Combustion of sewage sludge in a fluidized bed of catalyst: ASPEN PLUS model

Highlights: • The plant for sewage sludge combustion (6 tons/hour) is simulated using ASPEN Plus. • The technology enables to combust of sludge with moisture of 75% in autothermal mode. • The plant for utilization of sludge allows one to obtain 3.07 MW of heat energy. This paper presents the results of the simulation of a sewage sludge combustion plant with a productivity of 6 tons per hour using the ASPEN Plus. It is shown that catalytic combustion technology can be used for the efficient utilization of mechanically dehydrated sludge with the moisture of ~75% in autothermal mode (without the use of additional fuel). At the same time, the plant for utilization of 6.0 tons of sludge per hour enables us to obtain 3.07 MW of heat energy. It is shown that the sludge moisture and its calorific value significantly affect the combustion process. Thus, at the moisture of less than 72%, additional water supply is necessary to avoid overheating of the catalyst bed. In the case of an increase in sludge moisture of more than 76%, an additional supply of fuel (for example, brown coal) is required. Also, the article discusses the emissions of harmful substances generated during sewage sludge combustion and methods for their utilization.