Kajian Efisiensi Thermal Pada Mesin Reheating Furnace Tipe Walking Beam Dengan Bahan Bakar Gas Alam

MADE SANJAYA BASKARA, Ir. Purnomo MSME., Ph. D

2015 | Skripsi | S1 TEKNIK MESIN

Mesin Reheating Furnace merupakan sebuah mesin yang digunakan untuk memanaskan baja hingga mencapai temperatur tertentu. Pemanasan ini dilakukan untuk mengubah sifat material, dan melakukan proses permesinan (heat treatment). Tujuan dari penelitian ini adalah untuk mengetahui besarnya efisiensi thermal mesin reheating furnace tipe walking beam di divisi Hot Strip Mill, PT. Krakatau Steel (Persero) Tbk. yang digunakan untuk memanaskan slab steel dengan kandungan karbon sangat rendah (ultra-low carbon) yaitu di bawah 0.5 %. Mesin reheating furnace tipe walking beam ini memiliki dimensi panjang 37 m, lebar 12.8 m, tinggi 6 m, dan ketebalan dinding 0.5 m. Di dalam mesin reheating furnace tipe walking beam ini memiliki 3 zona pemanasan, zona tersebut adalah zona Preheating (700 derajat Celcius sampai dengan 900 derajat Celcius), zona Heating (900 derahat Celcius sampai dengan 1100 derajat Celcius), dan zona Soaking (1100 derajat Celcius sampai dengan 1200 derajat Celcius). Sensor-sensor yang digunakan untuk memperoleh data-data penelitian adalah thermocouple ( pada dinding furnace dan cerobong), control valve ( inlet bahan bakar gas alam, inlet udara pembakar, serta debit water cooling). Hasil penelitian ini menghasilkan bahwa efisiensi thermal mesin reheating furnace tipe walking beam di divisi Hot Strip Mill PT. Krakatau Steel (Persero) Tbk. adalah sebesar 55.83 %. Dengan energi kalor yang terkandung dalam bahan bakar gas adalah sebesar 212221907.6470 kJ/jam. Dari energi kalor tersebut 118487178.1253 kJ/jam, digunakan untuk memanaskan slab steel, dan sisanya hilang karena beberapa faktor, diantaranya adalah gas buang (31488493.4505 kJ/jam), water cooler (29502616.7759 kJ/jam), pintu discharge dan charge (7869038.4298 kJ/jam), dinding furnace (10969024.4863 kJ/jam) dan faktor lainnya (13905556.3793 kJ/jam).

Reheating Furnace machine is a machine that is used to heat the steel to reach a certain temperature. Heating is done to change the material properties, and perform machining processes (heat treatment). The purpose of this study was to determine the thermal efficiency of the engine type of walking beam reheating furnace in Hot Strip Mill division, PT. Krakatau Steel (Persero) Tbk. which is used to heat the steel slab with very low carbon content (ultra - low carbon) is below 0.5%. The magnitude of the thermal efficiency of the engine type of walking beam reheating furnace, can be determined by looking calorific value of natural gas fuel used and perform the calculation of the thermal energy used and heat energy is lost and used to heat the steel slab. Engine type reheating furnace walking beam has dimensions 37 m long, 12.8 m wide, 6 m high, and a wall thickness of 0.5 m. In the machine-type reheating furnace walking beam has 3 heating zones which are the zones each thermocouple which serves to monitor the temperature in the zone. Zone - the zone is Preheating zone (700 Degree of Celcius until 900 Degree of Celcius), Heating zone (900 Degree of Celcius until 1100 Degree of Celcius), and Soaking zone (1100 Degree of Celcius until 1200 Degree of Celcius). Sensors - sensors that are used to obtain data - research data is a thermocouple (on the furnace walls and chimneys), control valve (inlet natural gas fuel, burner air inlet and discharge water cooler). The results of this study suggest that the thermal efficiency of the engine type of walking beam reheating furnace in Hot Strip Mill division of PT. Krakatau Steel (Persero) Tbk. amounted to 55.83%. With the heat energy contained in the fuel gas is equal to 212221907.6470 kJ/h. Of the heat energy 118487178.1253 kJ/h, is used to heat the steel slab, and the rest is lost due to several factors, including the exhaust gas (31488493.4505 kJ/h), water cooler (29502616.7759 kJ/h), the door discharge and charge (7869038.4298 kJ/h), wall furnaces (10969024.4863 kJ/h) and other factors (13905556.3793 kJ/h).

Kata Kunci : mesin reheating furnace tipe walking beam, stoikiometri, heat loss, heating value