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Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
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Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
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Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
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Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
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Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 9
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 10
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 11
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 12
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 13
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 14
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 15
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 16
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 17
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 18
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 19
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 20
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 21
Suggested Citation:"THE STEEL INDUSTRY." National Research Council. 1987. Increasing Energy Efficiency in the Steel and Petrochemical Industries Through Waste Recycling and Reduction. Washington, DC: The National Academies Press. doi: 10.17226/19174.
×
Page 22

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6 res i s tance and high strength-to-we ight rat ios , have also increased produc t ion in recent years. In 1976 the Comm i t tee on Technology of the International I ron and S te e l Ins t i tute (I I S I) pub l i shed a review of energy us e in the iron and s te e l indus try . Th i s work was based on an analys i s of mode l plants, and thus i t e s tab l i shed the "ideal" s c enar io for energy us e in s tee lmaking. In 1982 an updated s tudy (2) was publi she d by I I S I bas e d on analy s e s of hypothe tical "re ference" plants that would permi t operators t o compare the ir performance with the re ference plants. The re ference p l ants were an integrated fac il i ty (blas t furnace-bas ic oxygen furnace) and two ele c tr i c a r c furnace s ( one fully sc rap fe d) that were us ed as the bas i s for compar i son. In addit ion to ident i fying technically proven i tems that would be cons idered commerc ial ly viable , the report also ident i fied a number of "technically unproven" sys tems that could further improve energy u t i l izat ion w i th economically at trac t ive rate s of re turn. Figure s 1 and 2 show the configurat ion of the inte grated and e lectric arc re ference plants. Integrated produc tion of raw s te e l i s based on sme l t ing ore in the b las t furnace us ing coke as the pr imary fue l and then refining the s te e l in bas ic oxygen ve s s els , with a few remaining open hearths s t i l l in operation. In 1985 about 66 percent of all dome s t ic raw s teel was produce d in integrate d fac i l i t i e s so de fine d. Th i s percentage is expected to de crease by 1995 to about 60 percent as ex i s t ing open hearths are re tired and replaced , mos tly by ele c tr i c furnac e s us ing s c rap as the ir pr inc ipal source of iron uni ts. Ele c tr i c arc furnace ( EAF) produc t ion ut i l izes ele c t r i c al energy to both me l t s c rap and to refine the liquid s te e l. In recent years oxy-fue l burne rs have been us ed to supplement the ele c trical energy. The trend has also been toward me l t ing in one ve s s el and refining in a s e cond ve s s e l , us ing ele c tr ical energy as the pr imary heat source. Elec tric arc furnace produc t ion is us ed exclus ively in minim i l l s and is the predominant me thod of produc t ion for specialty s te elmakers. Figure 3 shows the ene rgy consump t ion for the s e plants. Pr imary energy los s e s for the integrated refe renc e plant are shown in Table 1. The overall energy consump t ion for th i s re ference plant i s 4597 Mcal/tcs. The Office of Indus trial Programs has sponsored a number of projec t s relat ing t o energy us e b y the iron and s teel indus try. The s e projects and the ir goals are summ a rized in Table 2. Cons iderable progr e s s has been made toward the deve lopment of a base of te chnology and op t ions for improved energy ut ilizat ion by the indus try. As cap i tal improvements are be ing made in ex i s t ing plants, some of the s e changes are be ing adop ted. Better energy ut ilizat ion by i t s elf is not suff i c i ent to enhanc e the internat ional comp e t i t ivene s s of the iron and s teel indus try.

7 .. . ., ...... , ···" la-1 •···· ...,._., Ccllce ..... 478 ... •-.pellet ..u. 70110 I, 1St Cateell HIII-I..Ur. 71'& 1,700 - .......... , 1,100 ..... , (4, 100 ....... 100 ..._., 11111'8tloJft 1,111 t-t•rr .au .... ,.. , 704 ....... , I, "7 .,._.aal . . ... ... .... . .. ... 11 ....... radl I, 011 laect-•1 CJI.I'&IIIIIell819 .... al .............-., 7. . ..... ........ .. ... u a.'" IDald .au ....... , 100 ltlelllllllytlc .. .... "'...._, Sll ltlect..a,u., ........ , FIGURE 1 Outl ine confi gurat ion of the integrated re ference plan t . Output (x 103 t/y) Output (x 103 t/y) Confiauratlon 1 Confiauration 2 .... . ....... . . : Scrap ! .... • • • • • : Scrap : i i • • • • • • • • • • • • : i : ... l···............... . . . .. . . ! DKI l • • • • • • • • • • • • • • • • • • • : ... 903 (DRI) .............. i : .. . ..... . ..... : ... . . : jPerro-alloys!···i i .... !Perro-alloys! : ... . . . ..... . : : . . . ...... . . . : 1.027 (liquid steel) 1.027 (liquid steel) 1001 scrap 751 DRI . 251 scrap 1.000 (cc p roduct) 425 bille ts . 575 blaa.s 414 (vi re rod) 568 (sections) FIGURE 2 Outl ine configurat ions of the electric arc furnace re ference plants.

