Method for preparing effective gas by blending coal containing high alkali metal coal

Abstract

The invention discloses a method for preparing effective gas from coal blending containing high alkali metal coal, which comprises the following steps: S1, selecting mixed coal to prepare for trial burning, the mixed coal comprising alkali metal, ash, water and volatile components, and the mixed coal further comprising a plurality of acidic oxides and basic oxides; s2, coal gangue is selected and prepared to be matched with the mixed coal, wherein the coal gangue comprises acidic oxide, basic oxide and alkali metal; s3, the mixed coal matched with the coal gangue is put into a coal furnace to be subjected to trial burning, the trial burning time is not shorter than 5 days, the trial burning analysis result of the mixed coal matched with the coal gangue is recorded, the analysis result comprises effective gas, and the effective gas is carbon monoxide and hydrogen; s4, the mixed coal is put into a coal furnace to be subjected to independent trial burning, the trial burning time is not shorter than 2 days, and an independent trial burning analysis result of the mixed coal is recorded; according to the scheme, the yield of effective gas is increased, and meanwhile the production cost is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of high-alkali metal coal, and in particular relates to a method for preparing effective gas by blending high-alkali metal-containing coal. Background Art

[0002] The alkalinity of high-alkali metal coal is usually greater than 3% (according to the national standard "Classification and Code of Coal"), and the content of alkali metal elements (such as sodium, potassium, etc.) in the coal is significantly higher than that of ordinary coal. High-alkali metal coal has a low carbon-hydrogen ratio, high volatile matter, and poor combustion characteristics. It is prone to spontaneous combustion and has great environmental pollution; the energy utilization efficiency is low, and the calorific value is generally between 3000 and 5000 kcal / kg; it has good chemical reactivity and a wide range of applications.

[0003] In the current raw coal market, the coal from Xinjiang stands out for its relatively low price and sufficient supply. Although Xinjiang is rich in coal resources, the high alkali metal content and high chloride ion content in the coal cannot be ignored. These characteristics make traditional aerospace gasifiers face multiple challenges during operation, such as difficulty in water-cooling wall slagging, scaling of device pipelines, and corrosion of stainless steel pipelines. Therefore, the test burning of high-alkali metal coal becomes particularly important. The test burning results can provide more basis for the applicability of high-alkali metal coal. Effective gas is usually carbon monoxide and hydrogen, which are produced during the combustion of coal. The existing technology for preparing effective gas is

[0004] Therefore, the present invention provides a method for preparing effective gas by blending high-alkali metal-containing coal, which is obtained during the trial burning of high-alkali metal coal. Summary of the invention

[0005] In view of the problems raised by the above background technology, the purpose of the present invention is to provide a method for preparing effective gas by blending high-alkali metal coal, which is obtained during the trial burning of high-alkali metal coal.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing effective gas by blending coal containing high alkali metals, comprising the following steps;

[0008] S1: Selecting mixed coal for trial burning, wherein the mixed coal includes alkali metals, ash, moisture and volatile matter, and the mixed coal also includes a variety of acidic oxides and basic oxides;

[0009] S2: selecting coal gangue to be matched with mixed coal, wherein the coal gangue includes acidic oxides, alkaline oxides and alkali metals;

[0010] S3: putting the mixed coal and coal gangue into the coal furnace for trial burning, the trial burning time is not less than 5 days, and recording the analysis results of the trial burning of the mixed coal and coal gangue, the analysis results include effective gas, and the effective gas is carbon monoxide and hydrogen;

[0011] S4: Put the mixed coal into the coal furnace for separate trial burning, the trial burning time shall not be less than 2 days, and record the analysis results of the separate trial burning of the mixed coal;

[0012] S5: putting the mixed coal and pulverized coal into the coal furnace for trial burning, the trial burning time is not less than 1 day, and recording the analysis results of the trial burning of the mixed coal and pulverized coal separately, the pulverized coal includes alkali metals, ash, moisture and volatile matter, acidic oxides and basic oxides;

[0013] Specifically, the acidic oxides in S1, S2 and S5 all include silicon dioxide, aluminum oxide and titanium oxide, and the basic oxides all include potassium oxide, sodium oxide, iron oxide, calcium oxide and magnesium oxide;

[0014] S6: Put the pulverized coal into the coal furnace for trial burning, the trial burning time shall not be less than 1 day, and record the analysis results of the trial burning of the pulverized coal alone;

[0015] S7: Comprehensively compare several trial burning schemes and select the scheme with the most effective gas production.

