Method for flame control in a rotary lime kiln

A rotary lime kiln comprising:

• a tubular lime kiln body having a first, lower end comprising a burner and a second, upper end adapted to receive lime to be burnt in the rotary lime kiln, the rotary lime kiln having a top part and a bottom part, said burner comprising a fuel pipe and a primary air pipe for providing air and fuel to the burner, said lime kiln further comprising a secondary air inlet admitting secondary air via a product cooler into the lime kiln at the first, lower end
• wherein a boost gas injector is arranged in a vicinity of the first end for admitting boost gas into the lime kiln, said boost gas injector comprising a boost gas pipe and a boost pipe outlet arranged to direct its boost jet gas stream in a direction towards the second end in the bottom part of the lime kiln.

A method for controlling flame stability in a rotary lime kiln comprising a tubular lime kiln body having a first end comprising a burner and a second end adapted to receive lime to be burnt in the rotary lime kiln, the rotary lime kiln having a bottom part and a top part, said lime kiln further comprising a fuel pipe and a primary air pipe for providing air and fuel to the burner, said lime kiln further comprising a secondary air inlet admitting secondary air into the lime kiln at the first, lower end and upstream of a mixing zone of the burner where outlets of primary air and fuel are located, wherein a boost gas injector comprising a boost gas pipe and a boost pipe outlet is arranged in the vicinity of the first end for injecting boost gas into the lime kiln, said boost jet gas stream being directed along or inclined relative the axial direction wherein boost gas is injected create a boost jet gas stream in the bottom part of the lime kiln between the flame from the burner and a product bed in the rotary lime kiln so as to produce a lower pressure in the bottom part of the lime kiln suppressing the flame to move towards the wall of the lime kiln in the top part.