System and method for extracting montan wax from pulverized coal

文档序号：163715 发布日期：2021-10-29 浏览：46次中文

阅读说明：本技术 用于粉煤提取褐煤蜡的系统及方法 (System and method for extracting montan wax from pulverized coal ) 是由崔鑫张中华常彬杰张翠清郭屹于 2020-04-29 设计创作，主要内容包括：本发明提供了一种用于粉煤提取褐煤蜡的系统及方法。本发明提供的用于粉煤提取褐煤蜡的系统包括依次连接的制浆单元,萃取单元,过滤单元和脱溶单元,其中所述萃取单元包括管式萃取器。本发明提供的粉煤提取褐煤蜡的方法,所述方法包括：将粉煤原料与萃取剂混合,得到料浆；将所述料浆经管式萃取器进行萃取,得到萃取后的料浆；将所述萃取后的料浆进行过滤,得到滤饼和滤液a；将所述滤液a进行蒸馏,得到褐煤蜡。本发明提供的方法能够实现粉煤萃取褐煤蜡,萃取率高,溶剂损失率低。(The invention provides a system and a method for extracting montan wax from pulverized coal. The system for extracting montan wax from pulverized coal comprises a pulping unit, an extraction unit, a filtering unit and a desolventizing unit which are sequentially connected, wherein the extraction unit comprises a tubular extractor. The invention provides a method for extracting montan wax from pulverized coal, which comprises the following steps: mixing a pulverized coal raw material with an extracting agent to obtain slurry; extracting the slurry by a tubular extractor to obtain extracted slurry; filtering the extracted slurry to obtain a filter cake and a filtrate a; and distilling the filtrate a to obtain the montan wax. The method provided by the invention can realize the extraction of the montan wax by the pulverized coal, and has high extraction rate and low solvent loss rate.)

1. A system for extracting montan wax from pulverized coal comprises a pulping unit, an extraction unit, a filtering unit and a desolventizing unit which are sequentially connected, wherein the extraction unit comprises a tubular extractor.

2. The system of claim 1, wherein the pulping unit comprises a vibrating screen, a pulping tank and a coal slurry pump which are connected in sequence; and/or the filtering unit comprises a positive pressure filter, a pull belt filter and a microporous filter which are connected in sequence; and/or the desolventizing unit comprises a desolventizing machine.

3. The system according to claim 1 or 2, wherein the tube extractor is S-shaped and comprises at least 10 single tubes, preferably the tube extractor is made of stainless steel or carbon steel; it is further preferred that the first and second liquid crystal compositions,

the inner diameter of the tubular extractor is 20-60mm, the outer diameter of the tubular extractor is 25-70mm, preferably, the inner diameter of the tubular extractor is 30-50mm, and the outer diameter of the tubular extractor is 40-60 mm; and/or the length of a single tube of the tubular extractor is 30-70m, and the total length is 1000-4000 m; preferably, the length of the single tube of the tubular extractor is 45-55m, and the total length is 1200-3600 m.

4. A method of extracting montan wax from pulverized coal, the method comprising:

step A: mixing a pulverized coal raw material with an extracting agent to obtain slurry;

and B: extracting the slurry by a tubular extractor to obtain extracted slurry;

and C: filtering the extracted slurry to obtain a filter cake and a filtrate a;

step D: distilling the filtrate a to obtain montan wax;

preferably, the method further comprises the steps of washing and filtering the filter cake obtained in the step C to obtain wax extracting coal and filtrate b, and mixing the filtrate a and the filtrate b and then distilling.

