The objective of this experiment was to get a firsthand experience of the preparation of a catalyst for methanation reaction and to evaluate the performance of the catalyst in a fixed bed tubular reactor. In the first part of the experiment a nickel-based catalyst was synthesized. The catalyst will have nickel as the active component and alumina as the support. the catalyst precursor was prepared by co-precipitation from a solution of nitrate salts of nickel and aluminum. The precipitate was filtered out, washed, dried and calcined to obtain the catalyst. In the second part, the catalyst was activated and performance analysis was done alone with loaded in a fixed bed reactor. The percentage conversion of CO to CH4 was 96.38% and the selectivity of CH4 production to CO2 production was 3.348.

1. i
Bangladesh University of Engineering and Technology
Course No: CHE 402
Course Name: Chemical Engineering Laboratory-V
Experiment No. 01
Name of the Experiment: Formulation and Operation of a
Nickel-Based Methanation Catalyst.
Date of Performance: 24.06.2019
Date of Submission: 31.06.2019
Submitted by – Group – 1 (A2)
Tauhid Roman 1502041
Saiful Islam 1502042
Fahim Shahriar Sakib 1502043
Riazuddin Ahmed 1502044
Swadesh Karmoker 1502045
Submitted To-
Dr. Md. Iqbal Hossain
Assistant Professor
Dept. Of Chemical Engineering, BUET

2. ii
Summary
A catalyst is a substance that increases the rate of a chemical reaction. The amount of catalyst
before the reaction and after the reaction remains same. The action of catalyst onto the reaction is
called catalysis. The objective of this experiment was to get a firsthand experience of the
preparation of a catalyst for methanation reaction and to evaluate the performance of the catalyst
in a fixed bed tubular reactor. In the first part of the experiment a nickel-based catalyst was
synthesized. The catalyst will have nickel as the active component and alumina as the support. the
catalyst precursor was prepared by co-precipitation from a solution of nitrate salts of nickel and
aluminum. The precipitate was filtered out, washed, dried and calcined to obtain the catalyst. In
the second part, the catalyst was activated and performance analysis was done alone with loaded
in a fixed bed reactor. The percentage conversion of CO to CH4 was 96.38% and the selectivity of
CH4 production to CO2 production was 3.348.

3. 3
Table of Contents
Page No.
1. Theory 5
2. Experimental section 14
3. Observed data 19
4. Calculated data 20
5. Sample calculation 21
6. Results and discussions 24
List of Tables
 Gas chromatography test data 19
 Outlet gas composition (mole %) from GC (dry basis) 20
 Outlet gas flow rate (gm-mole/hr) from GC 21

4. 4
List of Figures
1. Catalyst effect on activation energy 05
2. Setup of a Gas Chromatography 09
3. Injector in different modes 11
4. Weighing the Ni(NO3)2 and Al2(NO3)3 14
5. Before dissolving the salts into distilled water 14
6. Solution of Ni(NO3)2 and Al2(NO3)3 14
7. Mixing of KOH into solution 14
8. Starting of precipitation 15
9. pH test 15
10. Filter cake 15
11. Filter cake into dryer 15
12. Calcined filter cake 15
13. Reactor gas flow meter 15
14. Fixed-bed reactor 16
15. Cylinder of H2 gas 16
16. Gas Chromatograph 16
17. Packed Column into GC 16
18. Methanation reaction setup 17
19. Gas chromatograph 17

5. 5
1. Theory:
1.1 Introduction to catalyst: By definition, catalyst is a chemical substance that fasten or
slow the rate of reaction but remains its original form and mass after reaction. There are many
categories of catalysts depending their activity on the reaction, their phase and their working
procedure. Catalysts are very important to us because sometimes without catalysts, some reactions
have very slow pace and it could be very harmful for us. Enzyme a biocatalyst, without its presence
many of our bio reactions would go at such a pace that is useless to us. Industries use catalysts so
that the reaction rate is increased.
1.2 Mechanism: Catalysts decrease the activation energy though it has no effect on the total
free energy of a reaction. [1] A catalyst may participate in multiple chemical transformations. The
effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons
(which reduce the catalytic activity) or promoters (which increase the activity and affect the
temperature of the reaction).[1 ] Catalyzed reactions have a lower activation energy (rate-limiting
free energy of activation) than the corresponding uncatalyzed reaction, resulting in a higher
reaction rate at the same temperature and for the same reactant concentrations.
Figure 01: Catalyst effect on activation energy
Catalyst can lower the activation energy by two procedures
1. It bonds with reactant to form an intermediate product then dissociates.