8 , .... S, ODD �.OJ.......................... . . . . . . . . . . . . . . .. . .. .. . . . . . • . 20.41 Lo•••• u.u ;; t".l...l ..w..l'f' g:,a: ra u $ II 4, DOD �....-4� !!'HI.!'.J ... • • DareCI � �ucllan & 2. 807 i " (57. 4111) - u • s. i 3,000 l:l � r Wn· fi , .... Mkl119 u 2, 021 3,UI i 2, 000 :6-Al •••• ! aleel· ., .... Mklll9 Mkl119 I, 408 1,351 CZI. ISJ I, 000 .. - ••••••• llt-.1\J. .C.h•• •.••..•• &nuoua '12 (4. n caat&ng 1211. 7st I cuan .a I Uo (16.3 I � 0 - --- --- - L-------��� �����-------L------L......_J . ... 0 lc:rep elld ......., ... DAI fed ere Nlerence fumeca plelll Nf-nce plena FIGURE 3 Ene rgy consump t ion in the re ference plants. TABLE 1 Energy Los ses for Integrated Re ferenc e Plant Ene rgy Los s n Source Mcal/tcs A MBtu/tcs Coke oven and by-produc t plant 515 2 . 04 S inter p l ant 433 1.72 BOF and cont inuous cas t ing operat ions 703 2.79 Hot roll ing 558 2.21 Cold roll ing 287 1 . 14 Bo iler plant 26 0.10 O ther operations _!i 0.18 Total 2567 10.19 !!.Mcal/tcs 6 10 calor i e s per ton of cas t or raw s te e l h 6 Mbtu/tcs 10 Br i t i sh the rmal uni t s p e r ton of cas t o r raw s te e l

9 The pos s ib i l i ty that col laborati on be tween fede ral laborator i e s , univer s i t ie s , and indus try could as s i s t in s o lving the long - range prob l ems of the dome s t i c s te e l indus try has been sugge s ted by members of the Pre s i dent ial Comm i t tee on Indus trial Compe t i t ivene s s , George A. Keywo rth, S c ience Advisor to the Pres ident , and Howard M. Love , Cha irman of the Nat i onal Intergroup. Dur ing the period from May to S ep tember 1984 , four task group s under the direc t ion of a jo int s teer ing comm i ttee made an intens ive and we l l-documented search for new approaches in s te e lmak ing , cas t ing , produc t development , and c ontrol engineering. As a result o f the s e s tudie s , opportun i t i e s f o r long-range and nove l techno logical deve lopment were ident i fied in two areas: the dire c t produc t i on o f l iquid s te e l from iron ore and the cas t ing o f near-ne t-shape s olids from mol ten me tal. OIP has incorporated the s e sugge s t i ons into i t s current program. AS SES SMENT OF TECHNOLOGI CAL OPPORTUNITIES The comm i t tee under took a review of the trends and prac t i c e s wi thin the indus try that re late to energy use to de termine what , if any , e fforts could be undertaken by DOE ' s Office of Indus tr ial Programs to ass i s t s tee lmakers i n reduc ing energy consump t ion o r i n us ing i t more e ffec t ively. Bas ed on i t s s tudie s , the c omm i ttee focus ed i ts attent ion on yield improvements , was te ut i l ization , and s crap recyc l ing. A mee ting was convened in Wash ington to rece ive and d i s cuss input from persons knowledgeable in the current was te and energy i s sue s fac ing the s teel indus try and on the s tatus o f techno logy relevant to these problems. Representat ives from the Office of Indus trial Programs par t i c ipated in the mee t ing , along with J . Ell iott ( Mas s achus etts Ins t i tute of Techno logy) , V . Fo l tz ( ARMCO) , R. Landre th ( Inland S teel Co.) , and T. W e i dner ( Be thlehem S teel Corp.) as invited speakers . The efficient use o f energy in ironmaking and s tee lmaking has been under s tudy by the indus try for a number o f years. This report ident ifies where DOE can play a role in ach iev ing implementation of new te chno logies for effe c t ive energy use in the iron and s te e l indus try and where DOE can as s i s t in the deve lopment of the s e te chnologies through generic re search and development that augments and comp lements the efforts of the indus try and others. Bas e d on the background information previous ly de s c r ibed and s everal o ther publ i shed report s (4,5), the c omm i ttee chose to direc t i t s at tent ion to four areas that appear to have promise for energy reduc t ion in s tee lmaking: • Energy and heat cascading and/or recovery • Decreased generation of me tal l i c was tes by proc e s s yi e ld improvement s • Incre as ed recycling of sc rap by improving scrap qual i ty and/or deve lop ing new proc e s s e s that can economically and thermal ly u t i l ize a higher rat io of scrap than the pres ent BOF • Improved treatment of sludges and dus t s to make them more amenable to recycl ing

10 TABLE 2 Projec t s Spons ored by the Office of Indus tri al Programs Re lat ing to Energy Use in the I ron and S te e l Indus try Program Objec t ive Formcoke Develop environmentally acceptab l e c oke manufac tur ing proc e s s Coke p e l l e t proc e s s Deve lop environmental ly acceptab le c oke manufac tur ing proc e s s Blas t gas i f ication Produce low- t o medium-Btu gas us ing i dle bla s t furnace capac i ty Coke dry quench Modify coke oven batte r i e s to permi t recovery o f h e a t re s ident in coke Direc t sme l t ing Deve lop proc e s s for direct produc t ion of s te e l of iron wi thout a b las t furnace Cupola furnace Permit off-gas recovery and combus t ion in modification cupola operation Ho t inspec t i on Deve lop proc e s s for inspec t ion and c orrec t ion and s carfing o f flaws in hot s teel slab s to perm i t cont inuous proc e s s ing to flat rolled produc t Computer control Deve lop hierarchical computer control sys tem for energy management in integrated s te e l mills I ron par t i cle Develop mathematical mode l for e lectric furnace me l t ing operat ions op t imiz ing energy requirements for me l t ing direc t-reduced iron ore and s te e l s crap Electric arc Develop computer model using new control furnace mode l ing me thods S l o t forge furnace Develop and demons trate modificat ions to improve furnace e fficiency Fluidized bed heat Demons trate commerc ial-scale furnace of fluidized treatment bed heat treatment o f me tal parts Nitrogen-bas ed Develop and demons trate nitrogen-based carbur ization atmo sphere for carbur izat ion o f s t e e l parts High-temperature Deve lop s ens ors to ob tain real-t ime proc e s s s ens ors for on; l ine analysis and control Thin s tr ip cas t ing Deve lop twin moving mold and planar flow whe e l cas ting technique s for th in s tr ip s te e l Source: An As s e s sment of the Indus trial Energy Cons ervat ion Program (3)

