Recommended Procedure for Collecting and Analyzing Deposits

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=100 BGCOLOR="#CCCCFF" TEXT="#080000" bgproperties="fixed" background="0d200640egdysm.jpg"> <div> <FONT SIZE="6" COLOR="#000066" FACE="Arial" ><B>Jonas, Inc.</B></FONT><FONT SIZE="5" COLOR="#000099" FACE="Arial" ><B> </B></FONT><FONT SIZE="1" COLOR="#000099" FACE="Arial" ><B>   </B></FONT><FONT SIZE="3" COLOR="#000099" FACE="Arial" ><B> |</B></FONT><B>     </B><A HREF="index.htm" TARGET="_top" TITLE="Jonas, Inc."><U><B>Home</B></U></A><B> </B><B> </B><B>   </B><B> |    </B><A HREF="contact.htm" TARGET="_top" TITLE="Contact Us"><U><B>Contact Us</B></U></A><B>                                           </B></div> <div> back to<B>  </B><A HREF="procedures.htm" TARGET="_top" TITLE="Recommended Procedures"><U><B>Recommended Procedures</B></U></A><FONT SIZE="3" COLOR="#000099" FACE="Arial" ><B>                                                                                         </B></FONT></div> <div> </div> </td> </tr><tr> <td valign="top" width=155 BGCOLOR="#0000BF" TEXT="#F7F7FF"> <div> <B><IMG BORDER="0" SRC="Symb075c00b700c8ffcccc00.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Recommended Procedure for Collecting and Analyzing Deposits</B></div> <div> <A HREF="grab_sample.htm" TARGET="_top" TITLE="Water and Steam Grab Sample Procedures"><U>Water and Steam Grab Sample Procedures</U></A></div> <bR> </td> <td valign="top" height=380 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <B>Recommended Procedures for Collecting and Analyzing Turbine and other Deposits</B></div> <div> <B>Objectives</B></div> <div> Identify corrodents in the system, determine sources for impurities, and perform a blade path audit to find efficiency and MW losses in the turbine.</div> <div> <B>Background</B></div> <div> Collection and analysis of turbine deposits is an important part of the evaluation of a unit's water and steam chemistry.  It can identify the corrodents which are present in the system and help to determine the sources of impurities.  This analysis can also be used as part of a Blade Path Audit to determine the efficiency and MW losses for each stage of the turbine.  Additional information on Blade Path Audits can be found at:  <A HREF="blade.htm" TARGET="_top" TITLE="Steam Turbine Blade Path Audit"><U>www.steamcycle.com/blade.htm</U></A>. </div> <div> For these reasons, proper techniques and adequate documentation are critical for description, collection, and analysis of deposits.  If not sampled properly, the deposits could be contaminated, there may be insufficient quantity for the required analysis, or inadequately or incorrectly identified.  To avoid these problems, Jonas, Inc. has developed the following procedure for documenting and collecting deposits. </div> <div> Typical steps:</div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Photograph, video and visually examine the turbine (look at deposit distribution, flow markings, signs of washing, drying, corrosion, erosion, etc.)  </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Measure the in-situ pH of the deposits </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Record the deposit thickness and distribution on airfoils and other surfaces  </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Collect deposits </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Optical and Scanning Electron (SEM) microscopy to determine deposit morphology </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Semi-quantitative and quantitative analysis (elements, ions, SiO2, TOC/TIC, etc.) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">X-ray Diffraction (XRD) (to determine chemical compounds) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Loss on Ignition (to determine the amount of organic matter) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Infrared Spectroscopy (IR), Gas Chromatography/Mass Spectroscopy (GC/MS) for organics) </div> <div> The results of the turbine deposit analyses should be recorded and preserved for the service life of the turbine because often, corrosion damage is discovered many years after the chemical upsets which caused it.  These records can help trace the corrosion history of the turbine and of the entire system.    </div> <div> <B>Documentation and Collection of Deposits from Turbine Blades</B></div> <div> Deposits should be collected during every opening or disassembly of the turbine. Care should be taken to preserve turbine blade deposits without contaminating them with dirt, cleaning fluids, lubricants, etc.  Deposits should be collected as soon as possible after each section of the turbine is opened. This will reduce the possibility of contamination. </div> <div> Ideally, both overall and closeup photographs and deposit samples would be obtained for each stationary and rotating stage of the HP, IP and LP turbine sections.  Since this is not always practical, as a minimum, four locations should be sampled. They are: </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">high pressure turbine control stage</div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">intermediate pressure section </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">low pressure turbine blades </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">the blade row before the saturation line (L-1 rotating blade in fossil utility turbines) </div> <div> Deposit samples should be scraped off with a clean stainless steel knife or spatula onto a piece of clean hard paper.  The entire deposit should then be placed in its own clean plastic bag or vial.  If there is insufficient deposit to scrape off, a wipe sample can be obtained using a piece of clean filter paper while wearing clean plastic gloves.  