Optimization of the scheme of preparing demineralized water at the existing machine building enterprise

Summary

Machine building industry needs demineralized water for moisturizers, washing and other processes. To prepare demineralized water the method of reverse osmosis is used. The advantages of this method of water demineralization are as follows: low chemical consumption, compact size of the plants and possible flexibility of the process automation. Considering the scale of reverse osmosis use and diversity of the solvable problems designing a versatile installation meeting all the requirements is practically impossible and economically unjustified. It is evident that engineering calculations and design adaptation shall be carried out in each case. An example of upgrading the demineralization scheme with the purpose of improving the capacity and conditioned water quality is presented. The result is achieved by the use of the two-stage reverse osmosis scheme that provides for the minimum chemical costs during the operation. The modernization of the facilities was carried out in continuous-duty service. Half year operation of the upgraded two-stage scheme the sustained quality of the demineralizaed water has been observed.

Key words

reverse osmosis , membrane module , permeate , two-stage scheme , water demineralization

Evaluation of full-scale reverse osmosis unit operational parameters

Summary

Undissolved and dissolved substances present in the water supplied to a reverse osmosis unit can form deposits. To minimize their negative effect the equipment for water pretreatment that ensures the water quality meeting the requirements set by the membrane elements manufacturers has been retrofitted into the general process flow scheme. The basic operational parameters of a full-scale reverse osmosis unit with spiral wound reverse osmosis elements are presented. Mathematical processing of the operational parameter values was carried out, the results gained were plotted. The changes in the operational parameters before and after chemical washing of the membrane elements are shown. The evaluation of the convergence of the design and actual data under the conditions considered is given. The quoted relationships allow evaluating the operational parameters of the membrane elements, determining the washing interval and efficiency of the chemical washing. The use of the presented method of evaluating the operational characteristics will also allow substantiating the warranty claims to the manufacturers of reverse osmosis units and membrane elements.

Key words

reverse osmosis , desalination , membrane technology , permeate , chemical washing , membrane element