CN101816843A - Device and method for extracting acephate from neutralization solution - Google Patents

Abstract

The invention discloses a device and a method for extracting acephate from neutralization solution. The device comprises a tower body, a material filling section, a light phase sparger and the like, wherein an interphase impurity collector is arranged between the bottom part of the material filling section and the light phase sparger; and the expanded section at the bottom of the tower is connected with an interphase impurity discharge device. In the method, a filled extraction tower is used to extract the acephate from the neutralization solution, the interphase impurity collector collects interphase impurities mainly produced on the bottom part of the material filling section, and the interphase impurity discharge device discharges the impurities periodically. The device and the method, which are disclosed in the invention, can prevent the interphase impurities from rising with the neutralization solution so as not to pollute the whole material filling section and can relieve the influences of the interphase impurities on an extraction process and improve extraction efficiency. Meanwhile, the device and the method can avoid stopping work frequently for discharging the impurities or washing the tower and can meet needs for continuous mass production.

Description

A device and method for extracting acephate from neutralization liquid

technical field

The invention belongs to the extraction technology of organic pesticides, in particular to a device and method for extracting acephate from a neutralization liquid.

Background technique

Acephate, chemical name O, S-dimethyl-N-acetylthiophosphoramide, is an acetylated derivative of the organophosphorus insecticide methamidophos. Acephate is a systemic contact insecticide with high efficiency, low toxicity and low residue, and its toxicity is only one-fiftieth of that of methamidophos. It is easy to biodegrade in nature and will not accumulate in animals. With the feature of not polluting the environment, it may become a main organophosphorus pesticide to replace methamidophos. Today, when pesticides are developing from high toxicity to low toxicity, it will be an ideal variety, and its application range and market prospects are very broad.

At present, the production of acephate in China generally uses O, S-dimethylphosphorothioate as raw material to synthesize acephate through transposition and acetylation processes, and then use ammonia water to neutralize the acylation solution to obtain neutralization liquid, and then use an organic solvent to extract and separate acephate from the neutralized liquid, and the extract is subjected to processes such as precipitation, crystallization, and drying to obtain acephate crystals with a purity of more than 97%. The synthesis technology of this process is relatively mature, but there are still some problems in the subsequent extraction operation, which are specifically manifested in:

(1) Some manufacturers use 4 mixing and settling tanks to extract 4 times, and some manufacturers use 3 static mixers to extract three times, and then 1 centrifugal extractor to extract once, so that the obtained extract contains acephate each time The large difference in concentration will make subsequent desolvation and other operations unstable, thereby making the quality of the final product unstable.

(2) Some manufacturers use multi-stage centrifugal extractors for extraction, which will produce crystallization, block the centrifugal extractors, cause serious damage to the equipment, and frequent maintenance will affect production. In addition, due to the high-speed rotation of the drum, the energy consumption is relatively high.

(3) The extraction operation is complicated, so that the residual concentration of acephate in the raffinate is relatively high.

