Analisis Penyebab Kerusakan Hot Rooler Table dengan Menggunakan Metode Failure Mode And Effect Analysis (FMEA)

This research was conducted in an international company engaged in iron and steel products manufacturing industries. One of the equipment that is often damaged is a hot roller table machine in the furnace section mill unit. The availability results obtained in hot roller table equipment is 96.571% and is still below the company standard which is set at 98%. Therefore, we need an analysis of the root causes of the problem and search for the best solution to fix the existing problem by applying the method of Failure Mode and Effect Analysis (FMEA). FMEA is a method that can systematically and structurally analyze and identify the consequences of a system or process failure, and also reduce or analyze the probability of failure. The purpose of this study is to identify and analyze the level of damage and its causes with the application of the FMEA method. Based on the pareto diagram the damage to the hot roller table machine, it was found that the highest frequency of damage was in the rotary coupling with a down time percentage of 26.9%. From the FMEA Analysis, two components that have very high RPN values are categorized as potential severit i.e. bearing as the first with an RPN value of 392 and the second is a seal ring with an RPN value of 294. The two components are the main priority for repair of the furnace section. mill, especially for machine and human aspects.

Effect of Boiler Feedwater Inlet Locations on the Water Circulation Characteristics in a Firetube Boiler With the Non-Symmetrically Arranged Tube Passes 3 and 4

Since the furnace section of a boiler is the primary heat transfer surface for the production of vapor, the overall water circulation patterns in the boiler will be significantly influenced by the circulation patterns near the furnace area. Boiler water circulation characteristics for a newly designed 4-pass firetube boiler with the non-symmetric arrangement of tube passes 3 and 4 were investigated in the previous work [1], in which the attraction forces between 28 different temperature nodes on the furnace wall were evaluated to predict the characteristics of water circulation near the boiler furnace. It was found that various non-symmetric water circulation patterns would occur for different firing conditions. As a consequence, in this paper, the analysis methods developed in the authors’ previous work are explicitly employed to predict and improve the water circulation in a firetube boiler when 6 different boiler feedwater inlet locations (3 on the right-hand side and 3 on the left-hand side of the boiler vessel shell) are used. Each side has 3 different feedwater inlet locations below the centerline of the boiler pressure vessel along its length. Investigation of the analysis results reveals that non-symmetric water circulation patterns are not unavoidable, but improvements in the water circulation and potentially the heat transfer rate can be achieved when the boiler feed water inlet is located near the front head of the boiler pressure vessel.