Importance of Water Treatment Testing
The purpose of feeding water treatment chemicals is to avoid unscheduled outages, and prolong the life of the steam generating and cooling equipment. By reducing the potential for scale and corrosion to occur, outages can be avoided, and treatment costs can be kept to a minimum. To control overfeeding or underfeeding of water treatment chemicals and to detect water impurities it is necessary to have thorough water treatment testing. However, to be of immediate value, water treatment testing must be safe, easy to perform, accurate, and involve a minimum amount of unnecessary reagent measuring and disposal. The use of water treatment testing procedures from Drew Marine provides this immediate value and helps in achieving the greatest equipment life and the least unscheduled outages.
Simply stated, if there is no monitoring of the water treatment program, there is no management of the water treatment program.
Significance of Water Sampling
The goal of sampling water for testing is to obtain a portion of the main body of water that is truly representative of the conditions existing at the point taken. A grab sample represents the conditions existing only at the point and time of sampling. Test results are meaningful only when the sample is representative of the water in the system at the time of testing.
Testing is the review of the water treatment program performance on a continuing basis to determine whether the program is achieving the established objectives. Proper sampling and testing ensures that:
- Products are performing as expected
- Changes in water chemistry have not affected product performance
- Changes in system operation (mechanical, temperature, etc.) have not affected product performance
- System performance is being maintained and to make proper judgement if chemical technology or mechanical changes need to be made
Recommended Location For Sampling Connections
Boiler Water Sampling
Normally the sampling connections provided by the boiler manufacturer can be used. The sampling line is usually located in the steam drum, just above the generating tubes. In order to get proper results, it should be as far as possible from the internal feedwater line and the chemical feed line.
Samples drawn for routine boiler water tests should be tested ONBOARD THE VESSEL. Boiler water samples for laboratory analysis need to be taken only in special cases.
Condensate and Feedwater (Condensate plus Makeup Water) Sampling Stainless steel sampling lines should be installed at three locations:
- Directly after the Main Condensate Extraction Pump. This line is to be used when the plant is under normal steaming conditions.
- Directly after the Auxiliary Condensate Extraction Pump. This line should be used only when the plant is under port operating conditions.
- The deaerator outlet line or from the suction or discharge of the main feedwater pump.
The latter is the best position for samples drawn for iron and copper tests; these samples will give a direct indication of the amounts of metal oxides entering the boiler with the feedwater. These connections may also be used for obtaining samples for dissolved oxygen tests.
On motor vessels or LPSG’s, condensate samples should be taken after the condenser or condensate cooler and before the fee or cascade tank to avoid recirculation from the feed pump.
Makeup Water Sampling
The sampling line for this water may be located in one or two positions:
- In the line between the distilled water storage tank and the point of entrance of makeup water to the condensate system.
- Directly from the distillate condenser.
Sampling Equipment
Before testing, the boiler water, hot condensate and feedwater samples must be cooled to 25°C (77°F) by collecting through a sample cooler for safety and to prevent flashing which concentrates the sample. A stainless steel sample cooler (PCN 4121-01-8) should be used except where seawater is used for cooling. Where seawater is the only coolant, a cooling coil made of INCONEL1 (PCN 1AA2128) will be required.
Stainless steel piping or tubing used for sample lines should be installed with the least possible number of fittings and/or sharp bends. This is a precaution against plugging the lines with solid contaminants. Stainless steel is recommended to prevent contamination of the sample by corrosion from the lines.
Benefits of Using Drew Water Treatment Testing
Drew Marine provides accurate, reliable, safe and easy to use water treatment test procedures that complements our water treatment chemical programs.
Drew Marine Water Treatment Testing Provides:
> Ampoule Methodology Test Kits
- Long Shelf Life
- Safe to Use
- Minimal Operator Exposure to Chemicals
- Accurate Results
- Simple to Use with Clip Art Instructions
- Minimal Equipment to Handle
- No Reagent Disposal
> Self Contained Drop Count Titration Methodology Test Kits
> Proper Dosage of Chemicals
> Shipboard Water Treatment Manual
>Well Trained Worldwide Service Engineers
> Regional Technical Support
> Corporate R&D and Product Management Expertise
The Drew Marine water treatment testing methods have taken analytical chemistry from the laboratory to the engine room providing ease of use while not sacrificing reliability.
WW-4 (11/03)
|
|
Drew Marine
One Drew Plaza, Boonton, NJ 07005 USA
Tel: (973) 263-7600 FAX: (973) 263-4491/7463
|
|
2003 Ashland Inc.
®Registered trademark of Ashland Inc. TMTrademark of Ashland Inc.
*Responsible Care and the Responsible Care logo are registered service marks of the American Chemistry Council in the U.S., of the Canadian Chemical Producers' Association in Canada and of different entities in other countries. 1Registered trademark of Huntington Alloys.