Application and advantages of carbonization equipment in sludge carbonization

Working principle of carbonization equipment

In the process of sludge carbonization, carbonization equipment mainly uses pyrolysis technology to heat the sludge in an oxygen-free or anoxic environment. When the sludge is sent to the carbonization equipment, the organic matter in the sludge will undergo a decomposition reaction within a specific temperature range (usually 250-700°C). As the temperature rises, the molecular bonds of the organic matter break and gradually transform into small molecular substances, such as pyrolysis gas (composed of low molecular organic matter, water vapor, etc.), tar, and solid carbonized substances mainly composed of fixed carbon and inorganic substances. For example, in a typical sludge carbonization equipment, the complex organic matter in the sludge is gradually cracked by precisely controlling the heating rate and reaction time to achieve the transformation into different products. This pyrolysis process is essentially different from traditional incineration. Incineration is a violent oxidation reaction under aerobic conditions, which will produce a large amount of greenhouse gases such as carbon dioxide, while the pyrolysis process of the carbonization equipment focuses more on the decomposition and transformation of substances, which can effectively reduce the emission of harmful gases.​

Application scenarios of carbonization equipment in sludge carbonization

Urban sewage treatment plants

The amount of sludge produced by urban sewage treatment plants is large and complex, containing a large amount of organic matter, microorganisms, heavy metals and other pollutants. The application of carbonization equipment in urban sewage treatment plants can effectively treat these sludges. Taking a large urban sewage treatment plant as an example, the amount of dewatered sludge produced daily can reach hundreds of tons. By introducing advanced sludge carbonization equipment, the dewatered sludge is further carbonized. The volume of the sludge after carbonization is greatly reduced, which is convenient for subsequent transportation and disposal. At the same time, the solid carbonized product produced can be used as a soil conditioner for landscaping, providing new resources for urban greening and realizing the resource utilization of sludge. Moreover, during the entire carbonization process, the pollution to the environment is effectively reduced by purifying the tail gas, solving the sludge treatment problem that has long been faced by urban sewage treatment plants. ​

Industrial field

The sludge produced in the industrial production process should not be ignored. Industrial sludge produced by industries such as chemical, printing and dyeing, and papermaking often contains a large amount of toxic and harmful substances. Carbonization equipment plays an important role in the treatment of industrial sludge. For example, in a chemical park, the sludge produced by chemical companies contains high concentrations of organic pollutants and heavy metals. These sludges are carbonized by using carbonization equipment specially designed for industrial sludge. Under the action of high-temperature pyrolysis, organic pollutants are decomposed and transformed, and heavy metals are fixed in solid carbides, reducing their harm to the environment. After carbonization treatment, some of the products can be recycled as industrial raw materials, such as for the production of building materials, etc., which not only reduces the potential threat of industrial sludge to the environment, but also realizes the recycling of resources, bringing a win-win situation of economic and environmental benefits to industrial enterprises. ​

Advantages of carbonization equipment in sludge carbonization

Significant reduction effect

The sludge itself has a high water content and a large volume, which brings great inconvenience to the treatment and transportation. The carbonization equipment evaporates a large amount of water in the sludge through pyrolysis treatment of the sludge, and at the same time, the organic matter decomposes to produce volatile substances such as pyrolysis gas. According to actual data statistics, the volume of sludge can be reduced by 80% - 90% after carbonization treatment. For example, the dewatered sludge, which originally had a water content of up to 80%, was treated by carbonization equipment, and the volume of the solid carbonized product was greatly reduced, which greatly reduced the cost and difficulty of subsequent disposal and achieved efficient sludge reduction. ​

High degree of harmless treatment​

The large number of microorganisms, pathogens, heavy metals and other pollutants contained in the sludge, if not properly handled, can easily cause serious pollution to the soil, water and air. During the operation of the carbonization equipment, the high temperature environment can effectively kill the microorganisms and pathogens in the sludge and achieve harmless treatment. At the same time, for heavy metals, during the pyrolysis process, the heavy metals will undergo a morphological transformation, and some of them will be fixed in the lattice structure of the solid carbide, reducing their mobility and bioavailability in the environment. Relevant studies have shown that after carbonization treatment, the leaching concentration of heavy metals in the sludge is significantly reduced, which effectively reduces the potential harm of heavy metals to the environment and makes the sludge completely harmless. ​

High value of resource utilization​

The solid carbide produced by the carbonization equipment to treat sludge has a wide range of application value. On the one hand, these carbides are rich in fixed carbon, have good adsorption properties and pore structure, and can be applied to the soil as soil conditioners. It can improve the physical structure of the soil, increase the air permeability and water retention of the soil, and provide certain nutrients to the soil, promote plant growth, and improve soil fertility. On the other hand, solid carbides can also be used as raw materials to make building materials, such as adding them to bricks to burn high-strength building bricks to improve the quality and performance of bricks. In addition, the pyrolysis gas generated during the carbonization process can be recycled as energy to provide heat energy for the carbonization equipment itself or other production processes, realizing the recycling of energy and fully tapping the resource potential of sludge. ​

High energy utilization efficiency​

During the operation of the carbonization equipment, attention is paid to the recycling and reuse of energy. While the pyrolysis gas is generated by the pyrolysis of the sludge, the pyrolysis gas is collected and purified by a specific device. The purified pyrolysis gas can be re-transported to the combustion chamber of the carbonization equipment as fuel to provide continuous heat support for the sludge carbonization process. This energy recycling mode greatly improves the energy utilization efficiency of the entire carbonization system. Taking a sludge carbonization project as an example, through the recycling of pyrolysis gas, the energy consumption of carbonization equipment can be reduced by 30% - 40%, effectively reducing dependence on external energy and reducing operating costs, which is also in line with the concept of sustainable development. ​

Environmentally friendly, low risk of secondary pollution​

Compared with traditional sludge treatment methods, the risk of secondary pollution generated by carbonization equipment during sludge carbonization is extremely low. Since the pyrolysis process is carried out in an anaerobic or anoxic environment, a large amount of harmful gases such as dioxins caused by incomplete combustion are avoided. At the same time, the carbonization equipment is equipped with a complete tail gas treatment system to purify the small amount of tail gas generated during the pyrolysis process to ensure that the emission meets the standards. In terms of solid waste, the properties of the products after carbonization treatment are stable, and pollutants such as heavy metals are effectively fixed. It will not cause secondary pollution to the soil and water body like traditional treatment methods, and truly realize environmentally friendly sludge treatment. ​

The application of carbonization equipment in sludge carbonization has brought revolutionary changes to sludge treatment with its unique working principle and significant advantages. Whether in urban sewage treatment plants or industrial fields, it has shown great application potential. With the continuous advancement and improvement of technology, carbonization equipment is expected to become the mainstream technology for sludge treatment in the future, playing a more important role in solving the increasingly severe sludge treatment problem, achieving resource recycling and environmental protection goals.