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Thermal Depolymerization
Thermal depolymerization (TDP) is the process of converting a polymer into a monomer or a mixture of monomers, by predominantly thermal means. It may be catalyzed or un-catalyzed and is distinct from other forms of depolymerization which may rely on the use of chemicals or biological action. This process is associated with an increase in entropy. For most polymers, thermal depolymerization is chaotic process, giving a mixture of volatile compounds. Materials may be depolymerized in this way during waste management, with the volatile components produced being burnt as a form of synthetic fuel in a waste-to-energy process. For other polymers, thermal depolymerization is an ordered process giving a single product, or limited range of products; these transformations are usually more valuable and form the basis of some plastic recycling technologies. Disordered depolymerization For most polymeric materials, thermal depolymerization proceeds in a disordered manner, with random chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilizer
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods. Historically, fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations, and byproducts of human-nature industries (e.g. fish processing waste, or bloodmeal from animal slaughter). However, starting in the 19th cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquefied Petroleum Gas
Liquefied petroleum gas, also referred to as liquid petroleum gas (LPG or LP gas), is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, Butane, ''n''-butane and isobutane. It can also contain some propylene, butylene, and isobutylene/Isobutylene, isobutene. LPG is used as a fuel gas in HVAC, heating appliances, cooking equipment, and vehicles, and is used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce the damage it causes to the ozone layer. When specifically used as a vehicle fuel, it is often referred to as autogas or just as Autogas#Terminology variations and confusion, gas. Varieties of LPG that are bought and sold include mixes that are mostly propane (), mostly butane (), and, most commonly, mixes including both propane and butane. In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane. In the United States, mainly two grad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocracking
In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon–carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of large hydrocarbons into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking long-chain hydrocarbons into short ones. This process requires high temperatures. More loosely, outside the field of petroleum chemistry, the term "cracking" is used to describe any type of splitting of molecules under the influence of heat, catalysts and solvents, such as in processes of destructive distillation or pyrolysis. Fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Municipal Waste
Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, as in a garbage disposal; the two are sometimes collected separately. In the European Union, the semantic definition is 'mixed municipal waste,' given waste code 20 03 01 in the European Waste Catalog. Although the waste may originate from a number of sources that has nothing to do with a municipality, the traditional role of municipalities in collecting and managing these kinds of waste have produced the particular etymology 'municipal.' Composition The composition of municipal solid waste varies greatly from municipality to municipality, and it changes significantly with time. In municipalities which have a well-developed waste recycling system, the waste stream mainly consists of intractable wastes such as plastic film and non-recyclabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Sorting
Waste sorting is the process by which waste is separated into different elements. Waste sorting can occur manually at the household and collected through curbside collection schemes, or automatically separated in materials recovery facilities or mechanical biological treatment systems. Hand sorting was the first method used in the history of waste sorting. Waste can also be sorted in a civic amenity site. Waste segregation is the division of waste into dry and wet. Dry waste includes wood and related products, metals and glass. Wet waste typically refers to organic waste usually generated by eating establishments and are heavy in weight due to dampness. With segregation, each form of waste goes into its category at the point of dumping or collection, but sorting happens after dumping or collection. Segregation of waste ensures pure, quality material. Sorting on the other hand will end up producing impure materials with less quality. These days, automatic waste segregators a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodity Plastics
Commodity plastics or commodity polymers are plastics produced in high volumes for applications such as packaging, food containers, and household products, including both disposable products and durable goods. In contrast to engineering plastics, commodity plastics tend to be inexpensive to produce and exhibit relatively weak mechanical properties. Widely used commodity plastics include polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), poly(methyl methacrylate) (PMMA), and polyethylene terephthalate (PET). Products made from commodity plastics include disposable plates, disposable cups, photographic and magnetic tape, clothing, reusable bags, medical trays, and seeding trays. Further reading * Engineering plastic Engineering plastics are a group of plastic materials that have better mechanical or thermal properties than the more widely used commodity plastics (such as polystyrene, polyvinyl chloride, polypropylene and polyethylene). Engineer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Waste
Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are categorized by size into micro-, meso-, or macro debris. Plastics are inexpensive and durable, making them very adaptable for different uses; as a result, manufacturers choose to use plastic over other materials. However, the chemical structure of most plastics renders them resistant to many natural processes of degradation and as a result they are slow to degrade. Together, these two factors allow large volumes of plastic to enter the environment as mismanaged waste which persists in the ecosystem and travels throughout food webs. Plastic pollution can afflict land, waterways and oceans. It is estimated that 1.1 to 8.8'' ''million tonnes of plastic waste enters the ocean from coastal communities each year. It is estimated that there is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrothermal Liquefaction
Hydrothermal liquefaction (HTL) is a thermal depolymerization process used to convert wet biomass, and other macromolecules, into crude-like oil under moderate temperature and high pressure. The crude-like oil has high energy density with a lower heating value of 33.8-36.9 MJ/kg and 5-20 wt% oxygen and renewable chemicals. The process has also been called hydrous pyrolysis. The reaction usually involves homogeneous and/or heterogeneous catalysts to improve the quality of products and yields. Carbon and hydrogen of an organic material, such as biomass, peat or low-ranked coals (lignite) are thermo-chemically converted into hydrophobic compounds with low viscosity and high solubility. Depending on the processing conditions, the fuel can be used as produced for heavy engines, including marine and rail or upgraded to transportation fuels, such as diesel, gasoline or jet-fuels. The process may be significant in the creation of fossil fuels. Simple heating without water, anhydrous pyrol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furan
Furan is a Heterocyclic compound, heterocyclic organic compound, consisting of a five-membered aromatic Ring (chemistry), ring with four carbon Atom, atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly Volatility (chemistry), volatile liquid with a boiling point close to room temperature. It is soluble in common organic Solvent, solvents, including ethanol, alcohol, diethyl ether, ether, and acetone, and is slightly soluble in water. Its odor is "strong, ethereal; chloroform-like". It is toxic and may be carcinogenic in humans. Furan is used as a starting point for other speciality chemicals. History The name "furan" comes from the Latin ''furfur'', which means bran (furfural is produced from bran). The first furan derivative to be described was 2-furoic acid, by Carl Wilhelm Scheele in 1780. Another important derivative, furfural, was reported by Johann Wolfgang Döbereiner in 1831 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it requires careful handling because it can cause chemical burns. It is acutely toxic and is considered a health hazard. Phenol was first extracted from coal tar, but today is produced on a large scale (about 7 million tonnes a year) from petroleum-derived feedstocks. It is an important industrial commodity as a precursor to many materials and useful compounds, and is a liquid when manufactured. It is primarily used to synthesize plastics and related materials. Phenol and its chemical derivatives are essential for production of polycarbonates, epoxies, explosives such as picric acid, Bakelite, nylon, detergents, herbicides such as phenoxy herbicides, and numerous pharmaceuti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemical
Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research. Voet (2005), p. 3. Biochemistry focuses on understanding the chemical basis that allows biological molecules to give rise to the processes that occur within living cells and between cells, Karp (2009), p. 2. in turn relating greatly to the understanding of tissues and organs as well as organism structure and function. Miller (2012). p. 62. Biochemistry is closely related to molecular biology, the study of the molecular mechanisms of biological phenomena. Astbu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
