RUS| DonNTU> Master's portal
Donetsk National Technical University Konchenko Ekaterina

ABSTRACT

Theme of master's work:

"The organization of resource saving technology in blast furnace with plastic wastes"

Leader of work: as. prof. Kochura Vladimir

Biography| Library| Links| Report about the searcn| Individual task

The problem of recycling and neutralization of plastic wastes is one of the most significant global problems in the field of environment protection.

Existing in the majority of large cities of our country the system of the reference with waste products is based on range burial place. Nowadays in the majority of cities of Ukraine the resource of existing ranges is close to exhaustion that demands urgent radical revision of the developed circuit of the reference with waste products.

In response the integrated waste plastics system was developed. The technology for charging waste plastics into a blast furnace was brought into practical application in Germany, Japan, India.

As the basic unit is used a blast furnace since it is one of the best units from the point of view energy-and resourcesaving. A determining problem of blast furnace technology is reduction of the specific charge of coke. By manufacture of pig-iron of one of technologies of reduction of the charge of coke both industrial and household waste products of plastic are used.

Plastic after preliminary preparation can be injected into the blast furnace as additional fuel with dust coal fuel, providing a high degree of fuel combustion and an opportunity of waste products recycling.

Injecting the waste plastics into blast furnace as a supplemental fuel has the following advantages. Firstly, this method can consume large quantity of waste plastics. Secondly, it has higher energy efficiency of up to 80% when compared to other waste plastics treatment methods. Finally, it is environmentally less hazardous due to the lack of dioxin generation.

Waste plastics are largely grouped into lumpy solid and films. Lumpy solid plastics can be pre-processed by the combination of a conventional crusher and pulverizer. However, simple crushing of filmy waste plastics was found to produce a fluff of plastics, which caused serious problems by fouling the dispenser tank and clogging the pneumatic transport pipeline.

For pneumatic transfer of the pre-processed plastics, optimization of the solid/air weight ratio is critically important. If the solid/air ratio is large (high transportation rate), problems during transportation such as plugging of the transfer pipeline are likely occur. On the other hand, reducing the solid/air ratio (low transportation rate) increases the equipment and operation cost. When the particle size of the pre-processed waste is reduced, transportation and gasification in the raceway become easy, but the pulverization and pelletization cost increases.

There are many additional controlling variables, such as the pipeline size and air pressure, and these variables interact each other. Accordingly, optimization of the design of operating conditions has been established.

The general scheme of processing and use of waste plastic on the given technology is submitted on figure 1.

The scheme

The collected waste plastics are classified by shape as either lumpy solid or films. The classified waste plastics are crushed and palletized, and then held in a storage silo as pre-processed waste plastics are transferred to the dispenser tank before being charge into the blast furnace. The pre-processed waste plastics are pneumatically transferred from the dispenser tank by compressed air for injection into the hot blast through tuyers.

The pre-processed waste plastics are immediately converted into reducing gases (CO, H2). They reduce the iron ore (iron oxide), which ascends in the blast furnace, and heat and melt the ore. This function is similar to the reducing function of coke and pulverized coal. Therefore, the waste plastics provide a substitute for coke and pulverized coal.

The recycling scheme of processing and use of waste plastic in the blast furnace recycles waste plastics, which are conventionally incinerated or dumped in landfill without reuse, as a raw material for the blast furnace.

Features of recycling system are the following:

  • the system reduces the volume of dumped plastic waste;

  • the system eliminates the need for landfill sites for plastic waste;

  • the system decreases coke consumption, which saves coal resources that fully depend on imports;

  • the system decreases the emissions of carbon dioxide, thus contributing to measures against global warning;

  • the system does not generate toxic by-product gases, and the less toxic by-products gases are reusable in existing plants for power generation, etc.;

  • the system offers approximately 80% or more total energy efficiency in the blast furnace, so the system is superior to other recycling processes in terms of resource and energy conservation.

    • Biography| Library| Links| Report about the searcn| Individual task