The author deeply experienced that even under the condition of restoring the PC 325 cement standard in China as soon as possible, China's cement industry will face the current situation in Germany sooner or later.
One. Carbon emissions of China's cement industry
Carbon emissions from the cement industry account for 7.5% of the world's total anthropogenic carbon dioxide emissions, while in China it accounts for 13.75%. In order to fulfill China's solemn commitment to achieve "3060", the carbon reduction task of the cement industry is facing severe challenges. The cement industry is an important industry in China's goal of achieving carbon peak carbon neutrality, which has an overall impact. We must resolutely and satisfactorily accomplish this glorious and arduous historical mission.
In 2020, China's anthropogenic carbon dioxide emissions totaled 10.2 billion tons, cement output was 2.38 billion tons, clinker output was 1.58 billion tons, clinker coefficient CF 0.66, cement industry carbon dioxide emissions were 1.375 billion tons, and the carbon footprint of unit cement was 578 kgCO2/t.c.
Drawing on the experience and actual data of Germany and the European Union and other countries, starting from the cement industry's sense of mission of self-reliance and self-reliance in its own efforts to reduce carbon, there are seven effective carbon reduction methods and technical measures for the three major carbon emission sources of ordinary Portland cement in China. See table 1 for details (the same below).
Search and analyze the relevant data at home and abroad, according to the actual data of China's current cement carbon footprint of 578 kgCO2/t.c., the author conducted research analysis and prediction on the potential and effect of various carbon reduction technical measures in China's cement industry in the next 30 years (that is, between 2021 and 2050) (Table 1).
The so-called carbon reduction potential refers to the best level or theoretical limit value that may be reached by each carbon reduction index within the above-mentioned specified period. For example, items 4 to 7 of carbon reduction measures: TSR of 100%, clinker heat consumption of 650 kcal/kg.cl., cement electricity consumption of 70 kWh/t.c., and net waste heat generation of 36 kWh/t.c., etc. It can be seen that these carbon reduction measures have used the power of the "flood" and have almost exhausted. Calculations show that the carbon reduction effects of the 4th to 7th, that is, the carbon reduction amount of each item is 40, 38, 10 and 6 kgCO2/t.c respectively. This is the maximum amount of carbon reduction that can be contributed by various carbon reduction technical measures, totaling 94 kgCO2/t.c.
In fact, because the carbon footprint of cement is mainly derived from the process emissions brought in by raw materials, the main force of its carbon reduction will be borne by reducing the clinker coefficient CF, using less clinker; increasing the proportion of cement LCC and PC 32.5 cement consumption with low clinker content; and developing three carbon reduction measures such as increasing the proportion of SCM use of new low-carbon cementitious materials. The carbon reduction data for the first, second and third items are interrelated and mutually reinforcing. Therefore, its carbon reduction potential and effect (carbon reduction amount) are considered and calculated together. The current situation in China is roughly 0.66 CF, PO 32.5 cement consumption accounts for about 45%, LCC and SCM consumption account for about 0.5%. It is expected that by 2050, CF will be reduced to 0.56, the proportion of PC 32.5 cement and PO 32.5 cement will rise to more than 55%, and the proportion of PC 32.5 cement will rise to more than 6%. The carbon reduction capacity of such measures 1 to 3 can reach 128 kgCO2/t.c: The capacity of the seven carbon reduction measures totals 222 kgCO2/t.c: China's cement industry is expected to reach carbon neutrality by 2050.
