Sea water Reverse Osmosis DONE BY: team#4 Suood AlShehhi 4959681 Abdullmoen 4820861 Mohammed oraiqat 5296572

Reverse Osmosis overview Maintenance process Conclusion OUTLINE Introduction Reverse Osmosis overview Maintenance process Conclusion

Introduction Emirates Steel Reverse Osmosis process: Sea Water Pre-Treatment Reverse Osmosis Plant

Reverse Osmosis Overview

The main purposes of maintenance are: To reduce corrective maintenance and improve membrane performance. To reduce machine down time. To increase the life-time efficiency of the membrane. To increase the availability of the system. Efficiency of RO is 90% when all the membranes are online.

RO plant main failures Looking specifically at the RO membranes side when doing corrective maintenance. There are frequent failures for the membranes: Fouling Scaling High Iron Content (Low water quality)

Fouling Fouling of membranes is due to the suspended or emulsified materials that may be present in the feed water to the reverse osmosis system. Examples of such materials are:  silica, oil, clay, iron, sulfur and humic acids. Causes of fouling: Water hardness Pre-filter breakdown. Improper design and maintenance. Fouling can be minimized by implementing one or more of the below steps: Reduce operating pressure. (feeding water pressure). Change filters more frequently (system PPM).

Scaling Scaling means the deposition of particles on a membrane, causing it to plug. Reverse osmosis membranes and flow passages within membrane elements will scale due to precipitation of sparingly soluble gas, such as  Example : (calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate). The surface blockage of the scale results in permeate flux decline, reducing the efficiency of the process and increasing of operation costs.  There are two methods of scale control commonly employed: Acidification (acid addiction destroys carbonate ions) Ion exchange softening (this method utilizes the sodium which is exchanged for magnesium and calcium ions that are concentrated in the RO feed water)

High Iron content Iron, usually presents in groundwater as divalent ion (Fe2+) and is considered as source of membrane scaling. The antiscalant feeding before membranes is effective with respect to precipitation. It reduces iron concentration from 3.8 mg/l to 3.12 mg/l, but this iron level is still the main source of membrane problems. various treatment methods have been employed to enhance water quality by removing iron. Oxidation Processes Depth Filtration Manganese Greensand

Maintenance process According to the risk management matrix, a preventive maintenance schedule should be set to help maintain the plants efficiency.

Likelihood of Occurrence Maintenance Process (Weighted Impact Rating = Severity of Impact * Likelihood of Occurrence)   Likelihood of Occurrence Very Low Low Medium High Very High 1 2 3 4 5 Severity of Impact 6 8 10 9 12 15 16 20 25

Maintenance Process Weighted Impact Value Asset Value 1 2 3 4 5 6 8 9   Weighted Impact Value 1 2 3 4 5 6 8 9 10 12 15 16 20 25 Asset Value Very Low Low 18 24 30 32 40 50 Medium 27 36 45 48 60 75 High 64 80 100 Very High 125>

Risk Rating Impact of Risk Tolerance Level Very Low >=1 & <10 Requires to be attended to after low risks as it may have negligible impact on the business Can be accepted without any or further controls being implemented Low >=10 & <20 Requires to be attended to after medium risks as it may have minor impact on the business Medium >=20 & <40 Requires to be attended after high risks as it may have an impact on the business Can be addressed by using a combination or existing controls and some additional controls. May or may not require additional finances High >=40 & <64 Requires to be attended after very high risks as this may have a major impact on the business High risks to be addressed by using a combination of existing controls and some additional controls. May require some finances Very High >=64 Requires to attended immediately as it may have a significant impact on business Very high risks to be addressed by using a combination of existing controls and some additional controls. May require substantial finances

Maintenance Process Applying Preventive maintenance: The efficiency of the RO system very low when any of the failures occurs. This indicates for the operators to increase the frequency of the maintenance to maintain the resource efficiency. By doing so the following will be enhanced: Efficiency, reliability, and availability of Sea Water RO improved significantly Efficiency : 90 - 95% Reliability: 85 - 90% Availability: 90 - 95%

FIND OUTS Preventive maintenance helps in: Equipment downtime is decreased and the number of major repairs are reduced. Quality & safety improvement. Enhances the efficiency of equipment. Reduces the chance of emergency repair calls.

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