6. 6
2. It adsorbs reactant in it and lowers the bond energy between the reactant molecules
However, catalysts can only take the fastest way to reach equilibrium but it has no effect on
reaction equilibrium. The phase of the catalyst is very important for designing the reactor. If the
catalysts and reactants are in same phase, the catalyst is called to be homogenous. Otherwise, it is
named heterogeneous. For a heterogeneous catalyst, it is needed to increase the surface area. So ,
some improvements are suggested including the use of promoter, binder and support.
1.3Methanation Reaction: Methanation is a chemical reaction that converts carbon
monoxide and/or carbon dioxide to methane. The production of methane across the “Sabatier”
reaction is a well-known process for converting CO2to a useful product and was proposed by Paul
Sabatier and J.B. Sendersens in 1902. A large-scale production of methane on the basis of carbon
dioxide has never been widely established and on basis of carbon monoxide just in a few plants.
This is because of the up to date good availability and economy of natural gas. With the new
development of the Power to Gas technology for an energy-efficient storage solution of renewable
electricity, methanation gains a lot of importance.
CO2 + 4H2 ↔ CH4 + 2H2O ΔrH298 = -165 kJ/mol (1)
CO conversion to methane is described as
CO + 3H2 ↔ CH4 + H2O ΔrH298 = -206 kJ/mol (2)
Methanation is nowadays revamped in a lot of projects of syngas and carbon dioxide valorization.
However, for CO2-concentrated feed (with no dilution, the stoichiometric feed implies 20 % vol
of CO2and 80 % vol. of H2) the thermodynamic limitations appear to be very strong. The reaction
(1) is highly exothermal and the adiabatic temperature raise connected to the reaction progress is
quite high. For example the adiabatic equilibrium temperature of a stoichiometric CO2+ 4H2 feed
at 30 bar and 25°C would be 724°C. So the greatest challenge involved in methanation is the
temperature control of the exothermic reactions, meaning an efficient heat removal, which is
closely linked to reactor design. The adiabatic fixed bed reactor represents the simplest reactor
design option. The reactor is filled with catalytic pellets, and rather than being cooled its heat is
instead used to increase the gas temperature. With that increased temperature the reaction rate is

7. 7
very high and therefore requires a relative small amount of catalyst. As temperature increases the
chemical equilibrium of the methane formation process shifts towards the reactants and the
reaction comes to an equilibrium state at high temperatures which is not optimal for the CO2
conversion depending on the prevailing pressure. However the adiabatic temperature might need
to be limited to prevent catalyst destruction through thermal sintering. To limit the temperature
raise, the reactor feed gas can be diluted. Either with inert gas, a surplus of one reactant or product
gas recycle. For example reactor outlet gas can be recycled and shift the adiabatic temperature
raise towards lower temperatures.
1.4 Choice of catalysts:There are some catalysts which has been suggested and researched
for methanation reaction.
Rhodium: Using Alumina as support the steps leading to methane could be:
1. chemisorption of carbon dioxide;
2. dissociation of carbon dioxide into CO and O adsorbed on the surface;
3. reaction of dissociated species with hydrogen.
The oxidation state of the metal may also play an important role in the evolution of the reaction,
since CO2oxidizes the catalyst. Moreover, the production of methane depends upon the
temperature, pressure, presence, and absence of promoters. Obviously, when varying the Rh
content different metal particle sizes are formed, and at low temperatures (130–150 _C) the activity
of larger particle sizes of Rh was found to be higher than that of smaller ones. Furthermore, the
addition of Ba and K on the Al2O3 support allows significant differences in the catalytic behavior
in the temperature range 300–700 _C. CH4 was preferentially formed below 500 _C on Ba-
containing and pure Rh/Al2O3 while, at higher temperatures, significant amounts of CO were
formed.
Ruthenium: Ru is one of the most active methanation catalysts. Its catalytic activity and selectivity
to CH4 are, however, largely dependent on the dispersion of the metallic phase (at high dispersion
the apparent activation energy reaches a minimum), on the type of the support, and an addition of
modifiers/promoters that can more or less chemically interact with the metal.
Palladium: A good catalytic performance has also been observed with Pd-based catalysts.Pd is
able to dissociate molecular hydrogen and makes available hydrogen atoms for the subsequent
transfer and reaction with activated surface carbonate species formed by the reaction of CO2on a
Mg-containing oxide with the aim of providing a pathway to minimize CO formation by using

