Purification treatment method and treatment system for waste white oil in component calcination process

Abstract

The invention discloses a purification treatment method for waste white oil in an assembly calcination process. The waste white oil is pretreated by carclazyte, and viscous impurities in the waste white oil are adsorbed. The feed liquid is transferred to a plate-and-frame filter, carclazyte and viscous impurities are used as filter cakes, the obtained pretreated waste white oil is used as filtrate, and the viscosity of the pretreated waste white oil is greatly reduced. The pretreated waste white oil is collected and then pumped into a chromatographic tower filled with a decolorizing agent for deep purification, and purified white oil is obtained. According to the method, the advantages of high solid-liquid separation efficiency of the plate-and-frame filter and good purification effect of the decolorizing tower are fully exerted, the purity and chromaticity of the purified waste white oil are greatly improved and reach the use standard of a production system, the waste white oil can be recycled, and the problem of high purification treatment difficulty of the waste white oil in the assembly calcination process is solved.

Description

Technical Field

[0001] The invention relates to the field of purification of waste white oil generated by calcining components in the production process of ultra-high molecular weight polyethylene fibers, and in particular to a purification treatment method and treatment system for waste white oil in the component calcining process. Background Art

[0002] In the process of producing ultra-high molecular weight polyethylene fibers by gel spinning-super-stretching method, white oil is used as solvent to dissolve ultra-high molecular weight polyethylene at high temperature, and functional additives (including antioxidants and surfactants) are added to form a spinning solution. The spinning solution is extruded through a component containing a spinneret, and then cooled in a cooling water tank to form a frozen gel filament. The component is mainly composed of a spinneret, a distribution plate, and a filter. Due to the high temperature in the component, there is carbide clogging, which affects the fiber-out effect, so it needs to be purified after a period of use. The component is generally purified by vacuum furnace calcination. It is vacuum calcined at a temperature of 450℃-500℃. The ultra-high molecular weight polyethylene fiber powder, white oil, and additives in the component are melted into a mixed liquid, and the component can be cleaned. The material after vacuum calcination is then pressed to produce waste white oil. The waste white oil produced in this section is dark brown and viscous, with poor fluidity, and is difficult to purify and cannot be reused in the production system.

[0003] The main methods for purifying waste white oil are physical adsorption and hydrorefining. The physical adsorption method generally uses activated white clay, silica gel decolorizing sand, activated carbon, and attapulgite clay to decolorize white oil. The hydrorefining method is to reduce the oxidized coloring substances in the white oil by hydrogenation, so that the color of the white oil can be restored. Hydrorefining requires an efficient hydrogenation catalyst. The dark brown viscous waste white oil will cause poisoning and deactivation of the hydrogenation catalyst. In addition, under high-temperature calcination, white oil, ultra-high molecular weight polyethylene fiber, and additives undergo complex chemical reactions. The impurity components in the waste white oil produced by component calcination are complex, and it is difficult to find one or several chemical reaction methods to remove them. Therefore, it is not suitable for hydrorefining or chemical treatment.

[0004] The conventional physical adsorption method is more about decolorizing and refining the white oil extracted from the jelly silk. This white oil is generally light yellow, has good fluidity and is easy to purify.

[0005] Li Yang in the patent ( Patent CN113981570A: A white oil in the production process of ultra-high molecular weight polyethylene fiber Recycling methods ) reported a method for recovering white oil in the production process of ultra-high molecular weight polyethylene fibers. The white oil processed in this application is conventional yellowed white oil, that is, white oil that is decomposed or yellowed due to contact with oxygen in the dissolution and spinning stages, and the waste white oil generated by high-temperature calcination of components is not involved. Summary of the invention

[0006] The object of the present invention is to provide a purification method and treatment system for waste white oil in the component calcination process, which is specifically achieved by the following technical solutions: A method for purifying waste white oil during component calcination comprises the following steps: 1) adding kaolin to the waste white oil at a temperature of 80°C to 90°C to pretreat the waste white oil, wherein the amount of kaolin added is 0.5% to 2% of the mass of the waste white oil, the mixture is stirred evenly, and the pretreatment time is 1h to 1.5h, wherein the kaolin absorbs viscous impurities in the waste white oil to form a mixed liquid; 2) transferring the liquid in step 1) to a plate-frame filter, and after filter pressing, the kaolin adsorbing the viscous impurities forms a filter cake to obtain a filtrate; 3) pumping the filtrate obtained in step 2) into a waste white oil chromatography tower filled with a decolorizer to purify the waste white oil by chromatography, wherein the chromaticity of the purified white oil is increased from almost opaque to more than 80%, the purity reaches 99.98%, and the kinematic viscosity reaches 75mm 2 / s -80mm 2 / s, meeting the quality requirements for use in production systems.

