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## Chemical Reaction Engineering ### 1. Introduction #### 1.1. General Definition Chemical reaction engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions, as well as the design of reactors in which these reactions take place. ##### Reactions Reactions can be...

## Chemical Reaction Engineering ### 1. Introduction #### 1.1. General Definition Chemical reaction engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions, as well as the design of reactors in which these reactions take place. ##### Reactions Reactions can be: * **Homogeneous**: Reactants and products are in one phase. * **Heterogeneous**: Reactants and products are in multiple phases. ##### Reactor Types * **Batch**: Reactants are added into a closed system and allowed to react for a certain time. * **Continuous**: Reactants are continuously fed into the reactor and products are continuously removed. * **CSTR (Continuous Stirred-Tank Reactor)**: A continuous reactor with perfect mixing. * **PFR (Plug Flow Reactor)**: A continuous reactor with no mixing in the direction of flow. #### 1.2. Rate of Reaction The rate of reaction is the rate at which a reactant is consumed or a product is formed. $A + B \rightleftharpoons C + D$ Where: * $r_A$ is the rate of disappearance of A * $r_B$ is the rate of disappearance of B * $r_C$ is the rate of formation of C * $r_D$ is the rate of formation of D $r_A = \frac{1}{V} \frac{dN_A}{dt}$ Where: * V is the volume of the reactor * $N_A$ is the number of moles of A * t is the time #### 1.3. Rate Law The rate law is an equation that relates the rate of reaction to the concentration of reactants. $r_A = k[A]^m[B]^n$ Where: * k is the rate constant * m is the order of the reaction with respect to A * n is the order of the reaction with respect to B #### 1.4. Reaction Order * If m = 1: first order reaction with respect to A * If n = 2: second order reaction with respect to B * If m+n = 1: first order overall * If m+n = 2: second order overall #### 1.5. Rate Constant The rate constant is a temperature-dependent parameter that reflects how temperature affects the rate of reaction. $k = Ae^{-\frac{E_a}{RT}}$ Where: * A is the frequency factor * $E_a$ is the activation energy * R is the gas constant * T is the temperature ### 2. Reactor Design #### 2.1. Batch Reactor A batch reactor is a closed system in which reactants are added and allowed to react for a certain time. Mole Balance: $N_{A0} - N_A = \int_0^t (-r_A)V dt$ Where: * $N_{A0}$ is the initial number of moles of A * $N_A$ is the number of moles of A at time t #### 2.2. Continuous Stirred-Tank Reactor (CSTR) A CSTR is a continuous reactor with perfect mixing. Mole Balance: $V = \frac{F_{A0} - F_A}{-r_A}$ Where: * V is the volume of the reactor * $F_{A0}$ is the molar flow rate of A into the reactor * $F_A$ is the molar flow rate of A out of the reactor * $-r_A$ is the rate of disappearance of A #### 2.3. Plug Flow Reactor (PFR) A PFR is a continuous reactor with no mixing in the direction of flow. Mole Balance: $V = \int_{F_{A0}}^{F_A} \frac{dF_A}{r_A}$ Where: * V is the volume of the reactor * $F_{A0}$ is the molar flow rate of A into the reactor * $F_A$ is the molar flow rate of A out of the reactor * $r_A$ is the rate of disappearance of A ### 3. Reactor Network #### 3.1. Reactors in Series Reactors can be connected in series to increase conversion. * CSTRs in series: The conversion increases as the number of reactors increases. * PFRs in series: The total volume required is the same as that for a single PFR with the same conversion. #### 3.2. Reactors in Parallel Reactors can be connected in parallel to increase production rate. * CSTRs in parallel: The conversion is the same as that for a single CSTR with the same total volume. * PFRs in parallel: The conversion is the same as that for a single PFR with the same total volume. ### Nomenclature | Symbol | Definition | | :----- | :---------------------------- | | CRE | Chemical Reaction Engineering | | CSTR | Continuous Stirred-Tank Reactor | | PFR | Plug Flow Reactor | | V | Volume | *** The document provides an overview of chemical reaction engineering, covering fundamental concepts such as reaction types, reactor types (batch, CSTR, PFR), reaction rates, rate laws, and reaction orders. It also discusses reactor design, including mole balances for batch reactors, CSTRs, and PFRs. Additionally, it touches on reactor networks, specifically reactors in series and parallel. A nomenclature table defines key symbols used in the field.