DESIGN OF DISTILLATION COLUMN USING MATLAB FOR SEPARATION OF THERMALLY DEGRADED POLYMERS BANKA SAMIDHA R1, DUTTA M. S.2 1,2
Chemical Engineering Dept., L. D. College of Engineering, Ahmedabad, Gujarat, India -15
[email protected]
Abstract Polymers have revolutionized the life style of human beings since last century, on one side where it has become part and parcel of everyday life on other its degradation and decomposition has been an extreme matter of concern. To this a lot of processes have been experimented and a few commercialized. In the paper presented thermal decomposition of low density polyethene (LDPE), polypropylene and polystyrene are taken as example. Once the polymers are decomposed by any method, it becomes inevitable to segregate the olefins and this is done using a fractional distillation column, similar to that used in Petroleum refining section. Here, it becomes essential to design, model, simulate and optimize the fractional column for efficient performance. This can be easily and systematically done using a globally popular engineering toolbox called MATLAB. Keywords: Polymer Degradation, Distillation Column Design, MATLAB, Plastic De-polymerization, Multicomponent Distillation 1.
INTRODUCTION
Polymers play an important part in our daily lives, its usage has exponentially increased in past century, besides the development and invention of new polymeric materials are increasing the number of these macromolecule. While this development has played an important role for mankind there is a darker more concerned side of it, its decomposition and degradation, has led the engineers of all fields worried. To this, enormous studies, research and experiments are been performed. Few of these are successful and are commercialized. The Polymers as known are formed from monomers which are either obtained or derived from petroleum fractionation. Therefore, there decomposition yields a large amount of CO2, NOx, SOx, and a mixture of olefins. The polymer decomposition is primarily done by pyrolysis followed fractionation distillation column. The use of distillation column incurs a lot of fixed capital as well as operating cost. It is hence essential to have effective, efficient as well as profitable. To do so, it is necessary to model, design, simulate and optimize the distillation column. Since it is a multi-component feed distillation unit it is essential to use computer for rigorous and continual calculation. Since, every polymeric material decomposes into different components it becomes important to have a customizable program as per requirement and this can be fruitfully done by using a globally popular engineering toolbox MATLAB® (Matrix Laboratory).
1.2 Diesel from LDPE (Low Density Polyethene) LDPE waste plastic is collected. Collected all LDPE waste plastic food container cover is washed with liquid soap and dried into room atmosphere. LDPE waste plastic food container cover is hard shape and it is grinded by grinder machine for fit into reactor chamber. After grinder finished LDPE waste plastic put into reactor chamber and placed into reactor inside with LDPE waste plastic as initial feed. Therefore, the entire process can be summed up as LDPE waste plastic to liquefaction then fractionation process to diesel grade fuel collection. For LDPE waste plastic to diesel grade fuel production purposed two type temperature was used one for liquefaction temperature and another for fractionation temperature profile. LDPE waste plastic to liquefaction temperature range is 120-430 ºC and fractional distillation column temperature is 260-290 ºC for diesel grade fuel collection. In the experiment LDPE plastic melting point 120ºC known temperature for that reason LDPE waste plastic to diesel grade fuel collection experiment starting temperature is 120 ºC and finished temperature is 430 ºC. Temperature is increased gradually from 120ºC to up to 430 ºC, then plastic start to melt, then melted plastic turn into liquid phase when temperature increased, then liquid phase plastic turn into vapor when temperature profile more than 300 ºC and at the end vapor travel through fractional distillation column according to their boiling point range wise. Light fraction boiling point hydrocarbon which boiling point range negative that gas will come out faster and is not condense and its call light gas or
natural gas. Low boiling to high boiling point range hydrocarbon is collected different by fractional column and diesel grade fractional fuel is collected in the diagram 13 number collection tank and fractional column number is 7 and temperature range for diesel grade fuel collection at 260-290 ºC. This process is batch process and light gases were purified by using alkali solution wash then transferred into Teflon bag using small pump. Light gas is hydrocarbon mixture such as methane, ethane, propane and butane. Produced diesel grade fuel is purified after finished whole experiment and separated into container for further analysis. Produced fuel density is 0.80g/ml. in this experiment mass balance calculation indicate that initial feed 800 gm LDPE waste plastic to diesel grade liquid fuel is 152 gm, rest of other grade fuel is 584 gm, light gas is from 800 gm initial feed to 32 gm and leftover solid black residue is 32 gm from total initial feed. In percentage calculation for this experiment from 800 gm LDEP waste plastic to diesel grade fuel is 19%, other grade fuels is 73%, and light gas is 4% and solid black residue is 4%. 1.3 Thermal Decomposition of Polypropylene Polypropylene waste plastic is collected and dried into room atmosphere. It is grinded by grinder machine for fit into reactor chamber. After grinder finished waste plastic put into reactor chamber and placed into reactor. Rector temperature can go up to 450 ºC and temperature is monitored by meter for temperature increase and decrease. Reactor is connected with fractional distillation column and temperature profile set up 1st fractional to 5th fractional. The temperature starts from 100 ºC to 400 ºC gradually. When temperature increased from 100 ºC to 250 ºC then plastic is melt and creates vapor and some vapor come out. Some moisture is present inside system and moisture is come out with vapor. Melted waste PP plastic when become fully liquid slurry due to heat increase from 250 ºC to 300 ºC the liquid slurry to turn into vapor at the end vapor travel through fractional column and collected different grade liquid fuel with different percentage. 5th fractional heavy fuel is collected from fractional distillation column and temperature is 340 – 365 ºC. Fuel production is continued until temperature 400 ºC.
