The Power of Reversible Hydrogen Fuel Cells: Separating Hydrogen and Oxygen from Water

Introduction:

The quest for clean and sustainable energy sources has led to significant advancements in the field of hydrogen fuel cells. One of the key challenges in harnessing hydrogen as an energy carrier is the separation of hydrogen and oxygen gases from water. In recent years, reversible hydrogen fuel cells have emerged as a promising solution for this task. In this article, we will explore the workings of reversible hydrogen fuel cells and their role in efficiently extracting hydrogen and oxygen from water.

 

Understanding Reversible Hydrogen Fuel Cells:

 

Reversible hydrogen fuel cells, also known as reversible proton exchange membrane fuel cells (PEMFCs), are a variant of traditional PEMFCs. While conventional PEMFCs generate electricity from hydrogen gas, reversible fuel cells can operate in reverse mode, enabling the production of hydrogen and oxygen gases from water.

 

Mechanism of Action:

 

Reversible hydrogen fuel cells operate through a series of electrochemical reactions that take place within the cell. Let's dive into the detailed process:

1. Electrolysis Mode:

In the electrolysis mode, an external electrical current is supplied to the reversible fuel cell, initiating the splitting of water molecules into hydrogen and oxygen gases.

• At the anode:

2H2O (liquid) → 4H+ (protons) + 4e- (electrons) + O2 (oxygen gas)

• At the cathode:

4H+ (protons) + 4e- (electrons) → 2H2 (hydrogen gas)

 

When the electrical current is applied, water molecules at the anode are oxidized, releasing protons (H+) and electrons (e-). The protons migrate through a proton exchange membrane to the cathode, while the electrons flow through an external circuit. At the cathode, the protons and electrons combine, resulting in the production of hydrogen gas.

2. Fuel Cell Mode:

 

During the fuel cell mode, hydrogen gas and oxygen gas are supplied to the reversible fuel cell, which then generates electrical energy through the reverse reaction.

• At the anode:

2H2 (hydrogen gas) → 4H+ (protons) + 4e- (electrons)

• At the cathode:

O2 (oxygen gas) + 4H+ (protons) + 4e- (electrons) → 2H2O (liquid)

 

In this mode, hydrogen gas is oxidized at the anode, releasing protons and electrons. The protons migrate through the proton exchange membrane to the cathode, while the electrons flow through an external circuit, generating electrical power. At the cathode, oxygen gas combines with protons and electrons to form water.

Note: This animation from FREUDENBERG Youtube Channel will remove your confusion about Electrons migration and producing Electricity.

Efficiency and Advantages:

 

Reversible hydrogen fuel cells offer several advantages over traditional electrolysis methods for hydrogen production. Firstly, they are highly efficient, allowing for the conversion of electrical energy into chemical energy (hydrogen) with minimal energy loss. Secondly, these fuel cells can be integrated with renewable energy sources, such as solar or wind power, enabling sustainable hydrogen production. Furthermore, reversible fuel cells provide the flexibility to switch between electrolysis and fuel cell modes, making them versatile for various applications.

 

Conclusion:

 

Reversible hydrogen fuel cells represent a significant leap forward in the field of hydrogen separation from water. By leveraging the principles of electrochemistry, these innovative cells enable the efficient extraction of hydrogen and oxygen gases. With their high efficiency and adaptability, reversible fuel cells hold great potential for a sustainable and clean energy future, providing an eco-friendly alternative to traditional fossil fuel-based systems.

 

Once again, many thanks from ELBCAMPUS administration for providing us such an interesting subject with great practical methods.

 

Naeem Nekmal

Hamburg, Deutschland

June, 2023

How Do Engineers Build Structures Underwater?

Building structures underwater requires some interesting engineering. 

Have you ever looked at a large bridge or other structure whose foundation was rooted underwater and wondered how engineers ever went about constructing it or will ever fix it? When construction needs to take place somewhere that is submerged underwater, engineers use a series of large driven piles into the waterbed called cofferdams to create a dry workplace.

The way cofferdams are built: 

In terms of geotechnical engineering, the process isn't as simple as just pushing walls into the ground, engineers have to carefully design the structure to not flood and keep the workers inside safe from collapse. Most traditionally you would see cofferdams in the construction process of support piers for bridges, but they can be used in a wide variety of aqueous engineering

The piles of a cofferdam are driven into the earth in whatever formation necessary to a specific depth. When water is on one side of a wall and water is pumped out of the other side of the wall, this creates a hydraulically unstable system which can cause water to seep up through the ground.

Without getting too complex into the geotechnical engineering of this hydraulic phenomenon, there is a depth at which a wall can be driven into the ground that will keep water from seeping to the other side of the wall – typically defined by soil type and water table. The piles used in cofferdams are usually driven into the surface at a minimum of this calculated height in order to keep water out.

