Odor Removal Activated Carbon Design Method
1. Odor causing gases
There are many odor causing gases in our environment. Here are some examples.
| Nuisance Gas Properties | ||||
| Gas Classification | Acid Gas | Alkaline Gas | ||
| Gas Formula | NH3 | (CH3)3N | H2S | CH3SH |
| Gas Names | ammonia | trimethylamine | hydrogen sulfide | methylcaptan |
| Molecular Weight | 17.03 | 59.11 | 32.08 | 48.11 |
| Boiling Point | -33.4 | 3.5 | -61.8 | 7.6 |
| Barely Noticeable Lev1 (ppb) | 100 | 0.1 | 0.5 | 0.1 |
| Identifiable Lev2 (ppb) | 600 | 1 | 6 | 0.7 |
| Smells Lev3 (ppb) | 1000 | 5 | 20 | 2 |
| Strong Odor Lev 4(ppb) | 2000 | 20 | 60 | 4 |
|
Nuisance Gas Properties |
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| Gas Classification | Neutral Gases | |||
| Gas Formula | (CH3)2S | (CH3)2S2 | CH3CHO | C6H5CH:CH |
| Gas Names | methylsulfide | dimethylsulfide | aetaldehyde | styrene |
| Molecular Weight | 62.13 | 94.19 | 44.05 | 104.14 |
| Boiling Point | 38C | 117C | 20.2C | 145C |
| Barely Noticeable Lv1 (ppb) | 0.1 | 0.3 | 2 | 30 |
| Identifiable Lv2 (ppb) | 2 | 3 | 10 | 200 |
| Smells Lv3 (ppb) | 10 | 9 | 50 | 400 |
| Strong Odor Lv4(ppb) | 40 | 30 | 100 | 800 |
2. Specially treated pellet Carbon for various gas removal applications
| Pellet Carbon For Nuisance Gas: General Specifications | ||||||
| Target Gases | Acid Gas | Alkaline Gas | Neutral Gases | |||
| Pellet Designator | 4G-H | 4T-B | 4GG | 4SA | 4T-C | 4T-F |
| Size 4mm Dia x 6mm L | 4/6 | 4/6 | 4/6 | 4/6 | 4/6 | 4/6 |
| Specific Gravity (g/ml) | 0.40-0.45 | 0.50-0.60 | 0.43-0.48 | 0.48-0.55 | 0.48-0.56 | 0.43-0.48 |
| Hardness (%) | >95 | >95 | >95 | >95 | >95 | >95 |
| Drying Weight Loss (%) | <5 | <30 | <5 | <5 | <20 | <10 |
| Benzene Adsorption (%) | >38 | --- | >33 | >25 | >30 | >20 |
| Primary Effective Gases | H2S,CH3SH | NH3,(CH3)3N | C6H5CH:CH | (CH3)2S,(CH3)2S2 | (CH3)2S,(CH3)2S2 | CH3CHO,CH2O |
| Secondary Effective Gases | C6H5CH:CH | H2S,CH3SH | C6H5CH:CH | C6H5CH:CH | ||
| (CH3)2S2 | CH3SH | |||||
Pressure Drop Consideration
Equilibrium Adsorption Consideration
Design Steps for one gas
(1) Odor Element Generation - A (kg)
A= (C*M*Q*L/(22,400*1,000)) * 273/(273+T)
C: Gas Concentration (ml/M3=ppm), M: molecular weight (g/mol), Q: flow rate (m3/hr) L: life (hr), T: Temperature (C), 22,400: 1 mol gas amount (ml/mol), 1000: conversion from kg to g (g/kg)
(2)Activated carbon amount needed - B (kg)
B= W1+W2
W1: Activated carbon needed from the equilibrium chart.
W1= (A*100)/X X(%): The equilibrium adsorption % on each odor.
W2: Activated carbon needed from contact time calculations
W2=LV*CT*SQ/SG
LV: Linear Velocity (m/sec) CT: Contact Time (sec) 0.3-0.8 sec. SQ: Flow cross section area (m2) SG: Specific gravity of activated carbon used
Note: Please use an appropriate safety factor after computations: i.e. 1.3
The equilibrium gas adsorption amount can be expressed in the following formula within a certain range of gas concentration. Xi=A*Ci**B where
Xi=Gas adsorption amount (g) for 100g of activated carbon carbon Ci=Gas concentration (ppm) A & B are an experimental constant (see below)
| Gas Classification | Acid Gas | Alkaline Gas | ||
| Gas | NH3 | (CH3)3N | H2S | CH3SH |
| Gas Names | anmonia | trimethylamine | hydrogen sulfide | methylcaptan |
| Formula | Xi(g)=8.3xCi**0.063 | Xi(g)=11.0xCi**0.079 | Xi(g)=34.0xCi**0.126 | Xi(g)=8.0xCi**0.129 :4T-C |
| Formula | Xi(g)=2.8xCi**0.355 :4G-H | |||
| Gas Classification | Neutral Gases | |||
| Gas | (CH3)2S | (CH3)2S2 | CH3CHO | C6H5CH:CH |
| Gas Names | methylsulfide | dimethylsulfide | aetaldehyde | styrene |
| Formula | Xi(g)=3.4xCi**0.091 :4T-C | Xi(g)=8.8xCi**0.145 | Xi(g)=6.0xCi**0.086 | Xi(g)=21.4xCi**0.150 |
| Formula | Xi(g)=1.1xCi**0.310 :4SA |
If a granular carbon bed is preferred in stead of pellet carbon, please see:
If a sheet carbon is preferred in stead of pellet carbon, please see :