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The ETA cooler: your greenfield solution

Dipl. Ing Andre Vos1, Konstantinos Kouklidis2
1 Group Manager Clinker cooler, Claudius Peters Projects; 2 Plant Manager, Company Antea Cement SH.A.

Summary: In the article below Titan Cement and Claudius Peters examine together the low operating cost of the Titan ETA Cooler in Albania. This case study presents the argument that the determining purchase factor for greenfield cement pyro-lines should be the cooler with the lowest operating cost.

1 Greenfield kiln lines

In the purchasing decision for greenfield kiln lines, cement manufactures mainly look at the pyro-line suppliers that can supply the complete preheater – kiln – cooler system.  The operating costs of the kiln line are however mainly determined by the efficiency of the clinker cooler. Therefore the clinker cooler should be the driving force in the  selection of your kiln line, especially if you consider the total life cycle costs.

2 Titan project description

The main players in this project were first of all the Antea Cement Sh.A; part of the Titan group.

Titan is an independent multi-regional producer of cement and other related building materials. The Titan group is headquartered in Greece with plant locations in Europe, USA, Turkey and Egypt. The Antea Cement plant (Fig. 1) is located in Baka e Kuqe Albania. Furthermore, the main contractor for the kiln line was CBMI, a company belonging to the Sinoma group. The Sinoma group has received many of the pyro lines in the recent past with several Claudius Peters ETA Coolers. Claudius Peters has supplied an ETA 858 for 3300 tpd, which means a static inlet with 8 rows, a 5 lane wide cooler with 8 modules. The cooler is equipped with a roller crusher RB305- 3(4). The roller crusher has 3 rollers that stretch over the complete width of the cooler and is equipped with one blank that can be retrofitted with a 4th roller. The decision for the ETA cooler was mainly based on the low projected operating cost of the ETA Cooler. In the article below the operating results are examined that were actually achieved in Titan and compared with the equivalent value that would be reached with a traditional grate cooler.

3 Operation costs clinker cooler
3.1 Cooler availability
At the start of operation beginning in 2010 there were some problems at the Titan plant with the correct setup for the whole kiln-cooler system; this led to snowmen on the cooler static inlet. After some minor modifications to the HE-Module and some alterations to the setup of the kiln system the sweet spot was reached. One of the setup improvements was that the burner was pushed further into the kiln, which had a positive effect on the clinker stickiness and the cooling properties. Titan managed to operate the kiln from end of January 2010 till January 2011 without any cooler related kiln stop. The aerated lanes are filled with protective pebbles (Fig. 2); these ensure heat and wear protection. The air inlet is well tucked away under this pebble layer. Since wear and tear can not influence the air inlet, a constant air supply over time is ensured. The ETA cooler has matured; Titan reached an availability of 100 % over the above-mentioned time frame. With a traditional grate cooler an availability of approximately 99,5 % can be reached. Some downtime for a burned grate plates or damaged
hammers due to a red river must be considered. The high cooler availability results in additional production time!

3.2 Cooler efficiency
The design of the ETA cooler has taken into consideration the major problems that have plagued traditional clinker cooler, such as red-river, clinker segregation in fine and coarse grains etc. The process optimised aeration of the ETA cooler has the following features:ETA article - 1

– Small aeration fields on the HE-Module which ensures precise aeration in the clinker drop zone.
– Small chambers immediately after the HE-Module and only after 7 meters into the cooler, bigger chambers of 3.3 or 4.4 meters in length. The size of the chambers is equivalent to the hyperbole clinker cooling curve.
Small chambers in the steep start of cooling curve and bigger ones in the flat part.
– Controlled side aeration of the side lanes ensures actively influence of the side areas of the cooler which are the traditional red-river areas.
– Independent lane movement allows operation of each lane with a different stroke length. Normally the stroke length of the outer lanes is about 150 mm and the stroke length of the middle lanes is 250 mm.
These features combined, make the difference between the superb process performance of the ETA in comparison to a grate cooler and allow the ETA cooler to operate with a clinker bed of 0.8 to 1m without problems of air breakthroughs. In the case of Titan it was possible to reach a cooler efficiency of more than 76 % and this only at a recuperation air of 0.85 Nm³/kg clinker. The benefits for the costumer are clear; a high cooler efficiency
means a high recuperation air temperature and it is possible to operate the kiln with reduced fuel consumption. A difference of ca. 2 % in cooler efficiency, which is not unusual between an ETA cooler and a grate cooler, results in a reduction of the kiln heat consumption of more then 10 kcal/kg clinker. This means a huge reduction in the fuel bill, the high cooler efficiency is the main money-maker for the ETA Cooler.

