PORTABLE PILOT TEST UNIT. Mike Hill Shirco Infrared Systems, Inc.

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1 PORTABLE PILOT TEST UNIT BY Mike Hill Shirco Infrared Systems, Inc. DESCRIPTION The SHIRCO Portable Pilot Test Unit (Figure 1) was developed in response to the U.S. EPA Hazardous Waste Management Regulations ("RCRA regs"). These regulations have made transport of hazardous materials to SHIRCO's Pilot Test Facility in Dallas, Texas, difficult and expensive. It was determined that the market existed for a trailer-mounted waste disposal system, which could be brought to waste-producing or waste storage sites for thermal process testing. The construction and process functions of the furnace are identical to the full-scale Infrared Furnace. The Portable Pilot Test Unit is designed to demonstrate the performance of the Shirco Infrared Furnace in a variety of thermal processing applications. The system consists of a feed metering system, infrared primary chamber, a combination gas-fi red/infrared secondary chamber, and offgas hand1 ing, data acquisition and control systems and heating element power centers (HEPC's), all enclosed in a 45'0" van trailer. Material to be processed is fed by bucket or inclined conveyor onto a metering conveyor located at the feed end of the furnace through a conveyor or by manual dumping. A permanent feed conveyor system was not included in the system to allow maximum flexibility in the manner of transporting feed materials to the furnace. This is especially critical in remote areas where extensive feed perparation is not practical. The metering belt is synchronized with the furnace conveyor to control the material feed rate. The metering system includes a feed material hopper mounted over ti conveyor belt. The conveyor is shrouded and equipped with rubber skirts to minimize inleakage of air or escape of furnace gases. An adjustable guillotine-type gate is provided at the conveyor discharge. The gate distributes the material across the width of the metering belt and assists in furnace sealing. Final feed area sealing is provided by an additional adjcrstable knife gate in the feed chute into the furnace. The primary chamber consists of a rectangular cross section "box" of carbon steel lined with layers of ceramic fiber blanket mounted on stainless steel studs, and retained with ceramic fasteners. The material to be processed is conveyed through the furnace on a woven wire belt which is supported on high-temperature alloy shafts, The shafts are, in turn, supported by external flangemount bearings. A friction drive system is used to pull the belt through the furnace. When the material reaches the discharge end of the furnace, it drops off of the belt through a chute and into an enclosed hopper. The hopper contains a residue sampling drawer and seal gate, for collection of "grab'' samples of ash during processing. 65

2 Infrared energy is provided by transversely-mounted heating elements. The elements are silicon carbide rods, with external electrical connections at both ends. Access to the connections is gained by removing sheet metal wireway covers. The elements are grouped into two (2) control zones, with each zone being powered by a 10 KVA heating element power center (HEPC). The primary chamber has nominal external dimensions of 2.5 ft wide X 9.0 ft long X 7.0 ft high, and an installed weight of 3000 pounds. Its process capabilities include OF process temperature, with material residence time variable between ten and one hundred eighty minutes ( min). Oxidizing, reducing, or neutral atmospheres can be provided. The secondary chamber consists of a rectangular carbon steel box, lined with ceramic fiber blanket insulation. A propane-fired burner is used to ignite combustible gases present in the exhaust, and burn them at a predetermined setpoint temperature. An array of silicon carbide heating elements and a 10 KVA power center will be installed at a later date, to allow the chamber to serve as an elecrtic infrared afterburner. The chamber is sized to provide the required combustion residence time for the gases at setpoint temperature (typically 1.5 to 2.0 seconds). It has external dimensions of 3.0 ft wide X 9.0 ft long X 3.0 ft high, a weight of 1,500 pounds, and process capabilites of 2300 OF, two seconds (2 sec) gas residence time, and % excess air. The burner is mounted in the chamber end plate, with the flame pattern intercepting incoming primary chamber exhaust gases at a 900 angle. A continuous pilot and electronic flame monitoring are provided. Chamber operating temperature is controlled by adjusting the manual gas valve and air registers. Temperature is measured by a thermocouple located at approximately 1/3 of the chamber length from the burner outlet. Combustion air for the primary and secondary chambers is supplied by a blower with manual adjustment of airflow rate and distribution. A splitter manffald with dampers at the blower outlet allows control of airflow to both chambers. In the primary chamber, air is injected at various points along the length of the chamber through a manifold system. Adjustment of the flow to any injection point is by means of manual blast gate valves. In the secondary chamber, air is injected through the chamber top, directed at the interface of the burner flame pattern and exhaust gas inlet flow. Adjustment of flowrate is by means of a blast gate valve and the burner air registers. Exhaust gases from the secondary chamber pass through a venturi scrubber with a sump tank. This system consists of an adjustable venturi section containing water sprays, and a separator tower. A manual ly-adjustable cone-type damper is located in the venturi section is used to control scrubber pressure drop. The sprays in the venturi inject a fine water mist into the exhaust stream. The water droplets are sized to ''capture" particulate grains by having the

