introduction of rto - trca.org.t 媒蓄熱式焚化技術-張豐... · pdf...

1 [email protected]
/(CTO/RTO)
Feng Tang Chang
:[email protected][email protected]
Mobile: 0933147075

2 [email protected]
/(CTO/RTO)

3 [email protected]
VOC THERMAL OXIDATION
VOC Destruction Mechanism
VOC + O2 CO2 + H2O + HCl + SO2 + N2
More precisely: (where X is any one of halogen atoms (chlorine, flurine, bromine, iodine)
CaHbNcOdSeXf+(a+e+o.25(b-f)-0.5d)O2 aCO2+0.5(b-f)H2O+fHX+eSO2+0.5cN2
Operating parameters for 99% Destruction
Temperature : 750 ~ 850
( 300 ~ 350 . with Catalyst)
Residence Time : 0.5 ~ 1 sec
Turbulence : Re > 10,000 (Re = V D / )
O2 Concentration : Over 12% at 800
(3 T)

4 [email protected]
(Thermal Oxidizer ; TO)
(Catalyst Thermal Oxidizer; CTO)
(Recuptive Thermal Oxidizer)
(Regenerative Thermal Oxidizer; RTO)

5 [email protected]
KINDS OF THERMAL OXIDIZER & COMPARISON
Direct firing RTO RCO
Systemflow
OperatingTemp.
HeatExchange
Type
ThermalRecovery
Eff.
CTO
Exhaustgas
Exhaustgas
750 ~ 850 300 ~ 350 750 ~ 850 300 ~ 350
Recuperative Recuperative Regenerative Regenerative
40 ~ 70 % 40 ~ 70 % 95 % over 95 % over
catalyst catalyst
Low Fuel Consumption
Exhaustgas
Exhaustgas

6 [email protected]
Direct thermal oxidizer

7 [email protected]
Catalyst thermal oxidizer

8 [email protected]
CTO (Catalyst Thermal Oxidizer)CTO (Catalyst Thermal Oxidizer)

9 [email protected]
Con
vers
ion
(%)
Con
vers
ion
(%)
Temperature (Temperature () @ 40,000 1/hr VHSV) @ 40,000 1/hr VHSV

10 [email protected]
(Catalyst Type)(Catalyst Type)
Lifetime: approroximate 24years

DEVELOPMENT OF RTO
2 Bed 3 Bed Rotary type
Systemflow
MotorPurge gas
PurgeAir
Untreated gas emit
when valve switch
Pressure fluctuation
Many Numbers of valve
Trouble factor
No fluctuation of
pressure
Single valve (Rotary)
Problem&
Develop-ment
Develop Prevention of untreated gas
Emission
Pressure fluctuation
when Valve switch
Develop
1st generation 2nd generation 3rd generation

MECHANISM OF 2T-RTO
Heat RecoverMedia
Heat RecoverMedia
1,400F 1,500F
From ProcessT=150F
250F
Flow Schematic
Valves switch every 90 180 secs.

MECHANISM OF 3T-RTO
Clean Process Air
Purge Air
Independent Burners
Heat Exchange Media
Solvent-Laden Process Air

MECHANISM OF RRTO
Temp.
A Bed B Bed
Heat MediaA
Outlet gas
Inlet gas
Heat MediaB
A B
Ceramic Media
A
Bed
Pyro bloc
B
Bed
Motor
Purge Air
Treated gasExhaust
gas

ROTARY TYPE RTO
Cylindrical type Rectangular type
LG Chem Kuck-Do Chem

STRUCTURE OF R-RTO
Combustion chamber
Burner
Ceramic media chamber
Rotary valve
Cylindrical type
Rectangular type

R-RTO PRINCIPLE OF OPERATING
Inlet ZONE
Outlet ZONE
: Influent
: Effluent
: Flushing
: NON-FLOW
F
NFlushing
Chamber
NON FLOW
Chamber
N
F
N
F
N
F
N
F
N
F
Straight-through
Air paths
Constant
Flow path
(No. Short
Circuit)

ADVANCED STRUCTURED BLOCK (HEAT MEDIA)
RTO--Honeycomb Monoliths

CONTROL & MONITORING PC SCREEN (Example)

Acid Gas Dewpoints (Halogenated gases and SO2/SO3 become corrosive to metals when they reach their dewpoint (liquid condensation).
Hydrochloric acid (HCl)
1000/Tdp=3.7358-0.1591 ln(PH2O)-0.0326ln(PHCl)+0.00269ln(PH2O)ln(PHCl)
Hydrofluoric acid (HF)1000/Tdp=3.8503-0.1728 ln(PH2O)-0.02398ln(PHF)+0.001135ln(PH2O)ln(PHF)
Hydrobromic acid (HBr)1000/Tdp=3.5639-0.135 ln(PH2O)-0.0398ln(PHCl)+0.00235ln(PH2O)ln(PHCl)
Sulfuric acid (H2SO4)1000/Tdp=1.7842-0.0269 ln(PH2O)-0.1029ln(PSO3)+0.0329ln(PH2O)ln(PSO3)
Where: Tdp dewpoint temperature (K)
P partial preesure (atm) (Source: Kiang. Y.H., Predicting dewpoints of acid gas, chem. Eng.,1981 & Pierce, R.R., Chem., April 11, 1977.)
Issue#1

