Optimization and transformation of shaft end seal

The shaft end sealing form of TRT Unit 1 (see Figure 1 below) is labeling seal (comb seal) + carbon ring seal + N2 seal combined shaft seal technology, that is, labeling gas seal is used inside (inner side) and carbon ring seal is used outside (outer side). The sealed nitrogen is blocked from the nitrogen inlet at a pressure greater than 0.02-0.03mpa of the sealed gas. The sealing effect is poor and the gas leakage is serious. The gas concentration in the machine room seriously exceeds the standard. The main reasons are as follows: ① due to the small number of equivalent teeth and relatively few times of throttling expansion, the leakage is serious; ② When the unit passes the critical speed or abnormal vibration occurs, the amplitude is large, and there will be contact between the teeth on the rotor and the sealing sleeve. Due to the thin sealing teeth caused by pulling apart, when friction occurs, it will be quickly worn and the sealing gap will increase, resulting in gas leakage.

There is an annular chamber between the "J" teeth of the labeling seal. When the unit is running, there is strong rotating air flow in the chamber, and the running track of the rotor is oval, so there is a great difference in the tangential force of the strong rotating air flow around the rotor circumference, which is very easy to cause air flow excitation and unit vibration.

In order to improve the problems of shaft end seal, after research and discussion with Shaangu, it is decided to adopt a new type of shaft end seal on No. 1 TRT turbine. The new type of TRT shaft end seal is honeycomb seal + carbon ring seal + N2 seal, as shown in Figure 2. After the installation of the new seal in April 2016, the gas leakage was greatly reduced, and the gas concentration was less than 24 × 10 - 6, there was no gas concentration exceeding the standard in the machine room due to shaft end seal leakage, the unit operated safely and stably, and the power generation efficiency was improved. In addition, the new sealing components are easy to install and replace spare parts.

Optimization of top pressure regulation control program

When the blast furnace production is abnormal, the top pressure and flow fluctuate greatly, which will impact the automatic TRT, resulting in that the thrust pad conversion method is a reliable dynamic analysis method.