Utilization of waste heat (off gas) from electric furnace no.4 to generate saturated steam using waste heat recovery boiler

• Main Authors: Sitorus, Febrin, Soehartanto, Totok
• Format: Conference Proceeding
• Language: English
• Subjects: Baghouses; Boiler furnaces; Continuous furnaces; Design parameters; Electric arc furnaces; Electric furnaces; Energy management; Exhaust gases; Furnaces; Heat; Heat balance; Heat loss; Heat recovery systems; High temperature; Metallurgy; Nickel; Processing industry; Smelting; Waste heat recovery; Waste utilization; Water pollution
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5095314

The processing of nickel matte by electric furnace (electric arc furnace) are using a large input energy in the smelting process. The rest of the smelting process will produce in high capacity and temperature of waste heat. When waste heat discharges directly into the air, besides being a heat loss, the waste heat will also be a contributing factor of pollution in the air. PT Vale Indonesia (PTVI) is one of the nickel processing industry that have four (4) smelting electric furnaces that operates continuously and produce heat waste in the form of exhaust gas (off gas) with a high temperature in the range 600-800 °C. To meet of the exhaust gas regulation, PTVI builds exhaust gas handling facilities before being discharged into the air. Temperature of the exhaust gas will be lowered to about 350 °C by using a spray chamber, then in the second stage will be lowered to about 250 °C by adding secondary spray water before entering the baghouse and discharged into the air at 50 - 60 °C of average temperature. The main objective of this study is to recover waste heat from the electric furnace no.4 by utilizing heat energy from the exhaust gas before entering the spray chamber. The heat energy from the exhaust gas will be utilized to produce saturated steam by using Waste Heat Recovery Boiler (WHRB) by heating the water and converting the water into saturated steam 180 °C @ 10 Bar. This paper involves the (a) calculation of heat balance at electric furnace No 4, (b) Recover of the waste heat of off gas from the existing operation, (c) Generation of saturated steam in WHRB, (d) Financial evaluation for waste heat recovery boiler. This paper also will review the potential of waste heat when electric furnace operates in design parameter.