Plastics scrap

In the Texaco process, there are two steps, an initial liquefaction step followed by treatment in an entrained bed gasifier. The liquefaction step involves heating the plastic scrap in such a way that partial depolymerisation occurs, generating a heavy oil and some gas fractions. Some of the gas is recycled as fuel for the process. 

Three recycling news items are very briefly reported upon a Canadian-developed pyrolysis technology that converts plastics scrap into alpha-olefins, a scrap-plastics-to-monomers system under construction in Scotland, and statistical forecasts on chemical recycling in Germany for 1996. 

It is claimed that only by fully considering all stages of the life cycle is it possible to arrive at a meaningful evaluation of a product. Thus the feasibilities and limitations of recycling are important, but are not the only aspects of the matter. Also discussed are the utilisation of plastics scrap as a raw material and energy carrier, and techniques under development. 11 refs. 

Rubber and miscellaneous Manufacture of fabricated rubber and plastic Scrap rubber and plastics, lampblack, curing... 

The Blue Streak dual-screen pulverizer (Prater Industries, Inc.) is used for the grinding of resins, chemical salts, plastic scrap, food products, and similar materials to a granular uniform powder of No. 30 or No. 40 sieve fineness. Feed enters opposite ends of the rotor and undergoes three stages of size reduction by hammers of decreasing size. Two perforated) screens cover more than 70 percent of the area of the fini sizing drum through which the product passes. 

K. Saito and M. Nanba Method for thermal decomposition of plastic scraps and apparatus for disposal of plastic scraps, US Patent 4,584,421, 1986. 

Figure 15.4 A schematic of a typical continuous stirred tank pyrolysis process. Legend 1 pyrolysis vessel with internal agitator 2 catalyst chamber 3 plastic feedstock hopper 4 char auger to remove solid residue 5 agitator drive motor 6 lower temperature sensor 7 upper temperature sensor 8 burner for furnace 9 feed auger for plastic feedstock 10 condenser cooling jacket 11 condenser 12 oil recovery tank (adapted from Saito, K. and Nanba, M., United States Patent 4,584,421 (1986) Method for thermal decomposition of plastic scraps and apparatus for disposal of plastic scraps )...

Plastics-Recycling. 2. Pyrolysis. 3. Plastic scrap-Recycling. 1. 

As a general example for contaminated plastic scrap we pyro— lyzed shreddered syringe materials - containing polyethylene, polypropylene and rubber (Table II). The pyrolysis of these syringes is without doubt hygienic and gives nearly the same products as... 

Figure 1.13 Processing of plastic wastes in refinery units.19 VVA pre-treated mixed plastic scrap AR residue from the atmospheric distillation process VR vacuum distillation residue VisR visbreaker residue VVR vacuum visbreaker residue.

Figure 5.16 Schematic diagram of an apparatus for the thermal and/or catalytic degradation of plastic scraps.41...

Plastic deformation Plastic lumber/wood Plastics consumption Plastics production Plastics scrap collection... 

Some plastics scraps are not suited for initial reduction in a shredder described above. These include fibers, long pieces of material, rolled strips, and lumps of rubber. A guillotine is better for... 

Fine grinding also offers solutions for the recycling of plastic scrap. Different types of machines are used, two common types being universal blast mills and disc pulverizers. In a universal blast mill, plastic scarp is reduced between the beater wings of a blast disc and a screen or the grooved grinding track of a grinding chamber. The hole size of the screen determines the fineness of the plastic powder. This usually has an upper size limitation of 500-800 nm. 

Material is fibrous or flaky with a relatively low bulk density of 3-20 Ib/ftj. Particle sizes are from 1/8 in. strands to 1 in. or larger chips has a tendency to interlock and absorb vibration. Examples are wood chips, slivers, shavings, plastic scraps, flaked grains. 

Among the factors to be considered when ordering from a supplier of laboratory chemicals is whether the supplier will accept return of unopened chemicals, including highly reactive chemicals. Materials other than chemicals, such as containers or packaging materials and parts of laboratory instruments, can also be recycled. Examples include certain glass and plastic containers, drums and pads, plastic scrap and film scrap, cardboard, office paper, circuit boards, and metals such as steel and aluminum. 

Tertiary recycling is the production of basic chemicals or fuels from segregated plastic scrap or plastic material that is part of a municipal waste stream or other source. ... 

---