5. The method of claim 4,

the tubular extractor is S-shaped and comprises at least 10 single tubes, and preferably, the tubular extractor is made of stainless steel or carbon steel; it is further preferred that the first and second liquid crystal compositions,

6. A method according to claim 4 or 5, characterized in that in step A, the particle size of the pulverized coal feed is <1mm, and/or the ratio of the mass of the pulverized coal feed to the volume of the extractant is 1:1-1:5(kg: L), preferably 1:1.5-1:2(kg: L); and/or the extractant is selected from C2-C10 ester compounds and C1-C10 alcohol compounds, preferably at least one selected from ethyl formate, ethyl acetate, ethanol and propanol; and/or the slurry has a solids content of 30-50%, preferably 33-40%; and/or

In the step B, the extraction temperature is 70-120 ℃, and preferably 80-110 ℃; and/or the extraction time is 5-60min, preferably 10-30 min; and/or the pressure of the extraction is 0.2-2MPa, preferably 0.5-1 MPa; and/or the slurry flow rate in the tube extractor is from 1.5 to 4m/s, preferably from 2 to 2.5 m/s.

7. The method according to any one of claims 4 to 6, wherein in step C, the filtration is performed by using a three-stage filtration device, preferably, the first stage filtration is performed by using a positive pressure filter, the second stage filtration is performed by using a draw belt filter, and the third stage filtration is performed by using a microporous filter; and/or the solids content of the filtrate a is less than 0.1%.

8. The method according to any one of claims 4 to 7, characterized in that the washing is carried out with an extractant, preferably the ratio between the mass of the filter cake and the volume of the extractant is 1:1.5-1.5:1(kg: L); further preferably, the extractant is selected from C2-C10 ester compounds and/or C1-C10 alcohol compounds, preferably at least one selected from ethyl formate, ethyl acetate, ethanol and propanol; and/or the temperature of the washing is 70-110 ℃, preferably 80-100 ℃; and/or the washing time is 5 to 30 minutes.

9. The method according to any one of claims 4-8, further comprising:

carrying out desolventizing treatment on the wax extraction coal to obtain desolventized coal;

preferably, the desolventizing treatment comprises desolventizing by using a desolventizing machine and desolventizing by using a vacuum desolventizing machine.

10. The method according to any one of claims 4-9, further comprising: and recycling the solvent obtained by the distillation and/or the desolventizing treatment.

Technical Field

The invention relates to a system and a method for extracting montan wax from pulverized coal.

Background

Montan wax is an indispensable important chemical product. Montan wax, also known as montan wax, is a mineral wax containing wax, resin and bitumen. The extraction of the montan wax is that the montan wax obtained by extracting waxy lignite or peat with a solvent (benzene, gasoline and the like) is a natural mineral wax extracted from the lignite, and the wax-rich lignite is less than 1 percent of the total storage amount of the lignite, so the wax-rich coal resource is extremely precious. However, wax-rich lignite usually has the characteristics of high water content, poor mechanical strength and the like, so that a large amount of pulverized coal is generated in the processes of mining, crushing and drying, and the amount of the pulverized coal reaches more than half. The granularity required by a common montan wax extraction device is larger than 1mm, and the pulverized coal smaller than 1mm cannot be utilized, so that the resource is greatly wasted.

The traditional extraction process adopts granular coal feeding, which also causes that the complete sealing can not be realized in the process of adding lignite into the extractor, and the solvent loss rate is increased. Meanwhile, in order to ensure the extraction temperature, the extractant needs to be preheated to a higher temperature, which also causes a large amount of steam to be generated in the process of adding the extractant into the extractor, and the micro-negative pressure extractor also ensures the leakage of the extraction steam. It is difficult to achieve high temperature extraction due to the negative pressure operation.

Patent CN 101434868B-production method for extracting montan wax from lignite provides an extraction method for montan wax, which adopts 2-8mm lignite as raw material, and adopts a granulation mode for pulverized coal smaller than 2 mm. The granulation process needs a binder, and a large amount of pulverized coal is easily generated in the extraction process and the scraper conveying process, so that the operation of equipment is difficult.

Patent CN 102861455A-a powdered lignite circulating fluidization extraction montan wax device provides a new technology aiming at the extraction of pulverized coal, and 0.2mm-0.6mm pulverized coal can be used. However, in the process of screening pulverized coal, on one hand, the pulverized coal with the water content (27%) being higher is difficult to separate below 0.2mm, and on the other hand, the fine pulverized lignite is easy to cause dust explosion, so that the hidden danger in the implementation process is large.

