This year, HANS HENNIG realized the conversion of heavy oil to natural gas furnace in a steel mill in Indonesia. Mid-2008, our company won the contract to convert a walking beam furnace in the section mill 'Krakatau Wajatama' in Cilegon, Indonesia, of heavy oil to natural gas. The order was given by Krakatau Engineering through our office in Jakarta. Due to our high manufacturing depth and specialization, this project was perfect for our company. However, the project was initially delayed because of the economic crisis. After a 6 month delay, assembly and commissioning took place at the end of July 2009. The existing 75t walking beam furnace was heated with heavy oil before the conversion.
The furnace was ignited using fuses. An automatic flame monitor was installed by us. The existing field devices such as transmitters, limit switches, photo-electric switches and the like were to be partially replaced in a dilapidated state and needed by modern spare parts. Due to the lack of field devices, the furnace was operated only manually. An automatic mode was included in delivery. Since the furnace was regulated not automatically it led to an increased scale formation caused by the sometimes very high air pressures in the combustion. By using new control systems and switching to natural gas, the scale thickness could already be reduced during the commissioning of 7 mm to about 1 mm. A further reduction of scale formation is expected after the fine adjustment in the spring of 2010.