Removing the water from the structure:

Once the entire cofferdam is in place, pumps are used to extract the water interior to the dam structure, ultimately creating a dry workspace. Sometimes, getting the piles that make up the cofferdam to a necessary depth on the lake/ocean/river floor is simply too expensive or impractical. In cases like this, a series of pumps are set in place to constantly pump out excess water as it seeps into the cofferdam structure.

These structures are used very commonly when constructing dams, piers for bridges or other forms of aquatic engineering. While it may seem that having such a large work area under the surrounding water level may be dangerous, and it is, it's not as dangerous as you may think. Work inside of cofferdams is usually only allowed under the most pristine conditions when the water is generally static. In these states, failure modes of the pile dam are slow and predictable in nature. To help fight against these slow failures as well, a series of primary or backup pumps can kick into overdrive to help keep the inside of the cofferdam dry until crews can evacuate.

When ships need to be repaired, engineers will also use cofferdams as a sort of dry-dock to isolate the ship from the water and repair it where it sits. This is typically done on larger ships where it would otherwise be impossible to lift the ship out of the water. So, for example, when a cruise ship is lengthened or expanded, engineers will construct a cofferdam around the ship and pump out the water, allowing for workers to have a dry work area. It is important to note that cofferdams are not cheap, but for the projects where they are used, they are the only construction option.

History of cofferdams:

Cofferdams are rather old when it comes to underwater construction vice that there aren't really any other ways to build underwater. The origins of these structures date back to the Persian Empire where they began as earth cofferdams.

These early structures were made essentially how you might think, with earthen walls being built up, the water being bucketed out, the structure being built, then the earth walls removed. It was rather tedious, dangerous and time-consuming, but it did the trick.

The next innovation in cofferdam engineering was made by the Romans. Roman engineers used woodpiles that they drove into waterbeds to wall off underwater areas. This was particularly an impressive feat considering the function was similar to modern steel cofferdams, yet the Romans were able to accomplish it with wooden supports.

In what seems like a step back in the engineering of cofferdams, the next innovation was to move to sandbags, which didn't occur until the late 19th century. During the Napoleonic wars, people began using sandbags to control water. The bags were initially used to protect troops but eventually began being used to control the water by building quick dams. While not the traditional use of cofferdams, these early sandbag dams allowed for troop movements while also offering the added benefit of protection from gunfire.

Steel sheet pile cofferdams:

Finally, after the long history of cofferdams in construction, in the early 1900s, steel cofferdams were first invented by a German engineer. These first steel dams utilized interlocking U shaped steep to control the water flow and are much like what we still see in use today. This was really the final major innovation in the history of Cofferdams as today, we just see minor proprietary changes in the wall interlocking technology.

Top 10 Most Impressive Civil Engineering Projects

By M. Naeem Nekmal

Throughout history, numerous incredible engineering projects have been established and completed. From the earliest annals of history to modern times, there are numerous creations that showcase our ability to realize an incredible constructive vision. While every engineer or anyone who appreciates structures may have their own opinion on what engineering project is most impressive, it can be assumed that these men would be placed at the top:

Great Pyramid of Giza: This incredible creation consisted of two and a third million stone blocks, which required the constant labor of thirty thousand laborers to build.

Great Wall of China: What many people do not know about this enormous five thousand and a half-mile long wall is that the mortar used in its construction is made of rice flour.

Aqueduct of Segovia: These amazing aqueducts are made without the use of mortar, and are so well preserved that it is still in use today.

Brooklyn Bridge: Was the first suspension bridge to use steel in its cables.


Panama Canal: This man-made canal was designed to connect the Atlantic and Pacific oceans to provide trade ships with a passage between North and South America.


Hoover Dam: Named one of the Seven Wonders of the World, the dam generates four billion kilowatt-hours of electricity for use.


Golden Gate Bridge: This historic wonder connects San Francisco to the rest of the bay, and is made up of six hundred thousand rivets.


English Channel Tunnel: A thirty-one-mile long tunnel, the English Channel Tunnel currently contains the longest portion of any tunnel housed under the sea.


Burj Khalifa: Interestingly enough, one of the biggest setbacks to face the construction of the Burj Khalifa, the world’s tallest building, was one hundred and sixty kilometers per hour winds that required special testing to determine the safety of the construction material.


Qingdao Haiwan Bridge: It is currently the longest bridge in the world and was specially designed to withstand earthquakes and typhoons.

The Future of Special Economic Zones in Afghanistan

HOW DOES THE TRUMP ADMINISTRATION’S NEW SOUTH ASIA STRATEGY CHANGE THE PLAN FOR ESTABLISHING SEZS IN AFGHANISTAN?

The concept of special economic zones in Afghanistan is not intentional, rather accidental.  The scheduled withdrawal plan of U.S. and NATO forces in 2014 left a huge amount of infrastructure to Afghan forces. This included $2 billion worth of infrastructure and equipment at eight strategic airfields in the country, equipped with sophisticated machinery and a well-developed infrastructure.

