TRT Corrosion and Scale Inhibitor Introduction

TRT corrosion and scale inhibitor introduction

TRT is an energy recovery device that uses the residual pressure at the top of the blast furnace, introduces blast furnace gas into the expander to generate power to drive the generator for power generation.

After dust removal, most of the dust in the blast furnace gas is removed, but certain amount of floating dust, steam, oil mist, and a variety of acidic gases (such as: H2S, HCL, CO2, etc.) produced the impure blast furnace raw materials still remain in the gaseous medium. At the same time, due to the existence of scouring and corrosion, some corrosion products in the gas pipeline will also be mixed in the coal gas, and the final entering the TRT device is a multiphase flow of gas-gas-solid. After the blast furnace gas the TRT device, the temperature will gradually decrease due to expansion and work. The acid gas in the coal gas will dissolve in the condensate water and form an acidic water film the surface of the blade, which will corrode the surface of the blade. The surface roughness of the corroded metal surface is greatly reduced. At this time, some corrosion, oil pollutants, dust, etc. adhere to the blade. At the same time, due to the decrease of the temperature, flow rate and pressure of the coal gas, trace components in the coal gas, such as (NH4   , Cl-, etc.) will precipitate in the form of crystallization, forming various inorganic salts. inorganic crystal can adhere to the metal surface to form scale. The small particles of floating dust, salt crystals, etc. in the coal gas will be charged by themselves, and interaction will form larger charged impurity particles. These charged fine particles will eventually adhere to the moving blade, static blade and inlet and outlet flue of the device, forming a layered scaling. Due to the uneven scaling, the dynamic balance of the device is destroyed, resulting in a decrease in TRT power generation, an increase in the vibration value of the main shaft and an automatic adjustment to stop, and a short inspection cycle of the device (less than 2 months).

For the TRT blast furnace gas residual pressure power generation device the TRT corrosion inhibitor developed by our company can achieve good treatment effect by adding it.

The principle and characteristics of the corrosion inhibitor:

1. After the agent sprayed into the blast furnace gas, it is instantly gasified and evenly mixed with the help of the temperature and momentum of the blast furnace gas.

2. The agent and inorganic salt crystal in the coal gas have a eutectic or adsorption on the surface of the crystal, distort the lattice, and destroy the crystallization behavior and of the inorganic salt; change the shape and size of the crystal, avoid the interconnection between the crystals to form a three-dimensional network structure, and prevent the further formation development of the crystal, and prevent the salt crystal (scale) in the coal gas from depositing on the blades and rotors of the turbine.

3. The surface- component in the agent can clean the surface of the blade, eliminate the charge on the metal surface, and prevent impurities from adhering to the blade.

4. The agent a layer of corrosion inhibitor film on the surface of the blade, which is metal-friendly at one end and water-repellent at the other end, preventing salt components and gases from contacting the surface of the blade and keeping the surface of the metal on the blade and other parts of the device smooth.

5. The agent absorbs the acid gas the coal gas, reduces the concentration of the acid gas, and achieves the effect of corrosion resistance to prevent pitting corrosion.

Estimation of agent dosage

The agent is fed, and the amount of agent added is determined according to the scaling condition of the TRT device and the temperature, humidity and dust content of the coal gas, and the agent concentration usually 90-150g/104m3.h

Taking 250,000 Nm3/h blast furnace as example

The amount of agent added per hour is 2.25-3.75KG, one day is 67.5-90KG, and one is 2.025-2.7T.