AquaGas Pty Ltd – Enews November 2016

We are delighted to announce the recent acquisition of several major projects in the field of Continuous Emissions Monitoring (CEMS) and industrial process control.

prony_energie

Continuous Emission Monitoring System

Prony Power Station in New Caledonia

AquaGas Pty Ltd, has been awarded a major contract for the supply, integration, installation and commissioning of two complete CEMS (Continuous Emission Monitoring System) used for compliance stack emissions monitoring of Prony Power Station located at one of the largest mining facilities located in southern hemisphere.

In this project, AquaGas has selected the LaserCEM (AP2E) and DR-320 R (DURAG) as the most suited technologies with regards to the application requirements and harsh monitoring conditions, providing the plant operator ENERCAL with the last generation of CEMS multigas analyser and dust monitors for online analysis of Particulates, HCl, SO2, NO, NO2, CO, CO2 and O2 at their two coal fired boiler facilities.

AquaGas scope also includes CDAS, Mcerts certified and state of the art data acquisition and reporting software suite. The CDAS software package ensures strict emissions reporting and clear environmental compliance.

The strong partnership with AP2E, expert in Laser Spectroscopy, and DURAG specialised in the field of environmental monitoring and process control has led to this first shared success, the acquisition of a capital reference for the LaserCEM in the field of power generation while enforcing AquaGas position in Oceania.

Prony Power Station is located on VALE mining site providing access to large port facilities for the supply of combustible. It consists of two 55 MW Alstom boilers (203 t/h – 87 bars – 515°C) equipped with Alstom turbines (85 bars – 500°C) and alternators (59 MVA – 11 kV) providing power for both the public demand and the needs of the large Nickel mining facilities.

Located close to the site and focused on customer satisfaction, AquaGas has implemented an efficient transfer of knowledge to the plant owner as well as to the local company ROBICAL assigned for the CEMS routine maintenance.

bn-hp826_0327ch_j_20150327044108

Continuous Emission Monitoring System

Caltex Lytton refinery in Australia

Caltex has recently approached AquaGas to perform a system expertise at their Lytton refining facilities near Brisbane.

The difficulties experienced by Caltex with their CEMS (Continuous Emission Monitoring System) had been related to the existing sampling method and resulted in a high maintenance level and unreliable monitoring operations.

Thanks to the customer feedback and following a couple of site visits, AquaGas has identified several ways to optimise the existing CEMS (Continuous Emission Monitoring System) sampling method. In order to secure the data availability and keep the maintenance requirements to their minimum, AquaGas Pty Ltd has supplied, integrated and installed a set of heated gas sampling probes:

  • ASP300

    At the boiler facilities, the ASP300 fitted with automatic blowback, calibration port in accordance with CEMS standards and a continuous soot removal system.

  • ASP400

    For the Thermal Oxidiser, the ASP400 equipped with automatic blowback, calibration port in accordance with CEMS standards and designed to handle high dust load as well as elevated process gas temperatures.

Both the ASP300 and ASP400 provide the plant operator with application specific features and innovative design resulting in a series of advantages:

  • Programmable back-flush sequences,
  • Calibration as per CEMS code,
  • Extended filtration surface,
  • Flue gas temperature measurement
  • Insitu filters – The ASP’s allows the inspection of the Insitu or “top filter” without the need for dismounting the probe (No fitters required for inspection or maintenance).
  • Adjustable temperature set point (set at 190 degree Celsius)
  • Continuous and automated soot removal performed directly at the sampling point

For further information on Ankersmid Gas Sampling probes, you can visit our website: www.aquagas.com.au.

Ankersmid Sampling

  • Universal

    CEMS integration made easy

  • Performant

    Field proven, high quality, durable Ankersmid Sampling BVBA patented designs

  • Modular

    Comprehensive range of gas sampling equipment from one source

  • Efficient

    Easy to install, maintain and operate

AquaGas is supporting the global industrial community with high performance environmental and process monitoring systems (Continuous Emissions Monitoring Systems, Air Quality Monitoring Systems, Online process analysers, Water Quality Monitoring Systems) specifically designed and built to meet your application requirements.

Indoor air quality

 

Air Quality in Submarines

The last generation of conventional submarines allows several weeks of submersion, creating a need for regenerative air purification methods and new air monitoring instruments. Submarine air is a complex mixture of compounds, where the most obvious contaminant is metabolically produced carbon dioxide. Normal eight-hour occupational exposure limits are not applicable on a submarine, instead special long-time exposure limits are set.

