【Ten Years of Rapid Development in Chemical Engineering Equipment】The world’s first low-temperature SCR denitration system for sintering flue gas at 180°C was successfully put into operation from 1731 to 2018

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Happy May Day 2024! Safety first. Let’s give praise and support to the achievements made in China’s chemical engineering technology and equipment. **********************【Ten Years of Progress in Chemical Engineering Equipment】A continuously updated summary post is available; feel free to join the discussions at https://bbs.hcbbs.com/thread-3576046-1-1.html (Source: Haichuan Chemical Engineering Forum) ***************** On November 2, 2018, the 180°C low-temperature SCR denitration projects for the flue gases from Tangshan Ruifeng Steel (Group) Co., Ltd.’s No. 1 and No. 3 sintering plants were successfully put into operation. This project is the world’s first low-temperature SCR denitration system for sintering flue gas. It was EPC-general contracted by Tongxing Environmental Protection Technology Co., Ltd., and on October 24, flue gas was introduced for the first time in the heat-load linked trial operation, with successful commissioning after just one attempt. According to the control panel display and historical data, a total of 2 layers of catalysts are installed in the denitration reactor. The temperature of the first catalyst bed is 184.9°C, while that of the second catalyst bed is 178.2°C. The inlet NOx level in the denitration reactor is typically between 200–300 mg/Nm3, with the outlet NOx level remaining below 20 mg/Nm3. By adjusting the ammonia injection rate, the outlet NOx level can be kept below 5 mg/Nm3, with ammonia escape at ≤1 ppm. The emission concentration is far lower than the 50 mg/Nm3 threshold specified by ** and the local standards of Hebei Province. This demonstrates the suitability and feasibility of the low-temperature SCR denitration process for sintering flue gas, enabling ultra-low emissions of NOx from such flue gas – or even near-zero emissions in the future. Based on data analysis from since its operation, Tongxing Environmental Protection’s use of low-temperature denitration at 180°C offers a significant advantage in terms of reducing gas consumption. Through on-site temperature adjustment, the catalyst carries out denitrification at different temperatures; the gas consumption is as follows: (flue gas volume is approximately 700,000–840,000 Nm3/h). 1. At the GGH raw flue gas outlet, the temperature is raised from 155°C to 180°C (denitrification temperature), with a gas consumption of 7,835 Nm3/h ； 2. The temperature at the outlet of the GGH for the raw flue gas increased from 220°C to 250°C (the denitration temperature); the gas consumption was 15,778 Nm3/h ； Note: The GGH is designed and selected based on a low-temperature catalyst decomposition temperature of 250°C. Based on the market price of blast furnace gas at 0.1 yuan per cubic meter, the use of a denitration catalyst at a reaction temperature of 180°C results in annual cost savings of around 6.958 million yuan compared to using such a catalyst at 250°C, which clearly demonstrates the significant energy-saving benefits of low-temperature SCR denitration for sintering flue gases. According to the on-site managers of Ruifeng Steel Group and relevant experts, the low-temperature SCR denitration project for the flue gas from Sintering Lines 1# and 3# boasts the following outstanding advantages: 1. Currently, this is the world’s first successful application of true low-temperature SCR technology for purifying flue gas from sintering machines, with a denitration efficiency of over 95% at an operating temperature of 180°C. 2. By using a low-temperature denitration process, the volume of flue gas under identical standard conditions that enters the SCR denitration reactor is relatively small; this results in a lower system temperature, with the minimum temperature drop being able to be kept within 2°C. This helps to reduce coal consumption and lower operating costs to some extent. 3. The use of low-temperature SCR denitration reduces the flue gas flow rate under the operating conditions of the GGH heat exchanger, thereby decreasing the diameter of the GGH and significantly lowering its initial investment cost.