PTQ Q3 2022 Issue

are proportional to the flow rates and dynamically grow or shrink as operational changes take place. Digitalisation of commercial facility: reduced GHGs State-of-the-art digitalisation efforts include tools calculat - ing the impact of operating conditions on CO 2 emissions at the plant scale to reflect increasing incentives and/or con - straints to reduce GHG emissions. For instance, operational improvements such as octane optimisation in the catalytic reforming process as a function of pool requirement, or hydrogen-to-hydrocarbon molar ratio adjustment minimis - ing energy consumption, will favour CO2 emission reduction. In addition, decreased regeneration frequency achieved by operating parameters optimisation will extend catalyst life and thus reduce CO2 emissions associated with catalyst manufacturing. To correctly assess the CO2 emission impact related to the operation of a process unit, it is necessary to identify how overall plant operating conditions are fine- tuned to account for unit production target: • On extra fuel burnt at the plant level, and the carbon con - tent of this extra fuel • On generation of utilities (steam, hydrogen, power) • On fuel gas produced and consumed by the unit, both in quantity and quality (carbon content) • On pure hydrogen recovered and on associated CO2 emis - sions avoided. To be able to calculate this impact, it is therefore required to determine: • Which energy source (fuel oil, fuel gas, electricity) can be used to cope with an increase or decrease in fuel demand at the site level, as this is the key to linking any marginal duty to CO2 emission variations • Which equipment is used to adjust steam balance in case of higher or lower demand, and what is the total CO2 emis - sions associated with steam production (including boiling feed water, turbine) • What approach does the plant use to balance demand for power to supply any additional demand, and how does such additional supply affect the overall plant energy balance (cogeneration of steam, gas unbalance) • How the excess of hydrogen-rich gas from naphtha reforming is treated, especially the hydrogen part of it, as this has an impact on CO2 emissions • How the excess of hydrogen-rich gas from naphtha reforming is affecting SMR operating conditions at sites where an SMR is in operation. Using all this information gathered in collaboration with the plant and related data continuously collected, the process user can run what-if scenarios with the help of digital tools to assess the impact of operating conditions on CO2 emissions. Path forward As can be seen, accumulated operational savings for all pro - cesses/separations/fractionations from the naphtha splitter to the production of paraxylene and benzene amount to tens of millions per year (in dollars) for a paraxylene complex of ≥ 1 Mtpy capacity. Digitalisation is gradually becoming a seamless, integrated part of the state-of-the-art technology offer for aromatic

plants. In addition to operational savings and maximised production, work hours are reduced for both process licensor and process user since i) communications are facilitated by real-time data sharing and ii) user expertise is enhanced via operator training simulator (OTS) and the ability for opera - tors to gain knowledge using what-if scenarios. Knowledgeable users make the most of their exchanges with licensors’ technical assistance by contacting the pro - cess licensor regarding key issues and optimisation options. At the same time, all calculations and parameters are directly accessible to users and, therefore, no longer a topic for extended discussions. The next step for process licensors consists in providing a digital twin approach that will integrate all steps involved in the manufacturing block flow diagram and allow opera - tors to run dynamic simulations not based on design condi - tions but derived from the existing conditions at the time the dynamic simulation is performed. In other words, the operator will be able to simulate the consequences of a change in temperature, a compressor shutdown or a valve opening or closing in real time, based upon the plant condition at the time the OTS is being utilised. The digital twin approach constitutes a materialisation of the industry 4.0 concepts of predictability (“being prepared”) – and adaptability (“self-optimising”). 4 In the US, nearly 30% of GHG emissions come from the industry, including indirect emissions from the sector’s elec - tricity consumption. 5 Consequently, regulations intended to reduce industrial emissions in general, and more specifically emissions from the oil, gas and petrochemical industry, are currently under evaluation. Even if digitalisation efforts in chemical companies initially lagged the refining sector, 6 the digital transformation of the chemical industry is expected to play a crucial role in energy efficiency improvement and associated GHG emissions reduction.

References 1 Agnihotri R, Hydrocarbon Processing, 31, Jul 2018. 2 Morse P, Hydrocarbon Processing , Jan 2019.

3 Claire F, A Cotte and M Molinier, Hydrocarbon Processing , Oct 2021. 4 Fraser M S, T Anastaselos and G V V Ravikumar, The disruption in oil and gas upstream business by industry 4.0, white paper, Infosys 2018. 5 Controlling Industrial Greenhouse Gas Emissions, Center for Climate and Energy Solutions (c2es.org), consulted on 1 Mar 2022. 6 Annunziata M, It takes an ecosystem: digital transformation in the chemical industry, www.Forbes.com, Jan 2022. Philippe Mège is Head of Axens Digital Service Factory in its Digital Innovation Division. He has more than 20 years’ experience in gasoline and petrochemical processes as a Chief Start-up advisor and Technical Service Group Manager. He holds a PhD degree from the Université Paris VI, France. Michel Molinier is a consultant with Axens North America for aromatics technologies and other petrochemical processes. He has more than 20 years’ experience in the petrochemical industry and 30 years’ experience in heterogeneous catalysis. He has co-authored two book chapters, 30 peer reviewed articles, and 25 US patents. He holds a MS degree in physical chemistry from the University of Bordeaux, France and a PhD in solid state chemistry from Philipps Universität Marburg, Germany.

PTQ Q3 2022