Apparatus and method for catalytic oxidation of magnesium sulfite, and cobalt nitrate/ZSM-5 molecular sieve catalyst and preparation method thereof

A technology of magnesium sulfite oxide and ZSM-5, which is applied in the direction of molecular sieve catalysts, catalyst activation/preparation, metal/metal oxide/metal hydroxide catalysts, etc., can solve the problem of large evaporation energy consumption, large oxidation area, Problems such as heavy metal ion pollution, operating costs, etc.

Active Publication Date: 2019-11-08
NORTH CHINA ELECTRIC POWER UNIV (BAODING) +1
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  • Abstract
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  • Application Information

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Problems solved by technology

However, magnesium desulfurization will produce a large amount of magnesium sulfite by-products, which need to be oxidized to magnesium sulfate before recycling
[0003] The existing recovery of magnesium sulfite mainly adopts the method of non-catalytic forced oxidation concentration-evaporation crystallized magnesium sulfate. Due to the low oxidation rate, the oxidation occupies a large area, the energy consumption of evaporation is large, and the recovery cost is high, and it cannot be continuous Production
It has also been reported that a homogeneous catalytic oxidation method has been tried, that is, the transition metal ions are directly added to the magnesium sulfite slurry for catalytic oxidation, but this method has the problems of difficult recovery of transition metal ions, pollution of heavy metal ions and high operating costs.

Method used

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  • Apparatus and method for catalytic oxidation of magnesium sulfite, and cobalt nitrate/ZSM-5 molecular sieve catalyst and preparation method thereof

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preparation example Construction

[0049] The invention provides the preparation method of above-mentioned cobalt nitrate / ZSM-5 molecular sieve catalyst, comprises the following steps:

[0050] (1) ZSM-5 molecular sieve and cobalt nitrate solution are mixed for ion exchange to obtain a catalyst precursor;

[0051] (2) Calcining the catalyst precursor to obtain a cobalt nitrate / ZSM-5 molecular sieve catalyst.

[0052] In the invention, ZSM-5 molecular sieve is mixed with cobalt nitrate solution for ion exchange to obtain catalyst precursor. In the present invention, there is no special requirement on the source of the ZSM-5 molecular sieve, and conventional commercially available ZSM-5 molecular sieves in the field can be used. In the present invention, the molar concentration of the cobalt nitrate solution is preferably 0.1 to 0.3 mol / L, more preferably 0.15 to 0.2 mol / L; the volume ratio of the ZSM-5 molecular sieve to the cobalt nitrate solution is preferably 2 ~10 g: 100 mL, more preferably 4 ~ 8 g: 100 mL...

Embodiment 1

[0062] Preparation of cobalt nitrate / ZSM-5 molecular sieve catalyst:

[0063] (1) Add 4g of ZSM-5 molecular sieve to 100mL of 0.15mol / L cobalt nitrate solution, perform ion exchange under 80°C water bath condition, the exchange time is 24h, and repeat the ion exchange after replacing the cobalt nitrate solution;

[0064] (2) The above solution is centrifuged at a speed of 4500r / min, the supernatant is discarded, and washed three times with deionized water;

[0065] (3) The solid after centrifugal cleaning was dried in a drying oven at 80°C for 6h, calcined in a muffle furnace at 300°C for 2h, and the heating rate was 2°C / min to obtain a cobalt nitrate / ZSM-5 molecular sieve catalyst, the mass of cobalt nitrate in the catalyst 5% load;

[0066] Use gained catalyst to catalyze magnesium sulfite oxidation, concrete method is as follows:

[0067] Take 200mL of deionized water in the reactor, add magnesium sulfite and catalyst into the reactor, feed air, and start timing at the sa...

Embodiment 2

[0072] Use the device of catalytic oxidation magnesium sulfite provided by the present invention to carry out catalytic oxidation to the magnesium sulfite solid of magnesium method desulfurization power plant, concrete method is as follows:

[0073] (1) the magnesium sulfite raw material enters the preparation box and mixes with water, and obtains the magnesium sulfite slurry through stirring, wherein the mass concentration of the magnesium sulfite slurry is 45%;

[0074] (2) The magnesium sulfite slurry enters the reaction box to contact with the catalyst, at 200m 3 Carry out oxidation reaction under / h aeration condition, obtain magnesium sulfate slurry, wherein the temperature of oxidation reaction is 45 ℃, and catalyzer is the cobalt nitrate / ZSM-5 molecular sieve catalyst that embodiment 1 gains, its quality and the volume of magnesium sulfate slurry The ratio is 40g: 1L;

[0075] (3) the magnesium sulfate slurry enters the evaporator and is concentrated to 60% of the ori...

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Abstract

The invention provides an apparatus and method for catalytic oxidation of magnesium sulfite, and a cobalt nitrate / ZSM-5 molecular sieve catalyst and a preparation method thereof, belonging to the technical field of flue gas desulphurization. According to the invention, a preparation box is utilized to pretreat a magnesium sulfite raw material; a reaction box is used for performing a catalytic oxidation reaction; an evaporator is employed for concentrating magnesium sulfate slurry obtained after catalytic oxidation; a cooling and crystallization box is used for cooling and crystallizing the concentrated slurry; an obtained solid is discharged directly as a product; and remaining slurry is returned to the evaporator for further concentration. The apparatus provided by the invention is a continuous reaction device, can realize continuous catalytic oxidation of magnesium sulfite, has high production efficiency and low cost, and produces no waste residues or waste liquid in the whole catalytic oxidation process; the cobalt nitrate / ZSM-5 molecular sieve catalyst used in the apparatus of the invention is a solid catalyst, has high catalytic rate and long service life, and can avoid contamination of an oxidation product by a homogeneous catalyst.

Description

technical field [0001] The invention relates to the technical field of flue gas desulfurization, in particular to a device and method for catalyzing the oxidation of magnesium sulfite, a cobalt nitrate / ZSM-5 molecular sieve catalyst and a preparation method thereof. Background technique [0002] Magnesium desulfurization technology has the advantages of good desulfurization effect and low operation and maintenance costs, and is currently widely used in coal-fired boilers. However, magnesium desulfurization will produce a large amount of magnesium sulfite as a by-product, which needs to be oxidized to magnesium sulfate before it can be recycled. [0003] The existing recovery of magnesium sulfite mainly adopts the method of non-catalytic forced oxidation concentration-evaporation crystallized magnesium sulfate. Due to the low oxidation rate, the oxidation occupies a large area, the energy consumption of evaporation is large, and the recovery cost is high, and it cannot be con...

Claims

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Application Information

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IPC IPC(8): B01J29/46B01J8/02
CPCB01J29/46B01J8/02C01F5/40B01D9/0004B01J23/75B01J37/30
Inventor 汪黎东卢肃马永亮
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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