Clean Energy from Waste and Coal - ACS Publications - American

Chapter 18

Analysis of Organic Emissions from Combustion of Quicklime Binder-Enhanced Densified Refuse-Derived Fuel—Coal Mixtures 1

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Russell Hill , Baushu Zhao , Kenneth E. Daugherty , Matthew Poslusny , and Paul Moore 3

Downloaded by CORNELL UNIV on July 25, 2016 | http://pubs.acs.org Publication Date: December 23, 1992 | doi: 10.1021/bk-1992-0515.ch018

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Department of Chemistry, University of North Texas, Denton, TX 76203 Department of Chemistry, Marist College, Poughkeepsie, NY 12601 Erling-Riis Research Laboratory, International Paper, Mobile, AL 36652 2

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Emission t e s t i n g f o r PCBs and PCDDs has been performed on the combustion gases produced by c o f i r i n g a quicklime binder enhanced densified refuse derived fuel/coal mixture. Analysis found that the PCBs were reduced i n the presence of the Ca(OH) binder and PCDD concentrations were below detection l i m i t s . Samples were obtained from the 567 ton, full scale, c o f i r i n g of bdRDF at various concentrations with high s u l f u r coal at Argonne National Laboratory, 1987. An EPA Modified Method 5 sampling t r a i n was used t o i s o k i n e t i c a l l y obtain samples p r i o r to and a f t e r p o l l u t i o n control equipment. A f t e r sample clean up, analysis was completed using low and high resolution GC/MS. In an attempt to correlate PCB and PCDD reductions with binder concentrations, calcium and chloride analysis were performed on feedstock, f l y ash and bottom ash samples. 2

Two of the nations current major concerns are municipal s o l i d waste and energy. The combustion of refuse derived fuel (RDF) i s increasingly being recognized as an a t t r a c t i v e alternative to both problems. On average 5 pounds of municipal s o l i d waste (MSW) per day i s being produced by each U.S. c i t i z e n . This waste cumulates to over 200 m i l l i o n tons per year, the majority of which i s disposed of i n l a n d f i l l s (1). Up u n t i l the formation of the Environmental Protection Agency (EPA) i n 1970, most of the l a n d f i l l s were simple open dumping grounds with l i t t l e control measures i n place. In the mid 1970 s under authority of the Resource Conservation Recovery Act, the EPA began shutting down open dumping and promoting sanitary l a n d f i l l s (2). Sanitary l a n d f i l l s are t y p i c a l l y huge depressions lined with clay to minimize 1

0097-6156/93/0515-0223$06.00/0 © 1993 American Chemical Society Khan; Clean Energy from Waste and Coal ACS Symposium Series; American Chemical Society: Washington, DC, 1992.


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p o s s i b l e l e a c h i n g i n t o the area groundwater. These l a n d f i l l s have g u i d e l i n e s d e t a i l i n g packing, c o v e r i n g , and monitoring procedures (3). Industry has r e c e n t l y begun t o pay a t t e n t i o n t o t h i s overwhelming problem and new products f o r containment and monitoring are c o n s t a n t l y being developed. However, a slow s t a r t has postponed i n d u s t r i a l s o l u t i o n s t o the d i s t a n t f u t u r e , while a t the same time, an i n c r e a s i n g l y concerned p u b l i c i s demanding immediate solutions. Between 1982 and 1987 approximately 3000 l a n d f i l l s were shut down without replacement (4) . The O f f i c e of Technology Assessment (OTA) p r e d i c t s t h a t 80% of i d l e l a n d f i l l s w i l l be c l o s e d w i t h i n twenty years (5). The "Not i n my Backyard Syndrome" (NIMBY) , has s i g n i f i c a n t l y c o n t r i b u t e d t o the decrease i n development of many new l a n d f i l l s i t e s . A c l a s s i c example of p u b l i c o p p o s i t i o n i s the 1988 Marbro barge i n c i d e n t . The barge c a r r i e d 3000 tons of garbage 6000 m i l e s down the e a s t e r n U.S. c o a s t l i n e l o o k i n g f o r a l a n d f i l l w i l l i n g t o accept i t s cargo (6). T h i s new found p u b l i c consciousness has f o r c e d l a n d f i l l s i t e s t o be p l a c e d f a r t h e r from p o p u l a t i o n c e n t e r s . The r e s u l t has been higher t r a n s p o r t a t i o n c o s t s . The northeastern s t a t e s , which have t r a d i t i o n a l l y exported garbage, are f i n d i n g i t i n c r e a s i n g l y d i f f i c u l t and c o s t l y t o f i n d anyone w i l l i n g t o accept the waste. Even s t a t e s with the p o t e n t i a l t o l o c a t e many new s i t e s are being c a u t i o u s i n response t o p u b l i c o p i n i o n . Texas, with i t s open space, awarded 250 permits per year i n the mid 1970s, but was down t o l e s s than 50 per year by 1988 (7) . S t r i c t e r r e g u l a t i o n s proposed by the EPA i n 1991 are expected t o e v e n t u a l l y lead t o a d r a s t i c c o s t i n c r e a s e of approximately 800 m i l l i o n d o l l a r s per year (8). These f a c t s , coupled with the p o t e n t i a l f o r l a r g e l i a b i l i t y c o s t s , have f o r c e d the MSW i n d u s t r y t o look f o r other prospective solutions. An obvious a l t e r n a t i v e t o l a n d f i l l i n g MSW is i n c i n e r a t i o n . Mass burn i n c i n e r a t i o n , where r e f u s e i s fed i n t o a furnace with moving g r a t e s a t temperatures of 2400°F, was a popular s o l u t i o n i n the 1970s. Increased a i r p o l l u t i o n , as w e l l as ground water contamination due t o l e a c h i n g of ash r e s i d u e , has c u r r e n t l y p l a c e d mass burning i n a s t a t e of d i s f a v o r . Mass burn i n c i n e r a t i o n a l s o tends t o be p r o h i b i t i v e l y expensive (up t o $400 m i l l i o n per f a c i l i t y ) (7,9). P o l l u t i o n produced by the combustion of MSW is c e r t a i n l y a j u s t i f i a b l e concern. However, i f a means f o r c o n t r o l l i n g emissions t o reasonable l e v e l s i s found, then another combustion product c o u l d be put t o good use ENERGY. The energy p o t e n t i a l of the 200 m i l l i o n tons of MSW produced annually i n the U.S. equals approximately 326 m i l l i o n b a r r e l s of o i l (9). T h i s renewable resource can only be tapped i f an environmentally acceptable a l t e r n a t i v e

