Test bum

In 1991, Goodyear began working with Cadence Environmental Energy (Indiana) to market a whole tine feed system to supplement fuel for cement kilns. The system is used by several cement manufacturers. In 1992, Goodyear furnished tines for a Tennessee Valley Authority (TVA) test bum at a Memphis power plant. The electric utiUty used tine-derived fuel (TDE) to supplement coal fuel in a cyclone boiler. These tests were successflil. 

Another furnace that does not require fuel preparation is the stoker boiler, which was used by New York State Electric Gas Corporation (NYSEG) in its TDE tests. At NYSEG, the stoker boiler, which has a 1649°C (3000°E) flame temperature (as does the cyclone boiler), has routinely blended low quaUty coal, and more recently, wood chips with its standard coal to reduce fuel costs and improve combustion efficiency. In the tire-chip tests, NYSEG burned approximately 1100 t of tire chips (smaller than 5x5 cm) mixed with coal and monitored the emissions. The company determined that the emissions were similar to those from burning coal alone. In a second test-bum of 1900 t of TDE, magnetic separation equipment removed metal from the resulting ash, so that it could be recycled as a winter traction agent for roadways. 

De-wiring increases the costs of energy recovery by 25-50% (Amari et al. 1999). Some power companies have also conducted successful test bums with crumb-rubber TDF in their pulver-ized-coal boilers (Jones 1998). 

However, test bums that were conducted at a single facility to study the effects of adding TDF to a base fuel reveal chemical trends that may be similar to those observed at other facilities, and thus could be useful for assessing ash disposal and groundwater protection strategies. 

Table 7 lists the results of test bums at two coal-combusting power plants a western Kentucky power plant, which burned pure Illinois Basin coal (Table 4) and two blends of this coal + TDF (99 wt% coal + 1 wt% TDF 97 wt% coal + 3 wt% TDF) in a cyclone boiler (Hower et al. 2001) and the Purdue University power plant, which used a stoker boiler to combust a comparable Illinois Basin coal as well as a blend containing 95 wt% of this coal and 5 wt% TDF (Table 4 this study). 

Average of three analyses of TDF. used in test bum conducted by the Purdue University power plant (this study). 

TDF mixture was distinctly richer in S03, Zn, Ge, and As than the fly ash from pure coal. Most pronounced are the changes in the contents of S03 and Zn, which increased by factors of more than 2 and 16, respectively (Fig. 6). This result can be explained by the average concentrations of these volatile components in the two fuels used in the test bum the coal + TDF blend contains 2.1 wt% S and 183 ppm Zn, whereas the pure coal only contains 1.5 wt% S (Table 4) and 36 ppm Zn (Giere, unpublished data). The levels of most other analysed trace metals in the bulk fly ash decreased with the addition of TDF. For the bottom ash, many of... 

Overall, the Kentucky and Purdue studies show similar trends. The most important change resulting from the addition of TDF to coal is the increase in the Zn content of the fly ash. In contrast, most other trace elements have lower concentrations in the fly ash resulting from the combustion of the blend. Despite many similarities, two notable differences between the two test bums are observed. S03 and Pb showed opposite trends in the Purdue fly ash compared to the Kentucky fly ash. In both studies, enrichments of many trace elements... 

Below, we discuss test bums in industrial facilities that combusted both pure coal and coal/TDF blends. These fuels were burned at identical conditions in each combustor a stoker boiler at the University of Iowa (EPA 1997 Schwarzhoff Milster, personal communication 2003), a stoker boiler at Purdue University (this study), and two different cement kilns (Carrasco et al. 1998 Mukheijee et al. 2003). 

