It is unreasonable to include ready-mixed concrete and cement products in the "two high" projects.

On May 31st, 221, the Ministry of Ecology and Environment issued the Guiding Opinions on Strengthening the Prevention and Control of Eco-environment Source of Construction Projects with High Energy Consumption and High Emission, which made it clear that the "two high" projects were temporarily counted according to six industry categories, such as coal, electricity, petrochemical, chemical, steel, nonferrous metal smelting and building materials. If there are clear provisions for the countries within the scope of "two high", those provisions shall prevail. On September 11th, 221, the National Development and Reform Commission (NDRC) issued the Plan for Improving the Dual Control Degree of Energy Consumption Intensity and Total Amount, which proposed that the NDRC and relevant departments should strengthen the window guidance for the "two high" (high energy consumption and high emission) projects with an additional energy consumption of 5, tons of standard coal and above. For the "two high" projects with an additional energy consumption of less than 5, tons of standard coal, all regions will strengthen management and strictly control according to the objectives and tasks of dual control of energy consumption. Although the state has issued some restrictive policies on the development of the "two high" projects, the specific projects with high energy consumption and high emissions in the "two high" industries have not been clearly defined.

on October 2, 221, the Guangdong provincial development and reform commission issued the implementation plan for resolutely curbing the blind development of the "two high" projects in Guangdong province (hereinafter referred to as the "implementation plan"). The "Implementation Plan" tentatively defines the scope of the "two high" projects as projects in eight industries, including coal power, petrochemical, chemical, steel, non-ferrous metals, building materials, coal chemical and coking, with an annual comprehensive energy consumption of more than 1, tons of standard coal; Ready-mixed concrete and cement products are classified as high-energy consumption and high-emission products or processes in the "two high" industries, and their new projects shall be implemented according to the "Guidelines for the Management of Newly-built" two high "projects (annex to the Implementation Plan).

The Implementation Plan issued by Guangdong Province is an important measure to implement the decision-making arrangements of the CPC Central Committee and the State Council, and fully promote the work of peak carbon dioxide emissions, carbon neutrality and energy consumption control in Guangdong Province, which is necessary. However, we believe that it is unreasonable to list ready-mixed concrete and cement products as high energy consumption and high emission products or processes in the "two high" industries.

I. Energy consumption of ready-mixed concrete and cement products

1. Ready-mixed concrete

In the national mandatory standard "Energy Consumption Limit of Ready-mixed Concrete Unit Product" (GB36888—218), The energy consumption limit grade of ready-mixed concrete unit product is as follows:

Table 1 Energy consumption limit grade of ready-mixed concrete unit product

At present, the annual output of most mixing stations in China is about 5, m3. If calculated according to the second-level energy consumption limit (the admittance value of new or expanded projects), its production energy consumption is about 35 tons of standard coal/year, and its transportation energy consumption is about 1325 tons of standard coal/year.

therefore, even if the transportation energy consumption of ready-mixed concrete is included, the energy consumption of ready-mixed concrete is far from the scope of the "two high" project in the Implementation Plan-the annual comprehensive energy consumption is more than 1, tons of standard coal.

2. cement products

in the national mandatory standard "energy consumption limit of cement products per unit product" (GB38263—219), the energy consumption limit grade of cement products per unit product (concrete per cubic meter) is as follows:

Table 2 Energy consumption limit grade of cement products per unit product

Note: 1.

2. The unit product access value of cement products of newly-built or expanded cement products enterprises should not be greater than Grade 2 in the table.

taking calcium silicate board products as an example, the annual output of domestic calcium silicate board production lines is generally 5 million m2. If calculated according to the 2-level energy consumption limit (admission value of new or expanded projects), its comprehensive energy consumption is about 2,79 tons of standard coal/year.

taking precast concrete pile products as an example, the annual output of domestic precast concrete pile production lines is generally 1.5 million meters. If calculated according to the second-level energy consumption limit (the admittance value of new or expanded projects), its comprehensive energy consumption is about 5,24 tons of standard coal/year.

at present, there is no national standard for energy consumption of prefabricated concrete members in prefabricated buildings. According to the Shanghai local standard DB31/192—218 "Technical Requirements for Energy Consumption of Prefabricated Concrete Components in Assembled Buildings", the comprehensive energy consumption index value of existing prefabricated concrete components manufacturing enterprises is 5.5kgce/m3, and the comprehensive energy consumption index value of existing enterprises and new enterprises is 25.2kgce/m3. The output of prefabricated building precast concrete production line is generally 3,-5, m3/ year. According to the above energy consumption standard access value, its comprehensive energy consumption is about 1,26 tons of standard coal/year.

