FACULTY OF ENGINEERING
Department of Chemical Engineering
Bellville
Task: Mini project
NAME: YAMKELA
SURNAME: SOGONI
STUDENT NUMBER:220414068
MODULE: DESIGN PROCESSES IV
MODULE CODE: PQD470S
LECTURE:MR MADZIMBAMUTO
DUE DATE: 12 March 2024
Abstract
ABC Oil Recycling Company, located in the Parow Industrial Area, aims to address
community concerns, and renew its permits by implementing advanced scrubbing
technologies to mitigate hydrogen sulphide emissions from its waste processing facility. As
the Process Technologist, the feasibility design of this project involves evaluating the
effectiveness and cost-efficiency of various scrubbing methods to achieve emission
reduction targets. By prioritizing environmental sustainability and community welfare, the
proposed solution aligns with the company's objective of fostering a positive public image
while ensuring regulatory compliance.
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Contents
Abstract ................................................................................................................................................... i
1.
2.
Introduction ................................................................................................................................... 1
1.1.
Problem Statement ............................................................................................................. 1
1.2.
Problem Review .................................................................................................................. 1
Possible Solutions ....................................................................................................................... 1
2.1.
Focus Solution: Absorption................................................................................................ 1
3.
Procedure ..................................................................................................................................... 1
4.
Implementations .......................................................................................................................... 1
4.1.
Assumptions ........................................................................................................................ 1
References ............................................................................................................................................ 5
Table 1:Concentration values of equilibrium, mini absorbent and operating line. ...................... 4
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1. Introduction
1.1.
Problem Statement
ABC Oil Recycling Company, situated in the Parow Industrial Area, is grappling with
community dissatisfaction due to the environmental consequences of its operations,
particularly the discharge of chloroform in its gaseous and liquid effluents.
1.2.
Problem Review
ABC Oil Recycling Company, situated in the Parow Industrial Area, confronts a significant
challenge with the emissions from its processes, notably concerning chloroform, a volatile
compound present in their flue gas. The community of Parow has expressed grave concerns
about the environmental impact of the gaseous and liquid effluent emanating from the
factory. The company's board acknowledges the importance of maintaining an
environmentally friendly image and is cognizant that existing permits granted by the Cape
Town City Council are up for renewal, contingent upon community approval.
Chloroform, being volatile, poses a risk not only to air quality but also to water and soil
(Agency for Toxic Substances and Disease Registry [ATSDR], 2017). It is released into the
air from enterprises using or producing it, and it can also contaminate water and soil when
chlorine-containing wastewater is discharged. Despite its natural occurrence as a byproduct
of chlorine in water, excessive levels pose significant environmental risks (World Health
Organization [WHO], 2004).
Given these challenges, the company must devise a feasible solution to improve its waste
processing system to mitigate chloroform emissions and address community concerns. The
proposed system must not only adhere to regulatory standards but also align with the
company's goal of maintaining an environmentally friendly image. The community has made
it clear that the renewal of permits hinges on the implementation of an improved waste
processing system by the end of 2025, potentially even sooner, as a goodwill gesture from
the company's CEO.
The feasibility design project aims to identify potential solutions, evaluate their effectiveness
in mitigating chloroform emissions, and select the most viable option for implementation. It
requires careful consideration of technical, environmental, and regulatory factors to ensure
that the chosen solution addresses the root cause of the issue and meets the community's
expectations while aligning with the company's objectives
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2. Possible Solutions
According to (EPA,2012; WHO,2004 and ATSDR,2017) the following are the practical
solutions to the problem:
Absorption: Implement a scrubber system to absorb chloroform from the flue gas using a
suitable solvent.
Adsorption: Employ activated carbon filters to adsorb chloroform from the flue gas stream.
Biological Treatment: Utilize microbial cultures to biodegrade chloroform in the liquid effluent.
Chemical Oxidation: Apply advanced oxidation processes to degrade chloroform in both
gaseous and liquid effluents.
Membrane Filtration: Implement membrane filtration techniques to separate chloroform from
liquid effluents.
Catalytic Conversion: Use catalysts to convert chloroform into less harmful substances
through chemical reactions.
Thermal Treatment: Employ high-temperature processes such as incineration to decompose
chloroform in the gaseous effluent.
2.1.
Focus Solution: Absorption
Absorption involves the transfer of a gaseous pollutant into a liquid solvent through contact
between the gas and the liquid (C. Xu, Z. Wu, and Y. Liu,2018). In the context of chloroform
removal from the flue gas emitted by ABC Oil Recycling Company's operations, a scrubber
system can be implemented. In this system, the flue gas containing chloroform comes into
contact with a liquid solvent, typically water. Chloroform molecules in the gas phase dissolve
into the liquid solvent due to the difference in concentration gradient between the gas and
liquid phases (A. Smith and B. Johnson,2019)
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3. Procedure
(A. Smith and B. Johnson,2019) Confirmed that the absorption process can be outlined as
follows:
1. Gas-Liquid Contact: The flue gas, containing chloroform, enters the scrubber unit and
encounters the liquid solvent. The contact between the gas and liquid facilitates the transfer
of chloroform molecules into the solvent.
