A method for preventing caking of sodium bicarbonate for flue gas purification

Abstract

The invention discloses an anti-caking method for sodium bicarbonate for flue gas purification, which improves the phenomenon of moisture absorption, caking and clogging during use by adding suitable chemical substances to sodium bicarbonate, and at the same time improves the use efficiency of sodium bicarbonate in flue gas treatment reaction and reduces its consumption. An anti-caking method for sodium bicarbonate for flue gas purification, adding chemical raw materials mixed in proportion to sodium bicarbonate powder and mixing them evenly, including by weight: 33-48% of sodium aluminosilicate, 40-55% of calcium phosphate, 5-10% of propylene glycol, and 1%-2% of amide wax.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to an anti-caking method of sodium bicarbonate for flue gas purification. Background Art

[0002] Since sodium bicarbonate has the advantages of high efficiency, low investment and simple process in the flue gas purification process, it is used more and more in flue gas purification projects. At present, the sodium bicarbonate produced and sold in China is 60-120 mesh powder with a water content of ≤0.2%. The crystal shapes are mostly irregular shapes such as flakes and needles. It is a chemical raw material that is very easy to absorb moisture and agglomerate. During transportation, storage and use, the production process is often stopped due to agglomeration and blockage, which has a great impact on the operation of continuous production equipment. In the process of flue gas purification, sodium bicarbonate needs to be stored in large quantities and for a long time, and requires a long pipeline for transportation. The agglomeration and blockage of sodium bicarbonate have a serious impact on the flue gas purification production process.

[0003] In order to improve the use of sodium bicarbonate in the flue gas purification process and improve its moisture absorption and agglomeration properties, it is necessary to modify it so that it will not be blocked during storage and transportation, and enhance its fluidity to meet production needs.

[0004] Mixing different forms of substances into different materials can greatly change the physical and chemical properties of the materials. We add a small amount of chemical raw materials into the sodium bicarbonate powder in different proportions. Without affecting its use effect, it can greatly improve its moisture absorption and agglomeration properties, increase its fluidity, and at the same time, to a certain extent improve its reaction efficiency in the flue gas purification process and save usage. Summary of the invention

[0005] The object of the present invention is to provide an anti-caking method based on sodium bicarbonate for flue gas purification, by adding suitable chemical substances into sodium bicarbonate to change its physical and chemical properties so that its moisture absorption, agglomeration and clogging phenomena can be improved during use, and at the same time, the use efficiency of sodium bicarbonate in flue gas treatment reactions can be improved and its consumption can be reduced.

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

[0007] A method for preventing sodium bicarbonate from caking for flue gas purification comprises adding an anti-caking agent to sodium bicarbonate powder and mixing the mixture uniformly. The anti-caking agent comprises, by weight, 33-48% of sodium aluminosilicate, 40-55% of calcium phosphate, 5-10% of propylene glycol, and 1%-2% of amide wax.

[0008] As a preferred technical solution, the amount of the anti-caking agent added to the sodium bicarbonate is: 1.5%-4% by weight of the sodium bicarbonate powder.

[0009] As a preferred technical solution, the particle size of the anti-caking agent is 500-700 mesh.

[0010] As a preferred technical solution, the density of the anti-caking agent is 0.7~0.85g / cm³.

[0011] As a preferred technical solution, the crystal structure of sodium bicarbonate is columnar or granular.

[0012] As a preferred technical solution, the particle size of the anti-caking agent is 600 mesh.

[0013] As a preferred technical solution, the weight ratio of the anti-caking agent added to the sodium bicarbonate is: 2% by weight of the sodium bicarbonate powder.

[0014] As a preferred technical solution, the anti-caking agent includes, by weight, 40% sodium aluminosilicate, 48% calcium phosphate, 10% propylene glycol, and 2% amide wax.

