Pembakaran: Perbezaan antara semakan

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'''Pembakaran''' adalah satu is a proses kimia, satu [[tindakbalas eksotermik]] di antara satu bahan ([[bahan api]]) dan satu gas ([[pengoksidan]]), biasanya O<sub>2</sub>, untuk membebaskan [[haba]]. Dalam satu tindakbalas pembakaran yang sempurna, satu sebatian akan bertindakbalas dengan satu unsur yang beroksigen, dan hasilnya adalah sebatian dari setiap unsur bergabung di dalam bahanapi dengan unsur yang beroksigen. Sbagai contoh:
[[ImageFail:Forestfire2.jpg|thumb|right|300px|Pembakaran hutan.]]
[[ImageFail:Gas burner on stove.JPG|thumb|right|225px|Pembakaran gas di dapur.]]
[[metana|CH<sub>4</sub>]] + 2 [[oksigen|O<sub>2</sub>]] &rarr; [[karbon dioksida|CO<sub>2</sub>]] + 2 [[air|H<sub>2</sub>O]] + [[haba]]
 
[[metil sulfida|CH<sub>2</sub>S]] + 6 [[fluorin|F<sub>2</sub>]] &rarr; [[karbon tetrafluorida|CF<sub>4</sub>]] + 2 [[hidrogen fluorida|HF]] + [[sulfur heksafluorida|SF<sub>6</sub>]] + haba<br /><br />
 
== Jenis Pembakaran ==
Terdapat beberapa jenis pembakaran: -
 
=== Pembakaran Marak/Cepat ===
Pembakaran Marak/Cepat adalah merupakan satu bentuk pembakaran yang mana banyak tenaga haba dan cahaya dibebaskan. Pembakaran sebegini biasanya wujud sebagai [[Api|api]].
Biasanya pembakaran ini digunakan dalam bentuk mekanisme, seperti [[enjin pembakaran dalaman]], dan dalam [[senjata termobarik]].
{{terjemah}}
 
=== Pembakaran Perlahan ===
Pembakaran perlahan adalah satu bentuk pembakaran yang berlaku pada suhu rendah. [[Respirasi sel|Respirasi]] adalah satu contoh pembakaran perlahan.
 
=== Pembakaran Sempurna ===
Dalam pembakaran lengkap, zat tindakbalas akan terbakar di dalam oksigen, menghasilkan beberapa jenis produk. Apabila [[hidrokarbon]] terbakar di dalam oksigen, kesan tindakbalas akan hanya menghasilkan karbon dioksida dan air. Apabila elemen seperti karbon, nitrogen, sulfur dan besi terbakar, elemen tersebut akan menghasilkan oksida yang paling umum. Karbon akan menghasilkan karbon dioksida. Nitrogen akan menghasilkan [[nitrogen dioksida]]. Sulfur akan menghasilkan [[sulfur dioksida]]. Besi akan menghasilkan [[besi(III) dioksida]]. Pembakaran lengkap pada amnya adalah mustahil untuk dicapai kecuali tindakbalas yang berlaku dikawal secara berhati-hati (e.g. di dalam persekitaran makmal).
 
=== Pembakaran Turbulasi ===
 
Turbulent combustion is a combustion characterized by turbulent flows. It is the most used for industrial application (e.g. gas turbines, diesel engines, etc.) because the turbulence helps the mixing process between the fuel and oxidizer.
 
=== Pembakaran Tidak Sempurna ===
In incomplete combustion there is an inadequate supply of oxygen for the combustion to occur completely. The reactant will burn in oxygen, but will produce numerous products. When a hydrocarbon burns in oxygen, the reaction will yield carbon dioxide, water, carbon monoxide, and various other compounds such as nitrogen oxides. Incomplete combustion is much more common and will produce large amounts of byproducts, and in the case of burning fuel in automobiles, these byproducts can be quite lethal and damaging to the environment.
 