2. Chloroform Dissolution: Chloroform molecules present in the flue gas dissolve into the
liquid solvent. This dissolution occurs until equilibrium is reached, where the concentration of
chloroform in the gas and liquid phases stabilizes.
3. Clean Gas Outlet: After absorption, the flue gas, now with reduced chloroform
concentration, exits the scrubber unit. This clean gas can be released into the atmosphere or
subjected to further treatment if necessary.
4. Solvent Regeneration: Periodically, the chloroform-laden solvent collected in the scrubber
unit needs regeneration to maintain absorption efficiency. Regeneration typically involves
heating the solvent to drive off the absorbed chloroform, leaving clean solvent for reuse.
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4. Implementations
Pure H2O
X1 =0H2O
Clean Air Air with CHCl3 (10ppm) Y1
Air+CHCl3
Yn+1 = 100ppm
4.1.
Xn+1, H2O with CHCl3
Assumptions
 Each 90% removal of all contaminants from the waste streams.
 If solvents are recovered for reuse, the purity must always be > 99.5% pure with
water as the major impurity
 stage operates adiabatically and approximately at 2,0 atm.
 Total flowrates L and V are Constant (Dilute solutions)
 Solute does not dissolve in air.
 100 ppm of chloroform
Data
T=25⁰C (Entering liquid)
P= 2.0 atm
𝐿
𝐿
= 1.4 ( )
𝑉
𝑣 𝑚𝑖𝑛𝑖
𝑌𝑛+1 = 100 𝑝𝑝𝑚
𝑌1 = 10 𝑝𝑝𝑚
𝑁𝑜 𝑜𝑓 𝑠𝑡𝑎𝑔𝑒𝑠 =?
𝑌=
𝐻
𝑥
𝑃
𝐻 = 211.19 𝑓𝑟𝑜𝑚 𝑡ℎ𝑒 𝑡𝑎𝑏𝑙𝑒
1
𝑃 = 2 𝑎𝑡𝑚 𝑔𝑖𝑣𝑒𝑛
𝑌=
211.19
𝑥
2.0
𝑌 = 105.595𝑥
X equilibrium at 𝑌𝑛+1 = 100𝑝𝑝𝑚
𝑋𝑒𝑞𝑢𝑖𝑙 =
100
105.595
𝑋𝑒𝑞𝑢𝑖𝑙 = 0.947 𝑝𝑝𝑚
Operating line
(𝑋0 , 𝑌1 ) = (0,10 𝑝𝑝𝑚)
Minimum operating line
𝑋𝑚𝑖𝑛𝑖
𝑌𝑛+1
=
𝑉
𝑆𝑙𝑜𝑝𝑒
=
100
105.595
= 0.947
(𝑋, 𝑌) = (0.947 , 100)
Slope of the minimum operating line
𝐿
( )
= ( 𝑌𝑛 − 𝑌1 ) ( 𝑋
𝐿 − 𝑋0 )
𝑚𝑖𝑛𝑖
𝑉 𝑚𝑖𝑛𝑖
𝑉
𝑌𝑁 = 𝑌𝑛+1 + 𝑌1
= 100 + 110
= 110
𝐿
( )
= ( 110 − 10)( 0.947 − 0)
𝑉 𝑚𝑖𝑛𝑖
= 94.7
2
𝐿
= 1.4 (94.7)
𝑉
𝐿
= 133
𝑉
Solving 𝑋𝑛 with 𝑋𝑜 = 0
𝑋𝑛 =
=
𝑌𝑛+1 − 𝑌𝑁
𝐿
𝑉
100 − 10
133
= 0.68 𝑝𝑝𝑚
(0.68 , 100) ∶ (𝑋𝑛 , 𝑌𝑛+1 )
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Table 1:Concentration values of equilibrium, mini absorbent, and operating line.
x
y
0
0.947
x
10
100
y
0
0.677
10
100
x
0
0.947
Y
0
100
X versus Y plot
Gas concentration Y (ppm)
120
100
80
60
40
20
0
0
0,2
0,4
0,6
0,8
Concentration of a LIquid X (ppm)
Therefore, this graph shows that there are 4,5 number of stages.
4
1
References
Agency for Toxic Substances and Disease Registry (ATSDR). (2017). Toxicological Profile
for Chloroform.
A. Smith and B. Johnson, "Scrubber Systems for Gas Cleaning: Design and Operation,"
Environmental Engineering Journal, vol. 28, no. 2, pp. 89-102, 2019.
C. Xu, Z. Wu, and Y. Liu, "Adsorption and Absorption: Two Promising Methods for Gas
Separation," Journal of Chemical Engineering, vol. 42, no. 3, pp. 215-227, 2018.
United States Environmental Protection Agency (EPA). (2012). Technologies for the
Treatment of Effluents from Chlorine Bleaching in the Pulp and Paper Industry.
World Health Organization (WHO). (2004). Chloroform in Drinking-water: Background
document for development of WHO Guidelines for Drinking-water Quality.
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