Process Simulation of Sulfuric Acid Recovery by Azeotropic Distillation: Vapor–Liquid Equilibria and Thermodynamic Modeling
Bibliographic record
Abstract
For development of the new process for the recovery of dilute sulfuric acid by azeotropic distillation proposed in our earlier publication [Li et al., Ind. Eng. Chem. Res., 2013, 52, 3481–3489], in this paper, the vapor–liquid equilibria (VLE) for the FeSO 4 + H 2 O and H 2 SO 4 + FeSO 4 + H 2 O systems were first determined by the quasi-static ebulliometric method. The azeotropic temperatures of the H 2 SO 4 + H 2 O + entrainer (cyclohexane and octane) systems were also measured. The corresponding electrolyte nonrandom two-liquid interaction parameters were obtained by regressing the experimental data with a maximum average absolute deviation of boiling points of 0.83 K. The model with newly obtained parameters was verified by comparing its prediction with the experimental azeotropic temperature for the H 2 SO 4 + FeSO 4 + H 2 O + C 6 H 12 quaternary system. The temperature and sulfuric acid concentration ranges of the study were 305.9–396.9 K and 0–86.1 wt %, respectively. Following from the experimental results, semicontinuous distillation experiments for the sulfuric acid recovery were performed with cyclohexane as the entrainer. Equipped with the new parameters, Aspen Plus was adopted to carry out the process simulation for the recovery of dilute sulfuric acid by azeotropic distillation. The simulation results show that when cyclohexane was employed as the entrainer, the dilute sulfuric acid can be concentrated to 68% by a packed column containing 4 theoretical stages and with a reboiler temperature of only 361 K.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".