8. 8
metal oxides that inhibit CO desorption. Intermixed Pd and Mg sites are obtained by using the
reverse microemulsion synthesis route; 95% selectivity to CH4 and 59% CO2 conversion have
been measured at 450 degree. More recently, shape-controlled Pd nanoparticles embedded in
mesoporous silica have been tested in the reaction; their performance has been compared with a
Pd/SiO2catalyst prepared by wet impregnation. The encapsulation was demonstrated to have a
better stability towards sintering. Moreover, the different exposed facets of the metal demonstrated
different activities and selectivities for the CO2 methanation.
Nickel-Based Catalysts: Supported Ni catalysts are the most widely investigated materials for
CO2methanation due to their high efficiency in CH4 production and low cost. A lot of supports
have been investigated for Ni catalysts since, as is well known, the catalytic performance strongly
depends upon the nature and properties of the support. Its influence can be generally linked
tophysico-chemical peculiarities:
(i) varying the dispersion of the active phase;
(ii) (ii) modifying the reducibility of the oxide precursors by
tuning the interaction between the active phase and the support.
Alumina-Supported Nickel
The Ni/Al2O3 catalyst shows a high catalytic activity, although it suffers from severe carbon
deposition or poor stability due to the high reaction temperature used. Therefore, the aim
throughout the years was to develop catalysts able to show both high activity and resistance to
carbonaceous deposits in the reaction. So, since the pioneering work of Trimm et al., a lot of papers
have been published on the argument. We will examine here only the most recent ones, since the
number of studies covering the topic is huge, and other previous reviews can easily be found in
the literature. Rahamani et al. have prepared, by impregnation, a series of Ni catalysts supported
on mesoporous nanocrystalline -Al2O3, having high surface area and different Ni contents.
1.5 Preparation details
A method for preparing catalysts by precipitation is provided, which consists of the sequential
steps of
(a) preparing an aqueous solution of a nickel salt and aluminum salt in at least partly dissolved
state,
(b) precipitating substantially all metal ions from said aqueous solution by the addition of a base,

9. 9
(c) isolating and drying and precipitated metal compounds mixed with any undissolved compounds
present in the system formed in step (b),
(d) converting the thus-formed mixture of compounds into a mixture of the corresponding oxides
by calcination at temperatures between 300°C and 500°C,
(e) working the thus formed oxides mixture up into particles of any desired shape and size.
The catalyst is prepared by precipitating compounds of aluminum and nickel from an aqueous
solution containing ions of these metals. We used aluminium and nickel for catalyst preparation.
The detail of making the catalyst is in methodology section.
1.6 Gas Chromatography:
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for
separating and analyzing compounds that can be vaporized without decomposition. Typical uses
of GC include testing the purity of a particular substance, or separating the different components
of a mixture (the relative amounts of such components can also be determined). In some situations,
GC may help in identifying a compound. In preparative chromatography, GC can be used to
prepare pure compounds from a mixture
Figure 02: Setup of a Gas Chromatography
In gas chromatography, the mobile phase (or "moving phase") is a carrier gas, usually an inert
gas such as helium or an unreactive gas such as nitrogen. Helium remains the most commonly
used carrier gas in about 90% of instruments although hydrogen is preferred for improved

