REFRACTORY. The Benefits of Energy Efficiency and Environmental Friendliness. Giuliano Copetti Prague, June 15th 2016

Transcription

1 REFRACTORY The Benefits of Energy Efficiency and Environmental Friendliness Giuliano Copetti Prague, June 15th

2 Since the very beginning of the industrial era, different aims and strives have moved the production technologies towards new horizons and objectives: Mirroring the needs and the evolution of the society Adopting the new emerging ways of thinking of the populations Following the changes and the challenges of the time. 2

3 Not proper as a substitution of the previous and original social and economical values, but rather as their completion and adaptation to a new vision of the world, concepts like Production Profit Gain Expansion Growth Volumes Markets 3

4 have been often and often paired and accompanied by new ones such as: Health Safety Environment Resources Sustainability Responsibility 4

5 Having spread all over the industrial world, this new concepts have been, and still continuously are: Touching Influencing Redefining also the world of refractory, and especially its very specific branch of monolithic products. 5

6 So, now, question is: What are the major actual trends influencing monolithic refractories applications? 6

7 Without being able to present a fully exhausting list, following features represent some of the most actual trend for this peculiar branch of the refractory industry. 7

8 1. Shortening and optimization of the delivery time 2. Reduction of warehouse stocks. Sudden decisions from end customer s side often require flexible and short delivery times. Planning is suitable to change, and so has to be the whole supply chain. Often refractory company are required to act as just-in-time warehouses for their final customers. If compared to the bricks production (considering the different shapes needed for any single project), these has always been advantages for monolithic refractory. Nevertheless, further solutions have to be found to keep on enhancing these features (e.g. new plant layout solutions to increase flexibility in the production process). 8

9 3. Diversification. How to match products to different application features. Products specifically designed for different applications. With or without modifying the installation technology. Research & Development, in one word. Again and again. 9

10 4. Waste reduction. Zero waste is not a reachable target, of course. But it has to be a target to follow and follow. Since, more than in the past, and more and more in the future, waste means money. Lot of money. Lost money. The monolithic concept of endless lining, repair just what is consumed, offers the strongest possibility to reduce the generation of wasted materials from the end utilizers production cycle. Recycling is also a way. But if uncontrolled 10

11 5. Automatizing. How to enhance installation speed. And safety. Where possible, monolithic refractories offer the possibility to automatize or, at least, mechanize the installation activity. A fully unreachable result for other types of refractory products. Saving time. Since no need to build/dismantle complex holding structures anymore Saving money. Since time of intervention is strongly reduced, and after installation the plant is immediately suitable to operate. Protecting people. Because safety is not an issue. Not at all. 11

12 6. Energy saving Fast curing materials and high insulation properties gives strong support to energy savings, acting mostly in the same directions: Less curing time means less fuel consumption. Higher insulating capability means less thermal dispersion. Additionally, protected by materials with high insulation properties, the refractory layers work under conditions of better thermal uniformity (as well as mechanical one). As a consequence, less stress induced by thermal variations, reduced possibility of fractures and material losses 12

13 A case study of fast curing materials: Seven Refractories Cement Free Castable. 13

14 The water added to a castable is distributed in two different portions: the so-called Imbibition Water used to wet the whole range of RM grains, and to fill the open porosity. the so-called Reaction Water needed to react with HAC (High Alumina Cement), forming the hydrated phases. 14

15 During the heating-up process, the imbibition water evaporates, and its complete elimination is a gradual process spread along a rather large time window, at a (theoretical) temperature not higher than 100 C, without any modification of the castable structure. The width of this time window, necessary to allow all the contained imbibition water to reach the surface and eventually evaporate, strongly depends upon the thickness of the installed castable layer, and therefore strongly impacts the duration of the heating-up procedure. 15

16 As temperature further increases, once the different hydrated phases reach their own decomposition temperatures, the corresponding water release becomes a sudden and rather violent phenomenon. Most of these dehydrations take place between 450 and 550 C, and this reaction water is released in a more traumatic way (than imbibition water ): it is like water getting free at a temperature that only allows the existence of overheated vapor, with higher specific volume than the steam at 100 C. The practical result is that this second step of water elimination is by far the most critical one, and almost all damages are 16 experienced there.

17 An alternative bonding system can be achieved in several ways. OneoftheseclassesofNo Cement Castable (NCC) is based on the utilization of Liquid Colloidal Silica solutions (LCS). In this case, the complete elimination of the cement means the substitution of the hydrated phases with a sol-gel transition reaction, to guarantee the setting phenomenon. 17

18 As first result, it definitely smoothens the dependency of the mechanical characteristics from the temperature. Therefore LCS are very reliable and performing in comparison to the different types of hydraulic bonded cement based refractory castables. But the main achievement can be considered the strong reduction in the time (and energy) needed to complete the heating-up process. 18

19 In fact, in LCS, all the water in the system behaves as Imbibition Water : no cement no hydration of CA phases no water included in the structural network no water release at the critical T of C. All the water has already left the refractory mass after vaporization around 100 C. 19

20 Therefore LCS, when especially linked to the curing and heating-up procedures to be applied, are products specifically suitable for all the applications where time represents a leading factor in the general economy of the required performance. 20

