阅读说明：本技术 一种回收莱赛尔纤维生产排气中nmmo的装置及方法和应用 (Device and method for recovering NMMO in exhaust gas generated in lyocell fiber production and application ) 是由 孙华鹏 孙维坤 李永威 刘海星 韩荣桓 于 2019-09-12 设计创作，主要内容包括：本发明涉及莱赛尔纤维制备技术领域,尤其涉及一种回收莱赛尔纤维生产排气中NMMO的装置及方法和应用。所述装置包括：风房中从进风口至出风口段依次设置有初效过滤器、第一表冷器、中效过滤器、亚高效过滤器,风房的出风口、加压风机、预热塔的进口依次连接,预热塔中从进口至出口段依次设置有第二表冷器、加热器；吹风管与预热塔出口连接,回风管的入口正对吹风管的出口设置,回风管出口、回风风机、旋流板塔入口依次连接,旋流板塔中从进口至出口段依次设置有冷凝水喷头、除雾器；旋流板塔的出口与酸洗涤塔的入口连接,酸洗涤塔中设置有酸液喷头。本发明的方法能够有效实现工艺风中NMMO的回收,提高了NMMO的利用率。(The invention relates to the technical field of preparation of lyocell fibers, in particular to a device and a method for recovering NMMO (N-methyl-MO) in exhaust gas generated in the production of lyocell fibers and application of the device. The device comprises: the air outlet of the air room, the pressurizing fan and the inlet of the preheating tower are sequentially connected, and the preheating tower is sequentially provided with a second surface air cooler and a heater from the inlet to the outlet section; the air blowing pipe is connected with the outlet of the preheating tower, the inlet of the return air pipe is arranged right opposite to the outlet of the air blowing pipe, the outlet of the return air pipe, the return air fan and the inlet of the rotational flow plate tower are sequentially connected, and a condensed water spray head and a demister are sequentially arranged in the rotational flow plate tower from the inlet to the outlet section; the outlet of the cyclone plate tower is connected with the inlet of an acid washing tower, and an acid liquor spray head is arranged in the acid washing tower. The method can effectively realize the recovery of the NMMO in the process wind and improve the utilization rate of the NMMO.)

1. An apparatus for recovering NMMO in exhaust gas from lyocell fiber production, comprising: wind room, primary filter, first surface cooler, well effect filter, inferior high efficiency filter, booster fan, second surface cooler, heater, blowing pipe, return air fan, whirl board tower, condensation water shower nozzle, defroster, acid wash tower and acidizing fluid shower nozzle, wherein:

the air room is sequentially provided with a primary filter, a first surface cooler, a medium-efficiency filter and a sub-high-efficiency filter from an air inlet to an air outlet section, the air outlet of the air room, a pressurizing fan and the inlet of the preheating tower are sequentially connected, and the preheating tower is sequentially provided with a second surface cooler and a heater from the inlet to the outlet section; the blowing pipe is connected with the outlet of the preheating tower, the inlet of the return air pipe is arranged right opposite to the outlet of the blowing pipe, the outlet of the return air pipe, the return air fan and the inlet of the rotational flow plate tower are sequentially connected, and a condensed water spray head and a demister are sequentially arranged in the rotational flow plate tower from the inlet to the outlet section; the outlet of the cyclone plate tower is connected with the inlet of an acid washing tower, and an acid liquor spray head is arranged in the acid washing tower.

2. The apparatus for recovering NMMO from lyocell process exhaust gas of claim 1, wherein said condensate spray head is connected to a condenser through a pipe; preferably, the condenser is connected to the first surface cooler.

3. The apparatus for recovering NMMO from lyocell fibre production exhaust of claim 1 in which the base of said cyclone plate tower is connected to a coagulation bath; preferably, the lower part of the acid washing tower is communicated with an acid liquor spray head.

4. The apparatus for recovering NMMO from lyocell fiber production exhaust gas of claim 1, wherein the lower portion of said acid washing tower is connected to a waste liquid treatment tank; preferably, the air inlet of the air room is connected with the non-woven fabric filter bag.

