Znd. Eng. Chem. Res. 1993, 32, 173-177
173
GENERAL RESEARCH Coal Deashing by Alkali Fusion Makoto Yamaye, Kohji Yoshinaga,t Kenji Matsumoto,t and Taketoshi Kito*st Faculty of Engineering, Kyushu Kyoritsu University, Jiyugaoka, Yahatanishi-ku, Kitakyushu-shi 807, Japan
Deashing of Akabira coal was studied by NaOH or KOH fusion, followed by successive washing with water and hot water. Ash removal reached approximately 45% at 260 "C and 80% at 380 "C.Among major ash components, FezOs was least susceptible to removal, while SiOz was removed by 55% even at 260 "C. Pyridine extract yield reached maximum (56%) a t 300 "C and decreased a t either higher or lower temperatures than 300 " p
Introduction Coal is a chemically complex mixture composed of both combustible and incombustible substances. Usually even coals grouped into the same name may give somewhat different analytical data from place to place. Coal ash is generally defined as a mixture of mineral matters incombustible at 800 "C in air and contains various inorganic metal oxides and salts. The ash may be different in chemical composition from one originally contained in raw coal. The term "deashing" used here means removal of incombustible mineral matters from raw coal. The ash causes some problems for combustion of coal and on disposal after combustion of coal. One of the main problems in coal liquefaction may be from deashing coal. In some instances, however, it is generally thought that the ash acta as a hydrogenation catalyst in coal liquefaction (Probstein and Hicks, 1982), but the ash is not necessary in combustion. There have been many reports on the treatment of coal with alkali. For example, Kasehagen (1937) reported the action of aqueous alkali on a bituminous coal at 250-400 "C,but there was no discussion on ash removal from coal. We previously reported that coal was fused with sodium hydroxide to produce benzene-, methanol-, and pyridinesoluble products in good yields. An effective ash removal was accomplished by the procedure in which, after coal fusion at temperatures between 320 and 370 "C, the reaction mixture was simply washed with water (Asahara et al., 1983). Srivaatava et al. (1988) fused a coal with sodium hydroxide at 400-700 "C, higher temperatures than ours, and calculated the weight of NaOH theoretically required for the fusion of ash components, but they did not refer to the poesibility of coal deashing. Wang et al. (1986) treated coal with aqueous NaOH at lower temperatures (127-187 "C) and found that an excellent recovery (above 92%) was accomplished with this method. This treatment at 187 "C was effective in removing most of the minerals contained in the coal (81-89%). However, we suspect that, by this treatment, coal may not be decomposed into products readily soluble in organic solvents, because the temperature was too low to decompose coal. Balcioglu and Yilmaz (1990) treated lignite with molten alkali at 290 to 375 "C. 'Present address: Department of Chemistry, Kyushu Institute of Technology, Tobata-ku, Kitakyushu-shi 804,Japan.
They reported a decrease of ash content from 14.0 w t % (untreated coal) to 1.85 wt % (the lowest value, at 375 "C for 0.5 h), together with an increase in the yield of pyridine extract (95% ). We reinvestigated the alkali fusion of coal with emphasis on coal deashing. For effective stirring to be assured in rather small scale runs, the fusion was conducted with a large excess of alkali.
