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Korpelshoek M.,CDTECH | Rock K.,CDTECH | Samarth R.,CDTECH
Hydrocarbon Engineering | Year: 2010

COTECH has developed a selective treatment method for the full range FCC gasoline that optimizes the severity for treating different cuts of gasoline to maximize sulfur removal while minimizing olefin loss. The first step is to treat the lightest fraction of the gasoline in a light cat naphtha (LCN) CDHydro® unit where the RSH is nondestructively removed. The LCN CoHydro unit is not a hydrodesulfurisaton step. The unit works by performing an addition reaction between the RSH and the contained diolefins over the catalyst to form a heavier sulfide (RSR). The light product (LCN) from the LCN CDHydro column has very low RSSH, a very high olefin concentration, a high octane rating, and a relatively high Reid vapor pressure (RVP).Since the CDHDS unit performs distillation, there is an opportunity to isolate two additional FCC gasoline fractions to increase blending flexibility and control the end point of the product. The reduction of sulfur in FCC gasoline by hydrosulfurisation also results in some saturation of the olefins in the gasoline.

Vogt T.,CDTECH | Cross W.,CDTECH | Kapraun C.,CDTECH
NPRA Annual Meeting Technical Papers | Year: 2010

CDTECH conducted an engineering study to evaluate the feasibility of the conversion of an hydrofluoric acid (HF) alkylation unit to a CDAlky sulfuric acid alkylation unit. The feed use was a FCC derived mixed olefins with the assumption that most of the propane and propylene was recovered upstream of the alkylation unit. Major differences in feed pretreatment, reaction, refrigeration, catalyst regeneration, and fractionation are presented for HF alkylation and sulfuric acid alkylation. Converting an HF alkylation unit to a CDAlky low temperature sulfuric acid alkylation process is possible with major pieces of equipment being retained. However, because of the significant differences between the sulfuric and HF acid alkylation processes, additional major capital investment is required for a conversion. The combination of a changing regulatory environment and North American gasoline market may provide a valuable opportunity for refiners to consider alternatives to alkylation including conversion of C 4 olefins to higher value petrochemical feedstocks. This is an abstract of a paper presented at the NPRA Annual Meeting (Phoenix, AZ 3/21-23/2010).

Cross W.,CDTECH | Kapraun C.,CDTECH | Vogt T.,CDTECH | Korpelshoek M.,CDTECH
Hydrocarbon Engineering | Year: 2010

CDTECH undertook an engineering study to evaluate the feasibility of converting an hydrofluoric acid (HF) alkylation unit to a CDAIky® sulfuric acid alkylation unit. The water, mercaptans and other contaminants in HF alkylation are removed from the hydrocarbon feed prior to entering the reaction section and the materials dilute the HF catalyst, requiring its regeneration. The contaminants of sulfuric acid process dilute the sulfuric acid catalyst, resulting in high acid consumption. HF alkylation units have tighter feed impurity specifications than sulfuric acid alkylation units. HF is mixed with hydrocarbons using an eductor and enters a tubular reactor to a settler. The use of a single CDAIky® reactor allows for reduced plot space in the reaction section compared to parallel contactors used in other sulfuric acid alkylation processes. HF settles out from the reactor hydrocarbons and any entrained or dissolved HF is distilled from the product alkylate.

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