The particle size is a key factor affecting the extraction rate for the extraction process, and generally, the smaller the particle size, the higher the extraction rate, and the particle size required by the current extraction method is about 1-15mm, which also results in the decrease of the extraction rate of the montan wax.

The problem of current montan wax extraction device:

(1) the traditional lignite extractor cannot use pulverized coal (<1mm) due to the limitation of extraction equipment (>1mm), so that more than 50% of wax-rich coal cannot be utilized.

(2) The higher the temperature, the higher the pressure and the smaller the particle size in the extraction process, the higher the extraction rate, and the traditional extraction process adopts the modes of solid particle feeding and high-temperature extractant feeding, so that the extraction process is carried out under the micro-negative pressure, which also causes the problems of low extraction temperature, small pressure, large particle size and the like, and the extraction rate is low and generally not more than 75%.

In summary, the prior art cannot realize the safe and efficient lignite extraction process of pulverized coal.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a lignite wax extraction method capable of realizing pulverized coal extraction, which adopts a tubular extractor to replace the original drag chain and tank group type extractors, and adopts a method for preparing coal slurry by using an extractant to realize the extraction of lignite wax from full-moisture lignite. The method not only realizes the utilization of the pulverized coal of the wax-rich coal, but also reduces the drying process of the lignite, and improves the extraction rate of the crude wax by more than 5 percent.

In a first aspect, the invention provides a system for extracting montan wax from pulverized coal, which comprises a pulping unit, an extraction unit, a filtering unit and a desolventizing unit which are connected in sequence, wherein the extraction unit comprises a tubular extractor.

According to some embodiments of the invention, the pulping unit comprises a vibrating screen, a pulping tank and a coal pulp pump connected in sequence.

According to some embodiments of the invention, the filtration unit comprises a positive pressure filter, a draw tape filter and a microporous filter connected in series.

According to some embodiments of the invention, the desolventizing unit comprises a desolventizing machine.

According to some embodiments of the invention, the tubular extractor is S-shaped comprising at least 10 single tubes. As shown in fig. 1.

According to some embodiments of the invention, the tubular extractor is made of stainless steel or carbon steel.

According to some embodiments of the invention, the tubular extractor has an inner diameter of 20 to 60mm and an outer diameter of 25 to 70 mm.

According to a preferred embodiment of the invention, the tubular extractor has an internal diameter of 30 to 50mm and an external diameter of 40 to 60 mm.

According to some embodiments of the present invention, the tubular extractor has a single tube length of 30-70m and a total length of 1000-4000 m.

According to the preferred embodiment of the invention, the single tube length of the tubular extractor is 45-55m, and the total length is 1200-3600 m.

According to some embodiments of the invention, the jacket of the tubular extractor is a steam heat source for heating the extraction material.

In a second aspect, the present invention provides a method for extracting montan wax from pulverized coal, which comprises:

step A: mixing a pulverized coal raw material with an extracting agent to obtain slurry;

and B: extracting the slurry by a tubular extractor to obtain extracted slurry;

and C: filtering the extracted slurry to obtain a filter cake and a filtrate a;

step D: and distilling the filtrate a to obtain the montan wax.

According to some embodiments of the invention, the tubular extractor is S-shaped comprising at least 10 single tubes. As shown in fig. 1.

According to some embodiments of the invention, the tubular extractor is made of stainless steel or carbon steel.

According to some embodiments of the invention, the tubular extractor has an inner diameter of 20 to 60mm and an outer diameter of 25 to 70 mm.

According to a preferred embodiment of the invention, the tubular extractor has an internal diameter of 30 to 50mm and an external diameter of 40 to 60 mm.

According to some embodiments of the present invention, the tubular extractor has a single tube length of 30-70m and a total length of 1000-4000 m.

