Continuous Extraction of Black Liquor Salts under Hydrothermal Conditions

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The measured critical temperature of pure water was 373.3 ± 0.2 °C, compared with 373.95 °C from NIST, and the difference was attributed to overcooling.

“The critical temperature of pure water in our measurement was 373.3 ± 0.2 °C, to be compared to the 373.95 °C from the NIST reference database 47 , the difference being caused by an overcooling phenomenon 46 .”

• cites [47] NIST Chemistry WebBook. NIST Standard Reference Database Number 69. http://webbook.nist.gov/chemistry/ (accessed April 6, 2020).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [46] Reimer, J. Biomass Related Salt Solutions at Hydrothermal Conditions. PhD Thesis No. 23104, EPFL, Switzerland, 2015. sourceCould not verify

  Citation 46 is attached to the overcooling explanation; the measured temperature is described as the citing authors’ own result, and the NIST value has a separate citation. The thesis’s Abstract discusses hydrothermal phase transitions, but no passage found attributes a discrepancy in pure water’s measured critical temperature to overcooling (searched: 373.3, 373.95, overcooling, and supercooling). (LLM, conf=0.72)

  Experimental — accuracy not yet measured

May combine two claims.

In HP-DSC heat flow curves, precipitation gives an endothermic peak and liquid-liquid immiscibility gives an endothermic step change.

“An endothermic peak and an endothermic step change are observed in the heat flow curve in the case of precipitation and liquid-liquid immiscibility, respectively 44,45 .”

• cites [44] sourceSupported
• cites [45] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Nickel has a low Ni-Ni2S3 eutectic point at 645°C, explaining the high sensitivity of high-nickel materials to sulfides at atmospheric pressure, while chromium and molybdenum increase corrosion resistance toward sulfides.

“Nickel exhibits a low Ni-Ni2S3 eutectic point at 645°C explaining the high sensitivity of high nickel materials to sulfides at atmospheric pressure 67 , while chromium 68 and molybdenum 69 are known to increase corrosion resistance towards sulfides.”

• cites [67] sourcePartly supported

  The Conclusions (page not available) state that nickel and its alloys corrode very readily in H₂S, supporting the high-sensitivity portion of the claim attributed to citation 67. Our copy does not identify a Ni–Ni₂S₃ eutectic at 645°C or give that eutectic as the explanation. The separate chromium and molybdenum claims carry citations 68 and 69, so they are not judged here. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [68] sourceNot checked — no full text of the source
• cites [69] sourceNot checked — no full text of the source

May combine two claims.

Salt solubility strongly decreases with decreasing water density, and the affected solubility of corrosion products influences corrosion rates.

“Indeed, the solubility of salts strongly decreases with decreasing water density 23 ; the affected solubility of corrosion products will in turn influence corrosion rates 70 .”

• cites [23] sourceSupported
• cites [70] Brunner G., 2014 sourceNot checked — no full text of the source

May combine two claims.

Similar observations were made after gasification of high-sulfur zoo food wastes at 500°C and 300 bars in the same alloy and in supercritical water gasification of black liquor in batch reactors.

“Similar observations were made after gasification tests of high sulfur content zoo food wastes performed at 500°C and 300 bars in a reactor from the same alloy 74 and in the supercritical water gasification of black liquor in batch reactors 75,76 .”

• cites [74] sourceNot checked — no full text of the source
• cites [75] sourcePartly supported

  The Introduction and SCWG Black Liquor section confirm that the paper reports supercritical water gasification of black liquor. But the Reactor Setup and Experimental Procedure describes a pumped feed, an inlet flow rate, and a product stream—not batch reactors. The 500°C, 300-bar zoo-food-waste test is attributed to a different citation in the citing sentence, not to this paper. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [76] sourceNot checked — no full text of the source

Borderline on S4 (based): unclear from the text.

The ratio of potassium to sodium strongly influenced the phase behavior of the salt mixture.

“The potassium-to-sodium ratio was found to strongly impact the phase behavior of the salt mixture.”

May combine two claims.

When K/(K+Na) was at least 0.4, salt separation became steady and up to 96% of salts could be continuously extracted into a concentrated brine effluent.

“At K/(K+Na) ≥ 0.4, a steady salt separation could be reached, enabling the continuous extraction of up to 96 % of the salts in a concentrated brine effluent.”

May combine two claims.

Potassium inhibited salt precipitation and by itself produced a second liquid-like phase.

