Model for improving the reliability of safety systems in the technological processing of hazardous industries

Abstract

The problem of safety provisioning in technological processes, which aims the reducing the probability of accidents is considered. Classification of technological process states from the point of view of accident prevention system is offered. The set of such states consists of: normal functioning, pre-emergency, emergency and accident. The state of normal functioning and pre-emergency state assume the absence of irreversible changes in the technological processes. It is considered the case when the operator has to form some management actions which are aimed to stabilize the process, when the process is in the pre-accident state. It is shown an example of a data flow diagram, which includes also the human operator, the tracking system, and the system of manual and automatic control in additional to the standard components of such systems. By using the data flow diagram, it is defined the sequence of stages which occur when the process in transferred from the pre-emergency states to the state of normal operation. A method for assessing the possibility of transferring a technological process from a pre-emergency state to a normal operating in proposed. This method consists in estimating the time relation between the available and the necessary for stabilization of the system. The time required for stabilization consists of the time delay of the measuring device, the latency of the operator and the response time of the actuator. The delay time of the measuring device and the response time of the actuator are determined by the conditions of the technological process. The model for estimating the latency of the person is based on the law “force-time” is developed. A study of the boundary cases of the formula for estimating the available and the necessary time is carried out. Stimulation modelling is conducted, which results are used to estimating the ways of optimizing the technological process in order to improve the reliability of the accident prevention system.