11 A discus s ion o f each o f thes e areas follows , w i th recommended ac t i ons or projec t s that c ould be undertaken by the Office o f Indus tr ial Programs to enhance the techno logy base ava i lable to the s te e l indus try for more e ffec t ive energy use. WASTE ENERGY RECOVERY Po tent ial improvements for energy recovery from was te s treams can be divided somewhat arb i trar i ly into four categories: 1. Te chnically proven concep ts that canno t be adop ted in a spe c i fi c plant becaus e o f plant-spe c i fic problems such as produc t mix, space avai l ab il i ty , logi s t i c s , e tc. 2. Technically proven concepts that are no t be ing adop ted but that prob ab ly would be i f demons trated in a wide vari e ty o f real i s t i c , real-p lant s i tuations 3. Technically proven concep ts that are be ing adop ted by the indus try as financ ing permits 4. Technical ly unproven concepts C learly , the Office o f Indus trial Programs has no role to play in category 1 and 3 concepts . Energy cons ervation via category 2 i tems would be enhanced by DOE funding o f demons trat ion projects , but thi s appears to be outs ide the s cope of the high-r i sk , high-payoff ph i losophy o f the depar tment . (A comp l e te l i s t ing o f new but technically proven concep ts that could be demons trated i s avai l able in the I I S I report.) Category 4 � tems c learly fal l within the scope of OI P ' s current charter . The c omm i ttee was advised during i ts de l iberations that making use o f the energy from was te gas s treams had an impor tant c onse rvat ion po tential but that it needed further technological development and ver ification. Thi s i s cons i s tent wi th the I I S I report (2). The I I S I iden t i f ie d the fol l owing was te-gas energy-s aving potent ials that require further deve lopment: • For the integrated p lant ( e s t imated s avings are shown. in parenthe s e s) --Coke oven gas s ens ib le heat recovery ( 19 Mcal/tcs) --Blas t furnace and BOF slag s ens ib le heat recovery ( 30 Mc al/tcs each) --Axial top pres sure turb ine operat ion with hot , dry cleaned gas (20 Mc aljtcs) • For the s crap and direc tly reduced iron-fed electric arc furnace plant --S team-cooled walled pane ls

12 The I I S I repor t further concludes that , in general , when choo s ing b e tween a var i e ty of energy-s aving op t ions , it is advantageous to concentrate on was te energy s ource s that are large ; as s oc iated wi th a gaseous phas e ; sui tab l e for recyc l ing rather than recovery ; and , in case o f s ens ib le h e a t recovery , at a h i gh temperature. In J anuary 1982 , the Gas Re search Ins t i tute (GRI) pub l i shed a report that inc luded an as s e s sment o f how energy could be us ed more e ffec t ive ly in ironmaking and s teelmaking (5). W i th regard to energy recovery and reus e , the report rec ommends the following as areas needing r e s earch: • Development o f low-cos t me ta l l i c materials wi th high-temperature s trength , creep res i s tance, and res i s tance to high-temperature corros ion • Deve l opment of h igh-ve loc i ty burners that can accep t high a ir preheat temperature s and provide high turndown capab i l i ty , and demons trat ion of such h i gh-veloc i ty burne rs on reheat furnac e s , soaking p i ts , and anneal ing furnaces • Demons trat ion of p late- and fin-type or o ther c ompac t , h i gh­ effe c t ivene s s recuperators on anneal ing furnac e s • Inve s t i gations o f ceramic mater ials t o charac terize mechanical and thermal properties and development o f improved fabricat ion and repair technique s Add i t ional areas recommended in the GRI report for research and demons trat ion on was te heat recovery include • Deve lopment of l ow-cos t , more compac t was te heat bo i lers • Improvements in flame control capab i l i t i e s when us ing higher temperature preheated air to ensure satis fac tory furnace operation • Me thods to reduce amb ient air inf i l tration into furnace s to minimize dilut ion of was te gas s treams • Use of elec tr i c arc furnace exhaus t gas e s to preheat s crap (6) and als o the use of BOF off-gases for s crap preheat ing • Use of Freon or o ther bottoming cyc l e s to recover heat l o s t from areas such as furnace wal l s and BOF hoods Re search s tarted at GRI in 1986 on a gas-fired sc rap me l ter w i th an integrated heat recove ry sys tem and on a gas-fired hot me tal trans fer sys tem with heat re covery . WASTE HEAT ENERGY An attrac t ive use of was te energy that has been deve loped but may ne ed a demons tration in the Uni ted S tates to ful ly document i t s advantage s i s scrap preheat ing w i th the o ff-gas from an electric arc furnace . A typ ical heat balanc e for an EAF indicates that up to 20 percent o f the energy (100 kWh/ton) leaves the furnace as hot gas e s; thi s is enough energy to

