Trusted
Proven
Effective
proven technology
Zirconium Oxide technology has been used for over 50 years in combustion processes. Though the science is settled, packaging concepts have evolved overtime. Zirtek Analyzers has built on fundamentals that initially endured in the high temperature, harsh atmosphere of the glass industry. The changes have been small, but important, to successful application in incinerators, kilns, thermal oxidizers, coking units, as well as
recovery units for both sulfur and bromine. Once you have prepared to do the "dirties", boilers, heaters and furnaces are easy.
The Zirtek Analyzers' approach is to keep it simple so it will survive longer with little or no attention. The in-situ design, heating the cell with the process gas, and sensing cell voltage, not current, eliminates the need for heaters, filters, aspirators, calibration, etc. Site preparation can be as simple as a mounting fitting, a small flow of metered reference air and a four conductor signal cable.
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advanced design
The ZKA Series Analyzer is the third generation since Zirtek Analyzers entered the market in 1989. The heart of the analyzer is a proprietary board designed and man-ufactured here in the USA using cutting edge technology. The design combines
the stability of analog signals, for control, with the flexibility of serial communications to provide the user with installation variations that fit site requirements. The analyzer electronics can be nearby the probe or a 1000+ feet away, connected by a standard 4 conductor (twisted pair, copper-copper) with an overall shield, instrument cable.
The Display Module (DM) is a graphic HMI featuring a touchscreen, serial com-munications, IP address, trending,histor-ical data logging and remote operation via VNC. One DM can function as the interface to multiple probes. Each probe has a dedicated control board that is linked to the DM via an RS422 daisy chain.
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Cost effective combustion control begins with oxygen measurement. Fast, reliable feedback of the actual excess oxygen concentration to trim an air/fuel ratio control loop can ensure safe, stable operation while keeping the fired process in its sweet spot. Why install more expensive, higher maintenance devices for control based on carbon monoxide (CO) when CO can already be accounted for as a combustible in the oxygen measurement?
Whether your priority is lower fuel cost or lower emis-sions, you can achieve both with increased efficiency resulting from measuring excess oxygen in the radiant section of the fired process.
~ Less fuel means less cost.
~ Less fuel means less CO2 released
~ Less excess oxygen means less NOx formed
Is your fired process sub-stoichiometric?
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combustion measurement
In-Situ Analyzers
Accurate - Zirtek's in-situ analyzer operates in the 1200 - 2900 F temperature range, making it possible to place the probe in the radiant zone adjacent to the combustion envelope. This minimizes errors which arise from tramp air (leakage), process lag and sampling issues ensuring measurement accuracy and stability.
Safe - The analyzer configuration consists of two assemblies, an intrinsically safe probe and powered electronics. The design makes meeting hazard classifications simple and cost effective by allowing the powered equipment to be placed outside the hazardous area.
Reliable - No calibration of the analyzer is required as the cells are guaranteed not to drift more than one percent (1%) of signal value over the life of the probe and the cell temperature variations are continuously corrected in the conversion algorithm. The Zirtek analyzer design, which does not use cell heaters and/or loading currents, provides the most cost effective, maintenance free, combustion measurement available.
Oxygen Measurement
Combustibles Measurement
A key element in combustion efficiency analysis and control is the accurate measurement of excess oxygen.
Measurement by Zirconium Oxide based sensors is and has been the preferred technique for several years. Zirtek's ZKA Series analyzers incorporate proven technology and state of the art electronics to allow you to have the best available solution to combustion measurement. Expect more and get it with the wet measurement of excess oxygen in the radiant section of the combustion vessel.
Measurement in processes that operate from near
stoichiometric to true fuel rich combustion conditions at temperatures above 625 C are challenging.
Most analyzers, at the elevated temperatures, require sampling systems which are complex and require significant maintenance.
They still only provide inferred or empirical measurement of the actual combustion conditions.
Zirtek's in-situ approach, based on Zirconium Oxide, measures Oxygen Depletion (Odel). It is a simple, direct solution to
monitoring and control of zones
with combustible components .
The millivolt-level signals generated by the Zirconium Oxide cell and thermocouple are scanned by the high impedance, precision electronics Control Board (ZPERP-CB), where linearization and conversion to engineering units occurs. The input signals are used to calculate Volume Percent Oxygen using the Nernst Equation. The Oxygen and Temperature values are available as scaled, 4-20mA analog Outputs via terminations on the electronics board.
The Oxygen value, cell temperature and cell millivolt signal level are displayed on the HMI Home screen as shown above. The touchscreen Display Module (ZPAERP-DM) provides a user friendly analyzer interface for the operator. Click on the image above for more detail.
Zirconium Oxide cells generate voltage proportional to the diff-erence in the oxygen concentrations of the reference air and the combustion gas. As oxygen is depleted in the process atmos-phere, the generated signal increases in magnitude. This char-acteristic along with tolerance for high temperatures makes zirconium technology a great choice for measurement in the reducing zones of fired processes.
The analyzer hardware is the same as used for oxygen meas-urement but the cell signals are processed and presented to show the combustible nature of the gas. The values for Odel, Percent Combustibles, cell temperature and cell millivolt signal level are displayed on the HMI Home screen as shown above. Click on the image above for more detail.
Location, Location, Location . . .
For most combustion applications, the best available information is in the radiant zone near the flame front.
The characteristics of the In-situ method of measurement are preferable over designs using close-coupled, bypass or extraction configurations. The farther the sensor is from the point of interest, the more likely the measured value will be compromised. Zirtek's in-situ probe is designed to give the best available service for these applications.
The Probe . . .
In-situ measurement is a simple concept but can be difficult to implement in harsh, combustion conditions where dust, fly-ash, etc., can be prevalent. Zirtek's
probe design is based on materials and techniques that have emerged from long service in the industry.
The Cell . . .
The sensing element of Zirtek's probe is a cell manufactured from zirconium oxide substrate and platinum electrodes. The technology has been widely used for decades but implementation is key to the successful application in industrial processes.
The Package . . .
Standard probe lengths are 18, 24, 30, 36 and 42 inches. The threaded (MNPT) mounting fittings are either 1 or 1.5 inch pipe size depending on the choice of sheath material. Standard sheath offerings are silicon carbide, alumina and high temperature alloys. The cable requirement for connecting the probe to the analyzer electronics is typical instrument cable having 2 twisted pair (4 conductors, copper-copper) with an overall shield. The run length, with 18 gauge copper wire, can be in excess of 1000 feet. A small quantity of dry, clean, ambient air is needed for the reference gas. The probe operates in an environment with a temperature range of 1125F to 2900F and nominal atmospheric pressure. Elevated pressure can be accommodated if necessary. Click on the probe image for more detail.