[0007] The purification method of the component calcined waste white oil, the pre-treated white oil is filtered by a plate and frame filtering method, the liquid is filtered while hot, the white clay and the adsorbed high-viscosity impurities are used as filter cakes, and the pre-treated waste white oil is used as filtrate, which is collected for subsequent deep purification.

[0008] In the purification treatment method of component calcined waste white oil, the chromatography tower is equipped with an adsorbent, which includes silica gel decolorizing sand and activated carbon, preferably silica gel decolorizing sand.

[0009] In the purification treatment method of component calcined waste white oil, the temperature of the chromatography tower is the temperature of the hot white oil filtered by the plate and frame, which is generally maintained at 70°C-85°C.

[0010] In the purification treatment method of component calcined waste white oil, the chromatography tower is operated under negative pressure to improve the purification efficiency, and the vacuum degree ranges from -0.06MPa to -0.09MPa.

[0011] A system for purifying waste white oil during component calcination comprises a container for uniformly mixing waste white oil with white clay, so that the white clay absorbs viscous impurities in the waste white oil to obtain pretreated liquid feed; a filter press device connected to the container through a pipeline to filter the liquid feed to obtain a filter cake and a filtrate to be treated, and the filtrate enters a buffer box; a chromatography tower connected to the buffer box through a pipeline with a liquid pump, and the filtrate in the buffer box enters the chromatography tower for chromatography purification to obtain reusable white oil.

[0012] The system for purifying waste white oil during the component calcination process is further designed in that the container is a pretreatment kettle having a jacket for heating.

[0013] The purification system for waste white oil during the component calcination process is further designed in that the chromatography tower is connected to a vacuum pump for extracting air to form negative pressure.

[0014] The system for purifying waste white oil during the component calcination process is further designed in that the chromatography tower is filled with an adsorbent.

[0015] The present invention first pre-treats the waste white oil generated during the component calcination process. In view of the physical property of the high viscosity of the component calcined white oil, in order to ensure the subsequent purification efficiency, the waste white oil is pre-treated. The waste white oil is preliminarily purified by using white clay, and then filtered through a plate and frame filter to further intercept viscous impurities, obtain clarified white oil with good fluidity, and collect it in a waste white oil collection tank for standby use. Then, it is transferred to a waste white oil chromatography tower equipped with an adsorbent through a liquid pump, and the waste white oil is further purified using the chromatography principle. The adsorbent has different adsorption capacities for impurities in the waste white oil, and migrates downward at different speeds. The colored impurities are easily adsorbed by the adsorbent, and then nearly colorless and transparent white oil is obtained. The chromatography tower is operated under vacuum conditions to improve the purification efficiency. The waste white oil purification effect of this process is good, and the content of the purified white oil product can reach more than 99.98%, the chromaticity can reach more than 80%, and the kinematic viscosity can reach 75mm 2 / s -80mm 2 / s, the quality meets the needs of the production system and the recycling of white oil is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the waste white oil purification system during the component calcination process. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with embodiments, but the scope of the present invention is not limited to these embodiments.

[0018] like Figure 1 The system for purifying waste white oil during the calcination process of a component shown in the figure comprises a container 1, which is used to evenly mix the waste white oil and white clay, so that the white clay absorbs viscous impurities in the waste white oil to obtain a pretreated liquid feed; a filter press device 2, which is connected to the container through a pipeline, and performs filter presses on the liquid feed to obtain a filter cake and a filtrate to be treated, and the filtrate enters a cache box 3; a chromatography tower 4, which is connected to the cache box through a pipeline with a liquid pump, and the filtrate in the cache box enters the chromatography tower for chromatography purification to obtain reusable white oil.

[0019] The container is a pretreatment kettle, which has a jacket 11 for heating. The chromatography tower is connected to a vacuum pump 5 for extracting air to form negative pressure. The chromatography tower is filled with an adsorbent 41.