“Potassium was found to prevent salt precipitation and to lead to the formation of a second liquid-like phase alone.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The K/(K+Na) molar ratio of black liquor ranges from 0.03 to 0.07 and is usually kept below 0.05.

“Note that black liquor K/(K+Na) molar ratio varies from 0.03 to 0.07 (see Table 1), but is usually kept below 0.05.”

May combine two claims.

HP-DSC showed that salt precipitation and a second salt-rich liquid-like phase formed together.

“A high-pressure differential scanning calorimetry study indicated the concomitant precipitation of salt and the formation of a second salt-rich liquidlike phase.”

May combine two claims.

In the model solution test, brine conductivity Cb rose rapidly after 12 min and reached about the feed value after 40 min.

“The conductivity of the brine stream, Cb, started to increase rapidly after 12 min, and reached more or less the same value as the feed after about 40 min”

May combine two claims.

In the model solution test, desalinated stream conductivity Cd began rising 5 min after feed started and stayed below 3 mS cm-1 throughout.

“As shown in Figure 2, the conductivity of the desalinated stream Cd started to increase 5 min after feeding of the model solution to the separator began, and remained lower than 3 mS cm -1 throughout the experiment.”

May combine two claims.

In the black liquor test, Cd increased after 8 min of feeding, and Cb rose rapidly starting 15 min after feed start.

“Cd shows an increase after 8 min of feeding black liquor, followed by the rapid rise of Cb starting 15 min after the start of BL feed.”

May combine two claims.

For K/(K+Na)≤0.2, sulfur recovery decreased with time on stream and a plug formed after 138 minutes at 0.1 and 245 minutes at 0.2.

“However, for K/(K+Na) ≤ 0.2, the S recovery decreased with time on stream, which was followed by the formation of a plug after 138 and 245 minutes at K/(K+Na) ratios of 0.1 and 0.2, respectively.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The brine outlet was gas-free, while strong gas formation, not analyzed, occurred in the desalinated stream.

“The brine outlet stream was free of gases, while a strong gas formation (not analyzed) was observed in the desalinated stream.”

May combine two claims.

At K/(K+Na)=0.1, brine conductivity began to decrease after about 25 minutes of steady operation while desalinated stream conductivity remained stable.

“For a molar ratio K/(K+Na) = 0.1, the conductivity in the brine Cb started to decrease gradually after about 25 min of steady operation, while Cd remained rather stable.”

May combine two claims.

At K/(K+Na)=0.2, the same decreasing trend appeared, but the high brine conductivity plateau lasted about 85 minutes.

“The same trend also appeared in the case of K/(K+Na) = 0.2, but the high Cb plateau lasted ca.85 min.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

Pure NaOH forms a liquid brine in supercritical water and is a type 1 salt, as does NaHS.

“despite the fact that pure NaOH forms a liquid brine in supercritical water (type 1 salt), just as NaHS (see section 3.2).”

May combine two claims.

In the model solution test, recoveries of fed sodium, carbon, sulfide, and total sulfur in the brine and desalinated streams were 24±2%, 25±2%, 26±4%, and 25±15%, respectively, with most minerals in the brine.

“As a result of the salt deposition in the vessel, the quantity of fed sodium, carbon, sulfide and total sulfur that were recovered in the brine and the desalinated streams were 24±2%, 25±2%, 26±4% and 25±15%, respectively (see Table S1), the majority of the minerals being recovered in the brine.”

May combine two claims.

Experiments at K/(K+Na)=0.4 and 0.75 were stopped after 5 h and 4 h, respectively, with no salt plug and no effluent conductivity change.

“Experiments at K/(K+Na) = 0.4 and 0.75 were stopped regularly after 5 h and 4 h, respectively (no salt plug formed, no change in effluents conductivity).”

May combine two claims.

During the high brine conductivity plateau at K/(K+Na)=0.1-0.2, recoveries were 75-92% for sodium, 93-104% for potassium, 78-83% for carbonate, 98-104% for sulfide, and 84-95% for sulfur.

“The quantity of sodium, potassium, carbonate, sulfide, and sulfur recovered in the brine and desalinated streams for K/(K+Na) = 0.1-0.2molar ratios during the high brine conductivity plateau are 75-92 %, 93-104 %, 78-83 %, 98-104 % and 84-95 %, respectively (see Figure 5 and SI).”

May combine two claims.

