Composite material of 4A zeolite loaded bicarbonate and application of composite material as explosion suppressant

Abstract

The invention provides a 4A zeolite loaded bicarbonate composite material and application thereof as an explosion suppressant, a preparation method of the 4A zeolite loaded bicarbonate composite material comprises the following steps: adding 4A zeolite into deionized water to prepare a turbid liquid, and then adding bicarbonate powder; fully stirring and standing; then evaporating and crystallizing the mixture; after the evaporative crystallization is finished, taking out a solid sample, grinding, and screening to obtain the 4A zeolite loaded bicarbonate composite material. According to the 4A zeolite loaded bicarbonate composite material, the anti-caking performance and the fire extinguishing and explosion suppression performance can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of preparation of functional powder materials, and in particular relates to a 4A zeolite-loaded bicarbonate composite material and an application thereof as an explosion suppressant. Background Art

[0002] The main components of BC dry powder fire extinguishing agents and explosion suppressants widely used on the market are NaHCO3 or KHCO3. The particle size of this type of substance is mainly around 50μm. Experiments have shown that explosion suppressants with smaller particle sizes show better explosion suppression performance due to faster decomposition speed. However, in actual production, the explosion suppressants are not made finer, mainly because when the powder particles are small enough, strong van der Waals forces will be generated between them, causing NaHCO3 or KHCO3 powders to agglomerate, and small-particle dry powders are more likely to agglomerate in a high humidity environment. This seriously affects the suppression efficiency and long-term storage of bicarbonate dry powder.

[0003] In order to solve the above-mentioned agglomeration problem, the current commercial dry powder fire extinguishing agent needs to strictly control the humidity and temperature of the storage environment during storage to prevent the powder from absorbing moisture and agglomerating; and the dry powder fire extinguisher is shaken before use to ensure that the dry powder in the tank is loose to prevent clogging. In addition, commercial BC dry powder fire extinguishing agents will add an appropriate amount of anti-caking agents to the bicarbonate powder, such as silica gel, talcum powder, silicon dioxide and other substances. These anti-caking agents can absorb moisture or increase the fluidity between particles, thereby reducing the agglomeration between particles. However, the simple addition of these substances will increase the overall amount of suppression medium and reduce the suppression efficiency. Summary of the invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a composite material of 4A zeolite loaded with bicarbonate and its application as an explosion suppressant.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] In a first aspect, the present invention provides a 4A zeolite-loaded bicarbonate composite material, the preparation method of which comprises the following steps:

[0007] First, 4A zeolite is added to deionized water to prepare a suspension, and then bicarbonate powder is added; the mixture is stirred thoroughly and allowed to stand; then the mixture is evaporated and crystallized; after the evaporation and crystallization, a solid sample is taken out and ground and sieved to obtain a composite material of 4A zeolite loaded with bicarbonate.

[0008] Preferably, the bicarbonate is KHCO3 or NaHCO3.

[0009] Preferably, the mass ratio of the bicarbonate to the 4A zeolite is (1-3):1.

[0010] Preferably, the solid-liquid ratio of the suspension is 1:(2-5).

[0011] Preferably, the particle size of the sieved 4A zeolite-loaded bicarbonate composite material is no greater than 200 meshes.

[0012] Preferably, the evaporation crystallization conditions are: placing the product in a constant temperature box at 60-100°C for constant temperature evaporation crystallization.

[0013] In a second aspect, the present invention further provides a method for preparing the above-mentioned 4A zeolite-loaded bicarbonate composite material, comprising the following steps:

[0014] 4A zeolite is added to deionized water to prepare a suspension, and then bicarbonate powder is added; the mixture is fully stirred and allowed to stand; the mixture is then evaporated and crystallized; after the evaporation and crystallization, a solid sample is taken out and ground and sieved to obtain a composite material of 4A zeolite loaded with bicarbonate.