Second, the importance of PC 32.5 cement to the cement industry to achieve carbon neutrality
Long-term practice at home and abroad has confirmed that PC 32.5 cement has three advantages over PO 32.5 cement: 1) the adaptability to various engineering needs is better, and the production process is convenient for appropriate adjustment of performance, which is conducive to application. 2) Different kinds of mixed materials can be used for different degrees of deep processing. Better stimulate the activity of various mixed materials. Play more of its partial substitution role in clinker. 3) After the use of mixed material deep processing technology and concrete admixture technology, the performance of C30 concrete prepared by PC 32.5 cement in all aspects is enough to compare with the same amount of PO 42.5 cement preparation. In this application area, PC 32.5 cement is better than PO 32.5 cement. However, it should be noted that PO 32.5 cement is also very suitable for some engineering applications, so the strategy of taking PC 32.5 cement as the main and PO 32.5 cement as a supplement is in line with the actual needs of China's projects.
The application of LCC and SCM in the European market today is roughly as follows. The so-called low clinker content cement LCC, the complete statement consists of two parts. First, the existing EU cement standards in recent years added EN 197 CEM II/C-M, CEM V, CEM VI and other 32.5 composite cement (equivalent to China's original PC 32.5 cement), its clinker coefficient CF can be as low as 0.31 ~ 0.49, the market share of about 22%. The other part is cement with a CF of 0.20 or less that is being vigorously pioneered and innovated, and is being experimentally developed.
In addition, the new low-carbon cement material SCM currently on the European market mainly includes: sulfur (iron) aluminum salt cement (GSA), high-Bailite low carbon cement, calcined clay LC3 cement, solidia cement made of calcium silicate (magnesium), Celitement cement made of calcium silicate and quartz, Porsa cement (BCSA), Aether low carbon cement, Geopolymers: geological cementitious material; and so on. In addition to the first three, there are a small number of applications (market share of about 1 to 2%). The rest are in the process of pioneering and innovating, and are in the early stages of research and development experiments. Of course, it is not excluded that there are also some new types and new varieties of SCM that may also appear. But in general, SCM to achieve practical application, such as a market share of about 10%, it is estimated that it may not be after 2030.
Facts show that since China launched a "campaign" to eliminate low-grade cement 7 to 8 years ago, the market has given a clear answer: this practice is not scientific and feasible! The author believes that we should reflect now, and it is time to correct the error and stop loss. The restoration must be made as soon as possible by the "amendment order" that has eliminated the PC 32.5 cement standard for many years.
At the same time, we should also vigorously develop the application of innovative LCC and SCM, and increase its dosage by more than 6%. In this way, the potential of Reducing Carbon Emissions from Cement Processes in China can be brought into play, and the comprehensive carbon reduction amount is about 128 kgCO2/t.c.
On the contrary, if China's cement industry still adheres to the so-called "cement high label, low label cement must be eliminated" proposition. Then, at that time, its CF value will not only be impossible to fall, but will rise above 0.70. The final effect is not to reduce carbon but to increase carbon! The difference between one in and one out actually invisibly increases the carbon reduction burden of nearly 200 kgCO2/t.c. to China's cement industry to achieve carbon neutrality. It goes without saying that the two outcomes of the two choices, the restoration of the PC 32.5 cement standard, have a decisive impact on the quality of China's cement industry to achieve carbon neutrality.
Today, China's cement industry should be able, and must make a correct judgment, when the opportunity to make a decision, correct the error and stop loss, can not be delayed any longer. For the long-term fundamental interests of China's entire cement industry, the author kindly appeals to the majority of people of insight to dispel their worries and relieve their shackles (if any), speak freely, and make their due contributions to the restoration of PC32.5 cement standards in China.
Third, suggestions on the layout of carbon reduction measures for China's cement industry
Germany and the COUNTRIES OF THE EUROPEAN Union, as well as the world-renowned established cement conglomerates Heidelberg, Lafarge-Holcim, Cemex, Votorantin, CRH, Italcementi, Buzzi-Unicem... Around 2012, after the commitment to carbon neutrality by 2050, a common medium-term goal was achieved in 2020. By 2030, the carbon footprint of their respective cements will be reduced to less than 475 kgCO2/t.c. If you count from 2000, it will be about 250 kgCO2/t .c.(725-475) in the first 30 years (2000-2030), and then 250 kgCO2/t.c in the next 20 years (2030-2050). Thus the carbon footprint of cement in 2050 will reach 225 kgCO2/t.c: around. At that time, after deducting the natural carbon sink and CCSU of 115 and 110 kgCO2/t.c., respectively, it is possible to achieve carbon neutrality.