[0020] The following is an example of using the above purification system to purify and recycle waste white oil during the component calcination process: Example

[0021] Add 3t of waste white oil and 15kg of white clay to the waste white oil pretreatment kettle, heat to 85°C under stirring conditions, maintain stirring for 1h, transfer the material to the plate and frame filter, and collect the filtrate in the waste white oil collection tank. Turn on the waste white oil transfer pump, and transfer the pretreated waste white oil to the waste white oil chromatography tower at a feed rate of 200kg / h. The operating pressure of the chromatography tower is -0.08MPa. The purified white oil is sampled and analyzed, and the chromaticity is 85% (in terms of transmittance), the content is 99.98%, and the kinematic viscosity is 77.89 mm 2 / s, reaching the standard for use in production systems. Example

[0022] Add 3t of waste white oil and 30kg of white clay to the waste white oil pretreatment kettle, heat to 90°C under stirring conditions, maintain stirring for 1.5h, transfer the material to the plate and frame filter, and collect the filtrate in the waste white oil collection tank. Turn on the waste white oil transfer pump, and transfer the pretreated waste white oil to the waste white oil chromatography tower at a feed rate of 200kg / h. The operating pressure of the chromatography tower is -0.085MPa. The purified white oil is sampled and analyzed, with a chromaticity of 82% (in terms of transmittance), a content of 99.98%, and a kinematic viscosity of 78.17mm. 2 / s, reaching the standard for use in production systems.

Claims

1. A method for purifying waste white oil during component calcination, characterized in that The following steps are involved: 1) Adding white clay to the waste white oil at a temperature of 80°C-90°C to pretreat the waste white oil, wherein the amount of white clay added is 0.5%-2% of the mass of the waste white oil, stirring is uniform, and the pretreatment time is 1h-1.5h. The white clay absorbs the viscous impurities in the waste white oil to form a mixed liquid; 2) The liquid in step 1) is transferred to a plate and frame filter, and after filter pressing, the white clay adsorbed with viscous impurities forms a filter cake to obtain a filtrate; 3) The filtrate obtained in step 2) is pumped into a waste white oil chromatography tower filled with a decolorizer to purify the waste white oil by chromatography. The chromaticity of the purified white oil is increased from almost opaque to more than 80%, the purity reaches 99.98%, and the kinematic viscosity reaches 75mm 2 / s -80mm 2 / s, meeting the quality requirements for use in production systems.

2. The method for purifying waste white oil from component calcination according to claim 1, characterized in that The pretreated white oil is filtered by plate and frame filtration, the feed liquid is filtered while hot, the white clay and the adsorbed high-viscosity impurities are used as filter cakes, and the pretreated waste white oil is used as filtrate, which is collected for subsequent deep purification.

3. The method for purifying waste white oil from component calcination according to claim 1, characterized in that The chromatography tower is filled with an adsorbent, which includes silica gel decolorizing sand and activated carbon, preferably silica gel decolorizing sand.

4. The method for purifying waste white oil from component calcination according to claim 3, characterized in that The temperature of the chromatography tower is 70°C-85°C.

5. The method for purifying waste white oil from component calcination according to claim 3, characterized in that The chromatography tower is operated under negative pressure to improve purification efficiency, and the vacuum degree ranges from -0.06MPa to -0.09MPa.

6. A system for purifying waste white oil during component calcination, characterized in that The invention comprises a container for uniformly mixing waste white oil and white clay, so that the white clay absorbs viscous impurities in the waste white oil to obtain a pretreated liquid feed; a filter press device connected to the container through a pipeline to filter the liquid feed to obtain a filter cake and a filtrate to be treated, and the filtrate enters a buffer box; and a chromatography tower connected to the buffer box through a pipeline with a liquid pump, and the filtrate in the buffer box enters the chromatography tower for chromatography purification to obtain reusable white oil.

7. A system for purifying waste white oil in a component calcination process according to claim 6, characterized in that: The container is a pretreatment kettle having a jacket for heating.

8. The system for purifying waste white oil in the component calcination process according to claim 6, characterized in that: The chromatography tower is connected to a vacuum pump for extracting air to form negative pressure.

9. The system for purifying waste white oil in the component calcination process according to claim 6, characterized in that: The chromatography tower is filled with an adsorbent.

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