A method and system for decolorizing crude styrene

Abstract

The application belongs to the field of chemical industry and discloses a crude styrene decolorization method and system. The system comprises an acid washing unit, an alkali washing unit, a water washing unit, a decolorizing agent regeneration unit, a salt recovery unit and a styrene refining tower; the acid washing unit comprises a first mixing device and a first separation device; the alkali washing unit comprises a second mixing device and a second separation device; the water washing unit comprises a third mixing device and a third separation device; the decolorizing agent regeneration unit comprises a refining tower and optionally a light component removal tower; and the salt recovery unit comprises a hydrocarbon recovery tower, a dryer and a condenser. The method and system can realize zero discharge of salt-containing wastewater in the crude styrene decolorization process, save decolorizing agents, alkali and water, and recover styrene and salt.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering, and more specifically, relates to a method and system for decolorizing crude styrene. Background Technology

[0002] In existing crude styrene decolorization units, inorganic acid decolorization devices are used, and acid washing, alkali washing, and water washing processes are employed. The saline wastewater generated in this process is difficult to treat, causing great trouble to the operation of the unit.

[0003] US3763015 discloses a method for separating styrene from cracked gasoline. In this method, the cracked gasoline is first distilled to recover a fraction with a boiling point between 120°C and 160°C. This fraction is then extractively distilled with an organic polar solvent containing a nitrite polymerization inhibitor that dissolves styrene. The solvent is removed, and the styrene-containing fraction is treated with nitric acid, followed by washing with water or an alkali. The resulting product is fractionated to recover substantially colorless, high-purity styrene.

[0004] As can be seen from the existing technologies, the current methods for decolorizing crude styrene only involve acid washing, alkali washing, and water washing, and do not provide an effective treatment method for the wastewater generated during the decolorization process. Therefore, there is an urgent need to propose a new method and system for decolorizing crude styrene to solve the problem of nitric acid decolorization wastewater treatment and achieve zero discharge of decolorization wastewater. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method and system for decolorizing crude styrene. Applying the method and system of this invention to the crude styrene decolorization process can achieve zero discharge of saline wastewater, save decolorizing agents, alkali solutions, and water, and recover styrene and salt.

[0006] To achieve the above objectives, the present invention provides a crude styrene decolorization system, which includes an acid washing unit, an alkaline washing unit, a water washing unit, a decolorizing agent regeneration unit, a salt recovery unit, and a styrene refining tower.

[0007] The acid washing unit includes a first mixing device and a first separation device; the alkaline washing unit includes a second mixing device and a second separation device; the water washing unit includes a third mixing device and a third separation device; the decolorizing agent regeneration unit includes a refining tower, and optionally includes a light-drying agent removal tower; the salt recovery unit includes a hydrocarbon recovery tower, a dryer, and a condenser.

[0008] The first mixing device, the first separating device, the second mixing device, the second separating device, the third mixing device, the third separating device, and the styrene refining tower are connected in sequence;

[0009] The first separation device is provided with a waste decolorizing agent outlet, which is connected to the inlet of the refining tower; optionally, the waste decolorizing agent outlet is connected in sequence to the light-removal tower and the refining tower;

[0010] The refining tower is provided with a first recycled water outlet and a regenerated decolorizing agent outlet, and the second mixing device is provided with a first recycled water inlet, the first recycled water outlet being connected to the first recycled water inlet; optionally, the light-weight removal tower is provided with a first recycled styrene outlet, and the second mixing device is also provided with a first recycled styrene inlet, the first recycled styrene outlet being connected to the first recycled styrene inlet; the first mixing device is provided with a regenerated decolorizing agent inlet, the regenerated decolorizing agent inlet being connected to the regenerated decolorizing agent outlet;

[0011] The second separation device is provided with a waste alkali solution outlet, and the third separation device is provided with a waste brine outlet. Both the waste alkali solution outlet and the waste brine outlet are connected to the inlet of the hydrocarbon recovery tower.

[0012] The hydrocarbon recovery tower is provided with a top outlet and a bottom outlet, and the bottom outlet is connected in sequence to the dryer and the condenser; the third separation device is provided with a second styrene recovery inlet and a second styrene recovery inlet, and the top outlet and the outlet of the condenser are respectively connected to the second styrene recovery inlet and the second styrene recovery inlet.