Experimental Section Instrumental Analysis. The contents of metals were determined by flame atomic absorption spectrophotometer (Hitachi Z-6100),Zeeman atomic absorption spectrophotometer (Hitachi 170-70),and ICP emission spectrometer (Shimadzu ICPS-500). Measurements by these instruments were carried out according to JIS K 0120 (1982). Coal. Akabira coal produced in Hokkaido, Japan, was powdered to about 80 mesh, dried at 110 "C for 2 h in vacuo (75 mmHg), and stored under nitrogen atmosphere. For comparative study, a waste coal from Chikuho in Kyushu, Japan, was also used after similar pretreatment. Their analytical data are included in Table I. Inorganic Reagents. Guaranteed grades of sodium hydroxide, potassium hydroxide, and hydrochloric acid (Kanto Chemical Co., Inc.) were used. Alkali Fusion of Coal and Posttreatment. A typical example is described. Into a nickel-coated stainless-steel autoclave were placed Akabira or waste coal (5.0 g) and sodium hydroxide (20.0 g). The mixture was heated to 300 "C (it took approximately 1 h) in a nitrogen stream and was kept at this temperature for 1 h with mechanical stirring. After cooling, the mixture was neutralized with aqueous HC1 (about 1 N) and filtered by suction. The residue was washed with water to remove a water-soluble part and was then extracted with hot water (about 88 "C) in a Soxhlet extractor. The extract was combined with the water-soluble part. The combined solution was adjusted to pH 7 and diluted to 1L with water. The water-insoluble part was dried in a vacuum oven (75 mmHg) at 80 "C for 2 h. Determination of Ash. Approximately 2 g of sample coal (treated or untreated) was heated at 800 "C for 8 h in the presence of air. The ash content was calculated from eq 1. ash content ( w t %) = (weight of combustion residue/ weight of sample coal) X 100 (1)
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174 Ind. Eng. Chem. Res., Vol. 32, No. 1,1993 Table I. Analyses of Untreated Coals elementary" ( % ) coal( C H N Akabira' 78.01 5.59 1.85 W88tee 64.03 4.47 0.75 Miikg Iizukag Horonaig
SiOz 50.5 59.0
A1203 23.9 22.2
Fez03 7.1 2.9
49.2 58.8 58.6
7.2
25.8 19.6
15.3 6.5 7.1
ashb (wt % ) MgO CaO 3.6 5.3 0.6 1.0 2.0 0.2 1.6
10.1 3.5 7.7
Na20 1.4
KzO 0.6
NazO + K 2 0 7.9
othersd 7.6 14.3'
3.0
8.3 2.2
2.4
3.0
"Analyses of C, H, N, and 0 were made on an ash-free basis. bRatios (wt 5%) in ash were calculated as the oxides shown in the table. 'Miike and Iizuka coals were produced in Kyushu, Akabira and Horonai coals, in Hokkaido. Others = ash weight - total weight of (SO2 + AlZO3+ Fez03 MgO + CaO + NazO + KzO) or of @ioz + A1203 + Fe203+ MgO + CaO). eAshes were analyzed by ICP emission spectrometry. Ash contents of untreated Akabira and waste coals were 3.79 and 79.5%, respectively. 'Contained 1.0% TiOz. BIki and Masumori (im).
+
Determination of Mineral Matters (Na, K, Fe, Al, Ca, Mg, and Si). The determination was made in conformity to JIS M 8815 (1976)with some modifications. Na. In a platinum crucible were placed a dried sample (0.5g), hydrofluoric acid (a%, 3 mL), and a few drops of sulfuric acid. The mixture was heated to dryness at 250 "C to remove silica (as SiF4).This procedure was repeated three times. The resulting residue was dissolved in concentrated nitric acid (9 mL). After addition of perchloric acid (70%, 6 mL), the solution was heated gently in the crucible with a burner for 3 h and then strongly until white gas evolution had ceased. The residue was cooled to room temperature, and, after addition of water (500 mL), filtration was performed (filtrate A). The water-insoluble part was washed with hot dilute nitric acid (filtrate B)until the filtrate was no longer tinged with red by addition of aqueous ammonium thiocyanate. Na metal contained in the combined filtrates (A and B) was analyzed at the wavelength of 589.0 nm by flame atomic absorption spectrophotometry. The water-insoluble part together with the filter paper was incinerated in a platinum crucible. The residue was dissolved in concentrated HCl(5 mL) and diluted with hot water (30mL). Na metal contained in the resulting solution was similarly analyzed by flame atomic absorption spectrophotometry. K. A dried sample (0.5 g) was treated by the same procedure as described for Na. Then K metal was analyzed at 766.5 nm by flame atomic absorption spectrophotometry. Fe, Al, Ca, Mg, and Si. A dried sample (0.025g) was mixed with mixed carbonates (Na2C03:K2C03= 1:l molar ratio, 1.0g) in a platinum crucible. Then the mixture was covered with the mixed carbonates (0.2 g), fused by gradual heating in an electric oven to 900 "C, and kept at 900 "C for 0.5 h. After cooling to room temperature, the residue was transferred to a conical beaker (300mL), completely dissolved in concentrated HC1 (10 mL), and heated at 70-80 "C to evaporate water and then at 110 "C to dryness. The dried residue was finely powdered. To this were added concentrated HCl(l5-20 mL) and then water (100 mL). The resulting mixture was heated in a water bath to completely dissolve the water-soluble part. The final solution, which contained compounds of Fe, Al, Ca, Mg, and Si (a trace amount) metals, was diluted to 250 mL with water after the insoluble product (product A) containing Si compound was removed by filtration using No. 5 filter paper. Fe metal was analyzed at 248.3 nm by Zeeman atomic absorption spectrophotometry. Ca and Mg metals were analyze$ at 422.7 nm (for Ca) and 285.2nm (for Mg) by Zeeman atomic absorption spectrophotometry. For reference, Ca, Al, and Mg were also analyzed at 393.366, 396.153,and 285.213 nm, respectively, by ICP emission spectrometry.