The annual comprehensive energy consumption of new projects is closely related to the project scale. It should be noted that the above energy consumption data is calculated according to the common production line scale of the project and only according to the highest limit of relevant mandatory energy consumption standards, and the actual energy consumption is far less than this value. In recent years, the technological progress of cement products enterprises is changing with each passing day, and the industrialized manufacturing mode is mature. With the innovation of process technology and manufacturing technology, product manufacturing is gradually developing in the direction of intelligence, energy saving and low carbonization. Take Jianhua Building Materials, the largest cement product manufacturer in China, as an example. In recent years, Jianhua Building Materials has continuously carried out R&D and innovation in the manufacturing process of cement products, and a variety of new automation equipment, energy-saving equipment and intelligent systems have been put into the manufacturing process one after another, such as automatic pumping concrete technology, automatic mold handling equipment and prestressed automatic tensioning system, which have improved the production efficiency of prefabricated components by more than 2%. The intermediate frequency energy-saving technology of roller welding machine can save more than 3% power consumption, the maintenance waste heat recycling system can save more than 13% power consumption, and the autoclaving-free preparation technology of precast piles can reduce the production energy consumption by more than 6%. Through the application of advanced technologies, equipment and systems, the comprehensive energy consumption (average value) of the unit product of Jianhua building materials concrete precast piles has decreased from 49kgce/m3 in 29 to 3kgce/m3 in 22, and 73% of the production bases have reached the first-class energy consumption standard of precast concrete piles, with the lowest value of only 9.5kgce/m3.

It can be seen that the cement products project is far from the "two high" project standard in the Implementation Plan-the annual comprehensive energy consumption is more than 1, tons of standard coal. Therefore, it is unreasonable to restrict cement products in the "two high" projects.

II. Emissions of ready-mixed concrete and cement products

1. Ready-mixed concrete

Ready-mixed concrete is the embodiment of technological progress and green development of the industry. The development from scattered mixing in the past to intensive and industrial production at present not only improves and guarantees the quality of concrete products, but also strictly controls the discharge of "three wastes". In fact, at present, domestic ready-mixed concrete mixing stations, especially newly-built stations, mostly adopt large-scale and advanced technology and equipment, and implement professional production management, with high equipment utilization rate, accurate measurement, low material consumption, high production efficiency, good product quality and little environmental pollution. In recent years, with the continuous promotion of national green development and environmental protection policies, ready-mixed concrete enterprises have basically completed the equipment transformation and technical upgrading of green and clean production. The vast majority of concrete enterprises have built fully-enclosed indoor stockyards with automatic induction spray dust removal systems, fully-enclosed mixing buildings with large dust removal devices, fully-enclosed material conveying systems, comprehensive sewage treatment and waste concrete recycling systems, etc., which technically ensure that the production process basically achieves zero emission.

2. Cement products

Developing cement products and improving prefabrication rate and assembly rate is an important way to realize the goal of "double carbon" in building materials industry as soon as possible.

precast concrete members are one of the important varieties of cement products. Compared with the traditional cast-in-place structure, precast concrete members have the advantages of energy saving and low carbon. In the production stage, prefabricated components are standardized in the factory by intensive production mode, which is more beneficial to the control of quality and materials, reduces the loss of materials such as cement, aggregate and various admixtures to a great extent, uses resources more reasonably and efficiently, reduces the generation of waste and reduces carbon emissions. The construction stage is an important stage for prefabricated components to exert their advantages in emission reduction. Because of the assembly construction mode, the construction site not only has no construction waste, but also improves the construction efficiency, shortens the construction period, saves energy consumption and reduces waste generation and carbon emission. In the operation and use stage, prefabricated components have better thermal performance and durability than traditional cast-in-place concrete, which can usually save more than 5% of energy consumption, prolong the service life of buildings, and can be recycled after disassembly, which can effectively save resources and reduce waste generation and carbon emissions.

Taking the precast concrete pile, the most widely used cement product, as an example, through the calculation of its carbon emission in the whole life cycle, it can be found that the carbon emission of precast concrete pile is reduced by 29.6%, the concrete consumption is reduced by 5.9% and the steel bar consumption is reduced by 26% compared with that of cast-in-place pile in the same project. In the process of pipe pile production, the dosage of cement can be reduced by more than 3% by using solid waste powder to modify multifunctional composite admixture, which significantly reduces the carbon emission of products. In the aspect of pollution reduction, the residual slurry of pipe pile is recycled 1% through the residual slurry recycling system; After advanced treatment, the production wastewater can be reused for workshop production, and the reuse rate is 1%; Multi-stage packing wet purification technology solves the problem of gas circulation obstruction and separation of harmful substances through differential contact countercurrent and gas-liquid mixed flow mode, and then thoroughly purifies the harmful substances in the discharged gas through two-stage adsorption filtration mode, thus fundamentally eliminating the discharge of substandard gases.

In recent years, China's cement products industry has gradually changed from traditional extensive production to intensive production. At present, the lean production level in the industry has reached a high level, and a qualitative breakthrough has been achieved in controlling pollutant emissions and effectively utilizing resources. It can be seen that ready-mixed concrete and cement products should not be included in the list of high-emission products.

