Integrated Continuous Sludge Drying & Carbonization Technology

Dingjiu Environment places great emphasis on the performance of its technology in practical applications. We ensure that projects achieve the desired results through rigorous engineering design, precision equipment manufacturing, comprehensive automation control systems, and standardized operation and management processes. After each project is put into operation, continuous performance monitoring and data collection are carried out, including key indicators such as tail gas emissions (dust, SO₂, NOx, dioxins, etc.), biochar quality (fixed carbon, heavy metal content, etc.), and energy consumption. We have multiple successfully commercialized project cases, such as the Changsha Economic Development Zone sludge carbonization project and the Guangzhou Zengcheng sludge carbonization project. The long-term operation data from these projects fully demonstrate that our technology meets design requirements and achieves industry-leading levels in terms of environmental emission standards (for example, dioxin emissions in tail gas are far below EU standards, and heavy metals are effectively immobilized), reduction efficiency, resource output, and system stability. Relevant test reports and operation data can be provided for review depending on specific cooperation discussions. We firmly believe that transparent data and successful cases are the best proof of technical strength.

The economic efficiency of the project is a key focus of Dingjiu Technology. In addition to the direct economic benefits from biochar and energy recovery, we reduce operating costs and enhance investment returns through various optimizations: First, the high degree of automation and intelligence in the system significantly reduces the need for on-site operation and maintenance personnel, lowering labor costs. Second, strong energy self-sufficiency, by efficiently utilizing self-generated pyrolysis gas, greatly reduces dependence on external fossil fuels or electricity, effectively controlling energy costs. Third, high equipment integration and relatively compact footprint reduce land use costs and civil construction investment. Fourth, key components such as oil and gas pipelines are maintenance-free through tar cracking technology, reducing downtime for maintenance and related costs. Fifth, the treatment process is completely harmless, avoiding potential environmental fines or secondary treatment costs from traditional disposal methods. Sixth, biochar products, as carbon sink products, have potential additional revenue in the future carbon trading market. In summary, Dingjiu Technology strives to provide investors with competitive economic returns through full lifecycle cost optimization and value creation.

In response to the challenges of varying characteristics of organic solid waste, Dingjiu's oxygen-free carbonization system has been thoroughly considered in both design and operation. Firstly, the integrated equipment incorporates an efficient continuous drying section capable of handling municipal sludge with moisture content up to 80%. By precisely controlling the drying temperature and residence time, it ensures that the moisture content of the material entering the carbonization section remains within a suitable range. For materials with large fluctuations in calorific value, such as domestic waste, the system is equipped with advanced online monitoring and intelligent control systems that can analyze feed characteristics in real-time (e.g., indirectly sensing calorific value changes) and automatically adjust key process parameters such as carbonization temperature, gas supply volume, and air ratio (in the combustion furnace section) to maintain stable carbonization processes and optimal pyrolysis efficiency. Furthermore, the equipment is made of special alloys resistant to high temperatures and corrosion, with key components (such as inlet/outlet seals and screw conveyors) reinforced in design, ensuring long-term reliable operation under complex conditions. When co-processing multiple solid wastes, a reasonable blending scheme can also be implemented to utilize the complementary characteristics of different materials, further enhancing overall treatment effectiveness and energy efficiency.

Dingjiu's oxygen-free carbonization technology is committed to achieving 'complete resource recovery' of organic solid waste, rather than just reduction and harmlessness. This is specifically reflected in the multi-valued utilization of products: First, the biochar produced is a high-quality soil amendment and carbon-based fertilizer carrier, which can significantly improve soil structure, enhance fertility, immobilize heavy metals, and increase carbon sinks. It has been verified in agriculture, landscaping, and ecological restoration fields; at the same time, it can also serve as an additive for environmentally friendly building materials (such as permeable bricks and lightweight wall panels), or be further processed into high-value-added products like activated carbon and conductive materials. Second, the high-calorific-value pyrolysis gas generated, after meeting the system's own energy needs, can be used for electricity generation, heating, or as synthesis gas for chemical production, achieving cascade utilization and efficient recovery of energy, significantly reducing the overall energy consumption and operating costs of the project. For complex materials like mixed municipal solid waste, the inorganic residues after carbonization (such as metals, glass, ceramics, etc.) are also easier to sort and recover. This comprehensive resource recovery path truly transforms the original 'waste' into marketable 'products,' constituting a key closed loop of the circular economy.

Dingjiu Technology does not merely rely on inert gas protection to construct and maintain an "oxygen-free" carbonization environment; instead, it innovatively utilizes resources generated within the system itself. The core lies in the large amount of water vapor produced in the drying section, which, through clever equipment structure design, forms a dense "water vapor barrier" that effectively blocks the infiltration of external air into the carbonization section. Meanwhile, the entire system operates under a slightly negative pressure state, further preventing oxygen intrusion. This "self-produced and self-consumed" oxygen-free assurance mechanism not only reduces dependence on external inert gases and lowers operational costs, but more importantly, it provides extreme anaerobic conditions for the pyrolysis carbonization reaction. Under these conditions, organic matter primarily undergoes cracking and polycondensation reactions, with carbon elements more readily converted into solid biochar and combustible gases rather than undergoing oxidative combustion to form CO₂. The improvement in the quality of the final products is reflected in the following aspects: the biochar has a higher fixed carbon content, a more developed pore structure, and better stability; the pyrolysis gas has a higher calorific value and purer composition. The impact on the environment is demonstrated as follows: the generation of highly toxic by-products such as dioxins and furans is reduced to trace levels or even below detection limits, far lower than the strictest emission standards; heavy metals are more easily passivated in a reducing atmosphere and stably fixed within the lattice structure of the biochar, significantly reducing their environmental mobility risk and bioavailability.

The core of Dingjiu Environment's organic solid waste oxygen-free carbonization technology lies in the deep thermochemical conversion of municipal sludge and various organic solid wastes (such as household waste, kitchen waste, agricultural and forestry residues, etc.) through an integrated continuous drying and carbonization equipment, under a strictly controlled oxygen-free (extremely low oxygen content, usually zero) high-temperature environment. Compared with traditional or partial pyrolysis technologies, the essential differences and innovations of this technology are reflected in the following aspects: Firstly, through a unique "steam seal" and precise negative pressure control, a truly "oxygen-free" environment is achieved, which suppresses the formation of harmful substances such as dioxins from the source and maximizes the retention of energy and carbon value in the products (biochar and pyrolysis gas). Secondly, our original "multi-stage heterogeneous catalytic cracking technology" is a breakthrough solution to the common tar problem in pyrolysis processes. It can efficiently crack complex tar macromolecules into clean small-molecule combustible gas, which not only improves the quality and utilization efficiency of pyrolysis gas, but also achieves long-term maintenance-free operation of the oil and gas pipelines, significantly enhancing system stability and economy. Finally, the entire system is highly integrated and automated, capable of continuous and stable operation, and adaptable to complex feedstocks with fluctuating moisture content, ensuring consistent and efficient treatment results.