A number of air purification methods for submarines are either available or under development, e.g. cryogenic plants, biological plants and solid amine plants. For air monitoring, the OFCEAS method is an interesting option, already in use on-board nuclear submarines.

The main contaminant of submarine air is CO2. In ordinary buildings 1000 ppm is usually considered as a maximum concentration. This value is not based on health effects but on the rate of ventilation. In submarines, higher CO2 concentrations are permitted, usually 5000- 7000 ppm. A submarine atmosphere consists of a large number of contaminants such as ozone, which can be formed in electrical devices and hydrogen, which is formed when the batteries are charged.

To ensure the health of the crew on short and long term, it is important to specify the permitted composition of the submarine atmosphere.

ProCeasNAV-Onboard-air-quality-analyser

Table 1 shows a submarine air specification for a conventional submarine.

Compounds Limit Compounds Limit
NO2 5 ppm NH3 25 ppm
CO2 8 000 ppm O3 0.1 ppm
CO 35 ppm H2 2 %
SO2 2 ppm CL2 1 ppm
Formaldehyde 2 ppm H2O2 1 ppm
Akrolein 0.1 ppm

 

Since the crew is continuously exposed to the submarine air for several weeks, normal eight hour occupational exposure levels are not applicable and special exposure limits must be determined. Maximum Permissible Concentrations (MPC) are set for an exposure time of 90 days for a number of compounds likely to be found in a submarine. They have also set emergency MPC’s for 24 h and 60 min.

The ProCeas® NAV

The ProCeas® NAV is designed for online monitoring of CO2, CO, Freon, H2S, H2, O2, Formaldehyde (…) in nuclear and conventional submarines. The ProCeas® NAV uses the OFCEAS method commercialized by Ap2e of France.

ap2e-CEMS and Process Analysers

The OFCEAS system uses a high-finesse optical cavity to provide path lengths of tens of kilometres. Moreover the OFCEAS technology can also, in certain configurations, take advantage of broadband light sources to provide multi-component analysis, while offering improved sensitivity when compared with shorter path-length methods, such as Tunable Diode Laser absorption spectroscopy (TDLAS).

ProCeasNAV-indoor air quality in submarines

The ProCeas® NAV analyser has been designed to endure large temperature variations, high vibrations and englobes all criteria required by the military environment to assure long-term crew member health in a confined environment.

Some of the gases and measuring ranges available on the ProCeas® NAV are:

Carbon Monoxide CO: 0-1000 ppm – Lower Detection Limit: 1 ppm

Carbon Dioxyde CO2: 0-5% – Lower Detection Limit: 0.01 %

Hydrogen Sulfide H2S: 0-10 ppm – Lower Detection Limit: 0.1 ppm

Freon; R134a and R404: 0-1000 ppm – Lower Detection Limit: 2 ppm

Ethanol C3H6O 0-2000 ppm – Lower Detection Limit: 4 ppm

General characteristics

Response time < 10 sec

No Zero drift and no Span drift – No daily calibration required – No nitrogen, zero air, purge or other carrier gas.

Weight 15 to 20 kg

Dimensions 480 x 240 x 150 cm

Formaldehyde in Indoor Air

 

For continuous ambient and indoor air quality monitoring (real time at ppb levels), the ProCeas® spectrometer is equipped with a laser at a single wavelength used to determine the concentration of a specific compound with an extremely low detection limit and fast response time. The OFCEAS extended optical path and continuous signal feedback provide a high definition spectral response using what is essentially a traditional absorption measurement.

ProCeas

ProCeas® Formaldehyde at HUTCHINSON

As per the international OH&S regulations on Formaldehyde, Hutchinson, subsidiary of TOTAL, evaluated several technologies to implement continuous real-time monitoring of Formaldehyde at their Plant facilities.

The ProCeas® has been selected by Hutchinson as the technology the most suited to their monitoring needs in terms of response time, accuracy and flexibility around the integration within the mainstream of their installation.

Hutchinson uses the ProCeas® to measure various level of Formaldehyde in the air at 3 separated sampling locations: laboratory, offices & entrance hall.