3. Ready-mixed concrete and cement products industry is a green, low-carbon and environment-friendly industry

With the rapid development of economy and society, the production of industrial solid waste, construction waste and other bulk solid waste in China is increasing, which has become an important factor restricting the further development of economy and society, and has become a fetter for the construction of ecological civilization and green development in China. At present, the cumulative storage of various solid wastes in China is about 6-7 billion tons, and the annual output exceeds 1 billion tons (including 3.3 billion tons of general industrial solid wastes and 1.8 billion tons of construction wastes), and it is increasing year by year. If it is not properly treated and utilized, it will cause serious pollution to the environment, great waste of resources and adverse impact on social ecology.

in recent years, China's concrete and cement products industry has made great progress in the technological innovation of comprehensive utilization of bulk solid waste, and the annual comprehensive utilization of industrial solid waste exceeds 8 million tons, accounting for about 4% of the national comprehensive utilization. Among all material industries, the concrete and cement products industry has become the largest material manufacturing industry using solid waste, which has made important contributions to protecting the environment, saving resources and ensuring the structural safety of engineering buildings. At the same time, by integrating and dredging the upstream and downstream industrial chains, a variety of cement products with high green ecological attributes have been developed and popularized in many engineering fields such as construction, water conservancy, municipal administration and transportation, which has made important contributions to the construction of ecological civilization and green development in China.

Concrete and cement products are not only green, low-carbon and environment-friendly industries, but also important social security industries such as ecological protection and emergency rescue.

IV. Ready-mixed concrete and cement products are indispensable in infrastructure and engineering construction

Concrete and cement products are the most widely used materials and components in infrastructure and engineering construction. They are widely used in housing construction, bridges, airports, highways, railways, various industrial mining and military defense projects, and are indispensable. They are the important support of the brand "Made in China", and they are also the development of prefabricated buildings and green ecological cities.

China's economy has shifted from a high-speed growth stage to a high-quality development stage, and the development of prefabricated buildings has risen to the national strategic level, which will become the trend of future building industrialization. In recent years, with the promotion of national policies, China's prefabricated buildings have been fully promoted and developed rapidly, from housing buildings to various civil engineering buildings. According to the statistics of the Ministry of Housing and Urban-Rural Development, in 22, there were 63 million m2 of newly-built prefabricated buildings nationwide, an increase of 5% compared with 219, accounting for 2.5% of the newly-built construction area. Among them, the newly-started prefabricated concrete structure building is 43 million m2, an increase of 59.3% compared with 219, accounting for 68.3% of the newly-started prefabricated buildings. The prefabricated concrete structure is the mainstream of the development of prefabricated buildings. The vigorous development of green prefabricated buildings requires a large number of precast concrete building components. Similarly, a large number of green concrete products, such as precast concrete box culvert, various water supply and drainage concrete pipes, pavement permeable bricks (slabs), square permeable bricks (slabs) and slope protection ecological bricks (blocks), need to be provided for urban underground utility tunnel, water supply and drainage pipelines, sponge cities and river slope protection construction in China.

At present, the country is still in the period of large-scale construction and continuous improvement of infrastructure, and the position and role of concrete and cement products in the national economic development and construction are unshakable and irreplaceable.

V. Ready-mixed concrete and some cement products are products encouraged by the national industrial policy

1. On October 24, 221, the State Council's notice on printing and distributing the Action Plan of peak carbon dioxide emissions before 23 (Guo Fa [221] No.23) proposed: promoting peak carbon dioxide emissions in the building materials industry. Strengthen the supervision of capacity replacement, speed up the withdrawal of inefficient capacity, prohibit the addition of cement clinker and flat glass capacity, and guide the building materials industry to transform into light, intensive and manufactured products.

2. The Guidance Catalogue for Industrial Structure Adjustment (219 edition) fully closes the main production areas such as the storage area, the main mixing building and the material conveying system, and is equipped with active dust collection and dust reduction equipment, and is operated and managed by an information integrated management system, so as to be an intelligent ready-mixed concrete production line with the ability to absorb urban solid waste; The technical development, production and application of concrete for marine engineering, lightweight high-strength concrete, ultra-high-performance concrete, and cement products such as pavement permeable brick (slab), square permeable brick (slab), decorative brick (block), antique brick, slope protection ecological brick (block) and hydraulic ecological brick (block) are included in the encouraged category.

3. The Catalogue of National Products for Comprehensive Utilization of Industrial Solid Waste Resources issued by the Ministry of Industry and Information Technology in May 218 includes cement products such as pipes (pipe piles), ready-mixed concrete, permeable pavement bricks and slabs, reinforced ceramsite lightweight wallboard and manhole covers.

4. On October 25th, 221, the Ministry of Ecology and Environment issued the Comprehensive List of Environmental Protection (2