Question

The production of dihydrogen obtained from coal gasification can be increased by reacting carbon monoxide of syngas mixture with steam in presence of a catalyst iron chromate. What is this process called? (a) Hydrogen reaction (b) Water-gas shift reaction (c) Coal-gas shift reaction (d) Syn gasification

Short answer

(b) Water-gas shift reaction

Step-by-step solution

Identify the Reaction

The process described involves reacting carbon monoxide (CO) with steam (H2O) to produce dihydrogen (H2) and carbon dioxide (CO2) in the presence of a catalyst, iron chromate.

Name the Reaction

This reaction is known as the water-gas shift reaction. It is a chemical reaction where water steam and carbon monoxide react to form hydrogen and carbon dioxide when in the presence of a suitable catalyst.

Choose the Correct Answer

Based on the description of the process, the correct term for this reaction is the water-gas shift reaction. Therefore, the correct answer is (b) Water-gas shift reaction.

Key concepts

Dihydrogen Production

Dihydrogen, or molecular hydrogen ((H_2)), is an energy carrier that presents a potential alternative to fossil fuels. One prevalent method of producing dihydrogen industrially is through a reaction involving coal gasification followed by the water-gas shift reaction. Coal gasification is a process that converts coal into a gas mixture known as syngas, which is primarily composed of hydrogen ((H_2)), carbon monoxide ((CO)), and carbon dioxide ((CO_2)). The syngas is then treated further to enrich the hydrogen content.

During the water-gas shift reaction, the carbon monoxide from the syngas reacts with steam ((H_2O)) in the presence of a catalyst, producing more hydrogen and carbon dioxide. This is an essential step as it enhances the yield of hydrogen. As a result, hydrogen's availability increases for use in various applications such as fuel cells or as a chemical feedstock. This method is particularly attractive as it leverages existing coal resources while transitioning towards cleaner energy systems.

Coal Gasification

Coal gasification is a thermochemical process where coal, a carbon-rich material, is transformed into syngas—a mixture primarily of hydrogen ((H_2)), carbon monoxide ((CO)), and other gases such as carbon dioxide ((CO_2)). This conversion occurs in a gasifier, where coal undergoes partial oxidation at a high temperature and pressure. Air, oxygen, or steam can act as the gasifying agent.

The benefits of coal gasification include the ability to utilize coal, which is an abundant but carbon-intensive resource, in a more efficient way compared to conventional coal burning. Moreover, the process offers versatility in generating power and heat, and in synthesizing various chemicals. When combined with processes like the water-gas shift reaction, it plays a pivotal role in producing cleaner energy carriers like dihydrogen while capturing carbon emissions more effectively.

Chemical Catalysts

Chemical catalysts are substances that increase the rate of a chemical reaction without being consumed in the reaction themselves. They achieve this by providing an alternative reaction pathway with lower activation energy. In the context of the water-gas shift reaction, the catalyst facilitates the conversion of carbon monoxide and water into dihydrogen and carbon dioxide.

Common catalysts used in this reaction include iron chromate and copper-zinc oxides. These materials are specifically chosen for their ability to withstand the high temperatures and the presence of steam without degrading. The selection of an appropriate catalyst can significantly affect the efficiency and the rate of dihydrogen production. By accelerating the reaction, catalysts make industrial processes like the water-gas shift reaction more economically viable, underpinning the large-scale production of important chemicals and fuels.