Apparatus for precipitating and separating a material in a solid form from a gaseous mixture

Apparatus for precipitating and separating a material in solid form from a gaseous mixture comprising:

• an elongated vessel having a gas inlet connection at one end and a gas outlet connection at the other end;
• at least one cooling coil for conveying a cooling fluid, said cooling coil extending along at least a portion of the length of the vessel and being attached to a wall of the vessel;
• at least one heating coil for conveying a heating fluid said heating coil extending along at least a portion of the length of the vessel and being attached to a wall thereof, said coils being wrapped around the exterior of the vessel, with the convolutions of the cooling coil alternating with the convolutions of the heating coil and arranged to convey their fluids in counterflow relation, each of said coils including a controllable bypass by means of which the fluid being conveyed may be bypassed around a portion of the respective coil, said portion being less than the entire length of the respective coil, and a connecting pipe line provided with a flow-regulating element and connecting the two coils at a location intermediate their ends a fluid supply line connected to one end of each coil and a fluid discharge line connected to the other end of each coil, the controllable bypass for each coil including a valved bypass line connected between the respective supply and discharge lines and valved branch lines connecting spaced-apart locations along the length of the bypass line with spaced-apart locatons along the length of the respective coil.