On-line remediation of high sulfur coal and control of coal-fired power plant feedstock

A method for continuously removing sulfur compounds and non-combustibles from a continuous supply of high sulfur raw coal, prepared for immediate use as feedstock at a power generating plant, said method comprising the steps of:

• a) crushing the high sulfur content raw coal mixture to produce particles of dense high-sulfur compounds, ash forming compounds, and particles of less dense coal;
• b) removing a proportion of the particles of dense high-sulfur compounds and non-combustible compounds that produce ash by separating these from the particles of the less dense coal to reduce the total sulfur content to bring the remaining coal into compliance with environmental laws;
• c) determining the sulfur content of the cleaned coal;
• and
• d) automatically adjusting the particle size of the high-sulfur content coal mixture in dependence upon the sulfur content of the separated coal mixture.

Apparatus for cleaning a continuous supply of high sulfur raw coal comprising coal, high sulfur compounds and ash forming materials so as to maximize the economics of generating electric power therefrom, said apparatus comprising in combination:

• a) means for crushing high-sulfur raw coal supplied to the power plant;
• b) means for separating and removing the high sulfur compounds and minerals that form ash when heated from particles of less dense coal to reduce the sulfur-dioxide and ash in the exhaust from the burning of the cleaned coal;
• c) means for determining the sulfur content of the separated coal mixture;
• and
• d) means, responsive to the sulfur content determining process, for controlling the proportion of dense high-sulfur and ash-forming compounds which are separated and removed from the coal to produce the most economic, legally acceptable, continuous supply of coal for use in a power plant.

A centrifuge separator apparatus for continuously separating sulfur and ash forming compounds from a continuous supply of raw coal after crushing it to produce optimum size and shape particles for separation, said apparatus comprising, in combination:

• a) a rotating symmetrical tapered cylinder having a horizontal central axis and two ends, a first end being slightly smaller than the other end having an entrance for all product being processed, and a second having an outlet at the center thereof;
• b) means for supporting said cylinder for rotation about said cylinder's central horizontal axis;
• c) means for rotating said cylinder about the central axis;
• d) means for continuously supplying coal in particulate form to the entrance of said cylinder;
• e) means for receiving coal in particulate form from the exit of the cylinder;
• and
• f) means for receiving the non-coal particles from a series of exit ports around the tapered cylinder at the point of greatest diameter.

A centrifugal separator apparatus for continuously separating sulfur compounds and ash from a continuous supply of high sulfur content coal in particulate form, said separator apparatus comprising, in combination:

• a) a substantially rotationally symmetric drum element having a horizontal central axis and two ends, a first end having a first inlet at the center thereof and a second end having a first outlet at the center thereof;
• b) means for supporting said drum element for rotation about said central axis;
• c) drive means for rotating said drum element about said central axis;
• d) means for continuously supplying coal in particulate form to said first inlet of said drum element;
• e) means for continuously receiving coal in particulate form from said first outlet of said drum element;
• wherein said drum element further includes at least one second outlet, arranged at a greater radial distance from said central axis than said first outlet, for preferentially discharging sulfur compounds and ash having a higher density relative to coal.