Environmental Sustainability in the VET System: a Powerful Tool for the Future Project No. 2016-1-IT01-KA202-005387
Advanced Didactic Module 1.2: Didactic manual on “Low-Carbon Economy and Cement Production”
Developed by: INSTITUTE OF CHEMICAL METHODOLOGIES OF NATIONAL RESEARCH COUNCIL IMC-CNR
Authors: Piero Ciccioli (firstname.lastname@example.org) Pietro Ragni (email@example.com)
The European Commission support for the production of this publication does not constitute an endorsement of the contents which reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.
1 Project No. 2016-1-IT01-KA202-005387
2 Project No. 2016-1-IT01-KA202-005387
1 â€“ Reducing CO2 emission
Notes: Relate these contents to slides 2 and 3 of the didactic presentation in PowerPoint. Here the teacher/trainer can add other notes and reminders that could be helpful to structure the lesson.
Reducing CO2 emission is of paramount importance to mitigate the Earth climate changes caused by the progressive increase of greenhouse gases (GHG) in the atmosphere that has been observed since the beginning the Industrial Era. It is well established that CO2 produces an increase in the temperature of the atmosphere and the oceans. These effects, although small, can dramatically affect the complex equilibria controlling the Earth climate. For this reason, international agreements, such as the Kyoto Protocol, were developed to commit state parties to reduce GHG emissions, based on the scientific consensus that global warming is actually occurring and it is likely that human-made (anthropogenic) CO2 emission plays an important role in this process.
In order to meet the target defined by the Kyoto Protocol, the EU Emission Trading System has been introduced in the European Union Member States. This policy set a cap on the total amount of CO2 and other selected GHG that can be emitted by different sectors of human activities. Within this cap, 3 Project No. 2016-1-IT01-KA202-005387
Points to be stressed: Here the teacher/trainer can take note of the main concepts that he/she wants to stress during the lessons. Key message: Here the teacher/trainer can take note of the key messages that he/she wants to transmit to the students/learners. Example: Here the teacher trainer can draft one or more examples that he/she finds useful to better explain the concepts introduced in the corresponding part of the didactic manual.
companies receive or buy emission allowances that they can trade with one another as needed. They can also buy limited amounts of international credits from emission-saving projects. For what CO2 emission is concerned, the sectors regulated by EU ETS are power and heat generation, commercial aviation and energy-intensive industry sectors including oil refineries, steel works, production of iron, aluminum, metals, cement, lime, glass, ceramics, pulp, paper, cardboard, acids and bulk organic chemicals.
Notes: Relate these contents to slides 4 and 5 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
Sectors not covered by the EU ETS are waste management, agricultural production, energy supply, ground transportation and building industry. The European Effort Sharing Regulation (ESR) sets the non-ETS emissions reduction targets for each EU Member State based on its wealth, measured by its GDP per capita. Each government is, thus, committed to develop adequate policy actions aimed at mitigating emission coming from non-ETS sectors, in order to meet the national GHG reduction targets. Such policies include, for example, widespread promotion of good practices in waste disposal strategies and subsidization of renewable energy sources in order to stimulate a significant increase in the adoption of green technologies for electricity production. While, in most cases, national policies succeeded in meeting the emission reduction targets set for the non-ETS sectors, the situation for the ETS sectors is still problematic. Despite being hailed as the flagship of European climate policy, the EU ETS has failed to fully deliver its objectives. A weak reduction target and the massive use of international offsets have led to the buildup of an enormous surplus of 4 Project No. 2016-1-IT01-KA202-005387
emission allowances. Therefore, the price for allowances has dropped so much that it no longer drives change. While EU decision makers are currently discussing ETS reforms for the period 2021-2030, urgent actions have to be undertaken to mitigate the GHG emissions arising from those ETS production sectors that are most impactful on the environment. This is particularly needed for the CO2 emission, that is, by far, the most abundant one (ca. 80% of the whole GHG anthropogenic emissions). CO2 emission coming from the ETS sectors account for ca. 45% of the total emission of this greenhouse gas in Europe. This is mainly due to the fact that the majority of high carbon industries falls in the ETS category. Among the most energyintensive productions, the process for the manufacturing of cement used for making concretes widely utilized in building industry is one of the most important. It has been estimated, indeed, that nearly 1 ton of CO2 is emitted for each ton of cement produced. It is, thus, not a coincidence that those EU Member States exhibiting the highest shares of CO2 emission from ETS sectors are also the major producers of cement in Europe. For example, Germany has the highest share of CO2 coming from ETS sectors in Europe (25%) and is also the major European cement producer (with an estimated production of 32 million tons per year).
