Beer Yeast Powder Spin Flash Centrifugal Spray Dryer

1,Designed Parameter:

⑴,Material name:Beer yeast

⑵,Inlet Air Temperature:160℃；

⑶,Outlet Air Temperature:80℃；

(4),Solid-liquid content:10%；

(5),Capacity:300㎏/h；

⑹,Feed rate:more than 98%；

⑺,Final product moisture:5%；

⑻,Dusting method:Dust removal of two stage cyclone dust collector +spray dust elimination;

⑼,Operate mode:non-stop operation

⑽,Drying medium:The filtered air；

⑾,Heat source: direct burning type natural gas hot blast stove.

2,Characteristic of material:

Solid content of raw yeast liquor:10%,The output is about 210 tons a month.

Equipment Design

1,Determination of process calculation parameters:

⑴ Material parameter:

Feed water content : 　ω_１＝90％, Product moisture content: ω_２＝5％；

Feed temperature:　　　θ_１＝20℃, θ₂=60℃

Output of drying tower: Ｗ_产＝300㎏／ｈ.

⑵ Air parameter :

Ambient temperature:　　　　　　　　 ｔ_０＝20℃,

Air moisture:　　　　　　　　ｄ_０＝0.01㎏water/㎏ dry air,

Hot air inlet temperature of drying tower:　　　　ｔ_１= 160℃

Hot air inlet moisture content:　　　　　　ｄ_１= 0.01㎏ water/㎏dry air

Exhaust temperature of drying tower :　　　　　ｔ_２ =8 0℃,

2,Material balance

Take off the water :

Ｗwater＝Ｗcapacity×(ω_１-ω_２) /(1-ω₁)

＝300×(90%-5%)/(1-90%)

＝2550Ｋｇ／ｈ

Feed quantity of raw material liquid:

W_进=W_水+W_产=2850kg/h

3,Heat balance:

⑴ Evaporation heat required:

　Ｑ_１＝Ｗ_水×595+Ｗ_水×(0.45×ｔ_２－１×θ₁)

＝2550×595+2550×(0.45×80－１×20)

＝155.8×10^４Kcal／ｈ

⑵ The product heats up the heat needed:

　Ｑ_２＝Ｗ_产×〔Ｃｓ×(１－ω_２)＋１×ω_２〕×(θ_２－θ_１)

　　　＝300×〔0.4×(１－0.05)＋１×0.05〕×(60－20)

　　　＝0.516×10^４Kcal／ｈ

⑶ External heat loss of drying tower:

　Ｑ_３ ＝0.1×(Ｑ_１＋Ｑ_２)

＝0.1×(155.8＋0.516)×10^４

＝15.63×10^４Kcal／ｈ

Checking computations:Dry heat loss control in the periphery 60～100Ｋcal／Ｋｇ water,Now:15.63×10^４/2550＝61.3Ｋcal／Ｋｇwater,In the control range.

⑷ The hot air flow required for drying:(Consider the amount of air leakage by 10%)

　Ｇ＝(Ｑ_１＋Ｑ_２＋Ｑ_３)/［ｉ_１－ｉ_２＇－０.１×０.２４×(t₂-ｔ_０)］

　ｉ_１－ｉ_２＇＝(0.24＋0.45×ｄ_１)×(ｔ_１－ｔ_２)

＝(0.24＋0.45×0.01)×(160－80)　

＝19.56Ｋcal／Ｋｇ

Ｇ ＝1.1×(155.8＋0.516＋15.63)×10⁴/ (19.56－0.1×0.24×(80－20 )),

　 ＝94896.85Ｋｇ／ｈ convert volume flow as 73563Nm³/h

⑸ Required heat for drying:

　Ｑ＝Ｇ×(ｉ_１－ｉ_０)

　ｉ_１－ｉ₀＝〔(0.24＋0.45×ｄ_１)×ｔ_１＋595×ｄ_１〕－〔(0.24＋0.45×ｄ_０)×ｔ_０＋595×ｄ_０〕

　　　　　＝〔(0.24＋0.45×0.01)×160＋595×0.01〕－〔(0.24＋0.45×0.01)×20＋595×0.01〕

　　　　　＝34.23Kcal／Ｋｇ

　Ｑ＝94896.85×34.23＝324.8×10^４Kcal／ｈ

⑹ ,The drying tower exhaust moisture content calculation:

　ｄ_２＝ｄ_１＋Ｗ_水/Ｇ

　　　＝0.01＋2550/94896.85＝0.03687Ｋｇwater/Ｋｇdry air

　Check the air humidity diagram:The wet bulb temperature corresponding to the exhaust temperature and moisture content isｔ_ｗ２＝46℃,则ｔ_２－ｔ_ｗ２＝80－46＝34℃,Can ensure the cyclone separator does not dew.

