Assessment and control design for steam vent noise in an oil refinery

Noise is one of the most important harmful agents in work environment. Noise pollution in oil refinery industries is related to workers' health. This study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. This experimental study performed in control unit of Tehran Oil Refinery in 2008. To determine the noise distributions, environmental noise measurements were carried out by lattice method according to basic information and technical process. The sound pressure level and frequency distribution was measured for each study sources subject separately was performed individually. According to the vent's specification, the measured steam noise characteristics reviewed and compared to the theoretical results of steam noise estimation. Eventually, a double expansion muffler was designed. Data analysis and graphical design were carried out using Excel software. The results of environmental noise measurements indicated that the level of sound pressure was above the national permitted level [85 dB [A]]. The Mean level of sound pressure of the studied steam jet was 90.3 dB [L]. The results of noise frequency analysis for the steam vents showed that the dominant frequency was 4000 Hz. To obtain 17 dB noise reductions, a double chamber aluminum muffler with 500 mm length and 200 mm diameter consisting pipe drilled was designed. The characteristics of steam vent noise were separated from other sources, a double expansion muffler was designed using a new method based on the level of steam noise, and principle sound frequency, a double expansion muffler was designed

Evaluation of noise propagation characteristics of compressors in Tehran oil refinery center and presenting control methods

The adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. Oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. The objective of this study was to evaluate the noise characteristics of compressors in Tehran Oil Refinery and study on visible control measures. To get to the appropriate control method, procedures such as basic theories, measuring sound parameters, frequency analysis, related diagrams and noise propagation schemes due to the measurement results, equivalent noise exposure level [L[eq[8h]]] and exposure noise dose and technical specification of compressors are considered in this paper. Considering field and analytical results, module enclosure with particular specifications [like absorbent layer, specific wall, window and door design etc.] is predicted to be the best control method. Calculation results of multiple layer density of the enclosure [W=16.5 kg/m[2]] and needed density for the dominant frequency of the source [W=12 kg/m[2]] demonstrated that the designed enclosure satisfies the goal. Results of designing sandwich layers' module demonstrated that installing the designed enclosure causes 20 dB[A] reduction in total sound pressure level of the source's dominant frequency