CEE Oct-Dec 2002

subsequently expanded to 2,250 tpd by adding a dry-process kiln. In July 200 1, Fuller India Limited (F IL) was awarded a contract for upgradingofthe KIID– supplied ILC pyro system from 2.350 to 3.000 tpd clinker, and a subseque nt order for cooler modification was placed in August 2001. The modification was planned to take place in two stages, the first one involving connecting up of the new prehcater and th e second being the cooler modilication with CFG grate plates. FIL's scope of suppl y included a new 4- s tagc ILC preheater, prehcater fan, kiln feed system and cooler up grading, the latter including installation ofCFG grates in the ex isting origi nal KIID cooler with IKN lixed inlet section. The main feature s of the upgrading project arc: Connecting up th e new preheater tower in a record time of 19 days. Increasing production capacity from 2.350 tpd and stabilising it at 3,200 tpd clinker. Reducing specific fuel consumption li·om 780 to 740 kcal/kg clinker. Cooler loss (coole r vent + clinker) at I05 kcal/kg clinker. Clinker exit temperature less than I I0° C (Ref. 0° C) Specific power consumption of the preheater fan at 6.7 kWh/tonne of clinkct Specific power cvns um pti on of the cooler fans at 4.0 kWh/ tonne of c linker. The hus iness rel atio nshi p bet\\ een Dalmia Cement and Fuller Indi a has developed int o a deep bond of mutual re spect and appreciation. Courte.1y : Hig,h/ighls – Nm·emher 2002 !'6, Fax: t-/536301820 1:.'-ma i I. inf'orqjlsmidt h. com URL: \1'\I'H'. flsmidth.com IMPROVING ELBOW DESIGNS Randy Dillard ond Ken Nichols. A. J. IVe/!er Corp., USA North Texas Cement had been experiencing extreme wear in the back-18° of its mitered elbows transporting raw material into the ball mill grinding chambers. Due to the hi gh maintenance cost and production interruptions that repair was expected to cost, the company asked the A.J. Wel ler Corp. to find a cost eflective solution. Replacement orelbow may take anywhere from 4-6 hr and requires the mill to be shut down. Any leak in the elbow will allow water to leak and create housekeeping and safety iss ues and, although tem porary repairs or patching allow the mill to con tinue to run. they requ ire consta nt maintenance and last for only a shott period. At this facility, replacing the raw-feed inlet elbow requires a shutd0\\'11, causi ng a loss of I000- 1500 t of material due to production interruption. One elbow design used chrome carbide overlay plate. This material is 600 BHN with 1/4 - 3/8 in. overlay. but it is not designed to withstand extreme impact. Another more common design elbow utilises Hi-alumina ceramics til es to line th e back- 180°. Hi-alumina ceramics are one of the harde s t known inorganic substances and can handle limestone abrasion. However, it will not hand le extreme impact. and breakage often occurs, allowing the aggregate to attack the elbow\\ ails. High-chrome cast elbows are also used in this application. With a hardness ranging from 500-600 Bl iN, they perform well against extreme abrasion although, again, thi s material is not designed to withsta nd high impact. Hi gh– chrome cast elbows are very brittl e and subject to crack ing in impact 34 applications. In add ition, high– chrome material can not be patched or welded, cl im inating the possibility of any external repai rs clue to cracks. Complete technology solutions - ! laving in spec ted the wear patterns in side the elbows, the Weller engineering team observed that there was no breakage to the ceramic tiles located on the high area of the walls. Since ceramics are cost effective in hi gh \Near areas, Weller chose to use the ceramic ti les in the specillc areas where wear was high and impact minimal. The tile breakage only occu rred in the lower 90" of the elbows and the Weller so luti on was to usc Weller WBL-700 wear blocks to line this lower-90'' arr~. The Weller Wl3L- 700 wear blocks are engineered to si mult aneously withstand high impact and abrasion. /\n ultra hard grade or ch rome nickel alloy (700 BIIN) is cast unde r tight control of selected chemistry and heat treated for fine micros tructure. The component is then meta llurgically bonded to a mild stee l backing plate. Tbe backing plate absorbs the im pact preventing the hard cast mate rial from crackin g . as this composite material is more impact resistant than any other material that is currentl y available. The l- in. thi ck Wel ler WL-3L- 700 wear blocks \VCrc 111 itercd on the sides and end s in Lhe same manner as pipe bric k. They were litted imo the lov,er 90'' of the elbow along with the l-in. thick ceramic tiles to produce the same internal– flu sh fit. Ano th er design consideration was to fl ange the lower 180'' of the elbows making replacement o r repairs po ss ible without removing the elbo\\ s. Courtesy: IVor!d Cemenl. .·III,R 02. Pp-3- --1 fmail: mai/la worldcemeni.C0/11 II ·uh: 11'11'\l'. wor/ dccmenl.com J