Demetalization method for coal tar
阅读说明：本技术 一种煤焦油脱金属的方法 (Demetalization method for coal tar ) 是由 黄玉萍 韩江华 王树青 王卫平 夏国富 于 2020-06-18 设计创作，主要内容包括：本发明涉及煤焦油加工领域,公开了一种煤焦油脱金属的方法,该方法包括：将煤焦油与脱金属剂进行混合接触,其中,所述煤焦油中的酚类化合物的总含量为1-30重量％,金属总含量为50-500ppm,所述脱金属剂为季铵盐类化合物中的至少一种,所述脱金属剂和所述煤焦油的用量质量比为0.005-0.3：1。本发明提供的煤焦油脱金属的方法高效、环保且能够有效降低煤焦油中金属含量。(The invention relates to the field of coal tar processing, and discloses a coal tar demetalization method, which comprises the following steps: mixing and contacting coal tar and a demetallizing agent, wherein the total content of phenolic compounds in the coal tar is 1-30 wt%, the total content of metals is 50-500ppm, the demetallizing agent is at least one of quaternary ammonium salt compounds, and the mass ratio of the demetallizing agent to the coal tar is 0.005-0.3: 1. the method for demetallizing the coal tar is efficient and environment-friendly, and can effectively reduce the metal content in the coal tar.)
1. A method for demetallizing coal tar, comprising: mixing and contacting coal tar and a demetallizing agent, wherein the total content of phenolic compounds in the coal tar is 1-30 wt%, the total content of metals is 50-500ppm, the demetallizing agent is at least one of quaternary ammonium salt compounds, and the mass ratio of the demetallizing agent to the coal tar is 0.005-0.3: 1.
2. the process according to claim 1, wherein the total content of phenolic compounds in the coal tar is 5-25 wt.%, preferably 10-25 wt.%.
3. The method according to claim 1 or 2, wherein the amount of the demetallizing agent and the amount of the coal tar are in a mass ratio of 0.008-0.25: 1.
4. the method according to any one of claims 1 to 3, wherein the quaternary ammonium salt-based compound is selected from at least one of tetraalkylammonium halides and choline chloride;
preferably, the tetraalkylammonium halide is of the structure shown in formula (1),
wherein R is1、R2、R3And R4Each independently is C1-C4X is a halide ion;
preferably, R1、R2、R3And R4Each independently is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl;
preferably, R1、R2、R3And R4Less than 15, preferably less than 10;
preferably, X is Cl-、F-、Br-Or I-More preferably Cl-。
5. The method of claim 4, wherein the demetallizing agent is selected from at least one of tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, methyltriethylammonium chloride, and choline chloride.
6. The method of any one of claims 1-5, wherein the conditions of the mixing contact are at least: the temperature is 20-60 ℃, and the time is 5-60 min;
preferably, the conditions of the mixing contact at least satisfy: the temperature is 30-50 ℃, and the time is 15-30 min.
7. The method of any of claims 1-6, wherein the method further comprises: and (3) carrying out standing layering treatment on the mixture obtained after the mixing and contacting.
8. The method according to claim 7, wherein the standing time is 5-100 min; preferably 20-60 min.
9. The method of any of claims 1-8, wherein the coal tar comprises at least one of coal pyrolysis oil, coal direct liquefaction oil, and coal tar distillate oil.
10. The method of any of claims 1-9, wherein the phenolic compounds in the coal tar comprise substituted and unsubstituted phenols, preferably alkyl phenols.
Technical Field
The invention relates to the field of coal tar processing, in particular to a demetallization method for coal tar.
Background
The coal tar mainly contains Ca, Fe, Mg, Na, V, Ni, Al and the like, and the existence of the metal elements has great harm to the catalytic hydrogenation process of the coal tar, so that the coal tar can corrode and block production equipment and transmission pipelines, can cause catalyst poisoning inactivation and selectivity change, shortens the operation period of the device, and causes the yield of target products to be reduced. Therefore, before the coal tar is processed, the metal content in the raw material coal tar needs to be reduced as much as possible so as to meet the subsequent processing requirement.
