Method and an apparatus for making a mineral melt
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 so as to melt the mineral material and generate 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. An apparatus for the production of a mineral melt by burning a combustible material in the presence of inorganic particulate material and thereby forming the melt, said apparatus comprising:
a circulating combustion chamber;
an exhaust pipe extending upwards from the circulating combustion chamber, the exhaust pipe having an inner diameter and a height, the height being at least 2.5 times the inner diameter;
a quenching hood disposed such that the exhaust pipe extends upwards into the quenching hood to define an annular air intake opening around the exhaust pipe; and
a heat exchange system having a first conduit and a first pre-heater cyclone, the first conduit connected to the quenching hood for transporting exhaust gases to the first pre-heater cyclone, wherein the inner diameter of said exhaust pipe is larger than an inner diameter of said first conduit.
2. An apparatus according to claim 1 , further comprising a perforated screening element on the exhaust pipe.
3. An apparatus according to claim 1 , wherein the heat exchange system comprises the first conduit, a material inlet in the first conduit, and a mineral material conduit extending from the first pre-heater cyclone to the circulating combustion chamber.
4. An apparatus according to claim 1 , wherein the heat exchange system additionally has a second pre-heater cyclone, a second conduit extending from said first pre-heater cyclone to the second pre-heater cyclone, and a mineral material conduit extending from the second pre-heater cyclone to the first conduit.
5. An apparatus according to according to claim 4 , wherein the apparatus further comprises a dust cyclone, a third conduit extending from the second pre-heater cyclone to the dust cyclone, and a conduit extending from the dust cyclone to an outlet of the first pre-heater cyclone.
6. An apparatus according to according to claim 1 , wherein the apparatus is operable to pass the exhaust gases through the exhaust pipe and into the first conduit of the heat exchange system.