[0016] It is further defined that the alkali metal content of the mixed coal in S1 is not less than 40%, the ash content of the mixed coal is 5%-10%, the moisture content of the mixed coal is 20%-30%, the volatile matter of the mixed coal is not less than 30%, the silicon dioxide content is not less than 20%, the aluminum oxide content is not less than 15%, the titanium oxide content is not less than 0.5%, the potassium oxide content is not less than 0.8%, the sodium oxide content is not less than 4%, the iron oxide content is not less than 18%, the calcium oxide content is not less than 20%, and the magnesium oxide content is not less than 5%.

[0017] It is further defined that the alkali metal content of the mixed coal in S1 is 47.75%, the ash content is 7.72%, the moisture content is 26.9%, the volatile matter is 31.51%, the silicon dioxide content is 23.65%, the aluminum oxide content is 15.8%, the titanium oxide content is 0.57%, the potassium oxide content is 0.85%, the sodium oxide content is 4.96%, the iron oxide content is 18.53%, the calcium oxide content is 23.51%, and the magnesium oxide content is 5.71%.

[0018] It is further defined that the silicon dioxide content in the S2 is not less than 50%, the aluminum oxide content is not less than 35%, the titanium oxide content is not less than 0.5%, the potassium oxide content is not less than 2%, the sodium oxide content is not less than 1%, the iron oxide content is not less than 3%, the calcium oxide content is not less than 0.5%, the magnesium oxide content is not less than 0.5%, and the alkali metal content is not less than 4%.

[0019] It is further defined that the silicon dioxide content in the S2 is 59.5%, the aluminum oxide content is 35.3%, the titanium oxide content is 0.95%, the potassium oxide content is 2.51%, the sodium oxide content is 1.42%, the iron oxide content is 3.11%, the calcium oxide content is 0.73%, the magnesium oxide content is 0.6%, and the alkali metal content is 4.44%.

[0020] It is further defined that the ratio of mixed coal to gangue in S3 is 94% to 95% for mixed coal and 5% to 6% for gangue, the trial burning time is 5 days, and the effective gas output accounts for more than 86%.

[0021] It is further defined that the mixed coal in S4 is tested burning alone, the moisture content of the mixed coal is 25% to 30%, the ash content of the mixed coal is 6% to 10%, the test burning time is 2 days, and the effective gas output accounts for more than 85%.

[0022] It is further defined that the mixed coal in S5 is combined with pulverized coal for trial burning, the ratio of the mixed coal to pulverized coal is 3:2, and the effective gas output accounts for more than 87%.

[0023] It is further defined that the pulverized coal in the S5 has a silicon dioxide content of 10.46%, an aluminum oxide content of 7.42%, a titanium oxide content of 0.25%, a potassium oxide content of 0.27%, a sodium oxide content of 4.7%, a iron oxide content of 7.61%, a calcium oxide content of 31.29%, a magnesium oxide content of 14.91%, and an alkali metal content of 53.81%.

[0024] It is further defined that the pulverized coal in S6 is tested separately, the moisture content of the pulverized coal is 22% to 26%, the ash content of the pulverized coal is 5% to 8%, the test burning time is 1 day, and the effective gas output accounts for more than 85%.

[0025] Beneficial effects of the present invention:

[0026] The present invention provides a method for preparing effective gas from high-alkali metal coal blending, by selecting the preparation method with the lowest cost and the highest effective gas yield through the following steps: blending mixed coal with coal gangue, burning mixed coal alone, blending mixed coal with pulverized coal, and burning pulverized coal alone:

[0027] Gas production per ton of coal after trial burning: When mixed with coal gangue, the gas production per ton of coal is 1400Nm 3 / h (effective gas output per ton of coal is 1230Nm 3 / h), which is about 260Nm lower than the current ratio. 3 / h; After burning pure Tianchi mixed coal, the gas production per ton of coal is 1520Nm 3 / h (effective gas output per ton of coal is 1370Nm 3 / h). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0029] Figure 1 It is a structural schematic diagram of an embodiment of a method for preparing effective gas by blending coal containing high alkali metals in the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0032] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] like Figure 1 As shown, a method for preparing effective gas by blending high-alkali metal-containing coal of the present invention comprises the following steps:

