Research on key designing parameters of destruction furnace for explosive waste

Transcription

1 Available online at Pocedia Envionental Sciences 16 (2012 ) The 7 th Intenational Confeence on Waste Manageent and Technology Reseach on key designing paaetes destuction funace fo explosive waste Gang An a,, Yinghui Wang a, Wei Li a, Jing Liu b a Dept. 4, Institute Cheical Defense, PLA, Beijing, China b Toop 66427, PLA, Beijing, China Abstact Explosive waste widely exists in people s lives, and bunout is an effective technology fo its disposal. A new destuction funace is pesented accoding to the chaacteistics explosive waste bunout, which could contol the destuction it. The analysis fo design equieent indicates the funace body and insulating laye ae the citical coponents. The thickness funace body which decides the enduance fo blast shock wave can be calculated though the dynaic coefficient ethod. Based on the axiu allowable adiation loss odel, the thickness insulation ateial is optiized. The design eets technical equieents and akes buning wok oe secue The Authos. Published by Elsevie B.V. Selection 2012 Selection and/o pee-eview and/o pee-eview unde esponsibility unde esponsibility Basel Convention Basel Convention Coodinating Coodinating Cente Cente fo Asia fo and Asia the and Pacific the Pacific and and National National Cente Cente Solid Solid Waste Waste Manageent, Manageent, Ministy Ministy Envionental Envionental Potection Potection China. China. Open access unde CC BY-NC-ND license. Keywods:destuction funace; thickness; explosive waste; insulated laye 1. Intoduction The explosive wastes ainly efe to the infeio-quality poducts, waste poducts and wastes explosive popety geneated duing the poduction, aketing and application explosives. A consideable volue explosive wastes ae poduced in vaious egions each yea doestic, and ight cause safety accidents and envionental pollution if ipopely disposed. Theefoe, the teatent explosive waste is a kind dangeous opeation. The exaple using otay ceent kiln fo hazadous waste teatent in doestic was fist seen in Yunnan [1]. Howeve, the hazadous wastes ae nueous and coplicated with diffeent shapes, sizes, stuctues and popeties. A significant featue explosive wastes is: when a apid cheical eaction occus and eleases a geat quantity heat and gas as esult Gang An, (1972-now), ale, associate pesso, Reseach inteests: explosive waste disposal Tel.: E-ail addess: @qq.co Selection and/o pee-eview unde esponsibility Basel Convention Coodinating Cente fo Asia and the Pacific and National Cente Solid Waste Manageent, Ministy Envionental Potection China Open access unde CC BY-NC-ND license. doi: /j.poenv

2 Gang An et al. / Pocedia Envionental Sciences 16 ( 2012 ) the action excitation enegy, the explosion pocess is had to contol. Thus, a special destuction funace which applies the buning ethod fo the teatent explosive wastes is designed in this pape. The device could constain the explosive enegy, slappes and pojectiles within an effective aea. It could filte hazadous gases and dust at the sae tie, thus potecting the safety suounding envionent, staff and devices. 2. Design equieent and basic stuctue destuction device The explosive wastes possess the basic featues explosives. When explosion is ignited, the ipact waves speading all aound would then poduce incident pessue when eeting with obstacles and change into tansient eflection pessue when eflected by obstacles; the eflected waves would spead back to the detonation point, and the ovepessue and wavefont velocity the eflected waves is lage than that incident wave [2]. Given that explosive wastes ae destoyed though the buning ethod, the following equieents fo the buning device ust be satisfied: it should be able to esist the explosive daage an equivalent weight 40gTNT; no plastic defoation shall be seen in the section the explosion cente the funace body; the opeation tepeatue in buning aea shall be constained within 300~500; no slappes fly out duing destuction; it should be convenient fo esidues cleaance, long-tie sevice and inteio space aintenance; insulating easue shall be adopted to pevent injuies caused by excessive tepeatue and theal adiation inside the funace. The buning device adopts cylindical vetical funace stuctue and is ainly constituted by the buning funace, cobustion device, slag dischage facility and cooling plant in the feeding outh, as shown in figue 1. The buning funace, constituted by uppe seal head, funace body and lowe seal head, is the site fo destoying the explosive wastes; the funace body is ade No.20 steel and extenally wapped with ock wool fo heat and sound insulation. The explosive wastes, which depend on fuels to heat up, could not be ignited without extenal enegy. The cobustion device is ainly applied to spit fie into the funace fo a cetain altitude, so that the inteio section the funace shall be coveed by the flae in the spitting position, thus causing the tepeatue inside the funace to ise to 350~500. The botto funace is coveed by built-in cone hoope which could open and close up; a locking latch shall be installed outside the slag eoval doo duing opeation to pevent it fo being blasted away. The slag eoval doo shall be ensued heetic so that it could be opened again fo slag cleaance when the buning pocess finishes. The cooling plant in feeding outh adopts stuctue ciculating wate jacket. Wate cooling jacket is installed in slide section, and it is also extenally equipped with a ciculating wate tank. The wate puped would ente into the wate cooling jacket; the effluent would ente into the wate tank fo ecycling. Relying on the elatively lage volue wate tank, it is ensued that the tepeatue ecycling wate is kept below 80, and the intenal tepeatue the slide be kept below 100. Given that the explosive wastes shall not explode inside the slide, the secuity feeding outh is theefoe guaanteed.

