Document K6b8o72RX8Jm9ek0JdEJw1mkN

HYDRAZINE continued I: fteflfoi il Oiyiea Witt Hytfnrfne II: Corrosion Teif--Irtm-Conlenl Iraroaso (raj re)!' HYDRAZINE CHEMICAL AND HANDLING PROPERTIES Swell** Mrtfr8li %, netted In nmnw at: rotp, tim, I ng Mil 8.1 me MiT I g f F 4 Without . dtp C mtoirtt* oi MoCIi fliMoCfi ai ft S0< 0.7 Mp Mm eSSflto* 7J.J 9)5 itl )).) 11.0 41.1 11.9 *7.1 41.1 19.4 NJ 77.S JI.S 51.0 1.0 94.) tt.t r;.e 45.7 47.0 CwWuMfo CocMootolo Cowf4f ConTMtalt 4 fto**, vJltout A 04 A 10 4 04 9 hydro- ... -ojMjr/t.fie.A- No50/"f Mo*SO/< slito Ay4>oit 0.Q1 0.01 041 004 o.oi 0.01 t.J 0.01 9.1 0.11 14.5 ro.o SgfrllE HYDRATE (85%) MiK. - H0 50.0) Trt(t4 & a*4 fw"<} to**" 54% NiHo HJ*t ct-- 54.4% 0.01% Catortoti, m*Mb Itsvie I.J* at C C***toto>r tactkto't* vet*i MS m*rSMl 9.9 <1% mIHm U C) todvitrlel Utltltyt Hrerxil** bet toog bm Mcogaftoe ot **rMt(to (Aim- teal m4 In InSuitriol otillty bet, Io fiteoy cbms, b** *tobl)]tooS It I* * r*4oclnp ost to* both tocr^anlc 0*4 egonte cAcmicoto. ( aOJUlf f* tadata *Mtal salto or ild*f to tbo tot* mtol li being uiIIImS, .tor it*"*)*. W s*oto *)tov* oo glei*, ototoH bo* No*Uc* HfDRAZINI HYDRATE (100%) Chemical Htmttto: rormito **tgbf: M.H, - H*0 50.05 |5&i: 1.4$ canllptlHt Ol 1$ C Qrod*: Ttcbnlcal KK* w-<: 1.414 ,, 75.1 drm c* at 15 C Ml* ocllvs UgrctfltnO: Trolcol OMlyilt: 44%. to(H 44.1% Mlnvi 57 C Cl-- 0.41% timum pH cottdiiiono for (he hydrazinelo-oiygen reaction in feedwater, namely 8.5 io 9.0. Feed temperature at the In jection poind waa 180 to 190 F. Hydra zine injection look place from Monday to Friday only, oo week-end operation of the bolJero brought the system back to normal conditions, providing reference data for the reat of the week. Further, injection was made only during the teaming hours of the boilers, roughly some 16 hours a day. Test o: 700-800% excess hydrazlnei Hydrazine was injected for one week to give 0.5 to 0-6 ppm In the'feed. This definitely scavenged by hydrazine and, what is more, that oxygen and hydra zine do not coexist in solution. When hydrazine appeared at the preinjection point, oxygen contents of condensed steam, feed-pump water and prelnjec(ion water ail ran about 0.005 mi per ), considered the threshold value of the oxygen method of testing. Ammonia in the system did not rapidly increase, as was thought possible, but began ao rise after two or three days' operation, be coming as high as 0.9 ppm in the surge tank by the fifth day. A sample of con densed steam, taken when the boiler ihe pH figure, ihom that that be correlated with ammonia centem; also that carbon dioxide ingress matf have been playing a variable and aetHjj role. This was strikingly borne out if. the end of the aecond week's operating that ft the end of Test b, when measurements were made on the iieso^ after the boiler was banked. Coincident with a riao in steam, conductivity *a(j) ammonia to 8.0 units and 0.44 ppm ri pectlvely. pH dropped to 4.8 sevenj? hours after the boiler came off load^ Some unevaporated, undeaerated makerup water, containing carbon dioxIde'V 119.1 C 19) r, mlS4 TS4 1, w*n-cvp <Mt%*d Star* I* e (Ml am; Stop cintelMr HgMlY cl#**e vim aat to lim4loto (M. AnM cwtoct with wlStotog o*Ato AIHimsS Sydiaito* bydratv (15%) t parttcalorty rttom- mtadtd tor toAattrtof ** Occam at lit lawtr caacvntrs. lie* l KySraiiiw, 1t>* totoltag pf(*tl*M mv **U b* t*tldar*d IS* tama at that* apphtng I* SjWraslA# kyeroto (I04%| and aahyd/Mt hydtoiliw I* tfc* Siilg* at Indurtrlal Met* igulpm**! * b*dling antiytfr*in Syeraito*, 0*4,14* fcpSracto* SySraW* (Salk IM% ond 15%), itaUtou >ttl 104 at )47, fxSrleotoS Sy tolto-ge **<rfto*. to utooHr uftvito. 0M-4to4 itMl It (OtlsNOary, but anwsporWO oktt I* ri(to- *Mto4 tor tore* MvIsitiMt bcanu.tf Wi svrUbllliy *t brnkap* Appcorooco a*S form: RoaoSi o*r Saltan: Utobtlihi: pH-. VlKotltys Sartaco tooston: Rctrectlv* lo4i: Mrlltos poi*: RotUos Rotit: ftoUi saint: fir* pal*'! Coiortoti, mbit* Uealrf S.ll at IS C C*tototo mloctbl* In motor snS ontttanol 9.9 (!