The pH values agree with conductivity measurements: the desalinated stream had pH 10-10.5, while nearly all brine samples had pH 13.5-14 due to increased black liquor salt concentration.

“The pH values are consistent with the conductivity measurements, the desalinated stream having pH = 10-10.5,while almost all of the brine samples being at a pH of 13.5-14, resulting from the increased concentration of BL salts.”

May combine two claims.

At K/(K+Na)≥0.25, salt recovery in the brine was >96% for sodium, >94% for potassium, 87-100% for carbonate, 87-99% for sulfide, 87-94% for total sulfur, and 78-100% for sulfate, always above 90% for all salts considered.

“Overall, the salt recovery in the brine was >96 %, >94 %, 87-100 %, 87-99 % , 87-94 % for sodium, potassium, carbonate, sulfide, and total sulfur (78-100 % for sulfate), respectively, at K/(K+Na) ≥ 0.25, and was always greater than 90%, all salts considered.”

May combine two claims.

For K/(K+Na)=0.1, 0.2, and 0.4, the desalinated stream conductivity increased slightly but stayed below 1 mS/cm, while the brine conductivity rose to more than twice the feed conductivity for K/(K+Na)≥0.1.

“In all the three cases, the conductivity of the desalinated stream Cd increased slightly after starting feeding model salt solutions but remained lower than 1 mS cm -1 as observed with K/(K+Na) = 0, while the brine conductivity Cb increased to more than twice that of the feed with K/(K+Na) ≥ 0.1.”

May combine two claims.

Organic carbon in the brine cannot be avoided, and with continuous brine extraction the brine carbon concentration is typically comparable to the feed.

“The presence of organic carbon in the brine cannot be avoided, and as a continuous flow of brine is extracted, a carbon concentration comparable to that of the feed is typically found in the brine.”

May combine two claims.

An intermediate period was observed for all model solutions with K/(K+Na)≤0.2, and a lower potassium ratio gave a shorter intermediate plateau.

“This intermediate period was observed with all model solutions with K/(K+Na) ≤ 0.2: the lower the potassium ratio was, the shorter that intermediate plateau lasted.”

May combine two claims.

After about 30 min in the black liquor test, Cd increased to 35 mS cm-1 and began to fluctuate.

“After about 30 min, the conductivity of the desalinated stream Cd increased to 35 mS cm -1 and started to fluctuate.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The black liquor desalinated stream was light brown with suspended black solids and an oily phase, while the brine was dark brown, similar to black liquor but more viscous.

“The desalinated stream produced was light brown with a small quantity of suspended black solids and an oily phase, while the brine stream was dark brown, similar to black liquor itself but more viscous.”

May combine two claims.

In the corrosion tests, test A caused the most severe corrosion, with 3-4 mg of iron leaching over the 3-hour test.

“Overall, the test that led to the most severe corrosion was the first (test A), with 3 to 4 mg of iron leaching over the whole test (3 h long).”

May combine two claims.

The decrease becomes more pronounced near the critical point of water, reaching minima at 370.3°C for NaHS-NaOH and 372.6°C for NaHS.

“This decrease becomes more pronounced when approaching the critical point of water (374°C), reaching a minimum at 370.3°C and 372.6°C for NaHS-NaOH and NaHS solutions, respectively.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Preliminary HP-DSC tests at higher concentration ended in leakage of the sealed DSC crucibles.

“A few preliminary tests at higher concentration ended up in leakage of the sealed DSC crucibles.”

May combine two claims.

During the first experiment, both effluents turned opaque and dark green for about 15 minutes, indicating high salt concentration redissolving in a colder or denser fluid, probably from corrosion or redissolution of corrosion products.

“During the first experiment (Exp.B), both effluents turned opaque and dark green for about 15 minutes, indicating high concentration of salts redissolving in a colder/more dense fluid probably as the result of corrosion or of the redissolution of corrosion products (inorganic content: 22 and 112 g L -1 in the desalinated and brine streams).”

May combine two claims.

The O2/S molar ratios were 0.11 for NaHS and 0.16 for NaHS:NaOH solutions.

“The O2/S molar ratios for the NaHS and the NaHS:NaOH solutions were 0.11 and 0.16, respectively.”

May combine two claims. The quote only partly states this claim.

The homogenization temperatures are 375.8°C and 379.9°C for NaHS-NaOH and NaHS, respectively.

“The temperatures of homogenization are 375.8°Cand 379.9°C, respectively (see method in part 2.2).”

May combine two claims.

