Biomass boiler fuel pretreatment method, pretreatment device and flue gas denitrification method

A biomass boiler and boiler flue gas technology, applied in separation methods, chemical instruments and methods, coke ovens, etc., can solve problems such as boiler efficiency decline, potential safety hazards, and bio-oil being difficult to achieve flue gas denitrification effect. Boiler slag discharge to ensure the effect of heating efficiency

Active Publication Date: 2019-10-29
SHANDONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The inventor found that the biomass pyrolysis temperature is too high, on the one hand, it affects the heat exchange of the heating surface at the boiler tail, thereby reducing the boiler efficiency by about 5%
On the second aspect, the high temperature of flue gas recirculation places too high requirements on the biomass pretreatment room in the recirculation pipeline, which is likely to cause safety hazards
In the third aspect, if the temperature is higher than 700°C, it belongs to flash pyrolysis. Under very high reaction rate and extremely short gas phase residence period, mainly gas products are generated, and the yield is as high as 80%. At this time, the charcoal obtained by pyrolysis Less, difficult to provide carbon source for boiler combustion
[0006] When the temperature of biomass pyrolysis is low, such as 500-600°C, in this temperature range, it is mainly used to increase the yield of bio-oil, and the yield of bio-oil can reach 80%, and it is difficult for bio-oil to play a good role. Flue gas denitrification effect
If biomass is thermally decomposed at 150-400°C under anaerobic conditions, the content of charcoal can be increased to the maximum, but the residence period is too long, generally takes several hours to several days, and the main product is charcoal, so it is difficult to use pyrolysis gas to the boiler flue gas denitrification reaction

Method used

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  • Biomass boiler fuel pretreatment method, pretreatment device and flue gas denitrification method

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preparation example Construction

[0063] The preparation method of molecular sieve refers to the following steps:

[0064] Weigh a certain amount of roasted MCM-41 molecular sieve, add a certain amount of toluene and aminopropyltrimethoxysilane, and reflux for 8 hours. After the product is centrifuged, it is first washed with methanol, and then washed with distilled water until there is no unreacted Silicone and solvent toluene. Dry at 100-120°C to obtain organic functionalized MCM-41 molecular sieve.

[0065] The functionalized MCM-41 molecular sieve is mixed with a mixture of copper nitrate and iron nitrate at a certain concentration, and the molar ratio of copper nitrate and iron nitrate is 1:3-6. Stir at room temperature for 10 hours, centrifuge, and ultrasonically clean with distilled water for 3-5 times until there are no copper ions and iron ions in the solution. The cleaned molecular sieve is dried and calcined to obtain the required catalyst.

[0066] The molecular sieve can also be other kinds of ...

Embodiment 1

[0070] The sawdust is crushed, and the particle size after crushing is less than 0.7cm;

[0071] Spray the catalyst in the crushed sawdust, mix well, the catalyst is a molecular sieve loaded with copper oxide and iron oxide, the molar ratio of copper oxide and iron oxide is 1:2, and the molecular sieve is MCM-41 molecular sieve;

[0072] The mass ratio of sawdust to catalyst is 1000:2, and the mass of copper oxide and iron oxide loaded in each gram of molecular sieve is 0.05g.

[0073] Extract the flue gas at 350°C from the boiler, pass it into the biomass material mixed with the catalyst, and pyrolyze the wood chips. The pyrolysis time is 10 minutes, and the pyrolysis gas and charcoal are obtained. The carbon content in the charcoal is 90%. There is basically no tar in the solution gas.

[0074] After the pyrolysis gas is washed with water, it is mixed with the secondary air at a volume ratio of 1:2, and passed into the boiler to reduce the nitrogen oxides in the boiler flue...

Embodiment 2

[0076] Crushing the corn stalks, the particle size after crushing is less than 0.1cm;

[0077] Spray the catalyst in the crushed corn stalks, mix well, the catalyst is a molecular sieve loaded with copper oxide and iron oxide, the molar ratio of copper oxide and iron oxide is 1:2, and the molecular sieve is MCM-41 molecular sieve;

[0078] The mass ratio of corn stalks to the catalyst is 1000:2, and the mass of copper oxide and iron oxide loaded in each gram of molecular sieve is 0.2g.

[0079] Extract the flue gas at 300°C from the boiler, pass it into the corn stalks mixed with the catalyst, and pyrolyze the corn stalks for 20 minutes to obtain pyrolysis gas and charcoal. The content of carbon in the charcoal is 85%. There is basically no tar in the solution gas.

[0080] After the pyrolysis gas is washed with water, it is mixed with the secondary air at a volume ratio of 1:1.8 and passed into the boiler to reduce the nitrogen oxides in the boiler flue gas to nitrogen to re...

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Abstract

The invention discloses a biomass boiler fuel pretreatment method, a pretreatment device and a flue gas denitrification method. The pretreatment method comprises the steps of crushing biomass; spraying a catalyst to the crushed biomass, and mixing well; extracting flue gas with 300-350 DEG C from a boiler, introducing to a biomass material which a catalyst is mixed in, and pyrolyzing the biomass material to obtain pyrolytic gas and carbon, wherein the catalyst is a molecular sieve loaded with copper oxide and iron oxide in a molar ratio of 1:(2-3). The flue gas with 400-500 DEG C extracted from the boiler is mixed with air to treat biomass; low-level heat is utilized; therefore, heating efficiency of the boiler is guaranteed. When the treatment temperature for biomass is low, a pretreatment chamber to pretreat the biomass has low requirements, and the pretreatment process has better safety and reliability.

Description

technical field [0001] The invention belongs to the technical field of biomass energy utilization and coal-fired industrial boiler flue gas denitrification, and in particular relates to a biomass boiler fuel pretreatment method, a pretreatment device and a boiler flue gas denitrification method. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] Biomass direct combustion power generation is currently the most important form of biomass utilization, but during the operation of biomass boilers, the slagging and corrosion problems caused by alkali metals and chlorine elements will seriously affect the economical, safe and stable operation of the units. Chlorine is the core of th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/86B01D53/56C10B57/08C10B53/00
Inventor 任霄汉李玉昆
Owner SHANDONG UNIV
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