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Method for recycling abandoned SCR catalyst

A SCR catalyst and resource-recycling technology, applied in the directions of heterogeneous catalyst chemical elements, chemical instruments and methods, physical/chemical process catalysts, etc. The effect of cleaning strength, reducing production cost and prolonging cleaning time

Inactive Publication Date: 2017-03-15
XIAN THERMAL POWER RES INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this prevention method has the following problems: ① the consumption of water is large, and the waste liquid produced is difficult to handle; ② the regenerated catalyst needs to maintain a certain mechanical strength so that it can be installed and used again
For the recycling method of spent catalysts, the following problems need to be solved: ①Screening and cleaning of spent catalysts. It is difficult to use spent catalysts directly, and pretreatment is required
② How to realize the uniform mixing of waste catalyst and fresh titanium dioxide, the material properties of the regenerated powder made of waste catalyst and fresh titanium dioxide are very different, if the powder is not mixed uniformly, it is easy to cause problems such as catalyst cracking
However, there are also the following problems in the actual application process. After the ground titanium dioxide is mixed with metatitanic acid and calcined, it will affect the growth of metatitanic acid particles.
The regenerated catalyst particles are calcined at high temperature again, which will further reduce their specific surface area, which is not conducive to the improvement of the catalytic efficiency of the catalyst.

Method used

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  • Method for recycling abandoned SCR catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Take the deactivated SCR catalyst replaced by a domestic power plant, and screen out the specific surface area greater than 35m 2 / g module, the surface loads are mainly CaO, Al by XRF analysis 2 o 3 , MgO, SiO 2 and SO 3 etc., cut it into small pieces of 5cm*5cm*8cm. Use compressed air to blow off the dust on the surface, and then remove the load on the surface through bubbling vibration cleaning and chemical cleaning, and then rinse with clean water. According to the XRF test, the content of Fe is 0.038%, the content of Mg is 0.029%, the content of Ca is 0.050%, the content of K is 0.11%, and the content of Na is 0.19%.

[0046] The catalyst after cleaning is sent into (3) Raymond mill through (1) Raymond mill entrance, is ground into the powder of D (90)=4.7um, after (2) Raymond mill outlet, it is sent into a mixing tank. The mass of the ground catalyst powder added in the stirring tank is 100kg, and then through (4) the titanium dioxide adding port, add fresh ...

Embodiment 2

[0049] Take 100kg of leftover material produced during the production process of SCR catalyst, and its specific surface area is 65.7m after testing 2 / g, cut it into small pieces of 6cm*6cm*10cm, crush and grind to obtain 100kg of catalyst powder, mix evenly with titanium dioxide slurry containing 900kg of titanium dioxide, and then pass through a plate and frame filter to remove excess water to obtain titanium dioxide The filter cake is then flash-dried through a flash evaporator. The inlet temperature of the flash evaporator is 200°C, the outlet temperature is 95°C, the residence time of the material is 6s, and the air flow rate is 4m / s. The SCR catalyst with a vanadium content of 0.8% is obtained through the processes of compounding, pre-extruding, aging, extruding, drying and calcining. The denitrification performance test bench is used to compare the performance of the catalyst obtained by this method with that of conventional commercial catalysts. After laboratory simul...

Embodiment 3

[0051] Take the waste SCR catalyst replaced by the power plant, and screen out the specific surface area greater than 35m 2 100kg per gram, cut into small pieces of 5cm*5cm*8cm, washed with alkali, surfactant and water for 1.5 hours. After crushing and grinding, the catalyst powder is obtained, which is evenly mixed with the titanium dioxide slurry containing 900kg of titanium dioxide, and then the excess water is removed through a plate and frame filter to obtain a titanium dioxide filter cake, which is then flashed and dried by a flash machine. The temperature is 200°C, the outlet temperature is 95°C, the material residence time is 6s, and the air velocity is 4m / s. The SCR catalyst with a vanadium content of 0.8% is obtained through the processes of compounding, pre-extruding, aging, extruding, drying and calcining. The denitrification performance test bench is used to compare the performance of the catalyst obtained by this method with that of conventional commercial catal...

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Abstract

The invention belongs to the technical field of boiler environmental protection and specifically relates to a method for recycling an abandoned SCR catalyst. The method for recycling the abandoned SCR catalyst comprises the following steps: screening out the abandoned SCR catalyst meeting the recycling standard; using a chemical agent for cleaning and removing impurities; grinding into recycled powder in a certain fineness; uniformly mixing and stirring the recycled powder and fresh titanium dioxide at a certain ratio in a stirring tank; adopting a filter for removing the redundant water, thereby obtaining a titanium dioxide filter cake; adopting an expansion drying machine for drying the filter cake, thereby obtaining the mixed powder meeting the commercial use requirement. The indexes of a catalyst prepared from the mixed powder all meet the performance requirements of the commercial SCR catalyst; the environment is protected while the use of the raw material in the production process is reduced; the method has certain economic benefit and environmental benefit.

Description

technical field [0001] The invention belongs to the technical field of boiler environmental protection, and in particular relates to a resource recycling method for waste SCR catalysts. Background technique [0002] Nitrogen oxides (NO x ) is a highly toxic pollutant that endangers biological health and destroys the atmospheric environment. Its main hazards are: ① destroying the respiratory system of humans and animals; ② producing toxic effects on plant cells and tissues; ③ forming acid rain and acid fog One of the main reasons; ④ can react with hydrocarbons to produce photochemical smog; ⑤ can make O 3 Decomposition occurs, destroying the atmospheric ozone layer. The main source of nitrogen oxides is the combustion of fossil fuels. Among many flue gas denitrification technologies, selective catalytic reduction (SCR) is currently one of the most widely used, mature and effective flue gas denitrification technologies. SCR catalyst is the core of selective catalytic reduc...

Claims

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Application Information

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IPC IPC(8): B01J23/30B01D53/86B01D53/56
CPCB01J23/002B01D53/8628B01D2258/0283B01J23/30B01J2523/00B01J2523/47B01J2523/55B01J2523/69
Inventor 吴国勋罗奖合张强李建玺王凯尹琢然郭利静
Owner XIAN THERMAL POWER RES INST CO LTD