4,Calculation of spray tower:

⑴The selection of atomizer:

Preliminary selection of Lpg3000 type high-speed centrifugal atomizer,The diameter of the atomizing disc is 0.20m, and the maximum speed is 13000 R / min.

⑵Jet distance calculation:

　 Jet radius:Ｒ＝３.４６ｄ^０.３×Ｇ^０.２５×ｎ^{－０.１６}

　As before list:ｄ＝0.20ｍ,Ｇ＝2850Ｋｇ／ｈ,

　　　　ｎ＝12500ｒ／ｍｉｎ

　 ∴　Ｒ＝3.46×(0.20)^０.３×(2850)^０.２５×(12500)^{－０.１６}

　　　　 ＝3.46×0.617×7.3×0.221

　　　　 ＝3.448ｍ

⑶Inner diameter of spray tower:

The inside diameter of the general spray tower isＤ_１＝(0.85～１.4)×２Ｒ

　 Get:Ｄ_１＝1.28×(２Ｒ)

　　　　　 ＝1.28×２×3.448

=8.83ｍ

　 Rounding,get Ｄ＝8.9ｍ

• Height of spray tower:

　①General spray tower straight section height is:Ｈ_１＝(0.9～1.1)Ｄ_１,

Get Ｈ_１＝1.1×Ｄ_１＝9.79ｍ

②If:Outlet diameter:Ｄ_２＝0 .30ｍ.

③Set the bottom cone angle of the cone section of the drying tower is 56°The taper height is Ｈ_２＝8.1ｍ

④Intake volute height:Ｈ₃＝1.6m

Spray tower height:Ｈ＝Ｈ_１＋Ｈ_２＋Ｈ₃＝9.79＋8.1+1.6＝19.49ｍ

⑸The average axial velocity of hot air in spray tower is checked:

In the control of axial mean velocity 0.10～0.5ｍ／ｓ.

160℃inlet air,density 0.815kg/m³, The temperature at the lower end of the straight section is 80℃,Exhaust air density 1.0kg/m³,Average hot air density is 0.9075kg/m³

　 The average air flow volume of spray tower:Ｌ＝104569ｍ^３／ｈ＝29ｍ^３／ｓ

　 Axial average velocity of hot wind:ｕ_０＝0.46ｍ／ｓ,In the control range.

⑹,The rationality of drying strength checking the size of the drying tower:

• Volume calculation of drying tower:

Cylindrical section volume:Ｖ_１＝608.74ｍ^３

Taper section volume:Ｖ₂ ＝173.56ｍ^３

　 Total Volume:V=782.3ｍ^３

Drying strength value:

　②The following formulas for calculating the drying intensity are generally provided:

　Ｅ＇＝〔(ｔ_１＋２７３)^{３.４２８７}〕/〔(ｔ_２＋２７３)^３.３４〕

　　　＝3.39Ｋｇwater/ｍ^３·ｈ

• Can take off the water:

　Ｗ_１＝Ｖ×Ｅ＝782.3×3.39＝2650Ｋｇ水／ｈ＞2550Ｋｇ水／ｈ

　　　According to the calculation of drying strength, the size of drying tower can meet the requirement of drying.

• From the rationality of checking the size of the volume heat drying tower:

　①Average log temperature difference in drying tower:

ｔ_ｍ＝〔(ｔ_１－θ_１)－(ｔ_２－θ_２)〕/ｌｎ〔(ｔ_１－θ_１)/(ｔ_２－θ_２)〕

　　＝〔(160－20)－( 80－60)〕/ｌｎ(160－20)/(80－60)〕

　　＝61.67℃

②Selection of volumetric heat transfer coefficient:

　The volumetric heat transfer coefficient for centrifugal spray drying is 30～50Ｋcal／ｍ^３·ｈ·℃,Its value is inversely related to the particle size of the product, and positively related to the axial velocity of the hot air.According to experience, small values should be taken α＝45Kcal／ｍ^３·ｈ·℃.

