Case Study

Problem of Bottleneck in Acid Gas Removal Solved via New Packing Technology

Source: Koch-Glitsch, Inc., Otto York Division
Koch-Glitsch, Inc., Otto York Divisionottleneck in an acid gas (AG) removal plant located upstream of the natural gas liquids (NGL) fractionation unit feeding a petrochemical complex in Nigeria was being caused by low gas treatment capacity in twin absorber columns.

The sour gas is usually treated in two parallel 2550mm diameter absorbers to remove CO2 to a level of 25 ppmv maximum. The total flow rates vary from 290M Nm3/hr to as much as 600M Nm3/hr and the feed CO2 ranges from 3.67 to 1.73 mol%. The original design installed 28 valve-type trays, spaced at 450mm in each column.

Working hand-in-hand with the customer, <%=company%> performed detailed column scanning and determined that operational problems including foaming were seriously affecting both the capacity and the CO2 removal efficiency. The company recommended that the columns be revamped with packing, and a detailed process study was performed to determine the most cost-effective revamp solution. The study simulated operating data and required conditions, taking into account the customer's need for operational flexibility.

Existing trays were removed and replaced with two sections (each 3.62 meters high) of Koch-Glitsch FLEXIMAX high-efficiency random packing to provide the required number of theoretical stages. FLEXIMAX packing has a unique geometry that provides excellent radial spreading combined with superior mechanical integrity. This high performance packing makes deep beds possible without packing deformation.

The packing is supported by two layers of Koch-Glitsch FLEXIGRID to minimize rich amine retention time and reduce the risk of foaming. FLEXIGRID is a special structured packing to maximize capacity and minimize pressure drop.

Coordination between customer and supplier resulted in flawless execution of the revamp. The Koch-Glitsch solution required no welding on the vessels, minimizing downtime, and the absorbers were started up after revamp and easily met design requirements.