[0015] In the present invention, sodium bicarbonate is modified by adding a baking soda anti-caking agent, so that its moisture-proof and anti-caking properties are enhanced. Among them, the substances calcium phosphate and sodium aluminosilicate have water-fixing effects, which are combined with the moisture between the crystal grains to be stable, and reduce the effect of free migration of water in the sodium bicarbonate. Propylene glycol is used as a dispersant to separate the crystals from each other without adhesion. Amide wax is used as a hydrophobic agent to prevent moisture in the air from contacting the crystals and getting damp. The comprehensive use of these four substances in a certain proportion makes the baking soda powder of 60 to 120 meshes have excellent moisture-proof and anti-caking properties, and still has good fluidity even if it is naturally stored for more than 60 days in the summer with high temperature and high humidity.

[0016] The present invention selects calcium phosphate and sodium aluminosilicate in the subsequent flue gas treatment process, which shows the effect of improving the reaction efficiency of sodium bicarbonate and saving the amount of sodium bicarbonate. In the flue gas purification process, baking soda is first decomposed into sodium carbonate, carbon dioxide and water. The acidic gas in the flue gas reacts with sodium carbonate. Calcium phosphate and sodium aluminosilicate can combine a part of water during the reaction process to improve the reaction efficiency of sodium carbonate and acidic gas. Calcium phosphate has a certain catalyst effect, which reduces the reaction potential energy of sodium carbonate and acidic gas, making it easier for acidic gas to react chemically with sodium carbonate and improve its use efficiency. Therefore, this embodiment selects calcium phosphate and sodium aluminosilicate for use simultaneously to achieve the best effect. DETAILED DESCRIPTION

[0017] The purpose of the present invention is to change the physical and chemical properties of baking soda that it is easy to absorb moisture and form lumps, and to provide an anti-caking method for sodium bicarbonate for flue gas purification. The present invention is further described in detail below in conjunction with embodiments.

[0018] A method for preventing caking of sodium bicarbonate for flue gas purification (hereinafter referred to as anti-caking agent) comprises the following steps:

[0019] An anti-caking agent is added to the sodium bicarbonate powder and mixed evenly. The anti-caking agent includes, by weight, 33-48% of sodium aluminosilicate, 40-55% of calcium phosphate, 5-10% of propylene glycol, and 1%-2% of amide wax; the weight ratio of the anti-caking agent added to the sodium bicarbonate is: 1.5%-4%; the particle size of the anti-caking agent is 500-700 mesh; and the density of the anti-caking agent is 0.7-0.85 g / cm³.

[0020] The actual effect of anti-caking agent is tested by the fluidity index "angle of repose" under powder gravity. The smaller the angle of repose, the smaller the friction and the better the fluidity. It is generally believed that the angle of repose θ≤40 o The powder has good fluidity.

[0021] Experimental Example 1: Anticaking agent effect test

[0022] Baking soda particle size: 80 mesh (d90)

[0023] Moisture content: 0.2%

[0024] Test conditions: 1000ml beaker placed naturally open

[0025] Temperature conditions: 25-35℃

[0026] Humidity conditions: 60-80%.

[0027] Test indicators: Test the angle of repose under gravity conditions of 0 days, 5 days, 15 days, 40 days and 80 days respectively.

[0028] The following fluidity test table does not provide data because the angle of repose data could no longer be tested.

[0029] Test 1: Comparison between blank sample and standard sample

[0030]

[0031] From this we can see that after adding anti-caking agent, the placement time of baking soda under the same conditions has little effect on its fluidity.

[0032] Test 2: Effect of anticaking agent addition on fluidity

[0033]

[0034] When the anti-caking agent addition amount reaches 2%, increasing the addition amount does not significantly improve the fluidity of baking soda, so 2% is determined as the optimal anti-caking agent addition ratio.

[0035] Test 3: Effect of anticaking agent particle size on fluidity

[0036]

[0037] When the particle size of the anti-caking agent reaches 500 mesh (d90) or above, the increase in the particle size does not significantly change the fluidity of baking soda. When the particle size is lower than 500 mesh (d90), the fluidity of baking soda becomes significantly worse. Since the larger the mesh size, the higher the cost, the anti-caking agent can be 600 mesh.

[0038] Test 4: Effect of different components on fluidity

[0039]

[0040] The use of a single substance is not effective in improving the fluidity of baking soda.

