Technology Description: The Spouted Bed Reactor (SBR)

technology utilizes the unique attributes of the “spouting ” fluidization regime, which can provide heat transfer rates comparable

to traditional fluid beds, while providing robust circulation of

highly heterogeneous solids, concurrent with very aggressive

comminution (particle size reduction through abrasion.) The primary spouted bed provides a zone for volatilization, pyrolysis,

and gasification reactions. The gaseous products can then be

applied to highly efficient oxidation/incineration in conventional

combustion equipment, used for power production in prime movers or, alternatively, chemical products can be recovered. Thus,

gasification provides much greater opportunity for product recovery through Advanced Recycling.

The EER pilot plant process flow is shown in Figure 1. Waste is

fed into the primary spouted bed reactor via conveyor belt to the

extrusion feeder. The extrusion feeder is a very rugged screw

type extrusion device which extrudes the heterogeneous feed

material into the spouted bed thermochemical reaction zone

where solids are comminuted and gasified at medium temperature (1000-1600 °F). Large solids remain in the bed until they are

reduced in size through attrition, pyrolysis, and gasification reactions.

Steam and gaseous products elutriate fine particles out of the

primary reactor into the secondary slagging hot cyclone where

the temperature is increased significantly by addition of oxygen.

Fifty to 75% of the solids may be recovered as a vitrified product

from the slagging hot cyclone when it is operated at slagging

temperatures. The gas stream is then cooled via heat exchange

to recover heat and raise steam for the process and the fine

particulate is then removed in a traditional baghouse. Dry scrubbing techniques are used to remove acid gases. Baghouse ash

may be recycled to the primary spouted bed.

Steam is used as the spouting fluid, highly superheated by a

small in-line oxy-fuel burner. The resulting high velocity spouting

gases cause aggressive size reduction of heterogeneous feedstocks concurrent with the promotion of thermochemical gasification reactions. Particle size is rate limiting for heat and mass

transfer reactions, including pyrolysis and carbon gasification.

Therefore, rapid size reduction through comminution in the spouted

bed significantly improves reaction rates resulting in greater

throughput for a given equipment size. Superheated steam provides heat for endothermic pyrolysis reactions, along with partial

oxidation of wastes which react with sub-stoichiometric levels of

oxygen injected into the spouted bed primary.

EPA/540/F-93/XXX

August 1993

Emerging Technology Bulletin

Spouted Bed Reactor

Energy and Environmental Research Corporation

United States

Environmental Protection

Agency

Fines Injection

Secondary 02

EER

Spouted Bed

Technology TRW

Slagging

Technology

Slagging Cyclone

Syn-Gas

Product

Steam

Inert Granular Solids

02

Waste Feed

Extrusion Feeder

Spouted Bed

Reactor (SBR)

Rocket

Burner

Assembly

Tramp Metals Removal

Advanced recycling technology development

Steam

Steam

02

CH4

Figure 1. SBR thermochemical waste recycling system.
A secondary hot cyclone is fired with additional oxygen to further

raise the temperature of gasification products to slagging temperature when a vitrified product is desired. In the presence of

excess steam at high temperature, toxic organic compounds that

may result during low or medium temperature waste pyrolysis are

reduced to H2

, CO, CO2, and H2O. Subsequent purification of the

H2

/CO/CO2 gas stream can be accomplished using conventional

particulate and scrubbing technologies.

Waste Applicability: The SBR Advanced Recycling technology is primarily applicable to waste with significant heat content

that are contaminated with toxic organic compounds and heavy

metals. The heat content of the waste may range from 3,000 to

12,000 Btu per pound. Soils contaminated with coal tar residues,

petroleum refinery wastes, and municipal solid wastes are appropriate for processing in the SBR Advanced Recycling system.

Chemical waste, munitions and rocket propellants are also candidate feed materials.

Pilot Plant Test Results: Accomplishments to date have

included the design, construction, shakedown, and preliminary

operation of a pilot scale SBR facility capable of processing 1000-

1500 lb/hr of waste. Trouble-free feeding of “raw” unsegregated

Auto Shredder Residue (ASR) plastics has been accomplished at

a feed rate of 1400 lb/hr. Limited data obtained during test runs

have demonstrated the conversion of ASR to hydrocarbon rich

process gas (330-480 Btu/scf), with negligible tar formation, and

with 1-2% carbon remaining in the ash constituents. ASR product

ash analysis (recovered from the hot cyclone) indicated metals

leachability below regulated limits; lead and cadmium, the two

metals of primary concern in ASR, were 0.4 & 0.06 mg/l respectively, the limits being 5.0 and 1.0.

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/540/M5-93/50X

Preliminary tests with ASR have been limited to several short

duration runs, and some further modification and testing is required in order to complete the development of the SBR gasification technology and to demonstrate its effectiveness at pilot

scale. Later phases of development will then focus on issues

related to in-process and back-end clean-up of the product gas.

Advanced recycling (thermochemical conversion) of high Btu

content wastes can generate a variety of end products. These

include pyrolysate liquids, olefins, and syn-gas. EER’s SBR technology can be operated at low, medium, or high temperature in

order to generate these respective end products. Bed materials

tested to date include 1/16" and 1/4" silica sand, 1/4" alumina

balls, and 1 mm steel shot. The effects of bed materials and

reactive additives will require careful characterization.

For Further Information:

EPA Project Manager

Teri Richardson

US Environmental Protection Agency

26 West Martin Luther King Drive

Cincinnati, Ohio 45268

(513) 569-7949

EER Project Manager

Donald G. Taylor

Energy and Environmental Research Corporation

18 Mason

Irvine, CA 92718

(714) 859-8851