Continuous Gas Analysis ULTRAMAT 23 Supplement 1 for Operating Instructions C79000-G52xx-C Product Information

Transcription

1 Continuous Gas Analysis ULTRAMAT 23 Supplement 1 for Operating Instructions C79000-G52xx-C Product Information Introduction Device model and validity This supplement describes the device, ULTRAMAT 23 with a hydrogen-sulphide sensor. The supplement only covers the specific components of this ULTRAMAT 23 version. The standard operating instructions for the ULTRAMAT 23 (C79000-G52xx-C216) as of revision 03 should be read in any case to ensure safe operation of this device. This applies, above all, to the warnings and safety information provided there. Safety information Safety information You can find additional specific safety information in the respective sections of these operating instructions. Adherence to these instructions is essential for safe handling of the device or situation described therein! DANGER Danger of poisoning This device is designed to measure hydrogen sulfide and dihydrogen sulfide, H2S)! Hydrogen sulfide is highly toxic even in small concentrations! The odor threshold for hydrogen sulfide is 0.02 vpm at (20 vpb). Persons exposed to this gas with concentrations up to 100 vpm for several hours demonstrate poisoning symptoms such as fatigue, headache, loss of appetite and lack of concentration. With a concentration from approximately 200 to 250 vpm, the olfactory receptors in the nose will be numbed so that the odor is no longer perceived. Inhalation of H2S concentrations of 500 vpm longer than 30 minutes can cause fatal poisoning. Concentrations above vpm cause death within a few minutes, concentrations above vpm cause death within a few seconds! When using this device in plant where there may be high concentrations of H2S and you therefore need to take following continual precautions to prevent the effects of poisoning: Connect the gas outlet of the analyzer to a gas exhaust unit so that no gas can escape into the environment! Before you begin maintenance on the analyzer, make sure that the H2S concentration in the analyzer is close to 0 vpm. Before beginning work, always flush the gas path of the analyzer and the gas sampler with ambient air or nitrogen for a duration of about 10 minutes. Check for leaks in the analyzer at regular intervals! DANGER Danger of explosion This device is used in biogas plants, among other places. When it is used in biogas plants, you should expect that the sample gas will contain methane, which forms explosive mixtures with oxygen or air in certain concentrations. These conditions are possible with certain operating states of the plant. To avoid the danger of an explosion, it is essential to install a flame arrester upstream of the analyzer in the sample gas line of biogas plants. Siemens, All rights reserved P 2009, 2010, 2012 A5E , 03/2012 1

2 Product information / technical updates Description Area of application This device is designed to measure H2S. Application areas include Biogas plants Sewage plants Drinking water treatment Feeding of biogas into the natural gas grid Function Measuring principle The hydrogen sulfide enters through the diffusion barrier (gas diaphragm) into the sensor and is oxidized at the working electrode. A reaction, the reduction of atmospheric oxygen, takes place on the counter electrode. A current which is directly proportional to gas concentration results on the connector pins due to the electron transfer. Figure 1 Operating principle of the H2S sensor Calibration of the measured value drift The deflection signal of the sensor is subject to drift. This drift can be detected only through regular review and corrected as needed. This involves using a calibration gas with a defined concentration of hydrogen sulfide. We recommend monthly calibration (re-adjustment) with one of the following calibration gases (depending on the measuring range) to keep potential measurement uncertainty within strict limits: vpm H2S vpm H2S 2 A5E , 03/2012

3 Gas path charts Key for gas path diagrams 1 Inlet for sample gas/calibration gas 10 Magnet valve 2 Gas outlet 11 Sample gas pump 3 Inlet for zero gas or 12 Pressure switch Inlet for sample gas/calibration gas (channel 2) 4 Gas outlet channel 2 13 Flow indicator 5 Enclosure flushing 14 Analyzer unit 6 Inlet for atmospheric pressure sensor 15 Safety condensation trap 7 Inlet chopper compartment flushing 16 Oxygen sensor 8 Condensation trap with filter 17 Atmospheric pressure sensor 9 Safety fine filter 18 Hydrogen sulphide sensor Figure 2 ULTRAMAT 23, 19" rack-mounted enclosure with internal sample gas pump and optional oxygen measurement A5E , 03/2012 3