For Si determination, water was evaporated off from the final solution obtained above to dryness at 70-80 "C, and the residue was dried at 110 "C for 1 h, followed by the similar procedures mentioned above to get the water-insoluble product (product B), which contained a trace amount of Si compound. The combined products A and B were incinerated in a platinum crucible at lo00 "C for 1 h. To the residue was added hydrofluoric acid (48%, 5-10 mL) together with a few drops of sulfuric acid. Then the mixture was incinerated at 1000 "C for 0.5 h. The resulting weight loss corresponds to the amount of Si. Aluminum was determined as aluminum oxide. In this procedure, aluminum hydroxide was precipitated from the final solution and then converted to aluminum oxide by incineration at lo00 "C for 1 h. Theoretical Weight of NaOH Required for Alkali Fusion. Calculation was made based on the method reported by Srivastava et al. (1988), in which, with exclusion of CaO, MgO, Na20,and K20 from the calculations, 1 mol of either Si02,Al2O3, or Fe203was assumed to react with 2 mol of NaOH.
Results and Discussion The analytical data for ashes obtained from five coals are summarized in Table I. Three major elements were Si, Al, and Fe. We conducted experimental works mainly using Akabira coal, unless otherwise stated. Behavior of Ash in Coal. Akabira coal was fused with sodium hydroxide at temperatures in the range of 260-400 "C for 1 h, and the reaction mixture was neutralized with aqueous hydrochloric acid as quickly as possibile after being cooled, washed with water, and then extracted with hot water in a Soxhlet extractor, giving three parts, namely, the water-soluble, hot water-soluble, and residual parta. The ash content in the residue was calculated according to eq 1 and is shown in Figure 1 (line b). The ash content (weight percent) is defined here as the weight percent of the residue that remained after incineration of the sample at 800 "C in air. As shown in the figure, simple washing of the residue with water and then with hot water effected a considerable decrease in ash content. Ash removal calculated according to eq 2 is shown in Figure 1 (line c). Ash removal gradually increased with an increase in temperature (260-400 "C). ash removal (wt %) = 100 - (weight of the ash in the water-insoluble part/ weight of the ash in raw coal) X 100 (2) In the alkali fusion of coal, sodium hydroxide would react with ashes and organic materials to form various types of sodium compounds. Though these compounds were mostly extracted with hot water during the posttreatment, some remained in the residual part. The amount of sodium incorporated into the water-insoluble
Ind. Eng. Chem. Res., Vol. 32, No. 1, 1993 178 Table 11. Sodium Content in Ash from Akabira Coal treating temperature ("C) 260 280 water-insoluble productn (9) 94.0 91.3 1.07 0.23 Nabsc(mg)
300 90.2 207
Calculation was made based on 100 g of untreated coal. contained 38.9 mg of Na.
320 87.2 183
340 81.5 179
360 74.9 240
380 74.4 275
Na (mg) contained in the water-insoluble part.
