Coal-fired flue gas desulfurizer, preparation method and desulfurization method

Abstract

The invention belongs to the technical field of flue gas desulfurization, and particularly relates to a coal-fired flue gas desulfurizer, a preparation method and a desulfurization method, the coal-fired flue gas desulfurizer is prepared from the following raw materials by mass: 85-90% of CaCO3, 1% of KMnO4, 1% of KClO3, 4% of NaCl, 0.5% of Fe2O3, 1-3% of (CH3COO) 2Ca, and 2-5.5% of fly ash. The use conditions of the desulfurizer are as follows: the calcium-sulfur ratio is 1: 2, the particle size of calcium carbonate is 200 meshes, the temperature is 800-900 DEG C, the additive has direct influence on the desulfurization effect of the desulfurizer, and the concentration of sulfur dioxide in boiler flue gas can be reduced below the national standard by adding the additive.

Description

Technical Field

[0001] This invention belongs to the field of flue gas desulfurization technology, specifically relating to a coal-fired flue gas desulfurizing agent, its preparation method, and a desulfurization method. Background Technology

[0002] While industrial development promotes social progress, it also causes serious damage to our environment. Sulfur dioxide, nitrogen oxides, and particulate matter are among the main sources of environmental pollution. Therefore, the development and promotion of technologies for removing sulfur dioxide and nitrogen oxides are worthy of our discussion and in-depth research. Flue gas desulfurization and denitrification technology for boiler purification is widely used in the chemical industry for the purification of sulfur dioxide and nitrogen oxides.

[0003] Flue gas desulfurization (FGD) technology can be categorized into five methods based on the type of desulfurizing agent: (i) Calcium method, using calcium carbonate as the absorbent; (ii) Magnesium method, using magnesium oxide as the absorbent; (iii) Method using sodium sulfite as the absorbent; (iv) Ammonia method, using NH3 as the absorbent; and (v) Organic alkali method, using organic alkali as the absorbent.

[0004] Among these, the calcium method is the most widely used desulfurization technology. In-furnace calcium injection technology involves directly spraying dry absorbent onto the chain grate furnace. Limestone (CaCO3) powder is selected as the absorbent. In the chain grate furnace, the limestone is calcined into active CaO particles at 800 to 900 degrees Celsius. The reactions involved include:

[0005]

[0006] CaCO3 + SO2 → CaSO3 + CO2↑ (2)

[0007] CaSO3 + 1 / 2O2 → CaSO4 (3)

[0008] There are many factors affecting in-furnace calcium injection technology, such as the particle size of the absorbent, the injection temperature, and the calcium-to-sulfur ratio. These factors limit the improvement of desulfurization efficiency. Therefore, this invention provides a coal-fired flue gas desulfurizer with good desulfurization effect. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a coal-fired flue gas desulfurizing agent, its preparation method, and a desulfurization method. It uses porous calcium carbonate as the main raw material, adds suitable additives, and considers various influencing factors to prepare a coal-fired flue gas desulfurizing agent with good desulfurization effect.

[0010] The present invention is specifically implemented through the following technical solution.

[0011] The first objective of this invention is to provide a desulfurizing agent for coal-fired flue gas, which is made from the following raw materials in the indicated mass percentages: CaCO3 85-90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1-3%, and fly ash 2-5.5%.

[0012] Preferably, it is made from the following raw materials in the indicated mass percentages: CaCO3 85%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 3%, and fly ash 5.5%.

[0013] Preferably, the particle size of CaCO3 is 200 mesh.

[0014] Preferably, the calcium-to-sulfur ratio is 1:2.

[0015] A second objective of this invention is to provide a method for preparing the aforementioned coal-fired flue gas desulfurizing agent, comprising the following steps:

[0016] The following raw materials were weighed and weighed to prepare the product: CaCO3 85-90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1-3%, and fly ash 2-5.5%.

[0017] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0018] The third objective of this invention is to provide a method for desulfurizing coal-fired flue gas, comprising the following steps:

[0019] The desulfurizing agent for coal-fired flue gas described in the claims is sprayed onto the combustion furnace using an in-furnace calcium injection method. At 800-900℃, the desulfurizing agent solidifies the sulfur elements in the furnace, thereby reducing the SO2 content discharged from the flue.

[0020] Preferably, the combustion furnace is a chain grate furnace.

