Have you paid attention to steam quality?

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This post was last edited by goldliyang on 2017-3-23 09:18. For Steam users, the quality of Steam is of paramount importance; it affects the stability, reliability, and cost-effectiveness of system operation, as well as the quality of products, production efficiency, and energy consumption. Unfortunately, most steam users have not paid enough attention to this, which has led to a series of problems in the steam system. The four key indicators of steam (saturated steam) quality are cleanliness, dryness, purity, and stability of pressure/temperature. 1) Cleanliness: Steam pipes may contain rust and carbonate deposits, as well as welding slag and fragments of sealing materials left over from installation. These impurities can cause blockages and damage to valves and equipment, and they also accelerate the wear of the pipes. 2) Dryness: Improper water treatment for boiler make-up water, unreasonable control of boiler water level, and high peak loads over short periods of time can all cause foaming in the boiler, resulting in boiler water being carried out with the steam at the boiler outlet. As steam flows through the pipes, the heat loss from the pipes causes some of the steam to condense, increasing the amount of condensate water in the pipes. The chemicals and other impurities present in the condensate water deposit on the surfaces of heat exchange equipment, reducing its efficiency. Moreover, these deposited impurities form scales on the metal surfaces of the equipment, leading to uneven heating of those surfaces and a shortened lifespan for the equipment. Furthermore, the presence of water vapor reduces the evaporation enthalpy of the vapor, increasing the vapor consumption ； The moisture in the steam increases the thickness of the water film on the heat exchange surface, creating an additional thermal resistance to heat transfer. 3) Purity: Air is present in steam systems, as the steam generated by boilers inevitably contains a small amount of air. In addition, air enters during the startup of pipes and equipment, and it is drawn in due to the internal vacuum when the systems and equipment are shut down. Air has a very low thermal conductivity, making it a poor conductor for heating. In terms of thermal conductivity, 1 millimeter of air layer is equivalent to 15.6 meters of copper wall. Air in the steam system reduces the production capacity of steam-using equipment, and it also accelerates the corrosion of pipes, valves, and equipment. 4) Stability of pressure/temperature: To meet the heating requirements of the process, the steam pressure at the boiling point must reach the required value. At the same time, the steam pressure should not be too high, otherwise it will increase steam consumption. High-pressure steam for supply, low-pressure steam for use. Provide steam-using equipment with the minimum and stable pressure required. This way, it meets the production needs while also achieving energy savings and reduced consumption. By selecting the appropriate steam delivery pressure and pipe diameter, ensuring effective insulation of the pipes and valves, implementing proper pipe drainage and venting, and adding pressure reduction and stabilization at the point of use, it is possible to maintain stable pressure/temperature at the steam consumption points.