Emissions Monitoring FAQ's
- What is Krystallon Continuous Emissions Monitoring?
- What does Mid-IR mean and how does it work?
- What is a Mid IR spectrum?
- How is it better/different from other emission monitoring technologies?
- What is a QC Laser and how does it work?
- Which gases can the CT1000 marine system measure?
- What is CEM or CEMs?
- What are the detection range and resolution of the CT1000 Marine system?
- What is the typical CT1000 measuring performance?
- What calibration is required for the CT1000?
- What are the components of a CT1000 and how is it installed?
- What are the environmental operating constraints?
- What is the format of the output and is the data recorded?
- What types of data are stored and displayed?
- What stack diameters can the CT1000 accommodate?
- What Warranty do you provide?
- What are the power requirements of the CT1000?
- What maintenance and consumables does the CT1000 require?
- How long does it take to install and commission the CT1000?
- What does the pre-commissiong preparatory work consist of?
- What approvals does the CT1000 have?
1. What is Krystallon Continuous Emissions Monitoring?
The Krystallon CEMs consists of in-stack probes through which a highly tuned laser beam light source is projected, through a gas path of at least 2/3 the diameter of the stack. The light path is twice the length of the probe as a mirror at the outer end of the probe reflects the laser beam back to a detector. Light in the mid IR range that has not been absorbed by the exhaust gas passing through the probe is absorbed by the detector. The wave numbers and intensity of the received light is sent as an anologue signal to the CT1000 system processor. The signal is processed and converted into a digital output for onward transmission to a data recorder and is simultaneously displayed on the CT1000 data screen. The CT1000 enclosure also contains the quantum cascade laser diode. Laser light from the diode is transmitted by a switching system and individual high quality optical fibre to each probe in sequence. The rapid “firing” of the laser diode enables each probe to be measured several 10s or 100s of times a second before the switch transfers the laser beam to the next optical fibre and probe.
Mid-IR stands for Mid Infrared. In spectroscopy, IR radiation is passed through a sample of gaseous molecules. Some of this radiation is transmitted through while the rest is absorbed by the sample, producing an infrared spectrum, or “molecular fingerprint”. Because each molecular structure has a unique combination of atoms, each produces a unique infrared spectrum. From this, identification (Qualitative analysis) and analysis (Quantitative measurement) of the gas is possible.
A Mid infrared spectrum is a fraction of the sample transmission of infrared radiation as a function of wavelength. The infrared spectrum results from the interaction of infrared radiation with sample molecules. The wavenumber scale (x-axis) is used to present the spectrum, to achieve constant distances between the data points. As there exist no two chemicals that have the same Mid IR spectrum, that spectrum is often referred to as a "fingerprint" of a molecule.
Measuring gases in the mid IR region offers incomparable advantages over optical gas sensing in other spectral ranges or incumbent technologies (chemiluminescence, electrochemical).
In practice, most gases leave their strongest and unambiguous spectral signature in the Mid IR, over a range (3um to 20um) that can be reached by tuning quantum cascade lasers.
The main advantages can be listed as follows:
- Sensitivity: the Mid IR offers the capability to measure accurately trace gas concentrations of less than a part per billion.
- Selectivity: The risk of cross interference from contaminant species is minimal due to the very narrow band at which measurements are recorded.
- Dynamic Range: A linear response can be observed over orders of magnitude.
- Low maintenance: The instruments are solid state and do not require consumables
- Fast response: the technology can achieve thousands of measurements per second.
In addition, Infrared is a non destructive technique.
Quantum cascade lasers (QCLs) were first invented in 1994 at Bells Labs USA. The QCL is based on a fundamentally different principle to normal semiconductor lasers.
It operates like an electronic waterfall where Electrons cascade down a series of identical energy steps built into the semiconductor material during fabrication, emitting a photon at each step. This is unlike diode lasers which emit only one photon over the similar cycle.
This means that quantum cascade lasers can outperform diode lasers operating at the same wavelength by factors greater than 1000 in terms of power due to the cascading effect and the ability to carry large currents.
It can also be designed to emit at any wavelength over an extremely wide range using the same combination of materials in the active region.
The CT1000 marine system has been developed to measure: NO, NO2, SO2, CO2, H2O.
CEM stands for Continuous Emissions Monitoring and a CEMs is a Continuous Emissions Monitoring system.
The detection range is a parameter that can vary and be improved depending on customer’s needs and industry constraints. The resolution is down to 100s of ppb.
NO |
0-2 000 ppm |
CO2 |
0-100 000 ppm |
NO2 |
0-300 ppm |
SO2 |
0-1 000 ppm |
- Linearity deviation < 0.7% of the range
- Cross Sensitivity interference < 0.4% (comparing with 4% certification requisite)
- Drift < 2ppb
The instrument response with known determinand concentrations shows an excellent linear response (correlation coefficient r2 effectively equal to one) with a maximum deviation of 0.2%, 0.7% and 0.1% observed respectively for N2O/air, CH4/air and N2O/N2 compared to the MCERTS requirement of less than 2%.