The University of Iowa conducted test burns with three different fuels (pure coal, and coal/ TDF blends of 96/4 wt% and 92/8 wt%), whereas the Purdue University study compared pure coal and a coal/TDF blend of 95/5 wt% (Table 8). In the Iowa test bum results, it is noted that the 96/4 wt% blend did not produce data that are entirely consistent with the trend exhibited by the blend containing 8 wt% TDF. This inconsistency is probably due to heterogeneity within each of the two fuel components or due to insufficient mixing of the two fuels. The Purdue data correspond both qualitatively and quantitatively more closely with the 8 wt% TDF Iowa data than they do with the 4wt% TDF data (Figs 7 and 8 Table 8). Both the University of Iowa and the Purdue University... 

The main noneconomic barriers to scrap tire combustion are the time required for permitting a plant and the concerns of neighbors regarding environmental, health, and safety issues. Because of the test bums required and time delays in permitting, many cement plant and pulp and paper mill operators hesitate to change their operation for the small savings realized by burning scrap tires. 

There is a similar situation with pulp and paper mills attempting to burn tdf. Generally, state and local officials have required test bums to ensure that emissions are within regulatory limits. Since tdf burned in pulp and paper mills tends to increase the particulate emissions somewhat, the permits sometimes restrict the percentage of tdf that may be burned. 

EPA is currently collecting existing environmental emissions data from facilities incinerating tires for energy purposes. This information can be compared to data on emissions from these same facilities when using conventional fuels such as coal and hog fuel. Several states and industrial facilities have been conducting test bums of tire-derived fuel, to gather this environmental data. 

Centex Itllnole Cenent Co. LaSelle, IL 1 dry kiln PH FF coal fired. Test use anticipate 6/91 test bum Applied for teat bum penalt plant 6/91 test bum. Cospleted penalt application plans April 1991 test bum. References 2 and 9... 

Eaeroc Materlala, Inc. Nazareth, PA 1 planned dry kiln PC to be completed 1991 Test bum In Novenber References 2, 5, and 7... 

Each incinerator test burn is unique and specific to the regulation being addressed. Each component of the test bum is determined by the test objectives and is unique from sampling requirements to test methods to data reporting, and is in many cases all or in part determined by the specific regulation.8... 

Up to now, the common assessment method of the hazards of solid oxidizers is merely burning rate tests of mixtures of oxidizers and wood powder or cellulose. For the burning rate tests of combustible solid particles, the following methods are used the IMO method (proposed by UK), the Rutubo method, the TNO methed, the US method, the US Transport Ministry method, the US Bureau of Mines method, the UK time/pressure test, and the modified time/pressure test. We have studied the IMO method, the TNO method and the modified time/pressure test. Bum hazards were described in the first book 1) and in Section 3.5 of this book. 

Within the scope of a research project [3], the prEN and ISO/DIS draft type test standards, especially the methods for determination of the efficiency and the measuring of the emissions, were compared with a continuous burning appliance by the Center of Appropriate Technology, Langenbruck. The efficiencies evaluated by both methods vary only marginal at all tested bum rates. The differences are within the accuracy range of the said test methods. The same is true for emission measuring methods. The measurements show that the test method with direct determination (calorimeter room) and the indirect determination (flue gas) of the efficiency can be considered as equivalent (Fig. I) The same can be concluded for the measurements of emissions in the flue gas and the dilution tunnel (Fig. 2). Provided that the test procedures are identical for both standards, equivalent results for efficiencies and emissions are obtained. 

In the following, experimental results of gas concentration measurements at the positions 6, 9 and 11 wilt be shown and discussed. All measurements are done at nominal heat output using suction probes covering the whole depth of the burnout zone. During one test bum cycle the suction probe remains at one position in order to get information about the course of gas composition and temperature at the particular measuring position. 

Therefore, it is important to take into account that a comparison of measured gas concentrations at three different measuring positions results in a comparison of data from three different burn cycles. Due to small differences among single test bum cycles the discussion is focussed on a more qualitatively evaluation of the obtained results. 

