Assessment of Long-Distance Thermal-Energy Transport: A Comparison Between Water, Steam, and Hot Oils

摘要

An assessment of the capital and operating costs required to supply low-to-moderate temperature (120 exp 0 to 250 exp 0 ) thermal energy via a long distance pipeline system is presented. Ten basic thermal energy systems are studied in this report; 6 systems subdivided into 54 cases covering single-medium energy outputs, and 4 systems subdivided into 36 cases covering multimedium (2 or more different forms, such as steam and hot water) energy outputs. Preliminary sizing calculations were performed and basic design requirements were developed for each of 9 cases in each of the 10 systems. The 9 cases in each system involved short (8 km), intermediate (24 km), and long (64 km) transport distances as well as low (273 GJ/hr), intermediate (1370 GJ/hr), and high (4100 GJ/hr) levels of heat input. Thermal-energy delivery costs are computed for each case to determine which systems are most economical to construct and operate. Three different types of energy output were selected for study. These outputs are: 1, hot water at 120 exp 0 C; 2, saturated steam at 177 exp 0 C; and saturated steam at 249 exp 0 C. These outputs were selected because hot water at 121 exp 0 C can be used to supply building heat and to heat hot water for industrial or residential use; saturated steam at 177 exp 0 C is commonly used for industrial and commercial purposes as process heat as well as being used in to heat buildings and hot water; and saturated steam at 249 exp 0 C is commonly used industrially for higher temperature process heat as well as being used in turbines and piston engines for mechanical drives. (ERA citation 04:034454)