Preparation Of Super Fine Powder Fire Extinguishing Agent And The Study On The Ability To Extinguish Fire And Suppress Explosion

Halon extinguishing agent was widely used in the fire Fig.hting industry at home and abroad due to its high fire-fighting efficiency,low toxicity,no residue,wide application range,and good electrical insulation.However,it has been found to be severely damaged for the ozone layer and was gradually banned.As an excellent substitute for halon extinguishing agent,super fine powder fire extinguishing agent has received extensive attention from domestic and foreign researchers.Gas prevention and control is the top priority of coal mine safety production,and ammonium phosphate powder has a significant inhibitory effect on it.At the same time,it is noted that China has a huge amount of culture and catch of shellfish aquatic products,but the recycling rate of the remaining"shells"after eating is very low.Based on the above background,an attempt was made to prepare an super fine powder fire extinguishing agent containing shells,and to conduct an experimental study on its fire-extinguishing and explosion-inhibiting effectiveness.The prepared super fine powder fire extinguishing agent uses NH4H2PO4 as the main fire extinguishing component,(NH4)2SO4 and shells as fire extinguishing auxiliary materials,with mass fractions of 65%,10%,and 10%,respectively.At the same time,select methyl hydrogen silicone oil as the surface modification and silica as a hydrophobic agent,activated clay is used as a catalyst for surface modification,and talc powder,mica powder,and polycarboxylate water-reducing agent are added as additives to enhance the fluidity,anti-vibration,electrical properties of the ultrafine powder and reduce the moisture content.TQG-20 fluidized bed supersonic jet mill and"SHR-10A"high-speed mixer are used as the main equipment for ultra-fine and surface modification,respectively.super fine powder fire extinguishing agent with a90%particle size of 16.161μm was obtained.The bulk density,moisture content,moisture absorption rate,water repellency and penetration of the ultrafine dry powder fire extinguishing agent meet the requirements of GA578-2005"Super fine powder fire extinguishing agent".On the basis of previous research,a cubic test bench of 1m×1m×1m was built and used as an experimental device for testing the fire extinguishing effectiveness of the prepared super fine powder fire extinguishing agent.The experimental results show that the super fine powder fire extinguishing agent containing shells can effectively extinguish the n-heptane oil pool fire,and the fire extinguishing effect is weaker than the purchased ABC super fine powder fire extinguishing agent without shells,but compared with ordinary ABC powder extinguishing agent,the fire extinguishing time is shorter,the weight is less,and the flame temperature decreases faster.In addition,under 0.2MPa,the fire extinguishing time and the minimum fire extinguishing agent mass of the prepared super fine powder fire extinguishing agent containing shell components are 3.3s and 34.4g respectively.The average temperature drop rates of thermocouples 1,2,3,4,and 5 were 30.73°C/s,20.61°C/s,9.26°C/s,5.21°C/s,4.30°C/s,respectively.The explosion suppression performance of the prepared super fine powder fire extinguishing agent was tested using a 20L spherical explosion characteristics test device.The explosion pressure,the pressure rise rate,and the time to peak explosion pressure were the indicators of the explosion suppression performance.The experimental results show that the prepared super fine powder fire extinguishing agent can significantly inhibit 9.5%and 11%CH4.For 9.5%methane-air mixture,the best anti-explosion concentration of the prepared super fine powder fire extinguishing agent is 250g/m~3.At this concentration,the explosion pressure and the pressure rise rate can be reduced by 33.0%and 97.20%,respectively,and the time to peak explosion pressure can be prolonged by 729.2ms.For the 11.0%methane-air mixture,the optimal explosion suppression concentration of the prepared super fine powder fire extinguishing agent is 200g/m~3.At this concentration,the explosion pressure and the pressure rise rate can be reduced by 51.52%and 98.39%,respectively,and the time to peak explosion pressure can be prolonged by 1610.2ms.The use of waste shells in the production of super fine powder fire extinguishing agents provides a new preparation method for halon fire extinguishing agents and enriches the types of explosion suppressants used for gas control.For waste shells that are difficult to recycle,it has more practical significance.