What is the Difference Between Coal Carbonization and Gasification

The key difference between coal carbonization and gasification is that coal carbonization is the liberation of volatile products from coal upon heating, whereas gasification is the conversion of biomass into producer gas (syngas) upon heating.

Coal carbonization and gasification are important industrial processes that include coal as the main reactant. These processes give important residues upon heat treatment.

CONTENTS

1. Overview and Key Difference
2. What is Coal Carbonization  
3. What is Gasification
4. Coal Carbonization vs Gasification in Tabular Form
5. Summary – Coal Carbonization vs Gasification 

What is Coal Carbonization?

Coal carbonization is the process of heating coal, which causes the volatile products to liberate from coal, leaving off a solid residue. This solid residue is named coke. The volatile products in coal can be liquids or gases, or it can be both. In this process, we need to heat coal to a high temperature. We can do this heating either in the absence of oxygen or in a controlled level of oxygen gas.

Figure 01: Carbonization

Usually, the term carbonization refers to the conversion of organic matter (such as plants and dead animal materials) into carbon through an analytical process called destructive distillation. Destructive distillation is the decomposition of unprocessed material using heat, followed by proper extraction.

The process of carbonization occurs as a pyrolytic reaction, and it is a complex process where several chemical reactions occur concurrently. These reactions include dehydrogenation, condensation, hydrogen transfer, and isomerization.

Moreover, carbonization is different from coalification because coalification is comparatively very fast due to the high reaction rate.

What is Gasification?

Gasification is a thermo-chemical process that converts biomass into a combustible gas called producer gas (syngas). Here, the materials decompose in an environment where a small amount of oxygen is present. However, this amount of oxygen is not enough for combustion. The products of gasification are heat and combustible gas.

Moreover, the process proceeds at temperatures ranging from 800°C – 1200°C. The principal components in the combustible gas formed during this process include carbon monoxide and hydrogen gas. In addition, there are some other components such as water vapour, carbon dioxide, tar vapour, and ash.

Figure 02: Different Types of Gasifiers

In a gasifier where the gasification takes place at the industrial level, we can use different types of feedstock; we can classify these according to the characteristics such as size, shape, bulk density, moisture content, energy content, chemical composition, homogeneity, etc. The feedstock types include waste disposal such as waste wood, pellets and chips, plastics and aluminum, sewage sludge, etc.

What is the Difference Between Coal Carbonization and Gasification?

Coal carbonization and gasification are important industrial processes that include coal as the main reactant. The key difference between coal carbonization and gasification is that coal carbonization is the liberation of volatile products from coal upon heating, whereas gasification is the conversion of biomass into syngas upon heating. Moreover, the end products of coal carbonization are coke, coal tar, soot, and hydrocarbon gases, while the end products of gasification are solids, ash, slags, and syngas.

The below infographic lists the differences between coal carbonization and gasification in tabular form for side by side comparison.

Summary – Coal Carbonization vs Gasification

In the hydrocarbon industry, coal is an important reactant that can undergo several different processes, such as carbonization and gasification. The key difference between coal carbonization and gasification is that coal carbonization is the liberation of volatile products from coal upon heating, whereas gasification is the conversion of biomass into syngas upon heating.

Reference:

1. “Gasification.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Carbonization Link Map – 1” By IUPAC – (Public Domain) via Commons Wikimedia
2. “Gasifier types” By Kopiersperre – Own work (CC BY-SA 3.0) via Commons Wikimedia

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