58- Discussion on the design of multi-factor swirl separator for natural gas separation at wellheads
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This post was last edited by luoli519 on 2020-1-4 at 11:46. Some time ago, the gas separation at the wellheads in a gas field operated by a subsidiary of CNPC was not satisfactory, which led to frequent failures of the compressors. The owner has requested our company to carry out a technical upgrade and renovation of their wellhead gas separator. Let’s all discuss together the design and modification issues of this wellhead gas separator.
This post was last edited by luoli519 on 2016-12-2 at 18:37. The depth of the gas source in this well is 5870 meters. Its operating parameters are: 1. Operating pressure: 9.1 MPaG; 2. Operating temperature: 30℃ ； 3. Gas composition of the blowout sampling: (v%) C1, 91.47; C2, 0.025; C3–C6, ~0; H2S, 1.372; CO2, 6.45; N2, 0.657; He, 0.018 ； H2, 0.007.4; gas flow rate: 18.66 MMSCFD; the gas phase carries along gums, waxes, condensate oil, water, sand, etc.
The owner’s original wellhead gas separator initially used a purely gravitational sedimentation separation method.
Under these operating conditions, the density difference between the gas and liquid phases is only 39 Lb/ft^3, which means that gravity-based sedimentation separation will inevitably be ineffective.
So, the owner found a supplier of wire mesh demisters and installed a layer of wire mesh at the top of the separator cylinder. But within less than a month of operation, the screen became clogged, and the low pressure at the compressor inlet forced the compressor to shut down.
The wire mesh demister supplier advised the owner to install an additional separator as a spare, to facilitate switching and replacing the internal components when they become clogged.
At the recommendation of the design institute, the owner contacted our company and requested to hold a tripartite technical meeting involving the owner, the design institute, and Novel Company.
This post was last edited by luoli519 on 2023-10-2 at 15:37. The owner and the design institute initially consulted us regarding the G50 type vane separator technology. Based on our analysis of the pressure under the aforementioned operating conditions as well as the density difference between the gas and liquid phases, we informed the owner and the design institute that the operating pressure in these conditions is 9.1 MPaG, and the density difference between the gas and liquid phases is less than 40 Lb/ft^3; therefore, the use of a G54 multi-factor cyclone separator would be superior to a G50 vane separator.
It is even better than the traditional Chevron baffle.
This post was last edited by luoli519 on 2023-10-2 at 15:37. Generally speaking, the optimal operating pressure for vaned separation internals should be below 8.5 MPaG, with a maximum of no more than 9.0 MPaG. This is because the gas phase is severely compressed, the difference between the density of the gas phase and that of the liquid phase decreases, and the separation efficiency drops.
This post was last edited by luoli519 on 2023-10-2 at 15:38. Although, under the same operating conditions and flow rates, the cost of the internal components for the G54 multi-factor swirl separator technology is higher than that of the G50 vane separator internal components. However, due to the intense compression of the gas, the volumetric flow rate under operating conditions will not be very high, and the cost difference in the internal components will also **decrease**.