Metals Tech

A staggering 30,000 tonnes – that’s the amount of waste Malaysians produce on average daily. This figure was disclosed at the National Waste Management Conference 2018 in July. Worse, only 5% of the total waste is recycled.

That means 10.4 mil tonnes of waste makes its way to landfills across the country a year. Selangor alone contributes 7,000 tonnes daily to these saturated disposal areas, which are quickly piling up as sources of land and air pollution.

Enter the proposal for a Waste-To-Energy (WTE) treatment system by Worldwide Holdings Berhad, a subsidiary of the Selangor government. For this RM500 mil project, Worldwide Holdings is partnering with Western Power Clean Energy Sdn Bhd, a subsidiary of China Western Power Industrial Co.

A joint development agreement was signed on Dec 10 for a WTE facility to be built adjacent to the Jeram sanitary landfill in Kapar, Selangor.

Operational by 2022

“The Waste-To-Energy concept is a waste management technology that is able to convert solid waste into energy in the form of electrical power,” explained Worldwide Group CEO Datin Paduka Norazlina Zakaria.

There are two phases to the project, with an estimated total cost of RM1bil. The first phase with Western Power Clean Energy is expected to be operational by 2022.

“The first phase will have waste capacity of ` per day, which will produce between 20MW to 25MW of green energy, enough to power 25,000 households within the vicinity of the plant,” she said.

According to Worldwide Holdings COO (environment) Zamri Abdul Rahman, the amount of waste in Selangor increases at a higher yearly rate of 4-5% compared to a 2.5% national increase. He pegs this on urbanisation and population hikes.

“About 20ha of land is used up as landfill in a year,” he said, adding that Worldwide Holdings embarked on plans for the development to save land consumption in Selangor.

Feasibility studies comparing landfills and WTE were done, with results showing that WTEs have a longer lifespan than landfills. “95% of WTE in the world uses the type of technology we are planning to use, which complies with EU standards of regulation,” he said.

Worldwide Holdings has yet to decide if it will continue with the second phase, set to be completed by 2024, with Western Power Clean Energy.

How it works

Four major components form the WTE’s functions. It works as an indoor storage facility for solid waste, enclosed incinerator, steam-powered energy generator and a gas filtration system. Dealing specifically with municipal solid waste or domestic rubbish, the waste will be deposited in a lined bunker.

As domestic waste is high in moisture content, it will be stored from three to seven days and rotated repeatedly to ensure it is evenly scattered, as microorganisms facilitate the fermentation of organic waste so it can be burned easily.

Leachate from moisture produced by the stored waste will be filtered out to the Jeram sanitary landfill’s leachate treatment plant. Waste will then be carried to the negative pressure incinerator using a bucket crane.

“Negative pressure means instead of air going out, air from the bunker where we store waste will be pumped into the burner and used for combustion to reduce the discharge of bad odours,” said Zairi, stressing that no air will be released from the incinerator during the combustion process.

The burner reaches high temperatures of more than 850°C to incinerate the waste entirely. Meanwhile, water is heated using the high temperatures of the incinerator to produce steam, which is transferred to steam turbines that generate thermal energy.

Ashes to ashes

“Two types of ashes form during the burning process. The first is bottom ash, which is non-toxic ash usually created by wood and such materials. The harmless bottom ash will be sent to the landfill. Some countries use bottom ash for road construction or making low quality bricks, a possibility we will look into.

“The harder part to treat is fly ash. It contains hazardous materials and particles such as sulphur dioxide and nitrogen oxide. We’ll use activated carbon and slake lime to neutralise these acidic components,” said Zamri.

The process involves a scrubbing system and burning at the highest temperature, so that all toxins and pollutants are destroyed. “Like other parts of the world, we will neutralise the fly ash, then encapsulate it in cement and carry out leaching tests before it is deposited in the landfill,” he said.

Perhaps the most important step is how gas from the combustion unit is treated.

