The Realization of Coal Liquefaction in the Continum Model System and the Experimental Research of Coal Liquefaction
|School||Harbin Institute of Technology|
|Keywords||Direct coal liquefaction Continum plant Experimental research Modeling|
The small oil-rich coal resources of China decides that we have to give priority to coal in energy consumption structure, but now there are some problems like low utilization and serious pollution to the environment in using coal. As an important cleaning coal technology, coal liquefaction becomes an important way that can use coal resources effectly and solve the lack of oil.This paper is mainly about: the analysis and summary of liquefaction process at home and abroad; the design of liquefaction experiment with continuum plant; study the effect of alkaline pretreatment, the proportion of the heavier residue in coal slurry and the velocity of adding raw materials on the oil yield. Apply the similar theory in the design of coal liquefaction experiment with continue system.Determine the main parameters of reaction vessel and the process of coal liquefaction experiment with continue system by design and calculation. The system is mainly made of heater, mixer, emulsifying machine, meter pump, reaction vessel, separator, compressor and separator, compressor and rectifying column. Determine mm（ is the equivalent diameter of reaction vessel）, =1.3m（ is the length of reaction vessel）. Divide the reaction vessel with bubble column into two, each height is 0.65m. d dl= 40d dll lStudy the liquefaction properties of Yilan coal with the continuous experimental system（natural bauxite No.1 is the catalyst; heavy oil fractions is the hydrogenation solvent）. The results showed that: when the concentration of NaOH is 1% in the experiment of pretreating the coal with alkali, the light fraction within 453 K is 1.8 times of the not pretreat yield; at the same time the total oil yield is 1.08 times of the not pretreat yield. In the experiment of using a mixture of the heavier coal liquefaction production whose boiling point is higher than 623K and the heavy residue of coal liquefaction as solvent on the pressure of 0.40.5MPa, it shows a good oil yield; when the proportion of heavy residue in the mixture reached 25 percent, the third distillate apparent peak, and at the same time of the totle oil yield isn’t decrease a lot, so the liquefaction effect is good. The increase of the raw material supply rate have great role in preventing the particle settling and stratification of the flow, in the experimental the oil yield is increase with the supply rate increase, the best raw material supply rate is 2.0kg/h.According to the feature of coal liquefaction experiment with continue system, deduce the similarity criterion of experimental system and the condition of amplifying the model, particle flow around Reynold number accord with Stokes law, Fr and Stk are the approximately qualitative model criterions. Calculation to obtain the velocity of mixture is 3.70×10-3m/s and the particles size is smaller than 0.126mm by geometrically magnifying 100 times.