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 Oilfield Gas |
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| The desulfurization system for refining tail gas of oil shale in Yaojie Coal and Power Group with DDS Biological Desulfurization Technology runs normally |
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| Oil shale is used for oil refining by dry distillation in Yaojie Coal and Electricity Group Co. , Ltd. The tail gas of refining can be used as fuel for power generation. However, there is H₂S with the concentration of 700 ~ 2900mg/Nm³ in the tail gas resulting in high failure rate of gas generator set, affecting equipment life and reducing power generation capacity. At the same time, it will also cause a large amount of SO₂ in the flue gas after combustion of tail gas to be discharged into the atmosphere and pollute the atmospheric environment. The original supporting 24000Nm³/h tail gas desulfurization system uses PDS desulfurization method to remove hydrogen sulfide, and then sends the tail gas to internal combustion engine for power generation. The desulfurization efficiency is not high, it can reach about 80% at first, and then gradually reduce to 20%, which does not play a role in protecting power generation equipment and reducing flue gas pollutant emission. Since November 2020, DDS biological desulfurization technology has been used to remove hydrogen sulfide from refining tail gas. At present, the ststem operation is stable, and the export hydrogen sulfide content reaches less than 20mg/Nm³. |
| Oil Shale is a kind of sedimentary rock with high ash content and combustible organic matter. The main difference between it and coal is ash content of more than 40% , and between it and carbonaceous shale is oil content of more than 3.5% . After oil shale retorting, the content of tar and dust in the tail gas is higher, which is more important to the desulfurization catalyst. Through the analysis of the sulfur discharged from the sulfur-melting kettle, the part of which is blackened in color and contains a lot of dust and oily substances, it shows that the dust and oily pollutions in the gas have been washed and absorbed in the desulfurization tower, and then discharged from the system together with the sulfur foam through the action of DDS catalyst and bacteria. The influence of dust and other impurities on the generator equipment is reduced.
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| In the process of the system running, it has also undergone many parameter debugging and operation running-in improvement, and gained some experience and results. |
- DDS biological desulfurization technology is essentially different from the traditional wet desulfurization technology. The concentration of catalyst and bacteria in the desulfurization solution should be kept within the design standard range. The higher fluctuation of which may reduce the desulfurization efficiency.
- The sulfur particles produced by DDS biological desulfurization technology do not block up in the tower. The desulfurization system do not need to drain off solution, and do not need to deal with by-produced salt specially. Therefore, the problems causing loss of desulfurization solution such as leaking of equipment, so should be avoided.
- The correct treatment of sulfur foam is an important factor affecting the operation of the desulfurization system. The sulfur foam particles produced by DDS biological desulfurization technology are smooth and fine, and the quantity of the foam is large. It is suitable to be treated by filter such as plate-frame filter press. The clean filtrate returns to desulfurization systen to be recycled. Sulfur paste can be melted with intermittent sulfur melting autoclave to produce high purity sulfur product. untreated sulfur foam should not be returned to the desulfurization solution system.
- The higher content of dust and tar in the tail gas of oil shale refining has a great influence on the desulfurization catalyst. DDS catalyst and bacteria can absorb these impurities and discharge them through the sulfur foam system, which can purify the tail gas of oil refining more thoroughly, and is favorable for the stable operation of the power generating device.
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