Chemical Engineering January 2018 - 53

activated-carbon filters to remove
contaminants.
The rich glycol is then routed to
the glycol still column (also known
as the glycol regenerator) through
the lean/rich glycol exchanger,
where rich glycol is heated. The rich
glycol flows downward through the
glycol-regenerator stripping column
for water removal.
The lean glycol from the glycol regenerator
is transferred to the glycol
contactor by the glycol booster
and circulation pumps through
the cooler and particle filter. An air
cooler is deployed to cool down
the lean glycol before it enters into
the glycol contactor for the effective
gas-dehydration process.
Solubility of BTEX and acid gas
The amount of BTEX absorbed in
the contactor is a function of several
parameters, including the solubility
of BTEX in the glycol used, the
BTEX concentration in the feed gas,
the absorption pressure and temperature
and the glycol circulation
Call the
Solids Mixing
Ribbon & Cone Blenders
Fluidizing Mixers
Sigma Blade Mixers
(also for high-viscosity mixing)
Size Reduction
Wet & Dry Size Reduction
Steel & Ceramic Lined Mills
Jars & Jar Rolling Mills
Vacuum Drying
Dryers & Complete Systems
400
350
300
250
200
150
100
50
CO2
H2S
Benzene
Toluene
Ethylbenzene
p-Xylene
Operation condition and feed composition
Parameter
Value
Wet gas flowrate
Contactor pressure
10 million std. m3/d
80 bara
Contactor temperature 40°C
Lean glycol temperature 45°C
CO2 in inlet
H2S in inlet
8
9
10
11
Glycol circulation rate, m3/h
12
13
Benzene in inlet
Toluene in inlet
Ethylbenzene in inlet
p-Xylene in inlet
7,062 kg (9.1 mol %)
4,463 kg (7.4 mol %)
36 kg (0.026 mol %)
66.2 kg (0.04 mol %)
25.4 kg (0.01 mol %)
24.8 kg (0.01 mol %)
FIGURE 2. The solubility of contaminant species in glycol should be considered when specifying the glycol
circulation rate for a system
rate (see Figures 2 and 3). Note that
operating pressure does not have a
strong effect on aromatic absorption.
Commonly used glycols for
dehydration applications are TEG,
ethylene glycol (EG) or diethylene
glycol (DEG). While TEG is the most
common glycol used in gas dehydration
applications, it also absorbs
significantly more hydrocarbons
than EG or DEG.
Glycol has a tendency to absorb
for all your solids processing
Experts
Applications:
APIs ∙ Ag-Chemicals
Biologics ∙ Catalysts
Ceramics ∙ Chemicals
Food Ingredients
Herbicides ∙ Minerals
Nutraceuticals ∙ Pesticides
Pharmaceuticals ∙ Pigments
Polymers ∙ Powdered Metals
Proteins ∙ Resins ∙ Vitamins
acid gases. Acid-gas solubility is a
major concern when TEG is used
as an absorbent in gas dehydration
plants. The solubility of acid gas
in TEG is favored at low temperatures,
high pressures, higher TEG
concentration, more TEG solution
circulation rate and higher partial
pressure of acid gas in the feed gas
(see Figures 4 and 5). If acid gas is
present in significant quantities in
the wet gas, then it will increase the
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Mass flowrate, kg/h
Q ual
191
ity &
Since
1

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Chemical Engineering January 2018

Table of Contents for the Digital Edition of Chemical Engineering January 2018