Posted: September 6th, 2022

CHE2162: Project 1
TOTAL = 40 Marks (13% of the unit)
DUE DATE: ninth September 2022, 11:55 pm
Half A
Ammonia (NH3) is a vital feedstock to provide fertilisers. It’s typically produced through the HaberBosch course of, inflicting substantial CO2 emissions. A workforce at Monash College has just lately developed
another course of wherein ammonia will be shaped immediately from nitrogen and hydrogen through an
electrochemical course of. The hydrogen feed comes from a renewable supply. A prototype plant for the
electrochemical manufacturing of ammonia is being constructed at Monash. The next paragraph describes
the method:
A gasoline stream is coming into an electrochemical cell used to provide ammonia from hydrogen and nitrogen
in response to the next response:
𝑁2 + 3𝐻2 → 2 𝑁𝐻3
The recent feed to the method is a combination of nitrogen and hydrogen gasoline in a molar ratio of 1:three at a
stress of 12 bar. A recycling gasoline stream originating from a condenser is blended with the recent feed
and added to the cell. Many of the hydrogen and nitrogen gasoline coming into the electrochemical cell is
transformed to ammonia. There are not any aspect reactions. The system is working in regular state.
A stream of the solvent tetrahydrofuran (THF; C4H4O) is handed by the electrochemical cell at a
circulate price of eight L/min. Because the THF passes by the cell it dissolves all of the ammonia produced within the
response. On the similar time, it’s saturated with nitrogen and hydrogen gasoline. The molar concentrations of
nitrogen and hydrogen gasoline dissolved within the THF stream leaving the electrochemical cell are 25 mM and
75 mM, respectively. Assume that each one nitrogen and hydrogen coming into the electrochemical cell both
react electrochemically or go away the cell as dissolved gasses within the outgoing THF stream. The THF
stream carrying the ammonia and unreacted gases leaving the electrochemical cell then enters a
degassing unit operated at a decrease stress (zero.10 bar). The liquid stream leaving the degassing unit is
recycled again to the electrochemical cell, which consists principally of THF with a small residue of
ammonia and no different parts. The gasoline outlet that carries all N2, H2 and NH3 (assume no THF
being current within the gasoline stream) is compressed again to 12 bar and despatched to a condenser unit. The
condenser produces liquid ammonia at -25°C and a gasoline stream which is recycled again to the mixer
instantly earlier than the electrochemical cell, the place it’s blended with the recent feed earlier than coming into the
electrochemical cell. The gasoline stream leaving the condenser is in equilibrium with the condensed
ammonia. The method produces liquid ammonia at a price of 104 kg/s. The electrochemical cell and the
degassing unit function at a temperature of 20°C.
Extra Info:
● The focus unit 1 mM = 1 mmol/L
● You might use Antoine Equation to estimate the saturation vapor stress of ammonia at -25°C.
Reply the next questions:
a) Draw a course of circulate diagram, indicating all course of streams and unknown variables.
[5 marks]
b) Calculate the molar circulate price of the recent feed stream.
[2 marks]
c) What’s the composition of the recycle gasoline stream leaving the condenser?
[3 marks]
d) Decide the composition (mol fractions) of the gasoline stream leaving the degassing unit.
[6 marks]
e) In a separate experiment to measure the solubility of ammonia in THF at gas-liquid
equilibrium, you discover that the vapour stress of ammonia at zero.15 M ammonia resolution in
THF at 20°C is zero.12 bar. Use this info to estimate the focus of ammonia within the
THF stream leaving the degassing station, assuming it’s in equilibrium with the gasoline stream
leaving the degassing unit. Ignore any quantity expansions of the THF options because of the
dissolution of gasses.
[6 marks]
f) Estimate the focus of ammonia within the THF stream leaving the electrochemical cell.
Ignore any quantity expansions of the THF options because of the dissolution of gasses.
[4 mark]
Half B
Ammonium sulphate is used generally in fertilizers for alkaline soil. It’s a good supply of N for the
crops (containing 21wt% N) and in addition helpful for pH stability. Different makes use of of ammonium sulphate are as
a meals additive and remedy of ingesting water together with chlorine.
Gaseous ammonia and 50 wt% aqueous sulphuric acid resolution are fed to a reactor in stoichiometric
proportions the place they react utterly to type aqueous ammonium sulphate:
2NH3 + H2SO4→ (NH4)2SO4
The aqueous ammonium sulphate resolution leaving the reactor is blended with a recycle stream coming
from a crystalliser. The blended stream passes by an evaporator the place a few of the water is eliminated.
The concentrated resolution leaving the evaporator is saturated at 80°C and passes by a crystalliser
and filter unit which produce anhydrous (NH4)2SO4 crystals at 10°C. The saturated (NH4)2SO4 resolution
at 10°C leaving the crystalliser/filter is recycled to be blended with reactor product stream. The moist filter
cake, containing 95 wt% (NH4)2SO4 crystals and the remaining saturated (NH4)2SO4 resolution at 10°C
is shipped to a dryer the place all the water is eliminated.
Taking a foundation of ammonia produced in Half A of this task, reply the next questions –
(a) The mass circulate price of the recycle stream (kg/h).
[4 marks]
(b) Mass circulate price of the water evaporated within the evaporator and the dryer (kg/h).
[4 marks]
(c) If the water leaving the evaporator is condensed to be blended with a concentrated sulphuric acid
resolution to make the feed resolution of 50 wt% sulphuric acid what could be the mass
composition of the concentrated sulphuric acid resolution. Touch upon why you will need to
recycle the water leaving the evaporator.
[6 marks]
Solubility Knowledge of (NH4)2SO4 in water :
T (°C) Solubility (g/100mL water)
zero 70.6
10 73.zero
20 75.5
30 78.1
40 81.2
50 84.5
60 87.four
80 94.1
100 103.eight
Marking standards: Your options are anticipated to fulfill the next standards:
1. Schematic. Draw a helpful diagram of the system. Symbols, items, flows of supplies/power and
different related properties needs to be outlined on the diagram.
2. Outline the issue. State what you’ll decide, e.g. mass circulate of product stream.
three. Assumptions. Checklist and justify assumptions and simplifications.
four. Knowledge. Clearly state information wanted for calculations, together with items (reference supply the place needed)
5. Assessment. Outline applicable equations, outline all symbols.
6. Calculation. After utterly creating the Assessment in symbols, substitute numerical values and
calculate outcomes. Clearly present and clarify working. Remaining reply needs to be said clearly, with
appropriate items and vital figures.
7. Interpretation & Reflection. Consider your outcomes. How dependable, sensible are they? Are they
constrained by assumptions and simplifications? How might this be addressed? What are probably the most
vital processes, based mostly in your calculations? Are you able to make suggestions on design or
operational parameters? That is to be a concise assertion – not more than a paragraph.

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