Patent ZL200610113741.6 discloses a device and method for extracting acephate from neutralization liquid. As shown in Figure 1, the device is a packed extraction tower, which consists of a tower body, packing, packing limit plate, packing support plate, liquid distributor and redistributor; there is a raffinate outlet 1 at the top of the tower body, and a raffinate outlet 1 at the bottom. Extraction liquid outlet 10, extractant inlet 2 above the packing limiting plate 5 of the tower body, neutralizing liquid inlet 9 below the packing supporting plate 8 of the tower body, packing is installed between the packing limiting plate 5 and the packing supporting plate 8 7. There are liquid distributors 4 at the extraction agent inlet 2 and neutralizing liquid inlet 9, and a liquid redistributor 6 in the packing section. The method disclosed in this patent is to use the organic phase as the continuous phase and the water phase as the dispersed phase to extract acephate from the neutralization solution by utilizing the above-mentioned device. This device can solve the problem of crystallization clogging the centrifugal extractor, but this patented device and method encountered a new problem when it was popularized and applied to the pesticide manufacturers of continuous large-scale production: after the new tower ran for two days (48h), the top of the tower The concentration of acephate contained in the export extract is much higher, which will reach 4-6%. This is because the solvent used for extraction is generally dichloromethane or chloroform, and more interface dirt will be generated during extraction. This kind of interface dirt mainly occurs in the lower part of the packing section (where the water phase just enters the tower), and rises along the tower to the top interface of the tower, thus polluting the entire packing section of the tower. And because the interface dirt is hydrophilic, it is easy to adhere to the surface of the filler, so the water droplets as the dispersed phase are wetted into streams or channels, which greatly reduces the interface area of the two phases, resulting in a decrease in mass transfer and extraction efficiency. For the problem that the interface dirt affects the extraction efficiency, the interface dirt can only be discharged from the outlet of the raffinate at the top of the tower by stopping the tower, and the effect is very poor. Later, this problem was alleviated by frequent washing of the tower with hot water, but it was still difficult to solve it fundamentally. What's more, frequent tower washing is really unacceptable for manufacturers with continuous large-scale production.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device and method for extracting acephate from the neutralization liquid, which can prevent the interface dirt from polluting the entire packing section and improve the extraction efficiency.

In order to solve the above-mentioned technical problems, the extraction device provided by the present invention includes: an extraction tower body; a packing section is arranged in the extraction tower body; a raffinate outlet is arranged at the top of the tower body, and a tower bottom is provided at the bottom of the tower body. There is an extractant outlet at the bottom of the expansion section at the bottom of the tower; there is an extractant inlet above the packing section; there is a neutralizing liquid inlet below the packing section, and there is a neutralizing liquid inlet below the packing section. There is a light phase distributor in between; an interface dirt collector is provided between the bottom of the packing section and the light phase distributor; the expansion section at the bottom of the tower is connected with an interface dirt discharge device.

Since the device includes an interface dirt accumulator and an interface dirt removal device, the interface dirt mainly generated at the bottom of the packing section can be collected through the interface dirt collector, thereby preventing the interface dirt from moving up with the water phase. Contaminate the entire packing section, so it can reduce the impact of interface dirt on the extraction process and improve extraction efficiency.

The invention also discloses a method for extracting acephate from the neutralization solution. The method comprises the following steps: the extractant enters the tower through the extractant inlet on the upper part of the extraction tower body, is dispersed by a heavy phase distributor and then moves down; the neutralization liquid containing acephate enters the tower from the neutralization liquid inlet at the bottom of the extraction tower , and flow upward through the light phase distributor, contact with the extractant countercurrently, and extract; while extracting, the generated interface dirt is aggregated, and the accumulated interface dirt moves down with the extractant It enters the tower bottom expansion section at the bottom of the extraction tower body.

Using the above method for extraction, since the interface dirt accumulator gathers the interface dirt mainly generated at the bottom of the packing section, and regularly discharges the interface dirt through the interface dirt discharge device, it can prevent the interface dirt from rising with the water phase and pollute the whole The packing section eliminates the need for frequent shutdowns to wash the tower; it also ensures high extraction efficiency, making continuous operation possible. Continuous operation can make the operation of the tower very stable, including the concentration of the aqueous phase and the organic phase of the raffinate at the outlet of the tower are very stable, so that the subsequent desolvation and other operations are stable and finally achieve the purpose of stabilizing the product quality. Especially when the output of neutralizing liquid is large, the continuous extraction operation has greater advantages.

Description of drawings

Fig. 1 is the device structural representation of extracting acephate from neutralizing liquid in the prior art;

Fig. 2 is a schematic structural diagram of a device for extracting acephate from a neutralization solution according to an embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

The invention discloses a device for extracting acephate from a neutralization liquid, comprising: an extraction tower body;

A packing section is arranged in the tower body of the extraction tower; a raffinate outlet is arranged at the top of the tower body, a bottom expansion section is arranged at the bottom of the tower body, and an extraction liquid outlet is arranged at the bottom of the expansion section at the bottom of the tower; in the packing section There is an extractant inlet above the top of the packing section; there is a neutralizing liquid inlet below the packing section, and there is a light phase distributor between the bottom of the packing section and the neutralizing liquid inlet; at the bottom of the packing section and the light phase An interface dirt collector is arranged between the phase distributors; the expansion section at the bottom of the tower is connected with an interface dirt discharge device.

