Hydrogen - Introduction, Production Process, Color Codes, Applications

INTRODUCTION :-

Hydrogen is the simplest and most abundant element on earth it consists of only one proton and one electron. It's the most abundant chemical element, estimated to contribute 75% of the mass of the universe. On earth, vast numbers of hydrogen atoms are contained in water, oil, natural gas and all living matter. Despite its simplicity and abundance, It doesn't typically exist by itself in nature. Hydrogen rarely occurs naturally as a gas on Earth. It is almost always combined with other elements and must be produced from compounds that contain it. It is light, storable, energy-dense, and produces no direct emissions of pollutants or greenhouse gases. Hydrogen powered the first internal combustion engines over 200 years ago and now it is an integral part of the modern refining industry. Hydrogen is an energy carrier, not an energy source that can be used to move, store, and deliver energy produced from other sources. It stores three times as much energy per unit of mass as conventional petrol.

Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water. Once hydrogen is produced as molecular hydrogen, the energy present within the molecule can be released, by reacting with oxygen to produce water. This can be achieved by devices called fuel cells. In a fuel cell, hydrogen energy is converted directly into electricity with high efficiency and low power losses. When it “burns” in air releasing that stored energy it simply combines with oxygen to produce water again. Hydrogen can be produced from a variety of domestic resources, such as natural gas, nuclear power, biomass and by splitting water using renewable solar or electrical energy. However, 96 per cent of hydrogen today is made directly from fossil fuels mostly natural gas, followed by coal and then oil. While less than 0.1% of global dedicated hydrogen production today comes from water electrolysis. Industries supports the research and development of a wide range of technologies to produce hydrogen economically and via net-zero-carbon pathways.

PRODUCTION OF HYDROGEN :-

Today, hydrogen fuel can be produced through several methods. The most common methods today are thermal process and electrolysis. Other methods include solar driven and biological processes.

THERMAL PROCESSES :-

In Thermal processes for hydrogen production, steam reacts with a hydrocarbon fuel to produce hydrogen. Many hydrocarbon fuels can be used to produce hydrogen, including natural gas, diesel, renewable liquid fuels, gasified coal, or gasified biomass. Process uses high temperatures from concentrated solar power or from the waste heat of nuclear power reactions and chemical reactions to produce hydrogen and oxygen from water. The chemicals used in the process are reused within each cycle, creating a closed loop that consumes only water and produces hydrogen and oxygen. Today, about 95% of all hydrogen is produced from steam reforming of natural gas.

ELECTROLYTIC PROCESSES :-

Water electrolysis is the decomposition of water into its basic components, hydrogen and oxygen through passing electric current. Through this process, electrical energy can be stored as chemical energy of the resulting hydrogen. This reaction takes place in a unit called an electrolyzer. Electrolyzers can range in size from small to large. Electrolyzer functions much like a fuel cell in reverse instead of using the energy of a hydrogen molecule, an electrolyzer creates hydrogen from water molecules. Like fuel cells, electrolyzers consist of an anode and a cathode separated by an electrolyte.

SOLAR-DRIVEN PROCESSES :-

Solar-driven processes use sun light as the agent for hydrogen production. There are a few solar-driven processes, including photobiological, photoelectrochemical, and solar thermochemical. Photobiological processes use the natural photosynthetic activity of bacteria and green algae. Photoelectrochemical processes use specialized semiconductors to separate water into hydrogen and oxygen. Solar thermochemical hydrogen production uses concentrated solar power to drive water splitting reactions often along with other species such as metal oxides.

BIOLOGICAL PROCESSES :-

The photobiological hydrogen production process uses bacteria, microorganisms and sunlight to produce hydrogen through biological reactions. This technology is in the early stages of research. In this process, the microbes break down organic matter like biomass or wastewater to produce hydrogen. In photolytic biological systems, microorganisms such as green microalgae or cyanobacteria use sunlight to split water into oxygen and hydrogen ions.

HYDROGEN COLOUR CODES :-

Hydrogen itself is a colorless gas. But depending on the type of production used, different colours are assigned to the hydrogen. There are around nine color codes to identify hydrogen including Green, Yellow, White, Black, Brown, Pink, Turquoise, Grey, and Blue hydrogen. But there is no universal naming convention and these colour definitions may change over time, and even between countries.

Grey hydrogen is made from fossil fuels using steam reformation. Blue hydrogen also uses fossil fuels but captures and stores the CO2. Green hydrogen produced by water electrolysis running off renewable energy. Black and Brown hydrogen produced by using black coal or lignite. Pink hydrogen is produced through electrolysis powered by nuclear energy. Purple hydrogen is made though using nuclear power and heat through combined chemo thermal electrolysis splitting of water. Turquoise hydrogen is produced using a process called methane pyrolysis. Yellow hydrogen is made through electrolysis using solar power. White hydrogen is a naturally occurring geological hydrogen found in underground deposits and created through fracking. Red hydrogen is produced through the high-temperature catalytic splitting of water using nuclear power thermal.

