Plastic material refining

Industry Agricultural chemicals Paints and allied products Petroleum refining plastic materials and resins Soap and other detergents... 

Life-cycle analysis of a filter shows that operation often corresponds to 70% to 80% of the filter s total environmental load and is absolutely decisive as regards environmental effect. Raw material, refining, manufacturing, and transports correspond to about 20% to 30%, while the used filter contributes at most 1%. Filters of plastic or other inflammable material can render 10 kWh to 30 kWh energy when burned, which correspondingly reduces the total environmental load from 0.5% to 1%. On the other hand, if the pressure loss in the filter is reduced by 10 Pa, the environmental load is reduced by 125 kW h per year, or approximately 5% decrease in total environmental load. Filters in industrial applications can have quite different figures. 

To pursue the goal of obtaining a simple formula for the estimation of DB which does not rely on experimental diffusion data, reference Eq. (6-20) for all plastic materials was developed (Brandsch et al. 1999). The theoretical assumptions for this equation are given in Chapter 6. Following the approach treated in Chapter 6 a refined equation for DP resulted ... 

Signal flares, marine Sizes animal, vegetable, and synthetic plastics materials Sodium chloride, refined Soil testing kits Speai mint oil Spirit duplicating fluid Stearic acid... 

Western-world bauxite production in 1988 totaled about 90 x 10 t, approximately 90% of which was refined to aluminum hydroxide by the Bayer process. Most of the hydroxide was then calcined to alumina and consumed in making aluminum metal. The balance, which constituted about 2.3 x 10 t in 1988 (Table 2), was consumed in production of abrasives (qv) adhesives (qv) calcium aluminate cement used in binding ceramics (qv) and refractories (qv) catalysts used in petrochemical processes and automobile catalytic converter systems (see Petroleum Exhaust control, automotive) ceramics that insulate electronic components such as semiconductors and spark plugs chemicals such as alum, aluminum halides, and zeoHte countertop materials for kitchens and baths cultured marble fire-retardant filler for acryhc and plastic materials used in automobile seats, carpet backing, and insulation wrap for wire and cable (see Flame retardants) paper (qv) cosmetics (qv) toothpaste manufacture refractory linings for furnaces and kilns and separation systems that remove impurities from Hquids and gases. 

Plastic materials are those that are formed from synthetic compounds e.g., polymers or natural compounds that have previously been modified, for example hydrocarbons refined from crude oil, natural gas or derivatives of ethane, methane and naphtha. By definition the manufacturing of a plastic component should include a viscous flowing process that usually requires heat and pressure, for example extrusion or injection moulding. 

Embodied energy in plastic material can be compared to that for other materials" as shown in Table 4.6. Plastics are more energy intensive to produce than most materials of construction in the table except for aluminum. Like aluminum, plastics also have to be removed from a finite in-ground resource pool and have to be refined before use both can be recycled as well. 

Catalytic polymerization processes have become increasingly important as the use of plastics has escalated throughont the world. Many common plastics were discovered in the 1930s, and after the 1939-1945 war tto created a demand for petrochemical intermediates derived from the refining industry. Ethylene and propylene are now common building blocks for plastics and by the year 2000, polyethylene, polypropylene and their copolymers were the most widely nsed plastic materials. The gradual development of polyolefin production is shown in Table 8.1. 

A rather impressive Hst of materials and products are made from renewable resources. For example, per capita consumption of wood is twice that of all metals combined. The ceUulosic fibers, rayon and cellulose acetate, are among the oldest and stiU relatively popular textile fibers and plastics. Soy and other oilseeds, including the cereals, are refined into important commodities such as starch, protein, oil, and their derivatives. The naval stores, turpentine, pine oil, and resin, are stiU important although their sources are changing from the traditional gum and pine stumps to tall oil recovered from pulping. 

Fiber-reinforced composite materials such as boron-epoxy and graphite-epoxy are usually treated as linear elastic materials because the essentially linear elastic fibers provide the majority of the strength and stiffness. Refinement of that approximation requires consideration of some form of plasticity, viscoelasticity, or both (viscoplasticity). Very little work has been done to implement those models or idealizations of composite material behavior in structural applications. 

Relative crystallinity undoubtedly influences such properties of cellulosic materials as rigidity, flexibility, plasticity and extensibility. Likewise the amount and reactivity of intercrystalline cellulose are major factors in common processing treatments such as bleaching, dyeing, pulping and wet finishing. Further refinement of measuring methods and the development of further correlations between crystallinity and fiber properties would contribute much to this important field. 

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