Comparison of isobutane recycle loops
DuPont Clean Technologies (DuPont) launches DuPont ConvEx HF alkylation conversion technology, which reportedly enables refiners to convert volatile and toxic hydrofluoric acid (HF) alkylation units to the safer sulfuric acid alkylation technology. The new technology also offers refiners the opportunity for capacity increases at minimal additional cost, according to DuPont.Historically, the expense of converting from HF to sulfuric acid alkylation was estimated by the industry at 80% of the cost of a grassroots sulfuric acid alkylation unit of a similar size, says DuPont. By reusing existing equipment, conversion with DuPont ConvEx technology is reportedly estimated to be lower – approximately 40-60% of the cost of a grassroots sulfuric acid alkylation unit. In situations where plot space is available near the existing facility, downtime can be reduced by installing new equipment during normal operations, according to the company.
Fundamental to the expansion aspect of the DuPont ConvEx technology is the difference in the way in which isobutane is recycled between the HF and sulfuric acid alkylation technologies. HF alkylation units provide all isobutane to the reaction zone by recycling it from the fractionation section, while sulfuric acid alkylation units provide half of the required isobutane from fractionation and half from the refrigeration section. This difference is significant, according to DuPont, as conversion from HF to sulfuric acid alkylation means isobutane required from fractionation is cut in half, freeing up fractionation space and, therefore, effectively doubling the capacity of the alkylation unit without requiring any significant changes to the fractionation equipment.
For more information, visit: www.cleantechnologies.dupont.com
