Purging of steam and air pipes

The purge flow rate is required to be the same as that during normal operation; what remains are the degree of pressure reduction and the purge time. There is also the issue of steam preheating. I haven’t calculated it; at most, it’s just a usage statistic.

Ensure the pressure for purging; as long as the pressure is sufficient, a thorough cleaning will be achieved

I’d like to mention it specifically. Piping purging should be carried out in sections; if the piping is fully installed before purging, it is of little use, as the pressure drop is significant and the goal of cleaning the pipes is not achieved

Steam pipes cannot be purged in segments; they must be purged all at once. The high flow rate of steam ensures thorough cleaning

Blowing is done until the pipe is clean; the dirtier the pipe, the lower the flow rate, the longer the time required, and the greater the amount of gas used

I’ve encountered situations where slag from welding wasn’t properly cleaned out of the steam pipes, remaining stuck inside them and preventing the solenoid valves from closing properly. I’ve also seen cases where metal powder accumulated in the compressed air pipes, causing the valves to fail to close quickly. All these issues arose because the purging process wasn’t carried out in accordance with the established procedures

It’s fine to blow air in segments, but the key question is how to blow steam in segments Steam can only come out of the boiler

I haven’t calculated it. As long as it does not affect the production equipment, purge until satisfactory.

1. The driving force for pipeline purging is flow velocity; only a sufficient flow velocity can carry away the impurities inside the pipes. 2. To maintain a flow velocity at a reasonable level, there are differences between using air and steam: 2.1. Air is in gaseous state at normal temperatures, and aside from the influence of pressure drop in the pipes, its flow velocity can be considered constant during purging. 2.2. Steam is in gaseous state above its saturation point, while it is in liquid state at normal temperatures. During the steam purging process, the steam entering the system is in gaseous state. When the flow rate of the purging steam is insufficient, heat loss from the pipes will rapidly reduce the enthalpy of the steam; the superheated steam gradually turns into saturated steam and even water, at which point there is no longer any meaningful flow velocity. 2.3. Ensuring an adequate steam flow rate and proper pipeline insulation are necessary conditions to achieve effective steam purging

I’d like to ask: after the material transfer pump is stopped, the flow rate is 20 m3/h. The pipes used are Yage female connectors, DN80 in size, with a length of approximately 40 meters. Compressed air at 3 barg is used; how does one calculate the amount of compressed air required, in terms of x m3/h?