College of Engineering and Architecture
Department of Chemical Engineering
Spring 2015- 2016 Semester
IN TERM 2 - ANSWER
CHPE 306 Chemical Process Industries
Date: 13 April 2016
Time: 12:00 PM – 1:15 PM
Venue: 16 L
Faculty: Ms. Marilyn M. Bojangin
Examination Notes :
1. Answer all the questions
2. No cellphones allowed
3. Total number of pages are 6 including the title page
Student Name: Student ID:
Q1. Choose the correct answer [ 2 marks each, total 20 marks ]
1. The Syngas consists of
(a) H2
(b) CO2
(c) A mixture of CO and H2 in varying ratios
(d) CO
2. Major process for steam reforming is
(a) steam reforming of NG or light HC in the presence of O2 or CO2
(b) partial oxidation of heavy HC with steam (H2O) and O2
(c) partial oxidation of coal with steam and O2
(d) all are correct
3. Lower alkenes or olefins are important feed for
(a) production of LDPP or HDPP
(b) catalytic reforming process
(c) gasification of coal
(d) all are correct
4. The following type of polymer cannot be recycled
(a) Phenolic resin
(b) Polyethylene
(c) Polystyrene
(d) both (b) and (c) are correct
5. Bulk chemical derived from syngas
(a) Benzene
(b) Ammonia
(c) Toluene
(d) Polyethylene
6. Primary generation of SO2
(a) Combustion of Sulfur
(b) Oleum is added to water
(c) SO3 is added to concentrated sulfuric acid
(d) SO3 is added to water
7. The following process produces H2 , EXCEPT
(a) Catalytic reforming
(b) Alkylation
(c) Steam reforming
(d) Catalytic Dehydrogenation
8. The main components of glass are
(a) calcium and gypsum
(b) silica, calcium, aluminates and gypsum
(c) silica, calcium and soda
(d) all are correct
9. The advantages of liquid fertilizer are
(a) more uniform composition
(b) less labor
(c) more uninform distribution
(d) all are correct
10. In cascade type sulfuric acid (H2SO4) alkylation process, the feedstock are
(a) Olefins with isobutane
(b) Naptha
(c) Aromatics
(d) Paraffins
Q2. Write the chemical reactions for the following production of the following
[ 5 marks each, total 20 marks ]
1. The Chlor – Alkali using the Electrolysis Process
2. Methanol synthesis CO + 2H2 ↔ CH3OH
CO2 + 3H2 ↔ CH3OH + H2O
3. Sulfuric acid
S + O2 ------SO2
2 SO2+ O2 2SO3
SO3 + H2O H2SO4
4. Catalytic dehydrogenation of the Propane to Propylene
C3 H 8 ------C3H 6 + H 2
Q3. Answer the following questions in the manufacturing of Portland Cement
[ 5 marks each, total 10 marks ]
1. What are the 3 primary constituents of the raw materials used in the manufacture of Portland Cement :
Answer : lime, silica, alumina
2. Identify the four main steps in the cement manufacturing :
Answer : 1- Quarry, 2- raw grinding, 3- burning, grinding, 4- storage & packing
Q4. Read the following PFD for a typical formaldehyde process (Figure Q4 ) and answer the following questions :
[ 5 marks each, total 25 marks ]
Figure Q4. Flow scheme of a typical formaldehyde process plant
1. What are the feeds to the reactor ?
Evaporated methanol, air and steam
2. Write the chemical reaction occurring on the reactor
In the reactor most of the methanol is converted into formaldehyde when mixed gas passes through the catalyst.
CH3OH = CH2O + H2 and CH3OH + 1/2O2 --- CH2O + H2O
3. Name the products emerging from the reactor
Formaldehyde, water, hydrogen, CO2 and non converted methanol
4. What is the purpose of the waste heat boiler ?
The reacted gas is immediately quenched in the waste heat boiler integrated with the reactor. At the same time, the waste heat boiler recovers reaction heat to generate steam, which is effectively used as heat sources for the methanol evaporator and other heaters and steam supply for the mixer.
5. What is the function of the absorption tower ?
The residual methanol and formaldehyde from the tail gas is removed in the top of the absorber by countercurrent contact with clean process water.
Q5. Read the following PFD for the production of LLDPE and HDPE (Figure Q5 ) and answer the following questions :
[ 5 marks each, total 25 marks ]
Figure Q5. Process for the production of LLDPE and HDPE
1. Ethene, hydrogen and comonomer are fed to the reactor through a grid, what is the purpose of the grid ?
Grid provides an even distribution of the gas feeds to the reactor which helps in the more efficient heat transfer inside the reactor
2. What is the purpose of the large diameter section of the reactor ?
At the larger diameter section of the reactor, the gas velocity is reduced which allows entrained particles to fall back into the bed.
3. Describe what is the process occurring in the first cylone ?
Remaining polymer particles are separated from gaseous monomer in the first cyclone and returned to the reactor.
4. Identify the upstream and downstream product of the second cyclone .
Upstream product is the residual monomer (ethane) and the downstream product is the polymer (polyethylene )
5. What are the products of the reactor
Polyethylene, unreacted ethylene and comonomer
END OF PAPER -
5