Production Of Syngas and Ethanol Group#4 Sara Al-Quhaim Mona Al-Khalaf Noura Al Dousari Sara Al Safi

Production Of Syngas and Ethanol

Group#4

Sara Al-QuhaimMona Al-Khalaf Noura Al Dousari

Sara Al Safi

Agenda:

• Introduction to syngas

• Steam Reforming of natural gas

• Partial Oxidation of natural gas

• Partial Oxidation of vacuum residue

• Introduction to Ethanol

• Ethanol Production Process

Introduction to syngas:

• gas mixture that contains different amounts of carbon monoxide (CO) and hydrogen. The ratio of hydrogen to carbon monoxide varies according to the type of feed, the method of production and the end use of the gas.

Production of Synthesis gas

using Steam Reforming

The production of syngas from methane can be realized by the following

three reactions:

CH4 +H2O → CO + 3H2 (1)

CH4 + CO2 → 2CO + 2H2 (2)

CH4 + 0.5O2 → CO + 2H2 (3)

The reactions are known as :

(1) steam reforming.

(2) CO2 reforming.

(3) partial oxidation reforming

• Process: Process for the preparation of hydrogen and carbon monoxide rich

gas by steam reforming of hydrocarbon feedstock in presence of a steam reforming catalyst supported as thin film on the wall of a

reactor, comprising steps of :

• Gas of hydrocarbon feedstock through a first reactor with a thin film of steam reforming catalyst supported on walls of the

reactor.

• Passing effluent from the first reactor to tubular reactor being provided with a thin film of steam reforming catalyst.

• Passing the effluent from the second reactor to an autothermal reformer.

• Withdrawing from the autothermal reformer a hot gas stream of product gas rich in hydrogen and carbon monoxide.

Flowsheet :

• Thermodynamics:

• The syngas production by steam mehane reforming is consisting of three reactions:

• CH4 + H2O + (heat) → CO + 3H2 (1)• CH4 + CO2 → 2CO + 2H2 (2) • CH4 + ½O2 → CO +2H2 +heat (3)

Process Conditions:

Feed Stocks (Raw Material):

1-Methane

2-Steam

3-Oxygen

Final products:

1- carbon monoxide

2- hydrogen

Production of Synthesis gas using partial oxidation of Natural gas:

• Partial oxidation:

• In partial oxidation process pure oxygen is used at elevated pressure and temperature as an oxidizer of the natural gas.

• The overall reaction describing the process is:

• In this exothermic reaction the ratio of (H2/CO=2) and This ratio of (H2/CO) from partial oxidation is lower than from steam reforming. The reaction is usually operated at high temperature (1200-1500 ºC) and pressure (20-150 bar).

Production of Synthesis gas using partial oxidation of Natural gas:

• The steps of partial oxidation process:

– Preheated natural gas and oxygen are fed to the reactor. They are mixed by a burner and react in a turbulent diffusion flame. The reactor is refractory lined to sustain the high temperatures of the produced syngas (1,650 K).

In comparison to the steam reforming method,

the reactor is simple. Another distinguishing

characteristic of the partial oxidation method

is that energy consumption is low because

the reaction is exothermic .

Production of Synthesis gas using partial oxidation of Natural gas:

• The catalytic partial oxidation:

• The catalytic partial oxidation reaction route consists of:

1. Direct route.

2. Two-stage route.

Production of Synthesis gas using partial oxidation of Natural gas:

• Direct route:• In the direct route, carbon gas and hydrogen are produced directly

from methane.

– Reactor used in the direct route catalyst:1. Research with fixed bed reactor

2. Monolith type reactor

3. Fluid bed reactor

• Two-stage route:• In the two-stage route, complete combustion of methane

takes place at first, then synthetic gas is produced by subsequent steam reforming, carbon gas reforming, or by the advance of a shift reaction.

Production of Synthesis gas using partial oxidation of Natural gas:

• In order to compensate for the defects of these methods and reduce the costs of producing natural gas, a compound reforming method and an automatic-thermal reforming method are being developed.

• Autothermal Reforming (ATR):

• This process combines partial oxidation and adiabatic-steam reforming which take place with one reactor.

• The process consists of a natural gas preheat section, a reactor and heat recovery section and a gas separation unit. A desulphurization unit is also present. The steam reforming of natural gas takes place in the autothermal reformer. A mixture of natural gas-steam and oxygen is fed to the reactor. Partial oxidation reactions occur in a combustion zone and then the products pass through a catalyst bed, where reforming reactions occur.

Production of Synthesis gas using partial oxidation of Natural gas:

Production of Synthesis gas using partial oxidation of Natural gas:

• The ATR reactor has a design similar to that of the POX reactor, but contains also a catalyst bed in the last part. The produced syngas temperature is about 1,300 K as compared to 1,650 K for the POX reactor.

• The advantages of (ATR):1. Synthetic gas of higher pressure can be obtained than by the steam

reforming method. 2. The large volumes of CO2 are produced. 3. The top of the combustion compartment reaches high temperatures

close to 2000ºC.

Production of Synthesis gas using partial oxidation of Natural gas:-

• The table show the Characteristics of syngas production methods

• Compound reforming method:• The compound reforming method combines the steam-reforming

reactor with the automatic-thermal reactor and the reaction take place in separate devices.

