Gravitational settling chamber o Used to remove particles with size greater than 50 μm. o Velocity of flue gas reduced in large chamber. o Particles settle under gravitational force. o The particulate matter is settled by its own weight by lowering the flue gas velocity.

نمایی از ته نشین کننده های ثقلی

راه بندها در این روش از صفحات راه بند به منظور کاهش سرعت ذرات و ته نشینی آنها استفاده می شود. راه بندها می توانند به دو صورت تر و خشک مورد استفاده قرار گیرد. در هنگام کاربرد راه بندهای تر علاوه بر ذرات، برخی گازهای آلاینده نیز حذف می گردند.

نمونه هایی از راه بندها

Vs= hV/L eq- i L= length of chamber V= horizontal velocity of carrier gas Vs= settling velocity of particulates h= height through which particulates travel before settling down

By stokes law Vs= g(ρ p - ρ)D 2 /18μ (ii) eq- ii D= diameter of particle g= acceleration due to gravity ρ p = density of particle ρ = density of gas μ= viscosity of gas

From eq- i and ii D= [18Vhμ/ Lg (ρ p - ρ)] 1/2 D = is minimum size of particle that can be removed in a settling chamber

Advantages o Low initial cost. o Easy to design. o Low pressure drop. o Low maintenance cost. o Dry and continuous disposal of solid particulates. Disadvantages o Require large space. o Less collection efficiency. o Only larger size particles can be collected.

Application o Industrial application is limited. o Used widely for removal of large solid particulates from draft furnace, kilns. o Sometimes used in process industry, food and metallurgical industry. o Used as pre-cleaners for high efficiency collectors. o Require simple maintenance