Quality Control Analysis of Natural Gas Condensate Products through Refining Process Sarker, K., Faruque, M.O. (2017).Quality Control Analysis of Natural Gas Condensate Products through Refining Process.In International Conference on Engineering, Research, Innovation and Education.Shahjalal University of Science and Technology, Sylhet, Bangladesh, January 13-15. Sylhet, Bangladesh: School of Applied Sciences and Technology. 529-534.

1. ICERIE 2017_096
* Corresponding author: kaushiksarker67@gmail.com
Proceedings of the
International Conference on Engineering Research, Innovation and Education
2017
ICERIE 2017, 13 ̶ 15 January, SUST, Sylhet, Bangladesh
Quality Control Analysis of Natural Gas Condensate Products through
Refining Process
Kaushik Sarker 1,*
and Mohammed Omar Faruque1
1
Department of Petroleum and Mining Engineering, Shahjalal University of Science & Technology,
Sylhet, Bangladesh.
Email: kaushiksarker67@gmail.com
faruquepge@gmail.com
Keywords:
 Gas Condensate
Refining;
 Product Quality;
 Quality Control;
 Specification of
Products;
 Laboratory
Data;
 Quality Control
Procedure.
Abstract: Natural Gas Condensate refining is the fractionation of gas
condensate into different valuable products by distillation. The purity of these
products depends on some quality specifications, which are mainly the values
of certain properties of these products. The technique of controlling these
values to get products with desired properties is known as “Quality Control”
(Jones, D. S.J. et. al., 2006). Quality control is done during the process based
on laboratory data. Product quality control is done by manipulating different
process parameters i.e. feed rate, reflux ratio, thermic fluid temperature,
thermic fluid pressure and thermic fluid flow rate. This paper contains data of
specifications of different products produced in gas condensate refining process
with respective testing methods. This analysis is based on the field observation
of two refineries: Universal Refinery Ltd. and Lark Petroleum Ltd. situated in
Sitakund, Chittagong, Bangladesh. This paper is mostly concerned with the
quality control procedure and quality specifications of products in gas
condensate refining process.
1. INTRODUCTION
Gas condensate is one of the dominant fuel resources in modern age. Some products coming from gas
condensate are motor spirit (MS), kerosene, diesel, mineral turpentine oil (MTO), special boiling point solvent
(SBPS) etc. which are used in industry and normal life. Gas condensate is being fractionated into various
products across various refineries in Bangladesh.
Gas condensate is hydrocarbon mixture that exists in gaseous state in sub-surface under high reservoir
pressure condition but condenses into liquid when produced at the surface because of lowering of pressure
(Imam, B., 2005). Condensate is colorless or light yellow liquid hydrocarbon. It has API gravity higher than 55
(Condensate., 2016). Natural gas condensate is typically composed of hydrocarbon ranging from C4 to C15
(Sujan, S.M.A. et. al., 2015).It has specific gravity ranging from 0.5 to 0.8 (Natural-gas condensate., 2016).

2. 530 | Sarker, K. et. al., I C E R I E 2 0 1 7
Gas condensate can be used efficiently only after being fractionated into different valuable products. This
review is based on broad analysis of quality control of these products in refining process. Gas condensate
refining is the process of fractionation of gas condensate into different products by distillation through a packed
column. And quality control is an important part of this process. Quality control means ensuring that the
properties of different products remain in a value range which is the measurement of the purity and usefulness
of that product. There is a certain specification for each parameter of that product. These parameters are
measured in lab using different methods to measure value of parameters such as specific gravity, viscosity, flash
point, pour point, smoke point etc. And the process is manipulated by manipulating different process parameters
such as: feed rate, reflux ratio, thermic fluid temperature and rate and thermic fluid flow rate. These
manipulations are done according to the correction required in parameter values of the products.
The objective of this paper is to provide data of specifications of different gas condensate refining process
products and describing the process of quality control according to these specification parameters. In this paper
the quality control analysis of gas condensate refining process has been provided based on different theoretical
studies and field observation of two gas condensate refineries: Universal Refinery Ltd. and Lark Petroleum Ltd.
based on Sitakund, Chittagong, Bangladesh.
2. METHODOLOGY
It is pre-requisite to study necessary books and journals from library and internet to get the necessary
knowledge about the gas condensate refining and specially quality control of the products. Primary data is
collected on refineries across Bangladesh. A process plant is selected for field observation to gather practical
knowledge about gas condensate refinery product quality control procedure. After that, data is acquired from the
field and the process of quality control as well as laboratory analysis is observed. The data includes different P
& I diagrams, equipment and instruments of process, the specification of raw material and products, methods
used to asses different parameters of the products. The diagram is drawn by E-Draw Max 7.9 software. After all
of that, the quality control process is being studied and an analytical review is given.
2.1 Work Flowchart
Literature Review
Primary Data Collection
Process Plant Selection
Visiting a Plant
Acquiring Knowledge regarding
Process & Quality Control
Gathering Necessary Data and
information based on Quality
Control
Analysis and Review

