CN114836250B

CN114836250B - Fluxing agent, preparation method and application thereof and method for changing ash fusion characteristic of coal

Info

Publication number: CN114836250B
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: 2023-07-25
Anticipated expiration: 2042-03-31
Also published as: CN114836250A

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 the 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 characteristic of coal

Technical Field

The invention relates to the field of coal chemical industry, and discloses a fluxing agent and a preparation method thereof, wherein the fluxing agent is applied to changing the ash fusion characteristic of coal, and a method for changing the ash fusion characteristic of coal.

Background

Coal gasification is an important component of clean coal technology, and it converts inexpensive coal into clean gas, which can be used for producing chemical products. Coal gasification technology is one of key technologies of coal chemical industry, and most gasifiers operated by domestic coal chemical enterprises at present use coal water slurry as raw materials to prepare synthesis gas. The coal water slurry is prepared from coal and water, but not all coals can be used for preparing the coal water slurry as a 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. The conventional method for adjusting the ash melting point T4 is to add a flux such as calcium oxide, but the addition amount is large.

Disclosure of Invention

The invention aims to solve the problem of large addition amount of fluxing agent such as calcium oxide for adjusting ash melting point T4 in the prior art, and provides a 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 of preparing a flux as described above, the method comprising: and burning the coal sample to obtain coal ash, and optionally mixing the coal ash with oxide to obtain the fluxing agent.

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

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

The fluxing agent has specific components and compositions, 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, can keep larger temperature difference between T4 and T1, reduces gasification operation temperature, reduces coal consumption in the gasification process, provides a larger operation window for a gasification furnace, and has obvious energy-saving effect.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

The inventor of the invention finds that the coal ash after the coal of Ningdong coal mine burns can obviously reduce the ash melting point of the coal and change the ash viscosity-temperature characteristic of the coal in the research process. The flux prepared from various kinds of coal ash or coal ash and oxide can achieve similar effects according to the composition.

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

wherein the content of calcium oxide is 20-35 wt% (e.g., may 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., may 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., may 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., may be 10, 12, 14, 16, 18, 20 wt% and any range between any two values), and the content of magnesium oxide is 1-9 wt% (e.g., may be 1, 3, 5, 7, 9 wt% and any range between any two values) based on the total weight of the flux.

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 fluxing agent. Within the preferred range, the ability of the fluxing agent to alter the ash fusion characteristics of the coal can be further enhanced.

The fluxing agent may also contain salts and oxides of other trace elements, i.e. these components together with the oxides form the fluxing agent.

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

Preferably, the sodium oxide is present in an amount of 0 to 3 wt% (e.g., any range that may be 0, 0.5, 1, 1.5, 2, 2.5, 3 wt% and any range between two values), the potassium oxide is present in an amount of 0 to 2 wt% (e.g., any range that 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 between two values), and the titanium oxide is present in an amount of 0 to 1.5 wt% (e.g., any range that may be 0, 0.2, 0.4, 0.6, 0.8, 1.2, 1.4, 1.5 wt% and any range between two values), based on the total weight of the fluxing agent.

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

The fluxing agent is preferably coal ash obtained after coal combustion of Ningdong coal mine, and based on the total weight of the fluxing agent, the fluxing agent contains 23-25 wt% of calcium oxide, 19-21 wt% of ferric 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 also be a mixture of various kinds of coal ash, or a mixture of coal ash and oxide, and preferably the flux contains at least coal ash.

The content of oxides in the fluxing agent can be measured by an X-ray fluorescence spectrometer.

It should be understood that combustion refers to complete combustion.

The coal sample can 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 the coal ash obtained by combusting the coal obtained from Ningdong coal mine) can be directly obtained without post-treatment; if the components in the coal ash after the coal sample is burned have components not within 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 so long as the content of the resulting flux component can be made appropriate, and preferably the oxide is selected from oxides of at least one of calcium, iron, silicon, aluminum, magnesium, sodium, potassium, and titanium.

Wherein, the kind of the coal is not particularly required, and the place and source 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 reduced, changing its ash viscosity-temperature characteristics.

