What is G index in coking coal?
The value of G characterizes the content of active component of coal, and is considered as a measure of the degree of reduction of coal. The method using a plot of the volatile matter content (V, d.a.f.) vs. G can predict the coke strength and permits selection of the best economic coal blending ratios.
What is y index in coal?
The Y value is the maximum difference between the upper and lower plastic layer levels expressed in mm. Y values will typically range from 5-35mm. The X value equals the percent contraction, or shrinkage, of the coal brickette during the test. X values generally range from 0-35%.
What is the density of coking coal?
Density. Knowledge of the physical properties of coal is important in coal preparation and utilization. For example, coal density ranges from approximately 1.1 to about 1.5 megagrams per cubic metre, or grams per cubic centimetre (1 megagram per cubic metre equals 1 gram per cubic centimetre).
Which is the best quality of coking coal?
Coking refers to the coal’s ability to be converted into coke, a pure form of carbon that can be used in basic oxygen furnaces. Bituminous coal—generally classified as metallurgical grade—is harder and blacker and contains more carbon and less moisture and ash than low-rank coals.
What is difference between coking and non coking coal?
Noncoking coals have higher ash content and are typically used in thermal power plants as steam coals. Coking coal is the type of coal which on heating in the absence of air undergoes a transformation into a plastic state, swells, and then solidifies to form coke.
What is soft coking coal?
The semi-soft coking coal (also known as medium/weak coking coal) is used in the coal blends along with hard coking coal. Coal for PCI is used for its heat value and injected directly into the blast furnace as a replacement for coke.
Is PCI coking coal?
PCI (pulverised coal injection) coal is essentially high-quality thermal coal which can be sold into metallurgical or thermal coal markets alike. It’s injected into historically dominant blast furnaces to reduce more expensive coking coal consumption.
What is specific gravity of coal?
Coal Resource Classification System of the U.S. Geological Survey
| Weight of unbroken coal per unit volume | ||
|---|---|---|
| Rank | Specific gravity | Metric tons per square hectometermeter |
| Anthracite and semianthracite | 1.47 | 1,470,000 |
| Bituminous coal | 1.32 | 1,320,000 |
| Subbituminous coal | 1.30 | 1,300,000 |
What are the 3 types of coal?
What are the types of coal?
- Anthracite: The highest rank of coal.
- Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite.
- Subbituminous: Subbituminous coal is black in color and is mainly dull (not shiny).
What is the difference between metallurgical coal and coking coal?
Coking coal, also known as metallurgical coal, is used exclusively as an essential ingredient for steel production. The coal is ‘baked’ in a coke oven which forces out impurities to produce coke, which is a form of almost pure carbon.
Which country is the largest producer of coking coal?
China
China is the largest coal-producing country in the world, with production reaching 3,942 million tonnes, a 2.5% growth. The country’s coal mine production is expected to remain flat, at a CAGR of just 1.1% between 2021 and 2025, to reach 4.1 billion tonnes in 2025.
Can steel be made without coking coal?
Coking coal is usually bituminous-rank coal with special qualities that are needed in the blast furnace. While an increasing amount of steel is being recycled, there is currently no technology to make steel at scale without using coal.
Why is it called coking coal?
The industrial production of coke from coal is called coking. The coal is baked in an airless kiln, a “coke furnace” or “coking oven”, at temperatures as high as 2,000 °C (3,600 °F) but usually around 1,000–1,100 °C (1,800–2,000 °F).
How many types of coking coal are there?
Hard coking coals (HCC) Medium coking coal (MCC) Semi-soft coking coal (SSCC) Pulverized coal for injection (PCI) coal.
What is PCI coke?
Pulverized Coal Injection (PCI) is a process that involves blowing large volumes of fine coal granules into the BF. This provides a supplemental carbon source to speed up the production of metallic iron, reducing the need for coke production. As a result energy use and emissions can be reduced.
What type of coal is used in PCI?
thermal coals
As combustibility was considered to be of importance, the coals used for PCI were thermal coals. At that time, thermal coals were readily available and had a much lower cost than hard coking and semi-soft coking coals.
What are 4 types of coal?
Coal is classified into four main types, or ranks: anthracite, bituminous, subbituminous, and lignite. The ranking depends on the types and amounts of carbon the coal contains and on the amount of heat energy the coal can produce.
What is specific gravity unit?
It has the SI unit kg m-3 or kg/m3 and is an absolute quantity. Specific gravity is the ratio of a material’s density with that of water at 4 °C (where it is most dense and is taken to have the value 999.974 kg m-3). It is therefore a relative quantity with no units.
Which is the lowest quality of coal?
Lignite or brown coal is the lowest grade coal. Lignite has a low heating value and a high moisture content. It has the least concentration of carbon and is mainly used in electricity generation.
What is the cleanest type of coal?
Anthracite
Anthracite is used for space heating as it is one of the cleanest types of coal to burn—producing less smoke than other types. Its clean burning properties allows anthracite to burn longer than wood, making it appealing to use in home heating stoves.
What is the best coal in the world?
Anthracite, also known as hard coal, and black coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
Which country has the cleanest coal?
Australian coal is generally amongst the best quality coal in the world, regarded highly for its energy content, low impurity and its efficiency as a coking agent in the production of steel.
Is there an alternative to coking coal?
This one is obvious – renewables! Blast furnaces need coal, but there is an alternative technology called an Electric Arc Furnace (EAF). This is responsible for approximately 30% of the world’s steel production and does not require coal.
How is PCI coal made?
The PCI process is based on the simple concept of carrying the finely ground (pulverized) dried coal by a conveying gas (normally nitrogen) to the BF where it is distributed to different tuyeres and injected through a lance in the blow pipe.
What is the difference between thermal coal and coking coal?
Thermal coal, also called steaming coal, has a lower energy content and higher moisture and is used to generate electricity. Metallurgical or coking coal has a higher energy content and lower moisture and is used to make iron, steel and other metals.