According to the preferred embodiment of the invention, the single tube length of the tubular extractor is 45-55m, and the total length is 1200-3600 m.

According to some embodiments of the invention, the jacket of the tubular extractor is a steam heat source for heating the extraction material.

According to some embodiments of the invention, in step a, the particle size of the pulverized coal feed is <1 mm.

According to some embodiments of the invention, in step a, the ratio of the mass of the pulverized coal feed to the volume of the extractant is from 1:1 to 1:5(kg: L).

According to a preferred embodiment of the invention, in step A, the ratio of the mass of the pulverized coal raw material to the volume of the extractant is 1:1.5 to 1:2(kg: L).

According to some embodiments of the invention, in step a, the extractant is selected from C2-C10 esters and/or C1-C10 alcohols.

According to a preferred embodiment of the present invention, in step a, the extractant is selected from at least one of ethyl formate, ethyl acetate, ethanol and propanol.

According to some embodiments of the invention, in step a, the slurry has a solids content of 30-50%.

According to a preferred embodiment of the invention, in step a, the slurry has a solids content of 33-40%.

According to some embodiments of the invention, the temperature of the extraction in step B is 70-120 ℃.

According to a preferred embodiment of the invention, the temperature of the extraction in step B is between 80 and 110 ℃.

According to some embodiments of the invention, in step B, the time of the extraction is 5 to 60 min.

According to a preferred embodiment of the invention, in step B, the extraction time is 10-30 min.

According to some embodiments of the invention, the pressure of the extraction in step B is between 0.2 and 2 MPa.

According to a preferred embodiment of the invention, in step B, the pressure of the extraction is between 0.5 and 1 MPa.

According to some embodiments of the invention, the slurry flow rate in the pipe extractor in step B is between 1.5 and 4 m/s.

According to a preferred embodiment of the invention, in step B, the slurry flow rate in the tube extractor is between 2 and 2.5 m/s.

According to some embodiments of the invention, in step C, the filtration is performed using a three-stage filtration device.

According to the preferred embodiment of the invention, in step C, the first stage filtration adopts a positive pressure filter, the second stage filtration adopts a drawstring filter, and the third stage filtration adopts a microporous filter.

According to some embodiments of the invention, in step C, the filtrate a has a solid content of less than 0.1%.

According to some embodiments of the invention, the method further comprises washing the filter cake obtained in the step C, filtering to obtain wax extracting coal and filtrate b, and mixing the filtrate a and the filtrate b and then distilling.

According to some embodiments of the invention, the post-washing filtration is performed using a three-stage filtration device, preferably, the first stage filtration is performed using a positive pressure filter, the second stage filtration is performed using a belt filter, and the third stage filtration is performed using a microporous filter.

According to some embodiments of the invention, the washing is performed with an extractant.

According to a preferred embodiment of the invention, the ratio between the mass of the filter cake and the volume of the extractant in the washing is between 1:1.5 and 1.5:1(kg: L).

According to some embodiments of the invention, the extractant is selected from C2-C10 esters and/or C1-C10 alcohols.

According to a preferred embodiment of the present invention, the extractant is selected from at least one of ethyl formate, ethyl acetate, ethanol and propanol.

According to some embodiments of the invention, the temperature of the washing is 70-110 ℃.

According to a preferred embodiment of the invention, the temperature of the washing is between 80 and 100 ℃.

According to a preferred embodiment of the invention, the washing time is 5 to 30 minutes.

According to some embodiments of the invention, the method further comprises: and carrying out desolventizing treatment on the wax extraction coal to obtain desolventized coal.

According to some embodiments of the invention, the desolventizing treatment comprises desolventizing with a desolventizing machine and desolventizing with a vacuum desolventizing machine.

According to some embodiments of the invention, the method further comprises: and recycling the solvent obtained by the distillation and/or the desolventizing treatment.