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

In a preferred embodiment of the invention, the ash fusion point T4 of the coal is 1300-1400 ℃, the method comprising: the fluxing agent is mixed with the coal.

The amount of fluxing agent may be chosen within a wide range, preferably the ratio of fluxing agent to coal by weight is 1:60-150 (e.g., may be 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 between any two values).

When the ash melting point T4 of the coal is greater than 1400 ℃, the method preferably comprises: the fluxing agent, optional auxiliary fluxing agent and coal are mixed, namely, the aim of reducing the ash melting point T4 can be achieved by adding auxiliary fluxing agents (such as ferric oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide and the like).

Preferably, the ratio of the total amount of fluxing agent and auxiliary fluxing agent to the amount of coal is 1 by weight: 20-100 (e.g., may 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 auxiliary fluxing agent to the amount of fluxing agent added is 1 by weight: 1.5-10, such as any range that may be 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 between any two values, more preferably 1:1.5-4.

In the invention, the ash melting point of the coal sample is measured according to the measuring method of the ash meltability of the national standard GBT 219-2008.

When analyzing the ash fusion characteristics of coal by the pyramid method, 4 characteristic temperatures T1-T4 can be obtained, wherein T1 is the temperature when the pyramid tip starts to round or bend, T2 is the temperature when the pyramid tip bends on a flat disc or takes the shape of a sphere, T3 is the temperature when the pyramid approximates a hemisphere, namely the temperature is about half of the bottom length, and T4 is the temperature when the pyramid melts into a thin layer with the height of less than 1.5 mm.

The present invention will be described in detail by examples.

In the following examples, ash fusion points T1-T4 of coal samples were measured according to the method for measuring the fusion properties of the national standard GBT 219-2008 coal ash.

The flux composition was determined by an X-ray fluorescence spectrometer method.

In the examples below, the materials and reagents used, unless otherwise specified, were all commercially available.

Coal sample I and coal sample II are both coal samples produced from Ningxia, and ash fusion points T1-T4 are shown in tables 2 and 4 respectively.

Example 1

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

Taking a coal sample of Ningdong coal mine, and preparing coal ash after complete combustion to obtain the fluxing agent X1. Wherein the average content of each component is as follows: based on the total weight of the fluxing agent, the content of calcium oxide is 24.04 wt%, the content of ferric oxide is 20.34 wt%, the content of silicon dioxide is 29.32 wt%, the content of aluminum oxide is 15.48 wt%, the content of magnesium oxide is 4.98 wt%, the content of sodium oxide is 2.67 wt%, the content of potassium oxide is 1.32 wt%, and the content of titanium oxide is 0.88 wt%.

After mixing the fluxing agent, optional auxiliary fluxing agent and coal sample I in the amounts described in Table 1, the ash melting point of the mixed materials was determined and the specific results are shown in Table 2.

TABLE 1

TABLE 2

Numbering device	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

This example illustrates the preparation of the fluxing agent of the present invention and its method of altering the ash fusion characteristics of coal.

Taking another coal sample of Ningdong coal mine, and preparing coal ash after complete combustion to obtain fluxing agent X2. Wherein the average content of each component is as follows: based on the total weight of the fluxing agent, the content of calcium oxide is 23.44 weight percent, the content of ferric oxide is 19.18 weight percent, the content of silicon dioxide is 30.57 weight percent, the content of aluminum oxide is 16.29 weight percent, the content of magnesium oxide is 5.57 weight percent, the content of sodium oxide is 2.05 weight percent, the content of potassium oxide is 0.96 weight percent, and the content of titanium oxide is 0.74 weight percent.

Taking a coal sample of the Jushan coal mine, and preparing coal ash after complete combustion. Wherein the average content of each component is as follows: based on the total weight of the coal ash, the content of calcium oxide is 14.5 wt%, the content of ferric oxide is 4.65 wt%, the content of silicon dioxide is 53.6 wt%, the content of aluminum oxide is 18.9 wt%, the content of magnesium oxide is 1.71 wt%, the content of sodium oxide is 0.46 wt%, the content of potassium oxide is 0.58 wt%, and the content of titanium oxide is 1.14 wt%. Oxides are selectively added to the soot to obtain a flux P1 having substantially the same composition as X1.

