Effect Of Conditions And Additives On The Removal Of Solid Phase Nitrogen During Pyrolysis Of Lyuliang High-sulfur Fat Coal

In recent years,smog continues to grow during the winter in Northern China.The reason is that coal burning is one of the important factors leading to smog weather.Because some rural areas in Northern China and suburban areas cannot popularize “coal to electricity”,“coal to gas” and "centralized heating",so it causing irregular burning can be seen everywhere in remote areas.Disperse coal is mainly used for kitchen cooking,and industrial production.The coal quality is poor.Raw coal burns widely and the government is difficult to supervise,meanwhile the stove lacks to desulfurization,denitrification and dust removal device.Therefore,raw coal is a kind of pollution source that cannot be ignored.Now the search for a clean coke instead of civil burning coal is one of the most effective measures to solve atmospheric pollution,especially in controlling the emission of sulfur oxides,nitrogen oxides and dust particles.On the other hand,clean coke has a significant effect in the past time.The idea achieve clean and green fuel in advance,and to implement emission reduction effects at the source of combustion.At present,clean coke has high-temperaturefixing sulfur,low ignition point and excellent combustion performance are more suitable for use in civil stoves.However,due to insufficient consideration of denitration performance of clean coke during research and preparation,the nitrogen content in fuel remains high.The nitrogen content in clean coke is an urgent problem to be solved.In this paper,the effects of pyrolysis atmosphere,pyrolysis temperature,heating rate and coal particle size on coke nitrogen content in the product were investigated,and the experimental conditions for the pyrolysis of Lyvliang fat coal were determined.Secondly,a single iron auxiliary agent and an iron-nickel composite auxiliary agent are separately introduced into the preparation process of clean coke,wherein the loading of the composite auxiliary agent is studied by means of swelling and impregnation treatment,and the iron-nickel composite auxiliary agent is studied at different pyrolysis temperatures.The influence of coke nitrogen determined the optimal loading ratio of iron-nickel composite additive.Finally,the pyrolysis behavior,elemental composition,phase and surface physical structure of the experimental samples were determined by modern characterization instruments TG-MS,XPS,XRD and BET.Tests were carried out to determine and infer the main influencing factors and mechanisms for the removal of nitrogen from coal in the pyrolysis process of Lyvliang.The main results include the following:(1)There are four kinds of nitrogen elements in Lyvliang's fat coal,which are five-membered cyclopyrrole nitrogen(N-5),six-membered cyclopyridylnitrogen(N-6),and internal nitrogen structure quaternary nitrogen(N-Q).Nitrogen oxide nitrogen form(N-X),in which the sum of pyrrole type nitrogen,pyridine type nitrogen and nitrogen oxide nitrogen accounts for about 85%,and the nitrogen content at the edge of coal molecules in Luliang fat coal is large.The minerals in Luliang's fat coal are mainly kaolin,quartz,calcium aluminosilicate,calcium carbonate and pyrite.After treatment with hydrochloric acid and hydrofluoric acid eluting ash,only pyrite remains in the coal;(2)The optimum process conditions for the pyrolysis process of Lvliang fat coal is beneficial to the removal of solid phase nitrogen.The pyrolysis carrier gas is 50ml/min argon gas,the particle size is larger than 80 mesh,and the heating rate is 5 °C/min;(3)The form of nitrogen in the solid product coke at the pyrolysis temperature of 700-1000°C,compared with the form of nitrogen in the raw coal,the proportion of pyrrole nitrogen in the coke decreased with the increase of temperature,while the content of pyridinium nitrogen Raise.The pyrrole nitrogen changes to a more stable pyridinium nitrogen with increasing temperature,but at 1000?,the proportion of pyridinium nitrogen also decreases.At the pyrolysis temperature of 800?,nitrogen oxide nitrogen basically disappears.(4)The supported single-agent iron has a significant effect on the removal of nitrogen from the pyrolysis process of the raw coal.When the pyrolysis temperature is 800??900??1000?,the load mass fraction is 0.8%,and thebest is removed.The rate is that the composite additive iron-nickel treated by the swelling impregnation method greatly improves the pore structure parameters of the coal particles,is beneficial to the high-efficiency loading of the additives,and further improves the solid phase nitrogen removal.(5)Nitrogen oxide concentration released from combustion of four kinds of solid fuels of raw coal,900? pyrolysis coke,900? pyrolysis coke,and iron-nickel composite additive 900°C pyrolysis coke on fixed bed evaluation equipment Gradually reduce,the specific order is: raw coal > 900? pyrolysis coke > load a single additive iron 900? pyrolysis coke > load iron nickel composite additive 900? pyrolysis coke.Treatments such as heat treatment and load aids are effective for preparing clean coal-based fuels.