3 204 Gang An et al. / Pocedia Envionental Sciences 16 ( 2012 ) Uppe seal head 2 Funace body 3 Suppot 4 Maintenance doo 5 Lowe seal head 6 Cone hoope 7 Rapid slag eoval doo 8 Soke outlet 9 Filte net 10 Bune outh 11 Slide 12 Wate cooling jacket 13 Wate pup 14 Recycling wate tank Fig. 1. scheatics destuction funace The key in the design cylindical buning funace lies in: calculating the thickness funace body in accodance with the explosion equivalence and the intenal space specified in the design; selecting suitable insulating ateial and calculating elevant thickness based on the insulating equieent funace body. 3. Thickness Calculation Funace Body Fo the cylindical R buning funace, the section the explosion cente funace body beas the axiu explosive ipact load, thus, the key in the oveall design funace body lies in ensuing the echanical safety elevant pat. Fo this eason, the design wall thickness is especially piay when the stuctue, ateial and adius funace body have been deteined. The wall thickness is equied to be designedly calculated based on the known adius ( R ) and ateial (20R) funace body unde the effect explosive wastes ( W 0. 04kg TNT) Reflected ovepessue Fo the buning funace, theoetically it is assued that the explosive wastes explode at the cente the funace body with a popotional distance R : Q i Q T In the foula, Q Q R R 3 W (1) i T the atio between the explosion heat explosives and that TNT. R kg When calculating the incident pessue p, the J.Henych foula shall be adopted when it is egaded as the condition spheical explosives exploding in the ai: When R ~ 10 p R R R (2) In the foula, p the peak value ipact pessue, MPa.

4 Gang An et al. / Pocedia Envionental Sciences 16 ( 2012 ) In accodance with the calculation, when eflected ovepessue ipact wave acts on the inne wall the buning funace (consideed as acting fowad on igid wall), the peak value eflected ovepessue p is calculated by the following foula 3: p p 6 p p 7 p (3) In the foula, p 0 standad atospheic pessue, MPa The dynaic coefficient The dynaic coefficient ethod based on the theoy coposite echanics is eployed, and the equivalent load ode action is consideed as tiangle wave [3]. By obtaining the equivalent action tie t and the natual vibation fequency buning funace though siultaneously consideing foulas 4, 5 and 6, the dynaic coefficient C d is finally calculated out: In accodance with the following foula: t R (4) Q T E gr (5) C d tan t t (6) In the foula, epiical coefficient, 0. 5 fo cylindical funace body; Q T explosion heat unit ass TNT; E Young odulus, MPa ; ateial density, 3.3. Thickness 3 kg. Unde theoetical design tepeatue, the thickness the inne containe funace body is calculated by national standad unde static pessue condition: d t d p C R 2 p C (7) In the foula, t allowable stess funace ateial unde design tepeatue, MPa ; welded joint coefficient. Fo the calculation the design thickness the funace body, the thickness deviation, coosion allowance and pocess thickness eduction the steel ust be taken into consideation. Thus, the design thickness d is calculated by the foula: (8) d n In the foula, n edundant thickness,. Afte calculation and ound-f, d 30 is obtained. 4. Design insulating laye The funace body is coated with an insulating laye outside to educe the heat loss inside the funace. As indicated by design expeience, ock wool is featued high econoical efficiency and pefeed as insulating ateial. Having confied the insulating ateial, the insulating effect is deteined by the

5 206 Gang An et al. / Pocedia Envionental Sciences 16 ( 2012 ) thickness insulating laye. In doestic, econoic thickness calculation ethod is usually eployed to obtain optial thickness the insulating laye. But, given the liited suface the funace body itself, in copaison to the consuption pipeline, ateials ae consued in uch salle volue; eanwhile, anothe ipotant pupose insulation is to potect the opeating pesonnel fo being affected by adiation heat. Theefoe, the "axiu allowable adiation loss ethod" is eployed to calculate the thickness the insulating laye g [4] Calculating the thickness insulating laye g The buning funace is coposited funace body, insulating laye and shell. Given that both funace body and shell ae 20R, they ae consideed as non-insulating ateials theoetically (tepeatue funace body T 500 C ; tepeatue shell equal to oo tepeatue T a 30 C ). Theefoe, by siultaneously consideing foulas 9 and 10: D o Do Di 2T Ta Kq ln (9) E gr (10) 2 W C ; In the foula, coefficient heat conductivity insulating ateial, K safety coefficient; q axiu allowable adiation loss; j calculated thickness insulating laye,. Afte ound-f, the design thickness the insulating laye is obtained 4.2. Veifying the suface tepeatue g 130. The suface tepeatue insulating laye T s is veified by: T q a T (11) s a The calculated T s 85 C is the tepeatue which could be endued by the opeating pesonnel afte caying out potective easues. 5. Conclusion By eploying the above ethod, the explosive buning device has been successfully developed and tested by seveal explosive expeients. It is poved that the explosive buning device designed by the above ethod is eliable. What needs special attention is that: TNT is used in the expeient, so only the effect ipact wave is consideed in the design. Howeve, given that eal explosive wastes also have etal packing shells, so the ipact activities fagents should also be taken into consideation when calculating the destuctional fos the funace body. It should be popely consideed when veifying the stength the funace body. Refeences [1] Wu Xueyong,Zhang Tao,Gao Yongqiong.Discussion on Pocess Techniques fo Yunnan to Use Ceent Rotay Kiln Teating Hazadous Waste[J]. Yunnan Metallugy;2008,37(5):58-69.

6 Gang An et al. / Pocedia Envionental Sciences 16 ( 2012 ) [2] Bake W E.The elastic-plastic esponse thin spheical shells to intenal blast loading[j]. ASME Jounal Applied Mechanics,1960,27(1): [3] Hu Bayi, Bai Jinsong, Liu Dain. The Engineeing Design Method Explosion-Containent Vessel and Its Application[J]. Pessue Vessel Technology;2000, 17(02): [4] Yuan Baotong, Li Maojnn. Application Econoic Thickness Calculation To Deteine The Insulations Equipents and Pipes[J].Petoleu Pocessing and Petocheicals;1996, 27(07):36-39.