[0021] Preferably, the SO2 content emitted from the flue gas is measured using a ZR-3100 flue gas comprehensive analyzer.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention uses porous calcium carbonate with suitable combustion-supporting additives. Potassium permanganate and potassium chlorate are used as oxygen-supplying agents. Potassium permanganate decomposes at high temperatures to release oxygen, allowing sulfur dioxide in the coal seam to react with oxygen to generate sulfur trioxide. Furthermore, sulfur trioxide reacts with calcium oxide in the furnace to form calcium sulfate, increasing the sulfur fixation rate and also acting as a combustion aid, accelerating heat release and promoting complete combustion. Sodium chloride and ferric oxide are used as catalysts. The catalyst's main function is to promote the reaction between sulfur dioxide and minerals in the coal, making combustion easier. Another function of the catalyst is to reduce the activation energy required for coal combustion. Sodium chloride can increase the conversion rate and efficiency of the sulfur-fixing agent, while ferric oxide can inhibit the decomposition of calcium sulfate during calcium-based sulfur fixation, increasing the sulfur fixation rate. Calcium acetate and fly ash are both calcium-based desulfurizing agents. The alkaline slurry formed by dissolving alkaline substances such as calcium oxide contained in fly ash in water is used for desulfurization.

[0024] 2. The desulfurizing agent of this invention is used under the following conditions: calcium-to-sulfur ratio of 1:2, calcium carbonate particle size of 200 mesh, and temperature of 800-900 degrees Celsius. The additives have a direct impact on the desulfurization effect of the desulfurizing agent. Adding the additives can reduce the concentration of sulfur dioxide in boiler flue gas to below the national standard. Attached Figure Description

[0025] Figure 1 The effect of potassium permanganate content on desulfurization efficiency;

[0026] Figure 2 The effect of potassium chlorate content on desulfurization efficiency;

[0027] Figure 3 The effect of sodium chloride content on desulfurization efficiency;

[0028] Figure 4 The effect of ferric oxide content on desulfurization efficiency;

[0029] Figure 5 The effect of calcium acetate content on desulfurization efficiency;

[0030] Figure 6 The effect of fly ash content on desulfurization efficiency. Detailed Implementation

[0031] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0032] The sources of the raw materials used in this invention are shown in Table 1:

[0033] Table 1 Sources of raw materials used in this invention

[0034] Reagent Name Specification Manufacturer Calcium carbonate Industrial Pure Shandong Xiya Chemical Industry Co., Ltd. potassium permanganate Industrial Pure Tianjin Hedong District Hongyan Reagent Co., Ltd. Potassium chlorate Industrial Pure Shandong Xiya Chemical Industry Co., Ltd. Sodium chloride Industrial Pure Tianjin Hedong District Hongyan Reagent Co., Ltd. Ferric oxide Industrial Pure Xi'an Langguang Chemical Technology Co., Ltd. Calcium acetate Industrial Pure Tianjin Tianli Chemical Reagent Co., Ltd. fly ash Industrial Pure Shanghai Shanpu Chemical Co., Ltd.

[0035] Example 1

[0036] A desulfurizing agent for coal-fired flue gas is made from the following raw materials in the indicated mass percentages: CaCO3 85%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 3%, and fly ash 5.5%.

[0037] The specific dosages are as follows: CaCO3 93.5g, KMnO4 1.1g, KClO3 1.1g, NaCl 4.4g, Fe2O3 0.55g, (CH3COO)2Ca 3.30g, and fly ash 6.05g.

[0038] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0039] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0040] Example 2

[0041] A desulfurizing agent for coal-fired flue gas is made from the following raw materials in the indicated mass percentages: CaCO3 90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1.5%, and fly ash 2%.

[0042] Example 3

[0043] A desulfurizing agent for coal-fired flue gas is made from the following raw materials in the indicated mass percentages: CaCO3 87%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1%, and fly ash 5.5%.

[0044] The preparation methods of Examples 2-3 are the same as those of Example 1, and their performance is also similar.

[0045] Comparative Example 1

[0046] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 40g KMnO, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0047] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0048] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0049] Comparative Example 2

[0050] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 0.55g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0051] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0052] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0053] Comparative Example 3

[0054] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.65g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0055] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0056] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0057] Comparative Example 4

[0058] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 2.2g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0059] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0060] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0061] Comparative Example 5

[0062] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 30g KClO, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0063] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0064] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0065] Comparative Example 6

[0066] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 2.2g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0067] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0068] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0069] Comparative Example 7

[0070] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 3.3g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0071] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0072] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0073] Comparative Example 8

[0074] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 4.4g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0075] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0076] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0077] Comparative Example 9

[0078] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 0g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0079] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0080] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0081] Comparative Example 10

[0082] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 1.1g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0083] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0084] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0085] Comparative Example 11

[0086] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 2.2g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0087] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0088] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0089] Comparative Example 12

[0090] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 3.3g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0091] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0092] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0093] Comparative Example 13

[0094] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 30g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0095] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0096] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0097] Comparative Example 14

[0098] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 1.1g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0099] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0100] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0101] Comparative Example 15

[0102] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 1.65g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0103] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0104] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0105] Comparative Example 16

[0106] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 2.2g Fe2O3, 3.30g (CH3COO)2Ca, and 6.05g fly ash.