ProCeas-INDOOR-AIR-QUALITY

ProCeas Key features

  • Low detection level
  • Complete pre-calibrated laser infra-red spectrometer
  • Reduced response-time with Low pressure sampling system
  • Suitable for a wide range of components in ambient air: NH3, O2, H2, H2S, HCFC, VOCs, (…)

Example of performances for the Formaldehyde

Measuring range: 0-10 ppm (up to 1%)

Lower detection limit: 1 ppb – (10 ppm at 1%)

Response time 2s

No Zero drift and no Span drift – No daily calibration required – No nitrogen, zero air, purge or other carrier gas.

Area Monitors for Sterilant Gas

Hazards of sterilant gases

Since sterilant gases are selected to destroy a wide range of biological life forms, any gas which is suitable for sterilisation will present a hazard to personnel exposed to it. The NIOSH Immediately Dangerous to Life and Health values (IDLH) for the three sterilant gases are 800 ppm, 75 ppm and 5 ppm for ethylene oxide, hydrogen peroxide and ozone respectively.

For comparison, the IDLH of cyanide gas (hydrogen cyanide) is 50 ppm. Thus exposure to even low levels of sterilant gas should not be treated casually and most facilities go to great lengths to adequately protect their employees. In addition sterilizers (as with any mechanical device) can and sometimes do fail and leaks have been reported. Continuous gas monitors are used as part of an overall safety program to provide a prompt alert to nearby workers in the event that there is a leak of the sterilant gas.Steri-Trac Area Monitors - sterilant gas - AquaGas

Monitoring Sterilant

The monitor alarms are typically set to warn if the concentrations exceed the OSHA permissible exposure limits (PELs), 1.0 ppm for ethylene oxide and 1.0 and 0.1 ppm for OH&S and ozone respectively. The PELs are calculated as 8 hour time weighted average values.

In addition to providing continuous monitoring, the better gas monitors include a computer based data acquisition system provides automatic data logging to assist with compliance with OSHA’s regulations and impending alarms that allow users to rectify problems before they become a hazard.

There are several technologies that are commonly used for the detection of sterilant gases, the main three being electrochemical, gas chromatography and metal oxide semiconductor. All three technologies are suitable for ethylene oxide, but only electrochemical sensors are used for hydrogen peroxide and ozone detection.

For ethylene oxide, metal oxide electrochemical sensors provide a low cost, long life detector offer very good sensitivity, fast alarm response times and small size. ChemDAQ gas monitor manufacturers mainly use electrochemical sensors for toxic gases because of their many advantages.

Electrochemical sensors have traditionally suffered from a cross sensitivity problems with other vapours (alcohols are especially troublesome in health care). Cross sensitivity results in false alarms, unnecessary evacuations and eventually a loss of confidence in the gas monitoring system.

AquaGas - ChemDag - Steri-trac

ChemDAQ has developed a proprietary chemical filter that allows the ethylene oxide to pass through but removes most common interferent gases and vapours (including carbon monoxide, ethanol and IPA). The use of this filter allow the ethylene oxide to be detected with all the advantages that electrochemical sensors have to offer, but without the problems of cross sensitivity.

Capture

 

AquaGas is supporting the global industrial community with high performance environmental and process monitoring systems (Continuous Emissions Monitoring Systems, Air Quality Monitoring Systems, Online process analysers, Water Quality Monitoring Systems) specifically designed and built to meet your application requirements.

Continuous IR laser spectroscopy

Applications and References

The ProCeas® and the LaserCEM® are based on the OFCEAS* measuring principle combined with a Low Pressure Sampling LPS (100 mbar absolute) developed and patented worldwide by AP2E (France), for the online analysis of several key gases in industrial, environmental and OH&S applications. It provides measurements with a very high spectral resolution in addition to an exclusive and powerful sampling method (no heated line nor treatment of samples) and an interference-free, fast and sensitive analysis, regardless of the matrix of the gas to be analysed.

 

Combustion cycle in refineries

oil-gas-industry_01

 

References: EXXON (optimising combustion in boilers), Fives PILLARD (optimisation tool for the production and the adjustment of burners for boilers).

With the environmental constraints, Oil companies are looking for optimum energy and environmental efficiency of their burners. Combined cycles boilers optimisation requires accurate simultaneous online monitoring of O2 and CO to ensure both compliance with standards and process control efficiency. The ProCeas, used to track real time the residual rate of O2 (less than 3%), ensures optimal combustion process automation. The accuracy of the measurement is a financial matter: according to the thermal performance of the burner, even a reduction of 0.1% of oxygen in excess represents millions of dollars of savings in the annual consumption of fuel.