[0015] In a third aspect, the present invention also provides the use of the above-mentioned 4A zeolite-loaded bicarbonate composite material in the preparation of explosion suppression.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The 4A zeolite-loaded bicarbonate composite material of the present invention can significantly improve the anti-caking performance and fire extinguishing and explosion suppression performance of bicarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a process flow chart for implementing the 4A zeolite loaded with bicarbonate.

[0019] Figure 2 The SEM spectrum of KHCO3 used in Example 1 of the present invention;

[0020] Figure 3 The SEM spectrum of NaHCO used in Example 1 of the present invention;

[0021] Figure 4 The particle size distribution diagram of KHCO3 and NaHCO3 used in Example 1 of the present invention;

[0022] Figure 5 is the SEM spectrum of 4A zeolite in Example 1 of the present invention;

[0023] Figure 6 The SEM spectrum of Zeolite-NaHCO3 prepared in Example 1 of the present invention;

[0024] Figure 7 This is the SEM spectrum of Zeolite-KHCO3 prepared in Example 1 of the present invention;

[0025] Figure 8 The particle size distribution diagram of Zeolite-NaHCO3 and Zeolite-KHCO3 prepared in Example 1 of the present invention;

[0026] Fig. 9 The experimental apparatus used in Test Example 1;

[0027] Fig.10 H under different KHCO3 inertization ratios f，max and V f，max change;

[0028] Fig.11 The H under different Zeolite-KHCO3 inertization ratios f，max and V f，max change;

[0029] Fig.12 The 75% relative humidity constant humidity device used in Test Example 2;

[0030] Fig.13 The agglomeration rate of bicarbonate after storage for different time periods before and after treatment. DETAILED DESCRIPTION

[0031] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0032] The present invention will be described in detail below with reference to the embodiments.

[0033] Example 1

[0034] The operation steps of loading bicarbonate on 4A zeolite are as follows Figure 1 First, 4A zeolite was added to deionized water to prepare two suspensions at a solid-liquid ratio of 1:5, and then KHCO3 powder and NaHCO3 powder of equal mass to the zeolite were added respectively; after being fully stirred, the mixture was allowed to stand for 12 hours; then the two mixtures were placed in a thermostat at 60°C for evaporation and crystallization; after 12 hours, the solid samples were taken out, fully ground with a grinding mortar, and sieved with a 200-mesh sieve, thereby obtaining 4A zeolite-loaded KHCO3 (Zeolite-NaHCO3) and 4A zeolite-loaded KHCO3 (Zeolite-KHCO3).

[0035] The particle size distribution and microscopic morphology of KHCO3, NaHCO3 and zeolite before treatment and Zeolite-NaHCO3 and Zeolite-KHCO3 after treatment were compared using a laser particle size distribution analyzer and a scanning electron microscope. The SEM images of KHCO3 and NaHCO3 used in this case are shown in Figure 1. Figure 2 and Figure 3 , the particle size distribution is Figure 4 It can be found that the median particle size (D 50 ) were 46.67 μm and 51.03 μm respectively. The particle shapes of the two particles were irregular, the boundaries between the particles were unclear, and there was obvious agglomeration, which is an important factor leading to the agglomeration of bicarbonate. The SEM spectrum of the 4A zeolite used in this example is shown in Figure 5 , mainly presenting a tetrahedral structure.

[0036] Zeolite-NaHCO3 and Zeolite-KHCO3 were obtained by Example 1, and their SEM spectra are shown in Figure 6 and Figure 7 , the particle size distribution is Figure 8 The median particle sizes of Zeolite-NaHCO3 and Zeolite-KHCO3 are 4.701μm and 4.193μm respectively. Compared with KHCO3 and NaHCO3, the particle sizes are significantly reduced. Figure 6 and Figure 7 ,After the composite treatment, a large number of tiny KHCO3 and NaHCO3 particles were attached to the tetrahedral structure of 4A zeolite, with clear boundaries between the particles, relatively uniform particle size distribution, and no obvious agglomeration phenomenon was observed.