[0034] S1: Selecting mixed coal for trial burning, wherein the mixed coal includes alkali metals, ash, moisture and volatile matter, and the mixed coal also includes a variety of acidic oxides and basic oxides;

[0035] S2: selecting coal gangue to be matched with mixed coal, wherein the coal gangue includes acidic oxides, alkaline oxides and alkali metals;

[0036] S3: putting the mixed coal and coal gangue into the coal furnace for trial burning, the trial burning time is not less than 5 days, and recording the analysis results of the trial burning of the mixed coal and coal gangue, the analysis results include effective gas, and the effective gas is carbon monoxide and hydrogen;

[0037] S4: Put the mixed coal into the coal furnace for separate trial burning, the trial burning time shall not be less than 2 days, and record the analysis results of the separate trial burning of the mixed coal;

[0038] S5: putting the mixed coal and pulverized coal into the coal furnace for trial burning, the trial burning time is not less than 1 day, and recording the analysis results of the trial burning of the mixed coal and pulverized coal separately, the pulverized coal includes alkali metals, ash, moisture and volatile matter, acidic oxides and basic oxides;

[0039] Specifically, the acidic oxides in S1, S2 and S5 all include silicon dioxide, aluminum oxide and titanium oxide, and the basic oxides all include potassium oxide, sodium oxide, iron oxide, calcium oxide and magnesium oxide;

[0040] S6: Put the pulverized coal into the coal furnace for trial burning, the trial burning time shall not be less than 1 day, and record the analysis results of the trial burning of the pulverized coal alone;

[0041] S7: Comprehensively compare several trial burning schemes and select the scheme with the most effective gas production.

[0042] Embodiment 1:

[0043] Preferably, the alkali metal content of the mixed coal is not less than 40%, the ash content of the mixed coal is 5% to 10%, the moisture content of the mixed coal is 20% to 30%, the volatile matter of the mixed coal is not less than 30%, the silicon dioxide content is not less than 20%, the aluminum oxide content is not less than 15%, the titanium oxide content is not less than 0.5%, the potassium oxide content is not less than 0.8%, the sodium oxide content is not less than 4%, the iron oxide content is not less than 18%, the calcium oxide content is not less than 20%, and the magnesium oxide content is not less than 5%.

[0044] Preferably, the alkali metal content of the mixed coal is 47.75%, the ash content is 7.72%, the moisture content is 26.9%, the volatile matter is 31.51%, the silicon dioxide content is 23.65%, the aluminum oxide content is 15.8%, the titanium oxide content is 0.57%, the potassium oxide content is 0.85%, the sodium oxide content is 4.96%, the iron oxide content is 18.53%, the calcium oxide content is 23.51%, and the magnesium oxide content is 5.71%.

[0045] This scheme selects 10 kinds of raw coal from Wucaiwan mining area, and the characteristic test and analysis of each kind of coal are as follows:

[0046]

[0047]

[0048] Table 1 Coal type index of Wucaiwan mining area

[0049] Example 1 The indicators for selecting Tianchi Energy mixed coal are as follows:

[0050] (1) Ash content: The ash content of mixed coal is between 5% and 10%, which is about 5% lower than the ash content of normal coal entering the furnace.

[0051] (2) Moisture: The moisture content of mixed coal is high, and the detection analysis shows that it is between 20% and 30%, otherwise it will affect the processing capacity of the coal mill;

[0052] (3) Silicon-aluminum ratio: If the silicon-aluminum ratio in the ash is less than 1.0, it is relatively low.

[0053] Tianchi Energy mixed coal was selected to be burned with Maliantai gangue. Maliantai gangue has low ignition loss (high ash content) and the total amount of Si+Al in the ash composition is >80%. The ash composition and viscosity-temperature characteristics of the ash entering the furnace can be adjusted, as shown in the following table:

[0054]

[0055]

[0056] The Tianchi mixed coal mixed with coal gangue was selected for trial burning, the purpose of which was to increase the ash content of the coal entering the furnace and improve the viscosity-temperature characteristics. The trial burning lasted 5.2 days. The specific analysis indicators of the mixed coal are as follows:

[0057] Table 3 Tianchi Energy Coal Gangue Burning Index

[0058]

[0059] Preferably, the silicon dioxide content in the S2 is not less than 50%, the aluminum oxide content is not less than 35%, the titanium oxide content is not less than 0.5%, the potassium oxide content is not less than 2%, the sodium oxide content is not less than 1%, the iron oxide content is not less than 3%, the calcium oxide content is not less than 0.5%, the magnesium oxide content is not less than 0.5%, and the alkali metal content is not less than 4%.

