Petrochemical Process Technology

Petrochemical industry is closely linked to the socio-economic aspiration of people and petrochemicals have become now a part of life and providing the basic needs of mankind. Starting from synthetic fiber to polymers, synthetic rubber, explosive, dyes intermediates, pharmaceuticals, pesticides no industrial sector is left where the petrochemicals are not used in some or other forms. Quantitatively, 95% of the organic chemicals are now based on petrochemicals derived from natural gas and petroleum feedstocks. Now the petrochemicals have virtually replaced the original natural feedstocks oil, fat, coal and molasses. Petrochemical Industries have undergone tremendous growth and modernisation. Since its birth in 1920 when first petrochemical isopropyl alcohol was manufactured from propylene obtained from cracking plant of petroleum refinery, there has been continuous upgradation in the process technologies and now new bread of petrochemical complexes are available with much higher capacities than what it was available in early sixties.

I would like to express my sincere gratitude to Dr S.J. Chopra, Chancellor, University of Petroleum & Energy Studies (UPES) for his encouragement, inspiration and valuable comments and foreword in second edition. I would like to express my sincere gratitude to the various Institutes and Universities for encouraging response and introducing my book as a textbook in their curriculum, without which the second edition of the book was not possible. I would like to express my sincere gratitude to Dr R.A. Mashelkar, former Director General CSIR, for going through the first edition of the manuscript and giving his valuable suggestions and writing the foreword for the first edition. I am greatly indebted to Dr S.N. Upadhyaya, former Director, Institute of Technology, Banaras Hindu University, who has always been a source of inspiration and encouragement

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Petrochemical industry has been playing an important role in the social, cultural and economic growth of a nation and in providing basic needs of mankind—food, shelter and clothing. Petrochemicals have become an indispensable part of our life and are playing an important role in providing key feedstock for chemical industry for making thousands of different chemicals the general people usually encounter as end or consumer products.

Although Indian petroleum and petrochemical industries are not very old, they have revolutionised our life and are providing the major basic needs of rapidly growing, expanding and highly technical civilisation as a source of energy for domestic, industrial, transport sectors and as feedstock for fertilisers, synthetic fibres, synthetic rubbers, polymers, intermediates, explosives, agrochemicals, dyes, and paints etc.

Petroleum and Petrochemicals have revolutionised our life and are providing the major basic needs of rapidly growing, expanding, and highly technical civilisation as a source of energy for domestic, industrial, transport sectors and as feedstock for fertilisers, synthetic fibres, synthetic rubber, polymers, intermediates, explosives, agrochemicals, dyes, paints, etc. Globally it processes more material than any other industry.

Olefins are major building blocks for petrochemicals. Because of their reactivity and versatility, olefins especially the light olefins like ethylene, propylene, butenes, butadiene, etc., there has been tremendous growth in the demand of the olefins.

With the rising demand of ethylene and propylene, there has been a tremendous growth in the steam cracking of hydrocarbons during the last four decades. Similarly, FCC (Fluid Catalytic Cracking) has developed into a major upgrading process in the petroleum refinery industry for the conversion of heavy fuel oil into more valuable products ranging from light olefins to naphtha and middle distillate. Large amounts of C4 and C5 compounds are produced along with the production of ethylene in steam cracking and gasoline in FCC. C4 & C5 streams are important source of feedstock for synthetic rubber.

Aromatic hydrocarbons—benzene, toluene, xylenes, ethyl benzene, and naphthalenes are important petrochemicals and find application in the manufacture of large number of intermediates and are the basic building blocks for large number of products—synthetic fibres, elastomers, explosives, pesticides, dyes, detergent, phenolic resins, epoxy resins, polyurethane, etc

Methane and synthesis gas are important petrochemical feedstock for manufacture of large number of chemicals, which are used directly or as intermediates. Many of these product are finding use in plastic, synthetic fibre, rubber, pharmaceutical and other industries.

Ethylene is one of the most versatile petrochemicals and its production has steadily increased over the years. Ethylene is known as king of chemicals and surpasses all organic chemicals in production and in amount sold. Ethylene is the basic building block for petrochemicals, generally leveraged off GDP with rates of increase between 1.0-1.1 times GDP growth in the mature economics, up to 1.5 and more times the GDP in high growth industrialising economics [Swanson, 2003].

Propylene often referred as the crown prince of petrochemicals is superficially similar to ethylene but there are many differences both in production and uses [Hatch & Matar, 1978]. Propylene is used in many of the world’s largest and fastest growing synthetic materials and thermoplastics. The demand of propylene has increased rapidly during the last twenty years and is primarily driven by polypropylene demand. According to CMAI, global capacity of propylene during 2005 was 67.1 million tonnes. Worldwide propylene demand will grow 4.1 per cent per annum during next ten years [Bjacek, 2004].

C4 and C5 hydrocarbons from FCC and cracker plant have received worldwide interest for recovery of value added products finding application as chemical feedstock and intermediates, oxygenates, alkylate. C4 olefins and their derivatives offer many potential applications for manufacture of a large number of intermediates which are being used in synthetic, plastics, stabilisers, plasticisers, solvents, gasoline additives, organic glasses, adhesives, antioxidants, rubber accelerators, herbicides, etc.

Aromatic hydrocarbons, especially benzene, toluene, xylene (BTX), and ethyl benzene are major feedstocks for large number of intermediates which are used in the production of synthetic fibres, resins, synthetic rubber, explosives, pesticides, detergent, dyes, intermediates, etc. Styrene, linear alkyl benzene, and cumene are the major consumer of benzene. Benzene’s is one of the most versatile chemicals used for variety of intermediates and pesticides.

Polymers were accidentally synthesised, however, as more and more applications of polymers were later discovered, this ensured a new era in their utility for the society [Venkatraghvan, 1999], however, wonder of polymers now cuts across all sections of society. Polymers are material of choice due to their versatility, their physical and chemical strengths, lightness in weight, chemical and corrosion resistance, economic viability, easy processability and also their attractiveness & durability in all weather conditions.

Although history of textile market using natural fibres is ancient, eighteenth and nineteenth century witnessed an era of industrial revolution resulting in tremendous upsurge in fibre production. Synthetic fibres are the indirect consequence of spectacular growth in petrochemical industries and are playing an important role in meeting the demand of one of the three basic needs of mankind– food, cloth and shelter. Synthetic fibres have been traditionally playing a supplemental role to cotton but due to shortage of cotton and resultant high prices have propelled synthetic fibre industry to the fore. There has been phenomenal growth to the synthetic fibre industry during recent years due to growth of petrochemical industry. The synthetic fibre industry based on petrochemicals consists of polyamides, polyester, acrylics and polypropylene fibres and enjoys major share in international business and marketing. Viscose rayon based on natural fibres is also one of the important synthetic fibres.

Rapid industrialisation, unplanned urban development, increasing automobile emission has resulted in serious environmental degradation. To defend and to improve environment for present and future generations by making industrial plants healthier and more pleasant to work, mitigating impact of industrialisation by eco-friendly greener technologies, preserving ecological balance has become an imperative goal of mankind. Inspite of their significant contribution in meeting basic needs of mankind, making their life happier and comfortable petrochemical industries are amongst the top seventeen highly polluting industries notified by Central Pollution Control Board of India for which EIA has been made mandatory.

Corrosion is recognised as one of the most serious problems in modern societies with the resulting losses each year amounting hundreds of billion dollars. It is estimated that annual corrosion costs ranged approximately 1-5% of the GNP of each nation [http://www.corrosiondoctors.org/ principles/cost.html]. Corrosion has been a cause of major concern in chemical processes because it encompasses a broad range of conditions and chemicals. Corrosion in chemical process industries is incurring huge losses in terms of unscheduled downtime resulting in production losses, reduced equipment life, high maintenance and corrosion control costs, replacement costs, huge loss of properties and sometimes even injury or death. It is like a cancer cell that often slowly develops for many years and remains undetected and when observed, it may be too late to mend the damage caused by it. Chemical process industry spends more than any other industry in order to replace or repair the corroded equipment and structures.

Global energy crisis due to rising cost of fossil fuels and depleting energy resources has brought awareness for energy conservation in both developed and developing countries. Reducing specific thermal energy cost has been one of the major considerations for various developments which have taken place in almost all sectors. Cost of energy in chemical and petrochemical industry is the major cost of production [Hoehn et al., 2011]. • High energy prices and consequent impact on operating costs as well as the drive to reduce greenhouse gas emissions are providing petroleum & petrochemical complexes with incentive to explore opportunities for energy optimisation which involves one or more of following options. • Improved operation and control of process units. This can involve adjustments of processing conditions that can lead to energy optimised operation. • Improved heat recovery schemes involving increased heat integration across process units. • Use of advanced process technology involving improved equipment design, better catalyst etc. • Hydrogen and fuel gas management and such maximum hydrogen and LPG recovery. • Utilities optimisation.

Petrochemical Industry is called mother of chemical industry as it is a building block for synthesis gas, olefins, aromatics, which are used for manufacture of basic chemicals and feedstocks for polymer, synthetic fibre, synthetic rubber, explosives, agrichemicals, dyes and intermediates, plasticisers, packaging materials etc. Petrochemical industry is called American phenomenon. It started in 1920s with production of isopropanol from FCC gases and small capacity ethylene crackers. Since then there has been tremendous growth during last fifty years. Main driving force for growth of petrochemical industry has been the availability of feedstock from petroleum industry, developments in catalyst and separation processes and growing market due to fast growing population.

Last century has been the period of phenomenal growth in industrialisation and urbanisation. post World War-II, stunning growth in size, complexity and diversity has been experienced in all industrial-manufacturing sectors. Chemical industry is no exception. Chemical industry is one of the prominent indicators of industrial growth in any country and touches almost every aspect of our life and has provided enormous benefits to the world community by providing the basic needs.