Batch processes play a key role in producing low-volume and high-value-added products. In order to produce consistent, high-standard products and ensure process safety, real-time monitoring of batch processes is critical. To this end, the present work proposed a batch processes monitoring method based on the multiway principal polynomial component analysis (MPPCA). The MPPCA-based monitoring method is a nonlinear technique used to tackle the problem of process nonlinearity inherent in most batch processes. Thus, the MPPCA-based monitoring method is more suitable for nonlinear process applications than traditional linear methods such as principal component analysis (PCA)-based monitoring methods. Moreover, as compared to other nonlinear monitoring methods such as kernel-based methods, the MPPCA-based monitoring method has attractive features of invertibility, volume-preservation, and straightforward out-of-sample extension. The effectiveness of the proposed MPPCA-based monitoring method was validated through its application to a fed-batch penicillin fermentation process. The application results have demonstrated that the proposed MPPCA-based monitoring method is superior to the conventional multiway PCA (MPCA)-based monitoring method and the multiway kernel PCA (MKPCA)-based monitoring method in fault detection and diagnosis performance.
Many accidents have occurred in universities and the accident reports are accumulated in most universities. The information described in the accident reports must be used effectively to prevent a recurrence of the accidents. In this study, we applied text analytics to the description written in 373 accident reports in a university as a case study. Information mining method was adopted for the contents analysis, and 9 factors based on human error and m-SHEL, that is “slip”, “lapse”, “mistake”, “violation”, “software”, “hardware”, “environment”, “liveware”, and “management” were used for morphological analysis for description in report. The factors in each category (e.g. accident situation, generation) were extracted, and it is suggested that text analytics is one of the most effective methods to analyze the accident reports in universities.
Storage tank fires (such as pool fires) often occur in petrochemical tank farms. Flame pulsation is an important characteristic of turbulent flames observed in pool fires. Current solid flame models inadequately predict the thermal radiation of pool fires, particularly the effects of flame pulsation. The thermal buckling behavior and fire resistance of a fixed-roof Q345 steel tank with a stepped thickness under a neighboring ethanol pool fire based on a flame pulsation model was numerically investigated. The influence of smoke generated by the combustion process which can reduce thermal radiation fluxes was taken into account. Geometric and material nonlinear analysis was used on finite element analysis. Nonlinear analyses were solved using an explicit dynamic algorithm. Results showed that losing the load-carrying capacity in a circumferential direction at the most heated area triggers thermal buckling of the target tank and that the observed buckling behavior is non-linear, and the deformation shapes are diagonally symmetric. Fire resistance (in terms of critical time (tcr)) of the target tank depends on the vertical location of the fire (Hf). When Hf increases from 3.56 to 17.82 m, tcr rises from 900 to 2710 s. Fire resistance decreases exponentially as burning tank diameter (Df) increases. When Df increases from 10 to 30 m, tcr reduces by about half. The fire resistance for the cylinder-cone combined flame is larger than that for the cylindrical flame. The cylindrical flame underestimates fire resistance of the target tank when flame pulsation is accounted for.
Reaction calorimetry has been widespread applied for thermokinetic analysis of chemical reactions in the context of thermal process safety and process development. Mixing heat of reactants may lead to deviation of reaction heat measured by reaction calorimetry as it can't be separated from the reaction heat, especially for a solvent-free reaction mixture. This work is devoted to evaluating the influence of mixing heat on determination of thermokinetic parameters for the esterification of propionic anhydride with 2-butanol in the presence of sulfuric acid. To this aim, excess molar enthalpies of reactant solution were measured using a Mettler-Toledo EasyMax102 calorimetric reactor at 298 K and 0.1 MPa for the quaternary system which may occur during the esterification of propionic anhydride with 2-butanol (production of propanoic acid and 2-butyl propionate). A model for the excess molar enthalpies of the reaction mixtures as a function of the molar composition has been developed, which mainly based on Redlich–Kister equations and NRTL model. The model, which shows a good agreement with experimental data, then has been adopted for the evaluation of the mixing heat, which may lead to accurate kinetic parameters, through the correction of reaction enthalpy for esterification of propionic anhydride with 2-butanol in a batch reactor. Furthermore, corrected results of maximum temperature of the synthesis reaction (MTSR) were able to be acquired and be applied in safety assessment.
