TY - JOUR
TI - Waste heat potentials in the drying section of the paper machine in Umka Cardboard Mill
AU - Jankes Goran G
AU - Tanasić Nikola
AU - Stamenić Mirjana
AU - Adžić Vuk M
JN - Thermal Science
PY - 2011
VL - 15
IS - 3
SP - 735
EP - 747
PT - Article
AB - Paper production is one of the most energy intensive industrial processes.  The use of waste heat is very important for energy efficiency improvement in  paper industry. This paper deals with methods for calculation of potentials  of waste heat generated in paper/board production process. For that purpose,  the material and heat balance of the cardboard machine at Umka Cardboard Mill  has been determined. Field measurements were conducted in order to define the  unknown values of process parameters used for calculation in the balance  equations and modelling. The focus was given to the cardboard drying section,  which consumes most of the energy supplied to the machine. Additional aim of  the work presented in the paper was to evaluate the specific energy  consumption and the thermal efficiency of all individual energy units within  the machine’s drying section. The results indicate two main sources of waste  heat: waste heat released to the atmosphere with the discharge air from the  present waste heat recovery system (14,380 kW); and waste heat released into  the hall from the machine and extracted by the hall ventilation system (4,430  kW). Waste heat from both sources is characterized by fairly low temperatures  58-75ºС and fairly high moisture content (30-40 g/kg). The waste heat can be  partly utilized for preheating the fresh air in cardboard drying process,  saving up to 13% of steam consumption. The specific heat consumption and  specific steam consumption (consumption per tonne of produced cardboard) of  the machine was 1,490 kWh/t and 1.4 t/t, respectively. The thermal efficiency  of drying section and coating drying section was 55.6% and 33.6%,  respectively. All these figures imply necessity for further waste heat  utilization with the aim of improving the efficiency of energy use.