《化学品安全与法则 - 4》由会员分享，可在线阅读，更多相关《化学品安全与法则 - 4（88页珍藏版）》请在金锄头文库上搜索。
1、Page 1大连理工大学精细化工国家重点实验室大连理工大学精细化工国家重点实验室大连理工大学精细化工国家重点实验室大连理工大学精细化工国家重点实验室 State Key Laboratory of Fine Chemicals, Dalian University of Technology化学品安全与法则化学品安全与法则化学品安全与法则化学品安全与法则授课教师授课教师授课教师授课教师：包明包明包明包明，冯秀娟冯秀娟冯秀娟冯秀娟联系方式联系方式联系方式联系方式：0411-84986181E-mail: Page 2目目目目 录录录录3 1爆炸事故案例简介爆炸事故案例简介爆炸事故案例简介爆炸事
2、故案例简介3 2粉尘爆炸与防护粉尘爆炸与防护粉尘爆炸与防护粉尘爆炸与防护3 3气相爆炸与防护气相爆炸与防护气相爆炸与防护气相爆炸与防护目目目目 录录录录Page 3?Brief introduction of the accident,?Bethune Point WWTP, in Daytona Beach, Florida, US?Methanol as the organic nutrient for the bacteria?January 11, 2006?Methanol tank explosion and fire?Ignited by a cutting torch? 3,0
3、00 gallons of methanol released and burned?Two workers died?One worker severely injuredSolvent Explosion ?A breath valve shall be installed.Page 9?Maize dust explosion in Metz, France?Explosions do not have to be devastating to harm peopleDust Explosion_FrancePage 10Dust Explosion_China?2011-05-20,
4、富士康车间爆炸, 成都?2010-02-24, 秦皇岛利华淀粉厂爆炸Page 11?What are the three things we need for a fire?Fuel?Heat/Ignition source?Oxygen (Usually air)Fire TrianglePage 12?Additional two elements for an explosion? ?Mixing?ConfinementConditons for ExplosionPage 13?How much pressure kill YOU?Vapour phase explosion?Dust
5、 explosion ?Condensed phase explosion?Value may double in O2atmospheresExplosion Severity1.5 bar6 to 8 bar8 to 10 bar1000 barPage 14Dust explosion Prevention ?In a dust explosion, fuel and oxidant are well mixedPage 16?Explosible or not ?Explosible limits (LEL either low, medium or high3,3,33,2,32,3
6、,23,3,22,2,32,3,33,3,13,2,22,3,12,2,11,2,21,3,32,2,23,2,13,1,32,3,11,2,31,3,21,1,31,2,12,1,31,1,22,1,13,1,11,1,12,1,21,3,1Low riskMedium riskHigh riskDust classificationPage 341.Kstvalue = 331bar m/s Classification 32.Minimum ignition energy = 10mJ Classification 23.Powder resistivity 109 ohm Classi
7、fication 34.Number for assessing material risk is “3,2,3”5.Therefore the material risk is “High”.Dust classification?An examplePage 35?The operational risk is related to how a powder is being processed and handled.?It is a measure of the potential for an operation to generate:?a combustible dust clo
8、ud;?a heat or ignition source;?a static charge on a solid.Operational riskPage 36?Powder addition (removal) from vessels?Into empty vessels?Into vessels containing flammable solvent?Containment of dust / vapor whilst transferring?Pneumatic transfer into vessels?Pneumatic transfer between plant proce
9、ssing vessels?Mixing powders?Dryers?Particle size reduction (sieving milling, de-lumping)?Dust separation (cyclones / filters)Typical operationPage 37?Basic level: for handling all explosible dusts, “good housekeeping” is always required. ?to avoid of dust layers?to prevent secondary dust explosions
10、 (most dangerous)?no electrical ignition sourcesDefining Basis of Safety - PreventativePage 38?Level 1: control of ignition sources?basic level plus?earthing and bonding of equipment?minimizing electrostatic ignition sources ?earthing people (not a requirement if MIE 50 mJ)?use earthed scoops / soli
11、ds movement systems (not a requirement if MIE 50 mJ)Defining Basis of Safety - PreventativePage 39?Level 1: control of ignition sourcesDefining Basis of Safety - PreventativePage 40?Level 2: limiting dust ?if the system is open or closed and allows access to ignition sources;?moving machinery which
12、could generate a static charge or allow energy to enter the system through friction, e.g. agitators;?high transfer rates increasing the chance of a static charge e.g. centrifuges, pumping, operating at high velocities;Rating the risk OperationsPage 68Rating the risk OperationsOperationRatingFiltrati
13、onopen boxcentrifugeHighVery HighReactionflammable gas emissionspresence of oxidisersopening reactorHighHighMediumRating risk from OperationsPage 69PROCESS RATING+) In general, Level 5 represents an unacceptable level of risk and expert advice should be sought.(*) Recommending inerting.PROCESS RATIN
14、G5(+)5(+)43?Flammable Gases5(+)4332Very High Risk4322(*)1High Risk43211Standard Risk22111Low Risk11111Very Low RiskVery High Risk (level)High Risk (level)Medium Risk (level)Low Risk (level)Very Low Risk (level)MATERIAL RATINGPROCESS RATING5(+)5(+)43?Flammable Gases5(+)4332Very High Risk4322(*)1High
15、Risk43211Standard Risk22111Low Risk11111Very Low RiskVery High Risk (level)High Risk (level)Medium Risk (level)Low Risk (level)Very Low Risk (level)MATERIAL RATINGPage 70Page 71?Level 1: to eliminate potential sources of ignition through equipment design and operational procedures.?bonding and earth
16、ing of equipment and personnel;?anti-static protection;?avoidance of low-conducting liners inside to reduce the chances of generating an electrostatic charge;?a weak roof on a storage vessel;?attention to flow rates (normally 7ms-1);?avoiding splash filling.Defining Basis of SafetyPage 72?In general, control measures shall be considered for the followings:?No naked flames?Bonding and earthing?Antistat
