CN114836250A

CN114836250A - Fluxing agent, preparation method and application thereof, and method for changing ash fusion characteristics of coal

Info

Publication number: CN114836250A
Application number: CN202210345897.6A
Authority: CN
Inventors: 姚敏; 杨磊; 杨英; 杨会军; 蔚永清; 井云环; 金政伟; 吴跃; 马银剑
Original assignee: National Energy Group Ningxia Coal Industry Co Ltd
Current assignee: National Energy Group Ningxia Coal Industry Co Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2022-08-02
Anticipated expiration: 2042-03-31
Also published as: CN114836250B

Abstract

The invention relates to the field of coal chemical industry, and discloses a fluxing agent, a preparation method and application thereof, and a method for changing ash fusion characteristics of coal. The fluxing agent contains calcium oxide, ferric oxide, silicon dioxide, aluminum oxide and magnesium oxide; wherein, based on the total weight of the fluxing agent, the content of calcium oxide is 20-35 wt%, the content of ferric oxide is 15-30 wt%, the content of silicon dioxide is 20-35 wt%, the content of aluminum oxide is 10-20 wt%, and the content of magnesium oxide is 1-9 wt%. The fluxing agent can obviously reduce the ash fusion temperature of coal after being mixed with the coal, change the ash viscosity-temperature characteristic type of the coal, reduce the gasification operation temperature, reduce the coal consumption in the gasification process and have obvious energy-saving effect.

Description

Fluxing agent, preparation method and application thereof, and method for changing ash fusion characteristics of coal

Technical Field

The invention relates to the field of coal chemical industry, and discloses a fluxing agent and a preparation method thereof, application of the fluxing agent in changing ash fusion characteristics of coal, and a method for changing the ash fusion characteristics of coal.

Background

Coal gasification is an important component of clean coal technology, and converts cheap coal into clean coal gas, so that the clean coal gas can be used for producing chemical products. The coal gasification technology is one of key technologies in coal chemical industry, and most of gasification furnaces operated by domestic coal chemical enterprises currently prepare synthesis gas by taking coal water slurry as a raw material. The coal water slurry is prepared from coal and water, but not all the coal can be prepared into the coal water slurry to be used as the gasification furnace. When the ash melting point T4 of the coal sample is too high, the coal sample cannot be used, and the ash melting point needs to be adjusted. Conventionally, a flux such as calcium oxide is added to adjust the ash melting point T4, but the amount added is large.

Disclosure of Invention

The invention aims to overcome the problem of large addition amount of a fluxing agent such as calcium oxide for adjusting an ash melting point T4 in the prior art, and provides the fluxing agent, a preparation method thereof and application of the fluxing agent in changing ash melting characteristics of coal.

In order to achieve the above object, a first aspect of the present invention provides a flux containing calcium oxide, iron oxide, silica, alumina, and magnesium oxide;

wherein, based on the total weight of the fluxing agent, the content of calcium oxide is 20-35 wt%, the content of ferric oxide is 15-30 wt%, the content of silicon dioxide is 20-35 wt%, the content of aluminum oxide is 10-20 wt%, and the content of magnesium oxide is 1-9 wt%.

A second aspect of the present invention provides a method for preparing the flux as described above, the method comprising: and (3) combusting the coal sample to obtain coal ash, and optionally mixing the coal ash with an oxide to obtain the fluxing agent.

A third aspect of the invention provides the use of a fluxing agent as described above to modify the ash fusion characteristics of coal.

In a fourth aspect, the present invention provides a method of modifying the ash fusion characteristics of coal, the method comprising: the fluxing agent and optional auxiliary fluxing agent as described above are mixed with the coal to obtain a mixed coal material.

The fluxing agent disclosed by the invention has specific components and compositions thereof, can obviously reduce the ash melting point of coal and change the ash viscosity-temperature characteristic of the coal under the condition of low addition amount, can keep a large temperature difference between T4 and T1, reduces the gasification operation temperature, reduces the coal consumption in the gasification process, provides a large operation window for a gasification furnace, and has an obvious energy-saving effect.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and these ranges or values should be understood to encompass values close to these 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.

