PTQ Q2 2024 Issue

Recycle gas compressor

Lean amine

Impact on catalyst activity

Reduced H purity CO/CO build-up

Rich amine

Increased light ends

Tail gas

HDS reactors

Amine absorber

Wild naphtha

Additional H consumption

Sour gas

Water

Gasoil stripper

Stripper reboiler

Wash water injection

Increased CO concentration

HP separator

Corrosion risk

Product

LP separator

Improved cetane number Lower density No impact on CFP

Feed

Increased HO production

Water

Vegetable oil injection

Figure 2 Co-processing impact on HDT unit

active for both reverse water gas shift (CO 2 + H 2  CO + H 2 O) and methanation (CO + 3H 2  CH 4 + H 2 O). The rela- tive extent of these two reactions determines the observed distribution between CO, CO 2 , and methane (CH 4) . If all triglycerides undergo the decarboxylation route, seven moles of H 2 will be consumed, compared to the 16 moles of H 2 consumed when all triglycerides are converted via the HDO route. In other words, there would be a 63% reduction in hydrogen (H 2) consumption. However, if all the CO 2 produced is shifted to CO, and all the CO formed is subsequently converted into CH 4 , a total of 19 moles of H 2 will be consumed by the decarboxylation route, resulting in a 19% increase in H 2 consumption. Indeed, co-processing biofeeds in an HDT (see Figure 2 ) can have various effects, both positive (pros) and negative (cons): Pros : • Co-processing biofeeds can lead to the production of intermediate and linear paraffins, thereby improving prod - uct properties.  This increase in volume swell enhances the profitability of the hydroprocessing unit.  It boosts the Cetane number, facilitating easier blend- ing into the commercial pool or reducing the need for additives.  Cold flow properties (CFP) are minimally impacted by biofeeds co-processing options. Cons: • Upstream reactors uniform corrosion risk – FFAs corrosion.

• Increased H 2 consumption (lipids HDT reactions). • Reactors cycle length reduction and performance decrease:  Catalyst deactivation and reactor pressure drops increase:  Production of CH4 /CO/CO 2 /H 2 O by conversion of lipids followed by water gas shift (WGS) equilibrium and production of C 3 H 8 by removal of the glycerol group.  CoMo catalyst active sites partial Inhibition due to CO.  H 2 partial pressure decrease.  Catalyst active sites partial deactivation due to Ca and Mg phosphate.  Fouling issues (phospholipids, peroxides, olefins and di-olefins, metals). • Reactor effluent air cooler (REAC) – fouling, uniform cor - rosion and pitting corrosion risk by chlorides in the effluent reactor side:  Increased organic and inorganic chloride concentration in biogenic feedstock.  H 2 O increased production and increased relative humidity (RH):  HDO pathway.  Increased water quenching due to higher exother- micity because of the lipids HDT reaction. • Low-pressure (LP) separator/stripper overhead/amine section – wet CO 2 corrosion risk:  CO 2 production. • Compressor capacity limitations:  Light ends load increase.

PTQ Q2 2024