Khan; Clean Energy from Waste and Coal ACS Symposium Series; American Chemical Society: Washington, DC, 1992.


18. HILL ET AL.

PCBs and PCDDs from bdRDF & Coal Combustion

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t o mass i n c i n e r a t i o n i s found. A promising a l t e r n a t i v e i s t h a t of resource recovery followed by i n c i n e r a t i o n . This process i n v o l v e s removing v a l u a b l e r e c y c l a b l e s such as cardboard, p l a s t i c s , g l a s s , metals, and compost m a t e r i a l s , a l l from a c e n t r a l r e c e i v i n g s t a t i o n . The c h i e f byproduct of t h i s process, c o n s i s t i n g p r i m a r i l y of paper, i s known as r e f u s e d e r i v e d f u e l (RDF). RDF has a energy value of about 7500 Btu/lb, s i m i l a r t o a high grade of l i g n i t e c o a l . I t can be c o f i r e d with c o a l u s i n g cement k i l n s or other c o a l burning f a c i l i t i e s . The two most common forms are RDF-3 or " f l u f f " and RDF-5 or " d e n s i f i e d " . F l u f f RDF t y p i c a l l y v a r i e s i n p a r t i c l e s i z e from a few inches f o r spread stoker b o i l e r s , down t o 0.75 inches f o r suspension f i r e d b o i l e r s . I t i s e i t h e r burned i n dedicated b o i l e r s or c o f i r e d with c o a l . There are a number of problems with f l u f f RDF. 1. I t tends t o compress under i t s own weight l i m i t i n g storage time. 2. I t s bulk d e n s i t y (2-3 l b / c u b i c foot) makes i t d i f f i c u l t t o t r a n s p o r t . 3. I f wet i t can decay r a p i d l y . 4. I t can be d i f f i c u l t t o d e l i v e r t o a furnace i n a c o n t r o l l e d manner. Many of these d i f f i c u l t i e s can be overcome by extruding f l u f f RDF to create 2-3 inch long by 1/4 inch i n diameter p e l l e t s of d e n s i f i e d RDF (dRDF). Densified RDF has a bulk d e n s i t y on the average of 35 l b s / c u b i c f o o t . Transportation, storage, degradation, and processing problems are a l l reduced by d e n s i f i c a t i o n . T y p i c a l l y dRDF p r o c e s s i n g begins on the p l a n t t i p p i n g f l o o r . Large items are removed from the waste and the remainder i s loaded onto conveyor b e l t s . The m a t e r i a l f i r s t passes through a r o t a r y drum s i e v e t o remove the f i n e s (mostly organic material) f o r composting. The m a t e r i a l i s then hand picked from the conveyor b e l t f o r r e c y c l a b l e s . Hammermills or g r i n d e r s reduce the m a t e r i a l in size. Next, f e r r o u s metals are removed m a g n e t i c a l l y . Air classifiers are used to separate the fine, predominantly paper m a t e r i a l from small p i e c e s of g l a s s , rock, e t c . which must be l a n d f i l l e d . The f r a c t i o n of m a t e r i a l r e q u i r i n g l a n d f i l l i n g i n an e f f i c i e n t p l a n t w i l l only amount t o about 10-15% of the t o t a l o r i g i n a l volume. The paper and p l a s t i c RDF i s now d r i e d t o the proper moisture l e v e l f o r d e n s i f i c a t i o n . Binders are o c c a s i o n a l l y added prior to d e n s i f i c a t i o n to increase physical d u r a b i l i t y and combustion performance. In 1985 the U n i v e r s i t y of North Texas (UNT), under c o n t r a c t with Argonne N a t i o n a l Laboratory, i n v e s t i g a t e d over 150 m a t e r i a l s as p o s s i b l e binders f o r dRDF. A binder was sought t h a t would improve p e l l e t integrity for t r a n s p o r t a t i o n and storage purposes. A sample of the