4 Figure 3 ULTRAMAT 23, 19" rack-mounted enclosure without internal sample gas pump, with optional oxygen measurement 4 A5E , 03/2012

5 Technical data H2S sensor for measuring ranges from 500 to 5000 vpm H2S General information Measured components Measuring ranges Smallest measuring range Largest measuring range Service life of the sensor Permissible ambient pressure Permissible operating temperature Operation mode AUTOCAL Influencing variables Associated gases Cross-inferences (interfering gases) Drift Temperature Air pressure Measuring behavior Display delay (T90 time) Output signal noise Display resolution Output signal resolution Reproducibility Maximum of 4, comprising three infrared-sensitive gases, one oxygen and one hydrogen sulfide vpm vpm Approx. 12 months hpa C ( F) Continuous measurement Cyclic interval any 3 hours using ambient air The hydrogen sulfide sensor must not be used if the residual gas contains the following components: - Chlorine-containing compounds - Fluorinated compounds - Heavy metals - Aerosols - Alkaline components (e.g. NH3 >5 mg/m 3 ) 100 vpm SO2 result in a cross-interference of <30 vpm H2S < 1 % per month < 3 % /10 K relative to full-scale value < 0.2 % of measured value per 1% pressure change < 80 s with approx l/min sample gas flow 3 % of smallest measuring range with a damping constant of 30 s 1 vpm H2S 1.5 % of smallest measuring range with a damping constant of 30 s < 4 % of smallest measuring range, referred to full-scale value A5E , 03/2012 5

6 H2S sensor for measuring ranges from 5 to 50 vpm H2S General information Measured components Measuring ranges Smallest measuring range Largest measuring range Service life of the sensor Permissible ambient pressure Permissible operating temperature Operation mode AUTOCAL Maximum of 4, comprising three infrared-sensitive gases, one oxygen and one hydrogen sulfide vpm vpm Approx. 12 months hpa C ( F) Continuous measurement between 0 and 12.5 vpm Discontinuous measurement between 12.5 and 50 vpm Cyclic interval any 60 minutes using ambient air Influencing variables Accompanying gas Cross-inference (interfering gas) Drift Temperature Air pressure The hydrogen sulfide sensor cannot be used if the accompanying gas contains the following components: - Chlorine-containing compounds - Fluorinated compounds - Heavy metals - Aerosols - Alkaline components (e.g. NH3 >5 mg/m 3 ) vpm SO2 result in a cross-interference of <20 vpm H2S 180 vpm NO result in a cross-interference of <150 vpm H2S No cross-interference of CH4, CO2 and H2 (1000 vpm) < 1 % per month < 3 % /10 K relative to full-scale value < 0.2 % of measured value per 1% pressure change Measuring behavior Display delay (T90 time) Output signal noise Display resolution Output signal resolution Reproducibility < 40 s with approx l/min sample gas flow <2 % of smallest measuring range with a damping constant of 30 s 0,01 vpm H2S <1 % of smallest measuring range with a damping constant of 30 s < 4 % of smallest measuring range Note Measuring ranges The exact specification of the largest and smallest H2S ranges can be found on the label! 6 A5E , 03/2012

7 Commissioning General information Commissioning of the ULTRAMAT 23 is described in section 4 of the standard operating instructions, C79000-G52xx-C For the commissioning of the H2S channel, a special leak test needs to be performed, as it should be each time the H2S sensor is exchanged. Leak test of the H2S sensor The leak test corresponds to that of other sample gas channels. It is most easily performed by connecting a U-tube manometer to the sample gas inlet You can check for leaks as follows: 1. Block the sample gas outlet. 2. Create an overpressure of around 150 hpa (rel.) at the sample gas inlet. 3. Wait for about 60 seconds for the temperature of the incoming gas to be compensated. 4. Read the pressure on the manometer and note it 5. Wait a further 15 minutes and note the pressure again after this period. 6. Compare the two pressure values. The sample gas path is sufficiently tight when the pressure has changed by no more than 5 hpa (5 mbar) over 15 minutes. Operation General information Measuring mode After power-on and a warming-up phase, the ULTRAMAT 23 a goes through an AUTOCAL. This involves synchronization of the zero point and sensitivity of the two IR channels. When an oxygen sensor is used, its sensitivity is also compared with ambient air with a proportion of 20.95% oxygen. The hydrogen sulfide sensor is not adjusted during the course of this first AUTOCAL. The zero point of the H2S sensor is only adjusted from the second AUTOCAL onwards. Subsequently, the device enters the measuring mode and continuously measures. Since a hydrogen sulphide sensor is used with this ULTRAMAT 23 model, the device can measure a maximum of 2 IR components if an oxygen sensor is also being used at the same time. A5E , 03/2012 7