21 21

22 Heating-up time reduction derives from: the reduced amount of water addition (instead of pure water there is a water solution). the complete water release taking place around 100 C (without rapid and violent residual water release over 400 C, with consequent potential strong damages of the casted refractory lining). 22

23 Comparison between theoretical heating-up curves: RC LCC ULCC HEATING CURVE SCHEMATIC NCC* HEATING CURVE SCHEMATIC HOURS: HOURS: C 800 C TEMPERATURE 400 C 450 TEMPERATURE 400 C C 100 C 20 C C LCC NCC - LCS 23

24 Referring to application: LCS casting technology is fully consolidated and widely accepted in the several refractory application fields. Other LCS application technologies still present wide exploration possibilities. Among them, LCS shot-creting technology is maybe the one that seems to show the largest and most promising expectations of success in the shortmedium period of time. 24

25 9. Environment. Really a peculiar and specific issue? We have already mentioned the endless lining, with the consequent waste reduction capability. Same for the fuel reduction, due to the use of fast curing and high insulating products, that also helps in the CO2 emission reduction. Can we call monolithic refractory environmentally friendly? For sure, they are among the refractory products the closest one to the suistanable economy... 25

26 10. Health and Safety. The human being, above all. Some peculiar raw material (e.g. the spinel-containing ones) has made possible to give up the utilization of Cr derivatives (such as Cr2O3 or Chromite) in the refractory formulation. Performances have been kept at comparable levels, while the exposition of producers and utilizers workforce to such toxic components has been almost eliminated. 26

27 Better and better performing products for purging plugs and sliding gates have drastically reduced their need of substitution, thus limiting human intervention under heavy operating conditions. As already mentioned, particular materials and technologies have made possible repair intervention on blast furnaces from outside, by means of remotely operated equipment. Potential risks and danger exposures of the people otherwise involved have been therefore strongly reduced. To be noted that an intervention in a Blast Furnace form inside can be considered as a typical example of Confined Space Entry 27

28 For the taphole clay production, it is needless to mention the advantage, in terms of health and safety, of having developed products with low (if not even without ) Polycyclic Aromatic Hydrocarbons content. The move from the old-fashioned tar-bonded taphole clays, to the actual resin-bonded products, represents one of the most important steps of the refractory industry towards ensuring clean environment, health conditions and full compliance with the most recent safety regulations. 28

29 A case study of environmentally friendly refractories: Seven Refractories Green Blast Furnace Taphole Clay 29

30 The main Seven s concept for THC is that of a: Continuously Ongoing Development Path 30

31 At first, a Consolidated System applied: for RAW MATERIALS and LAB CONTROLS: Raw material: selection / characterization / control / acceptance. Controls and analysis: internal / external 31

32 for PRODUCTION: STS - Seven Traceability System. Tolerance control on dry mixing. Addition of liquids: quantity control, tolerances management, temperature control, seasonal adjustment. Workability control: frequency, time intervals, acceptance procedure. Workability measurement devices management. 32

33 for DELIVERY and CUSTOMER SERVICE: Temperature recording (data logging) during shipment and/or transportation. Customer support during trials. 33

34 The Consolidated System is coupled with a System Development, which applies working: on the STRUCTURE: Substitution of tar with resins to achieve an environmental and healthy friendly product. Continuous development of different kind of resins to adjust the rates of setting inside of the taphole. 34

35 ...on the ADDITIVES: Introduction of metallic elements able to form carbide bindings inside the sintered structure: Me + C > MeC Utilization of carbon black as well as activated carbons to facilitate the formation of MeC. Utilization of Nitrides, Azides and Borides to enhance sintering processes due to their anti-oxidization effect. 35

36 on the IDEAS Introduction of Ti Oxides of different purities and in different percentages, with the aim of using THC also as a Ti-carrier, to intervene against localised BF hearth sidewalls consumption. 36

37 And, based on this Continuously Ongoing Development Path, Seven Refractories has been able to achieve 37

38 the most ENVIRONMENTALLY FRIENDLY tap hole clay now available on the market. 38

39 characterized by having the LOWEST EMISSION LEVEL of POLYCYCLIC AROMATIC HYDROCARBONS (PAH) achievable so far! 39

40 25,000 COMPETITOR PRODUCTS WITH TAR ANALYSIS OF POTENTIALLY HARMFUL TOTAL USEPA 16 PAHs ppm 20,000 15,000 10,000 20, , , , , , ,000 6, , Competitor 1 Competitor 2 Competitor 3 Competitor 4 Competitor 5 Competitor 6 Competitor 7 Competitor 8 LOWEST PAH VALUE: 5740 ppm 40

41 25,000 COMPETITOR PRODUCTS WITH RESIN ANALYSIS OF POTENTIALLY HARMFUL TOTAL USEPA 16 PAHs ppm 20,000 15,000 10,000 HIGHEST VALUE: 114 ppm 5, Competitor 9 Competitor 10 Competitor 11 Competitor 12 Competitor 13 Competitor 14 Competitor 15 41

42 PRODUCTS WITH RESIN from acceptable to GREEN Competitor 9 Competitor 10 ppm Competitor 11 Competitor 12 Competitor 13 Competitor 14 Competitor 15 Seven Tap 200 Seven Tap 300 Seven Tap 375 Seven Tap 055 PL

43 THANK YOU 43