Is it permissible to perform hot work on the heat exchange coal gas pipeline?

After replacing with steam, it is isolated from the converter using a blind flange. The converter is filled with nitrogen to maintain a slight positive pressure, and then work can be carried out on it. (Remember to conduct a fire hazard analysis.)

Isolate the converter from the system; after replacing it with steam or high-purity inert gas and confirming that the environment is suitable, then proceed with welding work. Be careful that no convection occurs in the pipelines connected to the converter to prevent air from entering. As a precaution, an inert gas can be continuously introduced into the furnace to maintain positive pressure. After completing the task, quickly replace it with gas.

Follow the standard procedures for working with open flames. Select the smallest possible system that is still safe to use, isolate it from other systems using blind flanges, purge it with inert gases such as nitrogen, and maintain a slight positive pressure. Also, be sure to conduct the necessary analyses before starting work. If the pipeline is included in the hot work design, remember to conduct a pressure test for airtightness before putting it into use.

What you mean is welding under pressure without displacement. Safety precautions for hot work under pressure without displacement 1. Hot work under pressure without displacement is not permitted in the following situations: unstable production. The equipment, pipes, etc. are severely corroded. 2. A construction safety plan must be developed, and safety and fire prevention measures must be implemented. During hot work, the workshop supervisor, the safety officers from the unit performing the hot work as well as those from the unit affected by it, the personnel from the factory’s safety and fire prevention department, and the factory manager or chief engineer must be present on site. If necessary, a professional fire brigade can be called in to oversee the operation. 3. It is necessary to ensure that the oxygen content in the hot work atmosphere is ≤0.5%. 4. Before carrying out hot work, the production unit must inform the factory’s production scheduling department and relevant units, so that appropriate emergency measures can be taken promptly in case of any abnormalities. 5. During hot work, a dedicated person must be assigned to monitor pressure changes within the production system, ensuring that the system maintains a positive pressure of at least 980.665 Pa (100 mm water column). Work involving open flames should be stopped when the pressure is below 980.665 Pa (100 mm water column). The cause must be identified and measures taken before work can resume; working with open flames under negative pressure is strictly prohibited. Good ventilation at the site where hot work is carried out is necessary to ensure that any leaked gases can be removed smoothly.