Industrial production device and the production method thereof of preparation nano silicon rice hull ash
Technical field
The invention relates to preparation nanostructure SiO
2Rice hull ash, particularly a kind of nanostructure SiO
2The industrial production device of rice hull ash and production method thereof.
Background technology
About 200,000,000 tons of the rice yield in China every year accounts for 1/3 of Gross World Product, occupies first place in the world.Rice husk is the byproduct of paddy processing, accounts for paddy kernel weight 20%, 4,000 ten thousand tons of left and right sides rice husks of annual generation, and stock number is huge.A large amount of rice husk resources are underutilized, and burn mainly with the field in the rural area to be main processing mode, not only contaminate environment but also waste energy.In recent years, studies show that and contain 20% the amorphous Si O of having an appointment in the rice hull ash
2, it possesses high reactivity, is a kind of additive of material of construction, can be used as the industrial basic raw materials such as fine ceramics, photoconductive fiber and solar cell after the purification, has high added value.Therefore, not only utilized rice husk energy but also can the unformed high-purity Si O of suitability for industrialized production
2Technique be badly in need of to improve with perfect.
The patent of invention of application number 93116790.6 device of active rice husk ash " produce " has introduced the intermittent type incinerator and prepared the rice hull ash method, but there is following deficiency in this technology: 1. can't continuous-feeding, and the two step method complicated operation is unfavorable for industrialization promotion; 2. the energy of rice husk self is underutilized, and causes energy dissipation.The patent of invention of application number 200410026459.5 " the nanostructure SiO2 rice hull ash of a kind of rice husk incinerator and output thereof ", adopt closed rice husk incinerator to prepare nanostructure SiO2 rice hull ash, this patent arranges heat exchanger tube, effectively take away the heat of combusting rice hull heat release, but be subject to closed incinerator, can't continuous feeding, be difficult to solve the problems such as industrialization promotion.Publication number 102252325A " circular fluid bed of combusting rice hull " is take combustion power generation as purpose, there is no the preparation technology who relates to rice hull ash.
Summary of the invention
Purpose of the present invention is the shortcoming and defect that overcomes prior art, provide a kind of can suitability for industrialized production high-purity nm structure SiO
2The device of rice hull ash and production method thereof, and can effectively utilize rice husk to burn the heat energy that produces.
The present invention is achieved by following technical solution.
A kind of industrial production device for preparing the nano silicon rice hull ash, comprise boiler, material feeder, separator and fly-ash separator, it is characterized in that described boiler is the fluidized-bed combustion boiler of variable cross-section burner hearth, the upper furnace of this fluidized-bed combustion boiler 6 is provided with freeboard of fluidized bed 18, and the freeboard of fluidized bed diameter is 920mm; Lower furnace portion is provided with emulsion zone 17, and the emulsion zone diameter is 620mm; The burner hearth middle part is provided with variable cross-section district 19, and the vertical angle in variable cross-section district 19 is 12.5 °; The height overall of fluidized-bed combustion boiler 6 is 6m; Emulsion zone and variable cross-section district respectively arrange a cooling water jecket A 4 and cooling water jecket B 20, and the height of each cooling water jecket is 400 ~ 500mm, and two cooling water jeckets are interconnected; The foot of boiler is provided with combustion chamber 16, is provided with portfire 1, a wind entrance (2) and ash bucket A 11 below the combustion chamber 16; Combustion chamber 16 is provided with air distribution plate 15 with the junction of emulsion zone 17, one side of emulsion zone 17 is provided with screw feeder 3, be provided with secondary air entrance 5 in variable cross-section district 19, be disposed with primary cyclone 7, secondary cyclone 8, interchanger 9 and sack cleaner 10 at boiler furnace outlet; Be respectively arranged with ash bucket B 12, ash bucket C 13 and ash bucket D 14 in the bottom of primary cyclone 7, secondary cyclone 8 and sack cleaner 10.
The hearth inner lining of described fluidized-bed combustion boiler 6 is anticorrosion refractory materials.