Bastion-Helmand and Bagram-Kabul, in particular, are of considerable importance. Ashraf Ghani, the current president of Afghanistan and a former World Bank employee, proposed creating special economic zones (SEZs) at each airfield. An SEZ is a designated area where investors encounter more liberal investment and trade laws. Ghani’s proposal followed the path of Jordan, Panama, and the Philippines, which did the same with airfields in the past.

In order to efficiently utilize these airfields, President Ghani issued decree #43 in July 2015 for the establishment of the Afghanistan Airfields Economic Development Commission (AAEDC) which will carry through the SEZ plan. The development of SEZs in the country could pave the way to boosting the war-torn economy and decreasing dependency on foreign aid and donors by attracting foreign direct investment (FDI), creating domestic jobs, promoting exports and developing infrastructure.

The concept of SEZs is a groundbreaking initiative of the National Unity Government (NUG), and AAEDC is giving momentum and shaping the idea into practice. AAEDC has been working on several pathways to create the foundation and framework for the transition and development of portions of various NATO/ISAF-built facilities at several airbases in order to take practical steps to convert the airfields into SEZs.

Research by Samuel Hall reflects that Mazar-e-Sharif, Kabul, and Herat are possible options for establishing SEZs. These zones can be further extended to other provinces. The AAEDC in conjunction with its member ministries and the Chief Executive Office made a strategic plan for the upcoming three years to transform the SEZ idea into reality. Subsequent to these objectives, AAEDC intends to establish the first SEZ adjacent to the Kandahar airfield for which the approval of the High Economic Council has already been granted and later will expand the SEZ network to other viable regions within the country.

The Kandahar airfield has a strategic location vis-a-vis the international ports of Chabahar and Gwadar. Kandahar province is rich in agricultural and natural resources with comparative advantages in terms of raw material availability and potential business opportunities in the designated area. Afghanistan’s untapped wealth of minerals, including lithium and copper is estimated to be worth $1 trillion to $3 trillion. Lithium and copper are essential to modern industry.

The Trump administration’s new strategy for Afghanistan seems to be influenced by mining interests, with the administration taking seriously Afghanistan’s mineral resource potential. Global estimates show that world demand for lithium will exceed supply by 2020 and the world will face a shortage of a key metal that is abundant in Afghanistan. Global demand for these precious metals could eventually transform Afghanistan into one of the most important mining centers in the world.

The 16th-century geographic importance of Afghanistan was summarized by Babar, founder of the Mughal dynasty: “In Afghanistan, you can go in a single day to a place where the snow never falls, and in two hours you can also reach a place where the snow never melts.” In the 21st century, the great potential geoeconomic importance of Afghanistan remains robust — a hub of international trade connecting the energy-producing countries of Central Asia with the energy-hungry economies of South Asia. The establishment of SEZs in Afghanistan pairs well with connectivity initiatives in Central and South Asia to bring economic and political stability across the region. Joint-SEZ initiatives could change trade across the region. Such Joint SEZs could bridge the demand and supply gap in Asia, by Asia, through Asia. The Joint SEZ concept also pairs with China’s Belt and Road Initiative (BRI).ADVERTISEMENT

Well-developed infrastructure, resource availability, and location are the key determinants for the success of an SEZ; Afghanistan is blessed inherently with the latter two. Regional economic cooperation organizations like the South Asian Association for Regional Cooperation (SAARC), Economic Cooperation Organization (ECO), Central Asia Regional Economic Cooperation (CAREC), and the Shanghai Cooperation Organization (SCO) can assist in feasibility studies and assessments targeted at the extractive industry of Afghanistan. The government of Afghanistan should prioritize open discussion among the regional countries for joint-SEZ. Establishing SEZs will also impact private sector growth, create opportunities for employment and will give relief to the headache of unemployment in the country.

Although the implementation of the SEZs is a win-win situation, believed to bring economic prosperity, security is the main problem preventing progress beyond financial issues. Taliban and other insurgents continue to seize territory and carry out coordinated attacks in the capital and in major provinces.

The Trump administration’s new South Asia strategy encompasses Pakistan, India, and the Central Asian nations and extends into Southeast Asia, but there is also an emphasis on Afghanistan. It does not involve a withdrawal of U.S. troops from the United States’ longest-running war but instead an increase in troop levels in four garrisons (Kabul, Kandahar, Bagram, and Jalalabad) to halt the deteriorated security situation. As such, the United States is reluctant to hand over its strategic airfields to the Afghan government, which was expected in 2018 as laid out in a previously scheduled transfer plan. NATO allies and global partners like Australia are also supporting the new strategy and have already pledged additional troops and funding increases to Afghanistan. The concept of establishing SEZs in Afghanistan is interlinked with the airfields transfer.

The SEZ idea will be buried under the dust of new boots on the ground in Afghanistan, as the United States is set to send up to 3,000 additional troops. Afghanistan’s meager developmental budget alone cannot answer the question of establishing SEZs, and the idea will likely have to wait for a later time.