Inherent Safety - Summary

Designs that avoid the need for hazardous materials or use less of them or use them at lower temperatures and pressures or dilute them with inert materials will be inherently safe and will not require elaborate safety systems. 

When synthesizing a process, the occurrence of flammable gas mixtures should be avoided, rather than relying on the elimination of sources of ignition. 

One of the principal approaches to making a process inherently safe is to limit the inventory of hazardous material. The inventories to be avoided most of all are flashing flammable or toxic liquids, that is, liquids under pressure above their atmospheric boiling points. 

The following changes should be considered to improve safety1-3  

When synthesizing a flowsheet, the designer should consider carefully the problems associated with operation under extreme conditions. Attenuation will result in a safer plant, providing the attenuation does not increase the inventory of hazardous material. 

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Lawrence (1996) summarized the answers of the experts and calculated the total scores for each parameter. According to this summary the most important parameters for inherent safety were inventory and toxicity. Other important factors were, in this order, chemical stability, temperature, pressure, flammability and explosiveness, which were considered to be essential by all experts. Also flash points and side reactions were quite important. 

In summary, the accidents main reason is closely related to human behavior. From macro-viewpoint, if the behaviors of corporate decision-making layer, management layer, operate layer are correct if equipments, machines and tools can achieve inherent safety through the scientific and technical personnel research and safety technical personnel operate standard if environment conforms to safety standards, the accident would not have happened. So, coal mine accidents human error mechanism model is established, human error is the primary reason for coal mine incidents. 

In Eqs. [6.14] and [6.15] Me is the flow rate of chemical C Icj is the score of the chemical inherent safety subindex of chemical C Np is the number of equipment P and Ipi is the score of the process inherent safety subindex of equipment P. Again the dry grind process is found to be superior. In summary, it is observed that the dry grind process is superior to the wet milling process for aU three sustainability measures. 

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