Evaporation Evaporators, Evaporator, Evaporator Coolers, Crystallisers, Crystallisation, Fluid Bed Dryer, Rotary Dryer, Distillation Plant, Absorption Plants, Scrubbers, Fuel Gas Scrubber, Gas Scrubber Systems, Water Filtration, Water Filtration Systems, Membrane Processes, Air Cooled Heat Exchangers

Ammonium Sulphate Reaction Crystalliser
	The client produces sulphuric acid from an environmental gas cleanup project. It was decided to convert this acid into ammonium sulphate through the installation of a DTB type crystalliser. This unit was designed by Process Plant Technology in South Africa and comprises acid and gas injection directly within the crystalliser. The resulting ammonium sulphate is crystallized within the body of the vessel and special features are incorporated to assist in the growth of large crystals. The crystalliser successfully produces the bulk of the crystals in the size range of 1.0 to 2.4mm. Fines destruction features are incorporated to assist in maintaining the size range of the population by minimising the growth of superfine crystals, and transferring this growth onto the larger crystals. The product is centrifuged using pusher centrifuges and then dried in a large fluidised bed dryer. This plant is completely constructed out of 316L to resist the corrosion due to the free sulphuric acid in the magma. Special design features also include complete condensation of steam generated by the reaction for recycle to the crystalliser, vent scrubbing to ensure no harmful emissions to atmosphere, and an extended fluid bed dryer for cooling of the product to below 50°C.

Nickel Sulphate Crystalliser
	One of Process Plant Technology’s main strengths is the design and construction of crystallisers in a variety of different applications. In this instance, the client’s feed was a dilute nickel sulphate stream from a leach filtration plant. The feed also contained significant levels of free acid. The mandate was to minimize overall energy costs and the result was a falling film pre-concentrator followed by a Draft Tube Baffle (DTB) crystalliser operating under high vacuum in order to crystalliser the desired hydrated crystal. The entire plant was constructed out of SAF2205 to resist the effect of chlorides at the low pH and high temperatures experienced on the plant. The crystals from the crystalliser are dried in a circular fluid bed dryer and the final product is bagged in 1 ton bags. Special design features include a single body four stage falling film evaporator incorporating a single high lift MVR fan for high energy efficiency. Use of a DTB crystalliser enables the growth of larger crystals, improving dewatering, drying and final product quality.

Kiln Offgas Scrubber
	Process Plant Technology have recently completed a large kiln offgas scrubbing plant for a metallurgical plant in Western Australia. This plant handles 136 000Nm3/h of dirty hot offgas and includes a novel process for concentrating another process stream, utilising the energy within the offgas to evaporate the required quantity of water. The plant incorporated refractory lined hot gas cyclones for recovery of abrasive dust from the gas prior to the scrubber. All equipment was designed and fabricated in South Africa, being exported to the Western Australian port of Freemantle. The largest item, a 6.0m diameter scrubber vessel provided an interesting logistical exercise in loading in Johannesburg, transporting to Durban and shipping to Australia. The decision to fabricate in South Africa was driven by management and cost issues. The total project duration from order award to delivery of equipment was completed eight weeks ahead of schedule. The attached photograph shows the scrubber during erection.

Ammonia Recovery Plant
	In enhancing our ability to tackle new and challenging projects in the fields of heat and mass transfer, Process Plant Technology developed a novel process for stripping ammonia gas out of a mine slurry. The flowsheet generated 10% ammonia solution as a main product and achieved twice the desired ammonia stripping efficiency compared to the client specification. The plant also included extensive heat recovery in order to improve the economics of the entire process. This process has created significant interest in the industry, and a number of papers have been published on its development, one of which can be viewed at: http://www.basemetals.org.za/Kasane2009/Papers/201-214_Nel.pdf Special design features include multiple condensers for enhanced heat recovery as well as internal recirculation of dilute condensates to maximize the final product strength.