synthesis gas preparation first methane is cleaned to remove sulphur impurities that would poison...
TRANSCRIPT
Synthesis gas preparation
First methane is cleaned to remove sulphur impurities that would poison the catalysts.
The clean methane is then reacted with steam over a catalyst of nickel oxide. This is called steam reforming:
CH4 + H2O → CO + 3H2
Secondary reforming
addition of air to convert the methane that did not react during steam reforming.
2CH4 + O2 → 2CO + 4H2
CH4 + 2O2 → CO2 + 2H2O
Wikipedia
Haber Process
The synthesis of ammonia using an iron oxide catalyst:
At 15–25 MPa (150–250 bar)
between 300 and 550 °C,
passing the gases over four beds of catalyst, with cooling between each pass to maintain a
reasonable equilibrium constant.
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
3. H2 (g) → H2 (adsorbed)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
3. H2 (g) → H2 (adsorbed)
4. H2 (adsorbed) → 2H (adsorbed)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
3. H2 (g) → H2 (adsorbed)
4. H2 (adsorbed) → 2H (adsorbed)
5. N (adsorbed) + 3H (adsorbed)→ NH3
(adsorbed)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
3. H2 (g) → H2 (adsorbed)
4. H2 (adsorbed) → 2H (adsorbed)
5. N (adsorbed) + 3H (adsorbed)→ NH3
(adsorbed)
6. NH3 (adsorbed) → NH3 (g)
he reaction mechanism, involving the heterogeneous catalyst, is believed to be as follows:
1. N2 (g) → N2 (adsorbed)
2. N2 (adsorbed) → 2N (adsorbed)
3. H2 (g) → H2 (adsorbed)
4. H2 (adsorbed) → 2H (adsorbed)
5. N (adsorbed) + 3H (adsorbed)→ NH3
(adsorbed)
6. NH3 (adsorbed) → NH3 (g)
1.On each pass only about 15% conversion
2.unreacted gases are recycled
3.eventually overall conversion of 98%
The production of ammonium nitrate in industry although simple chemistry is technologically challenging:
The production of ammonium nitrate in industry although simple chemistry is technologically challenging:
The acid-base reaction of ammonia with nitric acid gives a solution of ammonium nitrate:[2]
The production of ammonium nitrate in industry although simple chemistry is technologically challenging:
The acid-base reaction of ammonia with nitric acid gives a solution of ammonium nitrate:[2]
HNO3 (aq) + NH3 (g) → NH4NO3 (aq).
The production of ammonium nitrate in industry although simple chemistry is technologically challenging:
The acid-base reaction of ammonia with nitric acid gives a solution of ammonium nitrate:[2]
HNO3 (aq) + NH3 (g) → NH4NO3 (aq).
anhydrous ammonia gas and concentrated nitric acid. This reaction is violent and very exothermic.
1. 100 million tons of nitrogen fertilizer per year
2. 3-5% of world natural gas production
1. 100 million tons of nitrogen fertilizer per year
2. 3-5% of world natural gas production
3. ~1-2% of the world's annual energysupply
1. 100 million tons of nitrogen fertilizer per year
2. 3-5% of world natural gas production
3. ~1-2% of the world's annual energysupply
4. sustains one-third of the Earth's population
1. 100 million tons of nitrogen fertilizer per year
2. 3-5% of world natural gas production
3. ~1-2% of the world's annual energysupply
4. sustains one-third of the Earth's population
5. environmental consequences.
The Haber process now produces 100 million tons of nitrogen fertilizer per year, mostly in the form of anhydrous ammonia, ammonium nitrate, and urea. 3-5% of world natural gas production is consumed in the Haber process (~1-2% of the world's annual energy supply)[1][13][14][15]. That fertilizer is responsible for sustaining one-third of the Earth's population, as well as various deleterious environmental consequences.[2][5] Generation of hydrogen using electrolysis of water, using renewable energy, is not currently competitive cost-wise with hydrogen from fossil fuels, such as natural gas, and is responsible for 4% of current hydrogen production. Notably, the rise of this industrial process led to the "Nitrate Crisis" in Chile, when the industrials who owned the nitrate mines (most of them British) left the country — since the natural nitrate mines were no longer profitable — closing the mines and leaving a large unemployed Chilean population behind.[edit] See also
The steam reforming, carbon dioxide removal and methanation operate at pressures of about 2.5–3.5 MPa (25–35 bar),
Synthesis gas preparationFirst, the methane is cleaned, mainly to remove sulphur impurities that would poison the catalysts.The clean methane is then reacted with steam over a catalyst of nickel oxide. This is called steam reforming:
CH4 + H2O → CO + 3H2
Secondary reforming then takes place with the addition of air to convert the methane that did not react during steam reforming.
