Against the backdrop of the accelerated implementation of the global “dual carbon” target, the rubber industry, as an important basic industry of the national economy, has become an inevitable trend for its green transformation. Rubber additives, as the core additives in rubber product production, although accounting for less than 5%, determine the key improvement of rubber performance. However, the high-energy consumption synthesis process, dependence on fossil based raw materials, and difficulties in waste disposal involved in its production process have made its carbon footprint a major bottleneck for the sustainable development of the industry.

How to quantify, control, and reduce the carbon emissions of rubber additives throughout their entire life cycle is not only a necessary answer for enterprises to cope with international trade barriers such as the EU Carbon Border Adjustment Mechanism (CBAM) and the US carbon tax, but also a core issue for reshaping industrial competitiveness and promoting global low-carbon rubber industry.

1.Carbon Footprint Accounting: The ‘Green Benchmark’ of the Rubber Additive Industry

Rubber additives, as the core additives in the rubber industry, occupy an important position in the global industrial chain in terms of carbon emissions during their production and application process. Carbon footprint accounting provides a scientific basis for the low-carbon transformation of industries by quantifying greenhouse gas emissions throughout the entire lifecycle, including raw material acquisition, production and manufacturing, transportation and sales, and use and recycling. Taking mainstream rubber additives such as thiazoles, sulfonamides, and amines as examples, their carbon footprint composition has significant industry characteristics:

Raw material process: The production of basic chemical raw materials such as sulfur, aniline, and cyclohexylamine involves high-energy consumption oxidation-reduction reactions, accounting for 30% -40% of the total lifecycle carbon emissions. For example, the production of aniline requires the use of nitrobenzene catalytic hydrogenation process, with an energy consumption of 3000-4000 kilowatt hours per ton of product, accompanied by approximately 2 tons of CO₂ emissions.

Production process: High temperature synthesis reaction (such as sulfurization temperature of sulfonamide additives reaching 150-200 ℃), solvent recovery distillation and other processes are energy intensive, accounting for 40% -50% of the carbon footprint. According to data from a production line with an annual output of 10000 tons of accelerator M, the heating and vacuum distillation system of the reaction kettle consumes over 5000 tons of standard coal per year, corresponding to a carbon emission of approximately 13000 tons of CO₂.

Cycle stage: The carbon conversion pathway of residual additives in waste rubber products is not yet clear. Currently, only 10% -15% of carbon elements are recovered through thermal cracking, while the rest are emitted in the form of landfill or incineration.

The current internationally recognized ISO 14067 product carbon footprint standard has become a rigid threshold for multinational rubber companies to enter the supply chain. Giants such as Michelin and Bridgestone require additive suppliers to submit carbon footprint reports, and companies with excessive carbon emissions face the risk of order reduction. Domestic enterprises such as Yanggu Huatai and Tongcheng New Materials have initiated the construction of carbon footprint management systems, and have achieved full chain data monitoring from raw material procurement to product delivery by introducing life cycle assessment (LCA) software.

2.Technological innovation: the “core engine” of low-carbon rubber additives

(1)Breakthrough in Green Synthesis Technology

Catalytic technology upgrade

The direct oxidation method with hydrogen peroxide replaces the traditional nitric acid oxidation process for the production of sulfonamide additives, which can reduce nitrogen oxide emissions by more than 70%. A certain enterprise adopts a supported palladium catalyst to increase the selectivity of cyclohexylamine oxidation reaction to 92%, reduce by-products by 40%, and reduce carbon emissions per unit product by 28%.

Electrochemical synthesis technology is applied in the production of thiazole based additives, achieving direct coupling between aniline and carbon disulfide through a diaphragm free electrolytic cell, avoiding the emission of hydrogen sulfide waste gas in traditional processes, and improving carbon efficiency by 15% -20%.

Substitution of bio based raw materials

Replacing petroleum based thiols with natural rubber sulfides reduces the carbon footprint of bio based thiol accelerators by 45% compared to traditional products. The BioAccelerator series developed by AkzoNobel in the Netherlands uses microbial fermentation to produce thioamides, with the raw material carbon source coming from sugarcane bagasse biomass.

Replacing some carbon black with lignin based reinforcing agents can reduce 30% of fossil carbon dependence in the production process of rubber products. A certain enterprise in Shandong uses lignosulfonate extracted from papermaking black liquor for rubber formulation, reducing carbon emissions by 0.8 tons of CO ₂ per ton of product.

(2)Energy saving equipment iteration

Integrated Reaction Heat System

By using multi effect evaporation and heat pump technology to recover the waste heat from synthesis reactions, a certain accelerator CBS production line has reduced steam consumption from 8 tons/ton of product to 3 tons/ton of product, saving over 4000 tons of standard coal annually and reducing carbon emissions by 11000 tons of CO₂.

Microchannel reactors are applied in low-temperature synthesis processes, reducing the reaction temperature from 120 ℃ to 60 ℃, reducing energy consumption by 50%, and improving product selectivity to over 95%.

Intelligence control system

The energy management system (EMS) based on the Internet of Things (IoT) monitors the energy consumption of production equipment in real time. A certain antioxidant RD production line has optimized the mixing rate and temperature control curve, resulting in an 18% reduction in unit product electricity consumption and an annual carbon reduction of over 600 tons of CO₂.

The photovoltaic power generation and energy storage system are connected to the auxiliary production park. A 5MW distributed photovoltaic power station has been built at a certain base in Yanggu Huatai, with an annual power generation of 6 million kWh, covering 30% of the production electricity demand and reducing carbon emissions by about 3600 tons annually.

3.Future Trends: Roadmap for Carbon Neutrality of Rubber Additives

(1)Technological Evolution Direction

Atomic economy synthesis: The photocatalytic oxidation method increases the atomic utilization rate from 65% to 90%, and the biosynthesis technology reduces carbon footprint by more than 70% through gene editing of microorganisms.

Carbon Capture and Utilization (CCU): Chemical absorption method captures CO ₂ for the production of fillers, with a cost of approximately 300 yuan/ton; Microbial carbon fixation technology achieves “carbon sulfur synergistic recovery” and converts waste rubber sulfides.

(2)Industrial ecological reconstruction

Service oriented transformation: Yanggu Huatai launches carbon management aaS platform, providing digital tools for small and medium-sized enterprises; The “shared factory” model integrates production capacity, reduces unit carbon emissions by 22%, and increases equipment utilization by 35%.

International standard leadership: China takes the lead in developing the ISO “Guidelines for Carbon Footprint Accounting of Rubber Additives”, expected to be completed by 2025; The “the Belt and Road” exports low-carbon technologies, such as the Thai bio based mercaptan project to reduce carbon by 30%.

The carbon footprint management of rubber additives is a comprehensive innovation of technology, system, and ecology. Faced with challenges such as EU carbon tariffs and US carbon taxes, Chinese companies need to take green synthesis processes, intelligent equipment upgrades, and regional cluster collaboration as the starting points to build a carbon management system that complies with international rules. At the same time, innovative directions such as bio based additives and carbon capture technology are driving the industry from “cost competition” to “carbon competitiveness” competition. When carbon footprint becomes the core indicator of industrial value, enterprises that are the first to complete low-carbon transformation will take the strategic initiative in the global rubber industry’s greening process. This is not only an inevitable choice to respond to international rules, but also an important opportunity for the upgrading of China’s rubber industry.

Article source: www.xianjichina.com

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