A Study On The University Research Institutes During The Republic Of China

In order to achieve the "dual carbon" strategic goal and accelerate the pace of reducing carbon emissions,it is necessary to reduce dependence on traditional fossil energy and vigorously develop renewable resources.Some solid wastes containing carbon(such as biomass,plastics,etc.)can be converted into high-quality syngas through pyrolysis,and further synthesized into liquid fuel or chemical products,which is a kind of renewable resources with development prospects.Preparation of syngas is solid waste pyrolysis related study,main problems focus on how to effectively improve the quality of syngas and yield,and reducing the tar production,based on the above issues,conducted in solid wastes(biomass,PVC)as the raw material of preparation of syngas by catalytic pyrolysis,examined the influence of different reaction conditions of solid waste pyrolysis process,The reaction mechanism during pyrolysis was discussed.At the same time,aiming at the problem that the content of carbon dioxide in the pyrolysis gas is too high,perovskite oxide is used as the carrier to support the ferric oxide as the catalyst for reverse water gas reaction,and the carbon dioxide in the pyrolysis syngas is hydrogenated to carbon monoxide.Finally,the synthesis of low carbon alcohol was studied using Cu/Zn-Al catalyst with hydrogen and carbon monoxide mixture as raw material,which provides a theoretical basis for the rapid and harmless treatment and resource utilization of solid waste.The main research work is as follows:(1)The pyrolysis characteristics of wood powder loaded with potassium carbonate and potassium chloride and the formation mechanism of its products were studied in a fixed-bed reactor.The results show that potassium carbonate can increase the yield of gas and carbon residue after wood powder pyrolysis,but decrease the yield of tar.The yield of gas increased by 5%,residual carbon increased by 8%and tar decreased by 12%.At the potassium carbonate concentration of 7.5 wt%,the production of hydrogen and carbon dioxide reached 2.5 and 3.5 mmol/g,respectively.Different from potassium carbonate,the total gas yield decreased slightly with the increase of potassium chloride concentration,in which the yield of hydrogen decreased by 0.8 mmol/g.At the same time,the effect of potassium chloride on the residual carbon of wood powder pyrolysis is not obvious,and the yield of residual carbon only increases by less than 2%.The yield of tar increased by 4%with the increase of potassium chloride concentration.Potassium carbonate can promote further dehydration and isomerization of ketones and alcohols,and form a large number of ketones and esters with small molecular weight.At the same time,it can also promote the branch chain fracture of wood powder structure and further decarbonylation and dehydrogenation reaction,and generate more gas products.Potassium chloride increased the contents of furans and aldehydes in the pyrolysis tar products mainly by promoting the ring-opening of pyran in the intermediate products.The change of potassium chloride content had little effect on tar composition.On the basis of the study,in order to further increase the production of hydrogen,reduce the production of carbon deposition,in the process of catalytic pyrolysis wood powder into water vapor in the atmosphere,the experimental results show that:at 750℃,with the increase of water/carbon ratio,hydrogen content in gas after the first increase trend,when water/carbon ratio of 0.3,the hydrogen content in the syngas as high as 58%.Under the pyrolysis temperature of 750℃ and water/carbon ratio of 0.3,the effect of potassium carbonate concentration on the pyrolysis process of wood powder was studied.The results show that the hydrogen content in syngas is 64%when the potassium carbonate concentration is 7.5 wt%.Under the synergistic action of potassium carbonate and water vapor,the formation path of tar changes during the pyrolysis process,resulting in a decrease in the content of reconstituted components and an increase in the content of light components.