As part of the modernisation program for the integrated steel mills of Lucchini Impianti S.p.A., Brescia, Italy, ThyssenKrupp EnCoke GmbH, Bochum, Germany, has completed two contracts, one for the reconstruction of coke oven batteries and gas treatment facilities at their Trieste works and the other for the hot repair of a coke oven battery and the modernisation of a pusher machine and a coal charging car at their Piombino works.

At the Trieste works (Servola S.p.A.) a new coke oven battery with 29 ovens featuring low-NOx COMBIFLAME® heating system and gas tight coke oven doors went into operation on 11.9.2000. It replaces two small batteries with 11 ovens each. The new Battery A has a coke capacity of 210,000 t/a and forms an integral unit together with Battery B, which was built and commissioned by ThyssenKrupp EnCoke in 1992.

The total coke capacity of the Trieste coke plant is now approx. 480,000 t/a which is sufficient to supply the blast furnaces with B.F. coke. The main aim of the investment, however, was the alimentation of coke oven gas to the new power plant installed in the Trieste works. In order to provide as much coke oven gas as possible to the power station the coke oven batteries are underfired by a rich gas composed of natural gas and blast furnace gas.

Related to the coke oven gas supply to the power station the modernisation program for the Trieste works comprised also the installation of a coke oven gas desulphurisation plant with a throughput of 16,000 Nm3 per hour. The plant was constructed according to the VACASULF® process of ThyssenKrupp EnCoke by which the H2S content in the coke oven gas is reduced to less than 150 mg/Nm3, thus permitting it to be burnt in the new power station and converted into electricity.

At the Piombino works in the 27-oven coke battery, which went into operation in 1970, major repairs were necessary in the refractory block which were carried out as hot repair. In order to improve the battery operation a coal charging car and a coke pushing machines were modernized, too.

ThyssenKrupp EnCoke has developed tailored solutions for all three modernisation projects enabling the customer to dramatically improve production and pollution control. Once again, ThyssenKrupp EnCoke has proved competence in the field of coke oven technology and demonstrated particular expertise in the repair and modernisation of existing plants.

Meanwhile, in Taranto Works of ILVA S.p.A. - RIVA Group, the first oven of No. 12 Battery was pushed on 27.10.2000 in the presence of executive board members of ILVA and ThyssenKrupp EnCoke GmbH, Bochum, Germany. The new No. 12 and the existing No. 11 Battery now form a state-of-the-art cokemaking facility for the production of 900,000 t/a high quality coke which is used in ILVA's large blast furnaces.

The new battery comprising 43 TWINFLUETM compound ovens with 6.5 m oven height and an effective volume of 40 m3 per oven produces 1,240 t/d (450,000 t/a) coke and has a coal throughput of 1,750 t/d. The plant was built turn-key by CARBOTECNICA S.r.l., a subsidiary of ThyssenKrupp EnCoke, and features also a number of ancillary facilities like a new quenching tower with breeze pond, a new pusher and a new coal charging car and a quenching locomotive. The existing door machine was revamped and equipped with state-of-the-art electrics.

The new battery is equipped with the CONTROLPRESS® battery bracing system, gas tight FLEXZED® coke oven doors and state-of-the-art emission control equipment. All essential process functions at Battery No.11 and 12 are monitored and controlled by the COKEMASTER® process control system. It provides automatic temperature control and optimizes the battery heat consumption.

The new pusher machine, charge car and coke quenching loco feature automatic equipment for machine spotting, oven identification and interlocking. Parking and maintenance bays for the coke oven servicing machines are also included in the total package. The existing coke side emission control system has been extended and serves now both Batteries No. 11 and 12.

Another part of the total scope of the expansion and modernization program was the installation of two new primary coolers including the required heat exchangers and pumps and a new H2S scrubber in the gas treatment plant.

The job was completed slightly ahead of schedule and within the budget.