INCINERATION TUTORIAL

INCINERATION TUTORIAL

AN EXCERPT FROM THE PROGRAM INCINER.BAS ON THE DISK TO ACCOMPANY BASIC ENVIRONMENTAL ENGINEERING, BY H.R. BUNGAY

EDITED FOR THE WORLD WIDE WEB BY GEORGE PENDLETON AND ANNA RUEPP


THIS TUTORIAL DISCUSSES INCINERATION AND THE VARIOUS TYPES OF INCINERATORS AVAILABLE ACCORDING TO PRESENT-DAY TECHNOLOGY. BY: JENNIFER LYNN REIDY DECEMBER 16, 1988

MARK OWENS MAY, 1990

JAMES M. WALDRON DEC., 1992


INCINERATION IS AN ENVIRONMENTALLY AND TECHNICALLY SUPERIOR METHOD OF WASTE DISPOSAL, OFFERING:

AT THE SAME TIME, IT IS HIGHLY CONTROVERSIAL AND EXPENSIVE. IN PREVIOUS DECADES, LANDFILLS WERE PRIMARILY USED FOR WASTE DISPOSAL, ALLOWING NATURE TO TAKE ITS COURSE, EVENTUALLY REDUCING THE END VOLUME TOXICITY OF THE WASTES. HOWEVER, BECAUSE OF INCREASINGLY STRINGENT ENVIRONMENTAL REGULATIONS CONCERNING AIR QUALITY, LANDFILLS, AND GROUNDWATER CONTAMINATION, ALONG WITH THE DECREASING AVAILABILITY OF LAND FOR THE ENCAPSULATION OF WASTES, INCINERATION HAS BECOME THE DESIRED DISPOSAL METHOD FOR MUNICIPALITIES AND INDUSTRIES.

YET, EVEN INCINERATION TECHNOLOGY IS CONSTANTLY UNDERGOING REVISIONS IN ORDER TO MEET TOUGHER ENVIRONMENTAL STANDARDS. THESE TECHNOLOGICAL ADVANCES INCLUDE THOSE THAT INCREASE EFFICIENCY, AND THOSE THAT USE EMISSIONS CONTROL APPARATUS.

INCINERATION THERMALLY DECOMPOSES MATTER THROUGH OXIDATION, THEREBY REDUCING AND MINIMIZING THE WASTES, AND DESTROYING THEIR TOXICITY. IT CAN BE APPLIED TO INDUSTRIAL, MUNICIPAL, AND HAZARDOUS WASTES, PROVIDED THAT THEY CONTAIN ORGANIC MATERIAL. SINCE IT IS PRIMARILY ORGANIC SUBSTANCES THAT CAN UNDERGO AND SUSTAIN THERMAL DEGRADATION.


AFTER INCINERATION, WASTES ARE CONVERTED TO:

DEPENDING ON THE COMPOSITION OF THE INITIAL WASTE, COMPOUNDS CONTAINING:

MAY BE PRODUCED. THESE COMPOUNDS, ALONG WITH CO, ARE DELETERIOUS TO THE ATMOSPHERE, AND HIGHLY REGULATED. PRESENTLY, THE DESTRUCTION EFFICIENCY FOR THESE HAZARDOUS WASTES MUST BE 99.9999 %. THUS, TO MEET REGULATIONS, INCINERATORS NEED TO BE EQUIPPED WITH:


TO PROVIDE SECONDARY TREATMENT FOR ENVIRONMENTALLY UNSAFE COMPOUNDS, SO THAT THEY CAN BE RELEASED TO THE ATMOSPHERE AT SUITABLE CONCENTRATION LEVELS. VARIOUS TYPES OF INCINERATORS ARE CURRENTLY MANUFACTURED. THE CHOICE OF AN INCINERATOR DEPENDS ON THE WASTES' COMBUSTIBILITY AND ITS CHARACTERIZATION AS LIQUID, SLUDGE, SOLID, OR GAS. THE WASTES' COMBUSTIBILITY CHARACTERISTICS, SUCH AS IGNITION TEMPERATURE, FLASH POINT, AND FLAMMABILITY LIMITS DETERMINE THE NECESSARY OPERATING TEMPERATURE, O2 CONCENTRATION, AND RESIDENCE TIME FOR GREATEST WASTE MINIMIZATION. THE PROPER INCINERATOR TYPES CAN THEN BE IDENTIFIED BASED ON THE WASTE SPECIFICATIONS. THE FOLLOWING ARE TYPES OF INCINERATORS:

OF THESE, ROTARY KILN, FLUIDIZED BED, AND LIQUID INJECTION ARE THE MOST, PREVALENT IN INDUSTRY BECAUSE OF THEIR, APPLICABILITY TO LARGE SCALE USE AND, AND THEIR VERSATILITY. CONSEQUENTLY, I WILL CONCENTRATE ON, THESE THREE KINDS.

