Energy consumption in equivalent work by different desalting methods: case study for Kuwait

Kuwait needs to add more desalting units to its present installed capacity to satisfy the growing need of potable water. The energy consumed by different desalting system is one of the main parameters affecting the choice of new desalting system. Every desalting system consumed either thermal, or mechanical energy or both. This paper presents a method to compare these energies on one scale that the equivalent work consumed. Based on this analysis, the energy consumed by the multi stage flash MSF system, the only system presently used in Kuwait to desalt seawater, was calculated and found equal to 25 kWh/m(3). This is much higher than the energy consumed by the other two reliable systems, namely reverse osmosis (RO) and multi-effect boiling (MEB) extensively used now in many of the Arabian Gulf Countries, AGC. The average energy consumed by the RO system is 5 kWh/m(3), and by the MEB is in the range of 12 kWh/m(3) when steam is extracted from steam turbines at low availability.