The production method of the industrial production device of preparation nano silicon rice hull ash has following steps:
(1) dropping into particle diameters by screw feeder 3 is 0.6mm quartz sand, forms quartzy casting bed, and bed depth is 400-600mm, passes into wind one time, with the rate of heating temperature programming to 400 of 5 ℃/min ℃;
(2) the starting ignition device 1, screw feeder 3 sustainable supply rice husks; Cut off the electricity supply after lighting a fire successfully, keep temperature requiredly with the heat of combusting rice hull, regulate the secondary air feed rate guaranteeing efficiency of combustion, and with the temperature in emulsion zone 17 and variable cross-section district 19 in the circulating cooling water management stove; The operating temperature of fluidized-bed combustion boiler is 670 ℃~720 ℃, and operating air velocity is 0.9 ~ 1.4m/s, and excess air ratio is 1.16 ~ 1.21;
(3) flue gas behind the combusting rice hull carries the after-flame rice hull ash and enters primary cyclone 7, secondary cyclone 8, interchanger 9 and sack cleaner 10 by emulsion zone 17, variable cross-section district 19 and freeboard of fluidized bed 18, and rice hull ash is collected by the ash bucket A 11 of burner hearth bottom and ash bucket B 12, ash bucket C 13 and the ash bucket D 14 of two stage cyclone separator and sack cleaner bottom;
(4) hot flue gas is discharged by chimney after the processing such as desulfurization through interchanger 9 coolings again, and waste heat is recycled.
Described step (1) is to be warmed up to 400 ℃ by Electric heating.
The preferred excess air ratio of described step (2) is 1.18.
The rice hull ash that described step (3) is collected contains the unformed high-purity Si O greater than 90%
2, its form is the nanoparticle of 15~30nm.
The present invention compared with prior art, unusual effect is as follows:
The suitability for industrialized production of preparation nano silicon rice hull ash of the present invention is established device, owing to designed the variable cross-section boiler and introduced secondary air, has improved the thermo-efficiency of boiler, has solved simultaneously the limited problem of rice husk stacking volume.Owing to increased secondary cyclone, make combusting rice hull abundant, separate fully, prepare high-purity nm structure SiO
2Rice hull ash; Simultaneously, owing to adopt cooling water jecket and interchanger, can effectively control the incineration temperature of boiler, guarantee stable reaction conditions, this part of waste heat can take full advantage of simultaneously, and such as heating, supplying hot water utilizes steam-electric power etc., has saved mass energy.
Description of drawings
Fig. 1 is nanostructure SiO of the present invention
2The structural representation of rice hull ash production equipment;
Fig. 2 is the rice hull ash structure skeleton view (SEM) that adopts the present invention's preparation;
Fig. 3 is the rice hull ash polynuclear plane skeleton view (TEM) that adopts the present invention's preparation.
Reference numeral of the present invention is as follows:
Wind entrance of 1---portfire 2---
3---screw feeder 4---cooling water jecket A
5------secondary air entrance 6------fluidized-bed combustion boilers
7------primary cyclone 8---secondary cyclones
9------interchanger 10------sack cleaners
11------ash bucket A 12------ash bucket B
13------ash bucket C 14------ash bucket D
15------air distribution plate 16------combustion chambers
17------emulsion zone 18------freeboard of fluidized bed
19------variable cross-section district 20------cooling water jecket B
Embodiment
The present invention adopts conventional production unit and preparation technology, and the invention will be further described below in conjunction with accompanying drawing.
