Use of waste plastics in cokemaking at Tata Steel

Krishnan, S. H.; Sharma, Rahul; Dash, Pratik Swarup; Haldar, S. K.; Biswas, Biplob Kumar

doi:10.1179/174328106x113959

Cited by 14 publications

(7 citation statements)

References 3 publications

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“…The carbonization of coal to produce metallurgical coke is considered as one possible route for recycling plastic wastes of different structure and origin. Recently, integrated steel plants made a further contribution to plastics recycling by applying it to the blast furnace [1][2][3][4][5][6] and the carbonization processes [7][8][9][10][11][12][13][14][15][16]. In 2000, the Nippon Steel Corporation (NSC) began the industrial application of plastic wastes as minor components of coal blends for blast-furnace coke production at the Nagoya and Kimitsu works with a recycling capacity of 80,000 t/year [8,9].…”

Section: Introductionmentioning

confidence: 99%

Relevance of the composition of municipal plastic wastes for metallurgical coke production

Melendi

Díez

Álvarez

et al. 2011

Fuel

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This study is concerned with the effects of the composition of mixed plastic wastes on the thermoplastic properties of coal, the generation of coking pressure and the quality of the resulting cokes in a movable wall oven at semipilot scale. The mixed plastic wastes were selected to cover a wide spectrum in the relative proportions of high- and low-density polyethylenes (HDPE and LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). From the results it was deduced that the reduction in Gieseler fluidity in the coal blend is linked to the total amount of polyolefins in the waste. It was also found that these thermoplastics increase the pressure exerted against the wall in the course of the coking process and that coke quality is maintained or even improved. However, when the level of aromatic polymers such PS and PET are increased at the expense of polyolefins, the coking pressure decreases. Thus, the amount of aromatic polymers such as PS and PET in the waste is critical, not only for controlling Gieseler fluidity and coking pressure, but also for avoiding deterioration in coke quality (reactivity towards CO CRI and mechanical strength of the partially-gasified coke CSR). An amount of polyolefins in the waste lower than 65 wt.% for a secure coking pressure is established. © 2011 Elsevier Ltd All rights reserved

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Section: Introductionmentioning

confidence: 99%

Relevance of the composition of municipal plastic wastes for metallurgical coke production

Melendi

Díez

Álvarez

et al. 2011

Fuel

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“…As for the effect of plastic type, there have been many studies on the influence of plastic addition on coal-caking property and coke quality [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. It was revealed that thermal decomposition products of plastics interacted with bituminous coal during carbonization in a coke oven.…”

Section: Influence Of Plastic Addition On Coke Qualitymentioning

confidence: 99%

Use of Waste Plastics in Coke Oven: A Review

Nomura

2015

J. Sustain. Metall.

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To help in building a recycling-oriented sustainable society, Nippon Steel & Sumitomo Metal Corporation developed a waste plastic-recycling process using coke oven and put it into commercial operation in 2000. Now roughly 200,000 tons per year of waste plastics are processed in coke oven in Japan. In this process, the waste plastics collected from households are agglomerated to the sizes ranging from 20 to 30 mm in diameter and charged into coke ovens with coal at the blending ratio of about 1 mass%. Waste plastics are thermally decomposed into approximately 20 mass% coke, 40 mass% hydrocarbon oil (tar and light oil) and 40 mass% coke oven gas, which are utilized as iron ore-reducing agents in blast furnaces, raw materials for the chemical industry, and a fuel for power plants, respectively. Moreover, 92 mass% of the chlorine in waste plastics is released and absorbed by the ammonia liquor spray for cooling hot coke oven gas and converted to ammonium chloride. The waste plastic-recycling process using coke ovens is superior in that a large amount of waste plastics can be treated, useful materials can be recovered using the existing facilities, coke quality can be kept the same and the chlorine released from waste plastics can be fixed in the existing ammonia liquor spray system.

