Chapter 22: Problem 24
List (a) three commercial means of producing \(\mathrm{H}_{2}\), (b) three industrial uses of \(\mathrm{H}_{2}\).
Short Answer
Expert verified
Commercial means of producing H2: (a) Steam Methane Reforming, (b) Electrolysis, and (c) Coal Gasification.
Industrial uses of H2: (1) Hydrogenation in the food industry, (2) Ammonia production for fertilizers, and (3) Refining and processing of petroleum.
Step by step solution
01
Commercial Means of Producing H2 (Part a)
1. Steam Methane Reforming: In this process, methane (CH4) from natural gas is combined with steam under high temperature and pressure to produce hydrogen (H2) and carbon monoxide (CO). The carbon monoxide is then combined with steam to produce additional H2 and carbon dioxide (CO2).
2. Electrolysis: This method involves passing an electric current through water (H2O) to split it into hydrogen (H2) and oxygen (O2) gases. Electrolysis requires a significant amount of electrical energy, but it produces pure hydrogen gas.
3. Coal Gasification: In this process, coal is heated under pressure in the presence of oxygen and steam to produce synthesis gas, which is a mixture of hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2). The hydrogen gas can then be separated from the synthesis gas for further use.
02
Industrial Uses of H2 (Part b)
1. Hydrogenation in the Food Industry: Hydrogen gas is used to convert unsaturated fats and oils into saturated fats and oils by adding hydrogen molecules to the carbon-carbon double bonds. This process, called hydrogenation, is widely used in the food industry to make products like margarine and vegetable shortening.
2. Ammonia Production for Fertilizers: Hydrogen gas is a key ingredient in the production of ammonia (NH3), which is an essential component of many fertilizers. The Haber-Bosch process combines hydrogen (H2) with nitrogen (N2) under high pressure and temperature to produce ammonia (NH3).
3. Refining and Processing of Petroleum: Hydrogen gas is used extensively in the petroleum industry for refining and processing crude oil. It is used for hydrocracking and hydrotreating processes, which help to break down heavy hydrocarbons into lighter, more valuable products like gasoline and diesel fuel, and also remove impurities like sulfur and nitrogen from the final products.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Steam Methane Reforming
Steam Methane Reforming (SMR) is a dominant method for hydrogen production on a commercial scale. It involves using natural gas, primarily methane, as a feedstock.
Under high temperatures (700-1100°C) and pressure, methane reacts with steam to form hydrogen (H2) and carbon monoxide (CO). This process is represented by the chemical equation:
Efforts are being made to integrate carbon capture technologies to mitigate these emissions.
Under high temperatures (700-1100°C) and pressure, methane reacts with steam to form hydrogen (H2) and carbon monoxide (CO). This process is represented by the chemical equation:
- \[ \text{CH}_4 + \text{H}_2\text{O} \rightarrow \text{CO} + 3 \text{H}_2 \]
- \[ \text{CO} + \text{H}_2\text{O} \rightarrow \text{CO}_2 + \text{H}_2 \]
Efforts are being made to integrate carbon capture technologies to mitigate these emissions.
Electrolysis of Water
Electrolysis of water is a clean and straightforward method of producing hydrogen, though it requires substantial energy input. It involves using electrical energy to split water (\( \text{H}_2\text{O}\) into its elemental components, hydrogen (\(\text{H}_2\)) and oxygen (\(\text{O}_2\)).
This is achieved by passing an electric current through water containing an electrolyte to improve conductivity.
The key reaction is:
Moreover, if the electricity used is generated from renewable sources, it can be a highly sustainable and eco-friendly process.
This is achieved by passing an electric current through water containing an electrolyte to improve conductivity.
The key reaction is:
- \[ 2 \text{H}_2\text{O}(l) \rightarrow 2 \text{H}_2}(g) + \text{O}_2}(g) \]
Moreover, if the electricity used is generated from renewable sources, it can be a highly sustainable and eco-friendly process.
Coal Gasification
Coal Gasification is a process where coal is converted into gaseous products in the presence of oxygen and steam.
This transformation occurs under high temperature and pressure, producing what is known as synthesis gas or syngas.
The syngas is primarily a mixture of hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2).
Significant reactions include:
Though coal gasification enables the use of available coal resources, it poses challenges regarding CO2 emissions and energy efficiency.
This transformation occurs under high temperature and pressure, producing what is known as synthesis gas or syngas.
The syngas is primarily a mixture of hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2).
Significant reactions include:
- \[ \text{C} + \text{H}_2\text{O} \rightarrow \text{CO} + \text{H}_2 \]
- \[ \text{C} + \frac{1}{2} \text{O}_2 \rightarrow \text{CO} \]
Though coal gasification enables the use of available coal resources, it poses challenges regarding CO2 emissions and energy efficiency.
Industrial Uses of Hydrogen
Hydrogen is a versatile industrial gas with a range of applications. One of its primary uses is in hydrogenation processes in the food industry.
This involves converting unsaturated fats into saturated fats, enhancing the stability and shelf life of food products.
Another critical application is in the synthesis of ammonia for fertilizers via the Haber-Bosch process, which combines hydrogen and nitrogen.
Ammonia is essential for agricultural productivity, highlighting the importance of hydrogen in food security.
The petroleum industry also heavily relies on hydrogen for refining and processing crude oils.
It plays a key role in hydrocracking and hydrotreating, where larger molecules are broken down into valuable fuels, and impurities like sulfur are removed.
This makes fuels cleaner and improves their quality.
This involves converting unsaturated fats into saturated fats, enhancing the stability and shelf life of food products.
Another critical application is in the synthesis of ammonia for fertilizers via the Haber-Bosch process, which combines hydrogen and nitrogen.
Ammonia is essential for agricultural productivity, highlighting the importance of hydrogen in food security.
The petroleum industry also heavily relies on hydrogen for refining and processing crude oils.
It plays a key role in hydrocracking and hydrotreating, where larger molecules are broken down into valuable fuels, and impurities like sulfur are removed.
This makes fuels cleaner and improves their quality.
Haber-Bosch Process
The Haber-Bosch Process is a critical industrial method for the large-scale synthesis of ammonia (\(\text{NH}_3\)), which is vital for fertilizers.
Developed in the early 20th century, it enabled the mass production of fertilizers, significantly boosting agricultural output globally.
The process involves the reaction of nitrogen (\(\text{N}_2\)) from the air with hydrogen (\(\text{H}_2\)) under high pressure (150-200 atmospheres) and temperature (400-500°C), in the presence of a metal catalyst, typically iron.
The balanced chemical equation for the process is:
Its importance cannot be overstated, as it supports the global food supply by providing essential nutrients through fertilizers.
Developed in the early 20th century, it enabled the mass production of fertilizers, significantly boosting agricultural output globally.
The process involves the reaction of nitrogen (\(\text{N}_2\)) from the air with hydrogen (\(\text{H}_2\)) under high pressure (150-200 atmospheres) and temperature (400-500°C), in the presence of a metal catalyst, typically iron.
The balanced chemical equation for the process is:
- \[ \text{N}_2(g) + 3\text{H}_2(g) \rightarrow 2 \text{NH}_3(g) \]
Its importance cannot be overstated, as it supports the global food supply by providing essential nutrients through fertilizers.