13 po tent ially preheat the s crap to 6so•c (1150°F ) . S crap preheat ing in Europe , fo r examp l e , is accomp l i shed in the charging bucke t w i th a spec ial hood . Reduc tions in energy consumpt ion (50 kWh/ton ) , e lec trode consumpt i on (2 to 3 lb/ton ) , and me l t ing t ime (6 to 8 minute s ) have been obs erved . In addi t ion , the zinc content of e lectric furnace dus t , a hazardous was te , i s increas ed , which makes i t a marke table produc t . WASTE REDUCTION THROUGH PROCE S S YIELD IMPROVEMENT F igure 3 shows that the energy consump t ion for a modern , energy­ effic i ent integrated s te e l plant would be 19 . 24 GJ per me tric ton o f cas t (raw ) s te e l ; for a modern, energy-e ffic ient electric arc furnace scrap­ based s teel plant it would be 8 . 49 GJ per metric ton of raw s tee l . Energy s tat i s t i c s spec ifically for integrated produc t ion or electric furnace produc t ion are not available . However, from a reported average o f 29 . 0 G J p e r me tric ton (25 MBtu/short ton) o f shipped produc t in 1985 , fac tored by the percentage o f integrated and EAF produc t ion, one can e s t imate the average energy consumpt ion for dome s t i c integrated EAF produc t i on in 1985 as 28 . 1 and 13 . 6 GJ per me tric ton , respect ive ly . Thes e diffe rences repre s ent the relative degree o f modernizat ion and energy effic i ency o f the average dome s t i c s te e l p l ant compared to the hypo the tical s tate-of- the-art plants dep i c ted in the 1982 I I S I s tudy (2). Integrated produc tion accounted for s l ightly more than 80 percent o f the energy consumed b y the dome s tic s te e l indus try in 1985 . Yie ld Performance Yield performance is the decimal ratio of fini shed tons to raw s teel tons expres s ed as a percentage . Table 3 shows that, in the pas t 10 years, average dome s t i c s teel produc t i on yie lds have increased from 70 percent to 83 percent . Thi s increase is highly corre lated (r - . 996 ) w i th the increase in percentage of s teel cont inuously cas t . For every percent increase in raw s te e l cont inuous ly cas t, produc t yield has increased almo s t one-half percent . Thi s i s s omewhat mi s leading . Probably l e s s than half o f the improvement i n y i e ld can be attr ibuted directly to continuous cas t ing . The res t i s a reflec t ion of coro l l ary improvements in downs tream proce s s e s and the clo s ing o f o lder fac i l i ties . In 1985, the indus try continuously cas t 44 percent o f the raw s teel produc t i on and exhibited a raw-s teel- to-produc t yield of 83 percent . Po ten t ial Ene rgy S av inss Base line figure s of 25 GJ per me tric ton of raw s te e l for integrated produc tion and 13 GJ per me tric ton for EAF produc t ion are us ed here to analyze the e ffec t o f incremental yield improvements on ene rgy cons ervation for the indus try . Thi s provides a cons ervative e s t imate o f po tent ial s avings .

14 TABLE 3 Indus try Y i e lds and Cont inuous Cas t ing Rat i o s Year Percent Cont inuous Cas t ing 1975 69 9.1 1976 70 10 . 5 1977 73 12 . 5 1978 71 15 . 2 1979 74 16 . 9 1980 75 20 . 3 1981 73 20 . 3 1982 82 29 . 0 1983 80 32 . 1 1984 80 39 . 6 1985 83 44 . 4 Ayield calculat ions do no t take into acc ount annual inventory variations . By 1995, total dome s t i c shipments (demand - imports + exports ) i s projec ted to be no more than 63 mi l l ion me tric tons . A t current yie lds thi s equates to a raw s te e l requirement of 76 mi l lion me tric tons . S ix ty pe rcent o f the s e shipments i s expec ted to be produced by integrated plants, p r inc ipally in the form o f plate and l i ght flat-ro lled products . The remaining 40 percent w i ll be produced in electric arc furnaces . Th i s produc t i on rat io and the basel ine figures given proje c t a n annual energy consump t ion by the dome s t i c s teel indus try of 1, 760 , 000 GJ or 1 . 67 quads i f the raw- s t e e l- to-produc t yields were to remain the s ame . I f yie lds were imp roved to 100 percent, annual ene rgy requirements would be reduced by about 0.2 quad . This leve l o f improvement, whi l e unreal i s t ic, prov ide s an absolute l imi t o n achievable s av ings through yield improvements alone . S ources of Yield Improvements There are three po tential areas for fur ther yield improvements in the indus try . The firs t is to continue the ins tallation o f s tate-o f- the-art continuous cas ters fo r s labs and blooms . Minimills or spec ialty mil l s that can ut il ize bille t cas ters a r e now almo s t 100 percent cas t . A prac t i cal lim i t is for 90 pe rcent o f all s teel to be continuous ly cas t .

