A kind of gas sweetening agent and preparation method thereof
Technical field
The present invention relates to a kind of gas sweetening agent, be specifically related to a kind of reproducible sodium radio-phosphate,P-32 solution that has added compound surfactant.Can be widely used in the gas sweetening decarburization fields such as selexol process, flue gas desulfurization.
Background technology
The energy overwhelming majority that mankind nowadays is used is non-renewable coal, oil and natural gas.Present domestic sulfur Gas Fields (mass fraction of sulphur be 2% one 4%) gas output accounts for 60% of national gas output, and most sulfide all are the impurity that is harmful to for natural gas, hydrogen sulfide particularly, not only the visual plants such as storage tank and pipeline are caused heavy corrosion, and serious harm the Nature and the mankind's is healthy.To fundamentally address these problems, just must consider to remove the hydrogen sulfide in the natural gas.The industrial desulfurizer of widely using is tower structure, and doctor solution is chemical desulfurization liquid.Consider that from economic angle selected chemical desulfurization liquid should possess the performance of regeneration, mainly contains hydramine, carbonate, natrium citricum, phosphate, ammoniacal liquor, seawater etc.Phosphate belongs to Multiple Weak Acid salt, and its aqueous solution has certain cushioning effect, and is higher to the absorptive capacity of acid gas, and have certain non-oxidizability, if control concentration of aqueous solution well, can suppress well the generation of thiosulfate and other impurity.So phosphate has good application prospect at desulfuration field.But the solubility of phosphate in water is not very high, and the simple aqueous phosphatic desulfuration efficiency that utilizes is not very high, so can utilize some activating agents of interpolation to improve its desulfuration efficiency.And surfactant can reduce the surface tension of solution, can produce a large amount of minute bubbles when gas enters in the solution, thereby has increased the gas-liquid contact area, is conducive to the absorption of hydrogen sulfide.
The aobvious alkalescence of aqueous phosphatic, selected surface-active should have alkali resistance, salt tolerance.Then require this surfactant to have high foaming characteristic and stability in order to produce a large amount of minute bubbles.Anion-nonionic type surfactant combines the many merits of ionic and nonionic surface active agent, such as good dissolubility and stability, good salt-resistant temperature performance, good compatibility and efficient foaming capacity etc.Need add lastingly a kind of foam stabilizer for the foam that can make generation in addition and anion-nonionic type surfactant is used.
Why adopt the anion-nonionic surfactant mainly to be because the anti-salt action of nonionic surface active agent is better, and foaming capacity is slightly poor, the anionic surfactant foaming capacity is good, but its anti-salt action is relatively poor.And when both form binary mixture, given full play to its advantage separately, overcome the deficiency of the two.
Summary of the invention
The objective of the invention is provides the efficient natural gas desulfurizer for the deficiencies in the prior art.For achieving the above object, the present invention adopts following technical scheme:
The present invention utilizes surfactant and acidic aqueous solution to keep the pH value of doctor solution, increases absorptive capacity to hydrogen sulfide with this.
A kind of natural gas desulfurizing agent of the present invention, its composition and formula rate are:
Salt: 3 ~ 23%(wt);
Foam stabilizer: 0.05 ~ 0.1%(wt);
Surfactant: its concentration that accounts for total solution is 10 * 10
-5~ 25 * 10
-5Mol/L;
The acidic aqueous solution amount so that the pH value of doctor solution be as the criterion 8.5 ~ 9.0.
Surplus is water.
Wherein said salt is sodium phosphate dodecahydrate (Na
3PO
412H
2O);
Wherein said foam stabilizer is lauryl alcohol;
Wherein said surfactant is the compound of anion surfactant and non-ionic surface active agent, and wherein anion surfactant is a kind of of lauryl sodium sulfate (SDS), α-alkene sulfonic acid sodium (AOS) etc.; Non-ionic surface active agent is APG (APG08-10).Anion surfactant and non-ionic surface active agent respectively account for 50%.
Wherein said acid is phosphoric acid.
The preparation method of described a kind of natural gas desulfurizing agent, carry out according to following step: first that sodium phosphate is soluble in water under 25 ~ 30 ℃ according to aforementioned proportion, add foam stabilizer and surfactant, stirred about 20 ~ 30 minutes, and be adjusted to needed pH value with acidic aqueous solution.
The invention has the advantages that:
(1) applied range.Do not have toxicity, renewable performance is good, can be in field extensive uses such as selexol process, flue gas desulfurization decarburizations.
(2) desulfurized effect is good.Composite desulfurizing agent effectively reduces surface tension.By surface tension test, composite desulfurizing agent reduces by 15 ~ 33% than single component sodium carbonate surface tension under same temperature conditions, makes gas form easily minute bubbles, has effectively increased the gas liquid ratio surface area, improved mass transfer rate, desulfuration efficiency is reached more than 95%.
