This document discusses reaction rates for different phase systems in chemical reactions. It defines reaction rate as the rate at which a chemical loses its identity per unit time and volume. The symbol used for reaction rate is ri. Reaction rates are calculated differently depending on the phase system. For a fluid-solid system, the rate is calculated based on the mass of solid (ri*). For a gas-solid system on a unit surface area, it is calculated based on the surface area (ri**). If considering a gas-solid system based on the volume of solid, it is calculated using the volume of solid (ri***). Finally, the reaction rate can be calculated based on the volume of the entire reactor (ri****). The different definitions of
3. CHEMICAL REACTION
ENGINEERING
Combination of mass transfer, heat transfer,
thermodynamics, economics, fluid mechanics
and chemistry with the aim of properly
designing a chemical reactor.
4. REACTOR
•Reactor is a tank or vessel in which chemical
reaction takes place
•It is a unit for the production of a specified
product from specified reactants.
6. REACTION RATE:
•Rate at which a specie loses its chemical
identity at a particular volume per unit time.
•Units of rate of reaction is
𝑚𝑜𝑙
𝑚3. 𝑠
7. The symbol of reaction rate is ri and its equation is
𝑟I =
1
𝑣
𝑑𝑁𝑖
𝑑𝑡
8. REACTION RATE FOR DIFFERENT PHASE
SYSTEM
• Reaction rate will be different for different phase
systems
For fluid-solid system rate equation will be
𝑟i* =
1
𝑊
𝑑𝑁𝑖
𝑑𝑡
9. CONTINUES…..
•Rate equation for gas-solid on unit surface
𝑟i** =
1
𝑆
𝑑𝑁𝑖
𝑑𝑡
(s is for surface)
For gas solid system on unit volume
𝑟i*** =
1
𝑉𝑠
𝑑𝑁𝑖
𝑑𝑡
(Volume of solid)
10. CONTINUES…..
• Reaction rate for unit volume of reactor
𝑟i**** =
1
𝑉𝑟
𝑑𝑁𝑖
𝑑𝑡
(vr is volume of reactor)
These intensive definations of reaction rate are
related as
Vri = Wri* = Sri** = Vsri***