At present, the method for removing metals in coal tar mainly comprises the following steps: filtration separation technology, centrifugal separation technology, electric desalting technology, hydrodemetallization technology and the like. The coal tar has high density, high viscosity and high content of phenolic substances, heterocyclic compounds and heavy components, so that the current is high during electric desalting, even an electric field is not applied, the optimized electric desalting process can meet the requirement of hydrogenation feeding, but the content of metals after the desalting is still high, and the consumption of a catalyst can be increased; the centrifugal separation technology is difficult to remove particles with small particle size and oil-soluble metal salt, most of the metal in the coal tar exists in the form of organic metal compound, and the removal effect is very limited by only depending on centrifugal separation; through a combined process of various technologies, such as centrifugal separation, chemical reaction demetalization, ash removal, electric desalting and dehydration, metal elements in the coal tar can be effectively removed, so that the requirements of a coal tar hydrogenation process are met, but the process is complex and high in cost; compared with other methods, the method has the best hydrodemetallization effect, but has the problems of large investment, difficult regeneration of the catalyst and difficult treatment.
Therefore, the existing coal tar metal removal method has the problems of poor removal effect, complex process, high cost and the like.
Disclosure of Invention
The invention aims to overcome the defects of poor separation effect, complex process and high cost of the metal removal process of the coal tar in the prior art.
In order to achieve the above object, the present invention provides a method for demetallizing coal tar, comprising: mixing and contacting coal tar and a demetallizing agent, wherein the total content of phenolic compounds in the coal tar is 1-30 wt%, the total content of metals is 50-500ppm, the demetallizing agent is at least one of quaternary ammonium salt compounds, and the mass ratio of the demetallizing agent to the coal tar is 0.005-0.3: 1.
the inventor finds that the coal tar demetallizing agent used in the coal tar demetallizing method provided by the invention can form a eutectic product with phenolic compounds in the coal tar, and metal compounds are dissolved in the eutectic product, so that the aim of efficiently, environmentally and effectively reducing the metal content in the coal tar can be fulfilled by quaternary ammonium salt compounds.
The method has the advantages of simple operation process, mild operation condition, no special requirement on equipment and low energy consumption.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
As previously mentioned, the present invention provides a method for demetallizing coal tar, comprising: mixing and contacting coal tar and a demetallizing agent, wherein the total content of phenolic compounds in the coal tar is 1-30 wt%, the total content of metals is 50-500ppm, the demetallizing agent is at least one of quaternary ammonium salt compounds, and the mass ratio of the demetallizing agent to the coal tar is 0.005-0.3: 1.
preferably, the total content of phenolic compounds in the coal tar is 5-25 wt%, more preferably 10-25 wt%.
Preferably, the mass ratio of the demetallization agent to the coal tar is 0.008-0.25: 1. that is, the present invention can achieve an excellent demetallization effect in coal tar by using a very small amount of the quaternary ammonium salt compound.
Preferably, the quaternary ammonium salt compound is at least one selected from the group consisting of tetraalkylammonium halides and choline chloride.
Preferably, the tetraalkylammonium halide is of the structure shown in formula (1),
wherein R is1、R2、R3And R4Each independently is C1-C4X is a halide ion.
In the formula (1), R1、R2、R3And R4Each may be the same or different.
Preferably, R1、R2、R3And R4Each independently being methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
Preferably, in said formula (1), R1、R2、R3And R4Less than 15, more preferably less than 10.
According to the invention, preferably, in said formula (1), R1、R2、R3And R4Each independently being methyl, ethyl or n-propyl.
X in the formula (1) is a salt-forming anion, preferably a halide ion. The halide ion may be F-、Cl-、Br-Or I-。
Preferably, X is Cl-、F-、Br-、I-More preferably Cl-Or Br-。
Particularly preferably, the demetallizing agent is at least one selected from the group consisting of tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride (i.e., tetra-n-propylammonium chloride), methyltriethylammonium chloride and choline chloride, in order to obtain a better metal removal effect.
The demetallizing agent can remove Ca, Fe, Mg, Na, V, Ni, Al and other metals in the coal tar.