CEMS in coal fired power station

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Reference: IBIDEN Power Station – Simultaneous SO2/SO3 monitoring at the catalyst outlet according to the oxygen content variation have been done with the ProCeas® analyser.

SOx monitoring

SO2/SO3: AP2E also intends to enhance the approach aimed at combining environmental compliance and process optimisation, even if this seems less obvious to understand at first sight. If today SO2 is correctly measured, this does not fully reflect the sulphur emissions from combustion units subject to this requirement. In the presence of oxygen, SO2 does in effect form sulphur trioxide (SO3), a gas that is much more corrosive than SO2.

LaserCEM

Other chemical phenomena occur, particularly in denitrification (DeNOx), which in the presence of ammonia may lead both to an over-consumption of ammonia and to filter blockages. Therefore, not measuring SO3 entails the under estimation of sulphur emissions, and also additional maintenance costs and over-consumption of reagents. To have continuous and precise knowledge of the SO2 / SO3 couple enables the operator to choose the controlling conditions for limiting the formation of SO3 and its indirect costs.

Biogas

biogas

References: SP Technical Research Institute of Sweden, Rhodia (France). VEOLIA for its Centre de Recherche Energie Environnement Déchet (CREED, Centre for research on energy, environment, and waste).

The processing of gases from biomass (biogas, bio-methane) remains a key step in industrial processes for producing various types of bio-energy, a manufacturing process that requires optimizing.

It is therefore imperative to have the ability to calculate the calorific value of these new gases and to be able to quantify the impurities present there, in order to reduce the risk of damage to facilities, to react quickly in case of malfunction, and to certify the quality of finished products. AP2E has installed several equipment units within the facilities of various players of the world of biogas around the world. The purpose is to analyse the CH4 and CO2 content, as well as the residual concentration of H2S. This is a major impurity which transforms into sulphuric acid in the presence of some moisture. It is a very corrosive acid; consequently it is destructive for the facilities and the engines that burn biogas or bio methane.

The ability to analyse in the same multiplexing equipment the H2S content (which varies according to the time of day) of the “raw biogas” at the exit of the casing serves to determine the use of this biogas and assess its composition and quality. Other compounds may also be monitored by adding specific laser sources, such as the water content, in order to control the efficiency of the condenser. AP2E is also currently studying the analysis of siloxane, another sore point for energy recovery.

Using a continuous analyser as a means of industrial control and economic optimization of production units is for the control of biogas quality. During the combined cycles of biogas generation, the absence of H2S is crucial. It is a major impurity and a source of engine breakage. However, conventional means of analysis have trouble distinguishing CH4 from H2S. Therefore, operators are forced to adopt an excessively prudent approach in the treatment stage with active carbon: it is changed even before it is totally saturated. With a continuous, accurate, and reliable analysis of the level of H2S in the exit of the adsorption bed, we can instead use it until its saturation point and reduce overall costs.

Tests conducted on a site with a valuation of 1 MW showed that the amortization of the analyser could be performed based on this single criterion of active coal consumption in less than a year. Indeed the cost of a monthly activated carbon charge is equivalent to AUD $65,000.

 

Indoor air quality

Fgas monitoring system

References: In 2010, AP2E won an important contract with the DCNS for air quality control equipment for the confined interiors of submarines (on-board crew safety).

In April 2015, European regulations included formaldehyde as a proven carcinogenic product (CMR). In 2014, the ProCeas was certified approved method by EXERA (measurement, control, and automation equipment) and the LNE (National laboratory of metrology and testing).

AP2E is already working in the confined air field (submarines) and is interested in the building sector.  This new classification impacts devices monitoring the exposure to workers or to the public of formaldehyde, Freon, Ethanol… present in the indoor air of industrial sites or sites hosting the public. The ProCeas® Formaldehyde continuously measures these changes with a minimum 10 ppm threshold (maximum 1%).

Food processing industry

The drying field is another good example of application where energy efficiency has to be kept in mind, especially when processing food powders. Water monitoring is useful for avoiding excessive energy consumption (adjust dryer load to obtain minimise the residual H2O content). Online monitoring of carbon monoxide (CO) answers safety concerns. When food powders are dehydrated, the conditions may be such that CO is generated in the dehydrator. Once conditions for generating CO are present, CO tends to increase its concentration very quickly. To keep the CO below potentially dangerous level, it is necessary to detect the first signs of CO which appear above the levels already present in the atmosphere. The ProCeas is actually in operation within ten drying towers in dry food production facilities and has been chosen as the most reliable monitoring equipment by companies leading food processing industry.

