8/3/2019 0071455914_ar043

1/4

CHAPTER 10.7

UOP MOLEX PROCESS

FOR PRODUCTIONOF NORMAL PARAFFINS

Stephen W. SohnUOP LLC

Des Plaines, Illinois

DISCUSSION

The separation of normal paraffins from isoparaffins is done commercially for a numberof reasons. In the lighter hydrocarbon range, isoparaffins are often more desirable becauseof their higher octane values and their superior gasoline alkylation characteristics. In theheavier range, normal paraffins are typically the desired product because of the benefitsderived from their linearity in the production of plasticizers, linear alkylbenzene sul-fonates, detergent alcohols, and ethoxylates.

This chapter discusses the specific application of the UOP* Molex* process to the sep-aration of normal paraffins from isoparaffins. Although not limited in its application to aparticular processing mode or carbon number, the Molex process is most often used in therecovery of normal paraffins for plasticizer and detergent-range applications. Typical car-

bon numbers are C6 to C10 for plasticizers, C10 to C14 for linear alkylbenzenes, and C10 toC18 for detergent alcohols.

The UOP Molex process is an established, commercially proven method for the liquid-phase adsorptive separation of normal paraffins from isoparaffins and cycloparaffins usingthe UOP Sorbex* separations technology (see Chap. 10.3), which uses zeolitic adsorbents.Isothermal liquid-phase operation facilitates the processing of heavy and broad-rangefeedstocks. Vapor-phase operations, in addition to having considerable heating and cool-ing requirements, require large variations of temperature or pressure or both through theadsorption-desorption cycle to make an effective separation. Vapor-phase operations alsotend to leave a certain residual level of coke on the adsorbent, which must then be regen-erated on a cyclic basis. Operation in the liquid phase allows for uninterrupted continuousoperation over many years without regenerations.

Refer to Chap. 10.3 for details of the operation of this separations technology. Figure10.7.1 illustrates the general design characteristics of such units.

10.75

*Trademark and/or service mark of UOP.

Source: HANDBOOK OF PETROLEUM REFINING PROCESSES

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)Copyright 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.

8/3/2019 0071455914_ar043

2/4

YIELD STRUCTURE

Typically, a UOP Molex process unit produces normal paraffins at about 99 wt % puri-ty and at about 98 wt % recovery, depending on the amount of adsorbent used relativeto the volume of feed.

ECONOMICS

To a certain extent, the economics of the UOP Molex unit is dependent on the feed quali-ty, because some prefractionation and hydrotreating may be required to control the levelof contaminants that might otherwise affect unit performance or adsorbent life. If the feedis assumed to have been properly treated, the estimated erected cost of a UOP Molex unit,feeding 383,000 metric tons per year (MTA) (844 million lb/year) of a paraffinic kerosenein the C10 to C15 range with about 34 percent normal paraffins, was about $25 million in1995. This unit was designed for the recovery of 96,000 MTA (211 million lb/year) of nor-mal paraffins at 99 percent purity. This cost represents the fully erected cost within batterylimits for a particular UOP Molex unit.

The utility requirements for such a unit per metric ton of product are as follows:

Electric power, kWh 54.3

Hot-oil heat, 103J/h (Btu/h) 120 (114)

Cooling water circulated [15C (27F]) rise], m3 (gal) 5.1 (180)

10.76 SEPARATION PROCESSES

FIGURE 10.7.1 UOP Molex process design characteristics.

UOP MOLEX PROCESS FOR PRODUCTION OF NORMAL PARAFFINS

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)Copyright 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.

8/3/2019 0071455914_ar043

3/4

UOP MOLEX PROCESS FOR NORMAL PARAFFINS 10.77

COMMERCIAL EXPERIENCE

As of early 2002, a total of 26 UOP Molex process units had been commissioned. Another

three were in various stages of design or construction. Product capacities ranged from2500 MTA (5.5 million lb/year) to 155,000 MTA (340 million lb/year).

UOP MOLEX PROCESS FOR PRODUCTION OF NORMAL PARAFFINS

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)Copyright 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.

8/3/2019 0071455914_ar043

4/4

UOP MOLEX PROCESS FOR PRODUCTION OF NORMAL PARAFFINS

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)Copyright 2004 The McGraw-Hill Companies. All rights reserved.

Any use is subject to the Terms of Use as given at the website.