[0013] According to the present invention, preferably, the first mixing device is further provided with a crude styrene inlet and a decolorizing agent inlet.

[0014] According to the present invention, preferably, the second mixing device is further provided with an alkali inlet.

[0015] According to the present invention, preferably, the dryer is further provided with a nitrate product outlet.

[0016] According to the present invention, preferably, the styrene refining tower is further provided with a styrene product outlet.

[0017] According to the present invention, preferably, the number of theoretical plates in the refining column is 3 to 20.

[0018] According to the present invention, preferably, the theoretical number of plates in the light-light removal tower is 2 to 10.

[0019] According to the present invention, preferably, the number of theoretical plates in the hydrocarbon recovery tower is 2 to 10.

[0020] According to the present invention, preferably, the number of theoretical plates in the styrene refining column is 10 to 40.

[0021] According to the present invention, preferably, the first mixing device is an acid washing static mixer or an acid washing agitator, and the first separation device is an acid washing separation tank or an acid washing centrifuge.

[0022] According to the present invention, preferably, the second mixing device is an alkaline washing static mixer or an alkaline washing agitator, and the second separation device is an alkaline washing separation tank or an alkaline washing centrifugal separator.

[0023] According to the present invention, preferably, the third mixing device is a water washing static mixer or a water washing agitator, and the third separation device is a water washing separation tank or a water washing centrifuge.

[0024] Another aspect of the present invention provides a method for decolorizing crude styrene, which utilizes the aforementioned crude styrene decolorization system and includes the following steps:

[0025] S1: Crude styrene is sequentially subjected to acid washing, alkali washing and water washing to obtain decolorized styrene, wastewater containing decolorizing agent, waste alkali solution and saline wastewater;

[0026] S2: The wastewater containing the decolorizing agent is subjected to decolorizing agent regeneration treatment to obtain hydrocarbons, water and regenerated decolorizing agent;

[0027] S3: The waste alkaline solution and saline wastewater are subjected to salt recovery treatment to obtain hydrocarbons, water and recovered salt.

[0028] According to the present invention, preferably, the crude styrene comes from the styrene extraction unit of a styrene extraction apparatus.

[0029] According to the present invention, preferably, the decolorizing agent used in the pickling treatment is 50-80% wt nitric acid.

[0030] According to the present invention, preferably, the alkaline solution used in the alkaline washing treatment is sodium hydroxide and / or potassium hydroxide.

[0031] According to the present invention, preferably, the hydrocarbon obtained in steps S2 and S3 is styrene.

[0032] According to the present invention, preferably, the regenerating decolorizing agent is 50-80% wt nitric acid.

[0033] According to the present invention, preferably, the recovered salt is a nitrate.

[0034] According to the present invention, preferably, when the decolorizing agent regeneration unit only includes a refining tower, the top pressure of the refining tower is 5-60 kPaA and the mass reflux ratio is 0.1-5.

[0035] According to the present invention, preferably, when the decolorizing agent regeneration unit includes a light-removal tower and a refining tower, the top pressure of the light-removal tower is 5-60 kPaA and the mass reflux ratio is 0.1-5, and the top pressure of the refining tower is 50-120 kPaA and the mass reflux ratio is 0.1-5.

[0036] According to the present invention, preferably, the top pressure of the hydrocarbon recovery tower is 5-60 kPaA and the mass reflux ratio is 0-5.

[0037] According to the present invention, preferably, the operating pressure of the dryer is 5 to 120 kPaA.

[0038] According to the present invention, preferably, the outlet temperature of the condenser is 10–60°C.

[0039] According to the present invention, preferably, the top pressure of the styrene refining tower is 5-15 kPaA, and the mass reflux ratio is 1-3.

[0040] According to the present invention, preferably, the operating temperature of the pickling agitator is 20-60°C, the residence time is 5-120 seconds, and the stirring rate is 100-1000 r / min; the residence time of the pickling centrifuge is 5-30 min, and the rotation speed is 1000-15000 r / min.

