Dafne Plant

The Dafne Plant is an innovative apparatus with dynamic molecular sieves. It finds its main field of application in the dehydration of gases and has been designed to obtain the dew point of the gases according to standard specifications (for example: - 5 ° C @ 72 Bar): the gas therefore comes to be in the ideal conditions of use and transport while avoiding the formation of unwanted hydrates.

The process uses dynamic molecular sieves (transported fluid bed), of completely innovative engineering. The regeneration phase is carried out with very small quantities of the same preheated gas: no foreign gas molecules are introduced.

The plant has a very competitive construction cost, compared with a so-called traditional plant and completely negligible dimensions.

Adopting it also reduces the entire "blow-down" system and therefore not only constitutes a significant technological leap forward in the field of wellhead treatment but has a significant positive impact on the environment and on the reduction of greenhouse gas emissions as in case of need, the volumes of depressurized gas sent to the emergency torch are much lower. For example, just 33,500 kg / h compared to 134,000 kg / h of traditional glycol systems of equal capacity. This also constitutes a further strong source of savings as it makes it possible to install less high and expensive emergency torches and to reduce the spaces of respect. Lastly, with the use of the Dafne Plant, even near the base of the emergency torch, the thermal radiation produced never reaches dangerous levels for humans (irreversible lesions 5.0 kW / m² or reversible lesions 3.0 kW / m²).

Dafne Plant is easily convertible into a chemical production plant, with the addition of some elements or with small variations: in this way it is possible to produce methanol or alkanes or other chemicals, while maintaining the main installation structure.

To reach the dew point, Dafne Plant uses dynamic molecular sieves, of completely innovative engineering, stacked in micro filling towers.

The process occurs in a succession of stages:

• The gas supply takes place through an addition system operated by molecular sieves directly in the extraction areas, before being introduced to the transport lines and, therefore, to the final use phase.
• The innovative molecular sieve of zeolites is used dynamically with the same gas supply lines and is controlled by an innovative instrumentation capable of coordinating all the variables through a specially developed mathematical model.
• The transport cycle, operated with the aid of the molecular sieve, is performed by handling it with the same gas, thus reducing the risk of any explosions, and by means of special sealed and compartmented dosing valves placed between the gas, the sieve itself and storage / regeneration areas.
• The regeneration phase is carried out with the same preheated gas and in a very small current. So no foreign gas molecules are introduced.
• The environmental impact is decidedly negligible compared to that caused by the other systems examined. In the event of an emergency, in the presence of the Dafne Plant the volumes of depressurized gas sent to the emergency torch are far lower. For example, just 33,500 kg / h compared to 134,000 kg / h of traditional glycol systems of equal capacity. Therefore, in the emergency torches, less quantities of gas are burned and the spaces of respect for them and for the blow-down lines are drastically reduced. Thermal pollution is also greatly reduced as the thermal radiation produced by the Dafne Plant stops at ⅕ than that emitted on average by traditional glycol systems of equal capacity.
• Last but not least, the plant has a very competitive construction cost, from about ½ to about ⅓ of a traditional plant. Not to mention that it is possible to install less high and expensive emergency torches in the systems and that the spaces of respect for them and for the blow-down lines are drastically reduced.

The consumption of zeolites itself during the process phases is decidedly small since most of them are recovered and recycled.

Dafne Plant is a "minimum duty" system that is automatically recalculated, moment by moment, from the mathematical model specially developed by us and which controls the system, adapting it dynamically to the changes in the gas to be treated.

In this way all energy wastes are avoided and management costs are minimized.

In the Dafne Plant therefore there is no need for a constant rain of glycols to be distilled at each cycle. There is no need for cooling systems for bulky beds or for heating large quantities of gas to remove impurities. The sieves, being dynamic, undergo uniform wear and wear that does not penalize their efficiency. Likewise, zeolites are used in a homogeneous way which involves a gradual exhaustion.

The following graph highlights the thermal radiation produced by the emergency torch in a specific case of an extraction installation or a treatment plant in which, to reach the dew point, one uses the Dafne Plant (yellow) or a traditional glycol plant  (red) . In an emergency, the volumes of depressurized gas sent to the emergency torch are far lower. For example, just 33,500 kg / h compared to 134,000 kg / h of traditional glycol plants of equal capacity; as a consequence, less high and expensive emergency torches can be installed and the spaces of respect for them and for the blow-down lines are drastically reduced. In fact, with the use of the Dafne Plant, even near the base of the emergency torch, the thermal radiation produced never reaches dangerous levels for humans (irreversible lesions 5.0 kW / m² or reversible lesions 3.0 kW / m² ).

Currently, among the so-called traditional systems used for the dehydration of the gases and to bring the gas to the dew point, the glycol washing columns are the absolute most widespread method. Given the small size, with a height of up to 15 meters each and a width often greater than 2 meters, their use involves the occupation of large volumes of space. To overcome this, the towers are usually installed in groups side by side; this closeness, however, entails the disadvantage of the serious risk that if one were to catch fire, the fire could spread rapidly to the whole group.

The possibility of simultaneous depressurization of numerous glycol washing columns, sometimes even from 4 to 6 together, means having to install emergency torches in the system capable of managing these enormous flow rates which will produce, play strength, massive flare-ups and, consequently, it will be necessary to have huge areas of respect.

Often, there is the risk of having to manage real and unexpected explosions, which do not correspond to the peak flows estimated in the design phase by the volumes involved and therefore find process equipment installed too close to the torches, or areas of absolutely insufficient respect or even realize that they have staff members who perform routine operations in areas that should only be crossed in cases of emergency for rescue operations and where only authorized personnel should have access, precisely only in an emergency, equipped with special suits.

In addition, frequently, you can also encounter extreme situations: such as civil constructions built almost close to the plant, well within the safety zone and with values ​​of resistance to thermal impact below those required by the API. It may even happen that building permits are issued by the city authorities, in absolute good faith, in areas to be considered as respecting, even if the plant is already in operation.

With more than a quarter of a century of direct experience in the field in the natural gas sector, as recognized avant-garde designers in this field and to remedy the situation described above, we have tried to find valid alternatives for the management of the process in itself, alternatives that were cheaper and, above all, prevented such accidents.

To do this, we analyzed the methods currently used for the dehydration of gases and to bring the gas to the dew point and, for each one, we highlighted the main critical issues: