The Process Research And Design For Coal And Biomass Gasification Synthesis Gas To Fischer-Tropsch Oil Fuel

As the price of international crude oil continues to rise but the storage of oil continues to fall, the energy structure of our country should be adjusted as soon as possible. Based on the unique character of "rich coal, less oil and short gas", CTL becomes a quick way to solve problems. However, using too much coal will cause severe pollution to environment. Another way of producing oil by biomass is an environmentally friendly industry, characterized by reproducibility, but the technology of producing oil only by biomass is not mature and the comprehensive cost is very high. Therefore, if combining coal and biomass, not only the amount of coal used will be less, which is very good to environment, but also the present mature technology could be used and economic value will be added.At present, many large-scale enterprises are choosing coal to produce oil, and the technology has become mature. While, producing oil by biomass is only conducted in laboratory and small size gasification furnace. Thinking of the advantage of biomass energy, many scholars at home and abroad is doing deep research on its using ways. Fermented ethanol is more mature, but its cost is high. On the research of replacing fuel of petroleum-based, combining with coal is used more often. Some studies show that due to different structural characteristics of biomass and coal, co-gasification could affect synergistically, which could increase coal gasification ratio and reduce tar produced by biomass.This thesis takes literatures as reference and use Aspen Plus software to complete design and development of coal and biomass gasification producing Fischer-Tropsch oil, paying much care to study the effect of different biomass content and design procedures on product and energy distribution.In the process of producing oil by using coal, lots of CO2will be produced. The quality of C takes up about60%of the total carbon number, which makes much energy run off. The main reason is that the H2/CO of synthesis gas is too low, so much amount of CO is needed to transfer with water gas. Biomass is rich of hydrogen, and could increase H2/CO initial ratio of synthesis gas by gasifying with coal and decrease the producing of CO2, and energy consumption. The model in this thesis checks the influence of different ratio biomass content in raw material on synthesis gas and discharge of CO2.The key of high-efficient synthesis gas to FTL is its catalyst choice. Distribution of Fischer-Tropsch reaction products has its regularity, which is called ASF distribution coefficient. This thesis imitates influence relation of this coefficient to different components, and calculated the number of C distribution of different hydrocarbon products.As catalyst could not make all synthesis gas into oil products, part energy of synthesis gas probably will be lost. In this simulation, cogeneration unit is added. Simulate design principal of IGCC in literature, and output the redundant synthesis gas in form of electricity products, which could maximum usage of energy. The energy distribution of different proportional oil-electricity is calculated with ASF distribution.CO conversion ratio of synthesis gas by Fischer-Tropsch reaction is60%-80%, while after adding synthesis gas self thermal cycle, the ratio will increase to above90%, the amount of oil products will be increased effectively, and utilization ratio of energy will be increased. But amount of electricity products will decrease a lot. The key to choose the above two technological processes is the choice of target products.The direct reason of global warming is the discharge of greenhouse gas. Collection and storage of the produced CO2directly could decrease its discharged amount, but energy consumption in the whole technology process will be increase by30%-40%. C in biomass comes from CO2in air. Collection and storage device added with CO2could decrease90%discharge. It is found in the simulation that if adding39%biomass in the raw material,"zero release" of CO2could be achieved, which is good to improve environment.After the complete calculation to the built model, it is found that in the technological processes of coal and biomass synthesis gas going through Fischer-Tropsch reactor one time, more than50%energy could be used.