Flow Measurements .ppt

7/27/2019 Flow Measurements .ppt

1/19


2/19

Gas Quantities Of Dry Pyroprocess

Cement factory, wi th nom inal prod uct ion o f :

1 m il l ion to n/year.

The ki ln w i l l be fired w ith l iqu id fuel oi l ( mazou t ),

and the fuel consumption is 950 kcal /kg cl inker. the

lower calor i f ic value of the oi l is 9600 kcal/kg fuel

Calcu late the fol low ing :

1- Air quantity required for combustion.

2- Smoke gas quantity in both kiln, preheater.

Example:


3/19

Solution :

1 Million ton/year = 3300ton cl inker / dayFuel Consumption = 950 kcal/kg cl ink er

Lower calorific value of mazout = 9,600 cal/kg fuel

The production = 3,300 *1,000/ 24 = 137,500 kg clin ker /hrTotal heat consumption = 137,500 *950 =130,625,000 kcal/hr

Theamount of m azout = 130,625,000/ 9600= 1,3606.8 kg Oil/h rAir requi red for combus t ion = :

Lo = [ (9600 -1115)/808 ] =10.5 Nm3/kg o il


4/19

where :

Lo =the required combust ion air.

Hu =lower heat value ( 9600 Kcal/kg fo r fuel oil )

Lo =[ (9600-1115)/ 808 ] =10.5 Nm3/Kg oil.

1.08 x10.5=11.34 Nm3/Kg fuel.

That means per hour: 11.34 x13606.8 =154,301 Nm3air / hr.

Excess air for safe com bust ion is requ ired say 8%


5/19

The calc inations process asks for the smoke or exi t gas quant i ty

Vo= [(1.25 Hu -3025)/808] Nm3/K g o il (fuel).

where

Vo =The produced smoke gas volume.

Vo =[ (1.25 x9600 -3025) /808]=11.11 Nm3/Kg fuel.

=11.11 x13606.8 =151,139.9 Nm3/ hr. ------------ ( 1 )


6/19

Unfortun ately the cement pro cess is a chemical , physical

process & by the decl ination the bound s CO2wil l be vo lat iled

There fore CaCo3= 40 + 12 + 3 x 16 = 40 + 12 + 48 = 100 .

The decalcined carbonate is cal led Quick Lime or burnt

l ime and i ts formula is : CaO = 40 + 16 = 56

The atom weight o f the elements in calc ium carbonate CaCo3

Calcium Ca = 40 Carbon C = 12 Oxygen O = 16

From 100carbonate remain 100 - 56 = 44are volat i led and

escape joint ly the smoke o r exi t gas.


7/19

False Air : (Kiln)

Assuming 0.5 %O2at the ki ln up stream.

O2%21 O2 %

The false air =0.5

21 0.5= =2.5 %

To tal false air

= [ (2.5/100) x151139.9] =3778.5 Nm3/ hr.------------- ( 2 )

Assum ing c alc inat ions in ki ln is 15 % ,

and L .O.I ( Lo ss In Ignit ion ) 35 % Kg Co2 Kg c link er.

Total volati led Co2in ki ln

= (35 %/ 1.977) x15% x137500 Kg clin ker / h r.

= 3651.4 Nm3Co2/ hr. --------------------------------------- ( 3 )


8/19

We have 35 - 40 %firing in kiln . from the total firing,

and 60

65 %firing in preheater from the total firing.

Ki ln smoke gases

= [(40/100) x151139.9]=60456 Nm3/ hr. ---------------------( 4 )

Total ki ln gases = ( 2 ) + ( 3 ) + ( 4 )

= 3778.5 +3651.4 +60456

67885.9 Nm3/ hr.


9/19

If we have by -pass 20 %

The by -pass gases = [ 67885.9 x( 20 / 100 ) ]

13577 Nm3/ hr.

Total ki ln gases excluding by pass gases

= 67885.9 - 13577 = 54308.9 Nm3/ hr. ----------- ( 5 )

Total smoke gases in preheater

=[ ( 60/100 ) x151139.9] =90684 Nm3 / hr. ------- ( 6 )

Assum ing calc inat ions in preheater is 85 %and L .O.I = 35 %


10/19

False Air : (Preheater)

Assum ing O2con tent after preheater is 5 %

O2%-221 O2 %

The false air =0.5

21 0.5= =2.5 %

Total volati led Co2in p reheater =

= [ ( 35%/1.977 ) x85% x137500 ] kg c linker / hr

= 20691 Nm3/ hr. --------------------------------- ( 7 )


11/19

Total smoke gases in preheater + CO2=

90684 +20691 =111375 Nm3/h r

Total false air in preheater :

=[ ( ( 5 -2 )/ ( 21 -5 ) )/( 90684 +20691 ) ]

=[ ( 3/16 ) x11375 ] 20883 Nm3 / hr. -------- ( 8 )


12/19

Total gases after preheater

=5 +6 +7 +8

=54308.9 +90684 +20691 +20883

=186,567 Nm3/ hr.


13/19


14/19


15/19

Determination of the Gas Conditions in the main duct

Static Pressure as Under pressure


16/19

Static Pressure as Over pressure


17/19

Selection of asuitable

Samplingposition


18/19

Determinationof

measuring

points

in Circular

ducts


19/19

Prandtl tube

Documents

Flow Measurements .ppt