(3) cost is low, good economy performance.Active desulfurizing agent cost of the present invention is low, and consumption is few, and acidity load is high, and desulfuration efficiency is high and power consumption is few.Hydrogen sulfide is desorbed, can realize recycling.The existence of surfactant can also be removed dirt effectively, prevents the accumulation of pollutant.
Description of drawings
Fig. 1 is the selexol process process device figure
1. gas cylinder; 2. pressure gauge; 3. flowmeter; 4. gas distributor; 5. doctor solution case; 6. pump; 7. desulfurizing tower; 8. chromatograph; 9. thermometer.
The specific embodiment
Embodiment 1
The quality percentage composition that accounts for solution by sodium phosphate dodecahydrate is 3.0%(300g), lauryl alcohol is 0.05%(5.2g), water (10000g), the concentration of anionic and non-ionic surface active agent APG is 5 * 10
-5Mol/L(mol).According to aforementioned proportion, first that sodium phosphate is soluble in water under 25 ~ 30 ℃, add foam stabilizer and surfactant, stirred afterwards 20 ~ 30 minutes, add phosphate aqueous solution and make its pH value 8.5 ~ 9.0, the configuration doctor solution.
Embodiment 2
The quality percentage composition that accounts for solution by sodium phosphate dodecahydrate is 23.0%(3000g), lauryl alcohol is 0.05%(6.5g), water (10000g), the concentration of anionic and non-ionic surface active agent APG is 5 * 10
-5Mol/L(mol).According to aforementioned proportion, first that sodium phosphate is soluble in water under 25 ~ 30 ℃, add foam stabilizer and surfactant, stirred 20 ~ 30 minutes, add phosphate aqueous solution and make its pH value 8.5 ~ 9.0, the configuration doctor solution.
Embodiment 3
The quality percentage composition that accounts for solution by sodium phosphate dodecahydrate is 23.0%(3000g), lauryl alcohol is 0.1%(13g), water (10000g), the concentration of anionic and non-ionic surface active agent APG is 12.5 * 10
-5Mol/L(mol).According to aforementioned proportion, first that sodium phosphate is soluble in water under 25 ~ 30 ℃, add foam stabilizer and surfactant, stirred 20 ~ 30 minutes, add phosphate aqueous solution and make its pH value 8.5 ~ 9.0, the configuration doctor solution.
Embodiment 4
The quality percentage composition that accounts for solution by sodium phosphate dodecahydrate is 3.0%(300g), lauryl alcohol is 0.05%(5.2g), water (10000g), the concentration of anion surfactant α-alkene sulfonic acid sodium and non-ionic surface active agent APG is 5 * 10
-5Mol/L(mol).According to aforementioned proportion, first that sodium phosphate is soluble in water under 25 ~ 30 ℃, add foam stabilizer and surfactant, stirred 20 ~ 30 minutes, add phosphate aqueous solution and make its pH value 8.5 ~ 9.0, the configuration doctor solution.
The desulfurization of embodiment 5 natural gas desulfurizing agents
According to selexol process process chart as shown in Figure 1, sulfide hydrogen be 5% natural gas from gas cylinder 1 through pressure gauge 2 and through flowmeter 3 metered flows, flow set is 1 m
3/ h, 3 m
3/ h, 5 m
3/ h, 7 m
3/ h.Enter desulfurizing tower 7 after the gas dosing, the diameter 100mm of desulfurizing tower 7, high 1500mm.The gas distributor 4 of installing in the desulfurizing tower bottom can form bubble with gas.In the doctor solution case 5 electric heater is housed, can changes fluid temperature, design temperature is 23 ℃ in the present embodiment, is drawn the doctor solution temperature that enters in the tower by thermometer 9.Circulate by pump 6, the hydrogen sulfide in the gas is desulfurized liquid and absorbs in desulfurizing tower 7.Purified gas outflow desulfurizing tower 7 enters chromatograph 8 and analyzes.Move continuously under these conditions 30 minutes, desulfuration efficiency is in 91.2% ~ 96.7% scope.
The extraction hydrogen sulfide content is 100mg/m
3Doctor solution rich solution 1L, utilize the vacuum membrane distillation method under 55 ℃ and 65 ℃, to carry out respectively desorption and regeneration, the rich solution flow is controlled at 50L/h, shows that through 30 minutes regeneration tests regeneration rate can reach more than 95%, the results are shown in Table 2.
Table 1 desulfurization
Prescription |
Temperature/℃ |
Soak time/min |
Desulfuration efficiency/% |
Embodiment 1 |
23 |
30 |
93.6 |
Embodiment 2 |
23 |
30 |
91.2 |
Embodiment 3 |
23 |
30 |
96.7 |
Embodiment 4 |
23 |
30 |
96.3 |
Table 2 rich solution regeneration tests
Prescription |
Temperature/℃ |
Recovery time/min |
Regeneration efficiency % |
Embodiment 1 |
55 |
30 |
95.1 |
Embodiment 2 |
55 |
30 |
95.7 |
Embodiment 3 |
65 |
30 |
96.8 |
Embodiment 4 |
65 |
30 |
97.2 |