Study Of The Effect Regularity Of Alkali Matters On The Combustion And Pollutant Emission Characterictics Of Coal Blending With Biomass

Nowadays, the world faces more and more serious energy and environment problems. The conventional fossil energy gradually dries up, and it puts enormous pressure on the entironment in its utilizing process. So the clean and reproducible energy is paid more and more attention. Biomass energy, a kind of clean and reproducible energy, is laid store by the world countries for its abundant resources and environment protect. Combusting biomass with coal is one of the economical and effective methods utilizing biomass. There are many metal compounds in biomass, and most of them are alkali, alkali-earth and transitional metal compounds, which can play an important role in the thermochemistry transformating process of biomass. So it is practically significant to study how these compounds act in the thermochemistry transformating process of biomass and its blending with coal.Biomass has particular fuel properties, and the content of alkaline compounds is quite high. So, it can bring questions such as deposit, slag and corrosion. Blending with coal can reduce the possibility of the occurrence of these questions. At the same time, the existence of these alkaline compounds can play an important role on the combustion and pollutant emission characteristics of biomass blending with coal. Understanding these influences has great significance for instructing boiler operation and controlling pollutant emission. In this text, one coal and five kinds of biomass were used to research the rules how the alkaline compounds affected the combustion and pollutant emission characteristics of biomass blending with coal.First of all, the thermal gravimetric analysis method was applied to research the combustion charecterastics of the biomass and its blending with coal. The alkali matters were removed from biomass by HCl washing method in order to research its effection on the combustion charecterastics of the biomass and its blending with coal. The results show that, removing alkali matters makes the combustion curve of biomass and its blending with coal moves toward the high temperature. Accordingly, the ignition and burnout temperature, the corresponding temperatures of the maximum combustion rate of volatile and coke all increase notably. The maximum combustion rate of volatile increases, and that of coke decreases. Three kinds of alkali matters were added to biomass in order to research its effection on the combustion charecterastics of the biomass and its blending with coal. The results show that, adding K₂CO₃ makes the ignition and burnout temperature of biomass and its blending with coal show a decreasing trend, the maximum combustion rate of volatile and coke all decrease, and the corresponding temperature of the maximum combustion rate of volatile and coke all increase. Adding CaO and MgO, makes the burnout temperature of biomass and its blending with coal show an increasing trend, the maximum combustion rate of volatile and coke all decrease, and the corresponding temperature of the maximum combustion rate of volatile and coke show an increasing trend. The ignition temperature of biomass shows an increasing trend, and that of its blending with coal shows a decreasing trend.Next, the tube-type furnace combustion system was used to research the SO₂ release characteristics of biomass and its blending with coal. The alkali matters were removed from biomass by HCl washing method in order to research its effection on the SO₂ emission charecterastics of the biomass and its blending with coal. The results show that, removing alkaline compounds from biomass makes SO₂ release beginning and the corresponding time of its peak value of the biomass and its blending with coal all move backward, and its peak value increase. The SO₂ release total value of biomass increases, but that of its blending with coal shows a decreasing trend. Three kinds of alkali matters were added to biomass in order to research its effection on the SO₂ release charecterastics of the biomass and its blending with coal. The results show that, adding alkali matters makes SO₂ total release time of biomass and its blending with coal move forward, and SO₂ peak value and total release value decrease greatly.In the end, the tube-type furnace combustion system was used to research the NO release characteristics of biomass and its blending with coal. The alkali matters were removed from biomass by HCl washing method in order to research its effection on the NO emission charecterastics of the biomass and its blending with coal. The results show that removing alkaline compounds makes NO release beginning time of the biomass and its blending with coal move backward, and release peak and total value all show a decreasing trend. Three kinds of alkali matters were added to biomass in order to research its effection on the NO release charecterastics of the biomass and its blending with coal. The results show that, adding alkali matters makes NO total release time move forward. NO total release value of biomass decrease. Adding K₂CO₃ makes the NO total release value of the blending of biomass with coal decrease. Adding CaO to the blending of biomass with coal makes NO total release value show different characteristics according to biomass species. Adding MgO makes the NO total release value increase.In this text, experiments were done to research the combustion and pollutant emission characterastics of the biomass blending with coal, and the main research was the effection discipline of alkali matters on the pollutant emission characteristics in order to provide valuable referenced laws for co-combustion technology of biomass blending with coal.