Total site centralised water integration for efficient industrial site water minimisation

Abstract

Water is used in process industry for a wide range of applications. Water minimisation has received growing attention due to stricter environmental regulations and scarcity of quality water. Rising price of fresh water and cost of wastewater treatment, as well as the relation with the energy (generating emissions) needed for preparing and supplying water, have created an urgent need for efficient water utilisation, especially in the industrial sector. Demand for clean water has been rapidly growing also in the commercial and domestic sector, and very substantially in the agricultural sector. In some regions, water has become a strategic commodity that is even more important than energy. Numerous research works have been performed on Total Site Water Integration (also known as Interplant Water Integration in some papers). However, a superstructure that considers all possibilities of water exchange among sources and demands in industrial sites or a region, are practically challenging to implement since most plants prefer to keep their data and processes confidential. The cost of piping and pumping can be very high due to the need to transfer water across complex industrial water networks. In this study, the option of using centralised headers managed by a third party is explored for a simpler and easy to manage water reuse and recycling among plants. Two centralised water reuse headers with different wastewater quality range, located along a set of plants are proposed. A new Pinch Analysis methodology known as Total Site Centralised Water Integration (TS-CWI) to target the minimum freshwater requirement and wastewater generated resulted from the integration of plants with this centralised water reuse headers are presented. The methodology is illustrated with a case study with 55.1 % of reduction of freshwater requirement and 54.7 % of reduction of wastewater generated.