PTQ Q3 2022 Issue

Component Flow

HA Splitter

C10+ Product

Trans+

LP Purge

Tol Column

Bz Column

Bz Product

O Gas C5 Cut Net Gas LPG

PX Product

Non-Aro.

Aromiser Feed

Eluxyl

Xylene Splitter

Xy Max

Aromiser

Morphylane

Ref. Splitter

Non-Aro BZ Tol PX MX OX EB A9+ A8 (Detailed N/A)

Feed Summary

Products Summary

A9+

Net gas

Tol

PX Morph, Ranate LP Purge C10+ LPG

Non-Aro

Tol A8

Fuel gas Bz C5 Net gas

A9+

Fuel gas

LPG

LP Purge C10+

Non-Aro

Morph, Ranate

Figure 6 Aromatics complex in operation

the hydrogen-to-hydrocarbon molar ratio, and the catalyst circulation rate, for instance, to define the best set of operat - ing conditions. The unit operator has access to daily recommendations compared to the previous day, with associated expected performance improvement. Applied to a 1 Mtpy paraxylene (PX) complex achieving ~1% product gain and based on the regional PX-naphtha spread, this strategy increases the annual PX production by 10,000 tons/year, which represents a net benefit of approximately $5M/year. The distillation trains are also scrutinised in order to improve separation efficiency, hence minimising aromatic losses while optimising energy efficiency by adjusting oper - ating parameters according to real conditions rather than design conditions. Figure 4 shows the real-time status of a transalkylation unit. The process performance overview includes feed rate and weight hourly space velocity, reactor temperature and pressure, hydrogen-to-hydrocarbon molar ratio, conversion per pass, benzene and xylenes yields, and material bal - ance calculation, among others. Alert functions attract the viewer’s attention to operation within design specifications (in green), outside design specifications but within operat - ing constraints (in orange), or outside operating constraints (in red). The operator can also monitor the recovery of C 9 , C 10 and C 11 aromatics at the overhead and bottoms of the heavy aromatics column, and apply changes as needed using the ‘what if’ tool to calculate the impact of such changes on the transalkylation process performance and output. A separate tool projects the end of cycle for the transalkylation catalyst using models based on robust regression applied to historical

data, allowing the plant to manage the catalyst remaining useful life efficiently. A general performance survey with associated alerting can also be set up for the paraxylene separation process. Suboptimal adsorber tuning survey, zone effect tracking, individual bed pressure drop calculation (see Figure 5 ), and associated alerting are key indicators to always maintain the desired level of paraxylene purity. An inferential model built by machine learning calculates the optimal tuning parame - ters to achieve optimal recovery for a given purity, consider - ing the actual molecular sieve ageing and unit status. These continuous recommended adjustments represent a net gain of several $M/year for an aromatic complex with a capacity of 1 Mtpy paraxylene. Figure 6 provides an overview of an aromatics facility in operation. The operator can visualise the performance aggregate of all processes (heavy naphtha reforming, ben - zene and toluene extraction, paraxylene recovery, xylenes isomerisation, and aromatics transalkylation). Individual unit capacities are displayed, as well as benzene and paraxylene production, purity and yields, by-products yields, and pie charts summarising molecular distribution in the feed and the product. Improved operation via real-time digital performance monitoring: overall complex An optimisation tool provides calculations of achievable margins based on feed and product prices inputted by the user. Lastly, a Sankey diagram presents a view of streams entering and leaving the complex, as well as inlets/effluents of processes and/or fractionation steps within the com - plex, where the width of the lines representing the flows

PTQ Q3 2022