[0107] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0108] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0109] Comparative Example 17

[0110] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 0g (CH3COO)2Ca, and 6.05g fly ash.

[0111] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0112] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0113] Comparative Example 18

[0114] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 1.1g (CH3COO)2Ca, and 6.05g fly ash.

[0115] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0116] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0117] Comparative Example 19

[0118] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 2.2g (CH3COO)2Ca, and 6.05g fly ash.

[0119] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0120] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0121] Comparative Example 20

[0122] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 4.4g (CH3COO)2Ca, and 6.05g fly ash.

[0123] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0124] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0125] Comparative Example 21

[0126] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 0g fly ash.

[0127] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0128] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0129] Comparative Example 22

[0130] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 3.03g fly ash.

[0131] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0132] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0133] Comparative Example 23

[0134] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 9.08g fly ash.

[0135] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0136] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0137] Comparative Example 24

[0138] A desulfurizing agent for coal-fired flue gas is made from the following raw materials: 93.5g CaCO3, 1.1g KMnO4, 1.1g KClO3, 4.4g NaCl, 0.55g Fe2O3, 3.30g (CH3COO)2Ca, and 12.1g fly ash.

[0139] The preparation method of the above-mentioned coal-fired flue gas desulfurization agent includes the following steps:

[0140] Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

[0141] This invention uses high-quality porous calcium carbonate with a particle size of 200 mesh, and the calcium spraying temperature is controlled between 850-900 degrees Celsius. The calcium-to-sulfur ratio is 1:2, and certain additives such as potassium permanganate, potassium chlorate, sodium chloride, ferric oxide, calcium acetate, and fly ash are added (Example 1, Comparative Examples 1-24). Each time, 5 kg of coal is used, along with 5% water and 110 g of additives. The mixture is stirred evenly and then added to the furnace for combustion. At high temperature, a sampling tube is placed in the flue to extract flue gas containing harmful gases. Data is measured. To ensure the accuracy of the experiment and minimize errors, each set of data is measured three times in parallel, and the average value is taken. A curve is plotted based on the results. This invention uses a ZR-3100 flue gas comprehensive analyzer to determine the sulfur content in the flue gas. The results are shown in Tables 2-7.

[0142] Table 2. Effect of potassium permanganate content on desulfurization efficiency

[0143]

[0144] Table 3. Effect of potassium chlorate content on desulfurization efficiency

[0145]

[0146] Table 4. Effect of sodium chloride content on desulfurization efficiency

[0147]

[0148] Table 5. Effect of ferric oxide content on desulfurization efficiency

[0149]

[0150] Table 6. Effect of calcium acetate content on desulfurization efficiency

[0151]

[0152] Table 7. Effect of fly ash content on desulfurization efficiency

[0153]

[0154] From the data in Table 2, we can obtain Figure 1 : Average SO2 emissions (mg / m³) with potassium permanganate content as the X-axis. 3 (Y-axis) shows that the desulfurization effect is best when the potassium permanganate content is 1.1g in 110g of additives.

[0155] From the data in Table 3, we can obtain Figure 2 : Average SO2 emissions (mg / m³) with potassium chlorate content as the X-axis. 3 (Y-axis) shows that the desulfurization effect is best when the potassium chlorate content is 1.1g in 110g of additives.

[0156] From the data in Table 4, we can obtain Figure 3 : Average SO2 emissions (mg / m³) with sodium chloride content as the X-axis. 3 (Y-axis) shows that, in 110g of additives, the desulfurization effect is best when the sodium chloride content is 4.4g.

[0157] From the data in Table 5, we can obtain Figure 4 : Average SO2 emissions (mg / m³) with ferric oxide content as the X-axis. 3 (Y-axis) indicates that the desulfurization effect is best when the content of ferric oxide is 0.55g in 110g of additives.

[0158] From the data in Table 6, we can obtain Figure 5: Average SO2 emissions (mg / m³) with calcium acetate content as the X-axis. 3 (Y-axis) shows that, in 110g of additives, the desulfurization effect is best when the potassium chlorate content is 3.30g.

[0159] From the data in Table 7, we can obtain Figure 6 : Average SO2 emissions (mg / m³) with fly ash content as the X-axis. 3 (Y-axis) shows that, in 110g of additives, the desulfurization effect is best when the potassium chlorate content is 6.05g.

