×

Producer Gas

Top
Download PDF
FAQ

What is Producer Gas?

Bookmark added to your notes.
View Notes
×

Producer gas is a mixture of gases that contain carbon monoxide gas, carbon dioxide gas, nitrogen gas, and hydrogen gas. From these gases, carbon monoxide gas and hydrogen gas are combustible gases. While carbon dioxide and nitrogen gases are non-combustible gases. 


Percentage Composition of Producer Gas 

The percentage composition of producer gas is discussed below:

Carbon dioxide = around 3%

Hydrogen gas = 10 % to 15 %

Carbon monoxide = 22 % to 30 %

Nitrogen gas = 50 % to 55 %

Non-combustible gases form the major portion of the producer gas. The large portion of non-combustible gas results in a high calorific value. The calorific value of the producer gas is around 1300 kCal/m³. 


Production of Producer Gas

[Image will be Uploaded Soon]

Parts of Producer Gas Formation Vessel:

  1. Preheated zone (the uppermost zone)

  2. Pyrolysis zone

  3. Reduction zone

  4. Oxidation zone

  5. Ash zone (the lowermost zone)- The ash generated from the producer gas formation is released out from this zone.  

  6. Inlet 

  7. Outlet 

Producer gas is formed in the cylindrical vessel. The diameter of this cylindrical vessel is around 3 m and the height is around 4 m. The coal and coke are added from the upper zone known as the pre-heated zone with the help of a cup and cone. The lowest zone of these vessels is known as the ash zone. The inlet is attached from this ash zone. This inlet carries the oxygen gas and steam gas to the upper zone (oxidation zone) also known as the combustion zone. The coal is heated in the presence of these oxygen gas and steam gas. In the oxidation zone, the carbon reacts with oxygen and forms the carbon dioxide and carbon monoxide gas as a product of combustion. The third zone is known as the reduction zone. In this reduction zone, the steam reacts with the carbon and produces carbon monoxide gas and hydrogen gas as a product of combustion. In the pyrolysis zone, the produced gas passed through this zone and heated at even higher temperature and released out from the outlet.


The Reaction Involved in the Formation of Producer Gas


Oxidation Reaction: This reaction takes place in the oxidation zone. This reaction is exothermic.

2 C + O₂ → CO₂

C + O₂ → 2CO


Reduction Reaction: This reaction occurs in the reduction zone. This reaction is endothermic.

C + H₂O → CO + H₂

CO₂ + C → 2 CO


Uses of Producer Gas

  • Producer gas is used as a fuel in various industries like iron manufacturing industries has been used for iron production.

  • Producer gas is used to remove the carbon dioxide gas from the fuel cells.

  • Producer gas is used to manufacture the fuel gas. On reacting the producer gas with the carbon dioxide it produces fuel gas.

  • Producer gas is used to produce hot air in the industries.

Generation of Biogas

Before discussing the generation of biogas, let’s first discuss what is biogas? Biogas is a mono carbon hydrocarbon (methane) rich fuel. The common name of biogas is gobar gas. The generation of biogas is done by the anaerobic breakdown or digestion of the biomass with the help of the methanogenic bacteria. 


Composition of the Biogas

Biogas is composed of methane gas, carbon dioxide, nitrogen gas, hydrogen sulphide, and hydrogen gas.

Methane gas = Around 50 % to 70 % 

Carbon dioxide = Around 30 % to 40 %

Hydrogen gas = In trace amount

Hydrogen sulphide gas = In trace amount

Nitrogen gas = In trace amount


Biogas Plant 

[Image will be Uploaded Soon]

Proteins, fats, cellulose, and hemicellulose undergo the microbial degradation process. These polymeric compounds get converted into soluble compounds or monomers. Now, these soluble compounds undergo the fermentation process. In this process, fermentative microbes convert these soluble compounds into organic acid. These organic acids now get attacked by the methanogenic bacteria and get converted into biogas (methane + carbon dioxide).