The filter paper containing the wipe sample should then be placed in a clean plastic bag or vial. The quantity of deposit required for analysis is specified in the following section. </div> <div> The sample container should be labeled with the Plant and Unit number, the blade row identification and location on the blade where the sample was taken (leading edge, root, trailing edge, etc.), and the date and time it was sampled.</div> <div> In order to ensure there is enough sample for all the analyses which will be performed, a minimum of 1 gram (~1 cm^3) should be obtained from each location sampled.  This can usually be accomplished by combining samples from several blades on the same stage. </div> <div> In-situ pH of the deposit should be measured using a fine division pH paper.  The pH paper is placed on the deposit and wetted with an eye dropper using the best available laboratory water (ASTM Grade 3).  The resulting color on the pH paper is then compared with the color scale on the pH paper dispenser and the pH is recorded. </div> <div> The deposit thickness should be measured, if possible, using a micrometer, calipers, or by comparison to a filler gage.  If any pitting is present, the location and average depth of the pits should be recorded, along with a photograph of the pitted areas, cracking, erosion, foreign object damage (FOD), etc. </div> <div> An alternative to manual sampling of turbine deposits is to use a <A HREF="kit.htm" TARGET="_top" TITLE="Deposit, Scale and Powder Collection Kit"><U>Deposit, Powder, and Scale Collection Kit</U></A> which includes a small vacuum, sample bags, and a deposit scraper.  The turbine deposits are scraped off and immediately vacuumed up and collected in a sample bag.  This makes collection much easier and reduces the possibility of contamination. </div> <div> <B>Analysis of Turbine Deposits</B></div> <div> The following analyses can be performed: </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Visual examination with macro photograph and description of the deposit color and consistency</div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Optical microscopy and Scanning Electron Microscopy (SEM) examination with photographs at low and high magnification. Description of the deposit morphology, color and size of particles </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Semi-quantitative elemental analysis using Energy Dispersive X-ray Spectroscopy (EDS) (a minimum of 10 mg is required) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Quantitative determination of important elements and ions (Na, Cl, SO4, PO4, Ca, Mg, Fe, Cu, SiO2,TOC/TIC, etc.) using ICP, ion chromatography, atomic absorption, spectrophotometry, etc. (each type of analysis requires approx. 100 mg) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">X-ray Diffraction identification of crystalline species (a minimum of 50 mg is required) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Loss on Ignition to determine the amount of organic matter (a minimum of 100 mg is required) </div> <div> <IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">If organics are expected to be a part of the deposit, Infrared Spectroscopy (IR) can be used to identify the organic compounds which are present. </div> <div> If only a wipe sample is available, Items 1 to 3 still provide valuable information. All standard chemical analytical methods are described in ASTM D2186 "Standard Test Methods for Deposit-Forming Impurities in Steam" and Volumes 11.01 and 11.02 of the Annual Book of ASTM Standards. </div> <div> <B>Collection of Turbine Deposits without Turbine Disassembly</B></div> <div> Listed below are several devices which collect deposits representative of what is found in the turbines:  </div> <div> <A HREF="deposit.htm" TARGET="_top" TITLE="Turbine Deposit Collector / Simulator"><U><IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Turbine Deposit Collector/Simulator</U></A></div> <div> <A HREF="dryprobe.htm" TARGET="_top" TITLE="Turbine Moisture Drying Probe"><U><IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Drying Probe</U></A></div> <div> <A HREF="devices.htm" TARGET="_top" TITLE="Monitoring Devices"><U><IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Early Condensate Collector</U></A></div> <div> <A HREF="devices.htm" TARGET="_top" TITLE="Monitoring Devices"><U><IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Converging - Diverging (C-D) Nozzle</U></A> </div> <div> <A HREF="devices.htm" TARGET="_top" TITLE="Monitoring Devices"><U><IMG BORDER="0" SRC="Symb075c00b700c800000000.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">Converging Nozzle</U></A> </div> <div> The deposits collected from each of these devices can be analyzed to determine the amount and composition of impurities depositing in the turbine. </div> <div> <B>Collection of Deposits from Other Components</B></div> <div> When collecting deposits from other system components, the same procedures and analyses can be used as described above. Typical components where deposit collection is useful include: gas turbines and compressors, boiler, superheater and reheater tubes, feedwater heaters, condenser, and piping. </div> <div> <B>References</B></div> <div> "Standard Practices for Sampling Water-Formed Deposits." Annual Book of ASTM Standards. Volume 11.02. American Society for Testing and Materials. ASTM D887-82. </div> <div> "Standard Test Methods for Deposit-Forming Impurities in Steam." Annual Book of ASTM Standards. Volume 11.02. American Society for Testing and Materials. ASTM D2186-84. </div> <div> O. Jonas. "On-line Diagnosis of Turbine Deposits and First Condensate." Proceedings: 55th Annual Intl. Water Conference. Pittsburgh, PA. Oct. 31 - Nov 1-2, 1994. </div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="150bf4f0.gif" border=0 width="447" height="79" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <bR> </td> </tr></table></body>