Production of synthesis gas from natural gas by reforming process

1. Course Title: Project
Course Code: ACCE 408
Submitted By
Md. Habibur Rahman
Student ID:
20121107042
Session: 2012-2013
4th Year 1st Semester
Submitted To
Dr. Md. Nurunnabi
Assistant Professor
Applied Chemistry and
Chemical Engineering
Department of Applied Chemistry and Chemical
Engineering Faculty of Engineering

2. My Presentation topic
is
Production of synthesis gas from natural
gas
by reforming process

3.  Syngas (synthesis gas) is a mixture of H2 and CO is
produced by the steam reforming and partial oxidation of
hydrocarbons or a combination of both processes.
 It is also called as coal bedded methane gas. Syngas is
the condensation for Synthesis gas.
 The name syngas is derived from the use as an
intermediate in generating synthetic natural gas and to
create ammonia or methanol.
 Syngas main products:
 Fuel gas (C1-C2)
 Gasoline
 Kerosene
 Jet Fuel
 Diesel
 Soft and Hard Wax

4.  The syngas contain-
 30 to 60% CO, carbon monoxide
 25 to 30% hydrogen (H2),
 0 to 5% methane (CH4),
 5 to 15% carbon dioxide (CO2),
 A lesser or greater amount of water vapor,
 smaller amounts of the sulfur compounds hydrogen sulfide (H2S),
carbonyl sulfide (COS),
 Finally some ammonia and other trace contaminants

5. There are seven reforming processes available for the production of
syngas from natural gas, whose major component is methane. These
are-
 Steam Reforming (SMR),
 Partial Oxidation (POX),
 Auto Thermal reforming, (ATR),
 Dry Reforming of methane (DMR),
 Combined Reforming of methane (CMR),
 Reforming with Membrane,
 Tri-reforming of Methane (TMR).

6.  Steam reforming or steam methane reforming (SMR) is the reaction
where steam and hydrocarbons, such as natural gas or refinery feed
stock, react in a reformer at temperature of 800˚C - 900˚C and
moderate pressure in the presence of metal based catalyst for the
production of syngas .
 Syngas reacts further to give more hydrogen and carbon dioxide via
the water gas shift reaction, which is a side reaction in steam
reforming. Steam reforming of natural gas produces syngas with a
H2:CO molar ratio close to 3.

7.  Partial oxidation is an exothermic reaction and, thus, considered
more economic than the processes of steam reforming or dry
reforming, because it requires a smaller amount of thermal energy.
 On the other hand, the partial oxidation is considered an expensive
process because it requires a flow of pure oxygen.
 In non-catalytic partial oxidation, the production of syngas depends
on the air-fuel ratio at operating temperature of 1200˚C - 1500˚C
without a catalyst .
CH4 +1/2 O2 = CO+H2

8.  The purpose of the auto-thermal reforming is the production of syngas.
 By proper adjustment of oxygen to carbon and steam to carbon
ratios, the partial combustion in the thermal zone supplies the heat
for completing the subsequent endothermic steam and CO2
reforming reactions .
 The product gas composition at the exit of the reactor results very
close to the thermodynamic equilibrium of an adiabatic reactor

9.  In Dry Reforming CO2 can be used in place of steam for
reforming.CO2 reforming of methane shows significant environmental
and economic benefits by consuming two major greenhouse gases,
carbon dioxide and methane to produce synthesis gas .
 It offers advantages such as the production of syngas with a lower
H2 /CO ratio and it obviates a water vaporization step to produce
steam, an energy consumer process and eliminate CH4 and CO2.

10.  Combined steam and CO2 reforming of CH4 has attracted interest
from both industrial and environmental perspectives.
 Firstly, from an environmental point view, the two most abundant
carbon containing greenhouse gases, methane and carbon dioxide,
can be utilized effectively in this reaction and converted into useful
chemical products.
 Secondly, from an industrial perspective, the reaction produces
syngas (H2/CO) with a ratio about 2, which is suitable for Fischere-
Tropsch and methanol synthesis.
 Steam reforming reaction:
CH4 + H2O → CO + 3H2

