22
edits
Difference between revisions of "Gasification"
Jump to navigation
Jump to search
m
Proofreading- some little adjustments
(→Drying) |
Aylin Özgen (talk | contribs) m (Proofreading- some little adjustments) |
||
| Line 6: | Line 6: | ||
}} | }} | ||
<onlyinclude>'''Gasification''' is the conversion of a solid or liquid organic compound in a gas phase and a solid phase. The gas phase, usually called 'syngas' or 'producer gas', has a high heating power and can be used for power generation or biofuel production. The solid phase, called char, includes the organic unconverted fraction and the inert material present in the treated feedstock.</onlyinclude> The syngas produced is a gas mixture of carbon monoxide (CO), hydrogen (H<sub>2</sub>), methane (CH<sub>4</sub>) and carbon dioxide (CO<sub>2</sub>) as well as light hydrocarbons, such as ethane and propane, and heavier hydrocarbons, such as tars. Undesirable gases, such as sulphidric (H<sub>2</sub>S) and chloridric acid (HCl), or inert gases, such as nitrogen (N<sub>2</sub>), can be present in the syngas. Conversion of organic material is achieved by exposing the feedstock to high temperatures, typically 700°C - 1100°C in the presence of a gasifying agent. The gasifying agents used are air, oxygen, steam or a mixture thereof. | <onlyinclude>'''Gasification''' is the conversion of a solid or liquid organic compound in a gas phase and a solid phase. The gas phase, usually called 'syngas' or 'producer gas', has a high heating power and can be used for power generation or biofuel production. The solid phase, called char, includes the organic unconverted fraction and the inert material present in the treated feedstock.</onlyinclude> The syngas produced is a gas mixture of carbon monoxide (CO), hydrogen (H<sub>2</sub>), methane (CH<sub>4</sub>), and carbon dioxide (CO<sub>2</sub>), as well as light hydrocarbons, such as ethane and propane, and heavier hydrocarbons, such as tars. Undesirable gases, such as sulphidric (H<sub>2</sub>S) and chloridric acid (HCl), or inert gases, such as nitrogen (N<sub>2</sub>), can be present in the syngas. Conversion of organic material is achieved by exposing the feedstock to high temperatures, typically 700°C - 1100°C in the presence of a gasifying agent. The gasifying agents used are air, oxygen, steam or a mixture thereof. | ||
Gasification of organic material offers several advantages. The produced syngas can be more efficient than direct combustion of the original feedstock, and can be used for multiple applications, such as heat and electricity generation, including high temperature heat for industry, for mechanical energy, as transport fuel, as raw material for chemicals, and when cleaned and upgraded to near pure methane, can be injected into the grid. | Gasification of organic material offers several advantages. The produced syngas can be more efficient than direct combustion of the original feedstock, and can be used for multiple applications, such as heat and electricity generation, including high temperature heat for industry, for mechanical energy, as transport fuel, as raw material for chemicals, and when cleaned and upgraded to near pure methane, can be injected into the grid. | ||
| Line 39: | Line 39: | ||
<chem>H2 + 1/2O2 -> H2O</chem> ΔH = -242 kJ/mol (Hydrogen combustion) | <chem>H2 + 1/2O2 -> H2O</chem> ΔH = -242 kJ/mol (Hydrogen combustion) | ||
The main product of this phase is | The main product of this phase is thermal energy, while the combustion product is a gas mixture of CO, CO<sub>2</sub> and water. | ||
==== Drying ==== | ==== Drying ==== | ||
| Line 49: | Line 49: | ||
<chem>Biomass <=> H2 + CO + CO2 + CH4 + H2O + Tar + Char</chem> | <chem>Biomass <=> H2 + CO + CO2 + CH4 + H2O + Tar + Char</chem> | ||
Since the feedstock is made of biomass and cellulose is its main component, in this reaction the biomass can be indicated with the chemical formula of cellulose (i.e., C<sub>6</sub>H<sub>10</sub>O<sub>6</sub>) | |||
==== Reduction ==== | ==== Reduction ==== | ||
The reduction step involves the reaction between the products of the preceding stages of pyrolysis and oxidation, which results in the formation of the final syngas. The main reactions occurring | The reduction step involves the reaction between the products of the preceding stages of pyrolysis and oxidation, which results in the formation of the final syngas. The main reactions occurring during the reduction step are as follows: | ||
<chem>C + CO2 +<-> 2 CO</chem> (Boudouard reaction) | <chem>C + CO2 +<-> 2 CO</chem> (Boudouard reaction) | ||