What is Coal: Definition and 70 Discussions

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands—called coal forests—that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times. However, many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras.
Coal is primarily used as a fuel. While coal has been known and used for thousands of years, its usage was limited prior to the Industrial Revolution. With the invention of the steam engine coal consumption increased. As of 2016, coal remains an important fuel as it supplied about a quarter of the world's primary energy and two-fifths of electricity. Some iron and steel making and other industrial processes burn coal.
The extraction and use of coal causes many premature deaths and much illness. The coal industry damages the environment, including by climate change as it is the largest anthropogenic source of carbon dioxide, 14.4 gigatonnes (Gt) in 2018, which is 40% of the total fossil fuel emissions and over 25% of total global greenhouse gas emissions. As part of the worldwide energy transition many countries have reduced or eliminated their use of coal power, and the UN Secretary General has asked governments to stop building new coal plants by 2020. Coal use peaked in 2013 but to meet the Paris Agreement target of keeping global warming to well below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030.The largest consumer and importer of coal is China. China mines almost half the world's coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports, followed by Indonesia and Russia.

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  1. hagopbul

    Questions about energy generation from coal

    Hello : i was watching the news , and it was all about how Europe will start the coal factories again for energy generation had a question related to reduction of coal consumption for energy generation 1 ) could we use coal fine particles instead of chunks of coal that will burn more...
  2. maajdl

    Your thoughts about the entropy of coal?

    In the industry, coal and other fuels are typically represented by - their C, H, O, N, S elemental composition for the combustible part - the composition of the ashes (SiO2, Al2O3, Fe2O3, ...) - the Low Heat Value (LHV) which is the heat that can be extracted from combustion product With...
  3. BWV

    Can Coal Deposits Explain the Fermi Paradox?

    Reading McGhee's excellent book on the Carboniferous period and he explains in detail the unique circumstances behind the creation of 90% of the world's coal deposits - receding ocean in an ice age that created low lying swamps, high concentrations of oxygen in the atmosphere that would have...
  4. mfb

    B Coal and total CO2 emissions in the UK

    Mentor note: This thread started as side-discussion in the thread New Tokamak D Mode Success - Fusion is Almost Here, see there for earlier posts that lead to this discussion. I split the threads. Everything from post 2 to post 20 was moved, later posts were made here.
  5. I

    Coal vs Oil Formation: What's the Difference?

    So I'm learning in a class that coal is made when land plants (in swamps) die and then get buried in sediments, and with the Earth's pressure/temperature the plants become coal. Then I learned that when ocean plants (like algae and plankton) die, they also get buried in sediments in the sea...
  6. Auto-Didact

    News Scientists turn CO2 back into coal

    Climate rewind: Scientists turn carbon dioxide back into coal The article says that this process takes place using a liquid metal catalyst at room temperature and is both efficient and scalable. The rest of the article can be read over at phys.org (link in title). The published paper (open...
  7. A

    Higher and Lower heat value of combustion of Coal?

    hello my friends , i have two question about calorific value of coal why Lower heating value decrease with increase oxygen content but increase with increasing hydrogen , sulfur and carbon content ? Do this elements influence the higher heating value or not ?
  8. B

    Exploring Vertical Retorts for Coal Distillation Processes

    This is regarding vertical retorts, specifically those used in "distillation" of coal to produce coal (town) gas, tar and other by products. It is understood that the distillation of coal is done by heating coal in an air (oxygen) free container (ie in a retort). The vertical retort is...
  9. E

    A train dragging coal while more coal is added into it....

