Effect Of Pyrite For Longkou Oil Shale Organic Matter And Char Functional Groups During Pyrolysis

China’s energy resources have such characteristics of “rich in coal, oil-poor, less gas”, and the reserve and production ratio for oil is 11.4 years, while imported oil accounts for 60%. China has enormous oil shale resources which can be converted into shale oil as an alternate to conventional oil by retorting. During pyrolysis, sulfur in pyrite will be transferred into the product which can pollute environment and corrode equipment. On the other hand, pyrite has effect on pyrolysis. Therefore, Studying the effect of pyrite in the process of oil shale pyrolysis has great significance.In order to exclude the impact of other mineral matter for oil shale retorting process, this research adopts washing oil shale with HCl-HF-HNO3 to obtain Longkou oil shale organic matter, analyze the effect of mineral matter and various functional groups during acid pickling. Study the impact of iron oxide, elemental sulfur and pyrite for product yield、Non-condensable gas release and char oxygen functional groups in horizontal furnace carbonization test rig.Analysis the effect of acid pickling for oil shale by XRD and FTIR, the results indicate that HCl-HF-HNO3 could remove 98.5% ash and obtain relatively pure organic matter. But acid pickling could make difference on the structure of organic matter. Acid pickling cause aromatic structure transport into two hydrogens per ring, organic salts convert to organic acids, increase carboxylic acids and phenolic hydroxyl at the same time. With regard to aliphatic structure,acid pickling will increase the proportion of asymmetric CH2 and length of aliphatic chain. For the perspective of hydroxyl, acid pickling could destroy OH-O.The effect of acid pickling for oil shale by TG/DTG, the results indicate that acid pickling reduce the pyrolysis temperature at the beginning and the end, increase pryolysis rate. However acid pickling have little effect on maximum weight loss which means acid pickling will not evidently change the main structure of organic matter. By acid pickling, mineral matter in Longkou oil shale could restrain pyrolysis.Analysis of char functional groups FTIR spectra shows that organic matter has been completely decomposed under the condition with 500℃ ultimate temperature, 40 min residence time. Pyrolysis can cause aliphatic chain rupture, decreased oxygen functional groups where carboxylic acids has been completely decomposed.For aromatic hydrocarbon, pyrolysis can make aromatic hydrogen replace degree rise, the way of replace is toward hydrogen content reducing. Iron oxide, sulfur and pyrite will promote the aromatic hydrocarbon replacing, excessive iron oxide and pyrite could increase the content of three hydrogens per ring, sulfur could increase the content of four hydrogens per ring. Three kinds of additives restrain macromolecule condensation and increase ratio of CH2/CH3 in char. When add 40% sulfur, CH3 symmetric stretching vibration intensely increases in FTIR spectra 2870cm-1. The results show that excess sulfur promotes aromatic circle fractured and increases the degree of branched chain.In the process of pyrolysis, iron oxide, sulfur, pyrite all promote effect on organic macromolecular fracture. Iron oxide and sulfur are reducing the tar production rate, promote the formation of the non-condensable gas. With the increase of mixing pyrite, tar production decreases and then increases, gas production appears a trend of rise first and then decrease. CO and CO₂ generate prior to CH₄ and C₂H₆. Iron oxide can raise the yield of CO₂, reduce the yield of CO, CH₄ and C₂H₆. Sulfur can raise the yield of CO, reduce the production rate of CO 2, CH₄ and C₂H₆, while addition of sulfur will make the four gases start generating latterly. Pyrite can raise the yield of CO₂, and the yield of CO, CH₄ and C₂H₆ firstly rise and then decrease, it reaches maximum when pyrite mixing counts 2%.