400 72.4 427
Untreated Akabira coal
Table 111. Pyridine Extract Yield (9'0)at Various Temmratures ( O C ) coal Akabira coal waste coal
treating method NaOH fusion NaOH fusion heated in aqueous NaOHb KOH fusion heated in aqueous KOHb
UT" 17 10
26OOC 15
28OOC
12
pyridine extract yield 300OC 320 OC 34OOC 56 28 20 46 23 19 17 9 15 17 27
36OOC 11 17 10 5 10
390 OC 13 7 4 5
Pyridine extract yield of untreated Akabira or waste coals. Waste coal (5 g) was heated in 100 mL of aqueous NaOH (20%) or KOH (20%) for 1 h. 1 0 0
4.
8 0
0 n
al ' 6 0
0
3. 03
-
L
06 0 M
I
m
(D
>
3
-x
2 . 0-
0 4 0 E 0
2 6 0
300
340
T e m p e r a t u r e
3 8 0 ("c)
Figure 2. Organic material recovered after deashing.
v
a I. 0
2 0
0 2 6 0
280
300
3 2 0
3 4 0
T e m p e r a t u r e
3 6 0 ("c)
3 8 0
4 0 0
Figure 1. Ash removal and ash content: line a, ash content (corrected); line b, ash content (uncorrected); line c, ash removal (uncorrected); line d, ash removal (corrected).
part by this treatment was subtracted from values on line b, and the calibrated line is shown in Figure 1 (line a). However, we would like to use uncorrected values as the ash content. Although untreated coal originally contains sodium (1.38 wt % as sodium oxide), we could not distinguish the sodium in raw coal from the one formed during the fusion. Accordingly, these calculations were made on the assumption that the sodium contained in raw coal was removed completely as its water-soluble oxides or salts in this treatment. The amount of sodium incorporated into the residual part was noticeable above 300 "C (Table 11). Coal Recovery. During deashing treatment, coal was partially decomposed into water-soluble products (therefore, the denominator in eq 1 varies depending on the reaction conditions). Coal recovery (weight percent) calculated according to eq 3 was plotted against the treating temperature in Figure 2. coal recovery (wt %) = (weight of the residual part/weight of raw coal) X 100 (3) According to our previous paper, coal is decomposed into organic solvent-soluble products (Asahara et al., 1983). Some of these may partially change into water-soluble or volatile products. However, recovery of the latter products was not attempted. Alkali fusion of coal at higher temperatures proved to be effective for coal deashing (Figure 11, while a considerable amount of the organic product was lost (Figure 2). For example, when 100 g of coal (con-
Table IV. Analyses of Four Metals in Ash from Water-Insoluble Part content ( % ) as metal oxidea** treating temp ("C) CaO Ma0 Na,O K,O untreated 5.32 3.58 1.38 0.61 0.15 260 0.31 0.10 280 Symbol --" means that these metals could not be detected by Zeeman atomic absorption spectrophotometry or flame atomic absorption spectrophotometry. Calculation was based on the assumption that each metal in the ash is present as ita oxide shown in the table.
