Poisoning of Ammonia Synthesis Catalyst Considering Off-Design Feed Compositions

Abstract

Activity of ammonia synthesis catalyst in the Haber-Bosch process is studied for the case of feeding the process with intermittent and impurity containing hydrogen stream from water electrolysis. Hydrogen deficiency due to low availability of renewable energy is offset by increased flow rate of nitrogen, argon, or ammonia, leading to off-design operation of the Haber-Bosch process. Catalyst poisoning by ppm levels of water and oxygen is considered as the main deactivation mechanism and is evaluated with a microkinetic model. Simulation results show that catalyst activity changes considerably with feed gas composition, even at exceptionally low water contents below 10ppm. A decreased hydrogen content always leads to lower poisoning of the catalyst. It is shown that ammonia offers less flexibility to the operation of Haber-Bosch process under fluctuating hydrogen production compared to nitrogen and argon. Transient and significant changes of catalyst activity are expected in electrolysis coupled Haber-Bosch process.

Optimasi Penggunaan Benfield Diethanolamine Pada Absorber E-201 Unit Treating Ammonia PT X

“…Syngas yang digunakan harus memiliki kemurnian tinggi, dengan kandungan karbon dioksida, asam sulfat, dan senyawa pengotor lainnya yang rendah. Jika kandungan senyawa pengotor tinggi, proses pembuatan ammonia tidak akan berjalan optimal [1].…”

“…Pengurangan kandungan CO2 sangat penting dilakukan karena komponen CO₂ bersifat asam dan korosif yang mana dapat menyebabkan proses pembuatan ammonia tidak berjalan dengan baik. Dan apabila kandungan CO₂ yang terikut melebihi batasan yang ditentukan maka kebutuhan syngas untuk direaksikan menjadi CH4 semakin meningkat sehingga berpengaruh terhadap ammonia yang dihasilkan akan berkurang [1]. Maka dari itu, diperlukan kondisi optimal supaya proses produksi ammonia berjalan dengan efisien dengan cara mengatur beberapa variabel seperti aliran masuk, tekanan, serta temperatur selama variabel tersebut masih berada di dalam keadaan desain operasi.…”

How sensitive is a dynamic ammonia synthesis process? Global sensitivity analysis of a dynamic Haber-Bosch process (for flexible seasonal energy storage)

“…Here, we perceive that the HBS process can be used for higher ramp-ups until 80% while avoiding large standard deviations during operation. In practice, the sudden increase of the temperature profile could affect the reactor operation or damage the catalyst [77].…”

Poisoning and Reuse of Supported Precious Metal Catalysts in the Hydrogenation of N-Heterocycles, Part II: Hydrogenation of 1-Methylpyrrole over Rhodium

“…As well-known [2][3][4][5][6][7][8][9], several types of catalyst deactivation (fouling, poisoning, thermal degradation, vapour-solid and/or solid-solid reactions, attrition/crushing) can be responsible for decreasing or ceasing the activity of catalysts, among which poisoning is a strong chemisorption of different species (products, reactants, or impurities) on the catalytically active centres blocking the surface chemical reactions. It has also long been known [10][11][12][13][14][15][16][17][18][19][20][21][22] that nitrogen-containing compounds have inhibitory influences on the hydrogenation catalysts due to their non-bonding electron pairs. This effect can be eliminated by conversion of these substances to a form in which the N atom is protected-for example, by adding protic acids (e.g., H 2 SO 4 , HCl) [12].…”