During sulfide-containing model solution tests at steady state, the desalinated stream was typically uncolored while the brine effluent was slightly greenish/brownish, indicating some corrosion of the brine tubing.

“During the tests performed with model solutions containing sulfide, at steady state, the desalinated stream was typically uncolored while the brine effluent was colored to a slight greenish/brownish, indicating some corrosion of the brine tubing.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The thermocouple measuring the desalinated stream temperature at the separator exit broke at the end of the third test.

“The thermocouple measuring the temperature of the desalinated stream at the exit of the separator (T3 in Fig. 1) broke at the end of the third test.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The sheathed type K thermocouple at the top of the salt separation vessel, the hottest point at 430-440°C, broke after the second test.

“The sheathed thermocouple (type K) placed at the top of the salt separation vessel (T1 in Fig. 1), the hottest point of the testing unit (430-440°C), broke after the second test.”

May combine two claims.

At K/(K+Na)=0.75, neither an endothermic step nor an endothermic peak was observed.

“With further addition of potassium (K/(K+Na) = 0.75), neither an endothermic step nor an endothermic peak could be observed.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The same phenomenon is also observed for pure water.

“This phenomenon is as well observed for pure water (see Figure S1).”

May combine two claims.

For experiment B, ICP-OES showed 11 ppm Fe, 27 ppm Al, and 0.7 ppm Cr in the brine, while the desalinated stream had 24 ppm Fe and 31 ppm Al, with Ni below detection.

“For experiment B, elemental analysis (ICP-OES) showed 11 ppm Fe, 27 ppm Al and 0.7 ppm Cr in the brine stream, while the desalinated stream had 24 ppm Fe and 31 ppm Al (Ni below detection limit).”

May combine two claims.

Increasing the potassium-to-sodium molar ratio alleviated and eventually prevented salt accumulation in the separation vessel.

“By increasing the potassium to sodium molar ratio, the salt accumulation in the separation vessel could be alleviated and eventually prevented.”

May combine two claims.

The effluent composition indicated that sulfides and/or carbonates underwent hydrolysis, yielding CO2 and H2S that ended up in the desalinated stream and deprotonated back when cooled, buffering effluent pH at 10.5.

“The composition of the effluents indicated that sulfides and/or carbonates underwent hydrolysis, yielding CO2 and H2S ending up in the desalinated stream, that deprotonate back when cooled down (effluent pH buffered at 10.5).”

May combine two claims.

When the K/Na ratio increased to 0.4, no endothermic peak indicative of precipitation was observed, while the signal linked to liquid-liquid immiscibility at 373.4°C was more pronounced.

“When the K/Na ratio increased to 0.4, no endothermic peak indicative of precipitation was observed, while the signal linked to liquid-liquid immiscibility (G-L → G-L 1 -L 2 ) at 373.4°C was more pronounced.”

May combine two claims.

Long-term efficient salt recovery was achieved only at a K/(K+Na) molar ratio of 0.4, without apparent salt accumulation in the separation vessel.

“A long-term efficient salt recovery could only be achieved with a K/(K+Na) molar ratio of 0.4 without apparent accumulation of salts in the separation vessel, the minimum K/(K+Na) for long-term efficient salt recovery being somewhere between 0.25 and 0.4.”

May combine two claims.

An increase in K/Na ratio suppresses precipitation at K/(K+Na) = 0.4, allowing continuous salt extraction.

“An increase in K/Na ratio was found to suppress precipitation (K/(K+Na) = 0.4), hence allowing continuous salt extraction.”

May combine two claims.

Fouling can be prevented by increasing the K/(K+Na) molar ratio to 0.4 or more, at which black liquor salts can be extracted from the main stream and concentrated into a brine with total salt recovery up to 96%.

“Fouling can be prevented by increasing the K/(K+Na) molar ratio to 0.4 or more, at which black liquor salts can be extracted from the main stream and concentrated into a brine with a total salt recovery reaching up to 96%.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Supercritical water treatment of weak black liquor can be more thermally efficient than traditional technologies, with system efficiencies of 83% at 450°C and 80% at 600°C.

“The latest research showed that supercritical water treatment of weak black liquor could be thermally more efficient than traditional technologies, having a system efficiency of 83% and 80% at 450°C and 600°C operating temperature, respectively 12 .”

• cites [12] sourceNot checked — no full text of the source

May combine two claims.