8 Operating mode In operating mode, you can view device parameters or adjust the device and set the parameters. This supplement only describes the functions relevant for operating the H2S sensor. A complete overview of all the device's control functions can be found in the standard operating instructions of the ULTRAMAT 23 (C79000-G52xx-C216-03). Press the ENTER key in measuring mode to start the operating mode. The main menu appears with the follow options. Analyzer status Calibration Parameters Configuration Diagnostic control functions H2S measuring capacity To specify the value of the H2S measuring capacity, navigate as follow in the operator menu: Diagnostics -> Analyzer status -> Measuring reserve - > H2S Measuring reserve. The following screen appears: H2S Sensor status Reading :747,OOnA Maint.Req.:373,50nA Fault : 74,70nA The H2S sensor ages with increasing operating time, thereby steadily decreasing its sensitivity. It has almost reached the end of its service life (maintenance requirement) when it has lots 50% of its sensitivity. The sensor must be replaced. If the sensitivity drops below 10%, error message S30 (sensitivity of H2S sensor outside tolerance limits) is output. Diagnostic values The displayed diagnostic values provide important information for troubleshooting and calibration tasks. To view the diagnostic values of the H2S sensor, navigate as follow in the operator menu: Diagnostics -> Diagnostic values -> Probe diagnostic values -> Choose component -> H2S. The following screen appears: Sensorsig.: 4886 na H2S : 6.5 vpm Inst. Date: Inst Curr : 747 na This dialog shows the diagnostic values of the H2S sensor. They have the following meaning: Probe current is the current pressure-corrected current of the H2S sensor in na H2S is the current hydrogen sulphide measured value in vpm. Negative values are also possible here. Date is the installation date of the H2S sensor Installation current is the pressure-corrected current per vpm H2S of the sensor at the time of installation. 8 A5E , 03/2012

9 Calibration control functions You first need to select the H2S sensor in order to adjust it. To do this, navigate in the operator menu as follows: Calibration -> Please enter code -> Calibrate probe -> Choose component -> H2S. The following screen appears: Cal after install Start zero cal. Start MR cal. Input TC parameters Now you can adjust the sensor as described in the following sections. The following sequence must be observed when calibrating the sensor: 1. Enter correction factors for temperature compensation of zero point 2. Enter correction factors for temperature compensation of sensitivity 3. Caibrate zero point of the H2S sensor 4. Caibrate measuring range of the H2S sensor 5. Enter installation date. Steps 1, 2 and 5 are only carried out when installing a new sensor. Enter correction factors of temperature compensation You use this function to enter the temperature compensation parameters for calibration of the zero point and sensitivity. To do this, navigate as follows: Calibration -> Please enter code -> Calibrate probe -> Choose component -> H2S -> Calibrate TC parameters. The following screen appears: TK Nullpkt. Eingabe TK Empf. Eingabe Temperature compensation of zero point To do this, proceed as follows: 1. Position the cursor on the first line 2. Then press the ENTER. button. The following screen appears: A: e+1 B: e+0 C: e-1 D: e-3 You can now view the factors of the TC parameters for the zero point, and change them if necessary. A5E , 03/2012 9

10 Temperature compensation of sensitivity To do this, proceed as follows: 1. Select the menu screen 'TC parameter input' (see above). 2. Position the cursor on the second line 3. Then press the ENTER. button. The following screen appears: A: e+0 B: e-1 C: e-3 D: e-5 You can now view the factors of the TC parameters for the sensitivity, and change them if necessary. Adjusting the zero point You can use this function to re-adjust the zero point of the H2S sensor. You can use nitrogen or air containing no H2S as the zero gas. To do this, navigate as follows: Calibration -> Please enter code -> Calibrate probe -> Choose component -> H2S -> Calibrate Zero Point. The following screen appears: H2S Zero cal. 3.3 vpm H 2S Nitrogen flow please Calibrate with ENTER Selecting this function switches from the sample gas inlet (inlet 1) to the zero gas inlet (Input 3). Now perform the zero point calibration as follows: 1. Wait until the displayed value has stabilized. 2. Begin the correction of the calibration by pressing the ENTER key. 3. End the calibration by pressing the ESC key. If an error is detected during the calibration, error number 29 is displayed (zero point of H2S sensor outside tolerance limits). 10 A5E , 03/2012

