Technologies

  • Polyolefins Pyrolysis

    Polymers Processed

    • Clean LDPE
    • HDPE
    • PP

    Pyrolysis is a thermochemical conversion process conducted in the absence of oxygen that can be considered a ‘feedstock recycling’ process and that can be employed for the production of liquid transport fuel intermediaries or finished fuel products from plastic waste.
    The required feedstock pretreatment lies somewhere between that for mechanical recycling (intensive) and incineration (non- intensive). The liquid energy-carrying medium/output that is produced is easy to store and can be used on demand, and has a higher economic value than electricity produced via energy recovery from waste (waste-to-energy processes). Furthermore, pyrolysis can be employed alongside mechanical recycling and incineration in a cascaded waste management infrastructure, so it should be viewed as a component of a waste management system rather than a competing technology. Pyrolysis is a versatile process that is suitable for both large and small-scale production of several products. For example, pyrolysis of waste polyolefin plastics under different conditions can yield hydrocarbon waxes and oils, BTX aromatics, and olefin gases (ethene, propene, butadiene) (E. Butler, G. Devlin, K. McDonnel, 2011). 

    Process Steps

    1- Pretreatment: clean and shred
    2- Heating under oxygenless 
       conditions
    3- Clean vapors/gases and 
        condense liquid product
    4- Char from biomass
       contaminants as waste product

    Market Readiness Level

    Commercial

    Commercial

  • Pyrolysis (Waste tyres specific)

    The pyrolysis method for scrap tires recycling involves heating whole or halved or shredded tires (to temperatures >400°C ) in a reactor containing an oxygen free atmosphere and a heat source. In the reactor, the rubber is softened after which the rubber polymers disintegrate into smaller molecules which eventually vaporize and exit from the reactor. These vapors can be burned directly to produce power or condensed into an oily type liquid, called pyrolysis oil. Some molecules are too small to condense and remain as a gas which can be burned as fuel. The minerals that were part of the tire, about 40% by weight, are removed as a solid (Zafar, 2020).Pyrolytic oils from waste tires have been burned successfully in test furnaces and diesel engines. Pyrolysis oils can also yield useful chemicals for the petrochemical industry, including light olefins and aromatics. Solid-phase pyrolysis char can be used to create carbon black or activated carbon for pollutant removal. Gases produced, including hydrogen and various hydrocarbons, can be used as a fuel for the pyrolysis process (Ali Alsaleh, Melanie L. Sattler, 2014).

    Process Steps

    1- Pretreatment: remove metal, clean and shred
    2- Heating under oxygenless conditions
    3- Clean vapors/gases and condense liquid product and yield carbon product
    4- Char removal 

    Market Readiness Level

    Commercial

    Commercial

  • Hydropyrolysis

    Polymers Processed

    • PET
    • LDPE
    • HDPE
    • PP

    Hydropyrolysis is the the thermal decomposition which takes place when organic compounds are heated to high temperatures in the presence of hydrogen. Biomass is converted in a catalytic fluidized bed reactor at temperatures of 350–480ºC in a nearly pure hydrogen atmosphere at 20–35 bar. Catalytic hydropyrolysis removes oxygen from the liquid product, while it does not affect char yield and composition. The outlet stream goes into the hydroconversion reactor operating at same pressure and temperature for the stabilization of the liquid product and further reduction of oxygen content. The oxygen in biomass leaves as water mixed with the liquid product and also as CO and CO2 in the off-gas. The off-gas stream is cleaned and reformed for the production of hydrogen for the hydropyrolysis reactor (Pedro Haro et al., 2014) .

    Process Steps

    1- Pretreatment: clean and shred
    2- Heating under oxygenless conditions
    3- Clean vapors/gases and condense liquid product
    4- Pyrolysis oil is hydro-treated in a second step using an external hydrogen source
    5- Char from biomass as waste product

    Market Readiness Level

    Market-ready within 1-2 year(s)

    Market-ready within 1-2 year(s)

