inlet pipeline is 600m³/h。

7. The process for recovering ethylene glycol raffinate by immersion evaporation adsorption as claimed in claim 4, wherein the steam inlet pressure in the immersion evaporation equipment is more than 0.4 MPa.

8. The process for recovering the ethylene glycol raffinate by the immersion evaporation adsorption as claimed in claim 1, wherein the activated carbon adopted by the activated carbon adsorption device has a micropore volume of 0.28cm³Per g, specific surface area 1500m²/g。

9. The process for recovering the ethylene glycol raffinate by the immersion evaporation adsorption according to claim 1, wherein the resin adopted by the ion exchange resin adsorption equipment is D311 macroporous resin, and the resin is subjected to immersion pretreatment by using 10% NaCl, 1mol/LHCl and 1mol/LNaOH solution before use.

10. The process for recovering the ethylene glycol raffinate through the immersion evaporation adsorption as claimed in claim 1, wherein the pH of the concentrated solution is greater than or equal to 6 after the concentrated solution is adsorbed and subjected to acidity adjustment through the ion exchange resin.

Technical Field

The invention relates to the technical field of ethylene glycol raffinate recovery, in particular to a process for recovering ethylene glycol raffinate through immersion, evaporation and adsorption.

Background

With the rapid development of industry, the treatment of industrial waste liquid becomes a problem which needs to be solved urgently in the field of environmental protection. China is a large ethylene glycol consuming country, in recent years, more and more coal-to-ethylene glycol projects are continuously on the horse, and ethylene glycol residual liquid becomes the treatment problem of the current chemical industry.

The ethylene glycol raffinate is a byproduct generated in the production process of coal-based ethylene glycol, wherein typical products, namely dimethyl oxalate, methyl glycolate and dimethyl carbonate, exist in the ethylene glycol raffinate, so that indexes such as color, smell, impurity content and ethylene glycol content of the ethylene glycol raffinate have large differences from refined ethylene glycol, the reutilization of resources is limited, and the waste of byproduct resources in the coal-based ethylene glycol industry chain is caused.

The current glycol raffinate mainly depends on reduced pressure distillation and a multi-stage rectifying tower for purification treatment, the process flow is complex, the energy consumption is generally large, the obtained concentrated glycol (85-98%) still has pungent smells such as caramel burnt smell due to the limitation of the distillation process, the product quality is reduced, the market price of the current glycol raffinate is far lower than that of tasteless concentrated glycol, and therefore, the research on refining recovery and quality improvement of the glycol raffinate has a potential huge profit space.

Chinese patent publication No.: CN103265401B discloses a recovery method of coal-made ethylene glycol raffinate, which contains methanol, ethanol, dimethyl carbonate, water, ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol and the like, and the recovery and component separation are carried out on the ethylene glycol raffinate by adopting a continuous and batch rectification method. It can be seen that the method has the following problems:

firstly, the method has the advantages of large energy consumption, similar boiling points of ethylene glycol raffinate components and large mass transfer resistance.

Second, the presence of dimethyl oxalate, methyl glycolate and dimethyl carbonate is produced when ethylene glycol raffinate is treated using the process, making the pH of the treated solution less than desired, with a noticeable pungent odor.

Disclosure of Invention

Therefore, the invention provides a process for recovering glycol raffinate by immersion, evaporation and adsorption, which is used for overcoming the problem of high energy consumption in the prior art.

In order to achieve the aim, the invention provides a process for recovering glycol raffinate by immersion, evaporation and adsorption, which comprises the following steps:

step 1: pumping the ethylene glycol raffinate into an immersion evaporation device, heating and evaporating to form a concentrated solution and evaporation tail gas, and conveying the concentrated solution to the next device by the immersion evaporation device for subsequent treatment and outputting the evaporation tail gas for post-treatment;

step 2: the immersion evaporation equipment conveys the concentrated solution to activated carbon adsorption equipment, the activated carbon adsorption equipment can adsorb and decolor the concentrated solution, the decolored concentrated solution is conveyed to next equipment for subsequent treatment, and gas mixed in the concentrated solution is discharged for post-treatment;

and step 3: the active carbon adsorption equipment conveys the decolored concentrated solution to ion exchange resin adsorption equipment, and after the concentrated solution enters the ion exchange resin adsorption equipment, the ion exchange resin can adsorb the concentrated solution and adjust the acidity of the concentrated solution to form a target product.

Further, the submerged evaporation apparatus utilizes boiler flue gas and steam as heat sources.