The inventor of the invention finds that the coal ash generated by burning the coal in Nindong coal mine can obviously reduce the ash melting point of the coal and change the ash viscosity-temperature characteristic of the coal in Nindong coal mine in the research process. Fluxes formulated with a variety of coal ashes or coal ashes and oxides can also achieve similar effects depending on their composition.

Based on the above findings, the present invention provides in a first aspect a flux comprising calcium oxide, iron oxide, silica, alumina and magnesium oxide;

wherein, based on the total weight of the flux, the content of calcium oxide is 20-35 wt% (e.g. can be 20, 23, 26, 29, 32, 35 wt% and any range between any two values), the content of iron oxide is 15-30 wt% (e.g. can be 15, 16, 18, 20, 22, 24, 26, 28, 30 wt% and any range between any two values), the content of silica is 20-35 wt% (e.g. can be 20, 22, 24, 26, 28, 30, 32, 34, 35 wt% and any range between any two values), the content of alumina is 10-20 wt% (e.g. can be 10, 12, 14, 16, 18, 20 wt% and any range between any two values), the content of magnesium oxide is 1-9 wt% (e.g. can be 1, 3. 5, 7, 9 wt%, and any range of compositions between any two values).

Preferably, the content of calcium oxide is 20-30 wt%, the content of iron oxide is 17-26 wt%, the content of silicon dioxide is 22-32 wt%, the content of aluminum oxide is 12-18 wt%, and the content of magnesium oxide is 3-7 wt%, based on the total weight of the flux. Within the preferred range, the ability of the flux to change the ash fusion characteristics of the coal can be further improved.

The flux may also contain salts and oxides of other trace elements, i.e. these components together with the above-mentioned oxides constitute the flux.

Preferably, the flux further comprises at least one of sodium oxide, potassium oxide and titanium oxide.

Preferably, the flux comprises 0 to 3 wt.% (e.g., may be 0, 0.5, 1, 1.5, 2, 2.5, 3 wt.%), 0 to 2 wt.% (e.g., may be 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2 wt.% and any range therebetween), and 0 to 1.5 wt.% (e.g., may be 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.5 wt.% and any range therebetween), based on the total weight of the flux.

More preferably, the content of sodium oxide is 1.5 to 3 wt%, the content of potassium oxide is 0.5 to 1.5 wt%, and the content of titanium oxide is 0.5 to 1 wt%, based on the total weight of the flux.

The fluxing agent is preferably coal ash obtained after coal combustion in Nindong coal mines, and based on the total weight of the fluxing agent, the fluxing agent comprises 23-25 wt% of calcium oxide, 19-21 wt% of iron oxide, 28-31 wt% of silicon dioxide, 14-17 wt% of aluminum oxide, 4-6 wt% of magnesium oxide, 2-3 wt% of sodium oxide, 0.8-1.5 wt% of potassium oxide and 0.5-1 wt% of titanium oxide.

The flux may be a mixture of plural kinds of coal ash or a mixture of coal ash and an oxide, and preferably, the flux contains at least coal ash.

The content of oxides in the flux can be determined by an X-ray fluorescence spectrometer.

It should be understood that the combustion refers to complete combustion.

The coal sample may be an existing available coal sample, and when the components of the coal ash after the coal sample is combusted are within the component content of the fluxing agent, the fluxing agent (such as coal ash obtained from coal mine Ningdong) can be obtained directly without post-treatment; if the coal ash after the coal sample is combusted has components which are not in the content of the fluxing agent, the content of each component can be adjusted through post-treatment to obtain the fluxing agent.

The oxide may be any kind of oxide existing as long as the content of the obtained flux component can be made appropriate, and preferably, the oxide is selected from at least one oxide of calcium, iron, silicon, aluminum, magnesium, sodium, potassium, and titanium.

Wherein the type of the coal is not particularly required, and the origin of the coal are not required. By mixing the fluxing agent of the first aspect with the coal, the ash fusion point of the coal can be lowered, changing its ash visco-thermal characteristics.