ROTARY KILN CHARACTERISTICS:

FLUIDIZED BED CHARACTERISTICS:

LIQUID INJECTION CHARACTERISTICS:

ONE OTHER CHARACTERISTIC THAT ALL THREE TYPES OF INCINERATORS (ROTARY KILN, FLUIDIZED BED, AND LIQUID INJECTION) SHARE IS THAT THEY CAN ALL BE OPERATED IN A PYROLYSIS OR OXYGEN STARVED MODE. WASTES WITH HIGH CALORIC VALUE THAT ARE CAPABLE OF RELEASING GREAT HEAT CONTENT ARE MOST APPROPRIATE FOR THIS KIND OF OPERATION. THE OTHER TYPES OF INCINERATORS ARE DESCRIBED AS FOLLOWS.

MULTIPLE HEARTH INCINERATORS CONSIST OF VERTICALLY SHAPED HEARTHS, AND ARE PRIMARILY UTILIZED FOR SEWAGE SLUDGE. THEY ARE OPERATED FROM 1400-1800 F. CATALYTIC COMBUSTION, WASTE-GAS FLARE AND DIRECT FLAME INCINERATORS ARE ALL FOR GASES. CATALYTIC COMBUSTORS USE A CATALYST AND ARE DESIGNED FOR LOW ORGANIC CONCENTRATION WASTES. WASTE-GAS FLARES ARE USED FOR NON-HAZARDOUS WASTE THAT HAS HIGH ORGANIC CONTENT. DIRECT FLAME INCINERATORS OPERATE FROM 1000-1500 F AND ARE USED WHEN WASTE GAS CONTAINS PARTICLES.

ON A FINAL NOTE, ONE VERY CONTROVERSIAL FORM OF INCINERATION THAT PRESENTLY HAS BEEN BANNED IN THE UNITED STATES, BUT IS USED IN EUROPE IS OCEAN INCINERATION. FOR THIS,TWO INCINERATORS ARE MOUNTED ON A HUGE SHIP THAT CARRIES THE WASTES OUT TO THE MIDDLE OF THE OCEAN AND BURNS THEM OUT THERE.THE IDEAL WASTES FOR THIS KIND OF DISPOSAL ARE TOXIC AND HAZARDOUS WASTES SUCH AS CHLORINATED MATTER, PCB'S,AND ORGANOMETALLICS. OCEAN INCINERATION IS PERFECT FOR THESE WASTES BECAUSE THE ACIDS PRODUCED CAN BE NEUTRALIZED BY THE HUGE BUFFERING CAPACITY OF THE OCEAN. THIS ELIMINATES THE NEED FOR SCRUBBERS AND OTHER SECONDARY TREATMENT TO DETOXIFY THE COMBUSTION PRODUCTS AND MAKE THEM MORE ENVIRONMENTALLY ACCEPTABLE.


COMBUSTION INCINERATORS-OXYGEN USING SYSTEMS

KEY FEATURES OF A COMBUSTION INCINERATOR:


COMBUSTION STAGES


TYPES OF COMBUSTION INCINERATORS

1. MASS BURN-MOST COMMON

MINIMAL PREPROCESSING REQUIRED (NOT MUCH SIZING, SHREDDING, ETC.). MASS BURN INCINERATORS VARY IN SIZE. THEY RANGE FROM 100 TO 1000 TONS OF WASTE PER DAY. USE A GRATE SYSTEM TO MIX AND AGITATE THE WASTE AS IT TRAVELS THROUGH THE FURNACE TO PROVIDE COMPLETE COMBUSTION. AIR FOR COMBUSTION IS SUPPLIED BY FANS OR BLOWERS UNDER AND OVER THE GRATES.

THREE TYPES OF MASS BURN INCINERATORS (BASED ON ENERGY RECOVERY METHOD)

(A)WATER WALL FURNACE


(B)REFRACTORY FURNACE


(C)ROTARY KILN FURNACE