Boosting Ammonia Plant Performance - Heat Exchanger Updating
Heat exchangers make up the largest number of equipment items for older as well as modern Ammonia plants. Each of the
heat exchanger services in a plant performs an important role, including Process Gas Heating and Cooling, Gas
Compression Heat Recovery, Process Waste Heat Recovery, Steam Generation, Boiler Water Heating, Reactor Preheat and
Reaction Heat Recovery, Process Gas Chilling with Product Condensing, Gas Cooling with Steam Condensing, Steam
Turbine Exhaust Condensing, Vapor-Liquid Separation Column Reboiling, Solvent Heating and Cooling, Lube Oil Cooling and
Refrigerant Vapor Condensing. Various types of heat exchangers used in ammonia plants are described, including
exchanger equipment construction and baffle arrangements, typical operating problems and solutions, and the technical and
economic impact due to fouling, overload and excessive fluid pressure loss.
Heat exchangers make up the largest number of equipment items for older as well as modern Ammonia plants. Each heat
exchanger service in the plant performs an important role, which may include Process Gas Heating and Cooling, Gas
Compression Heat Recovery, Process Waste Heat Recovery, Steam Generation, Boiler Water Heating, Reactor Preheat and
Reaction Heat Recovery, Process Gas Chilling with Product Condensing, Gas Cooling with Steam Condensing, Steam Turbine
Exhaust Condensing, Vapor-Liquid Separation Column Reboiling, Solvent Heating and Cooling, Lube Oil Cooling and
Refrigerant Vapor Condensing.
The vast numbers of Ammonia plants in North America were built 25-35 years ago, at a time when the price of energy was
less than one third of modern energy cost. Thus, the original technical design basis for older plant equipment, including heat
exchangers, permits some substantial opportunities for improvements in efficiency and capacity when individual items of heat
exchanger equipment develop failures, demanding replacement for maintaining plant operation. New designs for replacement
heat exchangers add lasting value to the plant operation through reduced gas pressure loss, higher throughput for given
pressure loss, greater heat transfer or sometimes combinations of these benefits, reducing production costs. Sometimes
plants prefer to stick with what has worked well over many years, including some improved features into replacement
equipment, while at other times, historic equipment performance dictates the need for improved designs with specific features
to replace older equipment concepts to overcome reliability or deteriorating performance issues.