[0037] Example 2

[0038] The operation steps of loading bicarbonate on 4A zeolite are as follows Figure 1 First, 4A zeolite was added to deionized water to prepare a suspension at a solid-liquid ratio of 1:2, and then KHCO3 powder was added at a mass ratio of 2:1 to zeolite; after sufficient stirring, the mixture was allowed to stand for 12 hours; then the mixture was placed in a thermostat at 60°C for evaporation and crystallization; after 12 hours, the solid sample was taken out, fully ground with a grinding mortar, and sieved with a 200-mesh sieve to obtain 4A zeolite-loaded KHCO3 (Zeolite-NaHCO3).

[0039] Example 3

[0040] The operation steps of loading bicarbonate on 4A zeolite are as follows Figure 1First, 4A zeolite was added to deionized water to prepare a suspension at a solid-liquid ratio of 1:3, and then NaHCO3 powder was added at a mass ratio of 3:1 to zeolite; after sufficient stirring, the mixture was allowed to stand for 12 hours; then the mixture was placed in a thermostat at 60°C for evaporation and crystallization; after 12 hours, the solid sample was taken out, fully ground with a grinding mortar, and sieved with a 200-mesh sieve to obtain 4A zeolite-loaded KHCO3 (Zeolite-KHCO3).

[0041] Test Example 1

[0042] In order to demonstrate the enhancement of explosion suppression performance, the Zeolite-KHCO3 prepared in Example 1 was subjected to a sintering reaction using household edible wheat starch as explosive dust. Fig. 9 The experimental device shown in the figure tests the inhibitory performance of Zeolite-KHCO3 on the explosion of 0.8g wheat starch. The device mainly consists of a 150cm vertical pipeline, a high-speed camera, an electric ignition device, a gas distribution system and a dust disperser. Before the experiment, the dust sample is evenly placed on the disperser, and the gas distribution system is pressurized to 500kPa. After the experiment starts, under the action of compressed air and disperser, the dust sample is evenly dispersed into the vertical pipeline. After an ignition delay time of 60ms, the ignition electrode (electrode spacing 3mm) generates 500mJ of energy to ignite the dust cloud, and the flame begins to propagate in the pipeline, while the high-speed camera (resolution 1080P, frame rate 480fps) records the flame propagation process. By analyzing the flame propagation image and calculating the height difference between the flame array and the ignition electrode, real-time flame height and flame propagation speed data are obtained.

[0043] In this case, the inertization ratio is used to describe the relative amount of inhibitor added in the experiment, and α represents the mass ratio of the inhibitor to the explosive dust. KHCO3 with different inertization ratios [0.008g (α = 0.01) ~ 0.048g (α = 0.06)] was uniformly mixed with 0.8g wheat starch. Fig. 9 The device shown in the figure studies the efficiency of KHCO3 in inhibiting the flame propagation of wheat starch. The flame propagation process is recorded by a high-speed camera. Fig.10 The maximum flame height (H) after adding KHCO3 with different inerting ratios is shown. f，max ) and the maximum flame propagation speed (V f，max ) changes.

[0044] Zeolite-KHCO3 [0.008 g (α = 0.01) ~ 0.04 g (α = 0.05)] after composite treatment with different inertization ratios was uniformly mixed with 0.8 g wheat starch to carry out flame propagation inhibition experiments. Fig.11 The results show that the H f，max and V f，max changes.

[0045] from Fig.10 It can be found that when the KHCO3 inerting ratio increases to 0.06, the combustion of wheat starch is completely inhibited, and the flame height and flame propagation speed are both 0. Fig.11 In the experiment, the inerting ratio of Zeolite-KHCO3 only needs to be 0.05 before wheat starch can be ignited and the flame is completely suppressed. Therefore, 4A zeolite-loaded KHCO3 (Zeolite-KHCO3) optimizes the explosion suppression efficiency of KHCO3.