taining 3.79 g of ash) was fused with 400 g of NaOH at 400 "C, 24.6 g of an organic material could not be recovered, though the ash content decreased from 3.79 to 1.08%. If an effective recovery of the resulting organic product is assured, coal fusion at higher temperatures would be advantageous. However, as previously reported (Asahara et al., 1983),the total yield of the solvent extract will decrease at higher temperatures. The pyridine extract yield by coal fusion in Table I11 also indicates this tendency. The treatments at temperatures below or above 300 "C gave poor yields, though the maximum yield and optimum temperature generally depended on the kind of coal and reaction conditions, as we reported before (Asahara et al., 1983). Removal of Metal Oxides from Coal. Coal contains metal oxides and salts of such elements as Si, Fe, Al, Ca, Mg, Na, K, etc. Of these elements, the former three are major components. In this report, Si, Fe, Al, Ca, Mg, Na, and K were analyzed. We assume that these elements are present in forms of such oxides as silica @io2),alumina (A1203), iron(II1) oxide (Fe203),calcium oxide (CaO), magnesium oxide (MgO), sodium oxide (Na20),and potassium oxide (K20). These elements, of course, may actually exist as many other types of oxides and salts in coals. Coal was fused with sodium hydroxide a t 260 and 280 OC for 1 h and washed with hot water in a Soxhlet ex-
176 Ind. Eng. Chem. Res., Vol. 32, No. 1, 1993 Table V. Distribution of Metal Oxides (wt fusing temp time metal oxide ("C) (h) 280 1 SiO, 300 300 340 Fe203
280 300 300 340
1
3 1 1 1
3 1
water-soluble Part
hot water-soluble Part
insoluble Part
oxideb reduction
39.9 51.4 59.1 68.9
0 11.9 1.7 0.3
60.1 36.7 39.2 30.8
39.2 63.3 60.8 69.2
8.0 10.0 5.9 16.7
0.1 2.8 0.4 0.1
91.9 87.2 93.7 83.2
8.0 12.8 6.2 16.8
0.1 3.2 3.5 0.1
53.3 51.9 64.4 17.9
46.7 48.1 35.6 82.1
280 300 300 340
3 1
46.6 44.9 32.1 82.0
CaO
300 300 340
1 3 1
7.8 8.6 23.3
10.0 3.6 1.4
82.2 87.8 75.3
MgO
300 300 340
1 3 1
7.3 2.0 8.8
2.7 1.3 0.9
90.0 96.7 90.3
TiOz
300 300 340
1 3 1
4.3 7.3 11.4
1.7 0 0
94.0 92.7 88.6
1 1
Distribution of metal oxides (wt 70)in untreated waste coal: SiO,, 59.0; Fez03,2.91; A1203,22.2; CaO, 1.0; MgO, 0.6; TiOz, 1.0; others, ( W )= 100 - [total weight of metal oxide (g) contained in (water-soluble part + hot water-soluble part + insoluble part)] x 100/metal oxide content ( 9 ) in untreated waste coal. 13.3 (total 100). bOxide reduction
tractor. Ca, Mg, Na, and K in the ash from the coal were analyzed by Zeeman atomic absorption spectrophotometry or flame atomic absorption spectrophotometry. The results are summarized in Table IV. As shown in the table, a considerable decrease in the amount of these elements was observed even at 260 "C, and at 300 "C almost none of them shown in the table could be detected. Therefore, we did not perform the analysis of these elements in the following experiment. The amounts of silica (SiOJ, aluand iron(II1) oxide (Fez03)contained in the mina (Alz03), ash from the residual part were determined, and the ash reduction calculated from eq 4 was plotted versus temperature in Figure 3. As depicted in the figure, a sigoxide reduction ( w t % ) = 100 (weight of the oxide in ash from the residual part/ weight of the oxide in ash from raw coal) X 100 (4) nificant removal (55%) of silica even at 260 "C contrasted with a low reduction of alumina and iron(II1) oxide over the lower temperature range. Removal of alumina was slow below 320 "C, while above that temperature it became markedly accelerated. Iron(II1) oxide was the metal oxide least susceptible to removal. This oxide required higher treating temperatures (360 "C) than alumina for an effective reduction. According to Ohtsuka's method which treated coal with aqueous NaOH at lower temperatures (127-187 "C), mineral matters such as Si, Al, and Fe were able to be removed by 68-85, 87-96, and 26-87 % , respectively, depending on the kind of coal (Ohtsuka et al., 1987. Related literature: Wang et al., 1986). The amounts of the oxides removed are smaller by our method than by theirs. According to the method reported by Srivastava et al. (1988), where each of SiOz, Al2O3,and Fe,O, is assumed to react with 2 mol of NaOH and CaO, MgO, NazO, and KzO are excluded in the calculation. Thus, the theoretical weight of NaOH required for our reaction was estimated to be 3.44 g (that is, 1.98 g of Na) per 100 g of raw coal. This fact suggests that a sufficient amount of NaOH was used in our experiments. Therefore, a reason for our lower reductions may be explained as follows. Though the melting point of pure NaOH is 328 "C, we
loor 8 0
-
I
;R
/
' 6 0 -
> 04 0 E
4
DI
a: 2 0
0
2 6 0
2 8 0
3 0 0 3 2 0 T ernp e r a
3 4 0 t
u r e
3 6 0
3 8 0
4 0 0
(C)
Figure 3. Removal of metal oxides (SiO,, A1203,and Fe,O,).