11 Calibrating the measuring range Span calibration You can calibrate the sensitivity of the sensor using this function. To do this, proceed as follows: MR Cal. Set span gas value Start Cal. MR Position the cursor on the 3rd line (Start Cal.) of the screen. 2. Press the ENTER key. The following screen appears: Set sp.: 50 vpm Reading: 47 vpm Connect span gas 3. Connect the sample gas inlet to the calibration gas. 4. Inject calibration gas with a flow rate of l/min. 5. Wait until the measured value has stabilized. 6. Then press the ENTER key. 7. You can end the calibration by pressing the ESC key. If an error is detected during the calibration, error number 30 is displayed (sensitivity of H2S sensor too low). Defining the installation You have to re-enter the date of installation after installing a new sensor. Prior to entering the date, you have to perform a zero point and measuring range calibration of the H2S sensor, otherwise the new date will not be accepted. The following screen appears when you select the 'Installation date' command: H2S Cal after inst. Date :11/05/2011 Now you can enter the date of installation in the form: 'DD.MM.YYYY'. A5E , 03/

12 Drift values You can use this function to display the drift values of the zero point and sensitivity (MR 1 and MR 2) and to reset them to zero. To do this, navigate as follows: Calibration -> Please enter code -> AUTOCAL/Drift values-> Drift values. The following screen appears: Thermo-AUTOCAL: OFF Drift values Cycle time AUTOCAL Purge time Position the cursor on line 2 (Drift values) and press the ENTER key. The following screen appears: Choose component : IR 1 Keep pressing one of the arrow keys until the 'H2S' component appears in the screen. Then press ENTER. The following screen appears: Drift H2S vpm Zeropoint: 0 MR1/2: 0 Reset driftvalues You can now view and reset the drift values. To perform a reset, position the cursor on the 4th line of the screen and press the ENTER key. Parameter control functions General information You can switch the sensor protection for the H2S sensor on and off using a menu. The standard setting is 'ON'. To do this, navigate in the operator menu as follows: Parameters -> Please enter code -> Limit values -> Choose component -> H2S. The following screen appears: Protec. sensor H2S: ON Limit values This function is described in detail in the standard operating instructions C79000-G52xx-C216-03, section In the normal case, each measured component is assigned two limits which can be set using this menu. No limits can be set for the measured component H2S. In this case, the function is used to switch the sensor protection on and off. 12 A5E , 03/2012

13 Protection and purging function of H2S probes (display in the operating screen: 'Protection Probe H2S') Hydrogen sulfide (H2S) is a corrosive gas, especially in wet condition and in combination with other gases. A protection and purging function has been implemented since H2S concentrations above the specified continuous concentration impair the functionality and service life of the H2S probes (50 vpm and vpm). A purging function has additionally been integrated for the 50 vpm probe, enabling a discontinuous measurement above its permissible continuous concentration. Probe protection function Definition of protection function of the two probes A value 1.1 times the specified range can be considered as the maximum continuous concentration. Although a measurement above such a concentration is still correct, the probe is damaged by longer exposure (several hours). The maximum continuous concentration remains constant even when changing the large measuring range. The function test is set during execution of the protection function in order to signal that the displayed value is incorrect. The protection function is also implemented with the 50 vpm probe for compatibility reasons even though its maximum continuous concentration is below its largest measuring range. Execution is the same as with the vpm probe. How the protection function works The protection function is triggered if the continuous measured value of H2S is greater than the maximum continuous concentration (110 % of full scale) in measuring mode for a period equal to the sample gas purge time. The following occurs when the protection function starts: The H2S measured value display is set to "*****" A "H" (H2S protection function running) is displayed in the measurement screen at the right edge where the test letter "!" appears (fault no longer pending logged). The zero gas value is opened The "Function test" status is set. As long as the protection function is active, the zero gas valve remains open during the zero gas purge time. The device then switches to the sample gas path. This process is repeated if the maximum continuous concentration is exceeded within the sample gas purge time. if the maximum continuous concentration is not exceeded again, the protection state is ended and the H2S measured value is displayed again, the function test and the test letter "H" are deleted. This process is repeated up to 6 times. If the sample gas concentration is too high after the 6th occurrence, the zero gas valve remains continually open and the fault message 28 (measured value channel 3 beyond tolerances). Return to measuring mode An active protection function can be interrupted as follows: A value is reached below the maximum continuous concentration during the purge time prior to completion of the 6th cycle Set the protection function to 'OFF' by changing the parameter in the limit display or via ELAN Start a different state such as calibrate, AUTOCAL, etc. Acknowledge fault 28 (measured value of channel 3 outside tolerance) in the logbook Note The analyzer continues to measure the gas concentration during execution of the sensor protection function. You can read via ELAN (k3, k19) or PROFIBUS whether the analyzer is being processed, and in which step. A5E , 03/