5. The apparatus for recovering NMMO from lyocell process exhaust gases of any one of claims 1 to 4, further including a preheater disposed between the primary filter and the first surface cooler.

6. A method for recovering NMMO in exhaust gas from lyocell fiber production, comprising the steps of:

(1) the outdoor air enters an air room through a non-woven fabric filter bag, is coarsely filtered by a primary filter and then enters a first surface air cooler to recover water vapor in the air;

(2) the air after being dewatered is further treated by a middle-effect filter and a sub-high-effect filter to remove particles in the air and then enters a pressurizing fan; the temperature rises after the air is pressurized, and the temperature is adjusted by the second surface air cooler and the heater to reach the process using condition, so that the process air is obtained;

(3) the process air is delivered to a spinning machine, the temperature and the humidity of the process air are increased after passing through a spinning curtain, the process air carries NMMO solvent to enter a return air pipe, the return air enters a return air fan to be pressurized and then is sent into a cyclone plate tower for air, and then is contacted with a condensate water film, so that the NMMO is dissolved in water, and the recovery of the NMMO is realized;

(4) and carrying water mist with the process air after NMMO recovery, demisting the process air by a demister in the cyclone plate tower, then sending the process air into an acid washing tower for acid washing, and emptying the process air after the acid washing.

7. The method of recovering NMMO in lyocell fiber process exhaust according to claim 6, wherein in step (1), the process air is passed through a 300um stainless steel screen for final filtration before being delivered to the spinning machine;

preferably, in the step (3), the return air volume is 2-2.5 times of the supply air volume;

preferably, in step (3), the condensed water is provided by a water meter condenser or a thin film evaporator;

preferably, in the step (3), the condensed water is desalted water and is obtained after heat exchange through a condenser;

preferably, in the step (3), the temperature of the water in the cyclone plate tower is controlled between 10 and 25 ℃, and more preferably 15 ℃.

8. The method for recovering NMMO from lyocell process exhaust gas according to claim 6, wherein in step (4), the acid used for acid washing is a sparingly volatile acid; preferably sulfuric acid; preferably, the pH of the acid is 2-3.

9. The method for recovering NMMO in lyocell fiber production exhaust gas according to any one of claims 6 to 8, wherein step (4) further includes the steps of: the air is pre-heated by a pre-heater after being coarsely filtered by a primary filter, and then enters a first surface air cooler to recover water vapor in the air.

10. Use of the device for recovering NMMO in lyocell process exhaust gases according to any of claims 1 to 5 and/or the method according to any of claims 6 to 9 in the chemical industry.

Technical Field

The invention relates to the technical field of preparation of lyocell fibers, in particular to a device and a method for recovering NMMO (N-methyl-MO) in exhaust gas generated in the production of lyocell fibers and application of the device.

Background

The information disclosed in this background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

N-methylmorpholine oxide (NMMO) is a nontoxic harmless environment-friendly solvent, the International rayon standardization organization (BISFA for short) names regenerated cellulose fibers produced by an organic solvent dissolving method as Lyocell (Chinese Lyocell), the Lyocell fibers are novel cellulose fibers produced by dissolving cellulose pulp in an NMMO aqueous solution and performing dry-wet spinning without chemical reaction, the mechanical property of the Lyocell fibers is excellent, the Lyocell fibers have the comfort of cotton fibers and the strength of terylene, the Lyocell fibers are green fibers, the raw materials of the Lyocell fibers are inexhaustible cellulose in nature, and the waste can be biodegraded. Because the temperature of the spinning stock solution is higher and the viscosity is very high in the spinning process, the spinning stock solution passes through a spinneret plate to spin a silk curtain, and then enters a coagulating bath through a section of air gap to obtain an excellent fiber structure.