2 – CO2 emission from cement production The direct CO2 emission arising from cement manufacturing is produced by the process needed to obtain clinker, which is the main constituent of common cement. It is an hard substance that is ground with a small amount of gypsum to make that fine powder called ‘ordinary Portland cement’, commonly used to produce mortars and concrete. Clinker is obtained by heating limestone (calcium carbonate) with other materials (usually clays) up to 1450 °C in a kiln. During this process (called calcination) a molecule of CO2 is released by each molecule of calcium carbonate to form calcium oxide, which then chemically combines with the other materials that have been included in the mixture to give rise to clinker. 5 Project No. 2016-1-IT01-KA202-005387
Notes: Relate these contents to slides 5, 6 and 7 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
It has been estimated that CO2 produced through calcination process accounts for about 50% of the total CO2 produced by cement manufacturing.
Notes: Relate these contents to slides 7, 8 and 9 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
While calcination of limestone releases CO2 directly, the indirect CO2 emission arises from those actions needed to keep the cement production plants in operation. Kilns used to produce clinker are usually heated by coal, natural gas or oil, and the combustion of these fuels produces additional CO2 emissions. The combustion of fossil fuels needed to heat kilns contributes for about 40% of the total CO2 emitted by cement manufacturing. The electricity used to power additional plant machinery along with the transportation of cement to distribution hubs and end users represent another source of indirect emission, that account for about 5-10% of the total CO2 emission produced by cement industry.
Besides CO2 emission, cement production generates other significant environmental impacts. The quarrying of raw materials needed to obtain clinker, such as limestone and clays, produces severe alteration of landscape, soil depletion and removal of autochthonous plants. Moreover, the extraction and industrial processing of these rock materials progressively deplete a non-renewable natural resource, ultimately leading to loss of geodiversity. In order to effectively reduce the CO2 emission and the 6 Project No. 2016-1-IT01-KA202-005387
a function of the type and the quantity of SCM used to replace clinker. By taking in account these latter parameters, the European cement standard EN 197-1 officially defines five types of cements, with three possible classes of strength. The five type of cements (called CEM I, II, III, IV, V) are defined, basically, by the type and the amount of SCM used in their composition. The three strength classes (namely 32,5 – 42,5 – 52,5) are defined by the strength reached by the cement after 28 days of hardening, that is measured by means of a standard pressure test.
Points to be stressed: Key message: Example:
CEM I - Portland cements
CEM I are ordinary Portland cements with a content of clinker higher than 95% and a variable amount (from 0% to ca. 5%) of SCM, usually blast furnace slug. Disadvantages: CEM I are the high-carbon cements by definition. The production of CEM I should be, thus, diminished, by favoring a more widespread use of blended cements with higher substitution rates of clinker. Advantages: CEM I cements easily satisfy the requirements of the two cement classes of higher strengths (52,5 and 42,5), they are, thus, suitable for several applications where cement is commonly used, such as concrete for vibropressed precast (e.g. hard paving), concrete for monolithic structures and elements, cement and cement-lime mortars, standard reinforced concrete for building purposes. CEM II – Portland-composite cements
CEM II are called Portland-composite cements, they have a content of clinker ranging from 95% to 65%, thus corresponding to a content of SCM ranging from 5% to 25%. 7 Project No. 2016-1-IT01-KA202-005387
Notes: Relate these contents to slides 12 and 13 of the didactic presentation in PowerPoint.