Since the device includes an interface dirt accumulator and an interface dirt removal device, the interface dirt mainly generated at the bottom of the packing section can be collected through the interface dirt collector, thereby preventing the interface dirt from moving up with the water phase. Contaminate the entire packing section, so it can reduce the impact of interface dirt on the extraction process and improve extraction efficiency.

In order to make the extraction agent in the tower, that is, the organic phase, more evenly distributed, there is a heavy phase distributor between the top of the packing section and the inlet of the extractant, and a heavy phase redistributor is installed in the middle of the packing layer.

In order to observe the thickness of the interface dirt accumulated in the expansion section at the bottom of the tower, the device is equipped with an observation device for the thickness of interface dirt in the expansion section at the bottom of the extraction tower.

In order to discharge the interface dirt, the interface dirt discharge device includes an interface dirt discharge pipe connected to the expansion section at the bottom of the tower, and an interface dirt temporary storage device connected to the interface dirt discharge pipe.

In order to recover the extract, the device also includes an extract recovery device connected to the lower part of the interface dirt temporary storage device through a pipeline; an interface dirt and raffinate collection and storage device connected to the interface through a pipeline The upper part of the temporary storage device for dirt is connected.

In order to ensure full contact between the extractant and the neutralizing solution, the packing is a multi-layer orifice corrugated structured packing.

The device for extracting acephate from the neutralization solution shown in FIG. 2 is a specific embodiment of the device disclosed in the present invention. As shown in Figure 2, the packed extraction tower consists of an extraction tower body 17, a packing 7, a packing limiter 10, a packing support plate 8, a light phase liquid distributor 2, a heavy phase liquid distributor 5, and a heavy phase liquid redistributor 9 and sight glass 11, interface dirt collector 19, interface display and controller 12, interface dirt discharge pipe 13, interface dirt clarification tank 14, clarification tank interface meter 18, interface dirt and light phase liquid temporary storage tank 15. The precipitation heavy phase temporary storage tank 16 and other components. The diameter of the packed extraction tower is 1000mm, the height of the packing layer in the tower is 10m, the diameter of the enlarged end of the top and bottom of the tower is 1.3m, and the height is 1.7m. The density is 250m ² /m ³ , the porosity is 95%, the height of each layer of packing is 110 mm, and the arrangement angle of two adjacent packing layers is 85-95°. The specification of a pair of mirrors 11 is Ф150mm, the specification of the interface display and controller L=1200, and the specification of the interface dirt discharge pipe is Ф32mm.

Due to the installation of the interface dirt accumulator and the interface dirt discharge device, it can prevent the interface dirt from rising with the neutralizing liquid and contaminate the entire packing section, without frequent shutdowns for sewage discharge or washing the tower with hot water, and the operation can be carried out continuously. This can make the operation of the extraction tower very stable, that is, the concentration of the raffinate at the outlet of the tower and the concentration of the organic phase are very stable, so that the subsequent desolvation and other operations are stable, and finally the purpose of stabilizing the product quality is achieved.

On the contrary, if no interface dirt accumulator and removal device are installed, after the new tower runs for two days (48h), the concentration of acephate in the extract at the outlet of the tower is much higher, which will reach 4-6%. After 24 hours of operation, the concentration of acephate in the extract at the outlet of the tower is still much higher, reaching 4.3%. This proves the remarkable superiority of the present invention from the negative side.

The invention also discloses a method for extracting acephate from the neutralization solution. The method comprises the following steps: the extractant enters the tower through the extractant inlet on the upper part of the extraction tower body, is dispersed by a heavy phase distributor and then moves down; the neutralization liquid containing acephate enters the tower from the neutralization liquid inlet at the bottom of the extraction tower , and flow upward through the light phase distributor, contact with the extractant countercurrently, and extract; while extracting, the generated interface dirt is aggregated, and the accumulated interface dirt moves down with the extractant It enters the tower bottom expansion section at the bottom of the extraction tower body.