[0060] Preferably, the S2 contains 59.5% silicon dioxide, 35.3% aluminum oxide, 0.95% titanium oxide, 2.51% potassium oxide, 1.42% sodium oxide, 3.11% iron oxide, 0.73% calcium oxide, 0.6% magnesium oxide and 4.44% alkali metals.

[0061] Preferably, the ratio of mixed coal to gangue in S3 is 94% to 95% for mixed coal and 5% to 6% for gangue, the trial burning time is 5 days, and the effective gas output accounts for more than 86%.

[0062] In summary, the coal quality analysis of Tianchi mixed coal blended with coal gangue is as follows:

[0063] (1) The moisture content of the mixed coal is 25% to 30%, and the moisture content of the coal entering the furnace is between 4.0 and 5.5, which is about 2% higher than that of normal coal. The moisture content of the raw coal is too high and the coal grinding system cannot dry the moisture content to below 3%.

[0064] (2) Ash content: 11.5% to 16.0%. Tianchi Energy Blended Coal is produced from an open-pit coal mine, and the coal quality itself fluctuates greatly.

[0065] (3) Calorific value: The calorific value of the pulverized coal entering the furnace is between 5600 and 5900 kcal, and the indicator is relatively stable, but the calorific value is about 400 to 600 kcal lower than that of normal coal.

[0066] (4) Ash melting point: The ash melting point of the coal entering the furnace is between 1150 and 1210°C, which is lower than the design index.

[0067] (5) The output of effective gas (carbon monoxide and hydrogen) accounts for 86.97%.

[0068] The indicators of the coal entering the furnace are basically consistent with the design indicators, and there is no obvious change in the coal quality indicators compared with the previous use of Tianchi Energy mixed coal: coal gangue = 94%: 6% ratio; after the optimization of the raw coal blending method, the quality of the coal entering the furnace is more stable than the first trial burning, and the blending effect is significantly improved compared with the last time; Tianchi Energy mixed coal is raw coal mined from open-pit mines, and the indicators of the raw coal itself fluctuate greatly, and the ash content of the coal entering the furnace fluctuates greatly after blending.

[0069] Embodiment 2:

[0070] Preferably, Tianchi mixed coal is selected for single burning, and the mixed coal is tested separately. The moisture content of the mixed coal is 25% to 30%, the ash content of the mixed coal is 6% to 10%, the test burning time is 2 days, and the effective gas output accounts for more than 85%. The specific analysis indicators of Tianchi Energy Mixed Coal are as follows:

[0071] Table 4 Tianchi Energy Single Burning Index

[0072]

[0073] In summary, the coal quality analysis of Tianchi mixed coal single combustion scheme is as follows:

[0074] (1) Moisture content: The moisture content of mixed coal is 25% to 30%, and the moisture content of coal entering the furnace is between 4.0 and 5.0, which means the moisture content is relatively high;

[0075] (2) Ash content: The ash content of the coal entering the furnace is 6%-10%, which is about 4% lower than normal coal.

[0076] (3) Calorific value: The calorific value of the coal entering the furnace is between 6000 and 6300 kcal, and the indicator is relatively stable.

[0077] (4) Ash melting point: The melting point of the coal ash entering the furnace is between 1140 and 1230°C, and the ash melting point fluctuates greatly.

[0078] (5) The output of effective gas (carbon monoxide and hydrogen) accounts for 85.72%.

[0079] After Tianchi Energy's mixed coal is burned alone, the coal quality is more stable than the proportioned coal.

[0080] Embodiment three: Preferably, mixed coal is combined with pulverized coal for trial burning, the ratio of mixed coal: pulverized coal is 3:2, the trial burning time is 1 day, the effective gas output accounts for more than 87%, the silicon dioxide content of the pulverized coal is 10.46%, the aluminum oxide content is 7.42%, the titanium oxide content is 0.25%, the potassium oxide content is 0.27%, the sodium oxide content is 4.7%, the iron oxide content is 7.61%, the calcium oxide content is 31.29%, the magnesium oxide content is 14.91%, and the alkali metal content is 53.81%.

