Some of treatments of flue gas in steam boiler should be performed to reduce bad effect of emission (NOx and Sox) before distributed to atmosphere. The followings are treatment to reduce content of NOx and SOx
1. Treatment to reduce content of NOx
a) Select low content NOx of fuel such as for coal must less than 1.5%
b) Increase sizing of furnace to reduce temperature and NOx production.
c) Restrict the use of oxygen by low excess air when react with nitrogen to form NOx.
d) Use over fire air to add combustion perfectly.
e) Install flue gas filter such as multi cyclone, baghouse or electric precipitator to reduce NOx content in flue gas.
f) Use mechanical ash collection like hopper to collect unburned fuel.
2. Treatment to reduce content of SOx
a) Select low content of SOx fuel.
b) Use scrubber wet non regenerative, use additional chemical like limestone to react with SOx to be combined compound. The compound can be disposed or be sold for gypsum.
c) Use scrubber wet generative to make faster the process of collection by use sodium carbonate.
d) Use scrubber dry, collecting solid product result from heating process of flue gas, so dries up the moisture. The moisture can be taken from adding chemical in water based spray to flue gas.