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m a t e r i a l s used investigated:

e x e m p l i f i e s the d i v e r s i t y


glues n a t u r a l starches urea formaldehyde s u l f i t e waste l i q u o r s beeswax f l y ashes animal adhesive limestone cement k i l n dust slags

of materials

carbon b l a c k urea r e s i n s epoxy r e s i n s weed a d d i t i v e gelatins asphalt roof t a r sludges p a i n t sludges cotton burrs P o r t l a n d cement

I n i t i a l l y , agents were s e l e c t e d based on expected a v a i l a b i l i t y , cost, environmental acceptance, and p o t e n t i a l binding a b i l i t y . Because o f cost, i t was f e l t t h a t the binder used with RDF should show cementitious bonding as opposed t o bonding n e c e s s i t a t i n g a high temperature operation. G e n e r a l l y , cementitious bonding involves i n o r g a n i c adhesive bonds h o l d i n g together an aggregate, such as a RDF p a r t i c l e . The adhesion r e s u l t s p r i m a r i l y from hydrogen bonding. T h i s type o f cementing p r o v i d e s p e l l e t s t h a t possess l i m i t e d p h y s i c a l s t r e n g t h but are durable f o r t r a n s p o r t a t i o n and long term storage. They are also resistant t o water a t t a c k and biodégradation. Advantages o f cementitious bonding i n c l u d e the f a c t s t h a t the cements can be poured o r gunned d i r e c t l y i n t o p l a c e . They cause l i t t l e o r no dimensional changes d u r i n g b i n d i n g , and they are r e l a t i v e l y inexpensive. The d e n s i f i c a t i o n technique w i l l remove the pores between the RDF p a r t i c l e s (accompanied by shrinkage o f the components), as a r e s u l t o f g r a i n f u s i o n and strong interactions between adjacent particles. Before d e n s i f i c a t i o n of RDF can occur, the f o l l o w i n g c r i t e r i a must be met. A mechanism f o r m a t e r i a l t r a n s p o r t must be present and a source of energy t o a c t i v a t e and s u s t a i n t h i s m a t e r i a l must e x i s t . The two primary mechanisms f o r heat t r a n s f e r are d i f f u s i o n and v i s c o u s flow. Heat i s the primary source of energy, i n c o n j u n c t i o n with energy g r a d i e n t s due t o p a r t i c l e - p a r t i c l e contact and s u r f a c e t e n s i o n . The d i f f e r e n c e i n f r e e energy o r chemical p o t e n t i a l between the f r e e s u r f a c e s o f RDF p a r t i c l e s , i s c r u c i a l t o the densification process. Diffusion properties, temperature, and p a r t i c l e s i z e are a l s o important. The 150 b i n d i n g agents were f i r s t screened based on c o s t and environmental e f f e c t s . Cost was weighted a t 60%, environmental e f f e c t s a t 40%. Environmental a c c e p t a b i l i t y , was f u r t h e r broken i n t o the 3 c a t e g o r i e s o f : t o x i c i t y 10%, odor 10%, and emissions 20%. The l i s t was reduced to 70 p o t e n t i a l binders i n t h i s manner. These b i n d i n g


18. HILL ET AL.


227

agents were analyzed i n a l a b o r a t o r y study broken i n t o 11 characteristics:


binder binder pellet pellet pellet pellet

Btu content binder d i s p e r s i b i l i t y a b i l i t y t o wet binder ash content water s o r b a b i l i t y p e l l e t caking i g n i t i o n temperature p e l l e t moisture content durability p e l l e t aerobic s t a b i l i t y w e a t h e r a b i l i t y (110/32°F)

The t e s t s were grouped i n t o two c l a s s e s , t h e f i r s t four c h a r a c t e r i s t i c s being binder p r o p e r t i e s and t h e l a s t seven characteristics being classified as pellet p r o p e r t i e s . The binder p r o p e r t i e s were weighted a t 7% p e r c h a r a c t e r i s t i c , and the p e l l e t p r o p e r t i e s were weighted as 4% p e r c h a r a c t e r i s t i c . Laboratory t e s t r e s u l t s produce the 13 top binders f o r f u r t h e r p r o c e s s i n g . The h i g h e s t ranked binders were: calcium oxide (CaO) calcium hydroxide (Ca(OH) ) dolomite Ca (OH) /dolomite cement k i l n dust P o r t l a n d cement CaO/dolomite/Portland Cement

bituminous f l y ash l i g n i t e f l y ash western c o a l f i n e s Iowa c o a l f i n e s Ca (OH) / l i g n i t e f l y ash calcium l i g n o s u l f o n a t e

2

2

2

Some observations t h a t can be made on t h e most e f f e c t i v e binders are (a) t h e binder must have l a r g e s u r f a c e areas, (b) the binders a r e b a s i c . The b a s i c binders (those u s i n g Ca(OH) ) are b e l i e v e d t o be e f f e c t i v e due t o : 2

(1) the calcium b i n d i n g agent breaks t h e RDF s u b s t r a t e down producing a by-product with a c i d i c groups such as a c a r b o x y l i c a c i d group cellulose

o x i d i z e s

> N[R-£oH]