WHY IS HYDROGEN THE FUTURE FUEL OF CHOICE :-

Hydrogen can help tackle various critical energy challenges. It offers ways to decarbonise a range of sectors including transport, chemicals, and energy. It can also help improve air quality and strengthen energy security. Unlike fossil fuels, when hydrogen is burned, it generates only water as a byproduct, meaning no harmful greenhouse gas emissions. For this reason, it is an attractive fuel for the future. Hydrogen is one of the leading options for storing energy from renewables and looks promising to be a lowest-cost option for storing electricity over days, weeks or even months. Hydrogen and hydrogen-based fuels can transport energy from renewables over long distances from regions with abundant solar and wind resources, such as Australia or Latin America, to energy-hungry cities thousands of kilometres away. It can be transported as a gas by pipelines or in liquid form by ships, much like liquefied natural gas. These qualities make it an attractive fuel option for transportation and electricity generation applications.

APPLICATION :-

Hydrogen has a long history of being utilized in a wide variety of industries. Thanks to the development of the hydrogen industry in the 20th century, utilizing hydrogen in industrial practices is fairly widespread. Hydrogen can be used across multiple sectors to enable zero or near-zero emissions. Emerging hydrogen markets include data centers, ports, steel manufacturing, and medium- and heavy-duty trucks. Majority of hydrogen today is used as component or catalyst in fields like oil refining, ammonia production, and methanol production. However, hydrogen is increasingly being used in industries like steelmaking. Another potential new use is making concrete, which is a very carbon energy intensive process.

1. Ammonia Production

Currently the ammonia industry is responsible for 1.8% of total carbon dioxide emissions, so there’s significant opportunity to reduce carbon emissions across the world. Hydrogen is essential to the modern ammonia industry. In Haber-Bosch process, hydrogen and nitrogen combines to produce ammonia. Ammonia is commonly used as a critical component of fertilizers and as a result more than half of the world’s hydrogen production goes towards ammonia production. Ammonia production is expected to expand by 40% over the next 30 years, and hydrogen will be a critical part of that expansion. Ammonia also has potential as a storage medium for hydrogen, as it’s more easily transported than liquid or gas-based hydrogen.

2. Transport

Hydrogen can be used as fuel for fuel cells which used to run a variety of transport applications, from automobiles to buses, ships, trains and aircraft. Fuel cells utilize hydrogen to produce electricity onboard the vehicle through a chemical process, without combustion. Different automotive companies plan to produce their own FCEVs in the next couple of years. These vehicles are capable of traveling 300-400 miles on a tank of hydrogen and can be refuel in three-five minutes. Fuel cell trains are now operational in Germany. Deployments of fuel cell trains are scheduled for Japan and South Korea in the future. Shipping and aviation have limited low-carbon fuel options available and represent an opportunity for hydrogen-based fuels.

Marine Transportation

Marine vessels of varying sizes are currently testing fuel cells in new capacities on the water. Vessels from large to small are looking to fuel cells to meet emissions targets. Larger fuel cell models are being prototypes and examined for container shipping vessels. Fuel cells are also used in submarines, which allows submarines to remain submerged for weeks, while also improving silent running operations.

Aerial Vehicles

Aerospace firm Airbus believes hydrogen holds more promise for decarbonising planes than batteries because of the energy it can store by weight. By modifying their existing internal combustion engines, they say they could use hydrogen to fuel their planes. Fuel cells have also been used in manned aerial vehicles for providing auxiliary power on aircraft for applications such as starting the engines and powering on-board electrics. These provide the drones with longer flight times and quick refueling.

The National Aeronautics and Space Administration (NASA) began using liquid hydrogen in the 1950s as a rocket fuel, and NASA was one of the first to use hydrogen fuel cells to power the electrical systems on spacecraft.

3. Steelmaking

Steelmaking requires a high level of heat which typically utilizes coal for both high temperatures and chemical reactions in the process. Hydrogen can be used as a substitute in this process for both the required heat and the chemical reactions. Use of hydrogen will reduce emissions, as steel is one of the fundamental building blocks of modern buildings and industrial processes.

4. Oil Refining

Oil refining is also heavily dependent on hydrogen for transforming crude oil into more useful fuels. Crude oil is introduced into refining facilities, and hydrogen is typically added to the mix. Refining oil requires removing sulfur in the oil until it reaches acceptable levels for the desired fuel type. Hydrogen bonds to sulfur, and creates hydrogen sulfide, which can be extracted from the fuel further along in the refining process.

5. Power

Hydrogen fuel cells produce electricity by combining hydrogen and oxygen atoms. Many different types of fuel cells are available for a wide range of applications. Fuel cells act as power sources for a variety of commercial, industrial and residential applications. These range from homes to spacecraft and research stations. In power generation, hydrogen is one of the leading options for storing renewable energy. Small fuel cells can power laptop computers, electronic appliances and cell phones. Hydrogen and ammonia can be used in gas turbines to increase power system flexibility. Large fuel cells can supply electricity to electric power grids and supply backup or emergency power in buildings. Ammonia could also be used in coal-fired power plants to reduce emission.

6. Concrete Production

Use of hydrogen in concrete production is in experimental testing stage. Hydrogen can’t be directly substituted as an ingredient or reactant in currently utilized cement production methods.

7. Methanol Production

Hydrogen is utilized in methanol production, where hydrogen interacts with carbon monoxide in order to produce the chemical feedstock. Methanol is another resource that is essential for many chemical products. Methanol is a viable alternative fuel for vehicles and machines, and using it can lead to higher fuel efficiency and lower emissions, in addition to the significant chemical uses.