TransPlusSM TOLUENE AND C9+ AROMATICS TRANSALKYLATION FOR XYLENES PRODUCTION

THE LATEST ADVANCE IN TRANSALKYLATION TECHNOLOGY

Through an exclusive agreement with ExxonMobil Chemical Company, Axens offers the TransPlus toluene and C9+ aromatics transalkylation technology developed by Mobil and the Chinese Petroleum Corporation (CPC) to produce mixed xylenes. Fitting ideally into your grassroots paraxylene production plans, this leading edge technology converts C7 and C9+ aromatics to added xylenes, thus boosting paraxylene production at the expense of lower-valued byproducts.

TECHNOLOGY ADVANTAGES

The TransPlus process offers advantages over the competition, such as: • High C9+ aromatics co-processing capabilities • Ability to process most C10-C11 aromatics • Lower H2/Hydrocarbon ratio requirements • Higher space velocities • Lower ethylbenzene content in the C8 aromatics

recycle loop • Benzene co-product purity over 99.85 wt% • Low catalyst aging rate; long catalyst life • Regenerable catalyst; long lifetime

SUPERIOR CATALYST

The TransPlus catalyst, achieves superior yield performance by employing a special formulation that maximizes desirable transalkylation, disproportionation, and dealkylation reactions and minimizes undesirable side reactions. The robust nature of the catalyst

accommodates most of the C10-C11 aromatics in the C9+ aromatics feedstock. The lower H2/HC mole ratio and high space velocity result in substantially lower capital and operating costs relative to competing technology.

Typical TransPlus catalyst performance gives cycles in excess of several years even when processing feedstock containing over 60 wt% C9 aromatics.

PROCESS DESCRIPTION

In the TransPlus process (see overleaf), the feed is a mixture of fresh and recycled toluene together with fresh and recycled C9+ aromatics. The mixed feed is combined with hydrogen-rich recycle gas, preheated and passed through the reactor where transalkylation reactions take place. In the main reaction, one molecule of toluene and one molecule of trimethylbenzene form two molecules of xylenes distributed in thermodynamic equilibrium. Other reactions also take place such as disproportionation and dealkylation which generate high-purity benzene and more xylenes. The reactor effluent is cooled by heat exchange and the liquid product is separated from the recycle gas, stripped to remove light ends and fractionated to remove benzene and toluene distillate. The bottoms from the fractionation section are then recycled to the paraxylene and orthoxylene recovery section, shown here as a xylenes splitter, and the Eluxyl process. Toluene recycle is recovered from the upstream BT separation section which is part of the paraxylene production scheme. High purity benzene co-product is also recovered from this section.

CW

Eluxyl

BT

C8Aromatics

H2

Off Gas

C10+ Aromatics

Paraxylene

Benzene

Raffinate

COMMERCIAL EXPERIENCE

The first TransPlus unit was put on stream in 1997 at CPC’s petrochemical plant in Taiwan where an existing unit was modified to TransPlus service. This technology builds on ExxonMobil’s extensive experience in the field of toluene disproportionation which dates back to the 1970s. TransPlus has today thirteen industrial references worldwide.

The TransPlus process is ideally suited to boost paraxylene production in the ParamaX® technology suite, particularly when maximum paraxylene yield is required at the expense of toluene. When combined with other technologies, a full utilization of virtually all the aromatics produced from naphtha feed is possible. TransPlus is a trademark of ExxonMobil. ParamaX is proprietary process name of Axens.

Jan.

11-T

rans

Plus

Simplified TransPlus process flowsheme

TransPlus Unit