10. 10
separations. The stationaryphase is a microscopic layer of liquid or polymer on an inert solid
support, inside a piece of glass or metal tubing called a column (an homage to the fractionating
column used in distillation). The instrument used to perform gas chromatography is called a gas
chromatograph (or "aerograph", "gas separator").
The gaseous compounds being analyzed interact with the walls of the column, which is coated
with a stationary phase. This causes each compound to elute at a different time, known as the
retention time of the compound. The comparison of retention times is what gives GC its
analytical usefulness.
Gas chromatography is in principle similar to column chromatography (as well as other forms of
chromatography, such as HPLC, TLC), but has several notable differences. First, the process of
separating the compounds in a mixture is carried out between a liquid stationary phase and a gas
mobile phase, whereas in column chromatography the stationary phase is a solid and the mobile
phase is a liquid. (Hence the full name of the procedure is "Gas–liquid chromatography",
referring to the mobile and stationary phases, respectively.) Second, the column through which
the gas phase passes is located in an oven where the temperature of the gas can be controlled,
whereas column chromatography (typically) has no such temperature control. Finally, the
concentration of a compound in the gas phase is solely a function of the vapor pressure of the
gas.
Gas chromatography is also sometimes known as vapor-phase chromatography (VPC), or gas–
liquid partition chromatography (GLPC). These alternative names, as well as their respective
abbreviations, are frequently used in scientific literature.
1.7 Instrumental components
Carrier gas
The carrier gas must be chemically inert. Commonly used gases include nitrogen, helium, argon,
and carbon dioxide. The choice of carrier gas is often dependent upon the type of detector which
is used. The carrier gas system also contains a molecular sieve to remove water and other
impurities.
Sample injection port: For optimum column efficiency, the sample should not be too large, and
should be introduced onto the column as a "plug" of vapour - slow injection of large samples
causes band broadening and loss of resolution. The most common injection method is where a
microsyringe is used to inject sample through a rubber septum into a flash vapouriser port at the

11. 11
head of the column. The temperature of the sample port is usually about 50°C higher than the
boiling point of the least
volatile component of the sample. typically around 10-3mL. For capillary GC, split/splitless
injection is used.
Figure 03: Injector in different modes
The injector can be used in one of two modes; split or split less. The injector contains a heated
chamber containing a glass liner into which the sample is injected through the septum. The carrier
gas enters the chamber and can leave by three routes (when the injector is in split mode). The
sample vaporizes to form a mixture of carrier gas, vaporized solvent and vaporized solutes. A
proportion of this mixture passes onto the column, but most exits through the split outlet. The
septum purge outlet prevents septum bleed components from entering the column.
Columns: There are two general types of column, packed and capillary (also known as open
tubular). Packed columns contain a finely divided, inert, solid support material (commonly based
on diatomaceous earth) coated with liquid stationary phase. Most packed columns are 1.5 - 10m
in length and have an internal diameter of 2 - 4mm.
Capillary columns have an internal diameter of a few tenths of a millimeter. They can be one of
two types; wall-coated open tubular (WCOT) or support-coated open tubular (SCOT). Wall coated

12. 12
columns consist of a capillary tube whose walls are coated with liquid stationary phase. In support-
coated columns, the inner wall of the capillary is lined with a thin layer of support material such
as diatomaceous earth, onto which the stationary phase has been adsorbed. SCOT
columns are generally less efficient than WCOT columns. Both types of capillary column are
more efficient than packed columns.
TCD gas chromatography
A universal detector and can detect air, hydrogen, carbon monoxide, nitrogen, sulfur oxide,
inorganic gases and many other compounds.
Thermal conductivity (TCD) is a commonly used detector in gas chromatography. TCD works by
having two parallel tubes both containing gas and heating coils. The gases are examined by
comparing the heat loss rate from the heating coils into the gas. Normally one tube holds a
reference gas and the sample to be tested is passed through the other. Using this principle, a TCD
senses the changes in the thermal conductivity of the column effluent and compares it to a reference
flow of carrier gas. Most compounds have a thermal conductivity much less than that of the
common carrier gases of hydrogen or helium. Therefore, when an analyte elutes from the column,
the thermal conductivity of the effluent is reduced and a detectable signal is produced.
Helium has traditionally been the favoured carrier gas but as laboratory trends change, Linde is
also, able to offer hydrogen as an alternative to helium as a carrier gas for GC-TCD applications.
While flame ionization detector (FID) can provide very good resolution, TCD is a good general
purpose detector for initial investigations with an unknown sample, as it responds to all
compounds, thanks to the fact that all compounds, organic and inorganic, have a different thermal
conductivity from helium. The TCD is also used in the analysis of permanent and inorganic gases
(for example argon, oxygen, nitrogen, carbon dioxide, carbon monoxide, sulfur dioxide) because
it responds to all these substances unlike the FID, which cannot detect compounds which do not
contain carbon-hydrogen bonds.