Disclosure of Invention

The inventor finds that: in the cooling process of the filament curtain, the moisture content and the temperature of fresh air are increased after passing through the filament curtain, and a part of NMMO solvent is entrained and discharged into the atmosphere, although the NMMO is nontoxic and harmless, the volume ratio of the NMMO solvent contained in each cubic meter of air is calculated to reach 0.55%, and the production cost can be greatly reduced if the NMMO solvent can be recycled. In view of the above problems, the present invention aims to provide a device and a method for recovering NMMO in exhaust gas from lyocell fiber production, and applications thereof. The invention not only can effectively recover NMMO in exhaust gas and realize higher resource utilization rate, but also effectively improves the environment of a spinning room.

The first object of the present invention: provides a device for recovering NMMO in exhaust gas generated in the production of lyocell fibers.

The second object of the present invention: a method for recovering NMMO from lyocell process exhaust is provided.

The third object of the present invention: the application of the device and the method for recovering NMMO in exhaust gas generated in the production of lyocell fibers is provided.

In order to realize the purpose, the invention discloses the following technical scheme:

first, the present invention discloses a device for recovering NMMO in exhaust gas from lyocell fiber production, comprising: wind room, primary filter, pre-heater, first surface cooler, well high efficiency filter, booster fan, second surface cooler, heater, blowing pipe, return air fan, whirl board tower, condensation water shower nozzle, defroster, acid wash tower and acidizing fluid shower nozzle, wherein:

the air room is sequentially provided with a primary filter, a preheater, a first surface air cooler, a medium-efficiency filter and a sub-high-efficiency filter from an air inlet to an air outlet section, the air outlet of the air room, a pressurizing fan and an inlet of a preheating tower are sequentially connected, and a second surface air cooler and a heater are sequentially arranged in the preheating tower from the inlet to an outlet section; the blowing pipe is connected with the outlet of the preheating tower, the inlet of the return air pipe is arranged right opposite to the outlet of the blowing pipe, the outlet of the return air pipe, the return air fan and the inlet of the rotational flow plate tower are sequentially connected, and a condensed water spray head and a demister are sequentially arranged in the rotational flow plate tower from the inlet to the outlet section; the outlet of the cyclone plate tower is connected with the inlet of an acid washing tower, and an acid liquor spray head is arranged in the acid washing tower.

Secondly, the invention discloses a method for recovering NMMO in exhaust gas generated in the production of lyocell fibers, which comprises the following steps:

(1) outdoor air enters an air room through a non-woven fabric filter bag, is pre-heated by a pre-heater (the air is started when the outside air temperature is low in winter and can be closed at other time) after being pre-filtered by a primary filter, and then enters a first surface air cooler to recover water vapor in the air so as to be supplied to a cyclone plate tower for use; especially when the air humidity is big, the use of once surface cooler has both effectively utilized the steam in the air, has satisfied the requirement of silk curtain to the air again.

(2) The air after being dewatered is further treated by a middle-effect filter and a sub-high-effect filter to remove particles in the air and then enters a pressurizing fan; and (4) adjusting the temperature by the second surface air cooler and the heater to reach the process using condition due to the fact that the temperature rises after the air is pressurized, and obtaining the process air.

(3) The process air is delivered to a spinning machine, the temperature and the humidity of the process air are increased after the process air passes through a spinning curtain, the process air carries an NMMO solvent to enter a return air pipe, the return air enters a return air fan to be pressurized and then is sent to air of a cyclone plate tower and then is contacted with a condensate water film, so that the NMMO is dissolved in water, the recovery of the NMMO is realized, the NMMO in the process air is prevented from being decomposed at high temperature for a long time, and the recovery utilization rate is improved.

(4) And demisting the process air carrying water mist after the NMMO is recovered by a demister in the cyclone plate tower, and then sending the process air into an acid washing tower for acid washing so as to remove alkaline gas carried in the process air, and emptying the process air after the acid washing.

Finally, the invention discloses application of the device for recovering NMMO in exhaust gas in lyocell fiber production in the fields of chemical industry and the like.

