Coal and Hydrogen (6-7) Flashcards
Anthracite -The transition from bituminous coal to anthracite is marked by a
progressive loss of _____ properties, due to decreasing ________
content.
The transition from bituminous coal to anthracite is marked by a
progressive loss of coking properties, due to decreasing volatile
content
Resource?
Resources of a commodity such as coal are those quantities that are
likely to exist, but may not be exploitable at this time due to a
combination of factors
Reserve?
Reserves of a commodity such as coal are those quantities that can
be exploitable at this time due to a combination of factors including
market price and technology
________ are a subset of Resources
Reserves are a subset of Resources
Coalification
Coalification involves the loss of water and volatile components in
the form of CO2 and CH4 and an increase in carbon content, from
about 60 per cent in peat to more than 90 per cent in bituminous
coal and 95 per cent in anthracite. Used as ranking system with calorific value.
Relate this equation to density –> P1V1 = P2V2
P1/p1 = P2/p2
Hydrogen storage challenges
The key challenges include:
1. Weight and Volume.
2. Efficiency.
3. Durability. Materials and components are needed that allow hydrogen storage
systems with a lifetime of 1500 cycles.
4. Refuelling Time. less than three minutes over the lifetime of the system.
5. Cost.
6. Codes and Standards. Standardized hardware and operating procedures, and applicable codes and standards, are required.
7. Life‐Cycle and Efficiency Analyses. There is
a lack of analyses of the full life ‐cycle cost and efficiency for hydrogen storage systems.
Ignition energy?
- Ignition energy is the amount of external energy that must be applied in order to
ignite a combustible fuel mixture. Common ignition sources are flames and sparks.
Fire point?
The fire point, or combustion point, of a fuel is the lowest temperature at which the vapour of that fuel will continue to burn for at least five seconds after ignition by an open flame of standard dimension.
How is coal formed?
Fossil fuels (coal, oil and natural gas) are formed from organic
matter that has accumulated over geological timeframes and has
subsequently undergone a range of transformations. It is formed by the
alteration of dead plant material (anaerobic breakdown) that initially accumulates as a surficial deposit of peat and is then buried beneath layers of younger
sediment. As the temperature rises, due to increasing depth of burial,
the initial peat may be sequentially altered by the process of
coalification.
Place in order of rank, highest to lowest
Anthracites
Lignites
Bituminous coals
Sub-bituminous coals
Anthracites
Bituminous coals
Sub-bituminous coals
Lignites
Why is high sulphur content 3% bad in coal ?
- Combustion of coal releases the sulphur as SO2 which is an
undesirable pollutant as it forms Acid Rain - Additional sulphur from sulphates can accumulate from marine
flooding
What gives coal a better rank?
The higher the pressure it was under, i.e. depth of burial and potential folding pressure of the earths crust, reduces water content in the coal by increasing the temperature during its formation.
Moisture is found in coal in two different forms, what are they? [2]
a) Inherent moisture ‐ absorbed or adsorbed within the coal substance.
b) Surface (or free) moisture ‐ lies on the surface ‐ may be acquired during water
spraying (suppression of dust during mining), wet washing, or exposure in the open
to rain and snow.
Coal analysis techniques Describe 2?
- Proximate Analysis
The proximate analysis involves the determination of:
* equilibrium moisture which is evolved at 105 °C
* the volatile matter (VM) released on slow heating to 925 °C in a closed crucible
* the ash residue on combustion at 800 °C
* and the fixed carbon (FC) as the balance of the assay - Heating Value
The heating value (calorific calorimeter value) is determined by combustion in an adiabatic bomb.