> R-£-0-Ça

+ H0 2

(2) the calcium from the b a s i c binder r e a c t s i n a complex o r c h e l a t e formation mode with t h e a c i d i c groups of RDF (3) the calcium hydroxide produced by t h e b a s i c groups r e a c t i n g with moisture i n the RDF, o r present i n i t i a l l y i n t h e binder, g r a d u a l l y carbonates Ca(OH) + C0 2

plant

2

>

CaC0 + H 0 3

2

These f i n a l b i n d i n g agents were t e s t e d i n a p i l o t o p e r a t i o n performed a t the J a c k s o n v i l l e Naval A i r


228


S t a t i o n , J a c k s o n v i l l e , F l o r i d a i n the summer of 1985. The t e s t i n v o l v e d over 7000 tons of RDF, and p i l o t p l a n t experiments. Mixing processes and t e s t i n g procedures were p r e v i o u s l y p u b l i s h e d (10,11). Bulk d e n s i t y was used as an estimate of p e l l e t d u r a b i l i t y d u r i n g o n - s i t e t e s t i n g . Ca(OH) was found t o i n c r e a s e bulk d e n s i t y over a v a r i e t y of p e l l e t moisture contents and allowed p r e s s i n g of p e l l e t s at moisture l e v e l s normally too high f o r p r o c e s s i n g . UNT suspected the b i n d e r ' s b a s i c nature might help reduce the emission of a c i d gases. Sulfur dioxide i s reduced by burning dRDF simply because of dRDF s lower s u l f u r content (0.1-0.2% ) as compared t o western c o a l ' s (2.5-3.5%). A d d i t i o n a l r e d u c t i o n s can be r e a l i z e d through the w e l l known r e a c t i o n of s u l f u r oxide, a l e w i s a c i d , with the base f u n c t i o n of the calcium oxide's s u r f a c e i n i o n i c form. H y d r o l y s i s of the oxide i s known t o i n c r e a s e the r e a c t i o n k i n e t i c s . The r e a c t i o n r a t e i s b e l i e v e d t o be determined by the c o n c e n t r a t i o n of hydroxide s i t e s . The f o l l o w i n g equations d e p i c t t h i s process. (12). 2


1

H0

+ CaO

2

Ca(OH) + S0 2

> 2

>

Ca(OH)

2

CaS0 + 3

H0 2

In the combustion center the b i n d e r should be predominantly i n the oxide form. A f t e r t r a n s p o r t t o c o o l e r areas w i t h i n the system the previous l i s t e d equations become Appl.icable. The r e s u l t i s a r e d u c t i o n of S0 emissions. Furthermore, lower combustion temperatures obtained when c o f i r i n g dRDF tend t o favor the gas s o l i d r e a c t i o n of S0 with CaO. Lower combustion temperatures are a l s o known t o lead t o decreases i n n i t r o g e n oxide emissions. H y d r o c h l o r i c gas emissions w i l l tend t o i n c r e a s e due t o i n c r e a s e d c h l o r i n e c o n c e n t r a t i o n s from p l a s t i c s . The i n c r e a s e i n HC1 can be expected t o be minimal compared t o r e d u c t i o n i n SO /NO emissions. I t was f u r t h e r proposed t h a t the binder might p h y s i c a l l y reduce the p r o d u c t i o n of p o l y c h l o r i n a t e d biphenyls and d i o x i n s by adsorbing halogens p r i o r t o t h e i r formation or by absorbing the s p e c i e s d i r e c t l y as t y p i c a l l y demonstrated i n spray d r y e r absorber systems. (10,11) These hypotheses were t e s t e d a t a p i l o t p l a n t o p e r a t i o n a t Argonne N a t i o n a l Laboratory i n 1987. The s i x week program combusted over f i v e hundred tons of b i n d e r enhanced dRDF (bdRDF) blended with Kentucky c o a l a t heat contents of 10, 20, 30 and 50 percent. The Ca(0H) b i n d e r content ranged from 0 t o 8 percent by weight of dRDF. Emission samples were taken both before and a f t e r p o l l u t i o n c o n t r o l equipment (multicyclone and spray d r y e r absorber). A l l samples were taken t o UNT f o r a n a l y s i s . A d i s c u s s i o n of the s i g n i f i c a n t r e d u c t i o n s i n s u l f u r and n i t r o g e n oxides has been p r e v i o u s l y p u b l i s h e d (13) . X

2

x

x

2


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229

The f o l l o w i n g d i s c u s s i o n r e p o r t s r e s u l t s f o r a n a l y s i s of p o l y c h l o r i n a t e d biphenyls, polyaromatics, p o l y c h l o r i n a t e d d i o x i n s , and p o l y c h l o r i n a t e d furans. Experimental Isokinetic samples were taken f o r the analysis of p o l y c h l o r i n a t e d biphenyls (PCB's), polyaromatics (PAH's), p o l y c h l o r i n a t e d d i o x i n s (PCDD's) and p o l y c h l o r i n a t e d furans (PCDF's). The f o l l o w i n g sampling s i t e s were i n v e s t i g a t e d .


