Episode 3 : Production of Synthesis Gas by Steam Methane Reforming
History of Synthesis Gas
In 1780, Felice Fontana discovered that combustible gas develops if water vapor is passed over carbon at temperatures over 500 °C. This CO and H2 containing gas was called water gas and mainly used for lighting purposes in the19th century.
As of the beginning of the 20th century, H2/CO-mixtures were used for syntheses of hydrocarbons and then, as a consequence, also called synthesis gas.
Haber and Bosch discovered the synthesis of ammonia from H2 and N2 in 1910 and the first industrial ammonia synthesis plant was commissioned in 1913.
The production of liquid hydrocarbons and oxygenates from syngas conversion over iron catalysts was discovered in 1923 by Fischer and Tropsch.
Much of the syngas conversion processes were being developed in Germany during the first and second world wars at a time when natural resources were becoming scare and alternative routes for hydrogen production, ammonia synthesis, and transportation fuels were a necessity.
In 1943/44, this was applied for large-scale production of artificial fuels from synthesis gas in Germany.
Episode 3 : Production of Synthesis Gas by Steam Methane Reforming
1. SAJJAD KHUDHUR ABBAS
Chemical Engineering , Al-Muthanna University, Iraq
Oil & Gas Safety and Health Professional – OSHACADEMY
Trainer of Trainers (TOT) - Canadian Center of Human
Development
Episode 3 : Production of
Synthesis Gas by Steam
Methane Reforming
2. History of Synthesis Gas
• In 1780, Felice Fontana discovered that
combustible gas develops if water vapor is passed
over carbon at temperatures over 500 °C. This CO
and H2 containing gas was called water gas and
mainly used for lighting purposes in the19th
century.
• As of the beginning of the 20th century, H2/CO-
mixtures were used for syntheses of hydrocarbons
and then, as a consequence, also called synthesis
gas.
3. • Haber and Bosch discovered the synthesis of ammonia from
H2 and N2 in 1910 and the first industrial ammonia synthesis
plant was commissioned in 1913.
• The production of liquid hydrocarbons and oxygenates from
syngas conversion over iron catalysts was discovered in
1923 by Fischer and Tropsch.
• Much of the syngas conversion processes were being
developed in Germany during the first and second world wars
at a time when natural resources were becoming scare and
alternative routes for hydrogen production, ammonia
synthesis, and transportation fuels were a necessity.
• In 1943/44, this was applied for large-scale production of
artificial fuels from synthesis gas in Germany.
4. To this day, however, methanol and
ammonia are still produced from
syngas using essentially the same
processes originally developed and,
apart from hydrogen production,
constitute the major uses of syngas.
5. What is synthesis gas ?
In its simplest form, syngas (also called producer gas, town
gas, blue water gas, and synthesis gas) is composed of carbon
monoxide (CO) and hydrogen (H2).The name comes from its
use.
Syngas is combustible and often used as a fuel of internal
combustion engines. It has less than half the energy density of
natural gas.
6. syngas can be produced from any hydrocarbon
feedstock, including: natural gas, naphtha, residual
oil, petroleum coke, and coal.
The lowest cost routes for syngas production,
however, are based on natural gas, the cheapest
option.
The choice of technology for syngas production
also depends on the scale of the synthesis
operation.
7. Syngas production from solid fuels can require an
even greater capital investment with the addition of
feedstock handling and more complex syngas
purification operations.
The syngas composition, most importantly the H2/CO
ratio, varies as a function of production technology and
feedstock.
Steam methane reforming yields H2/CO ratios of 3/1,
while coal gasification yields ratios closer to unity or
lower.
8.
9. Physical Properties of Hydrogen (H2):
With only one proton and one electron, hydrogen is the lightest of all chemical elements.
At ambient temperature, molecular hydrogen, H2, is a colourless and odorless gas.
hydrogen condenses to a colorless liquid, it freezes at –259.15 °C.
H2 is14 times lighter than air.