Using the above method to extract acephate from the neutralization solution, since the interface dirt collector will gather the interface dirt mainly generated at the bottom of the packing section, and the interface dirt will be discharged regularly through the interface dirt discharge device, which can prevent the interface dirt The substance rises with the water phase and pollutes the entire packing section, so that there is no need to stop washing the tower frequently; it can also ensure high extraction efficiency, making continuous operation possible. Continuous operation can make the operation of the tower very stable, including the concentration of the aqueous phase and the organic phase of the raffinate at the outlet of the tower are very stable, so that the subsequent desolvation and other operations are stable and finally achieve the purpose of stabilizing the product quality. Especially when the output of neutralizing liquid is large, the continuous extraction operation has greater advantages.

The said collecting the generated interface dirt while extracting includes: collecting the interface dirt through the interface dirt collector arranged between the bottom of the packing section and the light phase distributor while extracting Gather.

Said making the accumulated interface dirt move down with the extractant into the tower bottom expansion section at the bottom of the extraction tower body comprises: making the interface dirt accumulate in the expansion section at the bottom of the tower, and after accumulating to Discharge after a certain thickness.

The step of discharging the interface dirt after accumulating to a certain thickness in the expanded section at the bottom of the tower includes: opening the valve of the interface dirt discharge pipeline, discharging the interface dirt to the interface dirt temporary storage device; After being clarified in the interface dirt temporary storage device for a period of time, the extracted extract is recovered from the bottom of the interface dirt temporary storage device, and the interface dirt and raffinate are recovered from the upper part of the interface dirt temporary storage device Collect and store.

The extractant is dichloromethane, 1,2-dichloroethane, chloroform, 1,1,1-trichloroethane, trichloroethylene or a mixture of two or more of these halogenated hydrocarbons. The ratio of the flow rate of the extraction agent to the feed of the neutralizing liquid is 1.5-1.6:1, wherein the flow rate of the neutralizing liquid is 2.1-3.5 m ³ /h.

In the extraction process, the neutralizing liquid (ie, the water phase) is used as the continuous phase, and the extraction agent (ie, the organic phase) is used as the dispersed phase for extraction. Since the interface dirt is hydrophilic, even if part of the surface of the filler is polluted by the interface dirt, the organic liquid droplets as the dispersed phase will not be wetted on the surface of the filler to form streams or channels and can maintain the droplet shape, that is, still Can maintain a larger two-phase mass transfer area. Therefore, this method can maintain a large mass transfer interface area, thereby solving the problem that the interface dirt affects the extraction efficiency or the concentration of pesticides in the tower raffinate is too high.

The following is a specific embodiment of the method

Extract acephate from the neutralization liquid: In the extraction tower as shown in Figure 2, the water phase is used as the continuous phase and the organic phase is used as the dispersed phase for extraction; the extractant is pumped to the upper part of the tower through the organic phase feed The inlet 4 enters the tower through the distributor 5 and then moves down after being dispersed, passes through the structured packing section, and reaches the expansion section at the bottom of the tower; the neutralization liquid enters the tower from the inlet 1 at the bottom of the tower by the water-phase feed pump and flows upward slowly through the distributor 2, and The down-moving extractant is contacted in countercurrent, so as to achieve high-efficiency mass transfer. After the extract reaches the expansion section at the bottom of the tower, it is fully phase-separated and exits the tower through outlet 3; The interface dirt that mainly occurs at the bottom of the packing section (at the light phase liquid distributor 2) is prevented from rising by the interface dirt collector 19, and as the extractant reaches the expansion section at the bottom of the tower downwards, it prevents the interface dirt from rising. Pollution of the entire packing section; and the interface dirt is hydrophilic, even if part of the filler surface is polluted by the interface dirt, the droplets as the dispersed phase will not be wetted on the surface of the filler to form a stream and can maintain the droplet shape, that is It can still maintain a large two-phase mass transfer interface area, thereby ensuring high extraction efficiency. In this embodiment, the diameter of the extraction tower is 1000 mm, the total height of the packing is 10 m, the specific surface area of the orifice corrugated packing is 250 m ² /m ³ , and the lower part of the packing section of the tower body is equipped with an interface dirt collector 19 and an interface dirt removal device (as shown in Figure 2 shown). During this extraction operation, the ratio of the extraction agent to the feed flow of the neutralizing liquid was 1.5:1, the flow of the neutralizing liquid was 2.1 and 3.5 m ³ /h, and the concentration of acephate in the raffinate after extraction was less than 1.0 and 1.4 respectively. %, the extraction rate reaches 98.2 and 97.2% respectively, and the extraction efficiency is increased by 8% compared with the extraction tower disclosed in ZL200610113741.6, and the outlet concentration of acephate in the extract is 13-15%.