According to some specific embodiments of the present invention, the method goes through the steps of pulping, extracting, filtering and separating, washing filter cake, desolventizing wax, and desolventizing wax-extracted coal, referring to the process flow of extracting montan wax from pulverized coal as shown in fig. 2, specifically,

firstly, mixing and stirring 1mm coal powder and an extracting agent according to the proportion (mass/volume) of 1:1.5-1:2(kg: L) to prepare slurry (the solid content is 33-40%);

pumping the prepared slurry into a tubular extractor through a slurry pump, and extracting the wax in the lignite by using a solvent. The outer wall of the reactor is provided with a steam jacket, slurry passes through the tubular extractor at the speed of 2m/s, the retention time of the slurry in the reactor is 10-30 minutes, the reaction temperature is 80-100 ℃, and the extraction pressure is 0.5-1 MPa;

and (5) filtering and separating. Introducing the extracted slurry into a three-stage filtering device, wherein the first stage is a positive pressure filter, the second stage is a pull belt type filter, and the third stage is a microporous filter, and filtering to obtain an extract a with the solid content of less than 0.1%;

washing the filtered filter cake with an 80 ℃ extracting agent in a ratio (mass/volume) of 1:1(kg: L), and carrying out positive pressure filtration, bag-pulling filtration and microporous filtration on the washed filter cake to obtain an extract liquid b and wax extraction coal;

mixing the extract a and the extract b, introducing the mixture into a distillation tower, and removing the solvent at the temperature of 130 ℃ to obtain montan wax and a circulating solvent a;

conveying the wax extraction coal to a desolventizing system, and sequentially passing through a desolventizing machine and a vacuum desolventizing machine to obtain desolventized coal and a circulating solvent b;

and mixing the circulating solvent a, the circulating solvent b and a small amount of fresh solvent, conveying the mixture to a pulping system, and continuously recycling.

The invention can realize extraction of pulverized coal, and the extraction rate of the montan wax is higher than that of the traditional crushed coal. Compared with the traditional crushed coal (1-10mm) extraction, the invention has the following advantages:

1. the lignite wax can be extracted by pulverized coal;

2. because the granularity of the extraction raw material is small, the temperature and the pressure are high, and the extraction rate is improved by 5 percent;

3. the process from extraction to liquid-solid separation is totally closed, and the solvent loss rate is 10 percent lower than that of the traditional mode.

Drawings

FIG. 1 is a schematic diagram of a tubular extractor used in an embodiment according to the present invention.

Fig. 2 shows a process flow of extracting montan wax from pulverized coal according to an embodiment of the present invention.

Detailed Description

The invention will be further described with reference to the following figures and examples, which are given by way of illustration only and are not intended to limit the scope of the invention.

Specifically, the invention provides a tubular extractor to replace the original drag chain and tank group type extractors, so as to realize pulverized coal extraction. The tubular extractor is characterized in that: the tubular extractor is S-shaped, as shown in FIG. 1, the inner diameter of the tube is 30-50mm, the outer diameter is 40-60mm, the length of a single tube is about 50m, the total length is 1200-3600m, the flow velocity of the fluid in the tube is 2-2.5m/S, and the extraction time is 10-30 minutes. The jacket is a steam heat source and is used for heating the extraction material.

In the following examples and comparative examples, the obtained resin and montan wax were subjected to composition analysis and determination in the resin and asphalt contents in accordance with GB/T2559-2005 montan wax determination method;

calculating the pure wax extraction rate: p% ═ W_{Montan wax}xω_{Pure wax, montan wax}％/(W_{Brown coal}xω_{Pure wax, brown coal}％)x100％

P represents the yield of pure wax,%

W_{Brown coal}Denotes the mass of lignite, kg

ω_{Pure wax, montan wax}Represents the wax content in the montan wax by%

W_{Montan wax}Denotes the mass of montan wax, kg

ω_{Pure wax, brown coal}Represents the wax content in lignite

Solvent loss ratio (m)³Ton wax)