Further, the immersion evaporation apparatus adopts a straight tube type immersion evaporator, comprising:

the wire mesh demister is arranged at the upper part of the evaporator and is used for removing mist generated by the action of air flow when the evaporator outputs evaporation tail gas;

the polytetrafluoroethylene heat exchanger is arranged at the bottom of the evaporator and is used for conveying steam to heat the evaporator;

the air inlet pipe is arranged on the wall of the evaporator and used for conveying the boiler flue gas into the evaporator so as to further heat the ethylene glycol residual liquid in the evaporator;

the liquid level meter is arranged on the outer wall of the evaporator and used for detecting the liquid level height in the evaporator in real time;

and the sampling port is arranged on the outer wall of the evaporator and is used for sampling the ethylene glycol treated in the evaporator at any time.

Further, the immersion evaporation process of the immersion evaporation equipment is as follows:

pumping residual ethylene glycol liquid into a straight pipe type immersion evaporator from a side inlet, enabling the liquid level displayed by the liquid level meter to reach 1/2, ensuring that vent holes at the bottom of the air inlet pipe are completely submerged below the liquid level, introducing boiler flue gas into the straight pipe type immersion evaporator through the air inlet pipe, filtering entrainment generated under the action of air flow through a wire mesh demister, and discharging tail gas from an outlet at the top of the evaporator;

opening an inlet and outlet valve of a polytetrafluoroethylene heat exchanger arranged in the bottom of the evaporator, and introducing steam for heating;

discharging the ethylene glycol residual liquid through an outlet at the bottom of the evaporator after the ethylene glycol residual liquid reaches the treatment time, and analyzing and sampling the treated ethylene glycol residual liquid through the sampling port;

when the device is used, the working efficiency of the evaporator is adjusted by the opening of the steam inlet and outlet valve of the bottom heat exchanger, and the treatment time is reduced by increasing the temperature of the ethylene glycol raffinate.

Further, the heating temperature range of the ethylene glycol raffinate in the immersion evaporation equipment is 80-120 ℃.

Further, the flue gas flow in the gas inlet pipeline is 600m³/h。

Further, the pressure of a steam inlet in the immersion evaporation equipment is more than 0.4 MPa.

Further, the micropore volume of the activated carbon adopted by the activated carbon adsorption device is 0.28cm³Per g, specific surface area 1500m²/g。

Further, the resin adopted by the ion exchange resin adsorption equipment is D311 macroporous resin, and the resin is subjected to soaking pretreatment by using 10% NaCl, 1mol/LHCl and 1mol/LNaOH solution before use.

Further, after the ion exchange resin adsorbs and adjusts the acidity of the concentrated solution, the pH value of the concentrated solution is more than or equal to 6.

Compared with the prior art, the invention has the beneficial effects that the evaporation device used in the immersion evaporation process adopts the straight-tube type immersion evaporator, the high-temperature boiler flue gas is fully utilized to replace fuel gas as a power source, the treatment cost is reduced, simultaneously, the heat energy of the flue gas is recycled, simultaneously, the activated carbon and the ion exchange resin adopted by the invention can be reused after regeneration, and the unit treatment cost is reduced by more than 50% compared with a rectification method.

Furthermore, a wire mesh demister is arranged near the air outlet of the evaporator, mist mixed in the evaporation tail gas can be effectively removed by using a wire mesh, and the mist is intercepted inside the evaporator, so that the product amount in the evaporator is increased, and the operation efficiency of the process is improved.

In particular, the evaporator uses a polytetrafluoroethylene heat exchanger, and the heat in the system is recycled by transferring the heat of steam to heat the evaporator, so that the energy consumption of the process is reduced.

Particularly, the side wall of the evaporator is also provided with a liquid level meter, so that the liquid level in the evaporator can be confirmed in real time when the evaporator runs, the liquid level can be maintained at a specified value, the glycol residual liquid is immersed in the vent hole, and the running efficiency of the process is further improved.

Particularly, an air inlet is arranged in the evaporator, when the evaporator operates, boiler flue gas can be conveyed into the evaporator through the air inlet, so that the boiler flue gas and the ethylene glycol residual liquid are fully mixed and react with each other, and the operating efficiency of the evaporator is further improved.

Particularly, still be equipped with the sample connection in the evaporimeter, through carrying out sample detection with the concrete composition in the real-time detection evaporimeter to the material in the evaporimeter to guarantee that the material can the steady operation in the evaporimeter, further improved the operating efficiency of technology.

Furthermore, the process is also provided with activated carbon adsorption equipment, and the color and pungent smell of the concentrated solution after reaction can be effectively removed by using the activated carbon in the activated carbon adsorption equipment, so that the operation efficiency of the process is further improved.

Furthermore, the process is also provided with ion exchange resin adsorption equipment, and the recovery of the ethylene glycol raffinate is rapidly completed by adjusting the acidity of the concentrated solution by using the ion exchange resin, so that the operation efficiency of the process is further improved.