The mixing contact of the present invention is preferably carried out under stirring conditions. The coal tar is fully contacted with the demetallization agent by stirring. In the present invention, the specific conditions for stirring are not particularly limited as long as sufficient contact between the coal tar and the demetallizing agent can be achieved.
According to a preferred embodiment, the conditions of the mixing contact are at least such that: the temperature is 20-60 ℃, and the time is 5-60 min.
More preferably, the conditions of the mixing contact at least satisfy: the temperature is 30-50 ℃, and the time is 15-30 min.
Preferably, the method further comprises: and (3) carrying out standing layering treatment on the mixture obtained after the mixing contact.
Preferably, the standing time is 5-100 min; more preferably 20 to 60 min.
Through standing and layering, the metal-enriched material removed by the demetallizing agent in the coal tar can be positioned at the lower layer of the mixture.
Preferably, the coal tar includes at least one of coal pyrolysis oil, coal direct liquefaction oil, and coal tar distillate oil.
Preferably, the phenolic compounds in the coal tar comprise substituted and unsubstituted phenols, with substituted phenols preferably being alkylphenols, such as C1-10Alkyl-substituted phenols of (a).
The demetallizing agent can be directly added into coal tar to be stirred.
The method can reduce the metal content in the coal tar to below 20 ppm.
The present invention will be described in detail below by way of examples. In the following examples, the raw materials used are those which are generally commercially available, unless otherwise specified.
Example 1
The demetallizing agent is tetraethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-1, magnetically stirring for 30min under the water bath heating at 30 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-1 and the coal tar-1 demetallized oil 1 are shown in a table 1, and the total metal content of the demetallized oil phase is less than 8.4 ppm.
TABLE 1
Metal content/mg/kg
Coal tar-1
Coal tar-1 demetallized oil 1
Fe
75.1
3.3
Ni
<0.1
<0.1
Cu
0.3
0.1
V
<0.1
<0.1
Na
19.6
2.1
Ca
2.4
0.7
Mg
<0.1
<0.1
Pb
<0.1
<0.1
Al
4.0
0.7
K
0.8
1.1
Total metal
102.6
<8.4
Total content of phenolic compounds,% by weight
10
/
Example 2
The demetallizing agent is tetraethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-1, magnetically stirring for 30min under the heating of water bath at 50 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-1 and the coal tar-1 demetallized oil 2 are shown in a table 2, and the total metal content of the demetallized oil phase is less than 8.0 ppm.
TABLE 2
Example 3
The demetallizing agent is tetraethylammonium chloride.
Adding 0.4g of demetallizing agent into 50g of coal tar-1, magnetically stirring for 40min under the water bath heating at 30 ℃, standing for 40min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-1 and the coal tar-1 demetallized oil 3 are shown in a table 3, and the total metal content of the demetallized oil phase is less than 8.1 ppm.
TABLE 3
Metal content mg/kg
Coal tar-1
Coal tar-1 demetallized oil 3
Fe
75.1
3.1
Ni
<0.1
<0.1
Cu
0.3
0.1
V
<0.1
<0.1
Na
19.6
2.0
Ca
2.4
0.7
Mg
<0.1
<0.1
Pb
<0.1
<0.1
Al
4.0
0.7
K
0.8
1.1
Total metal
102.6
<8.1
Total content of phenolic compounds,% by weight
10
/
Example 4
The demetallizing agent is tetramethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-1, magnetically stirring for 30min under the water bath heating at 30 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-1 and the coal tar-1 demetallized oil 4 are shown in a table 4, and the total metal content of the demetallized oil phase is less than 9.9 ppm.
TABLE 4
Metal content mg/kg
Coal tar-1
Coal tar-1 demetallized oil 4
Fe
75.1
3.8
Ni
<0.1
<0.1
Cu
0.3
0.1
V
<0.1
<0.1
Na
19.6
2.9
Ca
2.4
0.7
Mg
<0.1
<0.1
Pb
<0.1
<0.1
Al
4.0
1.0
K
0.8
1.0
Total metal
102.6
<9.9
Total content of phenolic compounds,% by weight
10
/
Example 5
The demetallizing agent is tetraethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-2, magnetically stirring for 30min under the water bath heating at 30 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-2 and the coal tar-2 demetallized oil 1 are shown in a table 5, and the total metal content of the demetallized oil phase is less than 19.7 ppm.