After the practice of the first 20 years (2000~2020), it is expected that the carbon reduction of the first 250 kgCO2/t.c.(725-475) can be completed by the joint role of carbon reduction measures 1 to 6, and the last 250 kgCO2/t.c. (475-225) will have to rely more on the main role of carbon reduction measures 1 to 3, as shown in Figure 1.
Figure 1: Commitments and reduction measures of European and world-renowned cement companies to achieve carbon neutrality
It should be noted that Table 1 is based on the premise of restoring the PC 32.5 cement standard in China as soon as possible, and the carbon footprint of Cement in China is predicted to reach 356 kgCO2/t.c in 2050. This is not a small gap from the 225 kgCO2/t .c in Germany at that time. China still needs 1 to 3 carbon reduction measures to continue to work hard (it is best to reduce carbon by 100 kgCO2/t.c. or so) to make more contributions. Because China has taken a detour in these three measures in the past 10 years, it has been delayed for more than 10 years. In fact, our country has not yet got rid of the "pit" it has dug. The data on carbon reduction measures 1 to 3 in Table 1 are only the author's personal "good wishes". It seems a little sad to say. But I firmly believe that: respect for science, perseverance, China's cement industry will definitely embark on the right path of development.
According to the latest data of the German Cement Factory Federation VDZ, the average data of the production technical indicators of the German cement industry is roughly as follows: CF 0.68, 32.5 composite cement consumption accounts for about 23%, LCC and SCM consumption accounts for about 1 to 2%, TSR 72%, clinker heat consumption 780kcal/kg.cl., cement electricity consumption 90 kWh/t.c. They believe that the carbon reduction of the three technical measures of continuously improving TSR and reducing clinker heat consumption and cement electricity consumption can reach about 70 kgCO2/t.c. The factor of waste heat power generation is not considered, because its impact on carbon reduction is very small.
The Roadmap for Carbon Neutrality for the German Cement Industry, published by VDZ in November 2020, clearly states that the focus of post-2030 cement carbon reduction will be on process emissions of carbon dioxide. To reduce CF to 0.53, the proportion of 32.5 composite cement use to 45%, and the proportion of LCC and SCM to 10%. This will reduce the process emissions of CO2 by about 100 kgCO2/t.c. The high-quality realization of carbon neutrality in the cement industry is decisive.
After learning of the latest above-mentioned developments in Germany, it has once again given great inspiration and encouragement to our country. The author deeply experienced that even under the condition of restoring the PC 325 cement standard in China as soon as possible, China's cement industry will face the current situation in Germany sooner or later. The countermeasures they have adopted today are very worthy of our country's reference. This strengthens my confidence and determination to firmly recommend that China restore the PC 32.5 cement standard at an early date. It can even be said that restoring the PC 32.5 cement standard is an indispensable measure for China's cement industrial parks to achieve carbon neutrality. The old man's appeal from the bottom of his heart is a heart of good and bitterness, a heartfelt word, and a righteous deed! We kindly ask the national authorities and the Cement Standardization Technical Committee for understanding and support.
bibliography
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Cement Industry.March 2018
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Cement 2019 NO.11 p.1-4
3.VDZ:Carbon Neutral Roadmap for the German Cement Industry.
Nov.2020
4. Gao Changming: Analysis of carbon emission reduction path in international cement industry and future advanced cutting-edge technology direction and application.
Report at the International Carbon Emission Reduction Forum of China Building Materials Industry Federation2021.07.29.
A wave of the times with improving resource utilization and establishing and improving a green and low-carbon circular development economic system as the core is rolling in!
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