At 150-300 bars and 250-600°C, sulfate reduction to sulfide is favored, which suggests hydrothermal processes may permit recovery of cooking chemicals.

“In addition, the reduction of sulfate to sulfide is also favored under the reaction conditions used (150-300 bars, 250-600°C) indicating that hydrothermal processes might as well allow cooking chemicals recovery [15][16][17] .”

• cites [15][16][17]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The main inorganic chemicals in black liquor are Na2CO3, Na2SO4, NaOH, NaHS, and Na2S2O3, with broad concentration ranges on a weak black liquor weight basis.

“The main inorganic chemicals in black liquor are Na2CO3, Na2SO4, NaOH, NaHS (often referred to as Na2S) and Na2S2O3 in rather broad concentration ranges, that are 5.8-10.1 wt%, 1.6-9.4wt%, 1.1-5.2wt%, 3.1-7.3wt% and 2.5 wt% on the weak black liquor weight basis, respectively.[33][34][35]”

• cites [33][34][35]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

A pure water sample measured three times gave a standard deviation of 0.2°C, which was sufficient to validate the method.

“A pure water sample was first measured three times in order to evaluate the repeatability of the analysis.A standard deviation of 0.2°C was observed (see Figure S1) which is sufficient to validate the method.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Type 1 salts have a positive temperature coefficient of solubility and form a dense salt-rich liquid-like phase in equilibrium with a salt-depleted vapor-like phase.

“Type 1 salts are characterized by a positive temperature coefficient of solubility (t.c.s.), which leads to the formation of a dense salt-rich liquid-like phase in equilibrium with a salt-depleted vapor-like phase.”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source

May combine two claims.

Even if the phase behavior of each individual salt is known, that of a salt mixture cannot be predicted; a mixture of two type 2 salts may behave as type 1.

“Even when the phase behavior of all the respective individual salts is known, it is impossible to predict it for a mixture of salts.Indeed, a mix of two type 2 salts may behave as type 1 32,40,41 .”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source
• cites [40] sourceNot checked — no full text of the source
• cites [41] sourceNot checked — no full text of the source

May combine two claims.

Some inorganic compounds in black liquor can form low-eutectic salt mixtures in recovery boilers, and the resulting molten salts cause fouling and may accelerate equipment corrosion.

“In recovery boilers, some inorganic compounds present in black liquor can form salt mixtures with low eutectic point, the molten salts formed causing fouling and potentially accelerating corrosion of the equipment 8 .”

• cites [8] Tran H., 1997Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In supercritical water, organic compounds are highly soluble while salt solubility is greatly reduced.

“This affects the solvent properties of supercritical water, in which organics are very soluble while solubility of salts is severely reduced [21][22][23] .”

• cites [21][22][23]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

Salt phase behavior under hydrothermal conditions is classified mainly into type 1 and type 2 by Valyashko.

“The phase behavior of salts under hydrothermal conditions has been classified mainly as type 1 and type 2 by Valyashko 32 .”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source

May combine two claims.

The separator temperature gradient creates a low-solubility zone in the top half, while the cooler subcritical bottom re-dissolves solids from the upper part, preventing clogging and improving brine recovery.

“The concept behind this temperature gradient is to create a low solubility zone at the top half in the separator, while the lower temperature at the bottom part (sub-critical) helps to re-dissolve the solids that might precipitate from the upper part, thus preventing clogging and improving the recovery efficiency in the brine.28,29”

• cites [28] sourceNot checked — no full text of the source
• cites [29] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Type 1d is a further classification for solutions that show liquid-liquid immiscibility.

“Further classification can be made, defining if the solution exhibits liquid-liquid immiscibility (type 1d) 32 .”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source

May combine two claims.

Under hydrothermal conditions, inorganic compounds in black liquor tend to precipitate and can foul heat exchangers and block pipes.

“While organic matter is transformed to fuels under hydrothermal conditions, the inorganic compounds present are prone to precipitation that can foul heat exchangers and clog pipes [18][19][20] .”

• cites [18][19][20]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Sodium carbonate and sodium sulfate are classified as type 2, whereas sodium hydroxide is type 1.

“Sodium carbonate and sodium sulfate have been classified as type 2 while sodium hydroxide is type 1 32 .”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Type 2 salts show a change in temperature coefficient of solubility that causes a sharp solubility decrease at a certain temperature, producing a solid phase and a salt-depleted supercritical fluid phase.