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“…During non-blast furnace ironmaking, the gas-based reduction process is implemented using pressure. Many experts' studies on the mechanism of inhibiting sticking loss are mostly based on atmospheric pressure and differ from the production practice.In order to improve environmental protection and production efficiency, the current study added energetic waste plastics into the iron ore powder [16] according to a certain size and ratio, resulting in the changing direction of the optimal operating parameters in a self-designed, hot visual, pressurized, fluidized bed experimental device. On this basis, economic, convenient, and effective operating parameters were determined.…”

mentioning

confidence: 99%

“…In order to improve environmental protection and production efficiency, the current study added energetic waste plastics into the iron ore powder [16] according to a certain size and ratio, resulting in the changing direction of the optimal operating parameters in a self-designed, hot visual, pressurized, fluidized bed experimental device. On this basis, economic, convenient, and effective operating parameters were determined.…”

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confidence: 99%

The Effect of Carbon Dissection of Waste Plastics on Inhibiting the Adhesion of Fine Iron Ore Particles during Hydrogen Reduction

Liu

et al. 2018

Metals

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In this research, Australian fine iron ore was reduced by combining pressurized and energy-bearing waste plastics in a fluidized bed. This research aims to obtain preferable operating parameters by synthetically researching the effect of temperature, linear velocity, pressure, size, and mass content of energetic waste plastics, and to clarify the sticking mechanism and the inhibitory mechanism of fine iron ore during the reduction process. The experimental results show that the preferable operating parameters include a reduction temperature of 923-973 K, linear velocity of 0.8 m/s, reduction pressure of 0.15 MPa, particle size of energetic waste plastics of 0.18-0.66 mm, and mass content of energetic waste plastics of 8%. Under the conditions of theses preferable operating parameters, the sticking mechanism of fine iron ore is caused by the reunion of the metal iron atoms. The occurrence states of carbons deposited from waste plastics can be divided into two types: graphite and carbon from Fe 3 C. Carbon from Fe 3 C reduces the sticking of fine iron ore, while the graphite hinders the direct contact of iron atoms, thereby effectively controlling the sticking.added are mainly oxides, such as CaO, MgO, SiO 2 , and Al 2 O 3 . The adding methods include the dry method, powder method, water mixing method, sintering method, solution method, slurry method, and high-temperature coating method [6][7][8][9]. The addition of inert components affects the surface morphology of particles, especially the growth of iron whiskers [9]. Moreover, the inert components wrap the surface of slag particles or the dilution bed and reduce the probability of iron contact on the surface of particles. Therefore, the inhibitory effect and inert ingredients' uniformity on the particle surface are related to adhesion strength.Carbon is attached to the surface of the particles through carbon precipitation and chemical reactions, and its uniformity distribution and adhesion strength are improved compared with those for the method of adding oxides [10,11]. Shi et al. [12] found that the adhesion of carbon effectively inhibits growth of iron whiskers, which are not easily generated on the surface of powder particles, thereby inhibiting sticking loss. This theory is based on the fact that powder sticking is caused by the hook of an iron whisker. However, Mikami, Zhong, and Shao et al. [13][14][15] showed that the iron whisker is not a necessary condition for the occurrence of sticking loss; pure iron powder particles can also generate sticking loss, and pure iron powder contains no iron whisker. Therefore, the mechanism of inhibition of sticking by carbon precipitation must be further studied. During non-blast furnace ironmaking, the gas-based reduction process is implemented using pressure. Many experts' studies on the mechanism of inhibiting sticking loss are mostly based on atmospheric pressure and differ from the production practice.In order to improve environmental protection and production efficiency, the current study added energetic waste pl...

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Use of waste plastics in cokemaking at Tata Steel

Cited by 14 publications

References 3 publications

Relevance of the composition of municipal plastic wastes for metallurgical coke production

Relevance of the composition of municipal plastic wastes for metallurgical coke production

Use of Waste Plastics in Coke Oven: A Review

The Effect of Carbon Dissection of Waste Plastics on Inhibiting the Adhesion of Fine Iron Ore Particles during Hydrogen Reduction

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