S i t e 1 combustion zone (2000°F) ; sample s i t e (1200°F) S i t e 2 p r i o r t o p o l l u t i o n c o n t r o l equipment (300°F) S i t e 3 a f t e r p o l l u t i o n c o n t r o l equipment (170°F) Sample c o l l e c t i o n was completed u s i n g an EPA modified Method 5 sampling t r a i n , and a XAD-2 r e s i n f o r t r a p p i n g the m a j o r i t y of organics. Various samples were spiked with i s o t o p i c a l l y l a b e l e d standards p r i o r t o soxhlet e x t r a c t i o n f o r 24 hours with benzene. The percent recovery of these standards provided a means t o determine e x t r a c t i o n e f f i c i e n c y and d e t e c t i o n l i m i t s . P o s s i b l e interférants were removed by sample e l u t i o n through a minimum of two a c i d and base modified s i l i c a g e l columns followed by an alumina column. Standard mixtures of native and i s o t o p i c a l l y l a b e l e d analytes were prepared f o r c a l c u l a t i o n of r e l a t i v e response f a c t o r s and c a l i b r a t i o n of the gas chromatography mass spectrometer (GC/MS). The GC/MS a n a l y s i s was performed with a Hewlett-Packard Model 5992B. (14) Results

and

Discussion 1

The EPA's s i x t e e n most hazardous PAH s (Table V) and a l l congener groups of PCB's were t e s t e d . The r e s u l t s are reported as t o t a l PCB and PAH concentrations found at a p a r t i c u l a r s i t e because i t i s f e l t t h a t the o v e r a l l production of PCB's/PAH's i s the parameter of primary concern. No s p e c i f i c compound was produced a t i n o r d i n a t e l y high l e v e l s . The r e s u l t s of s i t e 2 and s i t e 3 sampling areas are found i n Tables I and I I . Figures 1 and 2 c l e a r l y d e p i c t a reduction i n PAH and PCB emission as the binder concentration i s increased. Data are not a v a i l a b l e on a l l compositions due t o the mixing and sampling methods used. Tables I I I and IV show the calcium and c h l o r i d e contents of f l y ash from the m u l t i c y c l o n e f o r a s e r i e s of s p e c i f i c compositions. The calcium i s used as an i n d i c a t o r of the binder present i n the b o i l e r system during a p a r t i c u l a r sampling p e r i o d . The increase i n calcium o c c u r r i n g between the f i r s t c o a l "blank" run and the second blank o c c u r r i n g 3 weeks l a t e r , suggest a build-up of r e s i d u a l binder throughout the b o i l e r c o n f i g u r a t i o n . It i s noteworthy t h a t the increase i n water s o l u b l e c h l o r i d e


230


Table I Polyaromatic Hydrocarbons (PAH's); P o l y c h l o r i n a t e d Biphenyls (PCB's) a t S i t e 2

Site

mg PAH's cubic meter o f gas sampled

Coal

2

1.7

X

ΙΟ"

Coal/10%RDF/0%B

2

1.0

X

ΙΟ"

Coal/10%RDF/0%B * 2

7.6

X

ΙΟ"

Coal/10%RDF/4%B

2

1.6

X

ΙΟ"

Coal/10%RDF/8%B

2

4.0

X

ΙΟ"

Coal/10%RDF/8%B

2

8.1

X

ΙΟ"

Coal/20%RDF/0%B

2

3.5

X

Coal/20%RDF/0%B

2

4.6

X

ΙΟ"

Coal/20%RDF/4%B

2

2.2

X

10"

Coal/20%RDF/4%B

2

3.5

X

10"

Coal/20%RDF/8%B

2

2.4

X

10"

Coal/20%RDF/8%B

2

3.0

X

10"

Coal

1

3.4

X

10"

Coal

2

1.3

X

10'


Run#/Sample#

mg PCB's c u b i c meter o f gas sampled 3

2

6.2

X

10"

3

1.3

X

10"

2

2.7

X

ΙΟ"

2

1.4

X

10

3

7.6

X

10"

3

7.7

X

10"

9.7

X

ΙΟ"

2

7.7

X

ΙΟ"

1

2.0

X

ΙΟ"

1

2.9

X

ίο·

1

1.3

X

10"

1

3.4

X

ΙΟ"

1

5.4

X

ΙΟ"

1

3.9

X

ΙΟ"*

2

2

1

3

1(T 3

3

3


1

2

3

3

* T h i s sample was l i g h t e r i n c o l o r than a l l t h e r e s t Β = Binder

2

18. HILL ET AL.

231


Table I I Polyaromatic Hydrocarbons (PAH's); P o l y c h l o r i n a t e d Biphenyls (PCB's) a t S i t e 3


Run#/Samole#

Site

mg PAH's cubic meter o f gas sampled

mg PCB's c u b i c meter o f gas sampled

3

5.3

X

IO'

3

1.2

X

10'

Coal

3

4.6

X

ΙΟ"

Coal/10%RDF/0%B

3

6.3

X

ΙΟ"

Coal/10%RDF/0%B

3

1.5

X

io-

Coal/10%RDF/0%B

3

8.1

X

ΙΟ"