15 (Sect ion s ize and o rder s ize cons traints w i l l preclude certa in products from be ing cont inuous ly cas t . ) Increasing the cas ting ratio to 90 percent should increase overal l yie lds to 90 to 91 percent , w i th a consequent energy s avings of 0 . 1 quad . No new technology is needed to achieve thes e energy s avings . In fact , s ince 1985, addi t ional cas t ing fac i l i t i e s have either been installed or p l ans have been announce d to increase the level of cas ting capacity to 70 percent of the projected 1995 raw s t e e l requirements f o r integrated plants . A second potential area for yield improvements i s the mode rnization o f downs tream roll ing and proces sing faci l i t ie s and improvement i n pract ices related to the se fac i li tie s . There i s no single generic need in thi s area . Rather, the requirements t o achieve improved y i e lds are spec i fic to each fac i lity and operation . App l i cation o f current b e s t prac t ices could probably improve overa l l yields an additional 2 to 3 percent, b o th in integrated p l ants and in spec i a l ty p lants . S ome improvements w i l l occur as a higher percentage of capac i ty is taken over by new minimi l l s . The third potent ial area for y i e l d improvements, whi ch to s ome degree overlaps the preceding two, is near-ne t-shape cas t ing . Suc ce s s ful deve l opment o f thin s l ab cas t ing or s trip cas t ing could supp lant conventional slab cas t ing and could avo i d the need for moderniz ing cer tain downstream fac i l i t i e s . I t i s e s timated that thin slab cas ting could provide 2 to 3 percent added yield s avings over s l ab cas t ing for l i gh t flat-ro l le d products . On the basis o f the preceding analys i s , the po tent ial energy s avings from y i e ld improvements alone would be about 0 . 02 quad . To summ a r ize , energy s avings o f the order o f 0 . 10 to 0 . 15 quad are po tent ially ava i l able through the improved yield performance of domes tic s teel plants . The bulk o f thi s improvement is attainable through the app l icat ion of currently available cont inuous cas t ing and proce s s te chno logy . S CRAP RECYCLING (7,8) The U . S . s teel indus try consumed 1 . 7 quads of energy in 1985 , which represents ove r 6 percent o f the indus trial consump t ion . Producing s teel from scrap requires l e s s than 45 percent o f the energy needed to produce it from ore . The major me thod of us ing sc rap is an electric arc furnace, which accounted for about 34 perc ent of s te e l produc tion in 1985 . If elec tric furnac e s teel produc tion could b e increased t o 50 pe rcent o f the to tal produc tion, 0 . 20 to 0.22 quad of ene rgy could be conserved . Increasing s crap consump tion in the BOF or the deve l opment o f o ther scrap-bas ed s tee lmaking te chno logies would also cons e rve ene rgy. For a signifi cant increas e in elec tric s teelmaking to occur, there mus t be suffi c i ent sc rap o f reas onable quali ty ava ilable, and the produc t s then can be produced in an electric arc furnace expande d to include low-carbon and lower ni trogen s te e l s . There i s a tremendous surplus o f sc rap in the Uni ted S tate s . .I t is e s t imated that in 1985 over 120 mil lion tons o f ob sole te s crap (excluding home s crap and promp t scrap ) were generated and only 36 mi llion tons were

16 s old to the U . S . indus try . The s c rap indus try exported about 9 . 5 m i l l ion tons. It i s e s t imated that there are 744 m i l lion tons o f s crap available ; this figure could be disputed regarding what is ac tua l ly recoverab le, but there is no doub t that there are adequate quant i tie s of s crap avai l ab l e and that every year the Uni ted S tate s generates more sc rap than i t us e s . The next que s t i on concerns scrap qual i ty . Scrap in s teel p l ants i s of two general types: home s crap generated in the p l ants and purchased scrap . Home s crap currently repre sents about 40 percent o f the s te e l indus try s crap requirement, and i t is of good qual i ty . However, as more continuous cas ting i s put into produc t ion, the amoun t o f home s c rap w ill decreas e . Purchas ed s crap can vary in quality . The major e l ement o f concern i s copper; the copper content o f typ ical types o f purchased s crap is l i s ted in Tab l e 4. Currently many of the produc ts produc ed in electric furnace shop s are s imple shapes such as reinforc ing bar and angles, for which copper, nickel, and molybdenum are no t a major concern . Howeve r, if electric furnace s teel produc tion is to increas e s i gnificantly, i t will be neces s ary to produce more o f the c r i t ical grades . For examp le, drawing s teel for automo t ive and appliance use i s a major produc t . Acc ep tab l e l evels o f copper and other residual elements for draw ing s teel are l i s ted in Tab l e 5 . It can be seen that these levels are far be low the leve l s present i n mos t c ommerc ial s c rap . S ince the copper is o ften present a s a phys ical m ix ture or as composite layers, phys ical and hydrome tallurgical separations could p o s s ibly remove much of i t . TABLE 4 Copper Content of Commercial Scrap Sc rap Type Perc ent Copper Manufac turers' bundles 0.0 7 Number 1 heavy 0 . 18 Number 1 bundles 0.20 Shredded 0 . 23 S ource: Inland S teel 1983 TABLE 5 Max imum Levels of Re sidual Elements for Drawing S teels Maximum Percent Type Cu Ni Cr Mo Sn Total Deep drawing s teel 0.06 0.1 0.07 0.02 0.0 1 0.12 Drawing quality, commercial qual i ty t in (�) 0.1 0.1 0.0 7 0.03 0 . 015 0.16 T in (cr i tical appl ication) 0 . 06 0.04 0.04 0 . 02 0.02 0.16