Eliminate the dirt on the interface: the thickness of the dirt on the interface was found to exceed 0.15m during continuous extraction for 6 days. Properly adjust the discharge flow rate of the outlet valve at the bottom of the tower so that the dirt on the interface can be adjusted to the central part that can be observed by the sight glass 11. Open the bottom of the tower The valve on the discharge interface dirt pipeline 13 discharges most of the interface dirt to the interface dirt clarification tank 14, and as a result discharges 200 liters of interface dirt. After clarification for a period of time, the separated heavy phase is put into the separated heavy phase temporary storage tank 16 from the bottom pipe of the clarification tank 14, and 100 liters of extractant is reclaimed as a result. Put the supernatant liquid into the temporary storage tank 15 for interface dirt and light phase liquid.

After the extraction operation is finished, stop feeding the water phase and the organic phase at the same time, stand still for about 10 minutes, and release part of the organic phase from the outlet 3 at the bottom of the tower to prevent the acephate in the high-concentration organic phase at the bottom of the tower from diffusing upward. When opening the tower next time, add fresh organic phase to adjust the interface to the normal position.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. All should be covered within the protection scope of the present invention. For example, whether the diameter of the packed extraction tower is greater than, equal to or less than 1000mm, whether the total height of the structured packing is greater than, equal to or less than 10m, and whether the flow rate of the neutralizing liquid to be treated is greater than, equal to or less than 2m ³ /h, as long as it is used Dichloromethane, 1,2-dichloroethane, chloroform, 1,1,1-trichloroethane, trichloroethylene or a mixture of two or more of these halogenated hydrocarbons can be used as the extractant The interface dirt accumulator and interface dirt removal device of the present invention, as well as the operation method of the present invention eliminate the influence of the interface dirt generated during extraction on the extraction efficiency, improve the extraction efficiency, and do not need to stop washing the tower, thereby realizing continuous Extract large production. Therefore, no matter whether the diameter of the extraction tower is large or small, the total height of the filler is large or small, and the neutralizing liquid treatment capacity is large or small, all should be within the protection scope of the present invention.

Claims (15)

1. One kind from neutralizer the extraction orthene device, comprising:

   The extraction tower tower body;

   In described extraction tower tower body, be provided with packing section;

   Raffinate outlet is arranged at described tower body top, and the tower body bottom has expanding reach at the bottom of the tower, and the bottom of expanding reach has the extract outlet at the bottom of tower;

   The extractant inlet is arranged above described packing section;

   The neutralizer inlet is arranged below described packing section, below the described packing section with between the neutralizer inlet light distributor is mutually being arranged;

   It is characterized in that, at the bottom and the described light interphase impurity collector that is provided with between the distributor mutually of described packing section;

   Expanding reach is connected with the interphase impurity discharger at the bottom of the described tower.
2. 2. the device that extracts orthene from neutralizer as claimed in claim 1 is characterized in that,