Coal/10%RDF/4%B

3

7.3

X

Coal/10%RDF/8%B

3

7.3

X

Coal/10%RDF/8%B

3

3.1

Coal/20%RDF/0%B

3

Coal/20%RDF/0%B

4

3

*

2

1.6

X

IO"

10"

3

9.1

X

10' n

IO"

3

1.1

X

IO"

X

IO"

3

3.1

X

io"

3.6

X

10"

4

2.8

X

IO"

4

3

4.0

X

IO"

3

1.2

X

IO"

3

Coal/20%RDF/4%B

2

7.9

X

IO"

2

4.2

X

IO"

2

Coal/20%RDF/4%B

3

4.9

X

IO"

2

6.5

X

IO"

3

Coal/20%RDF/8%B

3

1.0

X

IO"

3

2.4

X

IO"

Coal/20%RDF/8%B

3

8.1

X

IO"

3

8.5

X

IO"

Coal

3

7.0

X

IO"

2

4.0

X

IO'

Coal

3

1.4

X

IO"

3

4.3

X

IO"

*

3

3


4

3

5

I n t e r f e r e n c e made i t impossible t o determine the q u a n t i t y o f PCB's i n t h i s run

Β = Binder

3

4

3

4

232


Table I I I Calcium L e v e l s i n F l y Ash

ppm o f Calcium


Fuel

3,000 6,700 10,600 15,000 4,200

F i r s t c o a l blank Coal - 10% dRDF (0% binder) Coal - 10% dRDF (4% binder) Coal - 10% dRDF (8% binder) Second c o a l blank

Table IV Soluable C h l o r i d e L e v e l s i n F l y Ash

ppm o f C h l o r i d e

Fuel F i r s t c o a l blank Coal - 10% dRDF (0% binder) Coal - 10% dRDF (4% binder) Coal - 10% dRDF (8% binder) Second c o a l blank

100 190 280 320 280

Table V EPA P r i o r i t y PAH"s

Naphthalene Acenapthylene Acenapthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene

Benzo-a-anthracene Chrysene Benzo-b-fluoranthene Benzo-k-fluoranthene Benzo-a-pyrene Dibenzo-a,h-anthracene Benzo-g,h,i-perylene Idendo-1,2,3,-g,d-pyrene


18. HILL ET AL.


0.12 0.1


Ή -g S .y

0.08 o.o6

i 0.02 0

30

30 (less plastic)

Percent dRDF IH

0 % binder

β3

4 % binder

E l l 8 % binder

F i g u r e 1.

PAH Concentrations

Detected

F i g u r e 2.

PCB Concentrations

Detected


233


234


i n the f l y ash f o r the 10% RDF samples i s on the same order as t h e r e d u c t i o n o f PCB's seen i n F i g u r e 2. This i s presumably due t o the lime's a b i l i t y t o b i n d t h e c h l o r i d e i n t h e combustion area. The much higher c h l o r i d e content of t h e second c o a l blank ash r e l a t i v e t o t h e f i r s t blank can be explained by assuming a longer c o n t a c t time f o r c h l o r i d e a d s o r p t i o n on t h e r e s i d u a l binder as t h e b i n d e r became s a t u r a t e d throughout the b o i l e r system. (15) The d i o x i n and furan a n a l y s i s i n i t i a l l y concentrated on t h e t e t r a c h l o r i n a t e d s p e c i e s present a f t e r t h e p o l l u t i o n c o n t r o l equipment a t sample s i t e 3. Priority was g i v e n t o d e t e c t i n g the 2,3,7,8 congeners because o f t h e i r higher t o x i c i t y . Sample s i t e 3 was chosen because of t h e importance o f determining what c o n c e n t r a t i o n s o f the a n a l y t e , i f any, were reaching the environment. Table VI shows t h a t no d i o x i n s o r furans were found a t the l i s t e d detection l i m i t s . In order t o d i s c o v e r i f the a n a l y t e was simply d e p o s i t i n g on f l y ash, samples o f composited f l y ash were a l s o analyzed f o r adsorbed PCDD's and PCDF's. The f i v e f l y ash samples chosen t o represent the f u l l spectrum o f t e s t burn compositions are l i s t e d i n Table V I I . Analysis r e s u l t s repesented by Tables V I I I through XII again demonstrate no d e t e c t a b l e t r a c e o f d i o x i n s o r furans. A d d i t i o n a l analyses were subsequently performed f o r penta, hexa, hepta, and octa congeners a t sample s i t e 3. In a l l cases, no d i o x i n s o r furans were detected. These somewhat s u r p r i s i n g negative r e s u l t s l e d t o a search f o r a means t o improve d e t e c t i o n l i m i t s . Lower d e t e c t i o n l i m i t s were thought t o be o b t a i n a b l e through t h e use o f a high r e s o l u t i o n mass spectrometer (HRMS) . T r i a n g l e L a b o r a t o r i e s a t Research T r i a n g l e Park, NC, was c o n t r a c t e d f o r use o f t h e i r equipment and e x p e r t i s e i n t h i s area. E i g h t r e p r e s e n t a t i v e samples were chosen f o r HRMS a n a l y s i s . Three o f the p r e v i o u s l y analyzed samples from s i t e 3 were chosen as v e r i f i c a t i o n on the accuracy o f UNT's r e s u l t s . The remaining samples were o f v a r i o u s burn compositions from s i t e 2 p r i o r t o p o l l u t i o n c o n t r o l equipment. These samples were s e l e c t e d because UNT's r e s u l t s suggested t h a t no PCDD's o r PCDF's were present a f t e r p o l l u t i o n c o n t r o l . T r i a n g l e L a b o r a t o r i e s g e n e r a l l y improved r e s u l t s only on the order o f one magnitude, and confirmed UNT's f i n d i n g s with negative r e s u l t s f o r d i o x i n s and furans a t s i t e 3. Only one o f the s i t e 2 samples had any d e t e c t a b l e analyte. Emissions o f 0.41 ng/m t o t a l HxCDD and 0.66 ng/m t o t a l OCDD were found f o r the sample from a 20% dRDF/ 0% b i n d e r / c o a l burn mixture. I t should be noted t h a t t h e t o x i c i t y e q u i v a l e n t f a c t o r (TEF) f o r HxCDD i s 0.0004 l e a d i n g t o a emission r a t e o f 0.16 pg/m while t h e TEF f o r OCDD i s 0. Emission r a t e s f o r both a r e c e r t a i n l y much lower than any c u r r e n t standards. R e s u l t s o f the same sample a t s i t e 3 found no t r a c e o f d i o x i n o r furan. 3


