0.2t. The discharge rate of a steam boiler is generally about 1 of the evaporation capacity. The discharge volume of a 20-ton steam boiler is 20×1=0.2t. The water consumption of a 20-ton steam boiler is 2.2t and the displacement is 0.2t. Gas-fired steam boilers refer to steam boilers that use gas combustion for heating. Vertical steam boilers adopt a bottom-mounted burner and a two-pass structure. The fuel is fully burned, the boiler operates stably and takes up less space. At the same time, a spoiler is inserted into the smoke pipe to reduce the energy consumption. The smoke exhaust speed increases the heat transfer, the boiler thermal efficiency is high, and the user cost is reduced.