17 I t i s c lear that the s teel indus try can conserve energy b y produc ing more s teel from s c rap . In addi tion , s crap repres ents a comp e t i t ive advantage for U . S . s teel producers over mos t o ther countries . However , whereas the availabil i ty o f scrap i s great , the amount o f quality scrap ava i lab l e may no t al low producers to sub s tantially expand the us e o f s crap in s teelmaking . This prob lem was recognized as a major one by the S te e l Indus try/Federal Laboratory Task A Adviso ry Comm i ttee ("Keyworth S te e l Ini tiat ive" ) . Th a t comm i ttee recommended a major four-po int program for scrap at a funding leve l o f about $400, 000 to $500, 000 per year . The program dealing with s crap re finement cons i s ted o f • Physical separation----A projec t t o improve physical s eparation initially looking at the e ffec t of magne tic flux and improved sight ing methods, to be done by Inland S teel Company wi th input from the Ins titute of S crap I ron and S teel • Hydrome tal lurgical separat ion----W ork on leaching o f s c rap with various reagents , to be done at Idaho Nat ional Laboratory • Pyrome tal lurgical s eparation---- Examination o f the thermodynami c s, kine t i c s , and feas ib i l i ty of sulfide treatments for removing c opper , to be done by Carnegie-Me llon Univers i ty ; consideration o f o ther nove l me thods , such as formation o f comp lex hal i de vapor spec ies and novel fluxes, to be done by Argonne National Laboratory • Res i dual elements---- E xaminat ion of the ent ire que s t ion o f res idual elements, such as max imum coppe r leve l s, what o ther elements are of conc ern, res idual l evels of elements in various scrap forms, what can be achieved by scrap b lending, and the economics of improved physical s eparat ion and o ther new treatments, to be done by an appo inted task force As of December 1986 this program has no t been implemented. The greater us e o f s crap in s teelmaking i s po tent ially a s ignificant method of reducing energy consumption by indus try . There is adequate s crap available, but the quality of the s crap may no t al low for s i gnificant growth of elec tric-furnace s tee lmaking to new produc t areas . There are at present no major research e fforts in the area o f improving s crap quali ty . For scrap-bas ed e lectric furnace s teelmaking to increase its share o f s teel produc tion signi ficantly, i t will also b e nece s s ary t o expand the range o f produc ts that can be produced. Currently, very l i ttle cold-rolled she e t is produced in EAFs becaus e the steels produced there normally have nitrogen leve l s higher than is accep table for thi s produc t. S tee l s produc ed in a BOF general ly have lowe r nitrogen contents. An alternat ive to EAF s tee lmaking us ing s c rap is the us e o f large-furnace induc t ion melting of the s crap p lus coke plus silicon to provide the charge fo r the BOF . Cold-rol led she e t used in the automo tive and app l iance indus tries , fo r examp le, represents a large percentage of to tal s teel produc tion . Therefore, proces ses mus t be developed for produc ing s teels w i th low

18 ni trogen contents in the EAF . L ikewise, there is an increas ing demand for low-carbon s teels (le s s than 0 . 03 percent ) . At pres ent thes e s teels have to be produce d in a BOF . Proc e s s e s should be developed for the produc t ion of low-carbon s teels in an EAF to us e more recyc led s crap . IMPROVED POLLUTION-ABATEMENT TECHNIQUES The U . S. i ron and s teel indus try use s a var i e ty of was te treatment technique s common to many indus trial manufac turing operati ons . Included are was tewater treatment by flocculation and precip i tation for removal o f contaminants prior to dis charge to munic ipal treatment sys tems o r t o surface waters, land-fill ing o f s o l id was tes, particularly fly ash materials and oily m i ll scales, removal of par t i culate matter from off-gas s treams via s crubbers and/or electrostatic prec ipitators, and deep-well injec t ion of proc e s s was tewaters w i th high chlor ide content, which canno t be eas i ly treated or e ffec t ively recyc led to the s tee lmaking proces s . In general, thes e was te-abatement proce s s e s used by the iron and s te e l indus try a r e mature, proven technologies that have been in u s e f o r many years . Overall , the energy consump tion for p o l lution abatement in the i ron and s te e l indus try cons t i tutes only a small frac tion of the total energy us ed in thi s indus try . In general, l e s s than 2 percent o f total energy consump t ion is u t i l ized in p o l luti on-abatement ac tivities, w i th by far the large s t part of this be ing for movement of relatively high-temperature o ff-gas es from the var ious s te e lmaking proces ses . Efforts toward improved po llut ion abatement in this indus try have been dr iven by the opportunity for recycling and reus e of was te materials containing valuable raw material components rather than by the economics o f energy cons e rvation per s e. Gas Handl in& The high pres sure drop required for e fficient operation of b o th cyc lone s eparators and wet scrubbers re sults in a large energy use for gas handling, and the level of energy required is further exacerbated by the need to cool the gases, which can reach temperatures o f 3000°F, prior to treatment for removal and recove ry of the particulate matter . At pres ent, volume tric cool ing with ambient air is frequently prac t iced at di lution ratios as high as 100 to 1, thereby greatly inc reasing the size o f the equipment requi red as well as the hors epower requi red to move the o ff-gases through the par t iculate-removal equipment . Ano ther significant issue in the reus e o f off-gases and reclamation o f was te heat in tho s e gas e s is the submic rome ter-size par t i culate matter they contain . Th i s par t iculate matter is typically be tween 1 and 2 percent up to 44 �m. with an average of 2 to 10 �m. Impuri t i e s in th i s particulate matter frequently re s tr i c t the potential use of the hot gases, and the refore the challenge is the removal of the submicro­ meter-s ize par t i culate matter wi thout l o s s of the s ens ible heat content of the gas.

