Chemcad As A Tool When Teaching Chemical Engineering

Faculty of Technology and Science
Department of Chemical Engineering

IMRAN ULLAH KHAN

CHEMCAD as a tool when teaching Chemical Engineering

Degree Project of 30 credit points
Master of Science in Engineering,
Degree Program in Chemical Engineering

Date/Term: 2011-10-25
Supervisor: Lars Nilsson, KaU
Examiner: Lars Järnström, KaU

Karlstads universitet 651 88 Karlstad
Tfn 054-70010 00 Fax 054-700 14 60
Information@kau.se www.kau.se

Abstract:
The aim of this project was to design different chemical processes using Chemcad software.
Following five Chemcad models that had industrial relevance were designed and discussed,
production of nitric acid by ammonia oxidation process, Production of sodium carbonate by
Solvay process, production of hydrogen by steamreforming of natural gas, production of
sulphuric acid by Contact process and production of sulphur by Claus process. Equilibrium
reactor, Gibbs reactor, absorption tower, heat exchangers, condensers, separators, pumps,
compressors and mixers are designed on flow sheet diagram using Chemcad software. Mass
balances and energy balances of Chemcad models were compared with bachelor thesis work and
theirdifferences and similarities were discussed in detail. In all processes reasonable results were
obtained. Mostly in all cases results are the same as in the bachelor thesis. It was seen that
equilibrium reactors give better results as compare to Gibbs reactors because when conversion
factor of the chemical reaction was not known, Gibbs reactor was used and it adjust the
conversion by itselfaccording to equilibrium concentrations of the compounds. SI unit system
was used in Chemcad models because in Sweden the SI system is very well established.

Master Thesis

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Executive Summary:
The purpose of this work is to solve mass and energy balances for chemical engineering systems
and designing of equipments by applying a flow sheeting Chemcad program. Also provide a listof carefully checked chemical engineering processes on flow sheeting system using Chemcad
software. Chemcad is frequently used in process industries flow sheets. Different unit operations
are solved in flow sheeting system using Chemcad software. Different equipments like
Equilibrium reactors, Gibbs reactors, absorption towers, Pumps, mixer, compressors, dividers,
heat exchangers and separatorsare designed on flow sheets using Chemcad. Bachelor thesis
calculations are compared with Chemcad results and their results are discussed.
Five chemical process industries were designed on flow sheet system using Chemcad. These
process industries are,
a. production of nitric acid by ammonia oxidation process
b. Production of sodium carbonate by Solvay process
c. Production of hydrogen bysteam reforming of natural gas
d. Production of sulphuric acid by Contact process
e. Production of sulphur by Claus process.
Ammonia oxidation process raw materials are ammonia, air and water. Compositions of
products, material balances and energy balances are compared with Salman [1]. Ammonia is
converted into nitric acid by following reactions,
4NH3 + 5O2

4NO + 6H2O

NO + 0.5 O2(exothermic reaction)

NO2
2HNO3 + NO (exothermic reaction)

3 NO2 + H2O

Solvay process raw materials are sodium chloride (NaCl); lime stone (CaCO3) and ammonia
(NH3). Compositions of products, material balances and energy balances are compared with
Khan [5]. Solvay process gives sodium carbonate by following main reactions,
CaCO3
CaO + H2O
NaCl + NH4OH + CO2
2NaHCO3

CaO + CO2 (80%conversion, endothermic reaction)
Ca (OH) 2

(exothermic reaction)

NH4Cl + NaHCO3 (75% conversion, exothermic reaction)
Na2CO3+ CO2 + H2O (endothermic reaction)

Hydrogen production process is designed on Chemcad in two flow sheets using different types of
reactors. Raw materials for the production of hydrogen are natural gas and steam. Compositions

Master Thesis

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