The ash melting point T4 of the coal is reduced by mixing to meet the requirement of coal gasification.

In a preferred embodiment of the present invention, the coal has an ash melting point T4 of 1300-: the fluxing agent is mixed with the coal.

The amount of flux may be selected within wide limits and preferably the ratio of the amount of flux to the amount of coal is 1: 60-150 (e.g., 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100, 1:105, 1:110, 1:115, 1:120, 1:125, 1:130, 1:145, 1:150, and any range therebetween).

When the ash melting point T4 of the coal is greater than 1400 ℃, the process preferably comprises: the flux, optionally an auxiliary flux, and coal are mixed, i.e. the ash melting point T4 can be lowered by adding an auxiliary flux (e.g. iron oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, etc.).

Preferably, the ratio of the total amount of flux and auxiliary flux to the amount of coal is 1: 20-100 (e.g., can be 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, 1:100, and any range between any two values).

Preferably, the ratio of the addition amounts of the auxiliary flux and the flux is 1: 1.5-10, such as 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, and any range therebetween, more preferably 1: 1.5-4.

In the invention, the ash melting point of the coal sample is measured according to the method for measuring the coal ash meltability of the national standard GBT 219-.

When the ash fusion characteristics of coal were analyzed by the pyramid method, 4 characteristic temperatures T1-T4 were obtained, where T1 is the temperature at which the tip of the pyramid begins to round or bend, T2 is the temperature at which the tip of the ash cone bends over a flat disc or into a sphere, T3 is the temperature at which the ash cone approximates a hemisphere, i.e., is about half the base length, and T4 is the temperature at which the ash cone melts into a thin layer having a height of 1.5mm or less.

The present invention will be described in detail below by way of examples.

In the following examples, the ash fusion point T1-T4 of coal samples was measured according to the method for measuring the ash fusion property of coal under the national standard GBT 219-.

The composition of the fluxing agent is determined by adopting an X fluorescence spectrometer method.

In the following examples, materials and reagents used were obtained commercially unless otherwise specified.

Coal sample I and coal sample II were both produced from Ningxia and had ash melting points T1-T4 shown in tables 2 and 4, respectively.

Example 1

This example illustrates the preparation of the fluxing agent and the method of modifying the ash fusion characteristics of coal according to the present invention.

And (3) taking a coal sample of Nindong coal mine, and completely burning to obtain coal ash, namely obtaining the fluxing agent X1. Wherein the average content of each component is as follows: based on the total weight of the flux, the content of calcium oxide was 24.04 wt%, the content of iron oxide was 20.34 wt%, the content of silica was 29.32 wt%, the content of alumina was 15.48 wt%, the content of magnesium oxide was 4.98 wt%, the content of sodium oxide was 2.67 wt%, the content of potassium oxide was 1.32 wt%, and the content of titanium oxide was 0.88 wt%.

After mixing the flux, optional auxiliary flux and the coal sample I in the amounts indicated in table 1, the ash melting point of the mixed material was determined, and the specific results are shown in table 2.

TABLE 1

TABLE 2

Numbering	T1/℃	T2/℃	T3/℃	T4/℃
					Coal sample I	1273	1310	1355	1390
N1	1260	1270	1280	1320
					N2	1265	1280	1310	1355
N3	1240	1250	1258	1270

Example 2

And taking another coal sample of the Nindong coal mine, and completely burning to obtain coal ash, namely obtaining a fluxing agent X2. Wherein the average content of each component is as follows: based on the total weight of the flux, the content of calcium oxide was 23.44 wt%, the content of iron oxide was 19.18 wt%, the content of silica was 30.57 wt%, the content of alumina was 16.29 wt%, the content of magnesium oxide was 5.57 wt%, the content of sodium oxide was 2.05 wt%, the content of potassium oxide was 0.96 wt%, and the content of titanium oxide was 0.74 wt%.

