Ökad matarvattentemperatur vid biopannan Smurfit Kappa Piteå : Increased feedwater temperature at biomass boiler Smurfit Kappa Piteå

• Main Author: Hedström, Anton
• Format: Bachelor Thesis
• Language: Swedish
• Published: Umeå universitet, Institutionen för tillämpad fysik och elektronik 2018
• Subjects: Energy Engineering; Energiteknik; Piteå
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-148589

Smurfit Kappa Piteå is the largest kraftliner producer in Europe. At the mill they have five different steam producers and one of those is the biomass boiler, which is a steam boiler producing overheated steam at 120 bar and 520C. The purpose of this report is to investigate the possibilities to increase the feedwater temperature from today’s 180C to 210C. The consequences on the system are depending on the temperature in the different process stages and the process temperatures are therefore calculated via a method named The NTU-method which is a suitable method to analyze the heat transfer within an object when the ingoing and outgoing temperature are unknown. The feedwater is preheated with a heat exchanger that is heating the feedwater from 130C to 180C using steam with a pressure of 11 Bar. To increase the temperature to the desired the approach is to install a complementary feedwater heater that uses steam with a pressure of 27 Bar. The new heater is supposed to heat the feedwater from 180C to 210C while the old heater takes the temperature from 130C to 180C. If the old heat exchanger approaches its end of life span it may have to be replaced with a new one with the same design data. One way to fulfill the required heating is to install one feedwater heater that takes the temperature from 130C to 180C using steam with a pressure of 11 Bar and in the next step install the second feedwater heater that takes the temperature from 180C to 210C using steam with a pressure of 27 Bar. There are two alternatives to installation of complementing high pressure heat exchanger. First alternative A is to install the second feedwater heat exchanger between the economizer and the steam dome. Second alternative B is to install the second feedwater heat exchanger between the already existent heat exchanger and the economizer. The consequence of the installation B is an increased energy loss due to the combustion gases while the consequence of installation A does not involve any increase in energy losses. Therefore, ...