( STORAGE TECHNOLOGY ) I C...

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Domes are imp lemen ted in many diverse appl icat ions and dome and s i l o

storage i s an i m p o r t a n t consideration for any cement plant in terms of housing clinker, cement, o the r raw matenals, and vanous so l id fuels.

I C R has created t h i s compi la t ion which deta i ls recent technology, insta l la- t i o n s and t h e general expenence of some of the cement industry's leading

storage companies as w e l l as re la ted technology such as stacker and reclaimer systems. The companies h igh l i gh ted i nc lude Geometnca Inc, Clyde Matenals Handling, FLSmidth and Temor.

Geometrica Inc Coa1 storage - a clwn, safe ond cost- saving solution to power cement plants Grupo Cementos de Chihuahua SA de CV (GCC), one of the top cement producers in Mexico, decided to buiid two iongitudinal storage enciosures t o contain i ts coai stockpiies early this year. It is GCCs iatest and smartest aiternative t o power i ts cement piants with coai while facing the skyrocketing price of natural gas and other petroieum fuei products. I n line with i t s high degree of concern for the environ- rnent, GCC contracted

first shape with dimensions measuring 56m width x 95m iength x 25.47m height. The structure aiso includes a half dome with a radius of 28m.

Geometrico's odvantages The Geometrica system was selected instead of conventional weided and boited structures. I n the case of the Samalayuca structure, GCC wanted to maintain a uni- form overaii appearance with the two Geometnca structures aiready instalied i n 1994 and 1997. I n addition, GCCs satisfac-

Two 122m diomcter aluminium coal stomge domes for JEA of Florida from Geometfico inc

t ion with the performance of the current domes i s what encouraged it t o choose the Geometrica system again. A t the Chihuahua plant, ali of the existing storage buiidings are conventionai, yet GCt's decision for the Geometrica system was based on:

a very attractive cost-efficient price gaivanised steei providing higher dura-

bii i ty and low maintenance benefit a totaiiy prefabricated structure reducing

overall construction labour hours whiie easy instailation can be achieved by semi- skilled and unskiiied labour

prior satisfactory experience with Geometrica domes

appeaiing appearance enhances GCC's image and draws visitor's attention.

Coverpd or open cool stockpiles? A coupie of decades ago, poliution and environmentai issues were not a major issue. Naturaily, back then, coverage of open coa1 piles was often not necessary. I n addition, stockpiles differ in size and shape, open stockpiies worked weli t o

accommodate various Geometrica, Inc (Houston, Texas, USA) t o cover the two coai stockpiies t o contain coai dust and t o maintain burning efficiency i n a ciean and safe way. Geometrica aiso suppiied GCC, in 1994 and 1997, two buik storage enciosures for iimestone and other aggregates.

The new coai storage for the Samalayuca cement piant is a paraboiic barrei vault, 56m wide, lOOm iong, and 25.47m high. The length inciudes a haif dome with radius of 28m. The other coai storage, iocated at GCCs piant i n the city of Chihuahua, i s identical t o the

This cool stomge dome, is locoted ot Grupo Cementos de Chihuohuo in the city of Chihuühüü. The pümbolic bomí vüült has dimensions Of 56m m'dth x 95m íength x 25.47m height. it m.11 be completed by the end of November 2002.

iength and shape of piles,

coverage options. Containment was therefore sporadic and migration of coai particles to other piant areas was very com- mon. However, the new chailenge of the green- house effect and general environmentai con- sciousness has generated a growing demand t o address environmental issues. Nowadays, any poliution, even in remote areas with i i t t le or no direct effect on

l 1- i the pubiic, i s a poiiticai

coai stockpiies demanding

50 there was no need for

l il -& : - - and public concern. Open L B G .

INTERNATIONAL CEMENT REVIEW / DECEMBER 2001

STORAGE TECH NOLOGY

a cover has become a trend giobally. Geometrica's enclosure structures meet such a demand.

I n fact, covered stockpiles are protected from rain, wind and moisture buiid-up. Dry coai burns more efficiently and the pile is protected from erosion and run-off. As dry stockpiie reduces the risk of moisture build-up i n pockets, it can min- imise spontaneous combustion. Furthermore, dry coa1 does not need t o be processed from mois- ture removal, an expensive and potentially explosive procedure. Containment of fugitive coal dust also means additionai cost savings on plant ciean-up and equipment maintenance, as weli as reducing materials ioss.

