it easy to identify differences between the vessels. In this case, a control valve is leaking across its seat, causing a high-pressure to low-pressure leak (see the red circled areas on Figure 2 ). This results in gas exiting the system through the off-gas, increasing pressure and negatively impacting operations. Additionally, off-gas fluctuations can cause issues in the upstream SMR. Routine monitoring of these process steps can easily identify such equipment problems, but it requires adequate operator training and technical expertise. UNICAT Technologies offers advanced process control systems designed to enhance operational efficiency, reliability, and safety. These systems can perform this monitoring and alert operations personnel of required maintenance. These enhancements help industries optimize their processes, improve product quality, and reduce operational costs. Magcat ® textured catalyst (catalyst innovations) As many refineries processes transition to renewable energy, the demand for hydrogen continues to rise. To meet the growing demand, modifications are necessary to boost production, with PSA units being a crucial step in increasing hydrogen output from existing SMR systems. UNICAT’s customers shared their process constraints associated with their reforming and PSA asset output limitations facilitating its innovation focus. Revamping existing hydrogen production assets offers a fast, cost-effective solution compared to installing new equipment. SMR tubes need periodic replacement or reloads, and the Magcat ® catalyst offers an innovative solution that delivers on a number of the customer improvement requests. Notably increasing plant output whilst simultaneously reducing both fuel requirements and operating temperatures facilitating significant extension of tube lifetimes. This catalyst innovation when combined with PSA adsorbent and control system upgrades to PSA cycles further enhances the output from the entire flow sheet. Older SMR catalyst pellet technologies are designed within the limitations of their compression casting techniques to achieve a compromise of properties. The shape consists of multiple holes, domes, and flutes to balance surface area and pressure drop limitations, whilst maintaining acceptable crush strengths. After 60 years of incremental development compromise, UNICAT leveraged 40 years of ceramics industry manufacturing experience to develop a liquid polymer-based pellet forming technology to remove compromises seen with ceramic compression technology. This “optimizing the compromise” technology facilitates the production of complex shapes, increasing void space and geometric surface area, leading to the development of UNICAT’s Textured Sphere technology, Magcat ® . Magcat ® enhances hydrogen and syngas production and is a direct replacement for older pellet technologies. Magcat ® is produced using gel casting techniques, where a polymer gelling agent is mixed with other dry powders. Calcination is performed at 1450–1600˚C, higher than the 1000˚C used for traditional SMR catalysts. This ensures a stronger final product that retains key chemical and physical properties under severe high-temperature and pressure conditions in the reformer. This alternative manufacturing technique offers multiple advantages over conventional reforming catalyst technology.
Feed
Product
Off-gas
H 2 recovery, %
Flow, MMSCFD
40.0
25.6
13.4
Composition, mol% H 2
76.0
99.9
33.5 10.9
84.1 84.0 84.0 84.2
CH 4
4.0 3.5
0.1
CO
10 ppmv
9.7
CO 2
16.5
-
45.9
Table 1 Reduced hydrogen recovery and production
this process. While adsorbents in PSA units are designed for continuous regeneration and typically require infrequent replacements, unexpected upsets can still cause damage. Detecting performance impacts early is vital to prevent irreversible damage and the need for replacement. For example, a large PSA unit designed to process 50 MMSCFD of syngas from SMR and produce 33.5 MMSCFD of high-purity H₂ (88% recovery) experienced a 20% capacity loss and a 4% drop in hydrogen recovery, reducing production by almost 8 MMSCFD. Efforts to increase rates resulted in off-spec product with excessive levels of CO. UNICAT’s technical experts identified that the capacity loss was primarily due to inadequate plant procedures. Although these were corrected after several years of operation, the damage was irreversible. Operations have since stabilized, but had this issue been identified earlier, the damage could have been significantly reduced or even reversed. Table 1 shows operating data confirming the reduced recovery and capacity. Case study: Troubleshooting (technology solutions) Control systems have advanced significantly over the years, paralleling improvements in computer technology. From early systems controlled by relays and timers to sophisticated systems using programmable logic controllers (PLCs) and distributed control systems (DCS), maintaining proper control over PSA steps is crucial to ensure adsorbents remain intact and do not degrade into dust. UNICAT’s latest control system upgrade utilized the existing equipment, minimizing capital expenditure (CapEx) and installation time while introducing new logic for enhanced controls. The benefits include smoother product flow, which improves downstream hydrogen compression. Better control of the off-gas significantly reduces fluctuations, enhancing stability for SMR burners and increasing H 2 production. The ability to optimize the unit across a wide range of capacities will greatly enhance hydrogen recovery and production. Stable adsorbent life is also achieved through independent control of process valves and automated learning to mitigate the impact of drifting instrumentation. In addition, rapid trends in PSA vessel pressures make
Figure 2 PSA vessel pressure trends showing leaking valves
www.unicattechnologies.com
108
Powered by FlippingBook