Drawings

FIG. 1 is a schematic structural view of the immersion evaporation apparatus according to the present invention;

FIG. 2 is a process flow diagram of the process for recovering ethylene glycol raffinate by immersion, evaporation and adsorption.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 is a schematic structural diagram of an immersion evaporation apparatus according to the present invention, including a wire mesh demister 1, a ptfe heat exchanger 2, an air inlet pipe 3, a liquid level meter 4, and a sampling port 5. The wire mesh demister 1 is arranged at the top end inside the evaporator and used for removing mist generated by air flow when the evaporator outputs evaporation tail gas. The polytetrafluoroethylene heat exchanger 2 is arranged at the bottom end inside the evaporator and used for absorbing heat of steam inside the polytetrafluoroethylene heat exchanger 2 to heat ethylene glycol raffinate. The air inlet pipe 3 is arranged on the side wall of the evaporator and positioned above the polytetrafluoroethylene heat exchanger 2 and used for conveying boiler flue gas to the interior of the evaporator, and the boiler flue gas is fully reacted with ethylene glycol residual liquid to form concentrated liquid while further heating the ethylene glycol residual liquid. The liquid level meter 4 is arranged on the side wall of the evaporator and is used for observing the height of the materials in the evaporator in real time. The sampling port 5 is arranged on the side wall of the evaporator and positioned above the polytetrafluoroethylene heat exchanger 2 and is used for sampling and analyzing materials in the evaporator.

When the immersion evaporation equipment is operated, pumping ethylene glycol raffinate into a straight-tube type immersion evaporator from a feed inlet on the side wall of an evaporator, enabling the liquid level displayed by the liquid level meter 4 to reach 1/2, ensuring that vent holes at the bottom of the air inlet pipe 3 are completely submerged below the liquid level, after the ethylene glycol raffinate is pumped, introducing boiler flue gas into the straight-tube type immersion evaporator through the air inlet pipe 3, filtering the boiler flue gas through a wire mesh demister 1 under the action of air flow, and discharging tail gas from an outlet at the top of the evaporator; when the evaporator operates, opening an inlet and outlet valve of a polytetrafluoroethylene heat exchanger 2 arranged in the bottom of the evaporator, and introducing steam for heating; discharging the ethylene glycol residual liquid through an outlet at the bottom of the evaporator after the ethylene glycol residual liquid reaches the treatment time, and analyzing and sampling the treated ethylene glycol residual liquid through the sampling port 5; when the device is used, the working efficiency of the evaporator is adjusted by the opening of the steam inlet and outlet valve of the bottom heat exchanger, and the treatment time is reduced by increasing the temperature of the ethylene glycol raffinate.

FIG. 2 is a flow chart of a process for recovering ethylene glycol raffinate by immersion, evaporation and adsorption according to the present invention. The method comprises the following steps:

step 1: pumping the ethylene glycol raffinate into an immersion evaporation device, heating and evaporating to form a concentrated solution and evaporation tail gas, and conveying the concentrated solution to the next device by the immersion evaporation device for subsequent treatment and outputting the evaporation tail gas for post-treatment;

step 2: the immersion evaporation equipment conveys the concentrated solution to activated carbon adsorption equipment, the activated carbon adsorption equipment can adsorb and decolor the concentrated solution, the decolored concentrated solution is conveyed to next equipment for subsequent treatment, and gas mixed in the concentrated solution is discharged for post-treatment;

and step 3: the active carbon adsorption equipment conveys the decolored concentrated solution to ion exchange resin adsorption equipment, and after the concentrated solution enters the ion exchange resin adsorption equipment, the ion exchange resin can adsorb the concentrated solution and adjust the acidity of the concentrated solution to form a target product.

Specifically, the heating temperature range of the ethylene glycol raffinate in the immersion evaporation equipment is 80-120 ℃; the flow of flue gas in the gas inlet pipeline is 600m³H; the pressure of a steam inlet in the immersion evaporation equipment is more than 0.4 MPa; the micropore volume of the active carbon adopted by the active carbon adsorption device is 0.28cm³Per g, specific surface area 1500m²(ii)/g; the resin adopted by the ion exchange resin adsorption equipment is D311 macroporous resin, and before the resin is used, 10% NaCl, 1mol/LHCl and 1mol/LNaOH solution are used for soaking pretreatment; after the ion exchange resin adsorbs and adjusts the acidity of the concentrated solution, the pH value of the concentrated solution is more than or equal to 6.

Specifically, in the process of carrying out submerged evaporation on the ethylene glycol raffinate by the submerged evaporation equipment, due to the existence of a large amount of water, dimethyl oxalate in the ethylene glycol raffinate is hydrolyzed to generate oxalic acid and methanol, methyl glycolate is hydrolyzed to generate glycolic acid and methanol, the color of the concentrated ethylene glycol is deepened due to the generation of glycolic acid, the acidity of the concentrated ethylene glycol is reduced due to the addition of an acidic substance, and meanwhile, the hydrolysis reaction is carried out on dimethyl oxalate, methyl glycolate and dimethyl carbonate in the ethylene glycol raffinate, so that the pungent smell is eliminated.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.