[0041] According to the present invention, preferably, the operating temperature of the alkaline washing agitator is 20-60°C, the residence time is 5-120 seconds, and the stirring rate is 100-1000 r / min; the residence time of the alkaline washing centrifuge is 5-30 min, and the rotation speed is 1000-15000 r / min.

[0042] According to the present invention, preferably, the operating temperature of the water washing agitator is 20-60°C, the residence time is 5-120 seconds, and the stirring rate is 100-1000 r / min; the residence time of the water washing centrifuge is 5-30 min, and the rotation speed is 1000-15000 r / min.

[0043] The beneficial effects of the technical solution of the present invention are as follows:

[0044] Applying the method and system of this invention to the crude styrene decolorization process can achieve zero discharge of saline wastewater in the crude styrene decolorization process, and save decolorizing agent, alkali solution, and water, while recovering styrene and salt.

[0045] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0046] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0047] Figure 1 A schematic diagram of a crude styrene decolorization system provided in Embodiment 1 of the present invention is shown.

[0048] Figure 2 A schematic diagram of a crude styrene decolorization system provided as a comparative example is shown.

[0049] The annotations in the attached figures are explained as follows:

[0050] 1-Crude styrene inlet; 2-Decolorizing agent inlet; 3-Alkali inlet; 4-Styrene-containing material transport pipeline; 5-First mixing equipment; 6-First separation equipment; 7-Second mixing equipment; 8-Second separation equipment; 9-Third mixing equipment; 10-Third separation equipment; 11-Light styrene removal tower; 12-Refining tower; 13-Hydrocarbon recovery tower; 14-Dryer; 15-Condenser; 16-Regenerated decolorizing agent pipeline; 17-First recovered styrene pipeline; 18-First recovered water pipeline; 19-Nitrate product outlet; 20-Waste decolorizing agent outlet; 21-Waste alkali outlet; 22-Waste brine outlet; 23-Desalinated water inlet; 24-Acid washing styrene transport pipeline; 25-Alkali washing styrene transport pipeline; 26-Styrene refining tower; 27-Styrene product outlet; 28-Second recovered styrene pipeline; 29-Second recovered water pipeline. Detailed Implementation

[0051] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0052] The following examples illustrate the present invention in detail.

[0053] Example 1

[0054] This embodiment provides a crude styrene decolorization system, such as Figure 1 As shown, the system includes an acid washing unit, an alkaline washing unit, a water washing unit, a decolorizing agent regeneration unit, a salt recovery unit, and a styrene refining tower;

[0055] The acid washing unit includes a first mixing device 5 and a first separation device 6; the alkaline washing unit includes a second mixing device 7 and a second separation device 8; the water washing unit includes a third mixing device 9 and a third separation device 10; the decolorizing agent regeneration unit includes a refining tower 12 and a light-light-removal tower 11; the salt recovery unit includes a hydrocarbon recovery tower 13, a dryer 14, and a condenser 15.

[0056] The first mixing device 5, the first separation device 6, the acid-washed styrene conveying pipeline 24, the second mixing device 7, the second separation device 8, the alkali-washed styrene conveying pipeline 25, the third mixing device 9, the third separation device 10, the styrene-containing material conveying pipeline 4, and the styrene refining tower 26 are connected in sequence.

[0057] The first separation device 6 is provided with a waste decolorizing agent outlet 20, which is connected in sequence to the light-light removal tower 11 and the refining tower 12;

[0058] The refining tower 12 is provided with a first recycled water outlet and a regenerated decolorizing agent outlet; the second mixing device 7 is provided with a first recycled water inlet; the first recycled water outlet and the first recycled water inlet are connected through a first recycled water pipeline 18; the light-duty removal tower 11 is provided with a first recycled styrene outlet; the second mixing device 7 is also provided with a first recycled styrene inlet; the first recycled styrene outlet and the first recycled styrene inlet are connected through a first recycled styrene pipeline 17; the first mixing device 5 is provided with a regenerated decolorizing agent inlet; the regenerated decolorizing agent inlet and the regenerated decolorizing agent outlet are connected through a regenerated decolorizing agent pipeline 16.

[0059] The second separation device 8 is provided with a waste alkali outlet 21, and the third separation device 10 is provided with a waste brine outlet 22. Both the waste alkali outlet 21 and the waste brine outlet 22 are connected to the inlet of the hydrocarbon recovery tower 13.