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minimum for routine mainte- nance. The success of the Dome Valve i s due t o its unique design. Found in over 200,000 applications worldwide, including handling even difficult, abrasive materials in some of the most hostile process environments anywhere, it uses an inflatable seal arrangement t o ensure a pressure tight fit against the surface of the dome when in the closed position.

The seai automatically deflates before a single moving

ihese twu domes of difkmnt shapes far Cementos de Chihuahua m m part rotates a quarter turn to designed and built during 1994 ta 1997. ihe circulor limestone stamge is Open the vaive, preventing it 84m diameter. ihhc longitudinal has a span of 65m ond 124m length, for from coming into contact with the homagenising bed.

A sufe Geometricu coaf dome With regard to coa1 storage, explosive dust and corrosive materials present chailenges t o storage and protection of both the materials and the surrounding environ- ments. Concrete storage domes and silos have traditionally been favoured over steel or wood for their durabil ih and safety features, but lack the large spans required by iarger stockpiies. Coal stockpiies are notoriousiy iarge. However, Geometrica's innovative metal domes can easily break this iong-held tradition with the foliowing inteiligent features:

offering long span capabilities from 50-300m, ie, 150-1000ft. with no interme- diate supports

designing round galvanised steei tubes to reduce the surface where dust accumula- tion can settle on the supporting structure

utilising patented internal ciadding designed to prevent any dust accumulation on the structure altogether.

Geometricu - your dome sofution Space frame technology first took shape i n the mid-1960s for various architecturai appiications and i s st i l l in use today. Industrial use of space frames in the iast 10 years has deveioped into a cost-effec- tive alternative for industrial bulk storage.

. Geometrica is at the forefront of this industry, suppiying vanous shapes, sizes and types of iong span enclosures for coa1 and other raw materials.

As the industrial worid moves forward in this new century Geometrica wil l be faced with more responsibility for the

global environment. Higher profits require fiigher productivity and efficiency. Covered coal storage is already a requirement in many countries and others w i l l soon foilow. Geometrica's cover coa1 storage design offers cost-effkient burning and safer, cleaner plants. By implementing Geometrica domes for its coa1 storage, Grupo Cementos de Chihuahua has found an intelligent solution and pioneered their use in Mexico.

Clyde Materials Handling Clyde Materials Handling has been awarded not one but two orders for i ts Dome Valve from Eternit UK's Widnes piant i n Cheshire, after the world's most effective fast clos- ing, bulk materials cut-off vaive was given the thumbs up from the cement industry.

After a recommendation from Castie Cement in the UK, Eternit's Brian Riiey first approached Ciyde i n September 2000. The company, which manufactures and distrib- utes building materials. had been having repeated problems with a valve fitted on its iimestone silo. It was looking for improved valve Me, low maintenance and reliabiiity for maximum productivity.

A 150mm bulkhead Dome Valve was ordered and installed on the externa1 works iimestone silo. Two months later, after experiencing a dramatic improvement i n uptime resulting from use of the original valve, the company specified two addi- tional lOOmm and 150mm Dome Valves to replace unreiiable knife-gate vaives on its cement handling hopper outlet.

Since then, there have been no more problems with jamming or cement powder spillage and downtime has been cut t o a

any material and allowing a ful l bore, uninterrupted flow. Not

only does this avoid the risk of material build-up within the vaive body, it also reduces wear on the valve. As a result, ser- vice l ife has been shown i n appiications t o be extended by up to as much as 800 per cent when compared with other bulk and powder handling valves on the market.

For example, a t Westbury Works, a plant operated by Blue Circle Cement, UK, average seMce life is four years. The previ- ous vaive was only achieving seMce iife of between three and six months.

Aithough originaiiy developed three decades ago for use as an effective closure for pressure vessels on Clyde's advanced range of dense phase pneumatic conveying systems and process injection equipment, the Dome Valve has been soid as a stand- aione product since 1996.