[0081] Table 5 Tianchi Energy Blending Index of Yihua Pulverized Coal

[0082]

[0083] In summary, the coal quality analysis of the Tianchi mixed coal and Yihua pulverized coal solution is as follows:

[0084] (1) Moisture content: The moisture content of raw coal is 22% to 28%. The moisture content of coal entering the furnace is between 4.0 and 5.5, which means the moisture content is relatively high.

[0085] (2) Ash content: The ash content of the coal entering the furnace is 7% to 9%, and the coal quality is stable.

[0086] (3) Calorific value: The calorific value of the coal entering the furnace is stable between 6000 and 6200 kcal.

[0087] (4) Ash melting point: The ash melting point of the coal entering the furnace is between 1160 and 1250°C, and the ash melting point is stable.

[0088] (5) The output of effective gas (carbon monoxide and hydrogen) accounts for 87.41%.

[0089] The Tianchi:Yihua=3:2 ratio is implemented, the coal quality is stable, and all indicators are within the control range.

[0090] Embodiment 4: Preferably, the pulverized coal is tested alone, the moisture content of the pulverized coal is 22% to 26%, the ash content of the pulverized coal is 5% to 8%, the test burning time is 1 day, and the effective gas output accounts for more than 85%.

[0091] Table 6 Yihua pulverized coal single combustion index

[0092]

[0093]

[0094] Coal quality analysis

[0095] (1) Moisture content: The moisture content of pulverized coal is 22% to 26%, while the moisture content of coal entering the furnace is relatively high at around 5.0%.

[0096] (2) Ash content: The ash content of the coal entering the furnace is 5% to 8%, and the ash content of the coal is stable.

[0097] (3) Calorific value: The calorific value of the coal entering the furnace is stable at around 6200 kcal.

[0098] (4) Ash melting point: The melting point of the coal ash entering the furnace is 1300~350℃, which is relatively high. The melting point of Yihua fly ash is 50~80℃ higher than normal.

[0099] (5) The output of effective gas (carbon monoxide and hydrogen) accounts for 85.39%.

[0100] The economic analysis of the trial burning is as follows:

[0101] Table 7 Economic indicators of trial burning

[0102]

[0103] Economic efficiency of trial burning:

[0104] (I) Coarse and fine slag carbon residue: During the test burning period, the coarse slag carbon residue was stable at an average of about 5%. The fine slag carbon residue was 17.89% on average when mixed with gangue, and the carbon conversion rate was about 97.3%; after coal was burned alone, the fine slag carbon residue rose to about 27%, and the carbon conversion rate was about 98.0%. Analysis of the reasons: After single burning, the ash content of the coal entering the furnace decreased, and the percentage increased while the carbon residue remained unchanged.

[0105] (II) Coal-to-methanol ratio: When coal gangue is mixed, the coal gangue consumption per ton of methanol is about 1.72 tons, which increases coal consumption by 0.32 tons / ton compared with the current ratio (the net coal consumption after removing the coal gangue is 1.63 tons per ton of methanol); after coal is burned alone, the coal consumption per ton of methanol is about 1.64 tons.

[0106] (III) Gas production per ton of coal: When mixed with gangue, the gas production per ton of coal is 1400Nm 3 / h (effective gas output per ton of coal is 1230Nm 3 / h), which is about 260Nm lower than the current ratio. 3 / h. After burning pure Tianchi mixed coal, the gas production per ton of coal is 1520Nm 3 / h (effective gas output per ton of coal is 1370Nm 3 / h).

[0107] (IV) Cost of raw coal per ton: The ex-factory price of Tianchi mixed coal used by the patent applicant is currently RMB 422 / ton. The cost of methanol raw coal blended with coal gangue is about RMB 720, which is about RMB 120 / ton lower than the current ratio. The cost of single-burning methanol raw coal is about RMB 690, which is about RMB 150 / ton lower than the current ratio.