13. 13
2. Experimental Section
Materials
1. Nickel nitrate (Ni(NO3)2)- 6.23gm;
2. Aluminum nitrate (Al(NO3)3)- 47.08gm;
3. Potassium hydroxide (KOH)- 7N;
4. H2 gas and
5. N2 gas as inert.
Experimental Method
First stage: Catalyst preparation
 Required amount of Ni(NO3)2 had been weighed and then dissolved in distilled water to
prepare a solution.
 Stirring the solution had been started. 7N KOH solution was being added slowly until the
pH of the solution had become 7.
 The precipitate was allowed to settle. Filtered to separate the solid. Washed with water to
remove impurities.
 The filter cake had been dried. The dry filter cake had been calcined 350oC for 3 hours
under atmospheric pressure.
 The calcined catalyst had been crushed. The hand press was used to form pellets of the
catalyst.
Second stage: Catalyst activation and performance study
 The catalyst had been loaded in the tubular reactor.
 The catalyst was being activated using a mixture of H2 and N2.
 After the activation was over, introducing the feed gas was started through the catalyst
bed.
 The outlet gas was collected in a gas sampling gas. A gas chromatograph was used to
analyze the outlet gas.

14. 14
Fig 05: Before dissolving the salts
into distilled water
Fig 06: Solution of Ni(NO3)2 and
Al2(NO3)3
Fig 07: mixing of KOH into
solution
Fig 04: Weighing the Ni(NO3)2
and Al2(NO3)3

15. 15
Fig 10: Filter cakeFig 09: pH testFig 08: starting of
precipitation
Fig 13: Reactor gas flow meterFig 12: Calcined filter cakeFig 11: Filter cake into dryer

16. 16
Fig 15: Cylinder of H2 gasFig 14: Fixed-bed reactor
Fig 16: Gas Chromatograph Fig 17: Packed Column into GC

17. 17
Experimental Setup
Figure 18: Methanation reaction setup
Figure 19: Gas chromatograph

18. 18
Process Block Diagram

19. 19
Observed Data:
 Basis:8 gm (Catalyst weight)
 Catalyst Activation: Mass of catalyst loaded=3.1002 gm
N2 flow = 20L/hr
H2 flow = 10L/hr
Reactor Condition: Temperature=350°C
Pressure = 2 bar
N2 flow = 20L/hr
H2 flow = 10L/hr
 Feed Condition:
Room Temperature = 32°C
Flow of N2= 20 L/hr, N2 Cylinder Pressure = 35 bar
Flow of H2 = 24 L/hr, H2 Cylinder Pressure = 90 bar
Flow of CO = 8 L/hr, CO Cylinder Pressure = 70 bar
 Outlet Condition:
Flow rate = 450 cm3/min, Sampling time = 12min
Operating Condition:
Vapor pressure of water 320C = 35.663 mm Hg
Table 01: Gas chromatography test data.
Components Standard Area
Standard Molar
Composition (%)
Sample Data Area
H2 315 48.27 354
N2 58207 31.80 64630
CH4 6028 8.37 2167
CO 6074 6.13 1103
CO2 1540 1.40 976

20. 20
Calculated Data:
Required weight of Al(NO3)3∙ 9H2O = 47.08 gm
Required weight of Ni(NO3)2∙ 6H2O = 6.23 gm
Inlet gas molar flow rate
N2 = 1.580 g-mole/hr
H2= 1.899 g-mole/hr
CO = 0.633 g-mole/hr
Dry gas flow at NTP = 2.085gm-mole/hr
Table02: Outlet gas composition (mole %) from GC (dry basis)
Species Composition (mole %)
H2 57.36
N2 37.34
CH4 3.18
CO 1.17
CO2 0.95

21. 21
Table03: Outlet gas flow rate (gm-mole/hr) from GC
Species Flow rate (gm-mole/hr)
H2 1.1960
N2 0.7785
CH4 0.0663
CO 0.0229
CO2 0.0198
Conversion of CO = 96.38% (mole)
Selectivity of CH4 to CO2 = 3.348
Sample Calculation:
a. Calculation for Catalyst Properties
Basis: 8 gm of Catalyst compound
Ratio: NiO: Al2O3 = 1:4
Amount of NiO in catalyst =
1×8
5
= 1.6 gm
Amount of Al2O3 in catalyst =
4×8
5
= 6.4 gm
Determination of the amount of Ni(NO3)2 ∙ 6H2O
Reaction: Ni(NO3)2 + KOH = Ni(OH)2 + 3KNO3
Ni(OH)2 = NiO + H2O
Required weight of Ni(NO3)2∙6H2O =
290.81×1.6
74.71
=6.23 gm
Determination of the amount of Al(NO3)3 ∙ 9H2O
Reaction: Al(NO3)3 + 3KOH = Al(OH)3 + 3KNO3

