More answers to these questions can be found at www.digitalrefining.com/qanda
Q What are themain issues you have experienced in revamps to add in CO 2 capture? A Ken Chlapik, Market Manager - Low Carbon Solutions, JohnsonMatthey, email@example.com The main issues we have seen in CO 2 capture based revamps on existing syngas plants are: 1) Carbon pricing: CO 2 capture comes at a cost; whether the region has an incentive or a tax, is it enough to drive the investment? 2) Carbon storage: some states and countries do not have sequestering sites, and transport costs to other regions can be prohibitive. 3) Capital cost: during the pandemic, many companies have reduced capital budgets by 20% and have priori- tised upstream methane emissions and renewable fuels in their strategic plans. 4) Plot space required: many facilities are in metropoli- tan areas with limited space for development, with some CO 2 capture solutions requiring more space than the plant producing the emissions. Johnson Matthey’s Low Carbon Solutions portfo - lio utilises Advanced Reforming technology to provide enhanced carbon capture, resulting in up to 95% CO 2 capture with 40% lower plot space requirement and 30% less capital than post-combustion solutions. Q Howhastheintegrationofalternativefeedstocks impacted your overall energy efficiency (any pluses and minuses)? A Nicolas Bouvier, Renewable Hydroprocessing Technologist, Axens, nicolas.BOUVIER@axens.net; Benoît Durupt, Hydrotreatment Global Market Manager, Axens, benoit.DURUPT@axens.net The main incentive for using alternative feedstock is to reduce the overall CO 2 footprint of the refinery, which is a key objective for any operator today. This integration comes with some consequences, especially on hydro- treating units, where those impacts are as diverse as the feedstock types on the overall energy efficiency of the refinery. For renewable lipids, the oxygenated compounds in those feeds make this type of feed more hydrogen intensive and exothermic than fossil feedstocks. With adequate heat management and high-efficiency heat exchangers like ZPJE spiral tube heat exchangers, those feedstocks can generate sufficient heat to reduce or avoid the use of fired heaters in hydroprocessing. At the same time, it could also generate steam for the refinery net - work, which is a plus. In addition, propane is a valu- able by-product of glycerides hydroprocessing. It can be either valorised as a bio-LPG product or used to replace advantageously natural gas as a steam reforming feed- stock or refinery fuel gas, thus decreasing the overall car - bon intensity.
On the other hand, alternative feedstocks also have variable content and impurities that can negatively impact the overall energy efficiency. For example, waste based feedstocks such as plastic pyrolysis oil can have very high levels of metals or chloride due to their various origins and initial treatments, which will have a negative impact on global heat integration. Metals will require increased reactor temperature due to catalyst poison- ing and reduced cycle length, while chloride will make heat integration more complex due to corrosion issues. In addition, other contaminants can be sources of pressure drop build-up and subsequent operational issues. In this context, even low incorporation rates of those pyrolysis oils can negatively impact the overall energy efficiency. However, a combination of equipment, specialty grad- ing, specific catalysts, and unique process expertise can mitigate these negative effects. Axens’ EquiFlow Hy-Clean filtering trays, ACT series specialty bed, the latest HR 700’s series, air preheater (APH) technologies, revamp studies are among Axens’ proven solutions to overcome the challenges of any alter- native feedstocks co-processing. They maximise their rate of incorporation in existing assets with an overall positive impact on energy efficiency. A Tom Chupick, Principal Consultant – Carbon and Energy Management, Petrogenium, firstname.lastname@example.org It depends. The blending of bio-components directly into the refinery gasoline pool tends to reduce reformer throughput, which requires higher severity to sustain hydrogen production. This is usually an energy inten- sity index penalty (depending on reformer optimisation and constraints). Coprocessing bio-components in HDS feeds increases reaction heat and hydrogen consump- tion, which may appear to lower HDS reaction furnace duty, but may not translate into a site-wide energy ben- efit when hydrogen supply is considered. Note that most refineries make incremental hydrogen from 75% efficient steam methane reformers. Importing green/blue hydro- gen reduces the site’s own energy use and CO 2 emissions but has an even lower efficiency when off-site energy use is considered (albeit offset by lower Scope 2 CO 2 emis- sions). Dedicated biorefinery units or massive hydrogen imports can lead to fuel/steam system imbalances with more inefficiencies. To summarise, alternative feeds usu - ally have a favourable (accounting) impact on local pro- cess unit energy efficiency, which can be misleading when the energy (and resource) efficiency across a wider boundary is considered. Any experiences you can share regarding the imple- mentation of carbon management/digital data tools? A Marie Duverne, Technical Support Digital Transformation Leader, Axens, Marie.DUVERNE@axens.net; Pierre-Yves Le Goff, Global Market Manager, Reforming & Isomerization,
PTQ Q2 2022 9
Powered by FlippingBook