Difference Between Proximate analysis and Ultimate analysis

Difference Between Proximate analysis and Ultimate analysis

Proximate analysis of coal is the process of determining the presence of different compounds and their amounts in coal. Ultimate analysis of coal, on the other hand, is the process of determining different chemical elements present in coal. Therefore, the key difference between proximate and ultimate analysis of coal is that proximate analysis of coal is the technique used to analyze the moisture content, ash content, and fixed carbon content of coal whereas ultimate analysis of coal is the technique used to analyze the chemical composition of coal.

Coal is an abundant natural resource that can be used as a source of energy. The chemical analysis of coal includes both Proximate and Ultimate analysis. Proximate analysis of coal examines the chemical composition of a coal sample. The proximity analysis parameters are

1) Moisture,

2) Volatile compounds,

3) Ash content

4) Fixed carbon.

Proximate analysis is used to ascertain the “Rank” of coals as the above parameters will indicate the Heating value of the coal.

Whereas Ultimate analysis, which is more comprehensive, is dependent on quantitative analysis of various elements present in the coal sample such as carbon, hydrogen, sulfur, oxygen, and nitrogen.

  • Proximate analysis of coal determines the moisture content of coal, volatile matter, ash content, and fixed carbon of coal. Ultimate analysis determines the chemical composition of coal i.e Carbon, hydrogen, oxygen, nitrogen, sulfur along with moisture and ash.
  • Proximate analysis is useful for finding out the heating value of coal and ultimate analysis is helpful for determining flame temperature and flue gas duct design.

The key difference between proximate and ultimate analysis is that proximate analysis is the technique used to analyze the compounds in a mixture, whereas ultimate analysis is the technique used to analyze the elements present in a compound.

Proximate Analysis

The proximate analysis consists of the determination of ash content, moisture content, volatile matter, and fixed carbon on an as-received basis. Usually, a calorific value is also required with proximate analysis. Total moisture includes air-dry loss moisture and inherent moisture.

Proximate analysis refers to the quantitative analysis of macromolecules in food. A combination of different techniques, such as extraction, Kjeldahl, and NIR is used to determine protein, fat, moisture, ash, and carbohydrates levels. With the guidebook, benefit from:

  • A decision tree for selecting fat extraction equipment
  • Different NIR possibilities for liquid and solid sample analysis
  • What you need for protein determination by the Kjeldahl method
  • Example of proximate analysis of dairy products from farmer to the final product

The proximate analysis of coal separates the products into four groups: 

(1) moisture, 

(2) volatile matter, consisting of gases and vapors driven off during pyrolysis, 

(3) fixed carbon, the nonvolatile fraction of coal, and

(4) ash, the inorganic residue remaining after combustion.

'Proximate Analysis' makes available a variety of equipment necessary for sample preparation (balances, centrifuges, freeze dryers, drying ovens, etc.) and for the determination of the crude composition of foods and feedstuffs, similar to that presented in the table below.

The proximate composition of foods includes moisture, ash, lipid, protein, and carbohydrate contents. These food components may be of interest in the food industry for product development, quality control (QC), or regulatory purposes. Analyses used may be rapid methods for QC or more accurate but time-consuming official methods. Sample collection and preparation must be considered carefully to ensure the analysis of a homogeneous and representative sample, and to obtain accurate results. Estimation methods of moisture content, ash value, crude lipid, total carbohydrates, starch, total free amino acids, and total proteins are put together in a lucid manner.

Ultimate Analysis

The ultimate analysis is defined as the determination of carbon, hydrogen, nitrogen, and sulfur in a wide type of organic and inorganic samples, both solid and liquid. For this analysis, a coal sample is combusted in an ultimate analyzer, which measures the weight percent of carbon, hydrogen, nitrogen, sulfur, and ash from a coal sample. The total carbon, hydrogen, and nitrogen are determined at the same time from the same sample in the analyzer.

The ultimate analysis of coal involves the determination of the weight percent carbon as well as sulfur, nitrogen, and oxygen (usually estimated by difference). Trace elements that occur in coal are typically included as a part of the ultimate analysis.

The ultimate analysis provides a convenient method for reporting the major organic elemental composition of coal. For this analysis, a coal sample is combusted in an ultimate analyzer, which measures the weight percent of carbon, hydrogen, nitrogen, sulfur, and ash from a coal sample. The ultimate analysis informs about the amount of carbon (C), hydrogen (H), nitrogen (N), sulfur (S), and oxygen (O). Also, thermal characteristics such as heating value, in particular the higher heating value (HHV), are a key factor for the design of WTE plants.

Proximate analysisUltimate analysis
Proximate analysis of coal is an assay of the quantity of the coal.The ultimate analysis is the element analysis of the coal.
The various parameter studied are percentages of moisture, volatile matter, ash, and fixed carbon.The various parameters studied are percentages of carbon, hydrogen, sulfur, nitrogen, ash, and oxygen.
The analysis is cheap and the process is fast.The analysis is comparatively costly and the process is slow.
It is used for classification, the gradation of coal, and predicting its industrial use.It is used to find the calorific value of the coal and heat balance sheets.
HardnessWater softening
Pathogenic bacteria.Disinfection

Fixed carbon from the proximate analysis is a different value than total carbon from the ultimate analysis. Total carbon includes some organic carbon that escapes as volatile matter emissions during combustion. Fixed-carbon content increases with rank and is used to define ranks above medium-volatile bituminous coal. Fixed carbon has the opposite trend of volatile matter with increasing rank because increases in the amount of volatile matter driven off of coal increase the relative amount of carbon. Fixed-carbon content is also an important criterion for estimating the amount of coke that can be distilled from coal. Coke is a high-carbon product used in steel production.

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