18. HILL ET AL»

235


Table VI T e t r a - C h l o r i n a t e d Dioxins and T e t r a - C h l o r i n a t e d Furans at S i t e 3


Run#/Sample# Coal

Site 3

TetraChlorinated Dioxin Level BDL

TetraDetection Chlorinated Limit Furan Level nq/m 0.72 BDL 3

Coal/10%RDF/0%B

3

BDL

BDL

1.99

Coal/10%RDF/0%B

3

BDL

BDL

4.07

Coal/10%RDF/0%B

3

BDL

BDL

5.24

Coal/10%RDF/4%B

3

BDL

BDL

4.80

Coal/10%RDF/8%B

3

BDL

BDL

4.27

Coal/10%RDF/8%B

3

BDL

BDL

4.27

Coal/20%RDF/0%B

3

BDL

BDL

0.49

Coal/20%RDF/0%B

3

BDL

BDL

0.47

Coal/20%RDF/4%B

3

BDL

BDL

4.16

Coal/20%RDF/4%B

3

BDL

BDL

4.10

Coal/20%RDF/8%B

3

BDL

BDL

4.78

Coal/20%RDF/8%B

3

BDL

BDL

4.78

Coal

3

BDL

BDL

3.85

Coal

3

BDL

BDL

4.85

3

ng/m BDL

= =

nanograms per cubic meter Below Detection

Limits

Β = Binder



236

Table VII Analyzed F l y Ashes Compositions

Composite Sample #


Date

Composition

June 21-22, 1987

20% Btu Content Reuter RDF and 70% Btu Content Coal - 0% Binder

J u l y 7, 1987

30% Btu Content Reuter RDF and 70% Btu Content Coal - 0% Binder (no plastic)

June 15-16, 1987

Coal Only

June 23-24, 1987


J u l y 4-5, 1987


Table V I I I GC/MS A n a l y s i s o f Ash Sample 5 f o r P o l y c h l o r i n a t e d Dioxins and Furans

Mass 304/306 320/322 340/342 356/358 374/376 390/392 408/410 424/426 442/444 458/460

=

BDL BDL BDL BDL BDL BDL BDL BDL BDL BDL

TCDF TCDD PeCDF PeCDD HxCDF HxCDD HpCDF HpCDD OCDF OCDD

% Extraction Efficiency BDL

Amount Found ησ/σ sample)

Analytes

=

Detection Limit (ηα/α sample) 0.9966 0.9966 2.4916 2.4916 2.4916 2.4916 2.4916 2.4916 4.9832 2.4916

57.9

Below D e t e c t i o n L i m i t


18. HILL ET AL.


237

Table IX GC/MS A n a l y s i s o f Ash Sample 4 f o r P o l y c h l o r i n a t e d Dioxins and Furans


Mass 304/306 320/322 340/342 356/358 374/376 390/392 408/410 424/426 442/444 458/460



Amount Found (na/a sample)

Analytes

=


=

Detection Limit (ng/g sample) 1.0001 1.0001 2.5002 2.5002 2.5002 2.5002 2.5002 2.5002 5.0005 2.5002

9.2

Below Detection L i m i t Table X

GC/MS A n a l y s i s o f Ash Sample 3 f o r P o l y c h l o r i n a t e d Dioxins and Furans

Mass

Analytes

304/306 320/322 340/342 356/358 374/376 390/392 408/410 424/426 442/444 458/460



=

Amount Found Detection Limit (ησ/σ sample) (ησ/σ sample) BDL BDL BDL BDL BDL BDL BDL BDL BDL BDL

1.0022 1.0022 2.5055 2.5055 2.5055 2.5055 2.5055 2.5055 5.0111 2.5055

= 53.1

Below Detection L i m i t



238

Table XI GC/MS A n a l y s i s o f Ash Sample 2 f o r P o l y c h l o r i n a t e d Dioxins and Furans