I t has a wide range of appiications across a range of industries, including power, chemicals, mineral, iron and steel, and i t s abiiity t o cope with material tem- peratures from -2O'C to +480'C makes the Dome Vaive ideal for handling materials such as fly ash. Van actuator models are able t o cut through static columns of material up t o 2mm particie size or above in moving coiumns of powders, pastes and granular products such as coai. For static coiumns of material above 2mm particie size, cyiinder actuator Dome Vaives are highiy suitable.

FLSmidth Stacker and mfuimer system to hondfe sticky muteriafs To cope with non-free flowing moderately sticky materials or operations under tropi- cal conditions or during snowy or rainy

INTERNATIONAL CEMENT RMEW / DECEMBER 2001

STORAGE TECHNOLOGY

seasons, FLSmidth has developed a new reclaiming method, the so-called 'live harrow' concept.

FUmidth has a long and successful tradition of offering stacker and reclaimer systems. I n the 1960s, the company was among the pioneers i n launching such sys- tems for modern dry-process cement plants worldwide. However, the growing need for raw materiais has forced cement producen to abandon previous years' luxury of using only easy-to-handle, high-grade materials. As a result, they are now ficed with the challenge of using al1 the material quarried.

I n several cases, this has changed the conditions for extracting these matenals from the stores. For non-homogenising stores, such challenges are often overcome by using FLSmidth's portal scrapen or side scrapers which physically reclaim the mate- riais. For homogenising stores, on the other hand, the obvious choice i s an FLSmidth bucket chain excavator. This type of store continues to be the only one suitable for very sticky materials.

'Live humw conccpY The most commonly used homogenising stores are the longitudinal and the circular store with raking harrows mounted on the bridge reclaimer. These types of store are suitable for handling free-flowing or moderately sticky materials. However, to cope with non- free flowing moderately

sticky materials or operation under tropical conditions or during snowy or rainy sea- sons, a 'iive harrow' concept may be used. It features a system of motonsed scraper chain drag conveyors with scraper bars working in conjunction with an arrange- ment of stationary tooth racks. A system of ploughs collects the material a t the stock- pile base and feeds the bridge scraper blade conveyor system.

Temcor Temcor, the world's largest aluminium dome builder, has completed construction of a 374' diameter raw material storage dome for Lehigh Portland Cement Company's Union Bridge, Maryland plant. ,

Several options for the faciiity were considered, including steel and concrete. The Temcor aluminium dome was selected because of Temcor's vast experience in the

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bulk storage industry and because Temcor was aiso an economical choice. The inher- ent advantages a Temcor aluminium dome offers, include:

low maintenance long life span the relatively short design, manufacture

and erection time. The design, manufactunng and con-

struction of the dome were completed i n a fraction of the time required for other building types. The Lehigh dome was shipped to the site ready to assemble, and was erected with a small crew of 3-12 men, with a total construction time of only 6500 man-hours.

"Temcor is a professionai company," according to Lehigh's project area engineer responsible for the preblend dome. "The turnkey design, supply and construction of the preblend dome for our Union Bridge modernisation project came off safely, without a problem and on schedule. You can't ask for more than that."

The all-aluminium dome was designed with a conveyor opening that has a water- tight seal, doorframes, personnel access doors and skylights. The dome was erected using Temcor's unique and efficient centre tower erection method, erecting the dome from the centre outward. Workers assemble the frame on the ground, lifting the dome up as each ring is completed. On average, a Temcor aluminium dome is assembled using one-third of the man-hours required for conventional construction.

Temcor has become a prominent name in the bulk storage industry, with domes in service for cement plants, coa1 processing and storage, and other facilities requiring environmental protection. A Temcor all-alu-

minium dome i s virtually main- tenance-he, helping to keep operating costs down.

Temcor has been build- ing aluminium domes and other structures for more than 35 years and has more than 6000 installations throughout the world in industries as var- ied as water and wastewater treatment, petroleum and bulk

1 .. storage, and scientific i research. Temcor domes and

roof systems for architectural 1 applications are used in

places such as sports arenas, cruise terminais, planetari-

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and ums, U

churches more. n

( INTERNATIONAL CEMENT R M E W / DECEMBER 2001 >- E