Purity Meets Innovation!

Biological residual material is important as a renewable plant resource. Its full exploitation is therefore a key element in a bio-based economy. Biological residual materials cannot simply be accepted commercially if they release volatile organic compounds, also these processes must meet governmental standards with regard to their possible odor nuisance and gas emissions.

Its usefulness as an alternative raw material may suffer from the various chemical components present and the aforementioned odor nuisance. Biological residues typically develop a sulfurous odor in varying intensities, in some cases ammonia, polycyclic aromatic hydrocarbons, black carbon and sometimes particulate matter. In addition, regulatory authorities have committed to reducing unhealthy air pollution from volatile organic compounds (VOCs).

Various products are used as raw materials, including:

1. Biomass, from which starch (is basically sugar) in the corn or grains can be converted into alcohol.
2. Wood chips and bark are composed of three components: cellulose, hemicellulose, and lignin. Cellulose is a composite molecule of glucose; hemicellulose is a combination of glucose with other sugars and can be released from the wood and then converted to biofuel and biochar.
3. Vegetable oils, palm oil, oilseed rape that are converted into biofuel.
4. Manure can be used as green fuel like biogas and biomass when dried into pellets.
5. Algae contain numerous valuable components, such as oils, fatty acids, proteins, and sugar, so that they can be used to make biofuels, among other things.
6. VFG-waste is available worldwide and can be transformed into green gas as a replacement for natural gas by fermentation or gasification.

However, there are numerous actions that can cause an odor nuisance prior to the switch to biofuel. This includes drying biomass before it is further processed, chemical processes in which biomass is used, pumping liquid biomass into trucks, and then pumping it to ships for shipping and ultimately to storage tanks.

This removes gases that can spread quite noxious odors into the environment. The released gases must therefore be removed via a cleaning system before they can be emitted.

To prevent exceeding the allowed maximum odour emissions it has been decided to install odor control units (OCU) to treat the vapors emitted from tanks. The OCU will treat all vapors emitted by unloading products, internal transfers, and vapors emitted by heating up tanks.

Ravebo open spray scrubbers operate based on the difference in velocity potential between liquid droplets and the incoming gas. The liquid is discharged with moderate pressure through nozzles with the objective of getting a homogeneous droplet distribution and an equal spray pattern. The droplet size is especially important since ultrafine droplets have a particularly large surface-to-volume ratio. The exceptionally fine droplets create a fine mist, which results in an efficient capture of particles. The spray absorbers operate relatively simply, are very maintenance-friendly, and have fairly low energy costs.

Due to the lack of random packing or a structural packing, the open spray absorbers have a minuscule pressure loss and are virtually insensitive to contamination, which normally causes a larger pressure difference. The scrubber works according to a closed-loop pump system in which the washing liquid is pumped from the buffer. Based on measurement values from the gas analyzer.

The spray system consists of multiple removable spray lances with spray nozzles, some of which are co-current and some of which are counter-current. The positioning of these spray nozzles in the scrubber is of the utmost importance for optimal gas treatment because they capture particles because of the intensive contact between the washing fluid and the process gas. The clogging-free special configurated nozzles create fine droplets with a homogeneous spray pattern to capture as many dust and gas particles as possible. Optimal contact of fine liquid droplets with gases and dust particles will lead to a high absorption of polluting particles and gases.

The European Directive for Odor Concentration is obvious when it comes to determining odor emission. However, some components can also be measured with the appropriate gas analyzer. This is not a substitute for the European Directive but can be used as a tool to control the wet gas scrubber. On many occasions, wet gas scrubbers are controlled by using liquid sensors to measure the quality of the washing liquid. This is, however, an indirect way of measuring and is not always precise. High-end analyzers are fast-responding and, above all, very accurate, making them very suitable to measure the discharge of the scrubber system. As a result of this, the washing liquid can be controlled very precisely.