BOTP 115: Industrial Chemical Processes

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Instructor Details

• Instructor's name: Abdulrahman Ali Al Malawi
• Email: [email protected]
• Office location: AD-311 (SECOND FLOOR)

Classroom Policies

• All classes will be conducted in the classroom during the allocated class time
• Attendance is important and will be recorded in the Edugate system
• Attending another section will not count as present for the student
• FOOD or HOT DRINKS are not allowed in the classroom
• Students are encouraged to ask questions or seek clarifications
• Be respectful of everyone in the class session and avoid distractions

Course Contents

• Chapter 1: Olefins
• Chapter 2: Polymers
• Chapter 3: Ethylene Glycol (EG)
• Chapter 4: Methyl tert-butyl Ether (MTBE)
• Chapter 5: Crackers

Assessments and Attendance

• 2 quizzes (25 marks each)
• Final exam (50 marks)
• First quiz will be conducted on week 3 (7-11/7/2024)
• Second quiz will be conducted on week 6 (28/7-1/8/2024)
• Final exam will be conducted on week 9 (18-22/8/2024) (Tentative)
• Attendance is mandatory and will be taken each class

Chapter 1 - Olefins

• Introduction:
  • Hydrocarbon is an organic chemical compound composed mainly of Carbon and Hydrogen
  • Hydrocarbons are colorless and hydrophobic in nature
  • Hydrocarbons originate from plant and animal fossils formed by high temperature and pressure over millions of years
  • Crude oil, natural gas, and natural-gas liquids are all "petroleum" which is the general term for hydrocarbon compounds found in the earth's crust
• Classification of Hydrocarbons:
  • Saturated Hydrocarbons (Alkanes): have only single bonds between atoms, general formula CnH2n+2
  • Unsaturated Hydrocarbons: contain multiple bonds, carbon makes double or triple bonds with other carbon atoms
    • Alkenes (olefins): contain a carbon-carbon double bond, general formula CnH2n
    • Alkynes: contain one or more triple bonds between carbon atoms, general formula CnH2n-2

Alkenes (Olefins)

• Alkenes are unsaturated hydrocarbons containing at least one double or olefinic chemical bond
• Common molecular formula: CnH2n, where n = 1, 2, 3, etc.
• Double bond is called the olefinic bond or ethylenic bond
• Examples of alkenes: ethylene (CH2=CH2), propylene (CH3-CH=CH2), butylene (CH3-CH2-CH=CH2)

Physical Properties of Olefins

• Alkenes with 2-4 carbon atoms are gases, 5-15 are liquids, and higher are solids
• Insoluble in water but soluble in organic solvents
• Density: lighter than water and insoluble in water due to non-polar characteristics
• Boiling Point: depends on molecular mass (chain length), higher molecular mass = higher boiling point

Sources of Olefins

• Not found in crude oil, but manufactured from oil, natural gas, or NGL's by cracking processes
• Cracking processes: Steam Cracking (SC), Fluid Catalytic Cracking (FCC), Fischer-Tropsch (FT), Metathesis, etc.

Uses of Olefins

• Ethylene and propylene are important sources of various industrial chemicals and plastics products
• Butadiene is widely used in synthetic rubber production
• Linear α-Olefins (LAO) are used in several applications in the chemical industry

Olefins Production

• Steam cracking is a conventional process for olefin production

• Feedstocks: ethane, propane, butane, and naphtha or low-boiling gas oil fraction

• Products: ethylene, propylene, butylene, and other olefins### Debutaniser

• Butane, butenes, and butadiene (C4 mixture) are recovered as the top product

• Components heavier than the C4 mixture, i.e., C5 and heavier, are recovered as the pyrolysis gasoline (bottom product)

• Five major licensors of ethylene plants: KBR, Technip, Linde, Shaw, Stone & Webster, and Lummus

Process Variables

• Important process variables are reactor temperature, residence time, and steam/hydrocarbon ratio
• Feed characteristics also influence process severity

Temperature

• Steam cracking reactions are highly endothermic
• Increasing temperature favors the formation of olefins, high molecular weight olefins, and aromatics
• Optimum temperatures are selected to maximize olefin production and minimize carbon deposits

Residence Time

• Short residence times are required for high olefin yield
• Residence times of 0.5-1.2 sec are typical
• Cracking liquid feedstocks for the dual purpose of producing olefins plus BTX aromatics requires relatively longer residence times

Steam/Hydrocarbon Ratio

• A higher steam/hydrocarbon ratio favors olefin formation
• Steam reduces the partial pressure of the hydrocarbon mixture and increases the yield of olefins
• Steam to hydrocarbon weight ratios range between 0.2-1 for ethane and approximately 1-1.2 for liquid feeds

Feedstocks

• Feeds to steam cracking units vary from light hydrocarbon gases to petroleum residues
• Feedstock composition determines operation parameters
• Paraffinic hydrocarbons are easier to crack than cycloparaffins and aromatics

Catalytic Cracking

• Defined as a cracking process that operates at moderate temperatures in the presence of an acidic catalyst
• Principal aim is to crack lower-value stocks and produce higher-value lighter liquids and distillates
• Light hydrocarbon gases can be produced by this process
• Products of catalytic cracking are basically the same as those of thermal cracking
• Zeolites are the most performing solid acidic catalysts

Fluid Catalytic Cracking (FCC)

• Most widely used process for large-scale gasoline production with high octane number
• ZSM-5 Zeolite catalyst is used to increase the yield of light olefins
• Reaction is endothermic
• Reaction temperature ranges from 450 to 560°C

Propane Dehydrogenation (PDH)

• Petrochemical process for the production of propylene from propane
• Catalytic technology utilized for the conversion of propane into propylene and byproduct hydrogen
• Major industrial technologies for PDH:
• CATOFIN
• OLEFLEX
• STAR Krupp-Uhde
• FBD Yarsintez–Snamprogetti
• Linde/BASF
• SABIC integrated FBR / Embedded Dehydrogenation FBR systems
• K-PRO KBR

Catofin Process

• Comprises four stages: propane dehydrogenation to propylene, compression of the reactor discharge, and recovery and refining of the product
• Employs a CrOx/Al2O3 catalyst (chromium-based)
• Operating conditions: 600°C and 0.5 bar temperature and pressure respectively
• Fixed-bed reactor system

Oleflex Process

• Divided into three parts: reaction, product separation, and catalyst regeneration
• Employs the Platinum (Pt) catalyst to carry out the dehydrogenation of propane
• Resulting polymeric grade propylene is obtained by separation and distillation in the presence of the catalyst
• Reaction does not require the use of hydrogen or water vapor as diluents, resulting in lower energy consumption and operational costs