ValueUnitproperty
2.016g mol–1Molar mass
898J mol–1Heat of vaporization
Properties at 273.15 K, 101.3 kPa
0.0899kg m–3Density
0.1645W m–1 K–1Thermal conductivity
Cp = 22.0, Cv = 6.51J mol–1 K–1Molar heat
10. ValueUnitProperty
Boiling point (101.3 kPa)
20.37KTemperature
70.00kg m–3
Density (liquid)
1.319kg m–3Density (gas)
Liquid at boiling point (101.3 kPa)
Cp = 22.0, Cv = 6.51J mol–1 K–1Molar heat
–7918J mol–1Enthalpy
0.117W m–1 K–1Thermal conductivity
Gas at boiling point (101.3 kPa)
Cp = 23.49, Cv = 12.8J mol–1 K–1Specific heatcapacity
–7020J mol–1Enthalpy
0.0185W m–1 K–1Thermal conductivity
Critical Point
33.00KTemperature
1339kPaPressure
30.09kg m–3Density
11. Chemical properties of hydrogen
In air, H2 combusts to water with a hardly visible, weakly
bluish flame. Hydrogen combines with almost any other
element. Metal compounds with negatively charged
hydrogen are called metal hydrides (e.g. CaH2, NaH,
LiH).Hydrogen has a reducing effect on a lot of metal
oxides when heated. Thus CuO with H2, for example,
reacts to Cu and H2O. Hydrogen has a reducing
effect on a lot of metal oxides when heated.
12. Physical and Chemical Properties of Carbon
Monoxide (CO):
Carbon monoxide is colourless, odourless and tasteless. It is highly
toxic,poorly soluble in water (solubility: 23 mL L–1 at 20 °C and 1
bar).
ValueUnitProperty
28.010g mol–1Molar mass
10.9 – 76% Volume fractionExplosion range
(in air at 101.3 kPa)
Properties at 273.15 K, 101.3 kPa
1.250kg m–3Density
Cp = 29.05,Cv =
20.68
J mol–1 K–1Molar heat
0.02324W m–1 K–1Thermal conductivity
13. ValueUnitProperty
Boiling point (101.3 kPa)
81.65KTemperature
Melting point (101.3 kPa)
74.15KTemperature
Critical point
132.29KTemperature
3496KpaPressure
301kg m–3Density
14. Chemical properties of CO
Together with air, carbon monoxide forms explosive
mixtures in the concentration range of a CO-volume
fraction of (10.9-76%).In engineering, it is obtained by
separation from synthesis gas.
The reason for its toxicity is it’s property to displace the
oxygen from the hemoglobin-complex of blood, since the
affinity of hemoglobin (Hb) to CO is about 300 times
higher than to O2. The hemoglobin of a heavy smoker of
cigarettes can reach a CO-saturation of up to 15% in the
course of a day.
15. Uses of syngas
1. Syngas can be used to produce a variety of chemicals like
ammonia and methanol.
2. Syngas itself can be used as a fuel in internal combustion
engine.
3. Syngas is also used as an intermediate in producing synthetic
petroleum for use as a fuel or lubricant via the Fischer–
Tropsch process and previously the Mobil methanol to
gasoline process.
4. syngas can be used to produce organic molecules such as
synthetic natural gas (SNG-methane).
16. At these days, synthesis gas is mainly used for production of the
products listed:
UsesProduct
AmmoniaH2 and N2
Formic acidCO
Acetic acidH2 and CO
MethanolMixtures of (H2, CO and CO2)
17. Production of Synthesis Gas from Hydrocarbons:
In the production of synthesis gases from hydrocarbons, the
components hydrogen and carbon monoxide usually appear
as complementary products, carbon dioxide can be obtained
as a by-product.
There are Several Methods to Production the
Synthesis Gas from Hydrocarbons :
1.Steam Reforming
2.Partial Oxidation (PO ).
3.Autothermal Reforming ( ATR).
18. The Process Selection depends on Two factors:
1.The desired product composition (H2/CO ratio ).
