Sage-Tips

What is the purpose of coal liquefaction?

The principal objective of coal liquefaction is the production of liquid hydrocarbon distillate products from a coal’s mostly aromatic structure to be used as transportation fuels or chemicals.

How is coal gasified?

Gasification of coal is a process in which coal is partially oxidated by air, oxygen, steam or carbon dioxide under controlled conditions to produce a fuel gas. The hot fuel gas is cooled in heat exchangers, with the production of steam, and cleaned before combustion in a gas turbine.

What is direct liquefaction of coal?

Direct coal liquefaction involves contacting coal directly with a catalyst at elevated temperatures and pressures with added hydrogen (H2), in the presence of a solvent to form a raw liquid product which is further refined into product liquid fuels.

What is the difference between coal gasification and coal liquefaction?

The process involves gasification of coal, which in turn will produce synthetic gas (a mix of CO+H2). However, liquefied coal emits twice as much CO2 as burning oil. It also emits a large volume of SO2.

How is solvent refined coal obtained?

Solvent refined coal (SRC), a coal extract which is highly polyaromatic in character and relatively high in N, O and S content, is derived from the direct liquefaction of coal. SRC contains mineral matter in the form of soluble organometallic compounds which can not be removed by filtration.

Why is coal solid and oil liquid?

Coal is a solid, oil is a liquid and natural gas is a vapor (gas). Basically, coal is purely vegetation in strata. It is always “longer-chain” hydrocarbons. Oil may be formed from animal as well as plant decomposition, and has relatively shorter hydrocarbon chains, making it a liquid instead of a solid.

Why is coal gasified?

In current practice, large-scale coal gasification installations are primarily for electricity generation, or for production of chemical feedstocks. The hydrogen obtained from coal gasification can be used for various purposes such as making ammonia, powering a hydrogen economy, or upgrading fossil fuels.

What is the purpose of gasification?

Gasification is a process that converts organic or fossil-based carbonaceous materials at high temperatures (>700°C), without combustion, with a controlled amount of oxygen and/or steam into carbon monoxide, hydrogen, and carbon dioxide.

What is the process of coal liquefaction?

coal liquefaction, any process of turning coal into liquid products resembling crude oil. The two procedures that have been most extensively evaluated are carbonization—heating coal in the absence of air—and hydrogenation—causing coal to react with hydrogen at high pressures, usually in the presence of a catalyst.

What is liquefaction process?

In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially.

Why do we use coal gasification process?

The hydrogen obtained from coal gasification can be used for various purposes such as making ammonia, powering a hydrogen economy, or upgrading fossil fuels. Natural gas from coal gasification can be cooled until it liquifies for use as a fuel in the transport sector.

Why is coal refined?

A primary benefit of refined coal is the capacity to reduce the net volume of carbon emissions that is currently emitted from power generators and would reduce the amount of emissions that is proposed to be managed via emerging carbon sequestration methodologies. …

What is the process of liquefaction of coal?

Coal liquefaction, any process of turning coal into liquid products resembling crude oil. The two procedures that have been most extensively evaluated are carbonization—heating coal in the absence of air—and hydrogenation—causing coal to react with hydrogen at high pressures, usually in the presence of a catalyst.

What is indirect coal liquefaction (ICL)?

The latter two-step approach, i.e. the coal to syngas to liquids route is termed indirect coal liquefaction (ICL). Therefore, the DCL process is, in principle, the simpler and more efficient of the two processes.

What is hyhybrid coal liquefaction?

Hybrid process approaches involving a combination of direct coal liquefaction and indirect coal liquefaction (in which gasification is an intrinsic step) have been proposed and may be increasingly important in new research and development in coal/biomass to liquids process technology.

What are the different types of liquefaction processes?

There are also a number of two-stage direct liquefaction processes; however, after the 1980s only the Catalytic Two-stage Liquefaction Process, modified from the H-Coal Process; the Liquid Solvent Extraction Process by British Coal; and the Brown Coal Liquefaction Process of Japan have been developed.