(2)The effect of in-situ catalysis of potassium carbonate on polyvinyl chloride pyrolysis was studied in a fixed-bed reactor in nitrogen and carbon dioxide atmosphere respectively.The results show that the pyrolysis process of PVC can be divided into two stages:the first stage is the removal of hydrogen chloride from PVC,and the macromolecules break into free radicals with shorter carbon chains;In the second stage,various free radicals recombine and transform to form tar components,mainly benzene series and polycyclic aromatic hydrocarbons.Potassium carbonate traps hydrogen chloride in the first stage of polyvinyl chloride pyrolysis and promotes the rupture of long carbon chains.In the second stage,the ring-opening reaction between benzene series and polycyclic aromatic hydrocarbons was promoted to reduce the production of heavy components in tar.On the basis of the above research,the effects of two transition metal oxides on the pyrolysis process of PVC were further studied.The experimental results show that the first type of transition metal oxides(V2O5,MoO3,TiO2)formed stable physical bond bridge structure through reduction coupling mechanism to promote the cross-linking reaction between molecules,thus reducing the content of aromatic hydrocarbons in tar components.The second kind of transition metal oxides(CuO,Fe2O3,ZnO,MnO2)form Lewis acid by complexing hydrogen chloride,which promotes the removal of hydrogen chloride from polyvinyl chloride and the formation of trans-polyolefin structure,thus reducing the formation of benzene ring structure,resulting in the reduction of benzene compounds in tar components.(3)In order to solve the problem of high carbon dioxide content in pyrolytic syngas,the excess carbon dioxide is hydrogenated to carbon monoxide by reverse water gas reaction.BaZr0.9Y0.1O3 with perovskite structure was prepared by solid state reaction method,and BaZr0.9Y0.1O3 was supported by ferric oxide as catalyst for the hydroreforming of carbon dioxide.The calcination time of BaZr0.9Y0.1O3 carrier and the effect of ferric oxide loading on the catalytic activity were investigated.The catalysts were characterized by X-ray diffractometer(XRD),scanning electron microscope(SEM)and temperatures-programmed adsorption and desorption device.The experimental results show that BaZr0.9Y0.1O3 carrier calcined for 5 hours has good crystallinity and abundance.The particle size is uniform and the surface is smooth.The specific surface of BaZr0.9Y0.1O3 is 4.387 m2/g,and can be uniformly dispersed on the BaZr0.9Y0.1O3 carrier after ferric oxide loading.The catalyst prepared by this method has the best reaction activity.Under the conditions of 650℃ reaction temperature,2400 mL/(g*h)reaction space velocity,hydrogen and carbon dioxide feed ratio of 1,the catalyst supported with 5 wt%ferric oxide has the best reaction activity,and the carbon monoxide conversion rate is 31%.A small amount of methane is produced as a byproduct during the reaction,but the selectivity of carbon monoxide is high,reaching 96%.The carbon monoxide conversion remained stable over a catalyst loaded with 5 wt%ferro oxide for 27 h at 650℃.(4)Use Cu/Zn-Al catalyst to synthesize methanol from a mixture of hydrogen and carbon monoxide under low pressure.The methanol conversion under different reaction conditions(reaction pressure,reaction temperature,reaction space velocity)was studied.The catalytic stability of Cu/ZnA1 catalyst was investigated in a long-time continuous reaction process,and the changes of catalyst before and after the reaction were studied by X-ray diffraction(XRD).The experimental results show that methanol conversion increases with the increase of reaction pressure in the range of 0.6～1.2 MPa,reaction temperature in the range of 200～260℃ and reaction space velocity in the range of 300～750 h1,and reaches the maximum at 1 MPa.Then,as the reaction pressure continued to increase,methanol conversion slightly decreased,accompanied by an increase in by-products.For the reaction temperature,methanol conversion increases with the increase of the reaction temperature,and reaches the maximum at 240℃.Then,as the temperature continued to increase,the methanol conversion rate decreased slightly,while the by-products increased significantly.In the range of 300～750 h-1,methanol conversion has no obvious change.The optimum reaction conditions within the range of study are reaction pressure 1 MPa,reaction temperature 240℃ and reaction space time 450 h-1,under which methanol conversion is 21.33%.X-ray diffractometry(XRD)showed that the catalyst was reduced and Cu0 and Cu1 coexisted during the reaction.The methanol conversion rate remained stable after 30 hours of reaction on the catalyst.