Carbon black is an amorphous form of carbon produced through the incomplete combustion and pyrolysis of by-products from coal chemical processes, such as coal tar and anthracene oil, at high temperatures. Carbon black tail gas refers to the gas that remains after carbon black particles have been separated from the flue gas during production. The composition of this tail gas includes oxygen, methane, nitrogen, carbon dioxide, carbon monoxide, water vapor, and hydrogen.
For every ton of carbon black produced, approximately 8,000 to 13,000 cubic meters of tail gas can be generated. With a calorific value of around 700 kcal per cubic meter, this gas contains a significant amount of energy. However, most carbon black plants discharge the tail gas directly into the atmosphere, resulting in substantial energy waste and environmental pollution—neither economical nor environmentally friendly.
The combustible gases in carbon black tail gas can be utilized for power generation using internal combustion engines or boilers.
1. Power Generation Using Carbon Black Tail Gas with Internal Combustion Engines
This method involves using carbon black tail gas as fuel to drive internal combustion engines, which in turn power generators to produce electricity.
This approach effectively recovers the combustible components in the tail gas (such as carbon monoxide), enabling energy reuse. It not only reduces harmful emissions but also generates electricity, contributing to economic benefits. However, due to the complex composition of carbon black tail gas, pretreatment is necessary to meet engine requirements—such as removing impurities and adjusting temperature and pressure. Additionally, it is crucial to use appropriately selected engines that are resistant to wear and corrosion to ensure stable and reliable operation.
（1）Energy Reuse and Cost Advantages Discharging tail gas directly results in energy loss and pollution. Utilizing it as engine fuel for power generation enables secondary energy utilization, reducing electricity costs for carbon black producers. For example, Yongdong Co., Ltd. achieves self-sufficiency in electricity for production and office use through tail gas power generation.
（2）Environmental Benefits Carbon black tail gas contains combustible gases like carbon monoxide, which can cause air pollution if released untreated. Power generation from tail gas reduces the emission of harmful gases, mitigates environmental impact, and supports corporate goals of energy conservation and emission reduction in compliance with environmental regulations.
（3）Stable and Reliable Power Output The internal combustion engine system for tail gas power generation is relatively simple and stable in operation. The output power can be adjusted based on actual demand, making it suitable for fluctuating power loads within the facility and ensuring a reliable electricity supply.
（4）High Fuel Flexibility Internal combustion engines used in this application can adapt to variations in tail gas composition and calorific value to a certain extent, without the need for significant equipment modifications. This reduces capital and operating costs for enterprises.
2. Power Generation Using Carbon Black Tail Gas with Boilers
This method uses carbon black tail gas as fuel in boilers to produce steam, which then drives a steam turbine to generate electricity.
This system offers multiple advantages. From an energy utilization perspective, it converts waste gases that would otherwise be vented into a valuable energy resource, improving overall energy efficiency. From an environmental standpoint, it reduces atmospheric pollution caused by direct discharge of tail gases and helps enterprises meet environmental standards.
Before combustion, the tail gas must be pretreated—removing dust, tar, and other impurities, and adjusting parameters such as temperature, pressure, and calorific value to ensure stable and efficient combustion in the boiler. The system should also be equipped with comprehensive monitoring and control systems to oversee combustion conditions, steam parameters, and other operational data in real time. This ensures safe, reliable, and smooth power generation, bringing both economic and environmental benefits to the enterprise.
