Recovery of heat energy
Most plastics are made of petroleum, mainly hydrocarbons, which can be burned. For example, polystyrene burns more heat than dye oil. Some experts believe that burning plastic waste in incinerator can provide heating or power generation heat because 86% of petroleum dyes are burned directly, only 4% of them are made into plastic products. It's normal to burn the plastic when it's used up. The use of heat energy is one of the last methods for plastics recycling, which should not be ignored. But many environmental groups oppose the burning of plastics. They believe that the burning method will produce toxic gases by burning all the messy chemicals. For example, half of the components of PVC are chlorine. The chlorine released during combustion has strong erosion and destructive power, and is the main culprit of evil.
At present, there are 200,000 tons of PVC garbage in Germany every year, 30% of which burns in incinerators, which makes people nervous, so the law has to formulate countermeasures. The German Federal Environment Agency has stipulated that all incinerators must meet the emission limit of less than 0.1ng (nag) per cubic metre. Although Germany's air pollution standard for incinerators has been recognized as a high standard in the world, it still can be said that combustion methods of it will not emit harmful substances due to mechanical failures. Therefore, it can be predicted that environmental groups in various countries will still vigorously oppose the incineration method to recover heat energy.
Classified Recycling Solution
As a method of plastic waste recycling, the most important thing is to classify. Common plastics are polystyrene, polypropylene, low density polyethylene, high density polyethylene, polycarbonate, polyvinyl chloride, polyamide, polyurethane and so on. The differences between these plastics are difficult to distinguish. Nowadays, the classification of plastics is mostly done manually. Recently, new advances have been made in waste plastic recycling equipment. A German chemical science and Technology Association has invented infrared to identify categories. It is fast and accurate, but the cost of sorting is high.