What are the three types of macerals?
The three maceral groups are vitrinite, liptinite and inertinite. The vitrinite maceral group, usually, makes up the major proportion of most coals.
What is vitrinite composed of?
Chemically, it is composed of polymers, cellulose and lignin. The vitrinite group, which consists of various individual vitrinite macerals, is the most common component of coals. It is also abundant in kerogens that are derived from the same biogenic precursors as coals, namely land plants and humic peats.
What is maceral group?
maceral, any of the numerous microscopically recognizable, individual organic constituents of coal with characteristic physical and chemical properties. Macerals are classified into three major groups: vitrinite, inertinite, and liptinite (formerly called exinite).
What is macerals in coal?
On the microscopic level, coal is made up of organic particles called macerals. Macerals are the altered remains and byproducts of the original plant material from which the coal-forming peat originated. Macerals are to coal as sediment grains and cements are to sedimentary rocks.
What is petrography of coal?
Coal petrography is a microscopic technique used to determine a coals rank (degree of coalification) and type (amount and type of macerals) on polished specimens of minus 20 mesh prepared coal. Rank is determined by measuring the percent light reflectance of the maceral vitrinite.
Is lignite A coal?
Lignite: Lignite coal, aka brown coal, is the lowest grade coal with the least concentration of carbon. Lignite has a low heating value and a high moisture content and is mainly used in electricity generation.
What is Catagenesis petroleum?
Catagenesis is a term used in petroleum geology to describe the cracking process which results in the conversion of organic kerogens into hydrocarbons.
What role does kerogen play in generation?
Kerogen takes on additional importance in unconventional resources, particularly shale. In these formations, oil and gas are produced directly from the kerogen-rich source rock (i.e. the source rock is also the reservoir rock). Thus, kerogen controls much of the storage and transport of oil and gas in shale.
What is vitrain clarain durain Fusain?
durain, macroscopically distinguishable component, or lithotype, of coal characterized by a hard, granular texture and composed of the maceral groups exinite and inertinite as well as relatively large amounts of inorganic minerals. See also clarain; fusain; vitrain; maceral.
What is coal petrography?
What is a Microlithotype?
Microlithotypes (Table 2.5) are the natural assemblages of macerals at microscopic level. They are defined as having a minimum bandwidth (perpendicular to the stratification) of 50 μm and as containing at least 5% of a maceral group (ICCP, 1963, 1971, and Taylor et al., 1998).
How coal is Analysed?
Total sulfur (part of ultimate analysis) Trace element: determines the elemental composition of coal and coal ash. Ultimate analysis: determines amounts of the major elements in coal: carbon, hydrogen, nitrogen, sulfur, oxygen. Vitrinite reflectance (Ro): determines the relative rank of coal.
What are the components of Liptinites?
Liptinites usually make up less than 20% of the coal mass. They contain the more aliphatic fossilized components, chiefly sporinite (spores and pollen), cutinite (cuticles, waxes), resinite (fossil resins) and the highly paraffinic alginite [ Stach, 1982; van Krevelen, 1993 ].
What is the origin of liptinite maceral?
The liptinite maceral group makes up 5–20% of the coals in question. Its origin is plant resins, spores, and pollens, resinous and waxy materials that give rise to macerals rich in hydrogen and aliphatic structures. Terpenes and plant lipid resins give rise to the varied group of resinite macerals.
How much liptinite is present in feed coals?
In most cases, liptinite is present in low amounts (ca. 10%) in feed coals. Therefore, its influence during combustion is generally neglected.
Why should liptinite be considered during combustion?
Another reason that liptinite should be considered during combustion, is that standard proximate analysis for measuring volatile matter in coals may yield values that are half of those obtained under conditions of pulverised coal because the conditions of this one include higher temperature and heating rate [170].