[0046] Test Example 2

[0047] In order to demonstrate the improvement of the anti-caking performance of bicarbonate powder by the present invention, Zeolite-NaHCO3 and Zeolite-KHCO3 were obtained in Example 1. Fig.12 The experimental apparatus shown is in a constant humidity environment, and the anti-caking properties of Zeolite-NaHCO3 and Zeolite-KHCO3 are evaluated using a sieving method. Fig.12 The experimental equipment shown is mainly composed of a constant temperature box and a dryer containing a saturated NaCl solution. The saturated NaCl solution can maintain the relative humidity in the dryer at 75% (75% RH) at 60°C. Spread the sample with a mass of m in a petri dish, place it in a dryer and use a constant temperature box to maintain the temperature at 60°C. Take it out after a certain period of time and dry it in an oven at 60°C for 6 hours. The dried sample is fully sieved through a 16-mesh sample sieve (the sieve hole is 1.16mm). The sieve aperture experimental test can ensure that the non-agglomerated sample passes smoothly without destroying the agglomerated sample. The sample that does not pass through the 16-mesh sample sieve is defined as an agglomerated sample. Use an analytical balance to weigh the sample mass m1 before sieving and the mass m2 after sieving, and calculate the agglomeration rate of the sample according to the following formula:

[0048]

[0049] Fig.13 The agglomeration rates of the four samples before and after treatment after being stored in a high humidity environment for different periods of time are shown. As the exposure time to the high humidity environment increases, the agglomeration rates of the four samples gradually increase. Among them, the agglomeration phenomenon of KHCO3 is the most obvious, and the agglomeration rate reaches 96% after 12 hours of storage. NaHCO3 also shows obvious agglomeration after exposure to high humidity, and the agglomeration rate reaches 72% after 12 hours of storage.

[0050] Compared with bicarbonate, the anti-caking performance of Zeolite-KHCO3 and Zeolite-NaHCO3 is significantly improved. After 6 hours of storage in a 76RH environment, Zeolite-KHCO3 basically did not clump, and after 12 hours, only about 8% of the samples had clumps. For Zeolite-NaHCO3, the anti-caking performance is even more significant, and the agglomeration rate is still less than 1% after 12 hours of exposure.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite material of 4A zeolite loaded with bicarbonate, characterized in that: The preparation method thereof comprises the following steps: 4A zeolite is added to deionized water to prepare a suspension, and then bicarbonate powder is added; the mixture is fully stirred and allowed to stand; the mixture is then evaporated and crystallized; after the evaporation and crystallization, a solid sample is taken out and ground and sieved to obtain a composite material of 4A zeolite loaded with bicarbonate.

2. The 4A zeolite-loaded bicarbonate composite material according to claim 1, characterized in that: The bicarbonate is KHCO3 or NaHCO3.

3. The 4A zeolite-loaded bicarbonate composite material according to claim 1, characterized in that: The mass ratio of the bicarbonate to the 4A zeolite is (1-3):

1.

4. The 4A zeolite-loaded bicarbonate composite material according to claim 1, characterized in that: The solid-to-liquid ratio of the suspension is 1:(2-5).

5. The 4A zeolite-loaded bicarbonate composite material according to claim 1, characterized in that: The particle size of the sieved 4A zeolite-loaded bicarbonate composite material is no greater than 200 meshes.

6. The 4A zeolite-loaded bicarbonate composite material according to claim 1, characterized in that: The conditions for evaporation crystallization are: placing in a constant temperature box at 60-100°C for constant temperature evaporation crystallization.

7. The method for preparing the composite material of 4A zeolite loaded with bicarbonate according to any one of claims 1 to 6, characterized in that: The steps include: 4A zeolite is added to deionized water to prepare a suspension, and then bicarbonate powder is added; the mixture is fully stirred and allowed to stand; the mixture is then evaporated and crystallized; after the evaporation and crystallization, a solid sample is taken out and ground and sieved to obtain a composite material of 4A zeolite loaded with bicarbonate.

8. Use of the composite material of 4A zeolite loaded with bicarbonate according to any one of claims 1 to 6 in the preparation of explosion suppressants.

Images