South African chemical plant is latest ultrapure boiler feed application for Evoqua’s Ionpure® CEDI modules
The latest demineralization technology successfully packed high flow capacity into a small footprint at a South African synthetic fuels and chemicals plant, as a system of Ionpure® continuous electro-deionization (CEDI) modules was shipped, ready-to-run, in a 20ft container.
The self-contained, clean technology approach was adopted as the practical answer to a request for a fast turnaround, from initial order to installed operation. The project was managed by Proxa (Pty) Ltd, a specialised water solution provider of sustainable water services within the municipal, industrial and commercial sectors. The company was contracted by Sasol Synfuels (Pty) Ltd to upgrade a pre-existing feed water process using reverse osmosis (RO). By switching to CEDI from traditional, mixed bed deionization, Proxa was able to eliminate Sasol’s requirement to use and dispose of regeneration chemicals at the demineralization stage.
Wet sulfuric acid
Netherlands-based Pure Water Group prefabricated the containerized system for delivery to a site in Secunda, producing wet sulfuric acid using hydrogen sulfide gas from a Rectisol® acid gas scrubbing system. Recently installed and commissioned by Proxa, the 100m3/hr CEDI plant applies a final polish to the water feeding a medium pressure boiler, which provides process steam to a cracking plant.
Pure Water Group factory-tested the CEDI system, which integrated six Ionpure VNX55-EP modules with a booster pump and sand pre-filtration vessel on a skid platform. Installed in the modified 20ft shipping container, the system was perfectly adapted to road and sea transport, facilitating a smooth installation and start-up on site.
Proxa specified the stand-alone unit with inside battery limits to include feed, product, power and control interfaces. They prepared the installation site ready for delivery of the container, allowing the CEDI system to be up and running within five days of arrival.
Fed by the pure water plant’s RO permeate, the modules deliver the specified high purity stream of less than 0.5µS/cm conductivity, at an average rate of 2400m3/day. The water is pumped to a pure water holding tank, although due to the 24-hour boiler operation, the CEDI modules must also sustain 100% availability.
Designed to meet extremely low sodium, chloride and sulfate specifications, along with greater than 95% silica and boron removal, the Ionpure VNX55-EP modules selected for the Sasol project can consistently produce a 0.1 µS/cm conductivity (10 Megohm-cm resistivity) measure of product water quality.
As an Ionpure ‘Master Service Provider’, Pure Water Group is extremely experienced in supplying high purity and ultrapure water applications featuring CEDI systems. The company was involved in shaping the requirements of an Enhanced Performance (EP) module, with a wide tolerance for feed water hardness and quality variation, which resulted in the development of the Ionpure® VNX55-EP module.
The Ionpure brand is synonymous with sustainable, post-RO electrochemical solutions for industrial, power generation, pharmaceutical, high purity, and reject water recovery. The new enhanced performance VNX and LX modules continue the Ionpure brand tradition of continual improvement to retain leadership in water purification technology.