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

1. CRE, REACTION RATE FOR DIFFERENT PHASE
SYSTEM

2. CONTENTS
1. definition
2. explanation
3. reaction rate
4. reaction equation for different phase
system

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.

5. PURPOSE OF REACTOR:
•Kinetics
•Provide residence or contact time
•Contact pattern and performance

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***