IOCL JEA Chemical Engineering Cheat Shee

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1. Technical Core (Chemical Engineering) 1.1 Fluid Mechanics Reynolds Number: $Re = \frac{\rho v D}{\mu}$ (Laminar $Re 4000$) Friction Factor (Darcy-Weisbach): $h_f = f \frac{L}{D} \frac{v^2}{2g_c}$ Hagen-Poiseuille Equation (Laminar Flow): $\Delta P = \frac{32 \mu L \bar{v}}{D^2 g_c}$ Pump Laws: Flow Rate: $Q_2 = Q_1 (\frac{N_2}{N_1})$ Head: $H_2 = H_1 (\frac{N_2}{N_1})^2$ Power: $P_2 = P_1 (\frac{N_2}{N_1})^3$ Flow Meters: Orifice Meter: Measures differential pressure due to flow restriction. $Q \propto \sqrt{\Delta P}$ Venturi Meter: Similar to orifice but with smoother flow, lower pressure drop. Rotameter: Variable area meter, float rises with increasing flow. 1.2 Heat Transfer Heat Conduction (Fourier's Law): $Q = -k A \frac{dT}{dx}$ Heat Convection (Newton's Law of Cooling): $Q = h A \Delta T$ Overall Heat Transfer Coefficient: $\frac{1}{U} = \frac{1}{h_i} + \frac{x}{k} + \frac{1}{h_o} + R_{fi} + R_{fo}$ Log Mean Temperature Difference (LMTD): Counter-current: $\Delta T_{lm} = \frac{\Delta T_1 - \Delta T_2}{\ln(\Delta T_1 / \Delta T_2)}$ Co-current: $\Delta T_{lm} = \frac{\Delta T_1 - \Delta T_2}{\ln(\Delta T_1 / \Delta T_2)}$ (same formula, different $\Delta T_1, \Delta T_2$ definitions) Fouling Factor ($R_f$): Resistance due to deposits on heat transfer surfaces. $R_f = (\frac{1}{U_d} - \frac{1}{U_c})$ Shell and Tube Heat Exchanger: Shell Side: Baffles for turbulence, usually for higher pressure/viscosity fluid. Tube Side: Usually for cleaner fluid, easier to clean. Specifications: Tube diameter, tube pitch, number of passes, baffle spacing. 1.3 Mass Transfer Fick's Law of Diffusion: $J_A = -D_{AB} \frac{dC_A}{dz}$ Distillation: Separation based on volatility difference. Reflux Ratio (R): $\text{L/D}$ (Liquid returned to column / Distillate removed). Types of Reflux: Total reflux (R $\rightarrow \infty$), Minimum reflux (R $\rightarrow R_{min}$), Optimal reflux. McCabe-Thiele Method: Graphical method for determining number of theoretical stages. Absorption: Transfer of a component from gas phase to liquid phase. Henry's Law: $P_A = H C_A$ Stripping: Reverse of absorption, removing component from liquid to gas. Drying: Removal of moisture from solids by evaporation. Constant Rate Period: Surface moisture evaporates, rate is constant. Falling Rate Period: Internal diffusion controls, rate decreases. Critical Moisture Content: Point where constant rate ends. 1.4 Chemical Reaction Engineering (CRE) Rate Law: $-r_A = k C_A^n$ ($n$ = order of reaction). Order of Reactions: Zero Order: $C_A = C_{A0} - kt$ First Order: $\ln(C_A/C_{A0}) = -kt$ Second Order: $1/C_A = 1/C_{A0} + kt$ Activation Energy (Arrhenius Equation): $k = A e^{-E_a/RT}$ Reactor Types: Batch Reactor: Unsteady state, no inflow/outflow during reaction. CSTR (Continuous Stirred Tank Reactor): Well-mixed, uniform composition, $V = \frac{F_{A0} - F_A}{-r_A}$. PFR (Plug Flow Reactor): No radial mixing, composition varies axially, $V = F_{A0} \int_{X_{A0}}^{X_A} \frac{dX_A}{-r_A}$. Comparison: For positive order reactions, PFR is generally smaller than CSTR for same conversion. 