16-07-2018

Five BHS-Sonthofen filter systems ensure efficient natural gas processing in Iran

BHS-Sonthofen has produced five filter systems for use in natural gas production in southwest Iran, together with its Iranian sales partner Faris International. Full turnkey systems that combine several process steps for processing amine, which is crucial to gas scrubbing, in one closed process were accepted at the end of April. The new plants allow for the environmentally friendly and efficient circulation of raw materials.

120,000 barrels of liquid natural gas (LNG) per day – This is the planned capacity of a new gas refinery in Iran that is currently being constructed unter the project name ‘Bid Boland II’. In the future, natural gas will be extracted from the earth and separated from contaminants in the first process step. BHS-Sonthofen supplied expertise in the clarifying filtration of process liquids as a specialist in filtration technology.

Optimizing the ‘amine sweetening’ process with BHS
Natural gas is extracted from the ground as a mixture of gases, and some of its components are not suitable for further processing. These include sour gases such as hydrogen sulfide and carbon dioxide. These contaminants can be washed out using the ‘amine sweetening’ process, an internationally licensed process developed by the French license provider PROSERNAT. An amine solution and the gas mixture are combined in a scrubber. The undesired components in the natural gas are absorbed into the solution due to their affinity to amines. The sour gases are then removed, together with tiny piping abrasion particles and other impurities, so that the solution can be reused for further washing cycles. After this cleaning process, the receptive pure amine solution is fed back into the scrubber. The first thermal processing step of the solution takes place in the ‘reboiler,’ where it is separated from the sour gases. BHS-Sonthofen has developed a complete system that comprises several components for the subsequent process steps to remove hydrocarbons and dissolved contaminants. The end result is an efficient circulation process that ensures optimal resource usage.

Three filters combined in one ready-to-go system
The overall turnkey concept devised by BHS-Sonthofen consists of three process steps in total: A candle filter separates the smallest particles from the amine solution that has been introduced. This is necessary to prevent the system from clogging up. Due to the small particle size, the filter needs to be precoated. To this end, a pumpable cellulose suspension is mixed in the precoating tank of the system, which produces a 5-10 mm thick precoat filter cake in the candle filter. Even the finest particles are suspended in this. After the pre-cleaned amine solution has passed through the candle filter, the hydrocarbons are removed in the activated carbon filter.

The activated carbon residues are removed in a polishing filter in the final step. Following this process, the amine solution is once more ready to fulfil its true purpose in the scrubber. This ‘pit stop’ in the BHS filter system therefore ensures both increased efficiency and process reliability by separating the amine solution from hydrocarbons and foreign particles that cause wear. Furthermore, only minimal amounts of amine are lost in doing so. BHS-Sonthofen supplies the three filters and the precoating unit as a complete preinstalled one-point lifting unit. The filters are ready for immediate use after connecting them to operating resources and feeding in product streams.

International collaboration with our sales partner on site
“System assembly is usually carried out in Germany entirely,” says Tim Ochel, Project Manager at BHS-Sonthofen. “But there was one restriction for this project: You can only import components that can’t be manufactured in Iran. That’s why we looked for and found a strong local partner.”

BHS-Sonthofen fully engineered and designed the five systems. The containers, steel constructions and piping were constructed by local suppliers with the support of Faris International. Special components that were not available within the country, such as pumps, valves and measuring instruments, were shipped from Germany. Final assembly was carried out near Tehran under the expert supervision of BHS engineers. Ochel is satisfied with the successful completion of the project. “The oil and gas industry has been benefiting from our turnkey filtration solutions for years. With the acceptance of these five systems at the end of April, we were able to successfully conclude the first project with our new sales partner in Iran and thus contribute to efficient and environmentally friendly gas extraction in the region.”