Case study: Paper mill power plant optimization—balancing steam venting with mill demand

Abstract

Most Power departments are tasked with generating steam to support mill wide operations, gener-ate electricity, and reduce operating costs. To accomplish these tasks, power boilers generate high pressure steam that is reduced to intermediate and low pressures for process utilization in the mill by means of steam turbine generator extraction or pressure reducing valves. The most economical method to reduce steam pressure is the use of steam turbine generators, as electricity is generated from the steam when it is reduced in pressure. Electricity that is produced by these generators provides a substantial financial benefit and helps offset overall operational costs. To achieve tangible financial gains, the mill must evaluate the overall cost of steam production and the price of electricity. The current work provides a case study of power plant optimization that evaluated electricity production and steam production costs balanced with mill steam demand. Process and cost optimization led to a significant reduction in low pressure steam venting, resulting in reduced fuel consumption and reduced operating cost.