Which factors influence steam quality?

Steam quality is significantly influenced by pressure, temperature, and water impurities. The relationship between pressure and temperature is crucial because steam quality can vary according to the saturation temperature at a given pressure. Higher pressures result in higher saturation temperatures, meaning the water must reach a higher temperature to produce steam and maintain quality.

Temperature is directly linked to the phase change from water to steam; if steam is produced at temperatures that are too low, it may contain a higher percentage of water droplets, thereby decreasing its quality.

Water impurities also play a key role in steam quality. Presence of dissolved solids, minerals, or other contaminants in the feedwater can affect the steam's thermal properties, leading to issues such as scale formation or carryover of water droplets into the steam system, which further deteriorates steam quality.

Other options do not encompass the critical elements for steam quality as effectively as the correct choice does. Factors like fuel type and humidity do not directly control steam quality; while they might influence other aspects of a boiler's operation or efficiency, they are not primary determinants of steam quality itself.