Engine emissions testing

The automobile engines sector also remains a major target. With the arrival of the new EURO VI standards since September 2014, manufacturers have been forced to measure many pollutants (NO, NO2, N2O, NH3, CO2, CH4, and ethanol).

ProCeas

Successful testing with ProCeas® was conducted around the world:

– NH3 at Renault and VOLVO (France)

– N2O at Volkswagen (Germany)

– NH3 at General Motors (USA)

– NH3, N2O, NO, NO2 at Sensor Inc. (USA)

In the USA with Sensors Inc. – (www.sensors-inc.com): in May 2012, AP2E signed a contract for supplying ProCeas® analysers for the real-time control of gas emissions of engine test benches in the automotive industry. Sensors Inc. is the leading American manufacturer of real-time testing equipment for gas emissions in the transportation industry. The new range of measuring instruments is marketed in the US under the name of SEMTECH LASAR and it consists of four modules (NH3, N2O, NO, and NO2), each capable of analysing three gases simultaneously.

Natural gas

To be used in the best conditions, so that it limits damage and maintenance of equipment, natural gas must be rid of impurities, especially hydrogen sulphide (H2S), which is very corrosive, and all traces of moisture. Current filtration systems run against, among other things, the problem of measuring residual traces of these impurities because no reliable continuous analysis system was available so far. Today the main players in the “Oil & Gas” market deem the ProCeas® as the most efficient natural gas analyser for continuously and simultaneously measuring traces of H2S (LoD under 50 ppb) and H2O (under 50 ppm), without interference, without any dependence vis-à-vis the constitution of the gas, and with response times under a few seconds

Pure Gas

Pure gases online analysis

 

The ProCeas® is used by pure gases manufacturers to control the purity of the gas along production line (N2, H2, O2…).

Syngas

ProCeas H2O CO O2

References: Total, CEA Grenoble, IFP (French Petroleum Institute), GDF Suez, VEOLIA (CREED), Arkema

H2O, CO, CO2, and H2 rates

Praxair uses the ProCeas® as an online analyser of H2O, CO, CO2, and H2 rates, in a process for producing syngas from the gasification of coal, oil residue, pet coke, and biomass. This syngas is then used either as a source of energy in a heat and electricity combined cycle process or in a Fischer Tropsch process for producing second-generation bio-fuel. This process requires that the residual H2S generated by gasification have a value of less than 1 ppm to avoid the destruction of the polymerization catalysts.

CO, CO2, H2O, CH4, H2S, NH3 and H2

Midrex is a steel manufacturer that uses a gasification process similar to Praxair’s in order to cogenerate the electricity and heat needed in the manufacture of its steel. AP2E delivered to Midrex complete solutions that have enabled it on the one hand to measure the calorific value of these synthetic gases (by measuring CO, CO2, H2O, CH4, and H2) and also the presence of impurities such as H2S and NH3.

H2, H2O and Cl2

Today, the ProCeas® provides what no other infra-red laser technique could: the direct measurement of hydrogen (H2) and water (H2O) in chlorine (Cl2) without reagents or discharges, and interference-free. The ProCeas® performs measurements with a very high spectral resolution of very low concentrations (under a few ppm), with response times under a few seconds. This analyser also provides a control of the drying (H2O) in a chemical process at Arkema.

*Optical Feedback Cavity Enhanced Absorption Spectroscopy: technology developed and patented by the University Joseph Fourier (France), coupled to a Low Pressure Sampling(100 mbar absolute) developed and patented worldwide by AP2E, for the on-line analysis of different gases. By the end of 2010, after two years of R & D studies, the AP2E ProCeas®was the award recipient of the USA “R & D 100” which rewards the 100 most innovative global technologies of the year.


AquaGas is supporting the global industrial community with high performance environmental and process monitoring systems (Continuous Emissions Monitoring Systems, Air Quality Monitoring Systems, Online process analysers, Water Quality Monitoring Systems) specifically designed and built to meet your application requirements.