Acid Gas Dewpoints --- example
Combustion of waste gas containing hydrogen sulfide produces com
bustion products at atmospheric with the following composition:CO2 6.03% ; H2O 11.41% ; N2 77.23% ; O2 5.31% ; SO2 0.0283% ; SO3
0.0003%,
Please caculate sulfur acid dewpoint.
============================================
Using the equation for sulfuric acid (H2SO4):
1000/Tdp=1.7842-0.0269 ln(PH2O)-0.1029ln(PSO3)+0.0329ln(PH2O)ln(PSO3)
PH2O = (11.41/100)=0.1141 atm
PSO3=(0.003/100)=0.000003 atm
Substituting into the equation:
Tdp = 400 K = 127 oC = 261 oF
Issue#1

Issue #2 (Stoichiometric air)
(1)C + O2CO212g22.4L22.4L
21:79lkg
1kg8.9m3

VOC THERMAL OXIDATIONIssue #2 (Stoichiometric air)

Issue #2 (Stoichiometric air)

Issue #3 Energy balance
LHV = HHV (N x 18.02) / MWVOC x 120
Where: LHV lower heating value (kcal/kg)HHV higher heating value (kcal/kg)N number of moles of water vapor produced per mole of VOCMWVOC molecular weight of VOC120 heat (kcal/kg) required to evaporate water at 25 oC (77oF) & 1 atm.
Usually, a value of 90% of the HHV is a close approximation to the LHV.LHV 0.9 HHV
Assume: 1 NM3/hr 600,000ppm(60% vol.)(propane;C3H8)25oC700oC28.3 x 0.6=17 NM3/hr
a.) (propane;C3H8)(Q release) = 60% x 1 NM3/hr x 1.82kgs/NM3x 12,034 kcal/kg x 0.9 =11,827 kcal/hrb.) (Q require) 17 NM3/hr x 1.293kgs/NM3 x 0.26 kcal/hr.oC x (700-25)oC = 3,858 kcal/hrc.) 11,827 kcal/hr (1.293x0.26x(700-25))= 52 NM3/hr.

Issue #3 Energy balance
Assume: 1 NM3/hr 20,000ppm(2% vol.)(propane;C3H8)25oC700oC28.3 x 0.02=0.57 NM3/hr
a.) (propane;C3H8)(Q release) = 2% x 1 NM3/hr x 1.82kgs/NM3 x 12,034 kcal/kg x 0.9=394 kcal/hrb.) 17 NM3/hr(Q require) 17 NM3/hr x 1.293kgs/NM3 x 0.26 kcal/hr.oC x (700-25)oC = 3,858 kcal/hr
(: 3,858 394 = 3,464 kcal (add 0.18 NM3 PG fuel))
(65%) Q require = 3,858 x (1-0.65) = 1,350 kcal/hr RTO (90%) Q require = 3,858 x (1-0.90) = 386 kcal/hr (Self sustain)
c.) 394 kcal/hr (1.293x0.26x(700-25))= 1.7 NM3/hr.

VOC THERMAL OXIDATIONIssue #3 Energy balance

Issue #4 /

Issue #5 Safety & others
: Flame arrestor()fresh air purge: : 25oC/min
30 mins,+65% 60 mins, 30 mins, 120 180 mins.

Flashback prevention techniques:Minimum velocity technique for flashback
prevention.Flashback flame arrestor.Flashback prevention by using air to dilute
waste stream to below LEL.Seal pot (sealing fluid) flash arrestor.
Flashback velocity (ft/s) = 0.2015 x G x DWhere G critical bounadry velocity gradient (1/s)
Dduct or pipe diameter (ft)(G value: Methane=400 ; Ethane=650 ; Propane=600 ; Propylene=700)Source from Nutcher,P.B. Maximum achievable control technology AWMA 87th Annu.,1994.

Explosive limit in air
CmHxOy + zO2 mCO2 + x/2 H2O
LEL,(%) = 0.55 (100)/(4.7m + 1.19x + 1 2.38y)UEL,(%) = 3.50 (100)/(4.76m + 1.19x + 1 2.38y)
LELmixture, (%) = 1 / (yi/LELi)UELmixture, (%) = 1 / (yi/UELi)
yi mole fraction of component i on a combusitible basis.
Example: Propane(C3H8) LEL=2.1 vol.% ; UEL=9.5 vol.%Acetone(C3H6O) LEL=2.6 vol.% ; UEL=12.8 vol.%

(Catalyst Price)(Catalyst Price)Catalyst Description: PRO-PEL 14518, SPH, 1/8"
Catalyst Type: Platinum and palladium catalyst on alumina spheres.Catalyst size: Nominal 1/8" diameter spheres
Catalyst Space Velocity: ~10,000 1/hrMinimum Catalyst Depth: 10"
Catalyst Price: $ 765 USD per cubic foot1,000 scfm 6 cubic foot $4,590USD (NT$151,470)
Catalyst Description: PRO-

introduction of rto - trca.org.t 媒蓄熱式焚化技術-張豐... · pdf...

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