=== Pembakaran Pendam ===
[[Smoulder|Smouldering combustion]] is a flameless form of combustion, deriving its heat from heterogeneous reactions occurring on the surface of a solid fuel when heated in an oxidizing environment. The fundamental difference between smouldering and flaming combustion is that in smouldering, the oxidation of the reactant species occurs on the surface of the solid rather than in the gas phase. The characteristic temperature and heat released during smouldering are low compared to those in the flaming combustion of a solid. Typical values in smouldering are around 600 &nbsp;°C for the peak temperature and 5 kJ/g-O2 for the heat released; typical values during flaming are around 1500 &nbsp;°C and 13 kJ/g-O2 respectively. These characteristics make smolder to propagate at low velocities, typically around 0.1 mm/s, which is about two orders of magnitude lower than the velocity of flame spread over a solid. In spite of its weak-combustion characteristics, smouldering is a significant fire hazard.
 
== Persamaan Kimia ==
Secara umumnya, [[persamaan kimia]] untuk pembakaran sempurna [[hidrokarbon]] (contohnya[[oktana]]) dalam [[oksigen]] adalah seperti berikut:
:C<sub>''x''</sub>H<sub>''y''</sub> + (''x'' + ''y''/4)O<sub>2</sub> &rarr; ''x''CO<sub>2</sub> + (''y''/2)H<sub>2</sub>O
Contoh pembakaran [[propana]] adalah:
:C<sub>3</sub>H<sub>8</sub> + 5O<sub>2</sub> &rarr; 3CO<sub>2</sub> + 4H<sub>2</sub>O
 
Persamaan kimia mudah bagi pembakaran [[hidrokarbon]] adalah:
:[[bahan pembakaran]] + [[Oksigen]] &rarr; [[haba]] + [[air]] + [[karbon dioxida]].
 
== Pembakaran bahan api cecair ==
Pembakaran bahan api cecair dalam atmosfera pengoksidaan sebenarnya berlaku di dalam fasa gas, iaitu wap yang terbakar bukannya cecair. Oleh itu, cecair biasanya akan menyala hanya di atas satu suhu tertentu yang dikenali sebagai [[takat kilat]]. Sekiranya suhu cecair berada di bawah suhu ini, ia tidak akan menyejat dengan cukup pantas untuk membentuk wap yang akan akan menyokong proses pembakaran.
 
== Pembakaran Bahanapi Pepejal ==
The act of combustion consists of three relatively distinct but overlapping phases:
* '''Preheating phase''', when the unburned [[fuel]] is heated up to its flash point and then [[fire point]]. Flammable gases start being evolved in a process similar to [[dry distillation]].
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* '''Charcoal phase''' or '''solid phase''', when the output of flammable gases from the material is too low for persistent presence of flame and the [[charring|charred]] fuel does not burn rapidly anymore but just glows and later only [[smouldering|smoulders]].
 
== Suhu Pembakaran ==
Assuming perfect combustion conditions, such as an [[adiabatic]] (no heat loss) and complete combustion, the adiabatic combustion temperature can be determined. The formula that yields this temperature is based on the [[first law of thermodynamics]] and takes note of the fact that the [[heat of combustion ]] (calculated from the fuel's [[heating value]]) is used entirely for warming up fuel and gas (e.g. oxygen or air).
 
In the case of fossil fuels burnt in air, the combustion temperature depends on
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The adiabatic combustion temperature increases for higher heating values and inlet temperatures and stoiciometric ratios towards one.
 
Typically, the adiabatic combustion temperatures for coals are around 1500 &nbsp;°C (for inlet temperatures of room temperatures and <math>{\lambda = 1.0}</math>), around 2000 &nbsp;°C for oil and 2200 &nbsp;°C for natural gas.
 
== Analisis Pembakaran ==
Combustion analysis is a process used to determine the composition of organic compounds.
 
== Pautan Luar ==
*[http://www25.brinkster.com/denshade/hydro.html Hydrocarbon combustion] Simple applet that illustrates the Chemical equation.
*[http://www.normanchigier.com/Fuel_Injection_email.html Fuel efficiency (stoichiometric air fuel mixture) vs. decreased emissions in combustion engines]
 
== Lihat Juga ==
* [[Karbon dioksida]]
* [[Deflagration]]
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** [[Immolation]]
 
[[CategoryKategori:Pembakaran| ]]
[[CategoryKategori:Proses Kimia]]
 
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