1.5 Refinery Operations Cracking: Breaking down long-chain hydrocarbons into shorter, more valuable ones. Thermal Cracking: High temperature, pressure. Catalytic Cracking (FCC): Uses catalysts (zeolites) to enhance selectivity and yield. Reforming: Converting low-octane naphtha into high-octane gasoline components (aromatics, branched paraffins). Catalytic reforming uses platinum catalyst. Octane Number: Measure of a fuel's resistance to knocking/pre-ignition. Higher octane = more resistant. (Iso-octane = 100, n-heptane = 0) Cetane Number: Measure of diesel fuel's ignition delay. Higher cetane = shorter delay, better ignition. (n-hexadecane = 100, alpha-methylnaphthalene = 0) Hydrotreating: Removal of impurities (S, N, metals) from feedstocks using hydrogen and catalysts. Delayed Coking: Severe thermal cracking process to convert heavy residues into lighter products and petroleum coke. 2. Non-Technical 2.1 Quantitative Aptitude (Top 5 Recurring Topics) Time & Work: If A does a work in $x$ days, B in $y$ days, together in $\frac{xy}{x+y}$ days. Percentage: $x\%$ of $y = \frac{x}{100} \times y$. Percentage change: $\frac{\text{New} - \text{Old}}{\text{Old}} \times 100$. Ratio & Proportion: If $a:b$ and $b:c$, then $a:b:c$. Direct/Inverse proportionality. Profit & Loss: Profit = SP - CP, Loss = CP - SP. Profit/Loss % based on CP. Averages: Sum of quantities / Number of quantities. 2.2 Reasoning (Key Patterns) Series Completion: Number series, Alphabet series, Mixed series (identifying pattern: arithmetic, geometric, squares, cubes, prime numbers, alternating patterns). Coding-Decoding: Assigning codes to letters/words based on specific rules (shifting letters, reverse order, numerical values). Blood Relations: Understanding family tree relationships. Direction Sense: Problems involving movement in directions (North, South, East, West) and calculating final position/distance. Syllogism: Drawing conclusions from given statements (All A are B, Some B are C). 2.3 English (Essential Grammar Rules) Active Voice: Subject performs the action (e.g., "The student wrote the essay."). Passive Voice: Action is performed on the subject (e.g., "The essay was written by the student."). (Focus on "be" verb + past participle) Prepositions: Time: at (specific time), on (days), in (months, years, seasons). Place: at (specific point), on (surface), in (enclosed space). Movement: to (destination), into (entering), onto (moving to surface). Subject-Verb Agreement: Singular subject takes singular verb, plural subject takes plural verb. Tenses: Correct usage of simple, continuous, perfect tenses (Present, Past, Future). 3. IOCL Specific GK Current Chairman: S. M. Vaidya (as of latest public information) - *Verify before exam* Refinery Locations (Major): Assam: Digboi, Guwahati, Bongaigaon Bihar: Barauni Gujarat: Vadodara Haryana: Panipat Odisha: Paradip Uttar Pradesh: Mathura West Bengal: Haldia Recent Maharatna Achievements: Focus on green energy initiatives (e.g., green hydrogen, biofuels). Expansion of petrochemicals capacity. Strategic partnerships for energy security. CSR activities and community development. IOCL Status: A Maharatna PSU. 4. Memory Hacks (Mnemonics & Conversions) 4.1 Dimensionless Numbers Reynolds Number ($Re$): " R eally e asy, D on't V anish, P lease M aintain!" ($\rho v D / \mu$) Nusselt Number ($Nu$): " N ice U nderstanding H eat L oss K nowledge" ($h L / k$) Prandtl Number ($Pr$): " P ut R adiant C ooling M edium K indly" ($C_p \mu / k$) Schmidt Number ($Sc$): " S o C urious, M olecule D iffuses D eeply" ($\mu / \rho D_{AB}$) Stanton Number ($St$): " S tudy T horoughly H eat G enerated C onsistently" ($h / G C_p$) 4.2 Unit Conversions Pressure: $1 \text{ atm} = 1.01325 \text{ bar} = 101.325 \text{ kPa} = 760 \text{ mmHg} = 14.696 \text{ psi}$ Energy: $1 \text{ J} = 1 \text{ N} \cdot \text{m} = 1 \text{ W} \cdot \text{s}$ $1 \text{ cal} = 4.184 \text{ J}$ $1 \text{ kWh} = 3.6 \times 10^6 \text{ J}$ Power: $1 \text{ hp} = 745.7 \text{ W}$ Temperature: $K = ^\circ C + 273.15$ $^\circ F = (^\circ C \times 9/5) + 32$