Fig. 1 is nanostructure SiO of the present invention
2The structural representation of rice hull ash production equipment.As shown in Figure 1, boiler of the present invention is the fluidized-bed combustion boiler 6 of variable cross-section burner hearth, and the upper furnace of this fluidized-bed combustion boiler 6 is provided with freeboard of fluidized bed 18, and the freeboard of fluidized bed diameter is 920mm; Lower furnace portion is provided with emulsion zone 17, and the emulsion zone diameter is 620mm; The burner hearth middle part is provided with variable cross-section district 19, and the vertical angle in variable cross-section district 19 is 12.5 °; The height overall of fluidized-bed combustion boiler 6 is 6m, and hearth inner lining is anticorrosion refractory materials; Emulsion zone and variable cross-section district respectively arrange a cooling water jecket A4 and cooling water jecket B20, and the height of each cooling water jecket is 400 ~ 500mm, and two cooling water jeckets are interconnected; The foot of boiler is provided with combustion chamber 16, is provided with portfire 1, wind entrance 2 and ash bucket A 11 below the combustion chamber 16; Combustion chamber 16 is provided with air distribution plate 15 with the junction of emulsion zone 17, one side of emulsion zone 17 is provided with screw feeder 3, be provided with secondary air entrance 5 in variable cross-section district 19, be disposed with primary cyclone 7, secondary cyclone 8, interchanger 9 and sack cleaner 10 at boiler furnace outlet; Be respectively arranged with ash bucket B 12, ash bucket C 13 and ash bucket D 14 in the bottom of primary cyclone 7, secondary cyclone 8 and sack cleaner 10.
Principle of work of the present invention is as follows: particle diameter is that the quartzy casting bed material of 0.6mm places fluidized-bed combustion boiler 6 bottoms, and height is at 400-600mm.Open wind 2 one time, by air distribution plate 15, the wind that enters burner hearth evenly distributes and makes bed reach the Micro Fluid state.During with the rate of heating temperature programming to 400 of 5 ℃/min ℃, start bottom ignition device 1, use solar oil to light a fire, send into fluidized-bed combustion boiler 6 by screw feeder 3 a small amount of rice husks of supplying with, increase air quantity (250m
3/ h) make bed reach the stabilization fluid state, when bed temperature reaches 600 ℃, increase the feeding machine feeding coal, close simultaneously bottom ignition device 1, and look the bed temperature change situation and adjust air quantity, cooling water inflow and feeding coal.The cooling water flow of adjusting feeding coal and cooling water jecket 4 makes bed temperature be stabilized in (670 ℃~720 ℃) under the suitable operating mode, drops into secondary air 5, and the actual motion wind speed is 0.9 ~ 1.4m/s.Rice husk burns at the emulsion zone fugitive constituent, discharge amount of heat, further burn to freeboard of fluidized bed with flue gas, the high-temperature flue gas that produces after the burning is successively by primary cyclone 7, secondary cyclone 8, interchanger 9 and sack cleaner 10, the rear flue gas of cooling meets discharging standards and is discharged by chimney after the processing such as desulfurization.Rice hull ash is collected in the ash bucket 11-14 of burner hearth, cyclonic separator and sack cleaner bottom.Hot flue gas is cooling off through behind the interchanger, and its heat is used for supplying with factory building and near Residential areas hot water, also can be used for hot steam or generating.
The rice hull ash of the present invention preparation after measured, its chemical constitution SiO
2Content all is higher than 90%, reaches as high as 97.1%, and the carbon residue amount is lower than 2%, and boiler combustion efficiency reaches more than 93%.X-ray diffraction pattern shows, without obvious crystalline state SiO
2Diffraction peak, this shows the SiO in the rice hull ash of preparation
2Exist with metamict.Adopt SEM technology (Fig. 2) that the rice hull ash of the present invention's preparation is carried out surfaces externally and internally and transverse section observation, show compact structure, and can observe clearly that internal surface is thin, network structure is more closely knit, the duct is abundant, high-visible, outside surface is slightly thick, structure is thicker, the duct is undeveloped; Be an interlayer between the surfaces externally and internally, interlayer is made of crisscross plate, is loose cellular, contains a large amount of holes, and the yardstick of these holes is about 10 μ m.When adopting TEM technology (Fig. 3) to carry out amplifying observation, the superfine little particle that discovery is piled up is together in a large number arranged with cellular, and particle diameter is about 15-30nm.The SiO of these nanoscales
2The hole of particle and micro-meter scale makes rice hull ash have larger specific surface area and high reactivity, is fit to special application requiring.