HF-200XP

BASF HF-200XP promoted alumina spheres minimizecarbon buildup and coking, resulting in higher fluorideloadings and greater conversion rates. An improvedproduct which includes a promoter, BASF HF-200XP yields carbon pickup of 0.2-0.3%, compared to typicalcarbon pickup of 3-5% (wt.) on non-promoted aluminas.

The surface area is maximized in pores of 30-100Å to aidaccessibility of the surface active sites through bulkdiffusion. This is accomplished by controlled pore sizedistribution development in the production of alumina. Conversion improvement of 10-30% is consistently seen inthe field.

BASF HF-200XP promoted alumina spheres has all of these characteristics. The physical and chemical properties of HF-200XP are listed in the table on the next page. Its formulation is optimized so that the spent material is compatible with existing recycling applications. The 1/8” size is generally recommended for liquid applications and is preferred for gas phase applications. However, 3/16” size can be used if pressure drop is a concern.

The product streams leaving an alkylation unit are:

• LPG grade propane

• Normal butane

• C5 and alkylate

• Tar

The propane and butane streamscontain trace amounts of organicfluorides and free HF acid; therefore,they must be treated in order to meetpipeline quality specification. Most unitsuse adsorbent defluorinators, whichutilize activated alumina to decrease the fluoride content of the propane and / orbutane streams. Organic fluoridesdecompose in the presence of activatedalumina to produce aluminum fluorideand water.

Defluorinators are typically set up in a lead / guard bedscheme. These units run at temperatures in excess of350°F (177°C). The range of 400-500° (204-260°C) isrecommended for optimum reaction and to assure lowestpossible effluent specification. Operating pressures rangefrom 200-260 psig.

Fluoride concentrations of 25-50ppm typically exit the primary defluorinator and effluentconcentrations of 0-5 ppm are common from the secondarydefluorinator. Once the concentration of the primarydefluorinator exceeds 50 ppm, the bed is changed out and the secondary defluorinator becomes the lead bed.

The HF alkylation process produces high octane feedstocks that are used for blending in motor gasoline and aviation fuels. The principal reaction is the conversion of propylene or butylenes and isobutane into an isoparaffin called alkylate. HF acid is usedas the catalyst in this reaction. The important variables that affect the alkylation process are reaction temperature, acid strength, isobutene concentration and olefin space velocity. Typical reaction temperatures in the acid reactor range from 70-100°F (21-38°C) and the acid strength is normally between 86-90%. Isobutane ratios of roughly 10:1 seem to be most effective. These parameters are necessary to enhance alkylate quality and yield, and to suppress undesirable side reactions that produce heavy alkylate, acid soluble oils or polymers.