“There is the matter of the toxic fumes dioxin and furan, normally associated with the burning of plastic. These will be taken care of using an activated carbon injection system into the gas before it enters a bag filter, which captures the dioxin, furan and mercury,” he said.

Zamri said Worldwide Holdings will secure skills-based training through their partnership with Western Power Clean Energy. Essentially the transfer of technology and knowledge will provide Worldwide Holdings with the tools to carry out their duties consistently.

Worldwide Holdings has assured the state government and Department of Environment (DoE) that it will have an online display for the public to monitor emission levels in real-time and ensure that the operator meets the standards set.

The big picture

The WTE project is part of a broader and more complete approach, namely Worldwide Holdings’ Integrated Solid Waste Management Centre in Jeram. The centre is touted as a multifaceted approach that includes everything from an anaerobic digester to a research and development centre.

Consistent with the holistic plan, Zamri said waste separation has a key function as the WTE plant works in tandem with the centre.

Non-combustible material such as metal and concrete recovered from the incinerator will be sent to the centre’s material recovery facility for construction and demolition waste, while organic waste from restaurants and hotels will be directed to the centre’s composting plant.

Despite technological advancement, Zamri said that old-fashioned recycling and waste separation is still a necessary practice, with the public playing a vital role.

Once the first and second phases are up and running, the centre is expected to generate 60MW of electricity daily, which can power up to 60,000 households a day.

The Integrated Solid Waste Management Centre now handles waste from six municipalities in central areas of Selangor. Zamri said future plans would involve setting up at least two more such centres, believing that three WTE facilities would be required to sufficiently cope with Selangor’s waste.

“We are planning a centre at our other landfill in Tanjung Dua Belas, Kuala Langat, that caters to waste from the Kuala Langat, Sepang, Kajang and Putrajaya areas. We also proposed another in the north, near the Selayang and Hulu Selangor. Our target is to achieve all this by 2025.

“I think it is doable with the federal government’s manifesto to bring renewable energy from currently around 3% to 20% by year 2025. With these, we hope Selangor will no longer have giant landfills that handle a few thousand tonnes of waste, with all the waste instead going to integrated centres,” said Zamri.

He cited Singapore, which does not have landfills on the island, only WTE plants. Whether WTE is the solution to our problems or just a temporary patch, time can tell.

The only certainty is a need for change and the urgency of handling the problem before it gets out of hand. Right now, a holistic strategy at least sounds like a step in the right direction.

One of highest areas of energy consumption for electric motors is the start-up cycle, as accelerating up to the necessary speed requires a lot of power. Soft starters and VSDs are great ways to reduce and manage energy usage during these periods, by reducing stresses on motors through optimizing start-ups and controlling speeds.

While both technologies can reduce consumption, each is better suited to specific areas. So, which technology is best?

Soft Starters

Soft starters are solid-state devices used to limit the amount of current that can inrush into a motor. The device then slowly lets in increasing amounts of current, softly ramping up the speed of the drive, allowing for a gradual start. This steady approach to power protects the motor from torque spikes and sudden tension, reducing wear and tear of the system.

Many conveyor belts use soft starters to steadily adjust torque to the necessary level. Without this control, sudden tensions could deteriorate the belt and cause it to snap due to mechanical stress. Naturally, this unexpected failure could lead to delays in production.

As the name implies, soft starters only affect the start-up and stopping processes of equipment. While managing this process does improve the energy consumption typically associated with powering up machinery, it does not help control energy consumption during operations.

Soft starters are not expensive devices, and their easy implementation enables manufacturers to improve energy efficiency with very little investment. They are less invasive than other options and as they are a solid state—there are no parts to replace should the device require maintenance.

Soft starters are limited in the amount of money and energy they can save, primarily due to the fact they only influence the start-up and stopping processes of machinery. That said, some high-end soft starters can achieve up to 99 percent better energy efficiency, compared to normal start-up periods. To improve efficiency during machinery operations, a VSD could be a better option.