And taking a coal sample of the Jushan coal mine, and completely burning to obtain the coal ash. Wherein the average content of each component is as follows: based on the total weight of the coal ash, the content of calcium oxide was 14.5 wt%, the content of iron oxide was 4.65 wt%, the content of silica was 53.6 wt%, the content of alumina was 18.9 wt%, the content of magnesium oxide was 1.71 wt%, the content of sodium oxide was 0.46 wt%, the content of potassium oxide was 0.58 wt%, and the content of titanium oxide was 1.14 wt%. Oxides were optionally added to the coal ash to obtain flux P1 of substantially the same composition as X1.

A commercially available oxide is taken, and a fluxing agent P2 with basically the same content is prepared according to the component composition of X1.

After 0.4g of flux and 10g of coal sample II were mixed, the ash melting point of the mixed material was measured, and the specific results are shown in Table 3.

TABLE 3

Numbering	T1/℃	T2/℃	T3/℃	T4/℃
					Coal sample II	》1500	》1500	》1500	》1500
X1	1240	1251	1262	1271
					X2	1243	1258	1265	1280
P1	1269	1273	1290	1315
					P2	1290	1320	1345	1350

The ash melting point of a coal sample can be reduced more effectively by using either the coal ash alone or a mixture containing the coal ash as a fluxing agent than by using the oxide alone or a combination of different oxides. In addition, it was found during the experiment that the flux P1 described in the examples was significantly better effective for lowering the ash melting point of coal than either iron oxide or calcium oxide or a mixture thereof used alone at the same weight.

In addition, the extra oxide is added to reduce the ash melting point of the coal sample, so that the ash content of the coal ash is artificially increased, the indexes such as heat productivity and the like are reduced, the quality of the coal is reduced, and the energy consumption of an industrial device is increased.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A flux, characterized in that the flux contains calcium oxide, iron oxide, silica, alumina and magnesium oxide;

2. The flux of claim 1, wherein the calcium oxide is present in an amount of 20 to 30 wt%, the iron oxide is present in an amount of 17 to 26 wt%, the silica is present in an amount of 22 to 32 wt%, the alumina is present in an amount of 12 to 18 wt%, and the magnesium oxide is present in an amount of 3 to 7 wt%, based on the total weight of the flux.

3. The flux of claim 1 or 2, wherein the flux further comprises at least one of sodium oxide, potassium oxide, and titanium oxide.

4. The flux of claim 3, wherein the sodium oxide is present in an amount of 0-3 wt.%, the potassium oxide is present in an amount of 0-2 wt.%, and the titanium oxide is present in an amount of 0-1.5 wt.%, based on the total weight of the flux;

preferably, the content of sodium oxide is 1.5-3 wt%, the content of potassium oxide is 0.5-1.5 wt%, and the content of titanium oxide is 0.5-1 wt%, based on the total weight of the flux.

5. A method of manufacturing a flux according to any one of claims 1 to 4, comprising: combusting the coal sample to obtain coal ash, and optionally mixing the coal ash with an oxide to obtain the fluxing agent;

preferably, the oxide is selected from oxides of at least one of calcium, iron, silicon, aluminum, magnesium, sodium, potassium, and titanium.

6. Use of a flux as claimed in any one of claims 1 to 4 to modify the ash fusion characteristics of coal.

7. A method of modifying the ash fusion characteristics of coal, the method comprising: mixing a fluxing agent according to any one of claims 1 to 4 and optionally an auxiliary fluxing agent with coal to obtain a mixed coal material.

8. The method as claimed in claim 7, wherein the ash melting point T4 of the coal is 1300-1400 ℃, the method comprising: mixing the fluxing agent and coal, wherein the ratio of the amount of the fluxing agent to the amount of the coal is 1: 60-150.

9. The process of claim 7, wherein the coal has an ash melting point T4 of greater than 1400 ℃, the process comprising: mixing the flux, optional auxiliary flux and coal;

preferably, the ratio of the total amount of flux and auxiliary flux to the amount of coal is 1: 20-100.

10. The method of claim 9, wherein the auxiliary flux is selected from at least one of iron oxide, calcium oxide, magnesium oxide, sodium oxide, and potassium oxide; preferably iron oxide;

preferably, the ratio of the addition amounts of the auxiliary flux and the flux is 1: 1.5-10, preferably 1: 1.5-4.