14 Sequence parameters The zero gas purge time is twice the AUTOCAL purge time. The sample gas purge time is equal to the AUTOCAL purge time. The AUTOCAL purge time is an adjustable parameter; its setting is described in the operating instructions, C G52xx-C216, section The protection function can be enabled and disabled with the menu command 'Protection Probe H2S' (see illustration above). The function is ON with the factory setting. An active protection function can be interrupted as follows: Set the protection function to OFF in the operator menu Set the protection function to OFF via ELAN Start another device state such as Calibration (e.g. AUTOCAL), Warm-up Acknowledge fault 3 in the log (menu command sequence: Diagnostics -> Analyzer status -> Logbook/Faults) The device remains in measuring mode while the protection function is running. The following illustration show how the protection function runs over time: Concentration Following 6 cycles Function test Zero gas valve open Zero gas valve closed MW > Limit 1 * ASZ NG purging 2 * ASZ Test time 1 * ASZ NG purging 2 * ASZ Test time 1 * ASZ 110 % MBE ASZ = Autocal purge time (for H2S usually: 5 min) MBE = full-scale value MW = measured value NG = zero gas t Figure 4 The H2S protection function over time 14 A5E , 03/2012

15 Probe purging function Definition of purging function of 50 vpm probe The maximum continuous concentration is 12.5 vpm. Although a measurement above such a concentration is still correct, the probe is damaged by an exposure of more than 10 minutes. Therefore measurements above 12.5 vpm must be carried out discontinuously and alternately with purging gas. The probe can be used for a measurement again following a purging time of equal duration with air. The function test is set during execution of the purging function in order to signal that the displayed value is incorrect. How the purging function works The purging function is triggered if the continuous measured value of H2S is greater than the maximum continuous concentration (12.5 vpm) in measuring mode for a period equal to the sample gas purge time. The following occurs when the protection function starts: The last measured value is 'frozen' if the 'Analog outputs with FCTRL' parameter has been set to 'Hold', or the current measured value is still displayed for all other settings. A "V" (H2S purging function running) is displayed flashing in the measurement screen at the right edge where the test letter "!" appears (fault no longer pending logged). The zero gas value is opened The "Function test" status is set. As long as the purging function is active, the zero gas valve remains open during the zero gas purge time. The device then switches to the sample gas path. The function test (FCTRL) remains set and the test letter "V" flashes during the zero gas purge time and the subsequent pre-purging phase. This signals that the displayed value is incorrect. The function test and test letter are deleted following the pre-purging phase, and the current measured value displayed again. Monitoring of the H2S limit is already re-activated during the pre-purging phase. Return to measuring mode An active purging function can be interrupted as follows: A value is reached below the maximum continuous concentration during the pre-purging phase Starting of the protection function Start a different state such as calibrate, AUTOCAL, etc. Note The analyzer continues to measure the gas concentration during execution of the purging function. You can read via ELAN (k19) or PROFIBUS whether the analyzer is being processed, and in which step. A5E , 03/

