Considering Direct-Contact Steam Injection?

摘要

When considering using direct-contact steam injection (DSI) for a process heating application, it is important to first understand the two basic techniques - direct and indirect transfer - used to transfer heat into fluids for process and utility heating. Indirect contact heat exchangers such as shell-and-tube, plate-and-frame or scraped-surface designs have two or more fluid flow paths to prevent the fluids from mixing. The heat is transferred from one fluid to another across a thermally conducting but otherwise impermeable barrier, such as a tube wall or plate. Direct-contact heat exchangers transfer heat by injecting steam directly into the process fluid (hence the name). This results in rapid heat transfer and often is more efficient than indirect heat exchangers. Direct-contact steam heating provides 100 percent thermal efficiency because both the sensible and latent energy in the steam are used.