22. 22
2Al(OH)3 = Al2O3 + 3H2O
 Required weight of Al(NO3)3 ∙ 3H2O =
375.13×2×6.4
102.0
= 47.08 gm
Amount of 7N KOH =76 mL
b. Performance Evaluation of Synthesized Nickel-Alumina Catalyst
Inlet gas flow rates:
H2 =
22.4L760mmHg305K
mole.1gm1500mmHg273KL/hr24


= 1.899 g-mole/hr
N2 =
22.4L760mmHg305K
mole.1gm1500mmHg273K20L/hr


= 1.580 g-mole/hr
CO =
22.4L760mmHg305K
mole.1gm1500mmHg273KL/hr8


= 0.633 g-mole/hr
Outlet gas flow rates:
Gas flow rates = 450 cm3/min = 27.0 L/hr =
27×273×1500×1
305×760×22.4
= 2.136 g-mole/hr
Dry gas flow rate:
Dry gas flow rate at NTP =
2.136×(1500-35.663)
1500
g-mole/hr
=2.085 g-mole/hr
Outlet gas composition mole% from GC data
H2 =
354
315
× 48.27 = 54.25 mole
N2 =
64630
58207
× 31.80 = 35.31 mole
CH4 =
2167
6028
× 8.37 = 3.01 mole
CO=
1103
6074
× 6.13 = 1.11 mole

23. 23
CO2 =
976
1540
× 1.40 = 0.89 mole
Total mole =94.57 mole
After normalizing, in 100% (Dry Basis)
H2 =
54.25
94.57
× 100% = 57.36%
N2=
35.31
94.57
× 100% = 37.34%
CH4 =
3.01
94.57
× 100% = 3.18%
CO =
1.11
94.57
× 100% = 1.17%
CO2 =
.89
94.57
× 100% = 0.95%
Outlet gas flow rate from GC data at NTP (in gm-mole/hr)
H2 = 0.5736 × 2.085=1.1960 g-mole/hr
N2 = 0.3734 × 2.085 = 0.7785 g-mole/hr
CH4 = 0.0318 × 2.085= 0.0663 g-mole/hr
CO = 0.0110 × 2.085 = 0.0229 g-mole/hr
CO2 = 0.0095 × 2.085 = 0.0198 g-mole/hr
Conversion (mole %) =
in
outin
)(CO
)(CO)(CO 
=
0.633-0.0229
0.633
×100% = 96.38%
Selectivity 
2
4
CO
CH
ProductUndesired
ProductDesired 0.0663
0.0198
= 3.348

24. 24
Results and Discussions:
Conversion of CO is 96.38% (mole) in presence of the catalyst and the selectivity of CH4 to CO2
is 3.348 inside the tubular reactor.
The hydrogenation of carbon mono-oxides to methane are known as Methanation reactions:
CO + 3H2 = CH4 + H2O
CO2 + 4H2 = CH4 + 2H2O
Methanation is considered as an essential step in the production of Synthetic Natural Gas (SNG)
from coal and other solid fuels. Catalyst required for methane synthesis depends on composition
and method of preparation. Despite continued research on catalyst development, nickel had since
been the major catalyst for the reaction because of its high activity, selectivity for methane
formation and low cost.
Nickel catalyst used commercially for methanation are usually applied in supported form,
generally on alumina. The reactions that take place during the process are –
Co- precipitation: Ni(NO3)2 + 2KOH = Ni(OH)2 + 2KNO3
Al(NO3)3 + 3KOH = Al(OH)3 + 3KNO3
Calcination: Ni(OH)2   C350
NiO + H2O
2Al(OH)3   C350
Al2O3 + 3H2O
Reduction: NiO + H2   C250
Ni + H2O, ΔH⁰ = -0.8 kcal/ mole
Co-precipitation method was used to prepare the catalyst for our experiment. The intimate
interactions fostered by co- precipitation are believed to import improvements in activity and
stability to the nickel crystallites. But the mechanical strength is lower. It may also be possible that
irreducible compounds of NiO-Al2O3 are produced by co-precipitation. Calcinations are further
heat-treatment beyond drying and are usually accompanied by thermal conversions of the
reactants. Calcination of co-precipitated oxides initiates solid state reactions in addition to those
given for single oxides. In this case nickel-aluminate is formed.
The characteristics of an ideal support are –
 Available in large quantities of uniform composition
 Stable under operating and regeneration conditions.
 Resistant to attrition
 Sufficiently porous to permit dispersion of catalyst on its interior surfaces