Production of Synthesis gas using partial oxidation of Natural gas:

• The advantage of Compound reforming method:– Low-pressure gas at the outlet of steam reforming reaction can be

transformed into high-pressure gas by means of automatic-thermal reforming.

– Costs are reduced because a compressor is not required.

• The disadvantages of Compound reforming method:– There are two reactors and construction costs are high.

Production of Synthesis gas using partial oxidation of Natural gas:

• Economy and Relative costs:• Comparison of economy by reforming method:

• Comparison of different process cost:

Production of Synthesis gas using partial oxidation of Natural gas:

• Feed stocks (Raw material):

• Natural gas (methane).

• Oxygen.

• Final products:

• Hydrogen.

• Carbon monoxide

Production of Synthesis gas using partial oxidation of

vacuum residue:

By a process called shell Gasification which include:

1. Gasification (Partial Oxidation)

2. Syngas Effluent Cooler (SEC)

3. Carbon Removal

Production of Synthesis gas using partial oxidation of

vacuum residue:

1. Gasification (Partial Oxidation):

It takes place in a refractory lined reactor that uses a specially designed burner

• The oxidant is preheated (to minimize oxygen consumption)

• Then mixed with steam before it is fed to the burner

• The oxidant and steam are intimately mixed with the preheated feed stock ( vacuum residue)

• feed stock is gasified in SGP reactor with oxygen to produce raw synthesis gas at a temperature of 1200 to 1500ºC and a pressure of 50 to 70 bar

Production of Synthesis gas using partial oxidation of

vacuum residue:

• Reactions:

CnHmSr +n/2 O2 nCO + (m/2 –r ) H2 + rH2S CO +1/2 O2 CO2 CO + H2O CO2 + H2 COS + H2 H2S +CO COS + H2O H2S +CO2 (CH2)n (CH4)n/2 +Cn/2 CH4 + H2O CO + 3H2 C + CO2 2CO C + H2O CO+H2

Production of Synthesis gas using partial oxidation of

vacuum residue:

2. Syngas Effluent Cooler (SEC)The hot reactor effuent gas is cooled to about 350°C. Saturated steam is produced at up to 120 bar. Some of it is used for preheating the oxygen and the feedstock.

3. Carbon RemovalThe soot particles and the ash are removed from the as in a two-stage water scrubber. This reduces the gas’s soot content to less than 1 mg/m3. The SGP process has been used successfully with two different technologies for separating soot from soot water.

Production of Synthesis gas using partial oxidation of

vacuum residue:Process Flowsheet:

Production of Synthesis gas using partial oxidation of

vacuum residue:

Safety•Allows relatively moderate process temperatures (1300 – 1350 °C).

•Very little soot formation

•Less fouling

Environmental ImpactNOx – 25 mg/Nm³ (dry – 15 % O2)SO2 – 10 mg/Nm³ (dry – 15 % O2)CO < 10 mg/Nm³ (dry – 15 % O2)Particulates < 1 mg/Nm³ (dry – 15 % O2)•The emissions are still low.

Economicsvacuum residuum which have the highest metal concentration, are the cheapest feedstock for gasification units.

Production of Synthesis gas using partial

oxidation of vacuum residue:

Feed stocks and Product:The final product stream contains syngas in which hydrogen to carbon

monoxide ratio is 2:1.

Feed stocks and Product:

Production of Synthesis gas using partial oxidation of

vacuum residue:Feed stocks (Raw material):

• vacuum residuum• oxygen• steam

Final products:• methane

• carbon dioxide• carbon monoxide

• hydrogen• nitrogen

•water

Uses of Syngas:

Ethanol production

* Ethanol was first prepared synthetically in 1826

*in 1920 ethanol was prepared by reacting syngas over catalysts.

The process

•First if the feed of syngas contain methane or CO2 its better to removed them to prevent the

accumulation and to increase the production of alcohol

*In the reactor the hydrogen and CO will react to produce ethanol,methanol and higher alcohol with methane.

* carbon monoxide will react with 2 hydrogen to produce methanol

* with 4 hydrogen to produce ethanol .

*with 3 hydrogen to produce methane.

CO+2H2 CH3OH2CO+4H2 C2H5OH+H2OCO + 3H2 CH4 +H2O

•For higher alcohol

nCO+2nH2 CnH(2n+1)OH+(n-1)H2O

•The water will react with CO to produce CO2.

•CO2+6H2 will produce ethanol

catalyst

Active metal combination which are CUO /alkali/AL2O3/Rh/ Zn.

Kineticshydrogen and carbon monoxide are converted using a Rhodium catalyst (the gray semicircle) into methanol (Step 3), methane (Step 6), ethanol (Step 9), and other oxygenates (Step 8

Process flowsheet

The process condition

*The best temperature range is 240 -350C and the pressure higher than 50 bar.

Properties of product:

•Alcohol are colorless liquid•They are toxic and flammable •Soluble in water •Methane is a colorless gas which has Solubility of 3.5mg/100ml

Enviromental impact:

the ethanol-blended fuels reduced CO2-equivalent greenhouse gas emissions by 7.8 million tons in 2005. ethanol is a cleaner-burning fuel than gasoline. At high concentrations, such as a result of leaks or spills, ethanol can have acute effects on a wide range of biota, where it may cause microbial death (ethanol is a disinfectant).

Ethanol uses :• As clean biofuel

• Ethanol fuel cell to produce electricity

• Feedstock for other organic compound

• Antibacterial and medical wipes

Thank you for

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