Flow Chart for the Biogas Production

Proteins, fats, cellulose, hemicellulose

↓ (in presence of decomposer microbes)

Soluble compounds or monomers

↓ (in presence of fermentative microbes)

Organic acid

↓ (in presence of methanogenic bacteria)

Biogas 


Methane is a naturally occurring gas that is increasing in concentration as a result of human activities. It is produced by bacterial fermentation under anaerobic conditions, such as swamps, marshes, rice paddies, landfills, and in the digestive tracts of the ruminants. It is also released during the production, transportation, and consumption of fossil fuels. Natural sources of methane, which include wetlands, termites, and oceans release on the order of 160 million tonnes of methane per year. Methane is removed from the atmosphere primarily by the reactions with the hydroxyl radical. Methane is one of the potent greenhouse gases. Therefore, it has a direct effect on radiative forcing. The destruction of methane produces an increased amount of ozone, which is itself a greenhouse gas.


Hydrogen Production

Let us discuss the hydrogen production method. There are two types of methods for hydrogen production. these methods are given below:

  1. Laboratory method for hydrogen production.

  2. Commercial method for hydrogen production.


Laboratory Methods

  • The Reaction of Acids with Metals- In this method acid reacts with the alkali or alkaline or transition metals earth metal and produces hydrogen gas as a product. 

Zn + 2 HCl → ZnCl2 + HCl

Only those metals can react with acid and produce hydrogen as a product, whose standard electrode potential value is negative. 

  • Reaction with Bases with the Metals- Some metals can react with the base and produce hydrogen gas as a by-product. 

Zn + 2 NaOH → Na2 Zn O2 + H2

2 Al + 2 KOH + 2 H2O → 2 K Al O2 + 3 H2


Commercial Method of Hydrogen Production 

There are various hydrogen production technologies involved in the commercial method of hydrogen production.

  • Hydrogen Production from Water (Electrolysis of Water)

In this method, two electrodes are present in the container. These two electrodes are connected with the external source of voltage with the help of the battery. The electrode connected with the negative terminal of the battery is known as the cathode. While the electrode connected with the positive terminal is known as an anode. The electrolysis of pure water is difficult to occur. A little amount of acid or base is added to the water solution. This addition results in making a good conductor of electricity. 

2 H2O + acid or base in trace amount → O2 + 2 H2


The Reaction at Different Electrodes

Anode Reaction:

2 OH⁻ → H2O + ½ O2 + 2e⁻

Cathode Reaction:

2 H2O + 2 e⁻ → H2 + 2OH⁻

Overall Reaction

H2O → H2 + ½ O2

[Image will be Uploaded Soon]

Electrolyzing the warm aqueous barium hydroxide solution between nickel electrodes leads to a high amount of pure hydrogen fuel production. 

  • Electrolysis of the Brine Solution- Hydrogen gas can be produced from the electrolysis of the brine solution. A high salt concentration solution is known as brine. The sodium chloride reacts with the water molecule and produces chlorine gas, hydrogen gas, and sodium hydroxide as a product. 

2 NaCl + 2 H2O → Cl2 + H2 + 2 NaOH

  • Steam and Hydrocarbon Reaction- This reaction occurs when the hydrocarbon or coke reacts with the steam at a very high temperature in the presence of a catalyst. 

C n H 2n + 2 + n H2O + Ni  → n CO + (2n + 1) H2


Natural Gas Production

Natural gas is a mixture of saturated hydrocarbons. Natural gas is composed of methane, ethane, propane, butane, carbon dioxide, hydrogen sulphide, and nitrogen gas. 


Percentage Composition of Natural Gas

Methane (CH4)- forms the 85 %portion of the natural gas

Ethane (C2H6)- It forms the 9 % portion of the natural gas

Propane (C3H8)- It forms the 3 % portion of natural gas.

Butane (C4H10)- It forms the 1 % portion of natural gas.

Carbon dioxide (CO2), hydrogen sulphide (H2S), nitrogen gas (N2)- These gas combined form the 2 %  portion of the natural gas.