[0060] The hydrocarbon recovery tower 13 is provided with a top outlet and a bottom outlet, and the bottom outlet is connected in sequence to the dryer 14 and the condenser 15; the third separation device 9 is provided with a second styrene recovery inlet and a second styrene recovery inlet, and the top outlet 31 and the outlet of the condenser 15 are respectively connected to the second styrene recovery inlet and the second styrene recovery inlet through the second styrene recovery pipeline 28 and the second styrene recovery pipeline 29.

[0061] The first mixing device 5 is also provided with a crude styrene inlet 1 and a decolorizing agent inlet 2;

[0062] The second mixing device 7 is also provided with an alkali inlet 3;

[0063] The dryer 14 is also provided with a nitrate product outlet 19;

[0064] The styrene refining tower 26 is also equipped with a styrene product outlet 27.

[0065] The refining column has 10 theoretical plates; the light-weight removal column has 6 theoretical plates.

[0066] The hydrocarbon recovery tower has a theoretical number of 6 plates;

[0067] The theoretical number of plates in the styrene refining column is 30;

[0068] The first mixing device is an acid washing agitator, and the first separation device is an acid washing centrifuge; the second mixing device is an alkaline washing agitator, and the second separation device is an alkaline washing centrifuge; the third mixing device is a water washing agitator, and the third separation device is a water washing centrifuge.

[0069] The method for decolorizing crude styrene from the styrene extraction unit of a styrene extraction apparatus using the crude styrene decolorization system described in this embodiment includes the following steps:

[0070] S1: Crude styrene is sequentially subjected to acid washing, alkali washing, and water washing to obtain decolorized styrene, wastewater containing decolorizing agent, waste alkali solution, and saline wastewater; the decolorizing agent used in the acid washing treatment is 70% wt nitric acid; the alkali solution used in the alkali washing treatment is 20% wt sodium hydroxide.

[0071] S2: The wastewater containing the decolorizing agent is subjected to decolorizing agent regeneration treatment to obtain hydrocarbons, water, and regenerated decolorizing agent; the regenerated decolorizing agent is 50-80% wt nitric acid;

[0072] S3: The waste alkaline solution and saline wastewater are subjected to salt recovery treatment to obtain hydrocarbons, water, and recovered salt. The recovered salt is nitrate. The hydrocarbon obtained in steps S2 and S3 is styrene.

[0073] The pressure at the top of the light-light removal tower is 5 kPaA, and the mass reflux ratio is 1. The pressure at the top of the refining tower is 100 kPaA, and the mass reflux ratio is 1.

[0074] The hydrocarbon recovery tower has a top pressure of 5 kPaA and a mass reflux ratio of 1; the dryer has an operating pressure of 5 kPaA; and the condenser has an outlet temperature of 40°C.

[0075] The pressure at the top of the styrene refining tower is 10 kPaA, and the mass reflux ratio is 2.

[0076] The pickling agitator operates at a temperature of 40°C, a residence time of 60 seconds, and a stirring rate of 500 r / min; the pickling centrifuge has a residence time of 20 minutes and a rotation speed of 10,000 r / min.

[0077] The alkaline washing agitator operates at a temperature of 40°C, a residence time of 50 seconds, and a stirring rate of 500 r / min; the alkaline washing centrifuge operates at a residence time of 20 minutes and a rotation speed of 10,000 r / min.

[0078] The operating temperature of the water washing agitator is 40℃, the residence time is 45 seconds, and the stirring rate is 500 r / min; the residence time of the water washing centrifuge is 20 min, and the rotation speed is 10000 r / min.

[0079] Comparative Example

[0080] This comparative example provides an existing crude styrene decolorization system, such as Figure 2 As shown, the system includes an acid washing unit, an alkaline washing unit, a water washing unit, and a styrene refining tower;

[0081] The acid washing unit includes a first mixing device 5 and a first separation device 6; the alkaline washing unit includes a second mixing device 7 and a second separation device 8; the water washing unit includes a third mixing device 9 and a third separation device 10.

