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Gas measurements Dilute - Non-Condensable Gases, DNCG
What is normally called dilute non-condensable gases, DNCG contains a mixture of different sulphur-containing substances; hydrogen sulphide, methyl mercaptan, DMS and DMDS.
The need to collect and destroy so‑called particulate matter (DNCG) has increased as the EU has tightened requirements for industry to use the best available technology to reduce sulphur emissions to air.
Some common sources of gas emissions in industrial processes include:
Combustion:
The combustion of fuels such as coal, oil or natural gas can result in emissions of carbon dioxide (CO₂), nitrogen oxides (NOₓ), sulphur dioxide (SO₂) and other pollutants, depending on the combustion process and the quality of the fuel.
Industrial processes:
Many industrial processes generate gases as by‑products of chemical reactions or material handling. These may include greenhouse gases such as methane (CH₄), as well as industrial pollutants such as ammonia (NH₃) and hydrogen cyanide (HCN).
Waste management:
Emissions from waste treatment, including landfill sites and wastewater treatment plants, may include landfill gases such as methane and carbon dioxide, as well as other hazardous chemicals released during the decomposition of organic material.
DNCG – Total Reduced Sulphur Amount:
The total of the reduced sulphurous odorous compounds formed during pulp production: hydrogen sulphide, methyl mercaptan, dimethyl sulphide and dimethyl disulphide, expressed as sulphur.
Diluted non‑condensable odorous gases:
Gases containing DNCG that are not strongly odorous (e.g., gases from tanks, washing filters, chip bins, lime mud filters or dryers).
Measuring weak gases at mills
Portable Gas Chromatograph
RISE has methods for measuring flow rates and analysing the sulphur content (TRS) in the pulp mills dilute non-condensable gases, DNGC. The concept is since a portable gas chromatograph is set up in place, so that the weak gases from different test points can be quickly analysed.
Do your own measurment with sampling kit
There is now also an option where RISE sends a complete sampling kit directly to you. You carry out the sampling on site, following our clear instructions. Once the sample has been taken, it can be easily returned to our laboratory using the enclosed return materials.
What is usually called dilute non-condensable gases, DNCG, or TRS gases contains a mixture of different sulphur-containing substances such as hydrogen sulphide, methyl mercaptan, DMS and DMDS. The method for pulp mills to solve the problem with odorous gases to pull the different emissions together and collect them to a point, such as the soda boiler, for combustion. But to be able to dimension a plant for this, the size of the flows and their composition must be known and mapped.
Since there is a wider deadline when new emission conditions apply to sulphur, we see here a need that we solve for our customers. Although the use has environmental permits that go beyond the time limit set by the EU, the sulphur condition will be renegotiated and, in many ways, the need may be to have the flows measured and analysed.
Analyses of gases in ventes from tanks and from landfill gas
RISE has methods for analysing the content of methane and other gases in ventes from landfills. The concept is based on the setting up of a portable gas chromatograph in place, so that the samples can be quickly taken and analysed.
Landfill gas is a mixture of gases produced when organic waste decomposes in landfills or rubbish dumps. Landfill gases mainly consist of methane (CH4) and carbon dioxide (CO2) but can also contain small amounts of other gases such as hydrogen cyanide (HCN), ammonia (NH3), and hydrogen sulphide (H2S). Methane is particularly concerning as it is a potent greenhouse gas with a much higher global warming potential than carbon dioxide.
Landfill gases can pose a significant environmental and health risk if released into the atmosphere without control. To mitigate this risk, landfill gases are typically collected through gas collection systems and either burned for energy production or converted into other useful products. This process, known as landfill gas collection and energy recovery (LFGTE), helps reduce greenhouse gas emissions while also generating renewable energy.
