Elemental analysis of coal: Measurement principle, elemental analysis of coal: composition

The elemental analysis components of coal are: carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus.

The elemental analysis of coal is to detect and analyze the element content in coal (generally expressed by mass percentage), including conventional C, H, O, N, S, AL, SI, FE, CA and other element content, and can also detect trace elements in coal including Ti, Na, K, etc.

Elemental analysis is an important indicator to study the degree of metamorphism of coal, calculate the calorific value of coal, estimate the dry distillation products of coal, and is also the basis for calorific calculation when coal is used as fuel in industry.

The elemental composition of coal is an important indicator for studying the degree of metamorphism of coal, calorific value of coal, estimating the dry distillation products of coal, and is also the basis for calorific calculation when coal is used as fuel in industry. In addition to inorganic minerals and water, the rest of coal is organic matter.

Because the basic building unit of coal is a multi-polymer aromatic ring system with carbon as the skeleton, there are side chains and functional groups composed of carbon, hydrogen, oxygen and a small amount of nitrogen and sulfur atoms around the aromatic ring. Such as carboxyl (-cooh), hydroxyl (-OH) and methoxy (-och3). The results show that the organic matter in coal is mainly composed of carbon, hydrogen, oxygen, nitrogen, sulfur and other elements.

The degree of metamorphism of coal is different, its structural units are different, and the elemental composition is also different. The carbon content increased with the increase of the degree of metamorphism, the content of hydrogen and oxygen decreased with the increase of the degree of metamorphism, and the nitrogen and sulfur content had no relationship with the degree of metamorphism (but the amount of sulfur in the oak field was related to the paleogeological environment and conditions of coal).

Coal is a commonly used fossil energy source, and the main components are carbon, hydrogen, oxygen, nitrogen, sulfur and ash. In order to have a clearer understanding of the composition of coal and its properties, elemental analysis of coal is very important. What elements are included in the elemental analysis of coal? Let's take a closer look.

1.Carbon (c): The main component of coal is carbon, so the carbon content is essential for elemental analysis of coal. Coal above 87% is referred to as high calorific value coal, and coal below 78% is referred to as low calorific value coal.

3.Oxygen (O): Oxygen exists in the form of oxides in coal, and the organic part of coal contains different amounts of hydroxyl groups (-OH), ketone groups (C=O) and other functional groups, making oxygen an important element for elemental analysis.

4.Nitrogen (n): Despite its relatively low levels in coal, nitrogen is still a critical element in the elemental analysis of coal and can be quantified by looking at coal sections using a Shore microscope.

5.Sulfur (S): The amount of sulfur in coal not only affects its use value, but can also lead to environmental pollution. Therefore, it is necessary to determine the sulfur content in coal.

6.Chlorine (Cl): Chlorine can be quantified by elemental analysis techniques, but generally only its corrosion of coal is considered.

7.Phosphorus (p): The amount of phosphorus can also be determined by elemental analysis. During combustion, phosphorus (as well as other elements) remains in the ash.

In summary, the elemental analysis of coal includes key elements such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), chlorine (Cl), and phosphorus (P). The content and proportion of these elements determine the physical and chemical properties of coal, and directly affect the characteristics of fuel, utilization efficiency and environmental protection, etc., which are of great practical significance in the process of coal mining, storage and transportation, and the utilization of coal front.

What are the items involved in the elemental analysis of coal?

Elemental analysis of coal is the determination of important elements such as carbon, hydrogen, oxygen, nitrogen and sulfur in coal.

1) Carbon and hydrogen.

Carbon and hydrogen are the main components of coal and can release a lot of heat when burned. In general, the elements of organic matter in coal change regularly with the degree of coalification. The higher the degree of coalification, the higher the carbon content, while the lower the hydrogen and oxygen content.

2) Oxygen. Oxygen in coal is a combustion element, and its content decreases with the deepening of coalification.

3) Nitrogen. The nitrogen content in coal is not high, generally below 2. When the nitrogen in coal is burned, it forms harmful gases such as nitrogen oxides, which pollute the atmosphere.

4) Sulfur. The sulfur in coal is a harmful impurity, and the content is generally in. Sulfur in coal is divided into organic sulfur and inorganic sulfur. Organosulfur is entered into coal along with organic matter during coal formation. Inorganic sulfur is further divided into iron sulfide (pyrite) sulfur and sulfate sulfur.

The sulfur in coal forms SO2 when burned, polluting the atmosphere. SO2 forms acid rain under the action of light and heat, corroding metals and equipment, and harming plant growth. The sulfur is transferred to the coke during the coking process, and the sulfur in the coke is transferred to the iron during the ironmaking, making the iron brittle.

Therefore, sulfur is an important index to evaluate coal quality. Iron sulphur can be partially removed from coal washing, while sulphur sulphur and organosulphur can only be removed during combustion or in the purified flue gas.

Coal testing includes coal sampling, shrinkage, crushing, sample preparation, and coal testing.

Coal assay is a new generation of instruments developed to detect the content of various elements in coal. Main test items: total sulfur, calorific value, moisture of coal (total moisture, analytical water), ash, volatile, fixed carbon, carbon, hydrogen, ash meltability, slag carbon content, coking coal, petroleum coke, briquette and other related items.