Energy saving in the tissue industry: technical and economic aspects of a case study

In this paper, a detailed description of a project designed to reduce the energy consumption in a tissue mill in the Lucca industrial district (Italy) is presented: both technical and economic aspects have been thoroughly considered. First of all, an accurate analysis of the status of the previous steam plant for the paper drying process was developed, to identify possible improvement opportunities; then a new configuration for the steam system was proposed and designed. After that, by means of a comprehensive feasibility analysis, the typical economic indices were calculated assuring good economic profitability of the plant modification investment. The modifications to the system make it possible to achieve consistent annual savings of natural gas, fresh water and CO2 emissions through complete elimination of steam losses that were present in the original steam circuit. Implementation of the new steam system has fully confirmed the design results described in this paper.