11.  Carbon dioxide reforming of methane produces synthesis gas with a
low hydrogen to carbon monoxide ratio, which is desirable for many
industrial synthesis processes.
 This reaction also has very important environmental implications
since both methane and carbon dioxide contribute to the greenhouse
effect. Converting these gases into a valuable feedstock may
significantly reduce the atmospheric emissions of CO2 and CH4.
 Natural gas mainly contains methane, but also ethane; propane,
butane and even higher hydrocarbons. It is converted into H2,CO.
 Carbon dioxide reforming:
CH4 + CO2 → 2CO + 2H2

12.  Catalytic partial oxidation is an exothermic reaction, so it tends to
form hot spots in catalyst beds. It is difficult to control, particularly in
a large scale operation .
 The process of combination of CO2 reforming and partial oxidation
of methane to produce syngas couples the advantages of DMR and
POX .
 The following advantages:
1) Energy coupling,
2) Controllable product ratio of H2/CO according to the
need of the post-process,
3) A safer operating environment.

13.  Generally, the catalysts used for the reforming reactions are
categorized into two groups:
1)Supported noble metals, and
2)Non-noble transition metals.
 There has been extensive research work on steam reforming,
catalytic partial oxidation and dry reforming catalysts including
rhodium , ruthenium [and platinum, Palladium , Iridium , catalysts.

14.  Steam reforming catalysts are almost always based on nickel as the
active metal on a ceramic carrier such as Al2O3 or MgAl2O4.
 The very high temperatures in the ATR require the installed catalyst
has excellent thermal stability.
 ATR catalysts is the development of high pressure drops across the
catalyst bed.

15.  The process uses steam methane to reform a hydrocarbon feed in
catalyst-filled tubes heated by a top-fired furnace.

16.  Autothermal Reforming (ATR) is a process for producing syngas,
composed of hydrogen and carbon monoxide, by partially oxidizing a
hydrocarbon feed with oxygen and steam .
 The pre-reformer widens the range of hydrocarbons suitable for
reforming. It also takes over some duty from the primary reformer,
inorder that it can operate under less severe conditions.

17.  The feedstock for ATR can be natural gas, refinery off gas, pre-
reformed gas, Fischer Tropsch tail-gas, Liquefied Petroleum Gas
(LPG) or naphtha.
 In the first reaction step, the feed gas reacts with oxygen (partial
combustion) and steam to produce syngas. This gas mixture enters
then, inside the same reactor, a catalyst bed for further reforming in
order to achieve a high yield reaching thermodynamic equilibrium.
 The syngas can be used as feedstock for various synthesis
processes, mainly methanol and Fischer-Tropsch synthesis.

19. 1. Natural gas:
2. Wood Biomass

21.  The synthesis gas, produced by the reaction, has a high CO content
which is effective for the synthesis of valuable oxygenated
chemicals.
 Nickel based catalysts and noble metal-supported catalysts (Rh, Ru,
Pd, Pt,) were found to have promising catalytic performance .
 The major source of synthesis gas, which is mainly used as natural
gas and Fischer Tropsch conversions, is from the steam reforming
reaction.

22.  The ATR reactor consists of a burner, a combustion chamber, and a
fixed catalyst bed within a refractory lined pressure shell. Natural gas
or a similar hydrocarbon feed is directed to the fuel side of the burner
inlet and oxygen to the oxidant side.
 In the combustion chamber, a large number of combustion reactions
proceed along with the steam reforming and shift reactions.
 The reaction takes place-

23.  A preheated mixture of natural gas, steam and oxygen is
fed through the top of the reactor. In the upper zone,
partial oxidation proceeds at a temperature of around
1200°C.
 After that, the mixture is passed through a catalyst bed,
where final reforming reaction takes place .The catalyst
destroys any carbon formed at the top of the reactor. The
outlet temperature of the catalyst bed is between 850
and 1050°C.

24.  Heat Exchange Reformers Basically, a heat exchange reformer is a
steam reformer where the heat required for the reaction is supplied
predominantly by convective heat exchange.
 The heat can be supplied from flue gas or process gas or in principle
by any other available hot gas.
Fig : Steam Reformer

25. Figure : Different types of heat
exchanger of steam reformer

27. Partial oxidation reactor

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569
5. De Groote, A. M. and G. F. Froment, “Simulation of the Catalytic
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