Waste fuel delivery to long kilns

• US 5,224,433 A
• Filed: 11/17/1992
• Issued: 07/06/1993
• Est. Priority Date: 11/23/1988
• Status: Expired due to Term

• Current Assignee: Cadence Environmental Energy Inc.
• Original Assignee: Cadence Chemical Resources, Inc., ASH Grove Cement Company (CRH PLC)
• Inventors: Reese, Theodore J., Hansen, Eric R., Benoit, Michel R.
• Primary Examiner(s): Favors, Edward G.
• Application Number:
  US07/978,154
• Time in Patent Office: 231 Days
• Field of Search: 110/346, 110/246, 110/238, 110/226, 110/237, 414/149, 414/199, 432/103, 432/105, 432/106
• US Class Current: 110/346
• CPC Class Codes: C04B 7/4407 Treatment or selection of the fuel therefor, e.g. use of hazardous waste as secondary fuel fuels in general C10L; Use of particular energy sources, e.g. waste hot gases from other processes
• CPC Class Codes: C04B 7/4423 Waste or refuse used as fuel
• CPC Class Codes: C04B 7/4438 the fuel being introduced directly into the rotary kiln
• CPC Class Codes: F23G 2203/206 with charging ports in the sidewall
• CPC Class Codes: F23G 2205/16 using chute
• CPC Class Codes: F23G 2206/201 with an industrial furnace
• CPC Class Codes: F23G 2207/101 for temperature
• CPC Class Codes: F23G 2900/52002 Rotary drum furnaces with counter-current flows of waste and gas
• CPC Class Codes: F23G 5/08 having supplementary heating
• CPC Class Codes: F23G 5/20 having rotating or oscillating drums
• CPC Class Codes: F23G 5/448 in which the waste is fed in containers or the like
• CPC Class Codes: F23J 2217/101 Baghouse type
• CPC Class Codes: F23J 2217/102 electrostatic
• CPC Class Codes: F27B 2007/3247 through a lateral opening in the drum
• CPC Class Codes: F27B 7/32 Arrangement of devices for charging
• CPC Class Codes: F27B 7/34 Arrangements of heating devices
• CPC Class Codes: F27D 2099/0051 Burning waste as a fuel
• CPC Class Codes: Y02E 20/30 Technologies for a more efficient combustion or heat usage
• CPC Class Codes: Y02P 40/125 Fuels from renewable energy sources, e.g. waste or biomass

Abstract

A method is described for environmentally sound usage of combustible hazardous waste in an operating rotary kiln. The method is particularly adapted for disposal of solid hazardous wastes, optionally in the form of a blended waste homogenate, Packaged in sealable containers. The containers are used as fuel modules and charged into a rotary kiln cylinder where kiln gas temperatures range from about 950° to about 1200° C. to achieve high destruction and removal efficiencies.

Claims

1. Method for charging combustible waste to a rotary cement kiln comprising a rotating kiln cylinder to burn said waste in contact with in-process mineral material, said method comprising the steps ofmodifying said cement kiln to provide a port in the rotary kiln cylinder at a point along its length where waste charged through the port will contact calcining mineral during kiln operation, said port having a closure moveable between a port-closed and a port-opened position;

2) positioning the waste in alignment with said port during rotation of the kiln cylinder;

3) moving the port closure to the port-opened position and charging the waste into the kiln through the port;

4) moving the port closure to the port-closed position; and

5) repeating steps 2-4 during kiln operation whereby combustible waste is used to provide up to 40% or more of the energy requirements of kiln operation.

4. The method of claim 1 wherein the closure for the port is sized and positioned to allow air flow into the kiln when the closure is in the port closed position.

5. The method of claim 1 wherein the port closure is moved to the port-opened position at a point during rotation of the kiln cylinder where the waste charged into the kiln through the port falls on top of the in-process mineral material in the rotating kiln cylinder.

6. The method claim 1 wherein the port is sized to permit passage of containers of waste into the operating kiln.

7. The method of claim 1 wherein the kiln is further modified to provide means for preventing the in-process mineral from contacting the port closure during kiln cylinder rotation.

2. Method for charging combustible waste to a rotary cement kiln comprising a rotating kiln cylinder to burn said waste in contact with in-process mineral material, said method comprising the steps of:

1) modifying said cement kiln to provide a port in the rotary kiln cylinder at a point along its length where waste charged through the port will contact calcining mineral during kiln operation;

2) modifying said kiln to provide a fuel receiving chute for aligning the waste with the port;

3) during kiln operation, locating the waste in the fuel receiving chute;

4) charging the positioned waste through the port into the rotary cylinder; and

5) repeating steps 2-4 during kiln operation whereby combustible waste is used to provide up to 40% or more of the energy requirements of kiln operation.

3. The method of claim 2 wherein the fuel receiving chute is stationary and in axial alignment with the port in the kiln cylinder.

8. The method of claim 2 wherein the positioned waste is charged through the port into the rotating kiln cylinder at a point during rotation where the charged waste falls onto the top of the in-process mineral material in the rotating kiln cylinder.

9. The method of claim 2 wherein the kiln is further modified to provide means for preventing the in-process mineral from escaping through the port during kiln cylinder rotation.

10. The method of claim 2 wherein the port and the fuel receiving chute are sized to permit delivery of containerized waste through the port during kiln operation.

11. The method of claim 2 wherein the fuel receiving chute is mounted on the rotary cylinder in alignment with the port.