“The type 2 salts are characterized by a change in t.c.s. that leads to a dramatic drop of the solubility at a certain temperature resulting in the formation of a solid phase (precipitation) and a salt-depleted supercritical fluid phase.”

• cites [32] Valyashko V. M., 2008 sourceNot checked — no full text of the source

May combine two claims.

Reported decomposition of NH4+ into NH3 in supercritical water and of carbonate and bicarbonate into carbon dioxide supports formation of these neutral compounds; KHCO3 decomposes more readily than K2CO3.

“The formation of these neutral compounds is indeed supported by the reported decomposition of NH4 + into NH3 in supercritical water 57,58 and carbonate and bicarbonate into carbon dioxide 59 , KHCO3 being found to decompose more readily than K2CO3.”

• cites [57] sourceNot checked — no full text of the source
• cites [58] sourceNot checked — no full text of the source
• cites [59] sourceNot checked — no full text of the source

May combine two claims.

Carbonate and sulfate mass balances were not closed in all experiments with K/(K+Na)≥0.25, possibly due to minor salt accumulation in the rig.

“Note, however, that the carbonate and sulfate mass balances are not closed in all experiments with K/(K+Na) ≥ 0.25, which might be explained by some minor salt accumulation in the rig.”

May combine two claims.

Conductivity profiles during cooling under DI water indicated salt release from the separator, confirming salt buildup in the vessel.

“The conductivity profiles obtained when cooling down the setup under DI water (not shown) is indicative of a release of salts from the salt separator, confirming a buildup of salts within the vessel.”

May combine two claims.

Because sulfate is a very weak base, only hydroxide can explain the high pH of the desalinated stream.

“Sulfate being a very weak base, only the presence of hydroxide can explain the high pH of the desalinated stream (pH ≈ 10.5).”

May combine two claims.

After switching to DI water and lowering separator temperature, desalinated stream conductivity increased, consistent with redissolution and flushing of accumulated salts.

“The conductivity, i.e. a proxy for the total salt concentration, started to increase in the desalinated stream after switching to DI water and decreasing the temperature of the salt separator, which is in line with a redissolution and flushing out of the salts accumulated in the vessel.”

• AssumptionThe authors state this as an assumption: Salts accumulated in the vessel throughout the model solution experiment.

Probably not a substantial claim: may not pass S3 (load-bearing).

In similar salt separation tests with carbonate, bicarbonate, or ammonium, formation of stable SCW-soluble CO2 and NH3 was hypothesized to explain unexpected ionic ratios in desalinated streams.

“Similar observations were made during salt separation tests performed with carbonate, bicarbonate or ammonium where the formation of stable and SCW-soluble CO2 and NH3 were hypothesized to explain unexpected ionic ratios in desalinated streams 28,41 .”

• cites [28] sourceNot checked — no full text of the source
• cites [41] sourceNot checked — no full text of the source

May combine two claims.

The solubilities of Na2SO4, Na2CO3, K2SO4, and KOH are 0.2, 1, 4, and 12 mmole Na/K/L at a water density of 160 kg/m3 reached at 290 bars and an expected temperature of 435°C.

“This is to be compared with the solubility of Na2SO4 54 , Na2CO3 54 , K2SO4 55 , KOH 56 of 0.2, 1, 4 and 12 mmoleNa/K L -1 at a water density of 160 kg m -3 reached at 290 bars and an expected temperature of 435°C.”

• cites [54] sourceNot checked — no full text of the source
• cites [55] sourceNot checked — no full text of the source
• cites [56] sourceNot checked — no full text of the source

May combine two claims.

Because HCO3- is a much stronger acid than hydrosulfide, the solution pH would be buffered to about 10.3, matching the measured effluent pH of 10.5.

“The latter being a much stronger acid (pKa 10.3 60 ) than the hydrosulfide (pKa supposedly above 14 39,61 ), the pH of the solution would hence be buffered to ca. 10.3, in phase with the pH of this effluent systematically being measured at 10.5.”

• cites [60] Williams M., 2013Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [39] sourceNot checked — no full text of the source
• cites [61] Dittmer D. C., 2001 sourceNot checked — no full text of the source

May combine two claims.

The H2S and CO2 formed, being miscible in supercritical water, would preferentially leave the separation vessel in the desalinated stream, explaining the low M/(C+S) ratio.

“The H2S and CO2 formed, miscible in supercritical water, would preferentially flow out of the separation vessel in the desalinated stream, thus explaining the low M/(C+S) molar ratio observed.”

