KOC Sulaibya ZLD reference plant
Zero Liquid Discharge (ZLD) Solution
New, strict environmental rules around the world very often impose the requirement of treating reject waters coming from water treatment plants or other industries, where water is used, to achieve zero liquid discharge instead of disposing it back to the sea/other natural reservoir. AquaSwiss offers Zero Liquid Discharge solution using its differentiating low temperature, low chemical footprint, cost effective thermal technologies. Below are descriptions of Concentrator and Crystallizer used in the AquaSwiss ZLD solution: 1. Concentrator: A Multi Effect Distillation (MED) or Mechanical Vapour Compression (MVC) evaporator positioned as the first stage of the process,. There may be a fit-for purpose pre-treatment before entering the Concentrator, such as DAF, Clarifier, Filtration etc to obtain pure water as a final product and highly concentrated brine, which is normally disposed as a waste. The product water can be designed to have any TDS from 5 ppm to 1’000 ppm dependent on the application of product water. Multi Effect Distillation (MED) Low temperature multi effect distillation is a simple, reliable and efficient process utilizing low cost / low grade heat or waste steam. Vacuum enables operation at unparalleled low distillation temperatures (below 70 °C) minimizing scale and corrosion, and hence maintenance, to an absolute minimum. A large number of effects consequently results in very high economy ratios (product to steam) and the use of aluminum tubes improving the heat transfer results in lower investment cost compared to conventional high temperature processes. With extremely safe evaporators, evaporation and condensation are achieved by direct transmission of latent heat, avoiding sensible heat pickup, which would decrease the effective temperature differential. Using the falling film concept, static head is eliminated from the flashing process and high evaporation heat transfer coefficients result. AquaSwiss uses all standard items of equipment in the plant of high quality and reliable design, purchased only from reputable international manufacturers.
Mechanical Vapour Compression (MVC) MVC distillation is the most thermodynamically efficient process of single-purpose thermal desalination. The thermodynamic efficiency is derived from the application of the “heat pump” principle by a large volumetric flow compressor acting as the “heat pump”, which continuously recycles and keeps the latent heat exchanged in the evaporation and condensation steps within the system. The heat required to evaporate part of the processed feed, which flows on one side of a heat transfer surface, is supplied through the simultaneous condensation of the distillate, on the other side of the surface. This cycle of evaporation and condensation operates continuously. The principle is similar to our MED. MVC units are standard, factory-assembled and skid mounted units, proven by strict and thorough prototype testing at an R&D centre and by years of satisfactory experience with commercial plants operating throughout the world. The plants are simple, efficient and automatic. The quality of the product water from the MVC unit exceeds public health standards by a wide margin. Typical applications are for downstream oil companies, oil facilities, refineries, petrochemical plants, industries like cement, tourism, factories, chemical plants etc.