  • Solvent-based technologies

    Polymers Processed

    • LDPE
    • HDPE
    • PP

    The generic framework of plastic recycling by solvent extraction includes the removal of impurities, dissolution (homogeneous or heterogeneous dissolution), and reprecipitation or devolatilization. Specifically, the polymer(s) is dissolved in the solvent(s), and then each polymer is selectively crystallized. Ideally, when a solvent can dissolve either the target polymer or all the other polymers except the target one, it can be used to for selective dissolution. Many factors affect polymer dissolution, such as molecular weight, composition, structure of the polymer and composition and size of the solvent.Despite the environmentally friendly properties including energy saving and less CO2 emission of the current solvent extraction of waste plastics technique, it still faces difficulties and challenges, which hinder its development to some extent. Generally, waste plastics are mixed polymers. Therefore, the primary challenge is the separation and recycling of waste components one by one. Existence of solvents and impurities in the recovered products results in the degeneration of material properties compared with those of virgin materials. Further, atmospheric or vacuum distillation also leads to the thermal degradation of polymer chains and worse plastic quality; therefore, the development of proper solvent removal and purifying techniques (e.g., SFE) is very crucial (Yi-Bo Zhao, Xu-Dong Lv, Hong-Gang Ni, 2018).

    Process Steps

    1- Pretreatment: remove excessive contaminants and shred
    2- Dissolution in an solvent under pressure and mild temperatures
    3- Purify the dissolved polymer
    4- Precipitate to (near) virgin polymer
    5- Dry and compound to ready to use recyclate

    Market Readiness Level

    Market-ready within 1 year

    Market-ready within 1 year

  • Gasification

    Polymers Processed

    • PET
    • LDPE
    • HDPE
    • PP
    • Other

    In gasification, plastic waste is reacted with gasifying agent (e.g., steam, oxygen and air) at high temperature around 500–1300 °C, which can produce syngas as a final product. Gasification technology potentially offers feedstock flexibility and customization for generating a range of desirable products. Synthesis gas is further processed into electricity, ethanol, diesel, or other chemicals. In the gasifier, the feedstock is converted through several sequential processes. First, the feedstock is homogenized into smaller particles then inserted into the gasifier, followed by a controlled amount of air or oxygen (and steam for some gasifiers). Feedstock passes through several temperature zones where a sequence of reactions occurs before the syngas produced is removed from the chamber. Solid residue is removed from the bottom of the reaction chamber (Gershman, Brickner & Bratton, Inc., 2013).

    Process Steps

    1- Pretreatment: clean and shred
    2- Heating to high temperatures under oxygenless conditions
    3- Clean gases
    4- Recover solid inorganic contaminants

    Market Readiness Level

    Commercial

    Commercial

  • Mechanical recycling

    Polymers Processed

    • PET
    • LDPE
    • HDPE
    • Other

    Mechanical recycling of plastics refers to processes which involve melting, shredding or granulation of waste plastics. Plastic waste when shredded, can be incorporated into cementitious composites as fibers. Similar to the use of plastic waste as aggregate in cementitious composites, it can also be incorporated into asphalt mixtures and can be used for construction applications as fillers, bricks and walls (P.O. Awoyera, A. Adesina, 2020)

    Process Steps

    1- PET bottles (large and small)
    2- PE/PP bottles to recyclate
    3- Mix to DKR350 to structural materials
    4- Mix to RDF/SRF for energy or aggregates/cement

    Market Readiness Level

    Commercial

    Commercial

  • Hydrocracking

    Hydrocracking is a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The deoxygenation of biomass in the mixed waste streams is required to remove acidity and reach sufficient caloric values. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene (LDPE – HDPE), polypropylene (PP), polystyrene (PS), everyday polyethylene bottles and bags (PET), and composite plastics to desirable fuels and light lubricants (Sibao Liu et al., 2021). 

    Process Steps

    1- Pretreatment: remove metal and shred
    2- Heating under oxygenless conditions, deoxygenise biomass
    3- Char is processed to syngas for biomass deoxygenisation
    4- Clean vapors/gases and condense liquid product


    Market Readiness Level

    Market-ready within 1-2 year(s)

    Market-ready within 1-2 year(s)

  • Waste-to-energy (incineration)

    Direct combustion is the oldest technology for biomass conversion, especially for generating heat and steam. It burns biomass and mixed waste in the presence of oxygen. A biomass combustion facility can produce steam, electricity, or both (combined heat and power [CHP]) through direct firing. The biomass fuel is burned in a boiler to produce high-pressure steam that flows through a series of turbine blades causing the turbine to rotate. The turbine is connected to an electric generator that produces electricity. The steam can also be used in district heating and cooling systems. CHP involves the simultaneous production of heat and electricity. Heat is a by-product of electricity generation; thus, all power plants produce heat but usually it is released to the atmosphere through cooling towers or discharged into bodies of water nearby. In the CHP process, the waste heat is recovered for use in district heating. Co-generation converts about 85% of biomass’ potential energy into useful energy. 

    Process Steps

    Market Readiness Level

    Commercial

    Commercial