Water Gas

The other name of water gas is syngas and synthesis gas. Some students get confused with the water gas and producer gas. You need to remember that water gas and producer gas are two different gases. Now let’s discuss the water gas in detail. Water-gas is a mixture of carbon monoxide gas, hydrogen gas, nitrogen gas, methane gas, carbon dioxide gas, and nitrogen gas. 


Composition of Water Gas

The major composition of water gas is formed by hydrogen gas and carbon monoxide gas. Rest gases like methane, nitrogen, and carbon dioxide form the minor components of water gas.

Hydrogen - Forms around 50 % part of the water gas.

Carbon monoxide (CO) - Forms around 45 % part of the water gas.

Methane (CH4), carbon dioxide (CO2), and nitrogen (N2) - forms the 5 % part of the water gas. 


Preparation of the Water Gas

Water-gas can be prepared by reacting the coke or hydrocarbon with the steam of water. Carbon monoxide and hydrogen gas are formed in this reaction. The mixture of this gas is known as water gas or syngas.

C + H2O → CO + H2

The calorific value of the gas can be determined by the help of the gas composition of the particular gas. 


Did You Know?

  • The calorific value of the coal gas is the highest and the calorific value of producer gas is the lowest.

  • Do you know that pure water is a bad conductor of electricity? The electrolysis of pure water is possible in the presence of a very high electric field and keeping the distance between the electrode to a very low distance (around 100 nm).

  • The United States and Russia are the largest natural gas producers. 

FAQ (Frequently Asked Questions)

Question: What is the Composition of Water Gas?

Answer: The composition of water gas is discussed below:

Hydrogen gas and carbon monoxide gas forms the major component of water gas. There are other more gases that are present in the water-gas but in a minor portion. These minor gases are methane, nitrogen, and carbon dioxide. These trace gases play an important role in maintaining the function of these gases.

Hydrogen gas (H₂)- makes 50 % of the water gas.

Carbon monoxide gas (CO) -makes 45 % portion of the water gas.

Methane gas (CH₄), carbon dioxide gas (CO₂), and nitrogen gas (N₂) - Makes 5 % portion of the water gas. 

Question: Discuss the Various Methods for Hydrogen Gas Production.

Answer: The various method for hydrogen gas production are discussed below:

  • Hydrogen Production from Water (Electrolysis of Water) 

Two electrodes are dipped in the aqueous solution. These two different electrodes are interconnected with the external source of the current with the help of the battery. In this connection, the electrode that is connected with the negative terminal of the battery is known as a cathode electrode. While the electrode attached to the positive terminal of the battery is known as an anode. The electrolysis of pure water is difficult to occur. A little amount of strong electrolytes like acid or base is added to the water medium. This addition results in making a good conductor of electricity. 

2 H₂O + acid or base in trace amount → O₂ + 2 H₂

The reaction occurring at different electrodes

Anode reaction:

2 OH⁻ → H₂O + ½ O₂ + 2e⁻

Cathode reaction:

2 H₂O + 2 e⁻ → H₂ + 2OH⁻

Overall reaction

H₂O → H₂ + ½ O₂

The electrolyzing process can be enhanced by the addition of warm aqueous barium hydroxide solution between the nickel electrodes. It leads to a high amount of pure hydrogen fuel production. 

  • Electrolysis of the Brine Solution

Dihydrogen gas can be obtained from the electrolysis of the brine solution. The solution with a high salt concentration is known as a brine solution. The sodium chloride salt reacts with the water molecule to produce chlorine gas, hydrogen gas, and sodium hydroxide as a product of the reaction. 

2 NaCl + 2 H₂O → Cl₂ + H₂ + 2 NaOH

  • Steam and Hydrocarbon Reaction

This reaction takes place when the hydrocarbon or coke combines with the water steam at a very high temperature and in the presence of a catalyst. 

CₙH₂ₙ ₊ ₂ + n H₂O + Ni  → n CO + (2n + 1) H₂