Disadvantages: the production of CEM V implies the contemporary availability in a given area of two different types of SCM in large quantities, the occurrence of this condition may not be met frequently. Advantages: because of their ‘hybrid’ nature, CEM V cements are very versatile, they can be used, thus, in the construction of dams and flumes treatment plants, and for the production of mass concrete casting, paving concrete, etc.. Why blended cements are a viable solution? Economic advantages: The large majority of SCM are byproducts of industrial processes, they are, thus, much cheaper than clinker; SCM usually do not need expensive additional treatments to be used in cement manufacturing, their preparation is, thus, a lot cheaper than the production of clinker; CO2 emission is reduced just by substituting main components of cement, no expensive adjustments to the production plants are needed. Environment al advantages: Both direct and indirect CO2 emissions originated by cement manufacturing process are mitigated, as less CO2 is produced directly by the calcination of limestone and less CO2 is emitted indirectly to heat the kilns, because lower temperature or no thermal treatments are needed to prepare SCM, meaning that less fossil fuels are used for the manufacturing process; A non-renewable resource (limestone) is less exploited and, at the same time, different industrial wastes (SCM) are recovered and virtuously recycled.
4 - New frontiers: Carbon negative cements Besides the EU normed blended cements, cement companies and research centers are currently developing new materials that could fully replace limestone/clinker. One of the pioneering companies in this field was Novacem, that proposed in 2005 a prototype of carbon negative cement. Rather than using limestone, Novacem used magnesium silicates, that are not only a more exploitable 8 Project No. 2016-1-IT01-KA202-005387
Notes: Relate these contents to slides 17, 18 and 19 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
resource, being among the more abundant minerals on Earth crust, but also do not contain carbon, so no CO2 is emitted, and the heating temperature needed to treat the raw material is half of that required to convert limestone into clinker. Another company, Calera, tried to make calcium carbonate from seawater mixed with CO2 coming from power plants, in order to obtain an almost neutral carbon cycle. CarbonCure is developing a technology that injects CO2 captured from industrial processes into Portland cement, thus improving materialâ€™s strength and recycling CO2 at the same time. However, none of these technologies is still ready for mass market. Research bodies are exploring, instead, the potential applications as sustainable alternative to traditional cements that can be offered by geopolymers. These are inorganic cementitious binders obtained starting from aluminum and silica based materials. The main advantages coming from the use of geoplymers are similar to those of the carbon negative cement developed by Novacem. The raw materials used in this case are clays (usually kaolinite), that do not contain carbon and need much lower temperatures (ca. 650 Â°C) to be converted in the mineral form (metakaolinite) needed for the production of geopolymers.
The challenge for these rising technology lies in the price and the required reliability. The industrial production of geopolymers implies to change completely both the design of cement production plants both the construction methods that should be used in building sites. Moreover, the performances of geopolymers in building applications still need to be further investigated, in order to certify an adequate reliability.
5 â€“ Complementary approaches Other than mitigating CO2 emission by using decarbonized materials as substitutive of clinker, different complementary approaches can be followed to make the whole cement production chain further greener. Instead of focusing on raw materials, these actions are mainly addressed towards cement 9 Project No. 2016-1-IT01-KA202-005387
Notes: Relate these contents to slides 19, 20 and 21 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
6 â€“ The case study: COLACEM S.p.A.
Notes: Relate these contents to slides 25 and 26 of the didactic presentation in PowerPoint. Points to be stressed: Key message: Example:
Colacem S.p.A. is a leading cement producer worldwide and the third major market player in Italy, a Country that actually is one of the EU major emitter of CO2 originated by ETS sectors, as well as the second major producer of cement in the European Union (with an estimated production of 23 million tons per year). In this regard, Colacem S.p.A. represents a virtuous example, as the company is characterized by a vision strongly oriented towards environmental sustainability, that is put into practice by means of state-of-the-art expertise in sustainable management, technical innovation, design and implementation of cement production facilities. The Colacem case study is paradigmatic of the fact that the promotion of environmental sustainability can be an added value for companies operating in the high carbon industry sector and it can also bring to the enterprises a competitive advantage, because this approach combines environmental benefits with business model innovation. Materials By following the blended cements approach, Colacem partly replaces limestone and clinker with non-hazardous decarbonized byproducts of different industrial activities. For instance, the company partly replaces limestone for the production of clinker with ashes derived from various combustion processes, generating a significant reduction of the CO2 emission originated by calcination process. Colacem uses also SCM in their cement compositions to partially replace clinker. Especially fly ashes derived from coal combustion processes and pozzolans are widely used. In the last year, the non-hazardous byproducts used by Colacem as raw materials and SCM amount to about 386.000 tons, accounting for about 6,5% 10 Project No. 2016-1-IT01-KA202-005387