% Mlatlon at IS C) 1.5 (tnllpoUat at 15 C T4.1 dyai cm at IS C I.41S4 *B 51.7 C tIO.t C 14) r (71.1 C)--*S*n->P OMtiad 144 t (74A C>~sn-<o matbaS Tb* Stosclk* *1 bydrotln* hySrat* (100%) an limitar to (ban *1 anbydraar feydracla*, dlftortog m illgbriy that tb* oam* landtinp m*1h*4i and pncanttoM or* S*"rally osnilcabl* corresponded to 800-1000% excess hy" dfoxine based on the theoretical oxygen requirements. Almost immediately hydrazine ap peared at the feed pump and after a day or two in the surge tank and de aerator, showing it (]) is reasonably ceased steaming on Friday, showed ammonia as high ai 1.1 ppm. Conductiv ity of the condensed steam increased to 6-7 emits as the ammonia increased. Tes) fc; 150-200% excess hydrazine. When ammonia in the system dropped back to normal, oxygen teats, carried out was believed to have entered the boilers' on shutting down. J Water samples went to the laboratory^ to confirm ammonia determination*, lad rcL io test for albumenold ammonia. Asex-^* peeled, albumenold ammonia was nil or very small. PbSiwtlr' ,C**tolWTU C*m<nfrta( St el (440 tb. Ml) )0 sal (140 lb. Ml) Sta>tow-*tMl Omibii, wturaobt* Warning tobt< WM1 labal {eamihtt UanM} AIm awltotl* to l-plnt botitc* AvoildbltHy-. C*m<n*rctol *onnll||*i CaaNitnar*: <5 gal <440 tb, Ml) )0 gal |140 lb. act) Induttotal Ulllttyi f# dctalti canrtog tb* alflltv at feydrasfa*, nfir to tooting and*r Sl% brdrscln* hydroto table (2) can withstand the 185-F tem before injecting hydrazine, showed a low Physical appearance of the boiler perature, existing in the 30-ft length of oxygen level in the steam, despite a waters, after hydrazine injection, was feed main (3) can pass through the normal feodwater oxygen, indicating significant. Normally, suspended nutter m deaerator. No hydrazine could be found in the tttom condensate. This occur rence of hydraxlne, at all pointa except the steam sample, made analyiis more difficult. It took several days to devise, cheek and pronounce aatitfactory the that oxidation was occurring within the hoihr or feed mein, or somewhere after the food pump. Possibly it was oxida tion of lower iron oxides produced dur ing the hydrazine-injection period. Concentration of hydrazine was re from these boiler waters is large in qusn-' thy, confining mainly of eatlly hhenbla', red ferric oxide. During hydrazine treat-^ ment, the quantity of sludge appeared!? leas, and the color, while still red, wai'l leas intense. Further, it was very finely, they may influence subsequent tests Jit be considered. For example, it is jupotilhle that hydrazine can behave In j^V^boiler plant in threo ways: (1) Pri- ^osrily it will scavenge free oxygen, giv- a decomposition product its use docs not add impurities to the system. Eco nomically, It compares very favorably with sulfite Injection. Treatment Costs. This statement can 0.540 = 0.533 lb hydrazine hydrate per day. Cost per boiler: 0.533 lb at $1.55 per lb Is $0.83 per day. Date for thi English report supplied by fFhiffen & Sens, London, England. - modifications required in the analytical technique for the determination of oxy gen and ammonia in the pretence of hydrazine. It requires very great accu racy io lest for oxygen of .01 to .02 ppm or leu, and all traces of hydrazine muat be removed. The technique finally adopted, wher ever.hydrazine showed in the sample, was to (If reduce rapidly the pH of the sample immediately after it had been taken, thus fixing the hydrazine (2) de termine the ammonia in the usual way. Oxygen was determined by the electro metric method, after first removing the hydrazine by oxidation with permanganste. The hydrazine in the injection solu tion waa determined by direct titration duced then for Test b's run to shout 0.15 ppm in the feed as against Test a's 0.5 to 0.6 ppm. Quite different re sults developed. No hydrazine reeirculaiion occurred through the surge de aerator system, nor waa any significant rite in ammonia concentration detected, although, os hat been pointed out, alight decomposition into ammonia might be masked hy a generally high ammonia content normally present