19 Indirectly related to g a s handling i s the fac t that e lectric arc furnace dus t has been l i s ted by the Environmental Pro tec t i on Agency as a hazardous was te under the regulations o f the Res ource Conservat i on and Recovery Ac t . Thi s extreme ly f ine dus t , ranging in s ize from 0 . 1 to 10 pm, i s formed in the elec tric furnace by me tal vaporizat ion , sub s equent reaction w i th oxygen w i thin the furnace , and depos i t i on on condensed nuc l e i . I t is cons idered a hazardous was te because o f the pres ence o f leachab l e me tals such 8$ lead , cadmium , and chromium . S ince dispo s al i s a prob lem , energy-effi c i ent proces sing techniques nee d to be inve s t igated to upgrade these par t i culate was tes to useful p roduc t s . As no ted earl ier , i t has been reported that s crap preheat ing us ing the off-gas e s from an EAF reduces the amount of dus t and increas e s the zinc content, which p o s s ib ly makes the dus t marke table . Was tewater Handl ing A typical s teel mi l l consumes between 3 5 , 000 and 80 , 000 gal l ons o f water per t o n o f fini shed produc t, pr imar i ly f o r cooling us es . Configurat i on o f the m i l l and the type o f proc e s s emp loyed can have a s i gnifi cant e ffec t on the vo lume of water used and the volume o f water d i s charged through the was te-treatment proce s s . Hors epower requirements for was tewater treatment per se are general ly no t exc e s s ive , al though s ignificant quant i t i e s of compre s s ed air are needed for extended aerat i on o f o ily mill was tes from p i ckl ing operations and hot-rolled was te . Deep - Well Inj ection S trong p i ckl ing was tes may contain up to 10 percent hydrochloric acid , for whi ch the only effe c t ive disposal technique i s deep-we l l inje c t ion . Energy requirements for this operation depend heav ily on subsurface geo logical configurat ions and the resul tant pres sure required to force the was te mater i a l into the sub surface s trata, but the s e are not s ign i f icant in terms of overal l energy us e . S ludge Handl ing Sludges from clas s i fic ation and o ther co llection proces s e s in s ome cas e s are difficul t or cos tly to recyc le because of their mo is ture content . The s e materials frequently contain mois ture in the 30 to 40 percent range, and the abil i ty to fur ther dewater the s e material s would reduce the heat requi rements when they are recyc led. The po tential energy reduct i on in this area is s igni ficant; even though dewater ing proc e s s e s have been extens ively s tudied, a further review o f dewater ing techniques i s probab ly warranted . O i ly Mi l l Was t e s A review o f al ternate technique s invo lving s o lvent or de tergent c leaning of o i ly mi l l was tes to perm i t recyc l ing rather than disposal in a landfi ll s e ems appropriate because i t may o ffer a combined benefit o f add i t i onal was te reduc tion along wi th reduced energy consump tion .

20 Summary o f Po l lution-Abatement Tecbnigue s The mo s t s ignificant potential for improvement in the area o f p o l lution abatement appears to be i n the area o f recovery o f contaminated dus t from high-temperature gas s treams at proces s temperature, whi ch would perm i t the s e gas e s to be reus ed as fuel o r to preheat s c rap mate r i a l s b e ing recycled . W i th the energy consump tion f o r p o l lut ion abatement represent ing only be tween 1 and 2 percent of total energy for s te e l manufac turing, the potent ial returns d o not appear to be suffic ient t o jus t i fy s i gnificant e ffort i n this area . The ul timate usefulnes s and attrac t ivene s s of energy-reduc tion technique s wil l be offs e t by added cap i tal requirements for the ir implementat ion, and this w i l l comp e te w i th cap i tal requirements for proc e s s modification . RECOMMENDATIONS FOR THE OFFICE OF INDUSTRIAL PROGRAMS Even though revo luti onary advances in s tee lmaking p roc e s s e s, was te reduc t ion, and s c rap reus e are no t ant icipated, many sugge s t i ons have been made by various groups for techno logical advance s that, i f adopted, could improve energy us e by the i ron and s te e l indus try . As a result of i t s revi ew o f pub lished informat ion and dis cus sion w i th individuals knowledgeab l e about the s tatus o f techno logy app l icab l e to the indus try, the comm i ttee recommends that the fo llowing areas be considered for inc lus ion in res earch and deve lopment programs of the Office of Indus trial Programs : 1. Re search and development tasks ident i fied as a part o f the S tee l Ini t i a tive should be incorporated in OIP ' s program, even i f spec ial additional funding i s no t appropriated by Congress. In particular, program plans should be advanc ed by OIP for ( a ) refinement and reus e of s crap as de s c r ibed in the four-point program rec ommended by the Task A Advisory Committee, enc ompassing research on physical s eparation, hydrome tal lurgical s eparation, pyrome tal lurgic al s eparation, and e ffec ts o f res idual contaminants in s crap and (b ) deve lopment and improvement of near-ne t-shape forming technique s such as e l e c tromagne tic cas ting, spray cas t ing, and tw in ro l l cas ting . 2. In addi tion to the recommendations related to the recyc ling o f s crap, i t i s particularly important that proce s s e s should be deve loped t o produce s te e l s low i n nitrogen and carbon in an EAF t o expand the us e o f s c rap. 3. Imp roved ins trumentation and contro l procedure s in downs tream areas, aimed at identifying and eliminat ing de fec ts in cold-ro l led and ho t-rolled s l ab s and she e ts, should be deve loped and demons trated . 4. Devel opment o f cos t-e ffec tive technologie s for the recovery o f energy in was te s treams should b e pursued . App licat i ons with in the s teel industry should be inc lude d as a part o f OI P ' s was te heat recovery projec ts. Par ticular at tention should be dire c ted to the removal o f contaminated dus ts at proces s tempe ratures s o that the gas e s can be reused wi thout reheating as well as to the use of EAF o f f - gas directly for p rehe at ing s crap.

