PTQ Q1 2023 Issue

Aqueous NH 3 • 26 Baumé

SWSPlus NH 3 can be blended with Haber NH 3 • Haber NH 3 is made from natural gas and air • Haber NH 3 is the industrial standard • ‘Haber ammonia’ is analogous to saying ‘Claus qual - ity sulphur’ Among SWSPlus licensees the type of NH 3 recovered: • 45% Anhydrous

• 28-30 wt% NH 3 (sometimes at 19 wt% to avoid pres- surised storage to avoid regulatory reporting requirements) • 0.897 specific gravity maximum at 60ºF (15.6ºC) • <0.05 wt% non-volatile matter • Low vapour pressure at ambient temperatures. In the US, it is common practice to store NH 3 as 19.0 wt% rather than the 28-30 wt% previously shown. This is due to reporting requirements from the US Environmental Protection Agency (EPA) on quantities over 20 wt%. Worldwide, the main trading hubs are in Tampa, Yuzhny (Ukraine), and the Caribbean. Historically, 400 USD/tonne is a good value and is used in the case study herein. Due to geopolitical events surrounding the Ukraine conflict and supply-chain challenges, NH 3 spot prices skyrocketed to over 1200 USD/tonne. Although that value may soften in the long run, higher than historical values are supported by recent inflation, corn-derived ethanol mandates in the US, and increased demand in Asia (driven by China and India). Historical pricing of NH 3 is shown in Figure 4. Worldwide demand also greatly exceeds the potential production from a refinery or series of refineries. A study for what would have been the world’s largest SWSPlus showed the unit recovering 76,000 metric tonnes NH 3/ year. Compared to the world’s 2020 production of 147 mil - lion metric tonnes, this represents <0.05% of the total NH3 produced. Case study: Comparison to a new SRU complex As a case study, a facility considered has 1000 US gpm (227 tonnes/hr) of sour water and recovers 700 MTPD sul - phur from its crude (see Figure 5 ). A proposed expansion of the refinery keeps the same sour water but requires an incremental 500 MTPD sulphur. What to do? • The status-quo answer is to add another sulphur train (SRU, TGTU, incinerator, sulphur degassing, sulphur storage) • A second option is to use SWSPlus to debottleneck the existing SRU train and use the liberated space for the new sulphur load • A third option is to use a Bolt-On Absorber to concen- trate the NH 3 recovered in the SWS and feed that to a smaller SWSPlus. The design criteria used for the SRU were not weighted

• 25% Aqueous • 30% Incinerate

Status Quo: Additional SRU complex for 500 MTPD incremental sulphur from AAFG

Incremental sulphur capacity, MTPD SRU feed HS concentration in amine acid gas , %

500 93 2 0.8 1000/227 Zero

SRU number of catalytic stages SRU design burner pressure, barg Sour water ow, US gpm or tonnes/hr

Incremental sour water ow, US gpm or tonnes/hr Feed ammonia concentration in sour water, % Feed H 2 S concentration in sour water, wt%

2.0 4.0

Table 1

Sour water design parameters for both SWSPlus and Bolt-On

Sour water ow, US gpm or tonnes/hr SWSPlus inlet temperature, C Feed ammonia concentration in sour water, wt% Feed H 2 S concentration in sour water, wt% Ammonia in stripped water , ppmw H 2 S in stripped water , ppmw Total ammonia recovered , tonnes/yr Ammonia quality

1000/227 50 2.0


50 10 39 700

Anhydrous with <5 ppmw HS delivered at 13.8 barg and 40C

Table 2



Bolt- O n SWSPlus-1000 US gpm SWSPlus-1000gpm



Payout from 5 year ‘ B olt- O n’ A bsorber plus smaller SWSPlus



0 1




















7 year standard SWSPlus payout



Life of project, years

Figure 6 Cumulative net revenue vs a 20-year project life


PTQ Q1 2023

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