in the system at that time. A still further difference was-that hydrazine and substantial oxy gen concentration* were obtained to gether- at the feed pump, probably because the greatly reduced hydrazine excess did not permit the chemical re action to go to completion at this point. Oxygen content of the steam waa divided and almost impossible to filter. The hydrazine may have some reducing ^ jing,water and nitrogen as products. (2) -fiRzceas hydrazine will then reduce metai- effect in the boiler or, more probably, (here was an absence of oxygen within [Aliejoiides, giving the same products as $$?!.) (3) In absence of oxygen or ox- the boiler, confirming the finding that catalytic or thermal deeompoiitlon oxygen removal could still take plsco :(t:Ji*lie$ place with the formation of am- within the boiler plant when hydrazine j if'^w1iia and nitrogen. injection ceased. |Ml<i/rActio (1) la the desirable one, while Summery. This three weeks1 trial of |3-i!(2J must occur, especially In old plant hydrazine as an oxygen scavenger led to ''(jYhtre much oxide scale exists. Action these first indication*: (1) Hydrazine,is on excellent oxygen scavenger- (2) I>;'*(1) may account for various joint leaks, I^Yctg, lhxi occurred in the feed system of When equilibrium conditions are estab 'iftest eases (1) and (2), and also for the lished, hydrazine and oxygen do not , - '^ster phenomenon. appear to exist together in solution. (3) 4.,iVV^.Aetion (3), definitely undesirable, Hydrazine proves more stable than had K^niy occur If action {2) reaches equl- been supposed, and does not inline- 'ij^libnum, when further excess hydraxine diolcly decompose at temperatures of ,*j -^decomposes into ammonia. Ammonia 18S to 190 F. (4) Main decomposition -tal v ;!*PP*rance in the trials during the be amplified by an example from Amer ican practico. In an Industrial power pltnt having nine boilers of 600-piig- design working pressure, where.sodium sulfite is used as the deoiygenatlng agent, cost for sodium sulfite averages 11 per day per boiler. Calculate equivalent costs lor 85% hydrazine hydrate at its present priee of fl.55 per lb (one to nine 240-lb drums f.o.b. Niagara Fells, New York) as follows: Ppm Oxygen content of water 0.08 Equivalent hydrazine (N*H<) Hydraxine residual desired 0.08 0.04 0.12 GERMAN REPORT Degassing Proms. There is a deft- nite demand for a chemical degassing agent not afleoied by the disadvantages of sulfite. In recent years the industrial production of hydraxine points the way to a solution. Hydrazlnd combines with oxygen dissolved in water In accordance with (he equation: N,f|4 plus 09 equals Ns plus 2 HjO, Thus two perfectly harmless compounds, nitrogen and water, form 32 grama of hydrazine, being ablo theoretically to hind 32 grams of oxygen, while 252 grams of sulfite are required lor 32 grams of oxygen. Hydraxine, available bn the market as a hydrate and added to feedwater in that form, ts highly alkaline and, hence, with potassium iodate in acid solution, again reduced (a virtually zero, showing product of the excess hydrazine used vSI )--,'l|tavy injection of hydrazine supports Since 100,000 lb of water requires can form salt* with acids and also, of In the water after injection by the Pesos end Petit method employing pared!molhyl-amlno-benzaldehyde reagent. the injection of only 150-200% eieesa material was apparently satisfactory. Other Tests. Up to now, we've made is not ammonie under tho operotiog "j4jll^* view. conditions. Ammonia, however, forms I^CHydratine is valuable for feedwater unitder ceerrttoain ci.r.cu_m__s_ta_nc_e_s js,yrc*(mem, and provided ammonia is not 0.012 lb N,H*. 0.012 X 24 equal 0.288 1b N|H* per day. Now 85% hydrazine hydrate contains 54% N3H4, or 0.288 course, with any C03 that might still be present. Thus, if a certain excess la pres- (Continued on page 212) Results Indicated that oxygen was no reference to pH value. A study of Possible hydrazine after effects, and ^NOVemse* 1953 ENGINEERING AND MANAGEMENT SECTION ENGINEERING AND MANAGEMENT SECTION POWfl