A laser based sensor for in situ, real time measurement of dissolved gas: application to CO2 in water
Lead Research Organisation:
Science and Technology Facilities Council
Department Name: RAL Space
Abstract
We propose the development of an instrument concept anticipated to enable for the first time the measurement of gases dissolved in water in-situ, in real time, at good resolution and in a compact and deployable package.
Current measurement techniques for CO2 dissolved in water typically involve the equilibration of the amount of CO2 dissolved in water with that in a volume of gas, followed by an optical measurement of the CO2 in the gas; or equilibration with an electrolyte behind a semi-permeable membrane and a measurement of the acidity of the resulting liquid. Neither process is especially fast and the former is not suited to immersion in the ocean. Equilibration is a relatively slow process. Consequently it is difficult to measure oceanic CO2 profiles with high spatial or temporal resolution.
We propose to develop some innovative laser-based methods to monitor gases dissolved in liquids. The first application targeted is dissolved CO2 in ocean water. With the proposed approach, no equilibration is required and good precision should be achievable in real time (seconds or better). The measurement is in principle tolerant of fouling and should be insensitive to a number of major instrumental and environmental parameters. The main tasks on the project will include initial design and trade-offs of the laser sensors, assembly and initial characterization, development of modulation schemes and quantitative data processing, and final laboratory tests to validate the technology. A fully developed instrument would be compact, have moderate power requirements, be immersible to significant depths and should be compatible with ship inlets, CTD (conductivity, temperature and depth) rosette water samplers and other ocean profilers.
The proposed sensor would significantly contribute to the overall study of the Earth carbon cycle by enabling three dimensional measurements of CO2. More specific research areas include carbon chemistry and surface CO2 flux studies, CO2 exchange between marine biosphere and ocean, ocean CO2 circulation, and evaluation of CO2 seeps at ocean ridges and submarine volcanoes to understand deep carbon pathways to the oceans. Good spatial and temporal sampling, including at depth, are also potentially applicable to studies of small-scale or dynamic CO2 distributions, for validating CO2 sequestration experiments and for monitoring oil drilling operations.
While we will be demonsrating our technique on CO2, the sensor concepts are widely applicable to the sensing of any molecular species dissolved in liquids. As such other numerous applications would be unlocked such as applications to water quality studies, or industrial characterisation of liquid contamination.
Current measurement techniques for CO2 dissolved in water typically involve the equilibration of the amount of CO2 dissolved in water with that in a volume of gas, followed by an optical measurement of the CO2 in the gas; or equilibration with an electrolyte behind a semi-permeable membrane and a measurement of the acidity of the resulting liquid. Neither process is especially fast and the former is not suited to immersion in the ocean. Equilibration is a relatively slow process. Consequently it is difficult to measure oceanic CO2 profiles with high spatial or temporal resolution.
We propose to develop some innovative laser-based methods to monitor gases dissolved in liquids. The first application targeted is dissolved CO2 in ocean water. With the proposed approach, no equilibration is required and good precision should be achievable in real time (seconds or better). The measurement is in principle tolerant of fouling and should be insensitive to a number of major instrumental and environmental parameters. The main tasks on the project will include initial design and trade-offs of the laser sensors, assembly and initial characterization, development of modulation schemes and quantitative data processing, and final laboratory tests to validate the technology. A fully developed instrument would be compact, have moderate power requirements, be immersible to significant depths and should be compatible with ship inlets, CTD (conductivity, temperature and depth) rosette water samplers and other ocean profilers.
The proposed sensor would significantly contribute to the overall study of the Earth carbon cycle by enabling three dimensional measurements of CO2. More specific research areas include carbon chemistry and surface CO2 flux studies, CO2 exchange between marine biosphere and ocean, ocean CO2 circulation, and evaluation of CO2 seeps at ocean ridges and submarine volcanoes to understand deep carbon pathways to the oceans. Good spatial and temporal sampling, including at depth, are also potentially applicable to studies of small-scale or dynamic CO2 distributions, for validating CO2 sequestration experiments and for monitoring oil drilling operations.
While we will be demonsrating our technique on CO2, the sensor concepts are widely applicable to the sensing of any molecular species dissolved in liquids. As such other numerous applications would be unlocked such as applications to water quality studies, or industrial characterisation of liquid contamination.
Planned Impact
The proposed project aims to initiate technological development combining infrared tunable laser spectroscopy with attenuated total reflectance techniques to enable compact, real time, sensitive, in situ sensors for liquid analysis. A concept demonstration is proposed, which once matured, is anticipated to be a very versatile piece of instrumentation and, as such, will enable a large range of applications, users, and ultimately impacts.