3 grains impact the droplets as they pass through the sprays. The larger and heavier water-covered particulate grains are then removed from the air stream in the separator tower by gravity, centrifugal force, and additional water sprays. In addition to removing particulate, the scrubber cools the gases from their incoming temperature (1OOOOF OF depending on system configuration) to saturation temperature, usually about 180OF. Subcooling to a lower temperature can be performed if required, but consumes substantially more water than cooling to saturation temperature. An induced draft exhaust blower is located on the discharge side of the scrubber. The blower is capable of exhausting the primary and secondary chambers, producing a slight (0.01 in. WC) draft on the system, while overcoming the 10.0 in. WC pressure drop of the scrubber. A vane-type damper is located on the outlet side of the blower. The damper provides a means of manually adjusting the induced draft gas flow. A removable exhaust stack is installed through the trailer roof. The stack extends 10 feet above the trailer roof, and is equipped with two standard EPA sampling ports. Access to the sampling ports is provided by scaffolding or a lift platform installed alongside the trailer. Standard EPA sampling ports are also provided in the primary and secondary chamber exhaust ducts for emissions testing. A master control panel contains the following control devices: Primary chamber heat zone temperature control lers Secondary chamber controller (electric mode only) Primary chamber belt speed controller Annunciator Hand-off-auto switches for mechanical components The annunciator provides alarms for the following mechanical and process conditions: Combusti on ai d stopped Primary chamber belt stopped Primary chamber belt mistracking Ai rlock stopped Comt!tstion blower off Exhaust blower off Heating element power center off Low exhaust draft Low scrubber water flow High primary chamber zone temperature The control panel contains the following devices for process data recording and monitoring: Mu1 ti -point temperature recorder Digital thermocouple reading display Furnace running time totalizer Primary chamber zone/secondary chamber power consumption totalizers 67

4 In addition, operating parameters can be monitored at the following system components : Ash hopper (material temperature) er (pressure drop) Scrubber venturi (water flowrate and pressure) r separator (water flowrate essure) Primary chamber exhaust (dvaft) Secondary chamber exhaust (draft) Heating elements in each of the two primary chamber zones are po KVA heating element power center to control the flow of electric heati ng el ements. Primary power t 12 KVA. As n ry chamber at B The first test of tapped step down A second test, ca nit's capability ermally fixing chr be safely landfil t e creates a car chromlun in a re offgases from th the facillty PO testing on the ash s levels of one percent (1%) of ave a1 rea@ been first two tests of exemption, respectively. r 68

5 U i t / t--t t-! COISUIIIOR AIM BLOW11 FIGURE 1 (Shircqlnc), ""I7 coo

6 TABLE I ON-SITE PILOT TEST - - INDUSTRIAL SLUDGE INCINERATION EMISSIONS TEST RESULTS Particulat rldsef 27.5 pp HCI.

7 ON-SITE PILOT TEST MUNICIPAL SLUDGE PYROLYSIS HEAVY METALS DATA Feed Ash Leachate Allowable ( mg /d r y k. g 1 (mg/l) Cadmium Chromium Lead Mercury

8 TABLE 111 PORTABLE PILOT TEST UNIT PERMITTING OPTIONS Non-Hazardous Materials Letter of Exemption Operating Exemption Permanent Permit Per mi t Modification Temporary Permit Hazardous Materials R,D,&D Permit Interim Status Mod w/part A Permit Facility Part A,B Special Exemption