16 Sequence parameters The zero gas purge time is twice the AUTOCAL purge time. The pre-purging phase is equal to the AUTOCAL purge time. The AUTOCAL purge time is an adjustable parameter; its setting is described in the operating instructions, C79000-G52xx- C216, section The following illustration show how the protection function runs over time: Concentration Function test Zero gas valve open Zero gas valve closed MW > Limit 2 * ASZ NG purging 2 * ASZ Pre-purging 1 * ASZ MW > Limit 2 * ASZ 12.5 vpm ASZ = Autocal purge time (for H2S usually: 5 min.) MW = measured value NG = zero gas t Figure 5 The H2S purging function over time 16 A5E , 03/2012

17 Fault and maintenance requirements The faults and maintenance requirements of the H2S sensor for the most part correspond to those of the O2 sensor and are described in the 'Maintenance' section of the operating instructions C79000-G52xx-C The following faults and maintenance requirements are specific to the H2S sensor: Table 1 H2S specific fault messages No. Fault message/ Maintenance requirement Possible cause(s) S3 Measured value channel 3 (H2S) Sensor defective beyond tolerances Measured value display: ***** S14 Channel component error Sensor installed with incorrect measuring range Remedy Replace sensor Install sensor with correct measuring range S28 H2S protection function Sample gas concentration too high Check sample gas S29 Zero point of the H2S sensor Purge time too short for calibration Repeat calibration beyond tolerances S30 Sensitivity of the H2S sensor too Sensor depleted Replace sensor low W5 H2S sensor Measuring reserve almost depleted Replace sensor at the next opportunity Message S3 appears when the measuring capacity is depleted A5E , 03/

18 Replacing the sensor DANGER Danger of poisoning The replacement of the sensor module represents interference in the gas path. The sample gas circulating therein may contain toxic components that lead to death in certain concentrations. To ensure that the sample gas is free of toxic material when replacing the sensor module, the gas path must be flushed with ambient air or nitrogen for a period of about 10 minutes before performing the task. WARNING Danger of electric shock The device will be open when the sensor is being replaced. This means present dangerous contact voltage will be present, which can lead to electric shock. For this reason, the sensor module may only be replaced when power is off. WARNING Danger of chemical burns The H2S sensor contains sulfuric acid, which leads to burns on unprotected skin. Therefore do not use any tools when replacing the sensor module which could damage the sensor due to sharp edges or squeezing. If contact with the acid occurs nevertheless, rinse the affected skin immediately with plenty of water! CAUTION Hazardous waste The spent or defective H2S sensor is hazardous waste and must be packaged and disposed of accordingly! The spent H2S sensor is categorized as electronic waste with code number , "Hazardous component removed from discarded equipment". It must therefore be disposed of correctly and in an environmentally-friendly manner by a local waste disposal company. Environmental damage may occur if this stipulation is not followed. The polluter is also threatened with criminal action! Note The H2S sensor only has a limited service life depending on the operating mode and is therefore excluded from the analyzer guarantee. 18 A5E , 03/2012

19 Proceed as follows to remove the old sensor: 1. Flush the gas path for about 10 minutes with zero gas (AUTOCAL) 2. When sample gas is no longer present in the gas path, disconnect the analyzer from the power supply. 3. Open the unit by removing the four bolts on the cover. 4. Remove the connector from the H2S sensor (arrow). 5. Unscrew the H2S sensor out of the holder. Figure 6 Position of the H2S sensor in the analyzer (arrow) A5E , 03/

20 Proceed as follows to install the new sensor: 1. Tighten the new H2S sensor by hand in the holder up to the mechanical limit (shaded) Figure 7 Sensor holder (shaded) 2. Plug the cable with the connector onto the sensor. 3. Close the analyzer by screwing tight the cover. 4. Switch the analyzer on and wait for the warming-up phase. 5. Check for leaks in the device This is described in the standard operating instructions C79000-G52xx-C in section Preparations for Commissioning 6. Calibrate the H2S sensor as described in the section 'Calibration of the H2S sensor'. 7. Enter the installation date with the menu command "H2S Installation date". The analyzer is then ready for use again. Replacement parts The hydrogen sulfide sensor can be ordered as replacement parts as follows: H2S sensor with measuring range vpm H2S sensor with measuring range vpm A5E A5E A5E , 03/2012

21 Appendix TüV Expert's Report A5E , 03/

22 Siemens AG Industry Sector Postfach NÜRNBERG 22 A5E , 03/2012 A5E , 03/2012