    Homework Statement A locomotive is dragging empty freight cars, while coal is being dropped into them. It’s falling down into those freight cars with an efficiency (μ). Overall mass of the whole empty train is M. a) Calculate v(t) (velocity with respect to time), assuming that the force of...
  10. wolram

    Efforts to revive coal industry unlikely to work

    https://www.sciencedaily.com/releases/2017/10/171027085523.htmCurrent federal efforts to revive the coal industry will likely do more harm than good to fragile Appalachian communities transitioning from coal as a major source of employment, according to a new study. What do you think...
  11. K

    (thermo) how to calculate the temperature of a coal furnace (applied)

    I am an new EE with my FE, but my thermo knowledge is lacking in many areas. Its one area where i would like to become an expert. So i try to find ways of applying thermo analysis on my free time to imprve my skills. where here is one and I have no idea where to even start. a youtuber with a...
  12. agargento

    Electrical Energy: 30-Day Output from Coal Plant

    Homework Statement A power plant burns coal and generates an average of 700.0 Megawatts (MW) of electrical power while discharging 1162.00 MW as waste heat. Find the total electrical energy generated by the plant in a 30-day period. Homework Equations W = J/sec The Attempt at a Solution...
  13. J

    Coal Exhaust Making a Solar Updraft Tower Work

    I was thinking of ways of making carbon cleaner for the environment. One of the ways I came up with is filling a solar updraft tower https://en.wikipedia.org/wiki/Solar_updraft_tower with the exhaust from a gas/coal plant. So you'd get a true greenhouse gas accumulation of heat going in the...
  14. R

    Coal Gasifier - Thermodynamics Question

    Homework Statement The problem is in the attached picture. I simply do not know what an "equilibrium equation" is and what it means by the composition. My professor is unbelievably difficult to get a straight, understandable answer from. I've already taken thermodynamics, but we did not learn...
  15. R

    Combustion of Coal in a boiler

    A quantity of coal used in a boiler had the following analysis: 82% C; 5% H; 6% O; 2% N; 5% ash. The dry flue gas analysis showed 14% CO2 and some oxygen. Calculate the oxygen content of the dry flue gas. I have first written the formula for combustion including the variables for balancing the...
  16. C

    Lower and Higher Heating Values of Coal: Why do they exist?

    Hello friends, The balanced chemical equation for the combustion of carbon is: C(solid) + O2(gas) -> CO2(gas) Now, the lower and higher heating value of hydrocarbon fuels (such as methane) exists because in the LOWER heating value, you are subtracting away the latent heat of vaporization of...
  17. Jonski

    Energy Intensity of black coal

    Homework Statement Brown coal, energy content 16 MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant. Homework Equations What is the emissions intensity (kg CO2 emitted/kWh delivered) ? Compare this to Hazelwood which is 1.53 tCO2/Mwh 3. The Attempt at a Solution...
  18. N

    Simulation of dual porosity in coal using COMSOL Multiphysic

    Hi, I would kindly appreciate it if someone could help me with my simulation problem. I am trying to simulate dual porosity in coal and the interaction of coal matrix and fracture flow. The problem I'm having is I can't assign separate domains with different pressures for matrix and fracture in...
  19. D

    Fossil Fuels vs. Natural Gas: Carbon Emissions Explained

    Hi there, Could someone explain to me why fossil fuels, such as coal and oil, produce fewer particulate matter emissions than natural gas? Also, how would you expect the combustion temperature of these fuels to affect particulate emissions? Would a higher temperature lead to a more complete...
  20. A

    Coal Dust Contamination: Environmental Concerns and Impact on Waterways

    First I'm hoping this is in the right section. There is a big debate in the high plains of the Rockies and the Pacific Northwest about coal being transported by rail in open top hopper cars. The debate seems to center on coal dust and bits of coal making its way into the water ways. As far as...
  21. P

    Why doesn't coal have a flame?

    Wood burns with flame but coal does not. Why?
  22. L

    How to light Coal with matches only

    Hi everyone ,, Am doing a project and I want to light coal with matches only ,, I have 2 Ideas only , mix coal with sulfur or mix it with petroleum fuel .. I want to know will it light using any of those methods ?? with only matches ? Is it safe ? and will there be any smell out of it ...
  23. S

    What significance does brownian motion has to do with coal explosion?

