Patent FR-2951385-A1 (FR)
Title: Deacidification of gas e.g. natural gas comprising acid compounds, comprises contacting gas with regenerated adsorbent solution in aqueous solution, introducing mineral solution in regeneration column, and injecting heat in column
Inventor: JACQUIN MARC
IPC: B01D53/14
Filed: 2009-10-21
Abstract: The process for deacidification of a gas (1) comprising acid compounds, comprises contacting the gas with a regenerated adsorbent solution (2) in aqueous solution to produce a treated gas and an adsorbent solution loaded with acid compounds, introducing a mineral solution in a regeneration column (C1, C2) to produce the regenerated absorbent solution, injecting a quantity of heat in bottom of the regeneration column, and controlling the injected heat. The heat is controlled by determining an optimum value of minerals in acid compound of the regenerated absorbent solution. The process for deacidification of a gas (1) comprising acid compounds, comprises contacting the gas with a regenerated adsorbent solution (2) in aqueous solution to produce a treated gas and an adsorbent solution loaded with acid compounds, introducing a mineral solution in a regeneration column (C1, C2) to produce the regenerated absorbent solution, injecting a quantity of heat in bottom of the regeneration column, and controlling the injected heat. The heat is controlled by: determining an optimum value of minerals in acid compound of the regenerated absorbent solution for which the treated gas comprises an amount of acid compound lower than the specified amount and for which the regenerated absorbent solution is produced by injecting minimum quantity of heat in the regeneration column; choosing a reference interval of values of the amount of acid compounds of the regenerated absorbent solution, where the reference interval balances the optimum value, measuring the amount of acid compounds using Raman spectroscopy, comparing the measurement according to the predetermined reference interval, and controlling the amount of injected heat in the regeneration column after comparison. The composition of the absorbent solution is determined by Raman spectroscopy. The amount of minerals in the acid compounds corresponds to the amount of minerals: in carbon dioxide, which is determined by calculating the ratio between the number of moles of carbamates, nitrates and carbonates and the number of moles of active compounds; and in hydrogen sulfide, which is determined by calculating the ratio between the number of moles of hydrogen sulfide and the number of moles of active compounds. The carbamate, nitrate and carbonate species and the active compounds are present in the regenerated absorbent solution. The hydrogen sulfide species and active compounds are present in the regenerated absorbent solution. The Raman spectroscopy includes passing a monochromatic light beam through the regenerated absorbent solution for producing a polychromatic light signal, treating the polychromatic light signal by Raman spectroscopy to produce Raman spectrum, and performing a mathematical treatment of Raman spectrum for determining amount of carbamate, nitrate, carbonate and hydrogen sulfide species and the active compounds of regenerated solution. The reference interval has a value, which is 0.95-1.05 times the optimum value. The operation reflects a correlation between energy input in the regeneration column and the variation of minerals of acid compounds of the regenerated absorbent solution. The amount of heat is injected in the regeneration column by drawing a flow absorbent solution at the bottom of the regeneration column, heating the flow absorbent solution using a coolant, and injecting the flow of absorbent solution at the bottom of the regeneration column. If the measurement exceeds the interval values, the amount of heat injected in the column is increased by increasing the flow of coolant, and if the measurement is less than the interval values, then the amount of heat injected is decreased by reducing the flow of coolant. The absorbent solution is cooled until a temperature of contact before contacting with the gas.