1.4 Production of Aromatic Hydrocarbons Naphtha Chemical by Thermal Degradation of Polystyrene
Polystyrene (PS) waste plastic to renewable energy or naphtha grade fuel production through fractional distillation process was applied and PS liquefaction temperature range was 250˚C - 430˚C and fractional column temperature was 110˚C - 135˚C for naphtha grade fuel separation. From, the above two process description it becomes quite lucid that after polymer decomposition the separation using fractionation becomes really important.
Figure 1:Schematic diagram of Polymer decomposition
2 MATLAB 2.1. Introduction to MATLAB MATLAB® is a high-level language and interactive environment for numerical computation, visualization, and programming. Using MATLAB, you can analyse data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spread sheets or traditional programming languages, such as C/C++ or Java™. You can use MATLAB for a range of applications, including signal processing and communications, image and video processing, control systems, test and measurement, computational finance, and computational biology. More than a million engineers and scientists in industry and academia use MATLAB, the language of technical computing.
2.2. Key Features • • •
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High-level language for numerical computation, visualization, and application development Interactive environment for iterative exploration, design, and problem solving Mathematical functions for linear algebra, statistics, Fourier analysis, filtering, optimization, numerical integration, and solving ordinary differential equations Built-in graphics for visualizing data and tools for creating custom plots Development tools for improving code quality and maintainability and maximizing performance Tools for building applications with custom graphical interfaces Functions for integrating MATLAB based algorithms with external applications and languages such as C, Java, .NET, and Microsoft® Excel®
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Coulson J. M., Richardson J. F., Sinnot R. K., Chemical Engineering, Vol. 6,Chemical Engineering design, 3rd ed.,1999 Compendium of Technologies, Converting Waste Plastics into a Resource, Compiled by UNEP Dr. S. Vinothkumar, P. Sudarventhan, “Production of Crude Oil from the Plastic Bags”, SSRG International Journal of Chemical Engineering Research (SSRGIJCER) – volume 1 Issue1 Nov 2014
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Discussion
3.1. Advantages of such Program: It can compute tray to tray composition and thus give fraction of each cut. It gives annual variable cost as well as fixed cost and can thus be used industries for optimum use of column It can be well used for designing of column and comparing the change in reflux ratio with number of trays. It saves time and energy that is otherwise wasted in pen and paper method. Gives accurate answers, corrected up to four decimal places. Programs can be coded as per case or user specific. Complex equations and iterations can be solved easily. It can be well utilized for academics and teaching purposes and a base for research studies.
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Ding W, Liang L, Anderson L. L (1997) Thermal and catalytic degradation of high density polyethylene and commingled postconsumer plastic waste. Fuel Process. Technol. 51, 47–62. McCabe W. L., Smith J. C., Harriot P., Unit Operations of Chemical Engineering,7th ed. McGraw-Hill, New York,2005 Moinuddin Sarker, Mohammad Mamunor Rashid, Polypropylene Waste Plastic Conversion into Fuel Oil by using Thermal Degradation with Fractional Process, American Journal of Environment, Energy and Power Research Vol. 2, No. 3, December 2014, pp. 1 - 10, ISSN: 2329 - 860X Moinuddin Sarker, Mohammad Mamunor Rashid and Muhammad Sadikur Rahman, Thermal Conversion of Polymer Wastes (LDPE) into Hydrocarbon Diesel Fuel without Cracking Catalysts, Int. J. Pure Appl. Sci. Technol., 11(2) (2012), pp. 36-44 Moinuddin Sarker, Mohammad Mamunor Rashid, Muhammad Sadikur Rahman, Mohammed Molla, “A New Kind of Renewable Energy: Production of Aromatic Hydrocarbons Naphtha Chemical by Thermal Degradation of Polystyrene (PS) Waste Plastic”, American Journal of Climate Change, 2012, 1, 145-153 Published Online September 2012 (http://www.SciRP.org/journal/ajcc) Perry R. H., Maloney J. O., Perry's Chemical Engineers' Handbook, 8th ed., McGraw-Hill, New York, 2008 Pratap R., Getting Started with Matlab 7, Oxford University Press, Switzerland, 2006, Chap. 1, 2, 4 Robert E. Treybal, Mass Transfer Operations, McGraw Hill International Publications, 3rd ed., 1981. S.B.Thakore, B.I. Bhatt, Introduction to Process Engineering and Design, McGrawHill, New York. The MathWorks, Inc., Learning MATLAB 7, Fifth printing Revised for MATLAB 7.1, December 2005, Chap. 3, 6, 7 http://www.mathworks.com/academia/student_ version/learnmatlab_sp3.pdf The MathWorks, Inc., MATLAB® Primer, Nineteenth printing Revised for Version 8.0 (R2012b), September 2012, Chap. 1, 5 http://www.mathworks.com/help/pdf_doc/matl ab/getstart.pdf Zhibo Z, Nishio S, Morioka Y, Ueno A, Ohkita H, Tochihara Y (1996) Thermal and chemical recycle of waste polymers. Catal. Today. 29, 303– 308\
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BIOGRAPHICAL DETAILS
Ms. Samidha Banka is a final year post graduate student from L. D. College of Engineering., Ahmedabad. She has completed her under graduate course from Government Engineering College, Bhuj, in 2014, both affiliated to Gujarat Technological University. Prof. S. M. Dutta 6.
graduated in 1995 from NIT, Rourkela and did his post graduation from IIT, Bombay in Chemical Engineering. He has over 15 years of academic experience and 2 years industrial experience. At present he is working as an Associate Professor in Chemical Engineering Department at L.D. College of Engineering, Ahmedabad.
Appendix (Output Windows)
Figure 2: Output Window - 1
Figure 3: Output Window - 2
Figure 4: Output Window - 3
Figure 5: Output Window - 4
Figure 6: Output Window - 5
Figure 7: Output Window - 6
*Not all output windows are shown.
