Tutor : Fenrong Liu. College of chemistry and chemical engineering Inner Mongolia University China

Transcription

1 Sulfur removal and release behaviors of sulfur-containing compounds during pyrolysis under CO 2 atmosphere Xinlong Wang Tutor : Fenrong Liu College of chemistry and chemical engineering Inner Mongolia University China

2 Contents 1 Background 2 Experimental 3 Results and ddiscuissioni i 4 Conclusions

3 1. Background Coal, main energy and chemical raw materials, plays an important role in the energy structure of China.But large-scale use of coal in China has caused great damage to the environment.

4 1.1 The dangers of sulfur in coal Acid rain can cause soil acidification. Acid rain also accelerates the loss of soil mineral nutrients, changing the soil structure, resulting in poor soils, thereby affecting the normal development of plants; Too much CO 2 emissions caused global warming and glaciers melting in Antarctica

5 1.2 The presence of sulfur form Organic sulfur Thiophene Sulfoxide Sulfide Disulfide sulfone mercaptans sulfur in coal inorganic sulfur Pyrite Free sulfur Sulphate sulfur Sulfur in coal occurs in both inorganic and organic forms. The inorganici sulfur is mostly pyrite and small amounts of sulfates. The organic sulfur is usually categorized as mercaptans, sulfones, sulfides, sulfoxides, disulfides and thiophenes.

6 experimental 2.1 Samples samples 2 Experimental tetradecyl mercaptan 2-memethyl thiophene benzothiophene Active carbon dibenzothiophene dibutyl sulfide phenylsulfide 6

7 2.1 Experimental Py-MS equipment( mass spectrometer with pyrolysis) Model compound samples about 1.5 g were placed into a quartz reactor and heated from room temperature to 1000 at a heating rate of 10 /min in a continuous flow of pure Ar or pure CO 2 atmosphere at a flow rate of 200 ml/min. A mass spectrometer was used to measure H 2 S,COS, SO 2, CO, etc. online. 7

8 Py-GC equipment (gas chromatography) Pyrolysis experiments were carried out in a quartz tube fixed bed reactor (i. d. 35 mm, length 60 cm). About 1.0 g coal was pyrolyzed under pure Ar or pure CO 2 atmosphere at the temperature range from 2 room temperature to 1000 with gas flow rate of 200 ml/ min at heating rate of 10 /min. H 2 S, COS 2 and SO 2 were analyzed by gas chromatography (GC) with FPD.

9 3. Results and discuission Table 1 Char yields and sulfur removal ratios of samples during pyrolysis under different atmospheres Ar CO 2 Samples Char yield/% sulfur removal ratio/% Char yield/% sulfur removal ratio/% active carbon dibutysulfide dibenzothiophone methyltipophene tetradencylmarcaptan phenyl sulfide benzothiophene h

10 3.1 The COS evolution lines under CO 2 atmosphere 2.00E E E E E E-011 benzothieophen p h enylsulfide lfid tetradecylmarcptain 422 o C 2-methyl thiophene 515 o C 537 o C 0.00E E E-011 didenzothiphene 493 o C 744 o C 1.00E-010 dibutysulfide 367 o C 1.00E-012 acyive caybon T e m perature / C Fig 1 The COS evolution lines of samples during pyrolysis under CO 2 atmosphere

11 3.2 The H 2 S evolution lines under CO 2 atmosphere 2.00E E E E E E E-010 benzothieophen phenylsulfide tetradecylmarcptain 1.40E methlyhiophene 1.20E E-011 didenzothiphene 1.20E E E E-011 dibuty sulfide acyive caybon 1.00E Fig 2 The H 2 S evolution lines of samples during pyrolysis under CO 2 atmospheres

12 3.3 The SO 2 evolution lines under CO 2 atmosphere 3.00E-011 benzothieophen 2.00E E E-011 phenylsulfide 8.00E E E E E E E E E E tetradecylmarcptain 2-methlyhiophene didenzothiphene dibutysulfide acyive cayb on 1.00E Temperature / C Fig 3 The SO 2 evolution lines of samples during pyrolysis under CO 2 atmosphere

13 3.4 The sulfur content gases evolution of dibutysulfide 7.00E E-010 SO 2 -CO E E-010 intens sity 3.00E E E-010 H S-CO 2 2 COS-CO 2 SO 2 -Ar H 2 S-Ar COS-Ar Temperature / C Fig 3 The sulfur content gases evolution lines of dibuty sulfide during pyrolysis under different atmosphere

14 35sulfurcontaining 3.5 sulfur-containing gases evolution Table 2 sulfur-containing gases evolution amount under different conditions (g/g coal) Samples Ar CO 2 H 2 S COS SO 2 total H 2 S COS SO 2 total dibutysulfide 1.05E E E E E E E E-03 dibenzothiophene 7.45E E E E E E E E-03 2-methyltipophene p 4.31E E E E E E E E-03 tetradencyl marcaptan 1.08E E E E E E E E-02 phenyl sulfide 1.47E E E E E E E E-03 benzothiophene 1.52E E-0587E 4.14E E E E E E-03

15 4 conclusions (1) Sulfur was released in the order of dibutyl sulfide> tetradecyl mercaptan > 2-methylthiophene > benzothiophene> phenylsulfide > dibenzothiophene during pyrolysis under CO 2 atmosphere. While the sulfue-contenting gas evolution amount order tetradecyl mercaptan>dibuty sulfide>> phenylsulfide 2-methylthiophene > benzothiophene> >dibenzothiophene during pyrolysis under CO 2 atmosphere. (2) The decomposition temperatures of all of the sulfur compounds were lower during pyrolysis under an CO 2 atmosphere than it under inert atmosphere, which indicates that CO 2 can break C S bonds easily.

16 (3) Most sulfur compounds can transfer to gas phaseunder an CO 2 atmosphere with little loss of carbon. (4)Under CO 2 atmosphere, some sulfur radicals can react with CO 2 and release in the form of COS.

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