فهرست مطالب امیر حسین متین

Pulse jet systems are of interest due to their high filtration velocity,Theychr('39')re used as inlets from top and bottom. the purpose of this study was to compare the pressure drop and collection efficiency at the different inlet positions in a baghouse

In this experimental study, a pilot system was designed at 12ft/min permeability for MDF particles.For each inlet after several filtration-cleaning periods,pressure drop was measured by a manometer.Isokinetic sampling was also performed by Grimm1.108 monitor to determine the efficiency.To observe the behavior and Tyndall effect of particles, light and safety glass were used in one dimension of the baghouse

The mean pressure drop during the filtration-cleaning,the bottom inlet was 3CmWG, the top whit expansion inlet was 2.42CmWG,and the top flanged inlet was 2.57CmWG. but the particles settled on the expansion floor.The mean efficiency of top-expansion inlet was 99.995% and top-flanged 99.994%,significantly higher than the bottom inlet (99.974%).After several filtration-cleaning periods,The efficiency of  bottom inlet resulted 99.99%,top-expansion 99.97% and flanged 99.96%.There was no significant difference between the mean total efficiencies for different inlets.

The collection efficiencies were the same for baghouses with inlet from top and bottom.The pressure drop for baghouses with the top inlets was lower than the bottom inlet.It is recommended to use top inlets in case of predominantly fine particles with low density or in presence of a pre-separator,if  large particles,bottom inlet is recommended.Due to the slight difference of pressure drop and more functional limitation of the top inlet,bottom inlet in practice is preferred.

Investigating the hazardous factors and points in process industries through risk management and evaluation for preventing accidents is particularly important. Oil and gas refineries have several risks such as fire, explosion, or the release of toxic substances, which might have catastrophic and irremediable consequences. Conducting safety integrity level (SIL) studies in the process industries for assessing safety status and reliability of complex engineering systems is of particular importance. This study aimed to investigate the effectiveness of safety instrumented systems (SIS) in the isomerization unit of the gasoline production complex of Isfahan oil refinery, Iran. In the first part of the study, the semi-quantitative method of layer of protection analysis (LOPA) was used to analyze the layers of protection and determine the required SIL of the system (target SIL). In the second part, using the fault tree analysis (FTA), the existing SIL of the system was verified. Findings: In all selected scenarios, the existing SIL of system is consistent with the required SIL (target SIL). The frequency of final reduced event corresponded to the acceptable risk standard of the refinery as well, which indicated the adequacy of the existing independent protection layers (IPLs). Accurate designing and using the state-of-the-art equipment lead to an acceptable level of safety in this process, and the system is working with a proper reliability

Machines, especially pressing machines, have a huge contribution to the incidence of occupational accidents and their costs.
The purpose of this descriptive-analytical study was to evaluate the risk of pressing operations. For this purpose, two traditional and new methods of risk assessment were used.
This study was carried out in a press workshop of one of the automobile production factories in 2017. Risk assessment was performed in two ways: Failure modes (FM) and effects analyzes (EA) and functional resonance analysis method (FRAM) based on extended resilience engineering. After identifying the six aspects of the operation of pressing, their variability and exacerbation were determined.
Findings: From 72 potential breakdowns, twenty mode in one of the risk factors of the risk priority number (severity, probability and detection rates) were equal or greater than five, and other failure modes identified were normal and not require new corrective actions. Fifteen functions were also identified for press operations, which seven operations including planning, mapping, raw material supply, forklift lifting, stamping, census, and delivery of preformed parts were resonating.
Considering the focus of the method of FM and EA on technical issues and the visibility of this method, as well as the overall and organizational view, the FRAM, the simultaneous use of these two methods, significantly contributes to improving the safety of the system makes.

Spray tower is a cost effective and simple equipment for ammonia gas purification. But its’ appropriate performance in the removal of ammonia gas is under question. In this study, the effect of nozzle number, concentration of input ammonia gas and scrubbing liquid pressure over the removal efficiency of spray tower was studied.
In present study, a spray tower was used to remove ammonia from air at room temperature and barometric pressure of Tehran. Ammonia gas at average concentration of 24.1, 52 and 68 parts per million was injected into the tower. Water was applied at a volumetric flow rate of 5 liters per minute and at 9, 10 and 12 bar head as the scrubbing liquid. The air flow rate in 3737.8 liters per minute was adjusted by a variable speed fan. Scrubbing liquid was sprayed using 1, 2 and 3 nozzle settings with a 20 μm size. The collected data were analyzed using the SPSS software.
The highest removal efficiency of 88.38% and the lowest removal efficiency of 51.47% Were obtained. Increasing the number of nozzles did not increase the removal efficiency significantly (P-Value = 0.06).
Removal efficiency of spray tower decreased by increasing the input ammonia gas concentration. Increasing the number of nozzles mounted on the spray tower from 1 to 3 increased the removal efficiency. Increasing the scrubbing liquid pressure increased the removal efficiency of ammonia gas by spray tower. It is advisable to increase the size of the nozzle outlet and apply caustic scrubbing solution to get removal efficiencies of higher than 90%.

HSE performance assessment is one of important requirement for HSE improvement. Apparently, the previous HSE performance assessment models have not considered all of the performance assessment criteria. On the other hand, foreign models can not culturally be applied in describing HSE performance in Iranian organizations. Therefore, this study was conducted with the aim of developing a new model for assessing and ranking of HSE performance.
In this expanding practical study, firstly, previous existed HSE performance models were identified; afterwards, common and distinct criteria were extracted. Simultaneously, interviewing with experts was done and performance assessing criteria were recognized. For each criterion, some sub criteria and for each sub criterion, some bullet points were extracted. Finally, the weights of criteria and sub criteria were detected by paired comparison and Fuzzy analytical hierarchical process.
HSE performance assessment model was made of 9 criteria including safety results, health results, environment results, processes, economical and sociocultural results, policy and strategy, leadership, partnerships and resources, and human resources weighted respectively with 19 subcriteria and 157 guidance points.
Results criteria weighted more in comparison with enablers criteria. It was shown that processes, policy and strategy, and leadership weighted most part of enablers.. Processes weighted the highest score in enablers. Safety results gained the greatest rank of the results weight.