Some fire and explosion incidents in the workplace including large chemical plants have occurred intermittently since 2011 in Japan. It is pointed out that insufficient risk assessment has been implemented in using hazardous materials and chemical reaction of treating chemical substances understanding insufficiently them. Especially small and medium enterprises (SMEs) cannot often devote adequate resources toward implementing risk assessment. Thus, it is expected that the scenarios related to unintended reactions and the examples of risk reduction measures for these scenarios are provided for SMEs. One of solutions is considered to show some typical scenarios related to some critical events (runaway reactions, fire and explosion due to chemical incompatibility, explosion of self-reactive materials etc.) as support measures for implementing risk assessment considering unintended reactions. To investigate the typical scenarios and the risk reduction measures to prevent the progression of these scenarios, the scenarios related to unintended reactions were analyzed by developing bow tie diagrams because bow tie diagrams can be easily visible on the relationship between the causes of the events and the consequences of concern, and the measures preventing the progress of the scenarios.
The bow tie diagrams related to runaway reactions were developed by reference to the literature about the causes and consequences of runaway reactions. Moreover, the risk reduction measures to prevent the progression of these developed scenarios were investigate using the developed bow tie diagrams. Furthermore, the incident cases known about the detail of these incidents were traced using the developed bow tie diagrams to investigate the adequacy of these diagrams. The results from these investigations will be presented at the congress. It is expected that the developed bow tie diagrams are helpful for SMEs with limited resources to study the appropriate risk reduction measures to prevent the progression of these scenarios.
Fugitive emissions are unavoidable releases that occur continuously throughout a refinery or chemical plant wherever there are connections or seals between the process fluids and the external environment. Daily exposure to such emissions may pose a serious threat to the health of the workers. Previous work has been carried out focusing on assessing the occupational health risk in chemical plants by means of indexes such as the inherent occupational health index and the integrated inherent safety index. However, the indexes are only a good proxy indicator of the source of potential occupational hazards (i.e. chemicals, process conditions and process equipment). Based on the Source-Path-Receptor (SPR) model, the exposure and thus the eventual health risk also depend on the path and receptor. Also, in actual chemical plants, there are usually controls and mitigation measures put in place to control hazards and these can be referred to as protection layers (PL). Hence, in order to assess and evaluate the occupational health risk in chemical plants due to fugitive emissions, a more holistic methodology is required. Therefore, a hybrid framework for assessing this occupational health risk was developed by integrating the concepts of Layers of Protection, Hierarchy of Control and Source-Path-Receptor model. The generic protection layers identified were classified according to traditional hierarchy of controls. At the source, the protection layer identified were hazard elimination/substitution, inherently safer design and engineering controls. Next, along the exposure path, maintenance and equipment reliability were the identified protection layers. Finally, at the receptor, worker exposure is linked with management systems, procedures, safety behaviour and culture. Therefore, the proposed methodology can be also used for benchmarking and performance tracking of occupational health risk in a chemical plant over time, as the methodology includes the time-varying parameters of plant maintenance, management system compliance, safety behaviour and culture.
Household products such as dishwasher products and multipurpose cleaners may contain specific chemical ingredients to meet the consumer needs. However, some of the ingredients may result in skin and respiratory irritation. Thus, a systematic methodology to estimate the extent of hazard and risk for consumers' exposure to the products is needed. In this work, an index-based methodology is presented to estimate the severity of the hazards and risks of the ingredients during the early stage of product design. Besides, such methodology can be used as initial screening tool to reduce the hazards and risk of household products. Higher score was assigned to the higher potential of hazard and risk, and vice versa. The allocation of score can reveal the different level of severity of hazard and risk. With the score, the hazardous ingredient in the product formulation can be identified. The hazard potential was determined based on hazard classification by the Global Harmonised System (GHS), commonly found in material safety data sheet (MSDS). Risk assessment was performed by considering the Margin of Exposure (MOE) and Risk Characterization Ratio (RCR). The no-observed-adverse-effect level (NOAEL) of chemical ingredients is used to derive the MOE. Meanwhile, RCR is calculated by comparing the value of derived no effect level (DNELs) to the estimated exposure concentration. To demonstrate the proposed methodology, the dermal and inhalation hazards as well as risks from ingredients used in formulation of liquid detergent were evaluated.