OFCEAS & Low Pressure Sampling

Continuous Emissions Monitoring and Process Control

Starting in 2012, AP2E launched the industrialisation of the ProCeas® and LaserCEM® product range, the continuous and multigas analysers using OFCEAS* patented laser spectrometry. This analyser range is based on several innovations, providing very high performance in terms of response time (less than a few seconds) and great accuracy of the analyses (wide dynamic range from ppb to %):

OFCEAS, CONTINUOUS INFRA-RED LASER SPECTROSCOPY TECHNOLOGY

The ProCeas® and the LaserCEM® are based on the OFCEAS coupled to a Low Pressure Sampling LPS (100 mbar absolute) developed and patented worldwide by AP2E (France), for the online analysis of several key gases in industrial, environmental and OH&S applications. It provides measurements with a very high spectral resolution in addition to an analysis system with a simplified sampling (no heated line nor treatment of samples) and an interference-free, fast and sensitive analysis, regardless of the matrix of the gas to be analysed.

ProCeas

The OFCEAS technology essentially differs from the CRDS (Cavity Ring Down Spectroscopy or Spectroscopy by resonance damping time) technology by its feedback principle: a part of the emitted radiation is returned from the chamber to the laser, enabling the tuning of the laser and the cavity resulting a resonance phenomenon. With a volume of only 15 cm3, the measuring cavity or cell is equipped with mirrors whose reflectivity exceeds 99.99%, providing an optical path between 1 and 10 km (approx. 10 meters in conventional technologies). The immediate consequence of this phenomenon is the identification of very intense absorption peaks with a very narrow spectral width. Given that the source used is a continuous laser, the system presents very high measurement stability: there is no zero drift and no need for new calibrations.

LOW-PRESSURE SAMPLING SYSTEM

The Low Pressure Sampling (LPS) System allows reducing the sample dew point (vapour pressure) to prevent the risk of condensation. The sampling method is achieved by the use of a sonic nozzle which allows reducing the sampling pressure down to 100 mbar. In these conditions the ambient temperature is almost always above the dew point eliminating the risk of condensation.

r4

  • No Sample heated line required to eliminate condensation: low power consumption, no related ongoing maintenance
  • True Direct Extractive CEMS/Process analyser (no dryer or scrubber)
  • No risk of absorption/desorption typical of high SO2/SO3 application
  • Low pressure accentuate the gas finger print
  • Cost effective multipoint monitoring
  • Standard system comply with ATEX standards

The integrity of the sample is therefore ensured. The very low airflow ensures a verylow response time and a minimal contamination of the system.

OFCEAS Detection limits

All these points enable to both increase the detection sensitivity and  simultaneously reduce the noise, which permits the detection of gases at very low levels of sensitivity (traces of H2S – LOD under 50 ppb, or traces of H2O – under 1 ppm).

ProCeas

Complete pre-calibrated multicomponent (H2S, CO, CO2, H2, H2O, HCl, HCN, HF, N2O, NH3, O2 and CH4) laser Infrared Spectrometer designed for online monitoring of combustion process, natural gas (LNG), pure gas (trace) and ambient air (trace).

 

LaserCEM

The LaserCEM is a complete pre-calibrated multi-component (NO, NO2, NOx, SO2, CO, HCl, CO2, H2O, H2S, NH3, N2O, COS, SO3, CH4, HF) laser Infrared Spectrometer designed for Continuous Emissions Monitoring and compliant to standard EN 15267-3 : 2008 and QAL 1 de EN 14181 . With the announcement of the continuous measurement of SO3 (sulphur trioxide) at the exit of combustion units, AP2E represents the link from an industrial point of view between regulatory measurements (EMC) and optimizing production processes. If SO2 is now properly measured, it does not fully reflect the sulphur emissions from combustion units subject to this requirement. In the presence of oxygen, SO2 does in effect form sulphur trioxide (SO3), a gas that is much more corrosive than SO2. And other chemical phenomena occur, particularly in de-nitrification (DeNOx), which in the presence of ammonia may lead both to an over-consumption of ammonia and to filter blockages. Not measuring SO3 entails the under estimation of sulphur emissions, and also additional maintenance costs and over-consumption of reagents. To have continuous and precise knowledge of the SO2 / SO3 couple enables the operator to choose the controlling conditions for limiting the formation of SO3 and its indirect costs.