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3. FIGURES
Figure 1 Gas Condensate Fractionation Process (Normal Operation).
(Arihant Engineers., 2013)
4. TABLES
Table 1 Specifications of Rashidpur Gas Condensate (BCIC, 2015)
Properties Unit Value
1. Density at 150
C g/ml 0.7974
2. Total Sulfur Wt% 0.056
3. ASTM Boiling Point Range (0
C) 61-302
Table 2 Specification of Special Boiling Point Solvent (SBPS) (BCIC, 2015)
Test Method Limit
1. Density at 15°C,Kg/L ASTM D 1298 Min. 0.6700
2. Boiling Point Range, °C ASTM D 86 60-90

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Table 3 Specification of Light Solvent (Naphtha) (BCIC, 2015)
Tests Method Limit
1. Density at 15°C, Kg/L ASTM D 1298 0.6700-0.7400
2. Boiling Point Range, °C ASTM D 86 90-150
Table 4 Specifications of Motor Spirit (BCIC, 2015)
Tests Methods Limit
1. Density at 15°C, Kg/L ASTM D 1298 0.7700
2. Boiling Point Range, °C ASTM D 86 60-210
Table 5 Specifications of Mineral Turpentine Oil (MTO) (BCIC, 2015)
Tests Methods Limits
1. Density at 15 °C, Kg/L ASTM D 1298 Min. 0.8200
2. Boiling Point Range, °C ASTM D 86 150-210
3. Flash Point (Able), °F IP 170 Min. 85
Table 6 Specifications of Super Kerosene Oil (SKO) (BCIC, 2015)
Tests Methods Limits
1. Density at 15 °C ASTM D 1298 0.8250
2. Smoke Point, mm ASTM D 1322 Min. 20
3. Distillation range, °C ASTM D 86 90-260
Table 7 Specification of High Speed Diesel (HSD) (BCIC, 2015)
Tests Methods Limits
1. Density at 15 °C Kg/L ASTM D 1298 0.8200-0.8700
2. Pour Point, °C ASTM D 97 9-12
3. Boiling Point Range, °C ASTM D 86 210-302