   Described interphase impurity discharger comprises: interphase impurity discharge pipe that is connected with expanding reach at the bottom of the described tower and the interphase impurity apparatus for temporary storage that links to each other with this interphase impurity discharge pipe.
3. 3. the device that extracts orthene from neutralizer as claimed in claim 2 is characterized in that described device also comprises:

   The extract retracting device links to each other by the bottom of pipeline with described interphase impurity apparatus for temporary storage;

   Interphase impurity and raffinate storage device link to each other by the top of pipeline with described interphase impurity apparatus for temporary storage.
4. 4. as claim 1, the 2 or 3 described devices that from neutralizer, extract orthene, it is characterized in that, interphase impurity thickness finder is housed on expanding reach at the bottom of the described extraction Tata.
5. 5. the device that extracts orthene from neutralizer as claimed in claim 1 is characterized in that,

   Above the described packing section and between the extractant inlet heavy phase distributor is being arranged;

   In the middle of described packing section, be provided with the heavy phase redistributor.
6. 6. the device that extracts orthene from neutralizer as claimed in claim 1 is characterized in that,

   Filler in the described packing section is the perforated plate ripple arranged packing, and specific area is 250m ²/ m ³, voidage is 95%.
7. 7. the device that extracts orthene from neutralizer as claimed in claim 1 is characterized in that every layer of packed height in the described packing section is 110 millimeters, and adjacent two packing layer arrangement angle are 85～95 °.
8. 8. the device that extracts orthene from neutralizer as claimed in claim 1 is characterized in that the total height of filler is 10 meters in the described packing section.
9. 9. the method for an extraction orthene from neutralizer is characterized in that, may further comprise the steps:

   Extractant enters the mouth into tower through extraction tower tower body top extractant, moves down after disperseing through the heavy phase distributor;

   The neutralizer that contains orthene is entered the mouth into tower by neutralizer at the bottom of extracting Tata, and upwards flows by light phase distributor, with described extractant counter current contacting, extracts;

   When extracting, the interphase impurity that produces is assembled, and the interphase impurity that makes gathering with the tower that moves up into extraction tower tower body bottom under the described extractant at the bottom of expanding reach.
10. 10. the method that extracts orthene from neutralizer as claimed in claim 9 is characterized in that, and is described when extracting, and the interphase impurity that produces assembled comprise:

    When extracting, with light interphase impurity collector between the distributor mutually interphase impurity is assembled by the bottom that is located at described packing section.
11. 11. the method that extracts orthene from neutralizer as claimed in claim 9 is characterized in that,

    The described interphase impurity of gathering that makes comprises with the expanding reach that moves up into extraction tower tower body bottom under the described extractant afterwards:

    Described interphase impurity is being stored up in the expanding reach at the bottom of the described tower, and after storing up certain thickness, discharge.
12. 12. the method that extracts orthene from neutralizer as claimed in claim 11 is characterized in that, discharges described interphase impurity stores up certain thickness in expanding reach at the bottom of the described tower after to comprise:

    Open the valve of interphase impurity discharge line, discharge interphase impurity to the interphase impurity apparatus for temporary storage;

    Interphase impurity reclaims the extract of separating out from the bottom of described interphase impurity apparatus for temporary storage clarify a period of time in described interphase impurity apparatus for temporary storage after, from the top of described interphase impurity apparatus for temporary storage interphase impurity and raffinate is collected storage.
13. 13. the method that extracts orthene from neutralizer as claimed in claim 9 is characterized in that,

    Described extractant is a carrene, 1,2-dichloroethanes, chloroform, 1,1, two or more mixtures in 1-trichloroethanes, trichloro-ethylene or these halogenated hydrocarbons.
14. 14. the method that extracts orthene from neutralizer as claimed in claim 9 is characterized in that,

    Described extractant is 1.5～1.6: 1 with the ratio of the flow of neutralizer charging, and wherein the neutralizer flow is 2.1～3.5m ³/ h.
15. 15. the method that extracts orthene from neutralizer as claimed in claim 9 is characterized in that,

    In the described process that extracts, as continuous phase, extract as decentralized photo with described extractant with described neutralizer.

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