*Optical Feedback Cavity Enhanced Absorption Spectroscopy: technology developed and patented by the University Joseph Fourier (France), coupled to a Low Pressure Sampling (100 mbar absolute) developed and patented worldwide by AP2E, for the on-line analysis of different gases. By the end of 2010, after two years of R & D studies, the AP2E ProCeas® was the award recipient of the USA “R & D 100” which rewards the 100 most innovative global technologies of the year.

 


AquaGas is supporting the global industrial community with high performance environmental and process monitoring systems (Continuous Emissions Monitoring Systems, Air Quality Monitoring Systems, Online process analysers, Water Quality Monitoring Systems) specifically designed and built to meet your application requirements.

 

Process monitoring in biogas plants

Why is process monitoring necessary?

Biogas plants are biological systems involving various interacting micro-organisms that anaerobically degrade organic matter. The main product is biogas, a gas rich in methane (CH4) that can be used as a renewable fuel for vehicles or to generate heat or electricity for local use or for use via energy distribution grids.

The degradation involves four consecutive biological processes: hydrolysis, acidogenesis, acetogenesis and methanogenesis.

 

Wasistbiogas

If one of these processes is negatively affected in any way there is an immediate influence on the other processes and the biogas plant can become unstable. Typical process failures include, among others, organic overload, hydraulic overload and ammonia inhibition. Process monitoring can help to understand what happens in a biogas plant and help to maintain a stable process. In many cases, a strongly inhibited micro-organism population or a total crash of the whole plant can have severe financial consequences for the biogas plant operator.

In general, process monitoring in anaerobic or other fermentation processes can help to:

  • Give an overall picture of the biogas process
  • Identify upcoming instabilities in anaerobic digester before a crash happens
  • Accompany a successful start-up or re-start of a plant

The costs of online monitoring are often much lower than the costs and lost revenue associated with re-establishing a biologically destabilised plant.

For example, if a biogas plant has totally crashed it may have to be emptied and filled again with new inoculum. This, together with the necessary start-up period, means that several months can be lost during which the plant could have operated at full load. The financial consequences can be devastating for the plant operator.

Key parameters in Biogas monitoring

Biogas plant

In biotechnological processes, the detailed monitoring of the fermentation product, in this case biogas, provides valuable information. Therefore, it is recommended to monitor both the volume of gas produced and the gas composition. With regard to process monitoring, a change in either gas production or gas composition can be an indicator of process imbalance.

Biogas primary constituents

  • CH4 and H2S measured during the methanation process give a good overall view of the performance of the degradation process and bacterial activity. A decrease in methane content can be a first sign of organic overload, provided that the feedstock mix has not recently changed. Similarly, a sudden increase in H2S can provoke process instability.
  • Simultaneous real-time monitoring of CH4, H2S and CO2 empower process automation (i.e. operation of scrubbers)
  • Before entering the distribution chain, the product must be qualified, again for economic reasons (excess H2S and/or CO2 in the CH4 would make it ‘sour’ and potentially corrosive enough to damage distribution infrastructure)
  • CH4, H2S, CO, CO2 and O2 Continuous Stack Emissions Monitoring required for environmental compliance

 

PROCEAS

Stationary Biogas Monitoring Systemslogo-ap2e

In general, a large variety of devices can be applied for measuring biogas production but in practice, as biogas is of variable gas composition, dirty, corrosive, wet, and produced at low pressure, measuring biogas volume and composition accurately is one of the most challenging parameters at a biogas plant. In the long run not properly designed systems can pose considerable problems due to corrosion, fouling or general deterioration when measuring raw biogas.

AquaGas Pty Ltd introduces the OFCEAS technology and Proceas BioGas analyser  designed by AP2e to address the analytical (online monitoring of biogas primary constituents) and operational (zero drift, minimum maintenance, no consumable, autonomous operation) biogas plants and methanation process monitoring requirements.

AP2e ProCeas BioGas

 

The ProCeas BioGas analyser features two patented technologies:

  • The OFCEAS IR Laser technology for enhanced specificity, selectivity, accuracy and stability (no instrumental response drift.):  The OFCEAS is a self-referencing spectrometer. This means that there is no need to re-analyse a zero and/or a span gas on a regular basis. The “zero” information is contained in the direct measurement spectrum while the “span” information is intrinsic to the analyser (pre-calibrated with 4 OD linear response).