Mass

Analytes

304/306 320/322 340/342 356/358 374/376 390/392 408/410 424/426 442/444 458/460



=

Amount Found D e t e c t i o n L i m i t (ησ/g sample) (ηα/g sample) BDL BDL BDL BDL BDL BDL BDL BDL BDL BDL

0.9965 0.9965 2.4913 2.4913 2.4913 2.4913 2.4913 2.4913 4.9825 2.4913

= 81.2

Below Detection L i m i t

Table X I I GC/MS A n a l y s i s o f Ash Sample 1 f o r P o l y c h l o r i n a t e d Dioxins and Furans

Mass

Analvtes

304/306 320/322 340/342 356/358 374/376 390/392 408/410 424/426 442/444 458/460

-




Amount Found Detection Limit (na/a sample) (na/a sample) 0.9992 0.9992 2.4980 2.4980 2.4980 2.4980 2.4980 2.4980 4.9825 2.4980

= 133.6

Below D e t e c t i o n L i m i t Khan; Clean Energy from Waste and Coal ACS Symposium Series; American Chemical Society: Washington, DC, 1992.


18. HILL ET AL.


239

Thus the p o l l u t i o n c o n t r o l equipment i s apparently efficient in removing the analyte at these low c o n c e n t r a t i o n s . (16) There i s a n a t u r a l d i s i n c l i n a t i o n t o r e p o r t r e s u l t s such as found i n Table VI and Tables V I I I through XII. No concrete values f o r d i o x i n and furan c o n c e n t r a t i o n produced d u r i n g the combustion of the RDF are presented. Instead, one f i n d s d e t e c t i o n l i m i t s f o r which PCDD and PCDF l e v e l s were found t o be below. When attempting t o i n v e s t i g a t e the environmental impact of a developing i n d u s t r y , i t i s important to c o n t r i b u t e a l l t e c h n i c a l l y r e s p o n s i b l e information f o r the development of a r e l i a b l e database. T h i s becomes p a r t i c u l a r l y imperative when d e a l i n g with s e n s i t i v e t o p i c s , such as the production of d i o x i n s and furans during the combustion of r e f u s e d e r i v e d f u e l . The presented data provides b a s e l i n e values as a means f o r p r e d i c i t i n g p o t e n t i a l p o l l u t i o n l e v e l s f o r f u t u r e i n d u s t r i a l demonstrations and f o r the development of adequate d e t e c t i o n techniques. Conclusion R e s u l t s of the p i l o t p l a n t program i n d i c a t e s t h a t the binder enhanced d e n s i f i e d r e f u s e d e r i v e d f u e l can be c o f i r e d with c o a l , at the l e v e l s t e s t e d , without producing d e t e c t a b l e amounts of d i o x i n s or furans. PCB's and PAH s are aypparently reduced as a f u n c t i o n of the quicklime binder content. 1

Literature

Cited

1. Ohlsson, O., et. a l . , Proceedings of the American Association of Energy Engineers, 1986, p. 1. 2. Gershman, H.W., Brickner, R.H., Brutton, J . J . , Small-Scale Municipal S o l i d Waste Energy Recovery Systems; VNR, NY, 1986. 3. Smith, F.A., Waste Age, A p r i l 1976, p. 102. 4. Rice, F., Fortune, 1988, 117, pp. 96-100. 5. O f f i c e of Technology Assessment, OTA Report No. 052003-01168-9, 1989. 6. Vogel, S., Discover, 1988, 42, No. 4, p. 76. 7. Rathje, W.L., The A t l a n t i c Monthly, December 1989, 264, pp. 99-109. 8. Johnson, P., McGill, K.T., USA Today, August 26, 1988. 9. Carpenter, Β., Windows, 1988, p. 9. 10. Daugherty, K.E., et. a l . , Proceedings of the American Association of Energy Engineers, 1986, p. 930935. 11. Daugherty, K.E., et. a l . , Phase 1, F i n a l Report, U.S. Department of Energy, ANL/CNSV-TM-194, 1986.



240


12. Mobley, J.D., Lim, J.K., In Handbook of P o l l u t i o n Technology, Calvert, S., Englund, H.M.; John Wiley & Sons, N.Y., 1984 pp. 210-211. 13. Jen, J.F., Ph.D. Dissertation, Analysis of Acid Gas Emissions i n the Combustion of the Binder Enhanced Densified Refuse Derived Fuel by Ion-Chromatography, University of North Texas, TX, 1988. 14. Poslusny, Μ., Moore, P., Daugherty, Κ., Ohlsson, O., Venables, Β., American I n s t i t u t e of Chemical Engineers Symposium Series, 1988, 84, No. 265, pp. 94-106. 15. Poslusny, M. Ph.D. Dissertation, Analysis of PAH and PCB Emissions From the Combustion of dRDF and the Nondestructive Analysis of Stamp Adhesives, University of North Texas, TX, 1989. 16. Moore, P. Ph.D. Dissertation, The Analysis of PCDD and PCDF Emissions From the C o f i r i n g of Densified Refuse Derived Fuel and Coal, University of North Texas, TX, 1990. RECEIVED April 6, 1992


Clean Energy from Waste and Coal - ACS Publications - American

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