During the winter of 1991, bulk mustard was drained from preheated (20°C) 1 ton containers into heavy-walled, polyethylene-lined cardboard boxes and allowed to freeze under cool conditions (<0°C). The boxes containing frozen mustard were then placed in sealed metal cargo containers and immediately transported to the incinerator site. The boxes were then off-loaded and processed via the rotary kiln solids feed system. All bulk mustard (3 tonnes) was destroyed in this manner as part of the incinerator test bum program (see below). 

Aged and thickened mustard (9 tonnes) contained in nonexplosive ordnance items was destroyed following approval of the test bum results. Ordnance was punctured with small explosive perforating charges under cold conditions, sealed with adsorbent (vermiculite) in cardboard boxes and incinerated. The clean ordnance items were recovered from the ash discharge system and sold to a foundry for melting into recyclable metal. 

Two separate test bums were conducted in accordance with the EPP to demonstrate that project emission limits could be met. First, sulfur hexafluoride (SF ), a thermally-stable surrogate, was injected and burned to optimize operating conditions and demonstrate thermal destruction efficiency and acid gas removal capabilities. Batches of frozen mustard were then processed under the optimized conditions to establish system performance for regulatory approval. The SF6 and mustard test bum results are summarized in Table 6.3. 

Test Bum 2 results are based on averaged stack sampling and continuous stack emission monitoring system data from four separate tests conducted under optimized conditions. 

Mustard and contaminated scrap were incinerated out over a ten month period following approval of the test bums. During this time, the system availability averaged 55%, well below the industry average of 70 to 75% for solid waste incinerators. The prime cause was the need to perform frequent repairs to the refractory lining as a result of abrasion and impacts from the scrap metal feedstock. When operating, the system capably maintained stack emissions well within project limits and no stack excursions occurred while processing bulk mustard. 

Tampa Electric Company. 2002. Biomass Test Bum Report Polk Power Station Unit 1. Report to NETL-USDOE. April. 

This section describes several test bums and applications of TDF in cyclone-fired boilers. Cyclone boilers are well suited for TDF t plicaficms because they easily handle chipped material and the ash is mainly taken out in fluid form. Thus the additional steel is less of a problem in cyclones than in ccmventitnial pulverized-coal boilers. 

In the early 1990s, Ohio Edison completed a four-day scrap tire test bum of cofiring whole scrap tires and pulverized coal [34, 35]. Testing was done at the Toronto Plant, located in Toronto, Ohio. This facility is a 162 MWn plant with three generating units still in service. TDF testing was done in Unit 5, a 42 MWn B W pulverized coal-fired wet slag bottom boiler. The boiler was modified to accept whole scrap tires. 

The environmental results from the test bum showed that no permit requirements were violated. Con aring the baseline to the 20% tire (energy basis) cofiring test showed lead emission rates were 5% lower and particulate emissions rates were 28% lower. Based on the coal bunkered e last two days of the test at the 20% cofiring rate, the sulfur dioxide emission rate was 13.7% lower than the calculated expected value. Ohio Edison obtained a modification of its operating permit to include up to 20% of total boiler heat input from tires. At this rate, over three million scrap tires could be converted to electricity each year at the Toronto facility. 

The mechanical results of the test bums showed the equipment performed according to design. Tire feed rates varied from one tire every 34 seconds to one tire every 10 seconds during the test. To prove the mechanical aspects of the delivery system a brief test was conducted with a feed rate of one tire every 7 seconds. However, with some minor mechanical changes and additional fine-tuning of the programmable logic... 

For the incineration of hazardous waste, three performance standards have been set Organic wastes must be destroyed with an efficiency of 99.99 percent gaseous hydrogen chloride (e.g., from the incineration of PVC scrap) must be reduced 99 percent or to less than 4 lbs per hour, and particulate matter emissions may not exceed ISOmg per dry cubic meter of stack gas. The EPA requires test bums on all incinerators to ensure that these conditions are met, a major expense costing companies up to 100,000 for each unit. 

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