21 5. Research should also b e directed toward lower c o s t ceramic mate rials for use in recuperators as well as toward me tall ic material s . The development o f low-co s t recuperators that can operate re l i ably unde r the thermal , chemical , and ero sive cond i t i ons character i s t i c o f iron and s teel operat i ons is an attrac t ive objec t ive . Th i s w i l l require the ident i ficat ion and deve lopment of both low-co s t , high-temperature materials (me tall i c and/or ceramic ) and methods to fabricate them into suitab l e recuperator des igns . In particular, the comm i ttee sugge s t s that OIP pursue thi s objec tive p r imar i ly by support ing ac tivity to exp lore the potent ial for thi s use of the materials or proce s s e s emerging from exi s t ing extens ive high-tempe rature materials deve l opment programs such as thos e o f DOD o r o ther e l ements o f DOE . Cooperat ive ac t ivi t i e s to modify the produc ts o f such programs might then fo l l ow. REFERENCES 1. Data prov i ded by the American I ron and S tee l Ins t i tute . 2. Energy and the S te e l Indus try . International I ron and S te e l Ins titute , Comm i t te e on Te chno logy, Brus sels, 1 9 8 2 . 3. An As s e s sment o f the Indus trial Energy Cons ervat ion Program , Volume 2: Final Report . Nat ional Materials Adv i s ory Board , Publicat ion NMAB 3 9 5 - 2 . Washington, D . C . : Nat ional Academy Pre s s, 1 9 8 2 . 4. Analys e s o f Po tent ial Ene rgy Cons erving Proce s s e s in High Temperature . Prepared for Office o f Indus trial Programs, U . S . DOE, by Arthur D . L i ttle, Inc . , Sep tember 1980 . 5. Indus trial Energy Use, F inal Report, Vo lumes 1 and 2 . Gas Re s earch Ins titute Report No . GRI-79/0103 . 1, Chicago, 1982. 6. J ohn A . Val l omy . The Cons teel Proce s s in Nor th Amer i c a . Paper presented to the AIME 43rd Furnace Conference, Atlanta, December 1985. 7. R . J . Fruehan . S crap in I ron and S tee lmaking . I ron and S tee lmaker, May 1985 . 8. R . J . Fruehan . Sc rap in I ron and S tee lmaking : Te chno logies to Improve the Use o f S crap . I ron and S teelmaker, July 1985 .

Chap ter 3 IHE P ETRQCHEHI CAL INPUSTRY The pe trochemical indus try i s one o f the nation ' s large s t energy consumers ; in 1 9 84 a total of 6 . 1 quads of energy, including 2 quads as feeds tocks, was consumed by thos e companies included in S tandard Indus trial Clas s i f ication 28 ( 1 ) . Companies wi thin the indus try inve s t heavily in techno logy, and the success o f the indus t ry i s buil t on co s t-effective proprie tary proces ses to produce an ever-expanding array o f produc ts f o r the commerc i al and indus trial marke tplace . S ince the pe trochemical indus try p o s s e s s e s a s trong technology base, i t has addres sed energy conservation mainly on its own ; only a few proj e c t s relating t o this industry have been undertaken by the O f f i c e o f Indus trial Programs . The re sults o f a previous review of OI P ' s projects for the chemical indus try are s umma r ized in an ear l ier report (2). As a part of i t s review o f effic ient energy u s e through was te reduc t i on and recyc l ing, the comm i ttee undertook a b rief review o f current prac t ices within the pe trochemical indus try to de termine if there were unfi lled technol o gy needs that should be addre s s ed b y OIP. A mee t ing was convened in Washington for the commi ttee to gather information from persons knowledgeable in ene rgy us e, was te recycling, and was te treatment techno logies of the indus try . E . Kranz ( S tone and Web s te r Engineering Corp . ) , D. Mai s el (American Ins t i tute of Chemical Engineers ) , A . Manches ter (He rcules Inc . ) , V. S tewbart ( Dow Chemical ) , and M . Throdahl ( formerly Mons anto Company ) par t i c ipated as inv i ted speakers . From the information pres ented, the comm i t tee concluded that 1. The mos t cri tical problem currently facing the pe trochemical indus try i s the treatment and disposal o f hazardous was tes . Inc ineration i s the techno logy o f cho ice used by the indus try to s o lve these prob lems . One reviewer o f thi s report has provided the fo llowing info rmation , which the commi ttee endorses . Mo s t pe trochemical p l ants are as s o c i ated wi th p e troleum refiner ies, and it is o ften p o s s ible to dispo s e o f 23

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