3.3 Maintenance costs
ETA article - 2The almost wear free system of the ETA cooler; with its pebble filled lanes, leave only a few wear parts. The filter and sealing set of the hydraulic power unit (Fig. 3) and the last parts of the sealing system are such typical spare parts. With a traditional grate cooler the grate- and side plates are in direct contact with the clinker, and must be replaced over time. This takes a huge chunk out of the maintenance budget of any clinker producer. The design of the ETA Cooler ensures minimal maintenance cost over time.

3.4 Power consumption of the cooler
One argument that some customers have against the ETA cooler is the higher power consumption. Part of the higher power consumption can be traced back to the higher clinker bed used; 0.8 to 1m instead of the usual 0,6m for the normal grate cooler. This results in a higher pressure drop, so higher power consumption of the cooling air fans. One must argue however that the advantages of a higher clinker bed such as a higher cooler efficiency and more efficient cooling with therefore less cooling air outweigh the disadvantage of slightly increased power consumption. However at Claudius Peters the concern about the power consumption led to the development of new aerated lanes with a clearly reduced pressure drop. The pressure drop over the lanes filled with gravel is now ca. 10 mbar which is only slightly above the pressure drop of a slot plate in a grate cooler. The advantages of a wear free system, which the ETA cooler is, outweigh the slightly increased power consumption. Many people stop here in their comparison for a cooler investment decision; however the ETA cooler has some additional benefits.

3.5 Exhaust air volume
Due to the reduced amount of air that the ETA cooler uses, thanks to the higher clinker bed and more efficient cooling, the exhaust air volume is smaller. This results in a reduced power consumption of the fan for the exhaust air. This item alone completely makes up for the disadvantage of the power consumption of the cooling air fans as mentioned under item 4. The filter system of an ETA cooler can be sized substantially smaller compared to that of a grate cooler. This gives a capital investment advantage for your greenfield pyro line.

3.6 Combustion gas volume
Finally the last issue in the comparison of the operation costs is the combustion gas volume. In combination with the ETA cooler the kiln uses less fuel. We have considered the monetary influence of this under item 2, however the side effect is that less combustion gases are generated which means that the preheater ID fan uses less power.

4 Total lifecycle costs
The low operation costs of the ETA cooler gives it a clear advantage compared to a traditional grate cooler if we consider the total life cycle costs. The total life cycle costs are the sum of the investment costs, operation and maintenance costs etc. calculated over the expected life span of the equipment. With a cooler lifetime of 25 to 30 years the investment costs have only a minor impact of on the total life cycle cost. The cooler with the lowest operation and maintenance costs is clearly one step ahead. The decision of Titan to purchase the pyro-line from a Chinese manufacturer with specific equipment such as the ETA cooler from a first class cooler supplier like Claudius Peters makes therefore economic sense.ETA article - 3

5 ETA semi – modular
Against this background, we have further developed the ETA Cooler. Especially for new greenfield pyro-lines we have modified our ETA Cooler design to allow maximum customer supply. The parts that determine the clinker cooling process such as the HE-Module grate plates and aeration box, aerated lanes and sealings, roller units and hydraulic grate drive will be complete the Claudius Peters supply. This ensures highest fabrication precision at proven manufacturing plants. In this case (Fig. 4) the simple steel structure such as the cooler upper part and also the cooler lower side walls and partition walls are customer supply. The customer will manufacture these parts according to Claudius Peters workshop drawings. For important parts such as the lower side walls and partition walls, Claudius Peters sends an erection engineer to the workshop of the customer to ensure the  quality and main dimensions. The erection time of the semi-modular ETA cooler is several weeks longer but this is not critical for greenfield plants.

6 Conclusion
So far Claudius Peters has sold 48 ETA coolers of which 26 are for greenfield plants. 14 of the ETA coolers for greenfield plants are in the semi-modular cooler design. With the increased focus on energy conservation and the consideration of total life cycle costs the clinker cooler will be of the utmost importance in the purchasing decision for a clinker pyro line. Equipment that determines the main share of the operating cost, such as the cooler, will have the great importance in the purchasing decision. The Titan plant in Albania is one example of an ETA cooler in a greenfield plant. The combination of a Chinese main contractor with Claudius Peters as the cooler supplier worked out very well.

ZKG_05-2011_Vos_Titan

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