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5. QUALITY CONTROL ANALYSIS
5.1 Process Overview
Feed condensate is taken to distillation still where it is boiled by thermic fluid of 150o
C. Refrigerated water
(10-15o
C) for fractions boiling below 65o
C and cooling water for fractions boiling above 65o
C is used as cooling
media in coolers and condensers. Thermic fluid temperature is controlled within 50 to 80o
C of the bulk fluid
temperature. When temperature of still rises above IBP (60o
C), vapor rises into distillation column packed with
SS304 structured packing, where fractionation takes place. Counter current contact and rectification takes place
with down coming and reflux liquid. Top temperature of the Column is taken as control ‘Cut off’ temperature
for different fractions. The vapors then reach condenser where they are condensed and sent to reflux drum
through sub-cooler. In reflux drum water and hydrocarbon is separated and a controlled quantity of hydrocarbon
is sent back to distillation column while rest is sent to product tank through product coolers. There are separate
coolers for light and heavy product to prevent them from mixing together. After FBP of last designated product
is reached distillation is stopped and residue is sent through residue coolers and reticulated back to still to cool
the batch. Bottom residue product is gradually drawn out and passed through the Residue Cooler.
5.2 Quality Control Procedure
During production products are being tested after being taken from the process and then tested in lab, using
different methods for different parameters given in tables above. Different parameters are measured in lab and
matched with the parameter specification given in the tables. The closer the product parameter values to the
chart, the more quality the product has. For a steady state operation, following parameters should remain steady
at a fixed feed rate: 1) Distillation Still liquid level, 2) Distillation Still liquid temperature, 3) Column top vapor
temperature. For any feed stock input rate, if the column top temperature falls below the set point, the reflux rate
needs to be decreased and top product withdrawal should be increased. There will be a corresponding reduction
in residual product withdrawal as the liquid level in the Still is maintained. If the column top temperature rises
above the set point the reflux must be increased and the top product withdrawal must be reduced. There will be a
corresponding increase in the bottom product withdrawal. If the column operation does not stabilize by change
of reflux as above, the feed rate must be changed and operating conditions must be stabilized. During these
operations the thermic fluid temperature is to be maintained at a fixed value. Difference between the Still liquid
and coil exit TF temperature should be maintained between 50 to 80o
C. TF temperature could also be used as an
additional parameter to control the product quality. If the column top temperature is below the set point, it could
be set right by increasing the TF temperature. Increasing TF temperature will lead to less volatiles in bottom
product and increase of FBP of top product. If the column top temperature is above the set point, it could be set
right by reducing the TF temperature. This will lead to reduction in FBP of top product and increase of volatiles
in bottom product. Thus by manipulation of: Feed rate, Reflux ratio, TF temperature and rate, TF flow rate -
output and quality of top and bottom products could be controlled. The plant is kept running under these
conditions for a long period, till the feed stock is available.
6. RESULT AND DISCUSSION
Quality control is mainly done by a trial and error method based on process control and laboratory analysis.
Product sample taken from process is analyzed in laboratory to find the values of different specification
parameters of the products which represent the product quality. From the overview stated above, information
can be acquired about the fractionation process and quality control procedure. Information on specifications of
product parameters can also be found from table: 2 to table: 7. The most important parameter is boiling point
range or the cut-off temperature. The accuracy of the temperature range maintained during process is the prime
determiner of product quality.

6. 534 | Sarker, K. et. al., I C E R I E 2 0 1 7
The boiling point range for different products can be summarized in the table given below:
Product Boiling Point Range (°C)
Special Boiling Point Solvent (SBPS) 60-90
Light Solvent (Naphtha) 90-150
Motor Spirit 60-210
Mineral Turpentine Oil (MTO) 150-210
Super Kerosene Oil (SKO) 90-260
High Speed Diesel (HSD) 210-302
7. CONCLUSION
Gas condensate refining is a growing industry in Bangladesh. There are several private companies who have
started gas condensate refining. So, this paper about quality control in gas condensate refining process is very
important. The quality of product is the most crucial thing in gas condensate refining process. The efficiency of
the process is measured by quality of products. So, good quality products are the marks of a successful process.
The process of quality control and specifications of product quality has been described in this paper. Product
quality is analyzed in laboratory and the process parameters are maintained at a point of optimization to control
the quality of products. Thus, by maintaining a constant procedure of quality testing and quality control the
product quality is ensured.
REFERENCES
Arihant Engineers. (2013) ‘Equity Refinery Limited’.
BCIC. (2015) ‘Bangladesh Chemical Industries Corporations’.
Condensate. (2016) Available at: http://en.banglapedia.org/index.php?title=Condensate (accessed on October
13, 2016).
Imam, B. (2005). Energy resources of Bangladesh.1st edition. Dhaka: University Grants Commission of
Bangladesh, pp. 76.
Jones, D.S.J., Pujado, P.R. (2006). Handbook of Petroleum Processing. 1st edition. Dordrecht: Springer
Publication, pp. 705.
Natural-gas condensate. (2016) Available at: https://en.wikipedia.org/wiki/Natural-gas_condensate (accessed on
October 13, 2016).
Sujan, S.M.A., Jamal, M.S., Hossain, M. and Ismail, M. (2015) ‘Analysis of gas condensate and its different
fractions of Bibiyana gas field to produce valuable products’, Bangladesh J. Sci. Ind. Res.50 (1), pp. 59-64.