2CH4 + O2 → 2CO + 4H2CH4 + 2O2 → CO2 + 2H2O
Synthesis gas preparationFirst, the methane is cleaned, mainly to remove sulphur impurities that would poison the catalysts.The clean methane is then reacted with steam over a catalyst of nickel oxide. This is called steam reforming:
CH4 + H2O → CO + 3H2
Secondary reforming then takes place with the addition of air to convert the methane that did not react during steam reforming.
2CH4 + O2 → 2CO + 4H2CH4 + 2O2 → CO2 + 2H2O
There are many engineering and construction companies that offer proprietary designs for ammonia synthesis plants. Haldor Topsoe of Denmark, Lurgi AG of Germany, Uhde of Germany, Saipem/Snamprogetti of Italy and Kellogg, Brown and Root of the United States are among the most experienced companies in that field.[7]
Nowadays, the bulk of the hydrogen required is produced from methane (natural gas) using heterogeneous catalysis, because this requires far less external energy input compared to the electrolysis of water. However, the source of the hydrogen makes no difference to the Haber-Bosch process, which is only concerned with synthesizing ammonia from nitrogen and hydrogen.
Nowadays, the bulk of the hydrogen required is produced from methane (natural gas) using heterogeneous catalysis, because this requires far less external energy input compared to the electrolysis of water. However, the source of the hydrogen makes no difference to the Haber-Bosch process, which is only concerned with synthesizing ammonia from nitrogen and hydrogen.
png - en.citizendium.org/images/6/6a/Steam-Methane
age at: www.initrogen.org/fileadmin/timeline/1913.html
Then the water gas shift reaction yields more hydrogen from CO and steam.
CO + H2O → CO2 + H2
The gas mixture is now passed into a methanator, which converts most of the remaining CO into methane for recycling:
CO + 3H2 → CH4 + H2O
This last step is necessary as carbon monoxide poisons the catalyst. The overall reaction so far turns methane and steam into carbon dioxide, steam, and hydrogen.
Reaction 5 occurs in three steps, forming NH, NH2, and then NH3. Experimental evidence points to reaction 2 as being the slow, rate-determining step.
A major contributor to the elucidation of this mechanism is Gerhard Ertl.[9][10][11][12]
he chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NH4NO3, is a white powder at room temperature and standard pressure. It is commonly used in agriculture as a high-nitrogen fertilizer, and it has also been used as an oxidizing agent in explosives, including improvised explosive devices.Ammonium nitrate, when mixed with water, will create a cold substance that can be used as a cold pack.
The processes involved in the production of ammonium nitrate in industry, although simple in chemistry, challenge technology: The acid-base reaction of ammonia with nitric acid gives a solution of ammonium nitrate:[2] HNO3(aq) + NH3(g) → NH4NO3(aq).
For industrial production, this is done using anhydrous ammonia gas and concentrated nitric acid. This reaction is violent and very exothermic.
After the solution is formed, typically at about 83% concentration, the excess water is evaporated to an ammonium nitrate (AN) content of 95% to 99.9% concentration (AN melt), depending on grade. The AN melt is then made into "prills" or small beads in a spray tower, or into granules by spraying and tumbling in a rotating drum. The prills or granules may be further dried, cooled, and then coated to prevent caking. These prills or granules are the typical AN products in commerce.
The Haber process combines nitrogen and hydrogen to produce ammonia, part of which can be oxidised to nitric acid and combined with the remaining ammonia to produce the nitrate. Another production method is used in the so-called Odda process.