In the refining and chemical industry, natural gas purification, coal chemical industry, and other industries, a large amount of tail gas will be generated during the production process of sulfur recovery. These exhaust gases are mainly nitrogen, and also contain a small number of flammable components such as hydrogen sulfide, hydrogen, and sulfur. In the process of tail gas incineration, new pollutants nitrogen oxides will be produced.
In order to suppress the generation of NOx, the conventional technologies of grading air distribution, oxygen-deficient combustion, and flue gas circulation are used, but they are not ideal or have drawbacks. In order to meet the requirements of environmental protection and ultra-low emission, Ruichang invented the exhaust gas ultra-low NOx emission technology.
Details of Ultra-low NOx Emission Technology
The ultra-low NOx emission technology of exhaust gas is based on the staged air distribution and ultra-short flame technology, and the method of exhaust gas splitting is added to achieve ultra-low nitrogen emission. The amount of NOx in this technology can be stably controlled below 30mg/Nm³. The core of this technology is that the internal structure of the burner has been optimized, and at the same time, the conventional furnace front control system has been adaptively improved, that is, “structure improvement + feedforward automatic control loop“.
The ultra-low NOx emission technology was founded in 2018 and has applied for a variety of patent structures. Currently, there are 6 structures. After nearly 3 years of research experiments and technical iterations, it has begun to be widely promoted and applied.
Comparison of effect data before and after modification of sulfur recovery unit
Test data before transformation:
Flue gas emission index: oxygen content 5%; CO emission value 2000mg/Nm³; NOx emission value 50mg/Nm³.
Test data after transformation:
Flue gas emission index: oxygen content 4.5%; CO emission value ≤300mg/Nm³; NOx emission value ≤20mg/Nm³.
Technical Advantages
- This technology can ensure both ultra-low emissions of NOx and CO and solves the drawbacks of other NOx reduction technologies that only rely on reducing furnace temperature and sacrificing CO emissions to ensure NOx compliance.
- Compared with the flue gas recirculation technology, this technology does not require additional induced draft fans, requires less investment, simple layout, and strong operability.
- Compared with the technology of steam spray or water spray to reduce NOx, no additional heating of other media is required, no additional public utility consumption, energy-saving, and environmental protection.
- The ultra-low NOx emission technology has a wide range of adaptability, a large adjustment range of primary exhaust gas volume and primary air volume can adapt to a variety of working conditions, and can be used in other low calorific value waste gas incineration and nitrogen reduction processes in non-sulfur industries.