OFCEAS - ProCeas BioGas

  •  The Low Pressure Sampling (LPS) system enabling low-cost installation thank to non-heated lines and reduced maintenance. Lowering the pressure of a gas sample reduces the bandwidth of the absorbance bands. At atmospheric pressure, simultaneous measurement of H2S (ppm’s) in presence of CO2 (10’s %), CH4 (10’s %) can be tainted by cross response / false positive due to spectral overlapping of CO2 and CH4 bands with H2S  information.  If operating at 100 mbar, all absorption bands have narrowed down to the point where there is no spectral overlap of the absorption bands. Cross response have been eliminated. 

OFCEAS Detection limits

When sampling gas from landfill, anaerobic digestion/bacteria and other fermentation processes, the use of a dedicated sampling system is necessary to ensure a specific sample preparation and to preserve your monitoring equipment. Another advantage of the LPS System is the ability to reduce the sample dew point (vapour pressure) to prevent the risk of condensation. The sample extraction is achieved by the use of a sonic nozzle. The sample is taken at a very low pressure (50 to 200 mbar abs, 100mbar nominal). At 100 mbar abs. the ambient temperature is almost always above the dew point eliminating the risk of condensation.

LPS biogas sampling probe

  • No heated line required to eliminate condensation: low power consumption, no related ongoing maintenance
  • Sample does not need to be treated – True Direct Extractive CEMS and Process analyser
  • No risk of absorption/desorption

The ProCeas offers sampling solutions tailored to the needs of the biogas production industry with automated sampling sequences and multipoint monitoring enabling fast, accurate and detailed analysis at various location with a single instrument: Raw biogas (1), processed biomethane (2), vented biogas (3) and stack emissions (4).

 

AP2e ProCeas multistreams

 

The Proceas Biogas Monitoring System is a cost effective online monitoring solution offering application specific features including:

  • Field proven technologies in the Biogas production industry
  • Simultaneous measurement of all primary constituents of Biogas
  • Fully automated standalone system (automatic calibration and sampling sequences)
  • Low Pressure Sampling (no sample condensation)
  • Deep particulate filtration
  • PFA and PTFE gas path (essential to avoid loss of components of interest)
  • Fast, accurate and reliable online analysis
  • No drift or deviation therefore minimal calibration requirements
  • Low-maintenance and user friendly system
  • Site specific sampling solutions

ProCeas Layout

The ProCeas analysers are manufactured and pre-calibrated by AP2e in France. The systems are built, integrated and tested in Australia by AquaGas. Standard systems are delivered fully integrated in a 19 inch rack suitable for installation in industrial settings (indoor 15-35C). For installation in hazardous area the BioGas Monitoring System is available in ATEX certified version.


 

ABYSS

Portable Biogas Analyser

Ankersmid Sampling

 

Short term measurement during start up conditions

The start-up of a biogas plant is a very sensitive process. Due to slow multiplication of some of the micro-organisms involved in anaerobic sludge and the consequent risk of hydraulic overload, the start-up of a biogas plant can take much longer than in other biotechnological processes. A start-up time of 1-2 months is nothing exceptional in biogas plants.

Therefore, the effort in process monitoring has to be highest during start-up. If the start-up is too fast, a sub-optimal biogas process can be the consequence because the most favourable micro-organisms have not multiplied in the biogas plant. In contrast, a slow start-up can cause a possible loss of income as time is taken to reach full load capacity. The frequency of the measurements should be increased during this crucial process steps.

Poster Process Monitoring in Biogas Plants-v1

The  ANKERSMID Portable Biogas Analyser is especially designed so that detailed gas analysis can be carried out at any time in any place. The entire gas conditioning system is housed in a compact and robust carrying case which ensures that the components can be removed easily and gas analysis performed in an efficient manner: quickly, safely and with a  minimum maintenance. This system ensures reliable sample preparation without loss and prevents damage on the  analysis system used downstream.

portable emissions measurement system-probe

The ABYSS Portable Biogas Analyser uses a dual beam Infra-red cell highly resistant to corrosive flue gases and harsh environments of operation.  Its light weight rugged enclosure fitted LCD screen, safety filter and Quick Connect fittings enables efficient short term measurement of emissions and process gas in waste recycling facilities, industrial fermentation plants and associated odour filtration systems.


AquaGas is supporting the global industrial community with high performance environmental and process monitoring systems (Continuous Emissions Monitoring Systems, Air Quality Monitoring Systems, Online process analysers, Water Quality Monitoring Systems) specifically designed and built to meet your application requirements.