摘要:
In a process of simultaneously producing fuel gas and process heat from carbonaceous materials wherein the carbonaceous materials are gasified in a first fluidized bed stage and the combustible constituents left after the gasification are subsequently burnt in a second fluidized bed stage the throughput rate and the flexibility are increased in that the gasification is carried out at a pressure of up to 5 bars and a temperature of 800.degree. to 1100.degree. C. by a treatment with oxygen-containing gases in the presence of steam in a circulating fluidized bed and 40 to 80% of the carbon contained in the starting material are thus reacted. Sulfur compounds are removed from the resulting gas in a fluidized state at a temperature in the range from 800.degree. to 1000.degree. C. and the gas is then cooled and subjected to dust collection. The gasification residue together with the by-products which have become available in the purification of the gas, such as laden desulfurizing agent, dust and aqueous condensate, are fed to another circulating fluidized bed and the remaining combustible constituents are burnt there with an oxygen excess of 5 to 40%.
摘要:
A process for producing cement, including preheating a mixture of ground raw materials (raw meal) in a preheating cyclone to form a preheated raw meal, calcining the preheated raw meal in a calciner to form a calcined raw meal, burning the calcined raw meal in a rotary kiln with the aid of a high-grade fuel to form a cement clinker, cooling the cement clinker in a rotary kiln and grinding the cooled cement clinker. The process is characterized by replacing 50 to 70% of the high-grade fuel with a low-grade fuel, gasifying the low-grade fuel in a fluidized bed to form a resulting fuel gas, supplying a first portion of the resulting fuel gas to a main burner of the rotary kiln, a second portion of the resulting fuel gas to the exhaust gas stream from the rotary kiln and a third portion of the resulting fuel gas to the calciner.
摘要:
A reactor for combusting fine-grained solid fuels in a circulating fluidized bed contains a combustion chamber, which is provided with lines which open in the lower portion of that chamber and serve to feed primary air, secondary air and solid fuel. The fluidized bed combustion chamber is divided into compartments by at least one partition provided in the upper portion of the fluidized bed combustion chamber. Each compartment communicates through a passage with at least one solids separator, which is connected to means for recycling solids and communicates with the compartment through a passage.
摘要:
Granular coal is combusted in a circulating fluidized bed system comprising a combustion chamber, a separator and a recycle line for recycling solids from the separator to the combustion chamber. Gas from carbonization is added to the oxygen-containing combustion gas withdrawn from the combustion chamber and is at least partly combusted in said combustion gas to increase the temperature of the combustion gas to about 850.degree. to 1200.degree. C. The gas from carbonization is produced by the heating of granular coal.
摘要:
Disclosed is a process for improving the solids distribution in a circulating fluidized bed system. In the invention, hot ash from the system and fresh carbonaceous fuel are mixed in a chamber which is fluidized so as to form a fluidization zone wherein the heavier material is concentrated and a second fluidization zone which consists predominantly of fines at least a portion of which is separated from the heavier material. This zone separation is facilitated in part by maintaining different gas-mass flow rates so as to form a plug of heavier material. At least a portion of the fine material is then transferred into the reactor while the coarse material is further processed.
摘要:
A method for regulating or controlling the content of NOx in the exhaust gases of a glass-melting furnace having several burners operated in alternation, wherein both the beginning and the end of a combustion break (FP+, FP−) are supplied to a binary signal generator (8) which passes a signal to a regulator (4) with a time delay and upon receipt of the time-regulator (4), and the amount of NH3 supplied to the denitrating plant is adjusted to a lower constant fixed value F1 via a control, and by means of a memory element (7) a higher constant fixed value F2 is calculated as amount of NH3 and supplied to the regulator (4), whereupon as soon as the regulator (4) has received the signal of the time-delayed end of a combustion break, the fixed value F1 is adjusted to the fixed value F2 via a control, and subsequently the regulation is directly continued.
摘要:
The process for dry desulfuration of a combustion gas includes providing an electrostatic precipitator (12) or an inertia force separator for dedusting; dedusting the combustion gas at temperatures of 100.degree. C. to 180.degree. C. in the electrostatic precipitator or at temperatures of 100.degree. C. to 700.degree. C. in the inertia force separator to form a partially dedusted combustion gas with a solids content of 5 to 40 g/Nm.sup.3 ; mixing the partially dedusted combustion gas with CaO and/or Ca(OH).sub.2 and optionally CaCO.sub.3 to form a gaseous mixture; providing a circulating fluidized bed device including a fluidized-bed reactor (8) and a downstream solids separator (7) with a return line (17) to the fluidized-bed reactor (8), the solids separator (7) being either another electrostatic precipitator or a bag filter; feeding the gaseous mixture and water into the fluidized-bed reactor (8); cooling the gaseous mixture in the fluidized-bed reactor (8) to a temperature of 50.degree. C. to 90.degree. C.; withdrawing a solids-containing gas from an upper portion of the fluidized-bed reactor (8); feeding the solids-containing gas into the solids separator (7) to form separated solids and a cleaned gas; recycling one portion of the separated solids into the fluidized-bed reactor (8) and mixing another portion of the separated solids with the combustion gas.
摘要:
The waste materials are gasified in a circulating fluidized bed in a gasification reactor, which is supplied with oxygen-containing gas. A gas-solids mixture is withdrawn from the upper region of the gasification reactor and is fed to a separator. Dust-laden gas and separated solids are separately withdrawn from the separator and the separated solids are recycled at least in part to the lower region of the gasification reactor. Temperatures in the range from 700.degree. to 1000.degree. C. are maintained in the gasification reactor. The dust-laden gas which is withdrawn from the separator has a heating value of about 3000 to 6000 kJ/sm.sup.3 and is fed to a combustion chamber and is combusted therein at temperatures from 1200.degree. to 1900.degree. C. Liquid slag is withdrawn from the combustion chamber.
摘要:
Disclosed is a fluidized bed system which includes a fluidized bed reactor, a solids separator and a return line and serves to carry out exothermic processes in a circulating fluidized bed for large thermal capacities. Secondary gas is introduced into the reactor on a level which is at least 1 meter above the bottom of the reactor. The fluidized bed system is provided with one or more displacing bodies, which cover 40 to 75% of the bottom surface area of the fluidized bed reactor and have a maximum height that is equal to one-half of the height of the reactor to ensure a satisfactory transverse mixing of the oxygen-containing secondary gas and fuel in reactors having large dimensions.
摘要:
Disclosed is a process for burning cattle dung at a temperature of from 500.degree. to 780.degree. C., preferably from 650.degree. to 780.degree. C., in the presence of one or more aluminum-containing substances selected from the class consisting of bauxite, kaolin and aluminum compound-containing ash from furnaces for firing solid fuels. A major part of the alkalies contained in the cattle dung and a substantial part of the chlorine are retained in combined form in the resulting furnace ash.