[0160] The data and charts above show that the X-axis represents the additive content, and the Y-axis represents the desulfurization value. The optimal desulfurization effect is achieved when using 5 kg of coal, adding 5% water, and using 110 g of additives with the following contents: potassium permanganate 1%, potassium chlorate 1%, sodium chloride 4%, ferric oxide 0.5%, calcium acetate 3%, and fly ash 5.5%. This can reduce SO2 emissions in flue gas to below 200 mg / m³. 3 It meets the national emission standards for low-tonnage boilers in western provinces (300mg / m³). 3 Potassium permanganate and potassium chlorate act as oxygen-supplying agents, decomposing to release oxygen at high temperatures. This allows sulfur dioxide in the coal seam to react with oxygen to form sulfur trioxide, which then reacts with calcium oxide in the furnace to form calcium sulfate, increasing the sulfur fixation rate. They also act as combustion aids, accelerating heat release and promoting complete combustion. Sodium chloride and ferric oxide act as catalysts, primarily promoting the reaction between sulfur dioxide and minerals in the coal, facilitating combustion. Additionally, they lower the activation energy required for coal combustion. Sodium chloride increases the conversion rate of the sulfur-fixing agent, while ferric oxide inhibits the decomposition of calcium sulfate during calcium-based sulfur fixation, thus increasing the sulfur fixation rate. Calcium acetate and fly ash act as calcium-based desulfurizing agents. The alkaline slurry formed by the dissolution of calcium oxide and other alkaline substances in fly ash in water facilitates desulfurization. All these additives play a crucial role in the desulfurization effect.

[0161] The desulfurization effect increases with the increase of additive dosage. This is mainly because the additive enhances the activity of the sulfur-fixing agent, thereby loosening it, increasing the porosity of the calcium-based sulfur-fixing agent, and forming more and larger gaps, which is conducive to the gas-solid reaction and thus improves the desulfurization effect. On the other hand, the presence of metal ions in the additive promotes the increase of sulfur fixation rate through ionic effects during the sulfur fixation reaction. However, studies have shown that when the additive content exceeds a certain value, the desulfurization effect begins to slowly decrease with the increase of additive dosage. This is partly because excessive additives block the SO2 diffusion channels, affecting the surface chemical reaction between the sulfur-fixing agent and SO2. Another reason is that the added additives have the effect of lowering the ash melting point; when added in excess, surface sintering occurs, thus reducing the desulfurization effect of the sulfur-fixing agent.

[0162] It should be noted that the formula provided by this invention can also be used for denitrification, but due to objective conditions, denitrification will not be described in this article.

[0163] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A coal-fired flue gas desulfurization agent, characterized in that, It is made from the following raw materials in the indicated weight percentages: CaCO3 85-90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1-3%, and fly ash 2-5.5%.

2. The desulfurizing agent for coal-fired flue gas according to claim 1, characterized in that, It is made from the following raw materials in the indicated weight percentages: CaCO3 85%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 3%, and fly ash 5.5%.

3. The desulfurizing agent for coal-fired flue gas according to claim 1, characterized in that, The particle size of CaCO3 is 200 mesh.

4. The coal-fired flue gas desulfurizer according to claim 1, characterized in that, The calcium-to-sulfur ratio is 1:

2.

5. The method for preparing the coal-fired flue gas desulfurizer according to any one of claims 1-4, characterized in that, Includes the following steps: The following raw materials were weighed and weighed to prepare the product: CaCO3 85-90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1-3%, and fly ash 2-5.5%. Grind CaCO3, adding KMnO4, KClO3, NaCl, Fe2O3, (CH3COO)2Ca and fly ash during the grinding process to obtain a mixed powder, which is the desulfurizing agent for coal-fired flue gas; the powder has a mesh size of 200 mesh.

6. A method for desulfurizing coal-fired flue gas, characterized in that, Includes the following steps: The desulfurizing agent for coal-fired flue gas is sprayed onto the combustion furnace using the in-furnace calcium injection method. At 800-900℃, the desulfurizing agent solidifies the sulfur elements in the furnace, reducing the SO2 content discharged from the flue. The desulfurizing agent for coal-fired flue gas is made from the following raw materials in the indicated mass percentages: CaCO3 85-90%, KMnO 41%, KClO 31%, NaCl 4%, Fe2O3 0.5%, (CH3COO)2Ca 1-3%, and fly ash 2-5.5%.

7. The method for desulfurizing coal-fired flue gas according to claim 6, characterized in that, The combustion furnace is a chain grate furnace.

8. The method for desulfurizing coal-fired flue gas according to claim 6, characterized in that, The SO2 content emitted from the flue gas duct was measured using a ZR-3100 flue gas comprehensive analyzer.

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