[0082] The first mixing device 5, the first separation device 6, the acid-washed styrene conveying pipeline 24, the second mixing device 7, the second separation device 8, the alkali-washed styrene conveying pipeline 25, the third mixing device 9, the third separation device 10, the styrene-containing material conveying pipeline 4, and the styrene refining tower 26 are connected in sequence.

[0083] The first mixing device 5 is provided with a crude styrene inlet 1 and a decolorizing agent inlet 2; the first separation device 6 is provided with a waste decolorizing agent outlet 20;

[0084] The second mixing device 7 is provided with an alkali inlet 3; the second separation device 8 is provided with a waste alkali outlet 21;

[0085] The third separation device 9 is provided with a demineralized water inlet 23; the third separation device 10 is provided with a waste brine outlet 22;

[0086] The styrene refining tower 26 is equipped with a styrene product outlet 27.

[0087] The theoretical number of plates in the styrene refining tower is 30.

[0088] The first mixing device is an acid washing static mixer, and the first separation device is an acid washing separation tank; the second mixing device is an alkaline washing static mixer, and the second separation device is an alkaline washing separation tank; the third mixing device is a water washing static mixer, and the third separation device is a water washing separation tank.

[0089] The method for decolorizing crude styrene from the styrene extraction unit of a styrene extraction apparatus using the crude styrene decolorization system described in this comparative example includes:

[0090] Deionized water is added to the third mixing device 9 through the deionized water inlet 23; crude styrene is sequentially subjected to acid washing, alkali washing and water washing to obtain decolorized styrene, wastewater containing decolorizing agent, waste alkali solution and saline wastewater;

[0091] The decolorized styrene is discharged from the styrene product outlet 27 via the styrene refining tower; the wastewater containing decolorizing agent is discharged from the waste decolorizing agent outlet 20; the waste alkali solution is discharged from the waste alkali solution outlet 21; and the saline wastewater is discharged from the waste brine outlet.

[0092] The decolorizing agent used in the acid washing treatment is 70% wt nitric acid; the alkaline solution used in the alkaline washing treatment is 20% wt sodium hydroxide.

[0093] The pressure at the top of the styrene refining tower is 10 kPaA, and the mass reflux ratio is 2.

[0094] The operating temperature of the pickling static mixer is 40°C, and the residence time is 60 seconds; the residence time of the pickling separation tank is 2 hours.

[0095] The operating temperature of the alkaline washing static mixer is 40℃, and the residence time is 60 seconds; the residence time of the alkaline washing separation tank is 2 hours.

[0096] The operating temperature of the static water mixer is 40°C and the residence time is 60 seconds; the residence time of the water separation tank is 2 hours.

[0097] Test case

[0098] The processing results of Example 1 and the comparative example are compared as shown in Table 1:

[0099]

[0100]

[0101] As can be seen from the comparison results in Table 1, the crude styrene decolorization system provided by the present invention can achieve zero discharge of saline wastewater in the crude styrene decolorization process, and save decolorizing agent, alkali solution, and water, while recovering styrene and nitrates. After decolorization, the styrene can reach the premium grade after refining.