In addition, for the ranges tested, the maximum effect observed for cross sensitivity due to interfering substances was only 0.4% for N2O and 0.3% for CH4, comparing favourably to a 4% MCERTS requirement.
Sensor drift was assessed by passing a fixed concentration of determinand gas (N2O) through the sensor for a period of 4 hours. The reading drift during that period was less that 2ppb. Finally the recorded spectral features for both N2O and CH4 were compared with theoretical predictions. RMS residuals were equivalent to less than 600 ppt in a 1 Hz bandwidth, providing strong evidence of the ultimate noise performance of the QCL gas sensor technology.
The CT1000 should require no calibration at installation or during its lifetime. The QCL lasers and electronics are very stable and the fundamental physics of the gas absorption spectra doesn’t change over time.
The CT 1000 system comprises a single multigas analyzer and a probe per stack with attached conduit. The conduit incorporates temperature control box for the heated probe. All power and control for the probe and temperature control box is provided via the conduit from the multigas analyzer.
The installation site must be free from risk of direct liquid spillage and away from any hot air vent. The CT1000 Multigas Analyser is designed to operate within a temperature range of 5 – 55°C and humidity 0 – 95% RH non-condensing. The sections of the probe outside the stack are designed to operate within a temperature range of 5 – 70°C and humidity 0 – 95% RH non-condensing.
The Krystallon CEMs is a fully comprehensive turnkey installation consisting of detector system, remote data display, and a tamperproof data recorder. The data display and the recorder are normally located in the Engine Control room. The system has the facility to output the data stream to other shipboard control and operating display systems if required and specified by the purchaser. The data recorder is a certified secure recording system and is capable of easy removal for separate inspection and data interogation. However historical data interogation can be carried out on board ship thorugh a simple menu system.
The system data consists of quantatative gas emissions in parts per million or a percentage by volume as appropriate for the gas concentration. The data is provided for each stack that is monitored and includes a time and date reference. Because the system is also linked to the ship’s GPS the Krystallon CEMs also includes a reference to ship’s position, speed and heading as well the time and date stamp. This means that the emissions from the ship can be determined for any time and date and also geographical location.
Stacks with diameters between 350mm and 2m can be monitored with the probes currently available for the CT1000. Stacks outside this size range can be monitored with a customised sampling method. In this case it is advisable to discuss your requirements with Cascade Technologies.
The Krystallon CEMs includes a 1 year warranty from commissioning. The system can be supplied with recommended spares which are simple plug-in replacements. Some components can be returned for repair on an exchange basis. The system is typically expected to operate for 20 years but some components such as the probe filters need periodic replacement, (dependant upon operating conditions every 6 to 12 months). An e-mail help desk will be available for operator enquiries.
The CT1000 is designed to operate from 110V or 220-240V A.C. The current rating for a 110V A.C. supply is 10A for the Multigas Analyser and 8A per probe. The current rating for a 240V A.C. supply is 5A for the Multigas Analyser and 4A per probe. The system will operate on either 50Hz or 60Hz.
The CT1000 is designed to be inherently maintenance and consumable free. The only components we recommend replacing are the filters within the probe on an annual or as required basis. This can be carried out by the ship’s engineering crew.
The CT1000 system installation should take around one day. Much of the preparatory work can be accomplished at sea by ship’ staff or contractors. Krystallon will provide a detailed project plan of pre-commissioning work required to be completed prior to final installation and commissioning. Krystallon’s authorised agents will survey each ship in the preparation of the pre-commissioning project plan. Krystallon can also provide authorised contractors to undertake the complete project at favourable rates.
- Installation of stack stabbings with mounting flanges
- Installation a small data switch box located close to the stack stabbings.
- The supply of data and power cables between typically the Engine Control Room and the Funnel area. If local power distribution is available then this can be utilised for the system power supply and the probe heaters. Data is normally transmitted by fibre optic ether net cable between the probes and the data processor located in the Engine Control room.
- Link to the ship’s GPS system to supply data to the data processing and data recording system in the Engine Control room.
- The installation of the Krsytallon CEMs data processing and recording cabinet in the Engine Control room. This cabinet is a standard universal marine instrument 19 inch cabinet and contains the data recorder, system processor, data screens, and support equipment such as uniterruptable power supply.
Krystallon can arrange the pre-commissioning installation at favourable rates, but will in all cases Krystallon will provide a detailed pre-commissioning project plan based upon a detailled ship survey by our auhtorised contractors.
The CT1000 has passed Mariner Industries marine equipment environment testing. It has been performanced tested at the United Kingdon National Physical Laboratories where it has exceeded all standards for on-line gas monitoring requirements.
The UK Adminstration, (the Maritime and Coastguard Agency, MCA), has inspected to its satisfaction the performance of suitability of the Krystallon CEMs system and has granted full approval for marine use including the application for montoring exhaust emissions under Method B of the IMO resolution MEPC.130(53), “Guidelines for on-board exhaust gas-SOx cleaning systems”.