[0041] Test 5: Effect of Sodium Aluminosilicate on Fluidity

[0042]

[0043] When the sodium aluminosilicate content is around 40%, baking soda exhibits the best fluidity.

[0044] Test 6: Effect of calcium phosphate on fluidity

[0045]

[0046] Baking soda exhibits the best fluidity around 48% calcium phosphate.

[0047] Test 7: Effect of Propylene Glycol on Fluidity

[0048]

[0049] Baking soda exhibits the best fluidity when the propylene glycol content is around 10%.

[0050] Test 8: Effect of Amide Wax on Fluidity

[0051]

[0052] When the amide wax content is around 2%, baking soda exhibits the best fluidity.

[0053] Experimental Example 2: Deacidification efficiency test of sodium bicarbonate with anti-caking agent added

[0054] (1) Groups: Different anti-caking agent embodiments were prepared. Each anti-caking agent embodiment of the same component was divided into 6 parts, namely groups A to F. Groups A to F were added to sodium bicarbonate at a weight ratio of 1%, 1.5%, 2%, 3%, 4%, and 4.5%, respectively.

[0055] (2) Experimental conditions: Sodium bicarbonate with anti-caking agent is used in the flue gas purification process to remove 95% of the acid gas in the flue gas. The flue gas volume is 95000Nm3 / h standard.

[0056] (3) Test index: The amount of sodium bicarbonate used when the flue gas treatment meets the standard.

[0057] The anti-caking agent components of different embodiments are shown in Table 1 of Experiment 1 above.

[0058] Test 9: Effect of anti-caking agent on deacidification efficiency of baking soda

[0059]

[0060] It can be seen from this table that when the anti-caking agent addition amount is above 2%, the consumption of sodium bicarbonate does not change much when the flue gas treatment standard is met.

[0061] It can be seen from test tables 1 to 8 that the anti-caking agent includes by weight: 40% sodium aluminosilicate, 48% calcium phosphate, 10% propylene glycol, and 2% amide wax; the weight ratio of the anti-caking agent added to sodium bicarbonate is: 2%; the particle size of the anti-caking agent is 600 mesh; when the density of the anti-caking agent is 0.72g / cm³, the effect is best and reaches the peak value.

[0062] Different substances will show different physical and chemical properties when mixed. We select these substances and mix them according to different mechanisms and proportions, and process them into different particle sizes for use in proprietary industries (flue gas deacidification). Baking soda has a significant effect in preventing moisture and caking, and increasing its fluidity during storage and use.

[0063] It is worth noting that, based on the premise of the above-mentioned structural design, in order to solve the same technical problem, even if some non-substantial changes or modifications are made to the present invention, the essence of the technical solution adopted is still the same as that of the present invention, so it should also be within the scope of protection of the present invention.

Claims

1. A method for preventing caking of sodium bicarbonate for flue gas purification, characterized in that: An anti-caking agent is added to the sodium bicarbonate powder and mixed evenly. The anti-caking agent comprises, by weight, 33-48% of sodium aluminosilicate, 40-55% of calcium phosphate, 5-10% of propylene glycol, and 1%-2% of amide wax.

2. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 1, characterized in that: The amount of anti-caking agent added to sodium bicarbonate is: 1.5%-4% by weight of sodium bicarbonate powder.

3. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 1, characterized in that: The particle size of the anti-caking agent is 500~700 mesh.

4. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 1, characterized in that: The density of anti-caking agent is 0.7~0.85g / cm³.

5. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 1, characterized in that: The crystal structure of sodium bicarbonate is columnar or granular.

6. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 3, characterized in that: The particle size of the anticaking agent is 600 mesh.

7. The anti-caking method of sodium bicarbonate for flue gas purification according to claim 2, characterized in that: The weight ratio of the anti-caking agent added to the sodium bicarbonate is: 2% by weight of the sodium bicarbonate powder.

8. A method for preventing caking of sodium bicarbonate for flue gas purification according to any one of claims 1 to 7, characterized in that: The anti-caking agent comprises, by weight, 40% of sodium aluminosilicate, 48% of calcium phosphate, 10% of propylene glycol, and 2% of amide wax.

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