[0102] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for decolorizing crude styrene, characterized in that, The crude styrene decolorization system used in this method includes an acid washing unit, an alkali washing unit, a water washing unit, a decolorizing agent regeneration unit, a salt recovery unit, and a styrene refining tower; The acid washing unit includes a first mixing device and a first separation device; the alkaline washing unit includes a second mixing device and a second separation device; the water washing unit includes a third mixing device and a third separation device; the decolorizing agent regeneration unit includes a refining tower and a light-weight removal tower; The salt recovery unit includes a hydrocarbon recovery tower, a dryer, and a condenser; The first mixing device, the first separating device, the second mixing device, the second separating device, the third mixing device, the third separating device, and the styrene refining tower are connected in sequence; The first separation device is provided with a waste decolorizing agent outlet, which is connected in sequence to the light-light removal tower and the refining tower; The refining tower is provided with a first recycled water outlet and a regenerated decolorizing agent outlet; the second mixing device is provided with a first recycled water inlet, and the first recycled water outlet is connected to the first recycled water inlet; the light-duty removal tower is provided with a first recycled styrene outlet; the second mixing device is also provided with a first recycled styrene inlet, and the first recycled styrene outlet is connected to the first recycled styrene inlet; the first mixing device is provided with a regenerated decolorizing agent inlet, and the regenerated decolorizing agent inlet is connected to the regenerated decolorizing agent outlet; The second separation device is provided with a waste alkali solution outlet, and the third separation device is provided with a waste brine outlet. Both the waste alkali solution outlet and the waste brine outlet are connected to the inlet of the hydrocarbon recovery tower. The hydrocarbon recovery tower is provided with a top outlet and a bottom outlet, and the bottom outlet is connected in sequence to the dryer and the condenser; the third mixing device is provided with a second styrene recovery inlet and a second styrene recovery inlet, and the top outlet and the outlet of the condenser are respectively connected to the second styrene recovery inlet and the second styrene recovery inlet; The method includes the following steps: S1: Crude styrene is sequentially subjected to acid washing, alkali washing and water washing to obtain decolorized styrene, wastewater containing decolorizing agent, waste alkali solution and saline wastewater; S2: The wastewater containing the decolorizing agent is subjected to decolorizing agent regeneration treatment to obtain hydrocarbons, water and regenerated decolorizing agent; S3: The waste alkaline solution and saline wastewater are subjected to salt recovery treatment to obtain hydrocarbons, water and recovered salt; The hydrocarbon obtained in steps S2 and S3 is styrene; The pressure at the top of the light-light removal column is 5~60 kPaA, and the mass reflux ratio is 0.1~5. The pressure at the top of the refining column is 50~120 kPaA, and the mass reflux ratio is 0.1~5. The pressure at the top of the hydrocarbon recovery tower is 5~60 kPaA, and the mass reflux ratio is 1~5. The operating pressure of the dryer is 5~120 kPaA; The outlet temperature of the condenser is 10~60℃; The decolorizing agent used in the pickling process is 50-80% wt nitric acid.

2. The method for decolorizing crude styrene according to claim 1, wherein, The first mixing device is also provided with a crude styrene inlet and a decolorizing agent inlet; The second mixing device is also equipped with an alkali inlet; The dryer is also equipped with a nitrate product outlet; The styrene refining tower is also equipped with a styrene product outlet.

3. The method for decolorizing crude styrene according to claim 1, wherein, The theoretical number of plates in the refining column is 3 to 20; The theoretical number of plates in the light-light removal tower is 2 to 10; The theoretical number of trays in the hydrocarbon recovery tower is 2 to 10; The theoretical number of plates in the styrene refining column is 10 to 40. The first mixing device is an acid washing static mixer or an acid washing agitator, and the first separation device is an acid washing separation tank or an acid washing centrifugal separator; The second mixing device is an alkaline washing static mixer or an alkaline washing agitator, and the second separation device is an alkaline washing separation tank or an alkaline washing centrifugal separator; The third mixing device is a water washing static mixer or a water washing agitator, and the third separation device is a water washing separation tank or a water washing centrifugal separator.

4. The method for decolorizing crude styrene according to claim 1, wherein, The crude styrene comes from the styrene extraction unit of the styrene extraction apparatus.

5. The method for decolorizing crude styrene according to claim 1, wherein, The alkaline solution used in the alkaline washing treatment is sodium hydroxide and / or potassium hydroxide; The regenerating decolorizing agent is 50-80% wt nitric acid; The recovered salt is nitrate.

6. The method for decolorizing crude styrene according to claim 1, wherein, The pressure at the top of the styrene refining tower is 5-15 kPaA, and the mass reflux ratio is 1-3.

7. The method for decolorizing crude styrene according to claim 3, wherein, The operating temperature of the pickling agitator is 20~60℃, the residence time is 5~120sec, and the stirring rate is 100~1000r / min; the residence time of the pickling centrifuge is 5~30min, and the rotation speed is 1000~15000r / min. The alkaline washing agitator operates at a temperature of 20-60℃, a residence time of 5-120 seconds, and a stirring rate of 100-1000 r / min; the alkaline washing centrifuge operates at a residence time of 5-30 minutes and a rotation speed of 1000-15000 r / min. The operating temperature of the water washing agitator is 20~60℃, the residence time is 5~120sec, and the stirring rate is 100~1000r / min; the residence time of the water washing centrifuge is 5~30min, and the rotation speed is 1000~15000r / min.

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