Low emissions process and burner

A process for reducing the sulpher and nitrogen emissions during coal combustion comprising:

• mixing together an uncalcined sorbent selected from the group consisting of alkaline and alkaline earth metal carbonates, bicarbonates, oxides and mixtures thereof and coal;
• pulverizing said coal-sorbent mixture prior to combustion whereby the average particle size of said coal-sorbent mixture does not exceed 75 microns, mixing said sorbent and coal in proportions to provide a metal in the sorbent to sulphur in the coal stoichiometric ratio of at least 1, combusting said mixture under staged air conditions to provide favorable sorbent calcining conditions and to favor low NO.sub.x emissions by control of combustion temperature and coal-air stoichiometry, wherein said staged air conditions comprise primary, secondary, and tertiary air streams wherein said primary air stream provides between about 10% to about 30% of the stoichiometric air required to combust the coal, said secondary air stream provides about 40% to about 100% of the stoichiometric air required to combust the coal, said tertiary air supplies the balance of the stoichiometric air required to combust the coal, plus an excess of between about 25% to about 40%, controlling said combustion air whereby said primary air is preheated to a temperature in the range of about 150 degrees F. to about 160 degrees F., said secondary and tertiary air streams are preheated to a temperature in the range of about 400 degrees F. to about 750 degrees F.;
• and,
• combusting said mixture to simultaneously burn said fuel and calcine said sorbent so that sulphur being evolved from the fuel during the combustion process will be adsorbed by said calcined sorbent.