2.The feedstock available like natural gas, residual gases
from refineries,LPG(Liquefied Petroleum Gas), naphtha,
heavy oils, distillation residues, pitch and coal.
The selected process in this project is Production
Synthesis Gas by steam reforming of Methane Gas due
to ratio (H2/CO)is equal to 3/1 and the feed is methane gas.
the economic cost of the steam must be taken into account
19. The Advantages of (SMR):
Steam reforming of natural gas are :
Efficient
Economical
widely used process for hydrogen and monoxide
production
provides near- and mid-term energy security and
environmental benefits
The SMR produces a H2/CO ratio equal to three
20. We choose methane as a feed because of :
• Methane is a wide distribution in nature.
• cheap
• Make a Less problems with the reformer.
• Make a longer age for reformer than other feed
stockes.
21. Methane
Methane is a chemical compound with the chemical formula CH4 (one atom
of carbon and four atoms of hydrogen). It is the simplest alkane and the main
component of natural gas.
Methane is a colorless, odorless gas with a wide distribution in nature. It is the
principal component of natural gas, a mixture containing about 75% CH4, 15%
ethane (C2H6), and 5% other hydrocarbons, such as propane (C3H8) and butane
(C4H10).
ValueUnitProperty
CH4Molecular formula
16.04g mol-1Molar Mass
0.656g cm-3Density at 25 °C , 1 atm
0.142mPa.sViscosity at -170 °C
5.34J g-1 k-1Specific heat capacity at
-100 °C
-182°CMelting point
43.4cm s-1Flame Velocity
23. Sources of Methane
Natural sources
1.Wetlands
2.Oceans
3.Geological sources
4.Wild animals
5.Wildfires
Non Natural sources
(Artificiality)
1.Oil and Gas System
2.Landfills
3.Wastewater
4.Coal Mines
5.Agriculture
24. Steam Reforming (Tubular Reforming)
Steam Reforming Methane (SMR) has been used for several decades since
it has been developed in 1926 and over the years substantial improvements
have been introduced. SMR process consists of gas feed pre-heating and
pre-treatment, reforming.
Steam reforming of methane is the main industrial route to produce
synthesis gas (a mixture of hydrogen and carbon monoxide).
In the steam reforming process, a light hydrocarbon feedstock (such as
natural gas, refinery gas, LNG, or naphtha) is reacted with steam at
elevated temperatures(typically 700° C to 900° C), and elevated pressures
(15 to 30 bar) in nickel-based catalyst filled tubes to produce a synthesis
gas. This gas consists primarily of hydrogen and carbon monoxide. , but
other gases such as carbon dioxide and nitrogen, as well as water vapor
are also present.The typical steam to carbon ratio falls in the range of (2.8
to 3.2 to 1).
25. steam reforming (SR) is highly endothermic and it is carried out at
high temperature (700 - 900 ºC) and at pressures between 15 and
30 bar.
26. The standard enthalpies of reaction (at 298 K) are given in brackets. The
most important reactions in steam reforming (SR) of methane are:
1. CH4(g) + H2O(g) ↔ CO(g) + 3H2(g) (∆H = +206 kJ/mol)
2. CO(g) + H2O(g) ↔ CO2(g) + H2(g) (∆H = -41 kJ/mol)
Reactions and thermodynamics
27. Catalyst
All tubular reformers use catalyst inside the
tubes in order to reduce the operating
temperature. This is important in order to
reduce the tube stresses resulting from high
pressure and high temperatures The Ni-catalyst
is needed since methane is a very
thermodynamically stable molecule even at
high temperatures. nickel catalyst filled tubes to
produce a synthesis gas.
Ni-catalyst is often in the form of thick-walled
Raschig rings, with 16 mm in diameter and
height, and a 6 – 8 mm hole in the middle.
28. Challenges
During the production of Synthesis gas, CO2 is
also produced. The SMR process in centralized
plants emits more than twice the CO2 than
hydrogen produced. To avoid emission of CO2
into the atmosphere, CO2 can be concentrated,
captured, and sequestered.