Ppbb01-kelompok 7-rotary Hearth Furnace 54e5b

GROUP

7

ROTARY HEARTH FURNACE

Arini Mulia Salsabila Arum Cahyanurani S. Irene Angela Muhammad Adli

Evolution of Direct Reduction Technologies The process available for direct reduction can be broadly categorised into those using non-coking coal and those using natural gas and other gases. The preference for a particular type of direct reduction technology has come in waves at different periods of time has summarised in table below.

The genesis of Rotary Hearth Process is to make the reduction step faster by increasing area of between the oxide and the reductant

Principles of Heating in a Rotary Hearth Furnace Iron ore forms an approx. thin layer on the furnace hearth in the form of pellets or fines without any agglomeration

Bed moves slowly as CO2 and H2 works as a reductant RHF promotes no heat transfer except radiation, makes temperature in this process can reach at least 800C REDUCTION STAGES IN ROTARY HEARTH FURNACE

THE EFFECT OF THICKNESS/ LAYERS ON THE PROCESS

Pre-heating zone Materials gets heated to 600C

Pre-reduction zone The majority of iron oxide is reduced to FeO

Within 15 minutes Pellets (input) are made of Very fine iron ore (under 250 micron) Fine coal Small quality of lime Bentonite as binder

Final Reduction Zone FeO reduced to itom 20 minutes

RHF-Blast Furnace Combination

Most of sulfur and slag in coal remain in the output of RHF proces. Thus RHF needs a smelting process in order to remove them.

RHF-Smelting Furnace Combination Cold ore needs approximately 10GJ/t-HM meanwhile hot direct reducted iron can reduce energy by approximately 3GJ/t-HM.This process can reduce not only energy consumption but also the smelting furnace size

Direct reduction iron made by rotay heat furnace is charged to smelting furnace directly in order to utilize the sensitive heat of direct reduction iron and then smelting furnace will produce pig iron

PROCESS FLOW CHART AND REACTIONS

PROCESS REACTION

• Oxidation of natural gas with presence of heat and catalyst: 2CH4 + O2 -> 2CO + 4H2 • Reaction between gas and iron ore, producing sponge iron: Fe2O3 + CO -> 2Fe + CO2 + 2H2O

PRODUCT SPECIFICATION

Product Specification 

RHF process will result in high purity iron nuggets. Hasil akhir dari proses ini adalah iron nuggets dengan kemurnian yang tinggi.



Iron nuggets could be utilized as a substitution to pig iron in the use of EAF method in steel making. Iron nuggets sendiri dapat menjadi pengganti yang baik untuk pig iron dalam proses pembuatan baja dengan EAF.

Product Specification 

Common dimension of iron nuggets formed is ranging from 5-25 mm with a high density of 7.4-7.6 kg/m3. Iron Nuggets yang terbentuk biasanya memiliki ukuran sebesar 5-25 mm dengan densitas yang tinggi yaitu sekitar (7,4-7,6 Kg/m3).



Produced nuggets will not experience oxidation, hence could be straightly put into EAF and used for steelmaking process. Dan nuggets dari proses tidak akan mengalami oksidasi kembali sehingga dapat langsung dimasukkan ke dalam EAF untuk dijadikan baja.

Product Specification Iron nuggets are composed of: Komposisi nuggets:    

C = 2,5 - 3,0 % P = 0,01 - 0,02 % S = 0,05 - 0,07 % Fe = 96,0 - 97,0 %

Product Specification 

RHF process tend to be more environmental friendly and demanding less energy requirement. Proses Rotary Hearth ini lebih ramah lingkungan membutuhkan konsumsi energi yang lebih rendah.

dan

ADVANTAGES • More efficient to be used in steelmaking industry producing scrap metal • Lower CO2 emission per ton compared to those in blast furnace use • Lower operational cost

DISADVANTAGES • RHF productivity is limited to the amount of heat transfer • Complex design is required

MIDREX PROCESS MIDREX direct reduction ironmaking

• Utilize natural gas to reduce iron ore. • Produces direct reduced iron (DRI) – used as material for EAF and hot briquette iron (HBI) – used for steelmaking and rolling process. Specification

DRI

HBI

Fe total (%)

90-94

90-94

Fe metallic (%)

83-89

83-89

Bulk density (t/m3)

1.6-1.9

1.6-1.9

Apparent density (t/m3)

3.4-3.6

5.0-5.5

40

80

Discharge temperature (oC)

MIDREX PROCESS MIDREX direct reduction ironmaking

MIDREX PROCESS MIDREX direct reduction ironmaking

GROWTH OF MIDREX CAPACITY

FEEDSTOCK OPTIONS Pellets

Lump

MIDREX PROCESS MIDREX direct reduction ironmaking

CHARACTERISTICS OF FEED:

MIDREX PROCESS MIDREX direct reduction ironmaking

-> MIDREX process flow sheet

MIDREX PROCESS MIDREX direct reduction ironmaking

• Reaction of iron reduction inside the shaft furnace is described as follows: Fe2O3 + 3CO -> 2Fe + 3CO2 Fe2O3 + 3H2 -> 2Fe + 3H2O • While the reaction that occurs in the reformer tubes filled with nickel catalysts, ed through by mixture of tops gas and natural gas, producing reductant gas is described by the following reaction: CH4 + CO2 -> 2CO + 2H2 CH4 + H2O -> CO + 3H2 2 CH4 + O2 -> 2CO + 4 H2 CO + H2O -> CO2 + H2 CH -> C + 2H

REFERENCES RHF – GROUP 7

Atsushi Masaaki, Uemura Hiroshi. Midrex® Processes. Kobelco Technology Review No. 29 (2010) http://www.midrex.com. Monday, 13-3-2017, 15.30 P.M. http://mmmmconferences.com/01JyunpeiKikuta_29Sept2012.pdf. Saturday, 11-32017, 10.33 A.M. http://www.tlzchina.com. Sunday, 12-3-2017, 12.32 P.M.