Fuels plastics-derived

It has been demonstrated that oil recovered from PVC-containing plastic feedstock can be used as a fuel. Cost is the main obstacle since it requires a large amount of slaked lime to neutralize the HCl gas that is produced by the thermal cracking. Table 15.1 shows the effect that slaked lime has on reducing the chlorine content of fuel oil derived from the pyrolysis of PE (55 wt%), PP (28 wt%) and PS (17 wt%) at a decomposition temperature of 420°C. 

Similar to petroleum-derived cracking the fractions from plastics pyrolysis can contain a significant concentration of unsaturated hydrocarbons (especially a-olefins) [9]. The mono- and diolefin content makes the diesel fuel prone to instability due to polymerization and the formation of deposits (i.e. gums). Since the plastic-derived diesel fuel has an appreciable olefins content it is important to subject it to a hydrogenation step (e.g. hydrogenation over PCI/AI2O3 at 300-320°C and 3 MPa H2) which lowers the bromine number from typical values of 22-28 g Br2/100 g to less than 0.5 g Br2/100 g [9]. 

STORAGE STABILITY OF PLASTIC-DERIVED DIESEL FUEL... 

Diesel fuel made from the thermal cracking of plastics is more susceptible to oxidation and polymerization than refinery-made diesel fuels. This is because plastic-derived diesel fuels generally have terminal unsaturation (i.e. double bonds) at the ends of the diesel chains as a result of the P-scission chain cleavage. Over time free radicals that form in the plastic-derived diesel fuels during storage cause the diesel chains with double bonds (a-olefins) to polymerize resulting in a sludgy sediment also known as gum . 

N. Lingaiah, M. A. Uddin, A. Muto, T. Imai, and Y. Sakata, Removal of organic chlorine compounds by catalytic dehydrochlorination for the refinement of municipal waste plastic derived oil. Fuel 80, 1901 (2001). 

The halogen-free plastic-derived oil obtained dnring the pilot plant studies was tested in diesel power generation engines in a 1 3 mixtnre with commercial fuel oils (kerosene) and the test was snccessfnl. 

N. Lingaiah, Md. Azhar Uddin, A. Muto, K. Murata, and Y. Sakata, Catalytic dehydrochlorination of chloro-organic compounds from PVC containing waste plastics derived fuel oil over FeCVSiOa catalyst, Green Chem., 3, 74-75 (2001). 

Despite the fact that they are chemically identical, it is possible to analytically identify bio-based plastics apart from identical fossil fuel-based plastics. Carbon dioxide in air has two isotopic forms of carbon, CO and CO, in equilibrium with each other, and plastics derived from plant sources will therefore have both these isotopes. Any isotopic carbon in fossil fuel deposits, however, had long decayed over the millions of years since their formation (half-life of C is 5730 years) into C and fossil fuels, and plastics made from them do not have significant levels of Burning a sample of plastic and measuring the ratio in the CO using liquid scintillation counting or isotope-ratio mass spectrometry therefore provide a test as to the origin of the plastic (ASTM D 6866). 

The terms biodegradable plastics and bio-based or bio-derived plastics were already defined in Chapter 4. Plastics can be classified in terms of the source of raw materials into four classes plastics based on fossil-fuel feed stocks, biopolymers made by living organisms, modified biopolymers, and bio-based plastics derived from renewable biomass feedstock. Members of each of these classes can be either inherently biodegradable or recalcitrant when placed in an appropriate biotic environment. BiodegradabiUty is a property or characteristic of plastics and is independent of the feedstock it is based on. This distinction was discussed in detail in Chapter 4 and is further illustrated in Figure 6.11. 

Liquid phase catalytic processing is a promising biorefinery process that produces functionalized hydrocarbons from biomass-derived intermediates (e.g., intermediate hydroxymethylfurfural or HMF). Renewable furan derivatives can be used as substitute building blocks for fossil fuels, plastics, and fine chemicals, ° or to develop biofuels based on C5 and C6 carbohydrates (sugars, hemicellulose, cellulose). Currently, Avantium Chemicals in the Netherlands is developing chemical catalytic routes to generate furanics for renewable polymers, bulk and specialty chemicals, and biofuels. ... 

Natural plastics/bio-plastics or organic plastics are special type of biomaterials, made from renewable biomass sources such as vegetable oil, com starch, pea starch, or microbiota, rather than fossil-fuel plastics which are derived from petroleum. 

Post-consumer materials provide the final category of opportunity fuels. Representative post-consumer materials include tire-derived fuel (TDF), commonly used in cyclone boilers, stoker boilers, and cement kilns. Other post-consumer materials used as opportunity fuels include waste oil and re-refined oil, wastewater treatment gas, landfill gas, paper-derived fuel (PDF), plastics-derived fuel, refuse-derived fuel (RDF), sewage sludge, wastewater treatntent gas, and selected hazardous wastes burned in industrial boilers and kilns. 

Since plastics are generally made from hydrocarbon feedstocks they should be recycled to conserve energy. The most effectives energy conservation is to refabricate plastic items, though this is not always technically feasible. Under circumstances where recycling is not a feasible option the use of plastics in waste-derived fuels may be an acceptable conservation measure. 

From the description above it already can be deduced that this plant can deal with a lot of waste types and hence is rather robust in terms of acceptance criteria. S VZ has experience with treating mixed plastics waste, waste derived fuel (a mixture of plastics, wood and paper), the shredder light fraction of car wrecks, and the plastic fraction from shredded white goods and electronics. SVZ can handle on average 2% chlorine in MPW, with short-term excursions to 6%. The overall chlorine content has to be controlled by a right blend with other waste types. SVZ does not favour a high... 

Coal used in power stations has the potential to be partly replaced by fuels derived from pre-treated plastics and paper waste, reducing both dependency on fossil fuels and reliance on landfill. APME reports on a project in the Netherlands which it co-sponsored to develop a substitute fuel from plastics. The environmental assessment of the project compared the environmental impacts of coal substitution with other plastics recovery methods, including gasification in feedstock recycling and energy recovery from plastics waste in cement kilns. The study also compared coal substitution with the generation of power from burning biomass. 

Combustion of plastics waste with energy recovery is discussed as one approach to the recycling and waste management of waste plastics. Their role in municipal solid waste combustion is examined, and the importance of refuse derived fuel pellets. Facts supporting the importance of waste to energy projects are reported, and details of some projects currently examining MSW combustion with energy recovery are detailed. 

USE OF REFUSE DERIVED FUEL ENHANCED WITH POST-CONSUMER PLASTICS FOR THE PRODUCTION OF ELECTRICAL ENERGY BY THE GASIFICATION PROCESS... 

Results are presented of studies undertaken in Italy by SAFI and Replastic of the gasification of refuse derived fuel enriched with post-consumer plastics for the production of electrical energy and gas for use in cement making. 11 refs. 

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