    Apparently : What significance does brownian motion has to do with coal explosion?[Brownian motion or pedesis is the presumably random moving of particles suspended in a fluid (a liquid or a gas) resulting from their bombardment by the fast-moving atoms or molecules in the gas or liquid.] Now...
  24. russ_watters

    Revolutionary Process Reduces Coal Pollution by 99%

    http://www.foxnews.com/science/2013/02/20/coal-cleanest-energy-source-there-is/?intcmp=HPBucket#ixzz2LUZ8Z69v I'm not seeing it. The problem is obvious: The primary combustion products of coal are water and carbon dioxide. The proportions vary with the type of coal, but a considerable...
  25. J

    Avtomatisation of industrial coal burning boiler

    Homework Statement Image: http://www.coal2nuclear.com/Fossil%20Fuel%20Power%20Station%20Core%20-%20Relabeled%20-%20982.jpg I need to know the critical parameters of getting steam, so that i know which measuring instruments to use and where to put them so that following statemnts are true...
  26. S

    Power output of a coal burning power plant

    Homework Statement A coal power plant with 30% efficiency burns 10 kilograms of coal per day. (Take the heat of combustion of coal to be 30 MJ/kg) a) what is the power output of the plant? b) At what rate is thermal energy being discarded by this plant? c) If the thermal energy is carried...
  27. D

    Calculating coal CO2 emission intensity (kg CO2 emitted/kWh delivered)

    Hi all, Would really appreciate some help on this problem I can't seem to figure out. Brown coal has an energy content of 15MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant. Calculate the CO2 emission intensity (kg CO2 emitted/kWh delivered).Assume complete...
  28. W

    MHB Solving a Coal Blending Problem with LP

    Can someone explain what is being asked in this problem. I find it quite confusing. Particularly equation [3]. Thank you. ................ A firm selling cooking coal to power stations, requires to formulate a blend of coal with a phosphorus content of at most 0.04% and ash impurity of at...
  29. X

    Would a Falling Hot Coal Still Burn Someone on the Ground?

    So a sadistic friend of mine posed this question: Of course this question can be thought of in two ways: a) would the surface still be hot enough at the bottom or b) would the interior be hot enough at the bottom (since the coals would probably break, its a relevant question). At the time...
  30. I

    Entropy of the river due to coal heating

    Gamma (Cp/Cv) of a gas Homework Statement An experimenter adds 980 J of heat to 1.75 mols of an ideal gas to heat it from 10.0 C to 25.0 C at constant pressure. The gas does 234 J of work during the expansion. Calculate gamma (Cp/Cv) for the gas. Homework Equations Cv=Cp-nR Gamma...
  31. N

    Coal needed to produce 100000 BTU/s

    how much coal is required to produce 100000 BTU/s in a typical house? I have been looking and looking with no leads on it need help please
  32. jtbell

    Chopsticks to China = coal to Newcastle?

    You be the judge... Georgia's hottest export: Chopsticks!
  33. J

    Is Nuclear Power More Efficient Than Coal in Energy Production?

    Hello, I'm wondering if the brains here can help me point to some good sources for some particular information I'm looking for, and perhaps help me figure out the correct math for some problems I'm interested in solving. I've seen a statement that, in general, ball-park figures...
  34. R

    Coal Ash Is More Radioactive than Nuclear Waste?

    Is this true? How do you refute it? http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste
  35. W

    Help Needed: Producing Durable Coal Briquettes Under Rain

    Hi all, I hope to get some help from you here. I'm a quality engineer working for a coal briquettes company in Turkey. What we do is collecting the coaldust from all over Turkey and make them briquettes by pressing under high pressure (70-80 bars). We add some extra binder materials to the...
  36. Y

    Designing coal feeders for a powerplant.

    I was given this problem as an excercise in thermodynamics and to better understand powerplant systems. I am having difficulties because as a civil engineering student I haven't taken a lot of thermodynamics. The one course I did take was several semesters ago and wasn't that advanced...
  37. P

    How Does Releasing Coal Affect the Speed and Dynamics of a Railroad Car?