The commercial oxide was taken and flux P2 was formulated to have substantially the same content based on the composition of the components of X1.

After 0.4g of fluxing agent and 10g of coal sample II are respectively mixed, the ash melting point of the mixed materials is measured, and the specific results are shown in Table 3.

TABLE 3 Table 3

Numbering device	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 use of coal ash alone or a mixture containing coal ash as a fluxing agent can be more effective in lowering the ash fusion point of a coal sample than a single oxide or a combination of different oxides. In addition, during the experiment, it was found that the effect of the fluxing agent P1 described in the examples for lowering the ash fusion point of coal was significantly better than that of the iron oxide or the calcium oxide or the mixture thereof alone in the same weight.

In addition, the added oxide is used for reducing the melting point of the coal sample ash, so that the ash content of the coal ash is artificially increased, indexes such as heating value and the like are reduced, the quality of coal is reduced, and the energy consumption of an industrial device is increased.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A flux, characterized in that the flux contains 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 to 30 weight percent, the content of ferric oxide is 17 to 26 weight percent, the content of silicon dioxide is 22 to 32 weight percent, the content of aluminum oxide is 12 to 18 weight percent, and the content of magnesium oxide is 3 to 7 weight percent;

the fluxing agent at least contains coal ash.

2. The fluxing agent of claim 1, wherein the fluxing agent further comprises at least one of sodium oxide, potassium oxide, and titanium oxide.

3. A flux as claimed in claim 2 wherein the sodium oxide is present in an amount of 0 to 3 wt%, the potassium oxide is present in an amount of 0 to 2 wt% and the titanium oxide is present in an amount of 0 to 1.5 wt%, based on the total weight of the flux.

4. A flux according to claim 3 wherein the sodium oxide is present in an amount of 1.5 to 3 wt%, the potassium oxide is present in an amount of 0.5 to 1.5 wt% and the titanium oxide is present in an amount of 0.5 to 1 wt%, based on the total weight of the flux.

5. A process for producing a flux as defined in any one of claims 1 to 4, comprising: and burning the coal sample to obtain the fluxing agent.

6. A process for producing a flux as defined in any one of claims 1 to 4, comprising: and burning the coal sample to obtain coal ash, and mixing the coal ash with the oxide to obtain the fluxing agent.

7. The method of claim 6, wherein the oxide is selected from the group consisting of oxides of at least one of calcium, iron, silicon, aluminum, magnesium, sodium, potassium, and titanium.

8. Use of a fluxing agent according to any of claims 1 to 4, for modifying the ash fusion properties of coal.

9. A method of modifying ash fusion properties of coal, the method comprising: mixing the fluxing agent of any of claims 1-4 with coal to obtain a mixed coal material.

10. The method according to claim 9, wherein the method comprises: mixing the fluxing agent of any of claims 1-4 and the auxiliary fluxing agent with coal to obtain a mixed coal material.

11. The method of claim 9, wherein the coal has an ash fusion point T4 of 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 by weight: 60-150.

12. The method of claim 9, wherein the ash fusion point T4 of the coal is greater than 1400 ℃, the method comprising: the fluxing agent is mixed with the coal.

13. The method of claim 10, wherein the ash fusion point T4 of the coal is greater than 1400 ℃, the method comprising: the fluxing agent, auxiliary fluxing agent and coal are mixed.

14. The method of claim 13, wherein the ratio of the total amount of fluxing agent and auxiliary fluxing agent to the amount of coal is 1 by weight: 20-100.

15. The method of claim 13, wherein the auxiliary flux is selected from at least one of iron oxide, calcium oxide, magnesium oxide, sodium oxide, and potassium oxide.

16. The method of claim 15, wherein the auxiliary flux is iron oxide.

17. The method of claim 15, wherein the ratio of the auxiliary flux and the flux is added in an amount of 1 by weight: 1.5-10.

18. The method of claim 17 wherein the ratio of the auxiliary flux and the flux is added in an amount of 1:1.5-4 by weight.