1. Impact generated through in-situ, real time sensing of CO2 dissolved in water
Better understanding of global carbon cycle, and carbon exchanges between the different spheres part of the Earth system impact through a better knowledge of the global change implications. This will eventually help in assessing mitigation approaches, minimizing negative social and economic outcome of the change.
The proposed technology could play an important role in sub-sea carbon storage experiments and facilities. Sensitive dissolved CO2 sensors would allow detecting leak at a very early stage and mitigating chances of storage failure. Economic impact takes the form of saved costs, while the social one relates to less CO2 released in the atmosphere.
Oil and gas industries are also to benefit from the proposed technology which enables the monitoring of submarine drilling operations. This area would offer economic impact in the form of business opportunity and potentially help in mitigate drilling failures that negatively impact the environment.
2.Impact generated by the generic technology proposed
The concept is generic and applicable to other chemicals dissolved in liquids.
Environmental applications within the remits of the environmental agency include the quantification of pollutants dissolved in water and the associated availability of sensitive water quality sensors. This would help rivers and ocean pollution assessment to the benefit of the population. It will facilitate regulation enforcement and therefore drive a better quality of waters, as well as facilitate the collection of scientific evidences for policy.
Industries would benefits through the possibility to implement sensors for in line process control of liquids.
The proposed system is also relevant to the detection of harmful threat chemicals that can possibly be mixed in water networks. This is relevant to civil security and would help to protect the population from threats and health hazards.
Lastly, the potential applications mentioned above indicate a business needs. The IP and the know-how developed during the proposed project would be exploited. This could be in the form of innovative spin off company delivering liquid sensor products and/or through licensing the technology. In any case, this benefits to the UK plc in the form of business creation (high value jobs) and associated wealth. It would also position the UK at the front in the field of innovative mid infrared laser based sensors through increase R&D in this area, which is a fast growing market. Social impact will be achieved through : job creation if in the long term the technology is exploited, the favouring of a better environment, and development of the skills set of the UK workforce in the field of experimental laser sensing science and engineering.
1. Impact generated through in-situ, real time sensing of CO2 dissolved in water
Better understanding of global carbon cycle, and carbon exchanges between the different spheres part of the Earth system impact through a better knowledge of the global change implications. This will eventually help in assessing mitigation approaches, minimizing negative social and economic outcome of the change.
The proposed technology could play an important role in sub-sea carbon storage experiments and facilities. Sensitive dissolved CO2 sensors would allow detecting leak at a very early stage and mitigating chances of storage failure. Economic impact takes the form of saved costs, while the social one relates to less CO2 released in the atmosphere.
Oil and gas industries are also to benefit from the proposed technology which enables the monitoring of submarine drilling operations. This area would offer economic impact in the form of business opportunity and potentially help in mitigate drilling failures that negatively impact the environment.
2.Impact generated by the generic technology proposed
The concept is generic and applicable to other chemicals dissolved in liquids.
Environmental applications within the remits of the environmental agency include the quantification of pollutants dissolved in water and the associated availability of sensitive water quality sensors. This would help rivers and ocean pollution assessment to the benefit of the population. It will facilitate regulation enforcement and therefore drive a better quality of waters, as well as facilitate the collection of scientific evidences for policy.
Industries would benefits through the possibility to implement sensors for in line process control of liquids.
The proposed system is also relevant to the detection of harmful threat chemicals that can possibly be mixed in water networks. This is relevant to civil security and would help to protect the population from threats and health hazards.
Lastly, the potential applications mentioned above indicate a business needs. The IP and the know-how developed during the proposed project would be exploited. This could be in the form of innovative spin off company delivering liquid sensor products and/or through licensing the technology. In any case, this benefits to the UK plc in the form of business creation (high value jobs) and associated wealth. It would also position the UK at the front in the field of innovative mid infrared laser based sensors through increase R&D in this area, which is a fast growing market. Social impact will be achieved through : job creation if in the long term the technology is exploited, the favouring of a better environment, and development of the skills set of the UK workforce in the field of experimental laser sensing science and engineering.
| Description | We have demonstrated that we can measure the amount of CO2 dissolved in water by measuring its optical properties. We are particularly interested in monitoring the amount of CO2 dissolved in the oceans, but our technique has wide applicability to the measurement of dissolved CO2 and other chemicals in other situations, for instance chemical processes, particularly where fast, non-intrusive measurements are needed. |
| Exploitation Route | The basic technique is relevant to: a) Study of the carbon cycle, including CO2 capture in the oceans b) Monitoring of CO2 as a tracer for oil well leaks c) Study and monitoring of CO2 sequestration in the deep ocean d) Non-intrusinve monitoring of CO2 and other dissolved chemicals with suitable spectral signatures in industrial and other processes (e.g. bottled drinks) |
| Sectors | Chemicals,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |