Method and an apparatus for making a mineral melt

Abstract

An apparatus for the production of a mineral melt burns combustible material in the presence of inorganic material to form a melt. The apparatus includes a circulating combustion chamber which receives a fuel, pre-heated mineral material and a combustion gas, melts the mineral material and generates exhaust gases which are separated from the melt. The gases pass through an exhaust pipe to a conduit of a heat exchange system. The apparatus includes a quenching hood for quenching the exhaust gases by drafting a cooling fluid, such as ambient air, into the flow of exhaust gases around the exhaust pipe, and wherein the exhaust gases exit the exhaust pipe inside the hood.

1 . A method of making a mineral melt, the method comprising the steps of:
 providing a circulating combustion chamber;   injecting fuel, particulate mineral material and combustion gas into the circulating combustion chamber;   combusting the fuel in the circulating combustion chamber thereby melting the mineral material to form a mineral melt and generating exhaust gases;   separating the exhaust gases from the mineral melt, collecting the mineral melt and passing the exhaust gases upwards through an exhaust pipe to a conduit of a heat exchange system; and   quenching the exhaust gases before entering the conduit by drafting a cooling fluid into the flow of exhaust gases around the exhaust outlet, wherein the exhaust outlet extends upwards from the combustion chamber at a height of at least 2.5 times the inner diameter of the exhaust pipe and into a quenching hood so that the exhaust gases exit the exhaust pipe inside the hood.   
     
     
         2 . A method according to  claim 1 , additionally comprising the step of making mineral fibres from the mineral melt by flowing the collected mineral melt through an outlet in the circulating combustion chamber to a centrifugal fiberising apparatus and forming fibres. 
     
     
         3 . A method according to  claim 1 , in which the exhaust gases leave the circulating combustion chamber at a temperature of between 1500 and 1900° C., and are then quenched to a temperature of from 1000 to 1500° C. 
     
     
         4 . A method according to  claim 1 , wherein the step of quenching is performed by the quenching hood which comprises an annular air intake opening around the exhaust pipe. 
     
     
         5 . A method according to  claim 1 , wherein the exhaust pipe is screened by a perforated screening element where the exhaust gases exit the pipe. 
     
     
         6 . An apparatus for the production of a mineral melt by burning combustible material in the presence of inorganic particulate material and thereby forming a melt, said apparatus comprising:
 a circulating combustion chamber for receiving a supply of a fuel, pre-heated mineral material and a combustion gas and combusting the fuel in the circulating combustion chamber thereby melting the mineral material to form a mineral melt and generating exhaust gases, wherein the apparatus is configured and operative so that the exhaust gases are separated from the mineral melt and the exhaust gases are passed upwards through an exhaust pipe to a conduit of a heat exchange system; and   quenching means for quenching the exhaust gases at the exhaust pipe,   characterised in that   the quenching means comprises a quenching hood for quenching the exhaust gases before entering the conduit by drafting a cooling fluid into the flow of exhaust gases around the exhaust outlet, and wherein the exhaust pipe extends upwards from the combustion chamber at a height of at least 2.5 times the inner diameter of the exhaust pipe and into the quenching hood so that the exhaust gases exits the exhaust pipe inside the hood.   
     
     
         7 . An apparatus according to  claim 6 , wherein the quenching hood comprises an annular air intake opening around the exhaust pipe. 
     
     
         8 . An apparatus according to  claim 6 , wherein the exhaust pipe has a larger diameter than the diameter of at least the inlet portion of conduit. 
     
     
         9 . An apparatus according to  claim 6 , wherein a perforated screening element is provided on the exhaust pipe. 
     
     
         10 . An apparatus according to  claim 6 , wherein the heat exchange system for pre-heating mineral material comprises a first pre-heater cyclone, a conduit for transporting exhaust gases from the circulating combustion chamber to the first pre-heater cyclone, a material inlet for injecting the mineral material into the conduit, and a flow communication from the first pre-heater cyclone to the circulating combustion chamber for feeding pre-heated mineral material to said combustion chamber. 
     
     
         11 . An apparatus according to  claim 6 , wherein the heat exchange system additionally comprises a second pre-heater cyclone, a second conduit running from the first pre-heater cyclone to the second pre-heater cyclone for transporting the exhaust gases, and a mineral material inlet for injecting the mineral material into the second conduit, wherein the mineral material conduit leads from the second pre-heater cyclone to the first conduit. 
     
     
         12 . An apparatus according to according to  claim 11 , wherein the apparatus further comprises a multi cyclone, a third conduit running from the second pre-heater cyclone for transporting exhaust gases to the multi cyclone, and a conduit for supplying separated material from the multi cyclone to the outlet of the first pre-heater cyclone.