Making wastes-to-hydrogen conversion a reality

AS HYDROGEN continues to fuel Malaysia’s ambitions of being among the world’s leading hydrogen economies by 2050, the idea of producing that resource comes in the form of using Sarawak’s many hydroelectric projects.

However hydrogen, although an abundant element in our world, remains bound to other elements and extracting that has been a major focus for world economies eager to pivot towards cleaner energy sources.

At the current moment, though, the production cost of green hydrogen is higher than fossil fuels, which makes it expensive, especially for developing countries that are rich in oil and gas.

Even building the facility to produce, store and distribute hydrogen will require significant investment.

However, with advances in technology, more ways of extracting hydrogen would inevitably be available.

One of these methods may even help solve the ongoing issue of the world’s ever-increasing accumulation of waste, and that is the extraction of hydrogen from waste products.

Rising challengesWhen it comes to waste accumulation, Malaysia faces a mounting issue: according to an article in The Star early this year, Malaysians dispose about 39,000 tonnes of solid waste each day.

That’s the same as roughly 1.17kg per person, quoting the Solid Waste Management and Public Cleansing Corporation (SWCorp).

SWCorp also mentioned that food makes up the biggest component of domestic waste at 30.6%, followed by plastic (21.9%), paper (15.3%), disposable diapers (8.2%) and hazardous household waste (4.2%).

The United States International Trade Administration also pointed out that Malaysia could potentially run out of land for landfills come 2050.

Greenpeace Malaysia also noted that there have been uncounted illegal dumping grounds for domestic waste and hazardous scheduled waste, like e-waste and chemical wastes.

One solution is to convert waste into energy.

The hydrogen equation

There have been technologies that aim to convert waste into hydrogen; a myriad of methods that a colour spectrum has been used to assign to how clean the gas was produced.

Although initially limited to just three colours—grey (using fossil fuels), brown (like grey but carbon is captured) and green (using renewable sources)—there is now a whole gamut that runs from yellow (using solar) to turquoise (using heat without combustion).

To convert waste into hydrogen, experts can consider several waste sources.

With the discussion of food waste, converting this looks to be the most obvious, as this is a form of organic waste.

Organically produced

But organic waste is more than just food; it also includes municipal solid waste, agricultural residues and other organic materials.

These can be decomposed through anaerobic digestion to produce biogas rich in methane, which then is steamed to produce either grey or blue hydrogen, as the process also disperses a small amount of carbon monoxide and dioxide.

Advancements at the Pacific Northwest National Laboratory in the US in 2021 have shown ways of even producing green hydrogen from methane.

Furthermore, the American Chemical Society published a story on how a chemical engineer at the Council of Scientific and Industrial Research-Indian Institute of Chemical Technology converted food waste from the institute’s cafeteria using microbes that produced a gas rich in hydrogen.

For Malaysia especially, the palm oil industry produces a large amount of waste that includes empty fruit bunches, palm oil mill effluent and palm kernel shells, more of which will be explored further below.

Rehabilitating plastics

In terms of wastes, plastics itself presents quite a conundrum: you can’t live without it and yet, it is one of the world’s major forms of pollution, due to its non-biodegradable nature.

However, plastics can be broken down to yield carbon monoxide, hydrogen and carbon dioxide via a method called gasification, whereby steam or oxygen is heated to about 700°C, without combustion.

This produces a form of grey hydrogen, after which the carbon can be captured and sequestered.

A new method is to run plastics under electricity for a short burst, which heats them up to about 2,800°C, a process that apparently converted up to 93% of the hydrogen atoms present in the polymer into hydrogen gas with a purity of 87%, according to a research at at Rice University in Houston, Texas.

The process produces not only hydrogen but a form of graphene, a strong yet flexible material that is also light and highly resistant that is highly valued by car manufacturers.

Industrial revolution

With regards to wastes running from industrial activities, one could look at Malaysia’s palm oil industry, simply because as one of the world’s largest palm oil producers, the amount of waste it generates has to be addressed.

The Malaysian Investment Development Authority (Mida) reported that over 99% of the emissions from industrial waste water treatment and discharge originate from palm oil mill effluent.

Much of these can be repurposed as raw materials for conversion to energy.

According to the Science, Technology and Innovation Ministry (Mosti), Malaysia produces more than 90 million tonnes of biomass from palm waste that can potentially be processed using pyrolysis to produce turquoise hydrogen, with solid carbon as a byproduct.

The ministry aims to conduct further research with NanoMalaysia Bhd on ways to produce turquoise hydrogen through advanced microwave plasma technology.

The pulp and paper mill industry also represents another opportunity to convert waste to hydrogen.

Scientific research has revealed that hydrogen-methane can be produced from pulp and paper sludge, as well as food waste, using “mesophilic-thermophilic anaerobic co-digestion”.

That basically means the wastes are broken down by bacteria under specific temperature conditions and that releases hydrogen as well as methane.

Furthermore, a byproduct of the pulp and paper industry, called black liquor can be gasified to produce hydrogen-rich syngas.

Another form of waste is wastewater treatment sludge, which can also be processed via anaerobic digestion or pyrolysis to produce hydrogen.

Although most of these methods are still in their nascent stages, some countries have already started, one being TheGreenBillions Ltd in Pune, India and the Project Hyield in Europe.

Malaysia could pave the way for South-East Asia in reforming hydrogen from wastes, as this is potentially a way for the country to increase its hydrogen production while pursuing a circular economy.