VSDs

Unlike soft starters, VSDs manage energy consumption by controlling the speed of a motor while it is powering a piece of machinery. VSDs work by converting input current into specific frequencies, with each frequency translating to a determined speed. VSDs not only help reduce consumption during start-up, but also give manufacturers total control of engine speed in all phases of the motor.

The control provided by a VSD also allows for higher quality of actuation to be achieved. More precise control can reduce unexpected stress and strains on the system, allowing devices to last longer as cycles have less impact and wear.

Advanced VSDs are beginning to implement machine learning technology—a type of artificial intelligence (AI) that allows them to learn and automatically optimize their cycle. Investing in a VSD of this type can greatly increase potential savings.

So, what’s the catch?

Original equipment manufacturers (OEMs) have worked hard to reduce the size and price of VSDs. However, these devices are still significantly larger and more expensive than soft starters. As a result, investing in VSDs is not feasible for all manufacturers. In these instances, a soft starter could be a good place for manufacturers to begin their journey to energy efficiency.

Obsolete Sourcing

Adopting either of these technologies, manufacturers can improve energy efficiency, while also increasing the life cycle of machines through more controlled power management. However, that’s not to say machines—or these devices—won’t fail.

A common reason for VSD failure, for instance, is electro-mechanical wear on capacitors. VSDs rely on these capacitors to provide a smooth power output at varying levels of current. However, electrolytic capacitors have a limited lifespan and can age faster than dry components. This alone can be a cause of VSD failure—putting all that effort to improve energy efficiency to waste.

When failure does happen, there several options for manufacturers. For older or obsolete models of VSDs, it is worth establishing a relationship with a specialist supplier of industrial parts. EU Automation provides a single stop for all obsolete automation parts—including soft starters and VSDs.

Energy efficiency is at the forefront of manufacturers’ priorities. Due to the colossal energy consumption of electric motors, it is vital to install effective cost and energy-saving measures from the beginning of these devices’ operations.

Regardless of whether a manufacturer invests in a soft starter, or the heftier VSD —failure to have either of these technologies in place could be a grave energy efficiency mistake.

Researcher discover a way to use solar energy to desalinate seawater in a sustainable and cheap way.

A sustainable and low-cost solar energy device developed by a team of engineers from the Department of Energy at Politecnico di Torino, has the power to turn seawater into freshwater. This technology could be very promising for people in isolated coastal regions and developing nations that have little drinking water but an abundance of solar energy.

The technology was “inspired by plants.”

In their research, published in the journal Nature Sustainability, the group of engineers explained that the technology that they developed is very simple. Two of the project engineers, Matteo Fasano and Matteo Morciano, explain that the technology is “inspired by plants,” transporting water from roots to leaves via capillarity and transpiration.

The team’s floating solar energy device functions in a similar way by collecting seawater using a porous material. This material is low-cost and replaces the need for expensive and bulky pumps.

The seawater that is collected by the device is heated up by the solar energy. This sustains the separation of salt from evaporating water, a process that can be facilitated by membranes inserted between drinking water and contaminated water, preventing the two from mixing. The researchers note that this process is not unlike some plants that are able to survive in marine environments, such as the mangroves.

The low-cost solar energy device can be easily installed and repaired.

Unlike traditional “active” desalination technology, which requires expensive mechanical or electrical components and specialized technicians to install and maintain them, the prototype technology created by the team at Politecnico di Torino, is based on spontaneous process and does not need ancillary machinery. This makes the device cost-effective as well as easy to install and repair.

“While previous studies focused on how to maximize the solar energy absorption, we have shifted the attention to a more efficient management of the absorbed solar thermal energy. In this way, we have been able to reach record values of productivity: up to 20 litres per day of drinking water per square meter exposed to the sun,” the researcher said of their achievement, reported Tech Xplore.

In addition to this solar energy device having the potential to be beneficial for isolated coastal regions and developing nations, where fresh drinking water is scarce, the researchers also say that their technology could also be a benefit in emergency conditions. For instance, in areas where people are hit by floods or tsunamis and are isolated for days or weeks, without access to electricity or an aqueduct.

solar energy device – drinking water – ocean – water bottlePresently, the researchers are looking for potential industrial partners to make their solar energy device prototype more durable, versatile and scalable.

A business which is aiming to bring a new form of renewable energy to tropical resorts has released images of its first design concepts.

Global OTEC Resources has spent the last year developing the company’s concept for using ocean thermal energy conversion (OTEC) especially for off-grid resorts and islands in the Maldives and Caribbean. The company says it has reached a cost model which is comparable to, if not cheaper than, the cost of running diesel generators.

OTEC is a technology for converting some of the energy that the tropical oceans absorb from the sun, first into electricity and then into fuels. During an average day, the 60 million square kilometers of surface waters of the tropical oceans (located approximately 10 degrees north to 10 degrees south of the equator) absorb one quadrillion megajoules of solar energy-equivalent to the energy that would be released by the combustion of 170 billion barrels of oil per day. The surface waters are a warm-water reservoir 35 to 100 meters deep that is maintained night and day at a temperature of 25 to 28°C.

Below about 800 meters, an enormous source of ice-cold water, which is fed by currents flowing along the ocean bottom from the northern and southern polar regions, is maintained at about 4°C. OTEC uses this temperature difference to generate electricity. Warm water is drawn from the surface layer into a heat exchanger to vaporize a working fluid with a boiling point of about -30°C. The vapor drives a turbine attached to an electric generator. Exhaust vapor from the turbine is subsequently condensed in a second heat exchanger, which is cooled by water pumped from the cold water source below. The condensed vapor is then returned to the boiler to complete a cycle that will generate electricity 24 hours a day throughout the year.

Global OTEC Resource’s concept will deliver a net capacity of 1MW of electricity to its customers across the tropics, which is enough to fully power most small-to-midsized resorts or islands. The images show an OTEC plant housed on a floating barge which incorporates a deep cold-water pipe into its hull through a weather-vaning turret mooring system. The cold-water pipe returns seawater from a depth of 1,000 meters, achieving the temperature difference with the warm surface water of 20°C. Ammonia is repeatedly evaporated and condensed to power a turbine and produce electricity.

The company decided to focus its design on the needs of Small Island Developing States after learning that many small islands consume over 10,000 liters of diesel a day. Managing Director Dan Grech says: “Many meetings with both private and public sector representatives in our target markets have indicated that currently, renewables aren’t presenting a viable proposition for islands to cut their dependence on fossil fuels. Thousands of islands lack the space for large solar and battery installations to provide their basic daily electricity loads and feel stuck with diesel generators despite the threat climate change presents to their livelihoods.

“Our next stage is to advance the detail of this design to be ready for fabrication. Our first ocean thermal energy systems will come online in less than two years.”

The first system is expected to be installed in the Maldives, and the company has received positive feedback elsewhere. Tamara Ebanks, Acting Chief Officer of the Ministry of Commerce, Planning and Infrastructure at the Cayman Islands Government, says: “We believe Global OTEC Resources works are aligned with our goals of becoming a sustainable community and simultaneously achieving the United Nations Sustainable Development Goals of Affordable and Clean Energy and the Paris Agreement Targets.”

Global OTEC Resources received a £140,000 ($177,000) grant from Marine-I, an E.U.-funded program designed to promote innovation in marine technology in Cornwall in the U.K.

Researchers at Monash University are now one step closer to providing a solution to minimising the energy wasted by modern telecommunications and computing – simply by the flick of a switch.

Professor Michael Fuhrer, Dr Mark Edmonds and James Collins from the School of Physics and Astronomy at Monash University have, for the first time, successfully ‘switched’ a topological insulator off and on via application of an electrical field.

This announcement is a major advancement towards the creation of a functioning topological transistor – a transistor that would burn much less energy than conventional electronics.

“Ultra-low energy electronics, such as topological transistors, would allow computing to continue to grow without being limited by available energy. This becomes extremely important as we near the end of achievable improvements in traditional, silicon-based electronics,” said Professor Fuhrer.

“Information and communications technology already consumes 8% of global electricity; a figure that is doubling every decade. To solve this problem, we need to develop a new type of transistor that burns less energy when it switches.

“This discovery makes an important contribution in the direction of topological transistors that could transform the world of computation.”

A significant proportion of the growing amount of energy used in information and communications technology is caused by transistor ‘switching’. Each time a transistor switches, a tiny amount of energy is burnt.

“And with billions of transistors in each electronic device, switching billions of times each second, the amount of wasted energy adds up,” explained study co-author James Collins, a Monash University PhD student.

Topological insulators are novel materials that behave as electrical insulators in their interior, but can carry a current along their edges.

Unlike conventional electrical conductors, such topological edge paths can carry electrical current with near-zero dissipation of energy,” said lead author Dr Mark Edmonds..

In order to be viable to the current silicon-based technology, topological transistors must operate at room temperature, without the need for expensive supercooling, and must ‘switch’ between conducting and non-conducting at a rapid rate through an electric pulse.

“While switchable topological insulators have been proposed in theory, this is the first time that experiment has proved that a material can switch at room temperature, which is crucial for any viable replacement technology,” Dr Edmonds said.

The research was conducted through FLEET (The Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technology) – a collaboration of more than 100 researchers at seven Australian universities and 13 Australian and international science organisations.

Nanosized cages may play a big role in reducing energy consumption in science and industry, and machine-learning research at Oregon State University aims to accelerate the deployment of these remarkable molecules.

The porous organic cage molecules being studied at OSU are able to selectively capture gas molecules, potentially enabling huge energy savings in the myriad gas separations conducted in the chemical sector.

“These porous molecular solids are like sponges that soak up gases discriminately,” said Cory Simon, assistant professor of chemical engineering and corresponding author of a study published in ACS Central Science.

Together, the separation and purification of chemical mixtures is responsible for more than 10 percent of the world’s energy consumption.

Porous cage molecules have nanosized cavities intrinsic to their structure, and gas molecules are attracted to and trapped within these cavities via adsorption.

“But each cage adsorbs certain gases more readily than others, and this property potentially makes the cages useful for separating gas mixtures more energy-efficiently,” Simon said.

However, there are thousands of these cage molecules that could be synthesized — to make even one of them and test its properties takes months in the lab — and hundreds of different chemical separations are required in industry; hence the need for a computational approach to sort through the possibilities and find the best molecule for the job at hand.

Simon exploited the idea that the shape of any given cavity is responsible for which gas molecules it most readily attracts.

Simon and students Arni Sturluson, Melanie Huynh and Arthur York employed an “unsupervised” machine-learning method to categorize and group together cage molecules based on their cavity shapes and, thus, adsorption properties.

Unsupervised means the computer did the learning about shape/property relationships on its own; it wasn’t given any labels to instruct it.

“Just show the data to the algorithm, and it automatically finds patterns — structure — in the data,” Simon said.

The researchers used a training dataset of 74 experimentally synthesized porous organic cage molecules that were each computationally scanned, resulting in a 3D “porosity” image of each similar to an image generated by a CT scan.

“On the basis of these 3D images, we took inspiration from a facial recognition algorithm, eigenfaces, to group together cages with similarly shaped cavities,” he said. “Using the singular value decomposition, we encoded the 3D images of the cages into lower-dimensional vectors.”

Simon explains the process using the analogy of people’s faces.

“Imagine you were forced to map everyone’s face onto a point in a two-dimensional scatter plot while preserving as much information as you can about the faces,” he said. “So each face is described by just two numbers, and similar-looking faces are grouped close by in the scatter plot. Essentially, the singular value decomposition performed this encoding, but for porous cage molecules.”

The research demonstrated that the learned encoding captures the salient features of the cavities of porous cages and can predict properties of the cages that relate to cavity shape.

“Our methods could be applied to learn latent representations of cavities within other classes of porous materials and of shapes of molecules in general,” Simon said.