Calculation of solvent loss ratio (m)³Wax (V)_in-V_out)/W_{Montan wax}

V_inDenotes the volume of extractant added, m3

V_outDenotes the volume of extractant received after extraction, m3

W_{Montan wax}Denotes the mass of montan wax, kg

Example 1

Lignite (pure wax content 4.8%) is sieved to prepare particles smaller than 1mm, 50 kg of lignite is taken, 75L of extractant ethyl acetate is added according to the mass/volume ratio of 1:1.5(kg: L) to prepare coal slurry, the coal slurry is pumped into a tubular extractor by using a coal slurry pump, and superheated steam is introduced into a jacket. Wherein the inner diameter of the tube of the tubular extractor is 30mm, the outer diameter is 50mm, the length of the single tube is about 50m, and the total length is 1200 m. The extraction temperature was 110 ℃ and the pressure 0.5MPa, and the slurry was passed through a tubular extractor at a speed of 2 m/s. After extraction for 10 minutes, the mixture enters a separator (sequentially passes through a positive pressure filter, a drawstring filter and a microporous filter) to realize liquid-solid separation, and is sequentially filtered, filter cake washing (the washing condition is that the mass/volume of the filter cake and an extracting agent ethyl acetate is 1:1(kg: L), the washing temperature is 80 ℃ and the time is 60 ℃) and filtering (sequentially passes through the positive pressure filter, the drawstring filter and the microporous filter) are carried out to obtain extract liquor, and after the extract liquor is dried by a desolventizing and desolventizing dryer (the temperature is 150 ℃, the atmospheric pressure and the retention time is 60 minutes), 3.82kg (the pure wax content is 56%) of the montan wax is obtained, and 73.2L of the recovery solvent is obtained.

Example 2

The same procedure as in example 1 was followed, except that: lignite (pure wax content 4.8%) is sieved to prepare particles smaller than 1mm, 1000 kg of the particles are taken, 2000L of an extracting agent is added according to the mass/volume ratio of 1:2(kg: L) to prepare coal slurry, the coal slurry is pumped into a tubular extractor by using a coal slurry pump, and saturated steam at 120 ℃ is introduced into a jacket. Extracting in an extractor for 30 minutes, then separating liquid from solid in a separator, sequentially carrying out filtration, filter cake washing and filtration to obtain an extract, and carrying out desolventizing and drying to obtain 74.4kg of montan wax (54% of pure wax), and 1960L of a recovered solvent.

Example 3

The size of the tubular extractor used was: the inner diameter of the pipe is 50mm, the outer diameter is 60mm, the length of a single pipe is 50m, and the total length is 1200 m.

By the same method as in example 1, 3.6kg of montan wax (54% pure wax content) was finally obtained, and 73L of a solvent was recovered.

Example 4

The size of the tubular extractor used was: the inner diameter of the pipe is 10mm, the outer diameter is 15mm, the length of a single pipe is 50m, and the total length is 1200 m.

By the same method as in example 1, 3.2kg of montan wax (51% pure wax content) was obtained, and 73L of a solvent was recovered.

Example 5

The size of the tubular extractor used was: the inner diameter of the pipe is 20mm, the outer diameter is 30mm, the length of a single pipe is 50m, and the total length is 1200 m.

By the same method as in example 1, 3.6kg of montan wax (53% pure wax content) was finally obtained, and 73L of a solvent was recovered.

Example 6

The size of the tubular extractor used was: the inner diameter of the pipe is 60mm, the outer diameter is 70mm, the length of a single pipe is 50m, and the total length is 1200 m.

By the same method as in example 1, 3.4kg of montan wax (52% pure wax) was finally obtained, and 73L of a solvent was recovered.

Example 7

The size of the tubular extractor used was: the inner diameter of the pipe is 80mm, the outer diameter is 100mm, the length of a single pipe is 50m, and the total length is 1200 m.

Through the same process as in example 1, 2.9kg of montan wax (47% pure wax content) was obtained, and 72.5L of a solvent was recovered.

Example 8