    Homework Statement A railroad hopper car has a mass of 20000 kg when empty and contains 30000 kg of coal. As it coasts along the track at 7 m/s the hopper opens and steadily releases all the coal onto a platform below the rails over a period of 5 s. a) How fast does the car travel after all...
  38. B

    Can an Accounting Major Make Coal?

    I'm new here and I'm in no way a Science person or a Eco person. The fact is that I'm an Accounting major with an idea. Would it be possible to take CO2, remove the oxygen and concentrate the Carbon into coal? I got this idea while watching part of a "green" show. They were showing how...
  39. B

    Momentum - Throwing coal out of railroad car

    Homework Statement A railroad hopper car has a mass of 50000 kg when empty and contains 30000 kg of coal. As it coasts along the track at 8 m/s the hopper opens and steadily releases all the coal onto a platform below the rails over a period of 4 s. How fast does the car travel after all...
  40. J

    Comparative GHG Emissions of Coal, Domestic Natural Gas, LNG, and SNG

    You might be interested in this paper: Jaramillo, P., W. M. Griffin, and H.S. Matthews. 2007. Comparative life-cycle air emissions of coal, domestic natural gas, LNG, and SNG for electricity generation. Environmental Science & Technology, Vol. 41, No. 17, 6290-6296 You can download it here...
  41. C

    A: "Transforming Coal into Diamond: How Much Does One Pound of Gold Compress?"

    If I have one pound of gold heated and compressed into a diamond, what will the weight of the diamond be? PS
  42. Spinnor

    Where on Earth are possible coal and oil of tomorrow forming today?

    Where on Earth are possible coal and oil of "tomorrow" forming today? Where on Earth are possible coal and oil of tomorrow, as in many many years from now, forming today? Thanks for your help!
  43. T

    Coal Car and horizontal impulse

    Homework Statement A railroad hopper car has a mass of 30000 kg when empty and contains 50000 kg of coal. As it coasts along the track at 5 m/s the hopper opens and steadily releases all the coal onto a platform below the rails over a period of 4 s. What is the horizontal impulse delivered to...
  44. S

    If diamonds are made of carbon? and coal is made out carbon

    If diamonds are made of carbon? and coal is made out carbon, why are diamonds transparent and coal is not transparent?
  45. T

    What are Some Calculus-Based Project Ideas for a High School Coal Fair?

    I don't think this counts as a homework question and if it does, I'm sorry. At my high school, we have an annual coal fair and I wanted to do a calculus-based math project, but I'm having trouble coming up with any good ideas. The project can be about any part of the coal industry, so does...
  46. M

    Only dirty coal can save the Earth

    http://www.nasa.gov/topics/earth/features/warming_aerosols.html Apparently global warming is due to clean air regulations reducing the amount of acid rain in the artic and so the amount of sunlight absorbing smog.
  47. 1

    Opent top freight train with coal

    Question 3 text A freight car moves along a frictionless level railroad track at constant speed. The car is open on top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the car? Question 3 answers It increases. It remains the same. It decreases...
  48. R

    Characterising Coal Char Particles with XRD

    I want to characterise a coal char particle of size 6 to 15 mm using XRD. I am aware of powder XRD being done. But I want to subject the sample as it is as a lump particle. Is any such XRD possible. Will the XRD results of lumped sample differ from that of the powder sample? Please explain...
  49. H

    Discover the Chemical Formula for Coal Liquification | Complete Guide

    [SOLVED] Coal liquification What is the chemical formula for coal liquification?
  50. C

    Thermal efficiency of a coal powered power station

    [SOLVED] Thermal efficiency of a coal powered power station Homework Statement A company plans to build a coal powered plant for eletricity generation. The coal is to be burnt ina heat engine designed to maintain a hot resovoir temp Th, and a cold resovoir of 120 degs celcius. What is the...