25. 25
 No catalytic activity that leads to undesirable side reactions
 Strong enough to resist any thermal or mechanical shocks.
The reaction rate was not calculated because of the unavailability of adequate data which would
have given a far better knowledge about the influence of catalyst composition on the reaction rate.
Here, conversion of CO was 96.38% i.e. the catalyst converts most of the CO to CH4. The
environment of catalyst preparation & its activation influences its efficiency & thus conversion of
CO.
Selectivity of CH4 to CO2 was 3.348; it seems that the catalyst we used was not as selective in
producing methane as it could be. For an industrially suitable catalyst, both activity and selectivity
should be considered as major criteria.
Some of the other major features of the experiment are discussed below-
pH of the co-precipitating solution: The pH of the solution plays a critical role in
maintaining the final quality of the catalyst. If the pH crosses 7.0 and excess KOH is present it
coats the precipitates with itself and thus reduces the exposed surface, thereby significantly
reducing performance. If such an event does occur that the pH cross 7.0 then the precipitant must
be cleaned thoroughly before drying.
Catalyst Deactivation: Catalyst deactivation is an important study in any catalytic reaction.
The rates at which catalyst deactivation processes take place may be fast or slow.
Use of H2 as a reducer: In order to obtain nickel catalyst nickel oxide was reduced to nickel
by hydrogen.
NiO2 (inactive) + H2 = Ni (activated) + H2O
The process was done with N2 filling the rest of the space as O2 must be kept away from the freshly
activated catalyst or else it will be oxidized back to its previous form.
Use of silica gel in the experiment: Silica gel was used twice in this experiment.
Methanation reaction is inhibited by water, so feed gas should be free of water. After the feed gas
passes through Pad catalysts, it is passed through a silica gel bed to remove any water present in
the feed gas. Water is a product of Methanation reaction, this water must be removed before sample
is taken for gas chromatography analysis. Most of the water is removed in the condenser; the small
amount of water that may be present is adsorbed by the silica gel.
Use of H2 gas as process fluid: Hydrogen is a reactant in Methanation reaction. H2 was fed
in excess of stoichiometric amount.

26. 26
i. If the deactivation is rapid and caused by the decomposition or degradation or
reactants or products on the catalyst surface, the process is termed fouling. In this
case a deposit is formed on the surface or in the pores that physically blocks a
portion of the catalyst and prevents it from catalyzing the reaction.
ii. If the activity of the catalyst is slowly modified by chemisorption of materials that
are not easily removed, the deactivation process is termed poisoning. Catalyst
poisons may be classified in terms of the manner by which the poison affects
chemical activity.
1. Selectivity Poisons: These poisons decrease the selectivity of the catalyst for the
main reaction. In many cases impurities in the feed stream will adsorb on the
catalyst surface and then act as catalysts for undesirable side reactions.
2. Diffusion Poisons: The phenomenon is closely similar to catalyst fouling. Blockage
of pore mouths prevents full use of the interior surface area of the pellet. Entrained
dust particles or materials that can react on the catalyst to yield a solid residue give
rise to this type of poisoning.
3. Intrinsic ActivityPoisons: These poisons decrease the activity of the catalyst for the
primary chemical reaction by virtue of their direct electronic or chemical influence
on the catalyst surface or active sites.
4. Stability Poisons: These poisons decrease the structural stability of the catalytic
agent or of the carrier by facilitating recrystallization and other structural
rearrangements.
iii. Two main phenomena contributing to the Ni based catalyst deactivation are-
a. metal sintering
b. Carbon deposition (Carbon formation blocks the active site of Ni surface)
Both of them make catalyst less porous and more crystalline. Also, Aluminate phase
formation might be one of the reasons beside catalyst deactivation behind low rate of
conversion.
Use of Nitrate salts: Nitrate salts were taken because they are easily decomposed to give
oxides of desired metals. Sulfate salt cannot be used as they are stable in nature. Since sulfur acts
as poison so we try to avoid sulfur compounds as much as possible.

27. 27