May combine two claims.

The brine conductivity level indicates initial efficient salt separation and salt concentration in the continuously extracted brine during the first 20 minutes of steady state.

“This Cb level indicates an initial efficient salt separation and a concentration of the salts in the continuously extracted brine during the first 20 min of steady state.”

May combine two claims.

Replacing Na by K shifts the salt mixture phase diagram from pseudo-type 2 to pseudo-type 1, forming a dense liquid phase instead of a salt precipitate and allowing continuous extraction of a salt-enriched stream.

“The replacement of Na by K shifts the phase diagram of the salt mixture from pseudo-type 2 to pseudo-type 1, forming a dense liquid phase instead of a salt precipitate, allowing a continuous extraction of a salt-enriched stream.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The absence of sulfide is expected to affect the overall salt mixture phase behavior, but increasing K/Na is expected to have a stronger impact; NaHS is type 1 and KHS is expected to be type 1 as well.

“The absence of sulfide salt is of course expected to affect the overall salt mixture phase behavior, but the increase of the K/Na ratio is expected to have a stronger impact on the global phase behavior, sodium hydrosulfide being a type 1 salt, potassium hydrosulfide is expected to be type 1 as well (see section 3.1.2).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Corrosion of stainless steel can be caused by sulfides, and the sulfidation rate of most metals is typically high at atmospheric pressure and high temperature.

“Corrosion of stainless steel can be caused by sulfides 65,66 , and the sulfidation rate of most metals is typically high at atmospheric pressure and high temperature.”

• cites [65] sourceNot checked — no full text of the source
• cites [66] Vakkilainen E. K., 2017 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The source of aluminum remains unclear, with one possible source being corroded type K thermocouple sheaths.

“The source of aluminum remains unclear, one possible source being the corroded type K thermocouple sheaths.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Nickel improves corrosion behavior of steels in alkaline and oxidative supercritical water, but alloy stability and corrosion mechanism under alkaline reducing conditions remain unclear.

“While nickel improves corrosion behavior of steels in alkaline and oxidative SCW environment 70 , the stability of alloys and the corrosion mechanism under alkaline and reducing conditions remain unclear.”

• cites [70] Brunner G., 2014 sourceNot checked — no full text of the source

May combine two claims.

These conditions allow continuous and stable salt extraction, as evidenced by K/(K+Na)=0.4 showing constant brine conductivity for 5 hours.

“These conditions allow a continuous and stable extraction of salts from the main stream as evidenced for instance for K/(K+Na) = 0.4, showing a constant Cb for 5 h (Figure 3).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The additional minor endothermic peak for NaHS at 376.7°C could be linked to a chemical reaction.

“The additional signal for NaHS at 376.7°C is a minor peak with a positive Δcv (endothermic), which could be linked to a chemical reaction taking place.”

May combine two claims.

Because the crucible air was not flushed, oxygen could partially oxidize sulfide to S(0), which hydrolyzes in supercritical water to H2S and H2SO4, possibly causing the peak.

“The air contained in the crucible was not flushed, and the oxygen can lead to a partial oxidation of sulfide to S(0), that in turn hydrolyses in supercritical water to H2S and H2SO4 64 , which may be the cause of this peak.”

• cites [64] sourceNot checked — no full text of the source

May combine two claims.

Although sulfide was missing from the tested model solution, the HP-DSC study supports the salt separation efficiency and the hypothesis that both a solid and a liquid brine form under supercritical conditions.

“Although sulfide is missing in the model solution tested, the HP-DSC study supports the salt separation efficiency on Salsan-II and the hypothesis made to describe the results obtained, that is, the formation of both a solid and of a liquid brine under supercritical conditions (see Figure 7).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The peak could also be related to an endothermic signal from sodium sulfate precipitation.

“This peak could also be related to the endothermic signal resulting from sodium sulfate (type 2) precipitation.”

May combine two claims.

Sulfate can be reduced by organic compounds to sulfides under hydrothermal conditions, which might significantly increase sulfide concentration during hydrothermal processing of black liquor.

“It is important to note here that sulfate can be reduced by organic compounds to sulfides under hydrothermal conditions (thermochemical sulfate reduction) [78][79][80] , which might significantly increase sulfide concentration during hydrothermal processing of a black liquor.”

• cites [78][79][80]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The exothermic step at 388.6°C representing formation of a salt-depleted supercritical fluid phase is more gradual than at lower K ratio, consistent with absence of clear liquid-liquid immiscibility.

