Research On Safety Diagnosis And Improvement Of Combustible Dust Risk Of CMC Process System

In recent years,dust explosion accidents have frequently happened,and the nature of accidents have become more and more serious.As the classification of labor in modern industry becomes more and more fine and the products become more and more refined,some fine chemical companies also have a large number of raw materials and products of fine powder and ultrafine powder,which also brings a lot of dust risk to enterprises and society.It is of great practical significance to effectively assess the risk of dust in enterprises,recommend preventive measures,and reduce the consequence impacts caused by dust risks to enterprises and society.In this paper,the sodium carboxymethyl cellulose?CMC?of Company A was selected as the research object of dust risk.By comparing different risk analysis methods,the risk analysis method?CDA?of flammable dust was selected as the risk analysis method of this paper.CDA is a A specific method for the assessment of dust risk identification,the specific work are as follows:?1?By analyzing the basic mechanism of CMC dust fire explosion risk,affecting the ignition factors of CMC dust fire explosion,such as static electricity,hot surface,friction,etc.,CMC dust fire explosion forms,such as initial explosion,propagation explosion,secondary explosion and flash fire,etc.And prevention and control measures,such as explosion suppression measures,explosion-proof measures,etc.Provide a theoretical basis for the next step of CDA assessment.?2?4 typical process unit dry fluidized bed units,crushing units,air mixing units and packaging units involved in dust risk in A plant are selected,and 23 deviations that may occur in 4 process units using CDA analysis are identified.Then,a risk assessment is performed on a pair of 23 scenarios,and the actual risk level interval is evaluated based on the design state and the existing IPL presence.?3?According to the actual risk level interval of the 23 deviation scenarios obtained by the CDA analysis method,the protection measures and improvement guidelines are proposed one by one,and the risk level is reduced based on the action interval selected.Studies have shown that since CMC is a fine powder solid,in the four process units selected in this paper,there are mainly CMC solid powders which have been initially dried or completely dried,and the system also needs air as a heating medium or mixed media,so it is easy to form a dust explosion cloud,therefor there is a high risk of dust.Through the use of CDA analysis,it is estimated that there are risks such as dust fire,primary dust explosion,propagating explosion and secondary explosion in these process sections.The highest accident probability is 10⁰/a,and a series of measures such as:prevent the generation of static charge and use explosion-proof electrical equipment;increase the explosion-proof and explosion-proof system;for individual equipment,it may need to enhance its design to withstand the deformation energy due to dust explosion;and strengthen the on-site cleaning practice to reduce dust cloud preventive measures such as formation.Reduce the risk of occurrence to at least 10^-4/a,or even 10^-6/a.Therefore,the dust risk in the process of the factory is effectively controlled.