Heat mildly corrosive solutions (pH5 to pH9) using stainless elements and a passivated stainless pipe body. Low watt density INCOLOY® sheath elements coupled with a passivated Stainless Steel pipe body provides long service life when heating highly corrosive solutions and sulfur laden oils. INCOLOY® elements and a Stainless Steel vessel enhance safe operation to nearly 1400°F outlet gas temperature in air, gas, or steam superheating applications.