NANJING TECH UNIVERSITY

Numerical simulation of NOx reduction using low-oxygen combustion and optimization in a TTF precalciner

This paper describes the use of low-oxygen combustion technology to reduce NOx emissions in cement production. Numerical simulation was also employed to simulate the pulverized coal combustion, calcium carbonate decomposition and NOx reduction process in the precalciner of a 5000 t/d clinker cement production line. The simulation gave a temperature at the precalciner outlet of 1260 K, a CO2 mass fraction of 28%, an O2 concentration of 1.2% and an NOx concentration of 523 ppm. The data were in good agreement with the actual measurements. The low-oxygen combustion technology was also optimized by changing the oxygen content in the kiln exhaust gas in order to achieve the best conditions. The results showed that the NOx concentration at the outlet of the precalciner would be lowest (468 ppm) when the oxygen content in the kiln exhaust gas was 3%.

1 Introduction

The cement industry is the third largest source of nitrogen oxides after the power industry and motor vehicles, and China‘s cement production accounts for 65% of global cement production. The problem of the resultant pollutant emissions is also a concern for society. The greatest possible reduction of NOx emissions while at the same time ensuring the economic benefits of cement plants has therefore become a major issue. Many scholars at home and abroad have carried out a great deal of research into this problem. Zhao [1] studied the influence of different amounts and locations...

Related articles:

Issue 7-8/2018 WUHAN UNIVERSITY OF TECHNOLOGY

Gas formation characteristics and inter-action during pulverized coal combustion in a precalciner environment

Schematic diagram of the experimental system

1 Introduction China’s total energy consumption in 2014 was equal to 4.26 billion t of standard coal. Coal consumption accounts for more than 66?% of the total energy consumption in China, which...

more
Issue 1-2/2019 WUHAN UNIVERSITY OF TECHNOLOGY

Coal combustion mechanisms and fuel NOx formation characteristics in a precalciner environment

1 Introduction Nitrogen oxides constitute one of the main air pollutants and the NOx emission regulations for the cement industry are becoming more and more stringent. Precalciners are used in the...

more
Issue 3/2022 WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Formation characteristics of self-generated nitrogen oxides in a cement precalciner

1 Introduction NOx is one of the main components of air pollution, and coal combustion is the main source of nitrogen oxides. Countries and local governments have formulated more and more stringent...

more
Issue 6/2021 WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Effect of precalciner collaborative disposal of RDF and bituminous coal on the generation and transformation of NOx and SO2

1 Introduction The increasing production of cement has led to a significant increase in coal consumption. Under the typical pulverized coal combustion state, NOx is mainly generated by nitrogen...

more
Issue 3/2022 WUHAN UNIVERSITY OF TECHNOLOGY | ANSHAN JIDONG CEMENT CO. LTD

Numerical simulation of oxygen-enriched combustion in a rotary kiln in the primary air and the secondary air respectively

1 Introduction China is a major cement producer and consumer. According to statistics, China produced 2.4 billion?t of cement in 2020 [1]. The cement industry is also the main coal consumption and CO2...

more