production of biogas

the composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55%–75% methane,^[10] which for reactors with free liquids can be increased to 80%-90% methane using in-situ gas purification techniques.^[11] As produced, biogas contains water vapor. The fractional volume of water vapor is a function of biogas temperature; correction of measured gas volume for water vapor content and thermal expansion is easily done via simple mathematics which yeilds the standardized volume of dry biogas

Typical composition of biogas

Compound	Formula	%
Methane	CH 4	50–75
Carbon dioxide	CO 2	25–50
Nitrogen	N 2	0–10
Hydrogen	H 2	0–1
Hydrogen sulphide	H 2S	0–3
Oxygen	O 2	0–0

biogas

Biogas typically refers to a mixture of different gases produced by the breakdown of many organic matter in the absence of some oxygen. Biogas can be produced from regionally available raw materials such as recycled waste. It is a renewable energy source and in many cases exerts a very small carbon footprint.

Biogas is produced by anaerobic digestion with anaerobic bacteria or fermentation of biodegradable materials such as manure,sewage, municipal waste, green waste, plant material, and crops.^[1] It is primarily methane (CH
4) and carbon dioxide (CO
2) and may have small amounts of hydrogen sulphide (H
2S), moisture and siloxanes.

The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.^[2]

Biogas can be compressed, the same way natural gas is compressed to CNG, and used to power motor vehicles. In the UK, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel.^[3] It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards when it becomes bio methane.

methane

Methane  is a chemical compound with the chemical formula CH
4 (one atom of carbon and four atoms of hydrogen). It is the simplest alkane and the main component of natural gas. The relative abundance of methane makes it an attractive fuel, though capturing and storing it poses challenges due to its gaseous state found at normal conditions. In its natural state, methane is found both below ground, and under the sea floor, where it often finds its way to the surface and in the earth's atmosphere where it is known as atmospheric methane.

ignition temperature of different fuels

Fuel or Chemical	Autoignition Temperature
	(oC)	(oF)
Acetaldehyde	175	347
Acetic acid	427	801
Acetone, propanone	465	869
Acetylene	305	581
Anthracite - glow point	600	1112
Benzene	560	1040
Bituminous coal - glow point	454	850
Butane	405	761
Butyl acetate	421	790
Butyl alcohol	345	653
Butyl methyl ketone	423	793
Carbon	700	1292
Carbon disulfide, CS2	90	194
Carbon monoxide	609	1128
Charcoal	349	660
Coal-tar oil	580	1076
Coke	700	1292
Cyclohexane	245	473
Cyclohexanol	300	572
Cyclohexanone	420	788
Dichloromethane	600	1112
Diethylamine	312	594
Diethylether	160	320
Diethanolamine	662	1224
Diesel, Jet A-1	210	410
Diisobutyl ketone	396	745
Diisopropyl ether	443	829
Dimethyl sulphoxide	215	419
Dodecane, dihexyl	203	397
Epichlorohydrin	416	781
Ethane	515	959
Ethylene. ethene	490	914
Ethyl acetate	410	770
Ethyl Alcohol, Ethanol	365	689
Fuel Oil No.1	210	410
Fuel Oil No.2	256	494
Fuel Oil No.4	262	505
Furfural	316	601
Heavy hydrocarbons	750	1382
Heptane	204	399
Hexane	223	433
Hexadecane, cetane	202	396
Hydrogen	500	932
Gas oil	336	637
Gasoline, Petrol	246 - 280	475 - 536
Glycerol	370	698
Gun Cotton	221	430
Kerosene	295	563
Isobutane	462	864
Isobutene	465	869
Isobutyl alcohol	426	799
Isooctane	447	837
Isopentane	420	788
Isopropyl alcohol	399	750
Isophorone	460	860
Isohexane	264	507
Isononane	227	440
Isopropyl Alcohol	399	750
Light gas	600	1112
Light hydrocarbons	650	1202
Lignite - glow point	526	979
Magnesium	473	883
Methane (Natural Gas)	580	1076
Methanol, Methyl Alcohol	470	878
Methyl acetate	455	851
Methyl ethyl ketone	516	961
Naphtha	225	437
Neoheaxane	425	797
Neopentane	450	842
Nitrobenzene	482
Nitro-glycerine	254	490
n-Butane	405	761
n-Heptane	215	419
n-Hexane	225	437
n-Octane	220	428
n-Pentane	260	500
n-Pentene	298	569
Oak Wood - dry	482	900
Paper	218 - 246	424 - 475
Peat	227	440
Petroleum	400	752
Pine Wood - dry	427	800
Phosphorus, amorphous	260	500
Phosphorus, transparent	49	120
Phosphorus, white	34	93
Production gas	750	1382
Propane	470	878
Propyl acetate	450	842
Propylene, propene	458	856
Pyridine	482	900
p-Xylene	530	986
Rifle Powder	288	550
Triethylborane	-20	-4
Toluene	535	995
Semi anthracite coal	400	752
Semi bituminous coal - glow point	527	980
Silane	< 21	< 70
Styrene	490	914
Sulphur	243	470
Tetrahydrofuran	321	610
Toluene	530	986
Trichloroethylene	420	788
Wood	300	572
Xylene	463	867

another methods to conserve fossil fuels using solar energy.

Solar energy is radiant light and heat from the sun harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaics, solar thermal energy, solar architecture and artificial photosynthesis.

It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on the way they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating global warming, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared".

how does candle burn ( must watch video)

https://www.youtube.com/watch?v=52d8hasNrJc

Calorific values of solid, liquid and gaseous fuels

Solid and liquid fuels	Gross calorific value/ MJ kg−1
AlcoholsEthanol	30
Methanol	23
Coal and coal productsAnthracite (4% water)	36
Coal tar fuels	36–41
General purpose coal (5–10% water)	32–42
High-volatile coking coals (4% water)	35
Low temperature coke (15% water)	26
Medium-volatile coking coal (1% water)	37
Steam coal (1% water)	36
Peat Peat (20% water)	16
Petroleum and petroleum productsDiesel fuel	46
Gas oil	46
Heavy fuel oil	43
Kerosine	47
Light distillate	48
Light fuel oil	44
Medium fuel oil	43
Petrol	44.8–46.9
WoodWood (15% water)	16

Gaseous fuels at 15 °C, 101.325 kPa, dry	Gross calorific value/MJ m− 3
Coal gas coke oven (debenzolized)	20
Coal gas continuous vertical retort (steaming)	18
Coal gas low temperature	34
Commercial butane	118
Commercial propane	94
North Sea gas natural	39
Producer gas coal	6
Producer gas coke	5
Water gas carburetted	19
Water gas blue	11