③The quantity of heat exchanged in a dry tower:

Ｑ_ｔ＝α×ｔ_ｍ×Ｖ

　　　=45×61.67×782.3

　　　＝217.09×10^４Kcal / ｈ＞Ｑ_１＋Ｑ_２＝156.32×10^４Kcal／ｈ

From the size check volume heat drying tower can meet the requirements of drying.

5,Heat source calculation:

The heat required for drying isＱ＝324.8×10^４Ｋcal／ｈ,Considering the low temperature in winter,As a heat source, there should be a heating allowance of 10%,The heat output of the heat source shall be Ｑ_Ｒ＝ 358×10^４Ｋcal／ｈ.

(1)Taking natural gas as heat source

If natural gas calorific value is 8500kcal/Nm³,The efficiency of direct combustion type combustion furnace for 90%,The gas consumption is:

M_燃气=468Nm³/h.

6,Calculation of cyclone dust collector:

Selection of primary cyclone dust collector:

Inlet air temperature is 80℃,Air handling rate is 94896.85m³/h,Inlet wind speed is 19m/s,select 2×CLT-2000 Cyclone dust collector.

The selection of two stage cyclone:

Inlet air temperature is 80℃,Air handling rate is 94896.85m³/h,Inlet wind speed is 19m/s,select 2×CLT-2000 Cyclone dust collector

The foam dust remover:

Inlet air temperature is 80℃,Air handling rate is 94896.85m³/hWith a diameter of 3.66 meters spray dust remover

7,Calculation of duct:

1,Inlet Air pipe,

Take inlet air speed is 18m/s,Inlet air temperature is 160℃,Inlet air rate is 116437m³/h,

Æ₁= ( V₁÷3600÷18÷0.7854)^0.5=1.523m------ getΦ1550 mm

2,Outlet air Pipe

Take outlet air speed is 16m/s,outlet air temperature is 80℃,outlet air rate is 94896.85m³/h,

Æ₂= ( V₂÷3600÷16÷0.7854)^0.5 =1.4487m----- getΦ1450 mm

8,Device parameter list:

⑴,Inside diameter of tower:Φ8900mm

⑵,The outer diameter of the tower:Φ9100mm

⑶,quantity of air required: 94896.85kg/h

(4) Inlet Air Temperature:160℃,Outlet Air Temperature:80℃.

⑸,Water evaporation:2550Kg/h .

(6),Dry powder moisture content:5%.

(7),Drying calories:324.83Million kcal/hour.

(8),First stage cyclone dust collector:2×CLT-2000,Two stage cyclone dust collector:2×CLT-2000,

The diameter of spray dust remover:3.66M

(9),blowing machine:model: 4-72-16B power:55KW speed:630R/min.

(10), induced draft fan :model:G4-73-12D power:160KW speed:1450r/min

(11),screw pump:Model:GF30-1 power:2.2kw Pressure:0.6MPa

rate of flow:3m³/h speed:940r/min

(12),atomizer:model:R-XH3t power:22KW speed:13000r/min.

9,Equipment Brief:

This design is based on user requirements, the design practice of domestic and foreign advanced experience and the factory for many years. In this design, in strict accordance with the requirements of users, and ensure the realization of the indicators. The design is based on the idea of advanced, reliable, and appropriate price concessions leeway.

The solid liquid with 10% solid content is pumped into the top of the tower by a screw pump, and the material is dispersed into even and small fog groups under the centrifugal force produced by the atomizing machine

Natural air through air filter after heated to 160 DEG C hot air drying, the hot air distributor and the upper part of the fog in the drying tower after contact with rapid cooling to 100 DEG C, and then hot material spirals, in the process of decline in air temperature decreased gradually, while the material water content decreased gradually, and ultimately meet the design requirements after the dust, exhaust gas discharged outside. This system adopts the spray volume per hour for the high-speed centrifugal atomizer 3000kg.

Dry finished powder is discharged under the drying tower and cyclone dust collector, and the exhaust gas is discharged outside after dedusting.

10,Characteristics of each system of the equipment: