The push for carbon-neutral fuels and the minimizing of waste has lead to the discovery of some new and emerging forms of recycling for fuels. The new and emerging technologies include carbon capture, the use of trash for heat and fuel, using plastic as fuel, recycling waste fuel, and turning waste food into fuel. A very new and currently being tested source of fuel is CO2 emissions recycling. Each form of recycling is addressed below.
SWEDEN – RECYCLING TRASH FOR HEAT & FUEL
Sweden banned organic and combustible waste in landfills during the years 2002 to 2005. In 1975 the average recycled waste per person was around 40 pounds. In 2016 that number rose to 357 pounds being recycled. During that same time period, an average person produced 430 pounds of trash sent to a landfill, and now only 6.6 pounds are produced. This is very important because organic waste in landfills generates methane which is 72 times more potent as a greenhouse gas than carbon dioxide.
These efforts have reduced landfill usage and the burning of fossil fuels. To handle the amount of organic and combustible trash produced, Sweden has shifted to burning the trash. This switch has lead to the avoidance of emitting 467,000 tons of carbon dioxide in just one year.
The trash-burning operations produce heat, electricity, and methane biogas. The biogas is utilized as a fuel for 200+ city buses, along with garbage trucks, taxes, and private vehicles. A special biogas digester is utilized to create methane that is refined, scrubbed of carbon dioxide, and finally distributed to fuel stations.
Critics are claiming that this type of power plant discourages recycling and waste reduction and detracts investments from renewable energy programs. However, Sweden has increased its recycling efforts along with its wind and solar energy capacities, aiming to have 100 percent renewable energy by 2040. They also have the goal of net zero greenhouse gas emissions by the year 2045.
FOOD WASTE TO ENERGY
Similar to Sweden’s initiatives of burning organic waste, companies around the world are building factories to convert food waste. While the idea of using food for a fuel source such as biofuel or ethanol is decades old, the ability to turn food waste into biogas differs in the process and is still an emerging technology. Food waste is considered an untapped resource and a high potential for generating energy.
The idea is to prevent landfill waste and utilize food waste. It is estimated that one-third of all food produced around the world is discarded uneaten. Seventy percent of the world’s food waste still goes to landfills. There are currently 800 industrial-scale waste to energy plants located in more than 36 countries around the world. One such plant claims to convert 180,000 tons of food waste a year into biogas that can fuel power plants, vehicles, and other types of equipment. Organic waste from slaughterhouses, breweries, farms, and coffee shops have the potential to power hundreds of homes each day. (Source 9)
Efforts are underway to remove carbon dioxide from the atmosphere and then convert it into carbon-neutral fuels. Doing so will stabilize the climate and negate the need to alter energy systems or force people to change their habits.
A Canadian company called Carbon Engineering has already put this technology into place. Carbon Engineering has raised a total of $82.4 million in funding over four rounds from July 2018 with the last round of funding in March 2019. Bill Gates and BHP Billiton Petroleum are the most recent investors in the company and two of the seven total investors.
The technology works by condensing the air in cooling towers with fans. The carbon dioxide is drawn into an alkaline liquid and then separated, frozen, and reheated into a slurry combined with hydrogen to make liquid fuels such as gasoline and jet fuel. Currently, the commercial application of this technology is to create new fuels. Storing the carbon is also possible, but there is no market for this application at the current time.
Carbon Engineering has commercialized two clean energy solutions to produce a net-zero carbon result. These two technologies are Direct Air Capture and Air to Fuels. Direct Air Capture removes carbon dioxide directly from the atmosphere and delivers large-scale negative emissions. With this system, Carbon Engineering can capture one million tons of CO₂ each year which equates to the annual emissions of 250,000 cars. Air to Fuels reduces the carbon footprint in the transportation industry by creating clean synthetic fuels produced from air, water, and renewable power. The fuels produced burn cleaner than fossil fuels and can be produced with 100 times less land than biofuels require.
PLASTIC WASTE INTO FUEL
European countries have strict management strategies, but even so, only 31% of plastic waste is recycled. This has lead to the examination of whether or not different types of plastics can be recycled into fuel. Chemical recycling of plastic can be done by gasification and pyrolysis which yields both energy carriers and feedstocks for fuels.
A synthesis gas can be produced by heating waste plastic with air or steam. This process known as gasification produces products such as diesel and petrol and can also be burned directly to generate electricity. Pyrolysis involves heating waste plastic in the absence of oxygen which yields a mixture of oil that is similar to crude oil. This product can be refined into other transportation fuels. Both processes have lower emissions of sulfur and nitrogen oxides than incineration and provide more flexible ways of storing energy than burning allows.
Gasification of plastic waste requires significant funding and systems which reduces its availability. On the other hand, pyrolysis is modular, requiring little funding in comparison and is easy to roll out. Plants for pyrolysis have already been constructed in Japan, the UK, and the United States. (Source 5)
WASTE FUEL RECYCLING
Waste fuel recycling management programs arise from the International Convention to prevent sea pollution, known as MARPOL 73/78. This international convention applies to 97% of active ships requiring that they properly manage their waste and do not dump it into the sea.
The conventional method of recycling waste fuel is to collect it and burn it off in industrial furnaces. Centrifuges are employed by some processes and consume much power while producing a wet product. Fuels are not recoverable from this method of recycling.
The company Sequoia employs specially designed heat exchanger and recovery systems to treat waste fuel oils. Their method completely evaporates emulsified and free water and recovers diesel from waste fuel oil. Their technology produces a high-value diesel product that meets residual fuel specifications for flash point and water content.
Sertego, another company pioneering the way in waste fuel recycling, developed an innovate set of techniques to treat and recover fuel while minimizing the impact on the environment. They can convert MARPOL waste fuel into motor oil which can be introduced back into the market.
CO2 EMISSIONS RECYCLING
The ability to recycle CO2 emissions is an exciting emerging technology. Researchers from the University of Toronto feel that capturing CO2 can turn it from waste into a valuable energy resource. The idea revolves around the ability to capture the CO2 emitted from power stations and other sources and reduce it into simple hydrocarbon fuels or other small molecules that can then be used as the building blocks for more complex fuels.
Currently, scientists feel that the process is not efficient nor economically feasible. Companies such as Opus-12, Mitsui Chemicals, Carbon Recycling International, Dioxide Materials, and Carbon Electrocatalytic Recycling Toronto are all working to commercially viable solutions.
In addition to the CO2 emission capturing technology, scientists are also experimenting with bio-hybrid approaches and genetically modified bacteria to convert CO2 into more complex chemicals. With the speed of research and advancements in understanding, it is felt that industrial impact could be made within the next five to ten years.