TABLE 5
Metal, mg/kg
Coal tar-2
Coal tar-2 demetallized oil 1
Fe
66.9
2.7
Ni
<0.1
<0.1
Cu
<0.1
<0.1
V
0.2
0.1
Na
8.4
0.7
Ca
126
14.7
Mg
5.6
<0.1
Pb
0.1
<0.1
Al
19.9
0.7
K
1
0.4
Total metal
228.1
<19.7
Total content of phenolic compounds,% by weight
18
/
Example 6
The demetallizing agent is tetraethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-3, magnetically stirring for 30min under the water bath heating at 30 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-3 and the coal tar-3 demetallized oil 1 are shown in a table 6, and the total metal content of the demetallized oil phase is less than 20 ppm.
TABLE 6
Metal, mg/kg
Coal tar-3
Coal tar-3 demetallized oil 1
Fe
81.5
3.2
Ni
<0.1
<0.1
Cu
<0.1
<0.1
V
<0.1
<0.1
Na
4.8
0.2
Ca
174
15.1
Mg
3.6
<0.1
Pb
<0.1
<0.1
Al
20.9
0.7
K
0.9
0.3
Total metal
285.7
<20
Total content of phenolic compounds,% by weight
22
/
Example 7
The demetallizing agent is tetraethylammonium chloride.
Adding 0.5g of demetallizing agent into 50g of coal tar-4, magnetically stirring for 30min under the water bath heating at 30 ℃, standing for 30min, and separating an upper layer and a lower layer, wherein the upper layer is demetallized oil, the lower layer is a metal enrichment phase, the metal contents of the coal tar-4 and the coal tar-4 demetallized oil 1 are shown in a table 7, and the total metal content of the demetallized oil phase is less than 9.6 ppm.
TABLE 7
Example 8
The demetallizing agent was 0.5g of tetra-n-propylammonium chloride.
The rest is the same as in example 1.
The metal content of coal tar-1 and coal tar-1 demetallized oil 5 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 7.9 ppm.
Example 9
The demetallizing agent was 0.5g of methyltriethylammonium chloride.
The rest is the same as in example 1.
The metal content of the coal tar-1 and coal tar-1 demetallized oil 6 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 8.9 ppm.
Example 10
The demetallizing agent was 0.5g of choline chloride.
The rest is the same as in example 1.
The metal content of coal tar-1 and coal tar-1 demetallized oil 7 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 13.6 ppm.
Example 11
The demetallizing agent was 0.3g of tetraethylammonium chloride.
The rest is the same as in example 1.
The metal content of the coal tar-1 and coal tar-1 demetallized oil 8 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 9.0 ppm.
Example 12
The demetallizing agent was 15g of tetraethylammonium chloride.
The rest is the same as in example 1.
The metal content of coal tar-1 and coal tar-1 demetallized oil 9 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 8.6 ppm.
Example 13
The demetallizing agent was 10g of tetraethylammonium chloride.
The rest is the same as in example 1.
The metal content of the coal tar-1 and coal tar-1 demetallized oil 10 is shown in Table 8, and the total metal content of the demetallized oil phase is less than 8.0 ppm.
TABLE 8
Comparative example 1
And carrying out dephenolization treatment on the coal tar-1 by adopting an NaOH alkaline washing method to obtain the D-coal tar with the total content of phenolic compounds of 0.6 weight percent and the metal content of 112 ppm.
And D-coal tar is adopted to replace the coal tar-1 in the example 1, and the rest is the same as that in the example 1, and demetallization treatment is carried out to obtain the D-coal tar demetallized oil.
The metal content of the D-coal tar demetallized oil was 106 ppm.
From the results, the coal tar demetallization method provided by the invention is efficient and environment-friendly, and can effectively reduce the metal content in the coal tar in the presence of a low-dosage demetallization agent.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
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