“The exothermic step signal at 388.6°C representing the formation of salt depleted supercritical fluid phase is more gradual than for the lower K ratio, in phase with the absence of a clear liquid-liquid immiscibility.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Viereck et al. compared experimental results with fluid flow-field and Stokes numbers for 80 μm particles simulated by computational fluid dynamics.

“Viereck et al. compared experimental results with fluid flow-field and Stokes numbers (particles of 80 µm) simulated by computational fluid dynamics 62 .”

• cites [62] Viereck, S. Experimental and Numerical Investigations of Salt Separation from Biomass at Hydrothermal Conditions Exploiting Aqueous Solutions of Sodium Sulfate and Pure Water as Model Systems. PhD Thesis No. 24832, ETH Zürich, Switzerland, 2018.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The green color is likely due to colloidal MFeS2 (M=Na,K), believed to cause the color of green liquor in the Kraft process.

“The green color is likely due to the presence of colloidal MFeS2 (M = Na, K) believed to be at the origin of the color of green liquor in the Kraft process 81 .”

• cites [81] sourceNot checked — no full text of the source

May combine two claims.

If the flow and/or composition of the type 1 salt brine are in the right range, no solids form or they do not accumulate on the vessel wall.

“On the other hand, if the flow and/or the composition of the salt 1 brine are in the right range, no solids are formed or they do not succeed to accumulate on the vessel's wall.”

May combine two claims.

With time, type 2 salts may deposit and accumulate at vessel walls, act as nucleation sites after reaching a critical size, and cause severe salt accumulation eventually blocking the separation vessel.

“With time, type 2 salts may deposit and accumulate at the vessel walls, and these salt deposits may act as nucleation sites after reaching a critical size, from which severe salt accumulation occurs eventually ending up with the full blockage of the separation vessel.”

May combine two claims.

At worst, 5.6% of sulfide for NaHS and 7.8% for NaHS:NaOH could have reacted to sulfate.

“At worst, 5.6% and 7.8% of sulfide could have reacted to sulfate for NaHS and NaHS:NaOH, respectively.”

Probably not a substantial claim: may not pass S3 (load-bearing).

This is consistent with leakage of the single-use Incoloy crucibles in the HP-DSC tests when measuring a 1 wt% sulfide solution under supercritical conditions with a 0.1 K/min ramp.

“This is in phase with the leakage of the single-use Incoloy crucibles used for the HP-DSC tests described above when measuring a 1 wt% sulfide solution at supercritical conditions using 0.1 K min -1 temperature ramp.”

May combine two claims.

Analysis of solid deposits after hydrothermal gasification of black liquor in a 316SS flow reactor indicated preferential loss of chromium and especially nickel, while iron was barely affected.

“The analysis of solid deposits recovered after hydrothermal gasification of black liquor in a 316SS flow reactor indicated a preferential loss of chromium and more importantly nickel, while iron was barely affected 77 .”

• cites [77] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

This sulfate corrosion phenomenon should be significantly altered by the presence of sulfides in black liquor and the reducing conditions of hydrothermal black liquor processing.

“This phenomenon should be significantly altered by the presence of sulfides in black liquor and the reducing conditions of hydrothermal processing of BL.”

May combine two claims.

An endothermic step at 375.1°C is assigned to liquid-liquid immiscibility, with a salt-depleted gas-like liquid and a salt-enriched liquid.

“This is followed by an endothermic step at 375.1°C that is assigned to a liquid-liquid immiscibility phenomenon (G-L-S → G-L 1 -L 2 -S), the two liquids being a salt depleted gas-like liquid (L 1 ) and a salt-enriched liquid (L 2 ).”

May combine two claims.

The brine redissolves or disperses solids accumulating on the separator walls, slowing salt plug formation and allowing temporary efficient extraction.

“This supports the hypothesis that the brine redissolves or disperses the solids accumulating on the separator walls, slowing down the formation of a salt plug and allowing a temporary efficient extraction.”

May combine two claims.

The precipitation caused severe fouling of the salt separator vessel and ultimately plugged it.

“This precipitation occured without segregation of any salts, leading to severe fouling of the salt separator vessel and its ultimate plugging.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Model solutions were prepared and maintained under O2-free atmosphere during the test to prevent sulfide oxidation.

“Note that the model solutions are prepared and maintained under O2-free atmosphere during the test to prevent sulfide oxidation.”