Compared with the prior art, the invention has the following beneficial effects:

(1) the device and the method provided by the invention can effectively realize the recovery of the NMMO in the process wind, improve the utilization rate of the NMMO and avoid waste.

(2) Aiming at the purpose of recovering the NMMO in the process air and the characteristic that the NMMO can be decomposed at high temperature, the invention specially introduces the condensed water into the cyclone plate tower, so that firstly, the condensed water can absorb the NMMO in the process air to realize the recovery of the NMMO, and secondly, the ambient temperature in the cyclone plate tower can be effectively reduced, the decomposition of the NMMO is reduced as much as possible, and the recovery rate of the NMMO is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

Fig. 1 is a schematic structural view of an apparatus for recovering NMMO in exhaust gas from lyocell fiber production in example 1 of the present invention.

Fig. 2 is a schematic structural view of an apparatus for recovering NMMO in lyocell fiber production exhaust gas in embodiment 2 of the present invention.

The reference numerals in the drawings denote: 1-wind room, 2-primary filter, 3-preheater, 4-first surface cooler, 5-intermediate filter, 6-sub-high efficiency filter, 7-pressurizing fan, 8-second surface cooler, 9-heater, 10-blowing pipe, 11-air return pipe, 12-air return fan, 13-cyclone plate tower, 14-condensed water spray head, 15-demister, 16-acid washing tower, 17-acid liquor spray head and 18-condenser.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms also are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should be further understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, devices, components, and/or combinations thereof.

As previously mentioned, the cooling of the screen, in which fresh air passes through the screen, increases in moisture content and temperature and entrains a portion of the NMMO solvent to be vented to the atmosphere, would greatly reduce production costs if it could be recycled. Therefore, the invention provides a device and a method for recovering NMMO in exhaust gas in lyocell fiber production based on electroplating wastewater.

In some exemplary embodiments, the air inlet of the air chamber is connected to a non-woven fabric filter bag to pre-filter air.

In some exemplary embodiments, the condensate spray head is connected to the condenser through a pipe.

In some exemplary embodiments, the condenser is connected to the first surface cooler, and after the outdoor air passes through the first surface cooler, moisture in the outdoor air is condensed and then enters the condenser to be used as supplementary cooling water, so that the moisture in the outdoor air is fully utilized.

In some exemplary embodiments, the bottom of the cyclone plate tower is connected with a coagulation bath, and the NMMO in the air after being cooled in the cyclone plate tower falls into the bottom of the cyclone plate tower along with condensed water, and then is guided into the coagulation bath to be continuously used for the production of lyocell fibers, so that the recovery and utilization of the NMMO in the air are realized.

In some exemplary embodiments, the lower part of the acid washing tower is communicated with the acid liquor spray head so as to realize the recycling of the acid liquor, and since partial decomposition of NMMO can form alkaline gas, the acid washing tower is arranged to remove the alkaline gas in order to avoid polluting air after direct discharge.

In some exemplary embodiments, the lower portion of the acid wash tower is connected to a sump treatment tank to facilitate draining of sump from the bottom of the acid wash tower for treatment when needed.

In some exemplary embodiments, in step (1), the process air is delivered to the spinning machine and then filtered through a 300um stainless steel mesh sheet.

In some exemplary embodiments, in step (3), the return air volume is 2 to 2.5 times the supply air volume.

In some exemplary embodiments, in step (3), the condensed water is provided by a water meter condenser or a thin film evaporator so as to ensure that the temperature of the condensed water is lower.

In some exemplary embodiments, in step (3), the condensed water is desalted water and is obtained after heat exchange of the desalted water by a condenser.

In some exemplary embodiments, in step (3), the temperature of the water in the cyclone plate tower is preferably controlled to be between 10 and 25 ℃, preferably 15 ℃.

In some exemplary embodiments, in step (4), the acid used for the acid washing is a sparingly volatile acid; preferably sulfuric acid; optionally, the acid has a pH of 2-3.

The invention will now be further described with reference to the accompanying figures 1-2 and the detailed description.