[0108] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing effective gas by blending coal containing high alkali metals, characterized in that , including the following steps; S1: Selecting mixed coal for trial burning, wherein the mixed coal includes alkali metals, ash, moisture and volatile matter, and the mixed coal also includes a variety of acidic oxides and basic oxides; S2: selecting coal gangue to be matched with mixed coal, wherein the coal gangue includes acidic oxides, alkaline oxides and alkali metals; S3: putting the mixed coal and coal gangue into the coal furnace for trial burning, the trial burning time is not less than 5 days, and recording the analysis results of the trial burning of the mixed coal and coal gangue, the analysis results include effective gas, and the effective gas is carbon monoxide and hydrogen; S4: Put the mixed coal into the coal furnace for separate trial burning, the trial burning time shall not be less than 2 days, and record the analysis results of the separate trial burning of the mixed coal; S5: putting the mixed coal and pulverized coal into the coal furnace for trial burning, the trial burning time is not less than 1 day, and recording the analysis results of the trial burning of the mixed coal and pulverized coal separately, the pulverized coal includes alkali metals, ash, moisture and volatile matter, acidic oxides and basic oxides; Specifically, the acidic oxides in S1, S2 and S5 all include silicon dioxide, aluminum oxide and titanium oxide, and the basic oxides all include potassium oxide, sodium oxide, iron oxide, calcium oxide and magnesium oxide; S6: Put the pulverized coal into the coal furnace for trial burning, the trial burning time shall not be less than 1 day, and record the analysis results of the trial burning of the pulverized coal alone; S7: Comprehensively compare several trial burning schemes and select the scheme with the most effective gas production.

2. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The alkali metal content of the mixed coal in S1 is not less than 40%, the ash content of the mixed coal is 5%-10%, the moisture content of the mixed coal is 20%-30%, the volatile matter of the mixed coal is not less than 30%, the silicon dioxide content is not less than 20%, the aluminum oxide content is not less than 15%, the titanium oxide content is not less than 0.5%, the potassium oxide content is not less than 0.8%, the sodium oxide content is not less than 4%, the iron oxide content is not less than 18%, the calcium oxide content is not less than 20%, and the magnesium oxide content is not less than 5%.

3. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 2, characterized in that: The alkali metal content of the mixed coal in S1 is 47.75%, the ash content is 7.72%, the moisture content is 26.9%, the volatile matter is 31.51%, the silicon dioxide content is 23.65%, the aluminum oxide content is 15.8%, the titanium oxide content is 0.57%, the potassium oxide content is 0.85%, the sodium oxide content is 4.96%, the iron oxide content is 18.53%, the calcium oxide content is 23.51%, and the magnesium oxide content is 5.71%.

4. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The S2 contains not less than 50% silicon dioxide, not less than 35% aluminum oxide, not less than 0.5% titanium oxide, not less than 2% potassium oxide, not less than 1% sodium oxide, not less than 3% iron oxide, not less than 0.5% calcium oxide, not less than 0.5% magnesium oxide and not less than 4% alkali metal.

5. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 4, characterized in that: The S2 contains 59.5% silicon dioxide, 35.3% aluminum oxide, 0.95% titanium oxide, 2.51% potassium oxide, 1.42% sodium oxide, 3.11% iron oxide, 0.73% calcium oxide, 0.6% magnesium oxide and 4.44% alkali metal.

6. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The ratio of mixed coal to gangue in the S3 is 94% to 95% for mixed coal and 5% to 6% for gangue. The trial burning time is 5 days, and the effective gas output accounts for more than 86%.

7. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The mixed coal in S4 was tested burning separately, the moisture content of the mixed coal was 25% to 30%, the ash content of the mixed coal was 6% to 10%, the test burning time was 2 days, and the effective gas output accounted for more than 85%.

8. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The mixed coal in S5 was tested with pulverized coal, the ratio of the mixed coal to pulverized coal was 3:2, and the effective gas output accounted for more than 87%.

9. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The pulverized coal in the S5 has a silicon dioxide content of 10.46%, an aluminum oxide content of 7.42%, a titanium oxide content of 0.25%, a potassium oxide content of 0.27%, a sodium oxide content of 4.7%, a iron oxide content of 7.61%, a calcium oxide content of 31.29%, a magnesium oxide content of 14.91%, and an alkali metal content of 53.81%.

10. The method for preparing effective gas by blending high-alkali metal-containing coal according to claim 1, characterized in that: The pulverized coal in S6 was tested separately, the moisture content of the pulverized coal was 22% to 26%, the ash content of the pulverized coal was 5% to 8%, the test burning time was 1 day, and the effective gas output accounted for more than 85%.

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