suppose NaOH melts, in practice, below 328 "C. However, the lower removal of silica below 300 "C indicates that NaOH may not be fused below 300 "C. Coal Fusion with Potassium Hydroxide. Akabira coal was fused at 360 "C with potassium hydroxide by a method similar to the reaction with sodium hydroxide, and two parts, water-soluble and -insuluble parts, were obtained. The results were as follows: coal recovery = (weight of the residual part/ weight of raw coal)X 100 = 80.1% ash content in the recovered coal = (weight of ash contained in the residual part/ weight of the residual part) X 100 = 3.29% K 2 0 content in ash = (weight of K 2 0 in ash from the residual part/ weight of ash from the residual part) X 100 = 48.9% ash reduction = (weight of ash from water-insoluble part/weight of ash from raw coal) X 100 = 30.4% The corresponding values obtained from the reaction with
Ind. Eng. Chem. Rea., Vol. 32, No. 1, 1993 177 sodium hydroxide at 360 "C were 74.9, 1.74, 24.9, and 65.790, respectively. In the former reaction, a greater amount of potassium (48.9%) remained in the ash with a lower ash removal (30.4%). Although a higher recovery was accomplished from the former reaction, the difference between the calibrated recoveries calculated by subtraction of the ash weight both from the numerator and denominator (76.4 and 80.6%, respectively) was only 4.2%. Therefore, we do not consider that there is any appreciable advantage for using potassium hydroxide in place of sodium hydroxide. Alkali Treatment of Waste Coal. For clarification of the behavior of coal ash by alkali fusion, waste coal, which contains 79.5% incombustible matter, was treated with either NaOH (neat), aqueous NaOH (20%), KOH (neat), or aqueous KOH (20%). The resulting mixture was extracted with pyridine. The pyridine extract yields are listed in Table 111. The fusion with NaOH (neat) gave a better result than the other treatments. The waste coal was fused with NaOH to give a product, which was separated into water-soluble, hot water-soluble, and residual parta. Each part was analyzed in terms of mineral matters by ICP emission spectrometry. The results are summarized in Table V. Almost all of the oxides were able to be removed by washing the fusion mixture with water. Generally speaking, a longer reaction time led to a satisfactory oxide removal with some exceptions. On the other hand, higher fusing temperatures will give better resulta at the sacrifice of the solvent-extract yield. This indicates that the optimum conditions for coal deashing are also favorable for maximization of the solvent-extract yield. In addition, SiOz and A1203(and Fez03 in some coal) are the major mineral componenta in many coals. These were effectively removed at temperatures between 300 and 340 "C.
Conclusion Alkali fusion of coal was proved to be an effective method for removing mineral matters contained in coal. An
optimum temperature to accomplish deashing of 80% was estimated to be 380 "C, with recovered organic material of 75%. Of three major mineral matters in Akabira coal, both silica and alumina were removed by 90% at 400 "C.Silica, the most abundant component (50.5%), was most readily removed even at lower temperatures (for example, 64% a t 300 "C). Alumina, the second major component (23.9%), however, was resistant to removal at temperatures lower than 320 "C (20% at 320 "C). Iron(II1) oxide (content, 7.1%) required even higher fusion temperatures (10% at 360 "C and 50% at 400 "C).
Literature Cited Asahara, T.; Kito, T.; Kato, Y.; Yamaye, M.; Yoshinaga, K.; Tsukita, N. Alkali Treatment of Coal. Ind. Eng. Chem. Prod. Res. Deu. 1983,22, 488-491.
Balcioglu, N.; Yilmaz, M. Molten Alkali-Alcohol and Molten Alkali Treatment of Lignita: A Comparative Study. Fuel Sci. Technol. Znt. 1990,8,689-697. Iki, S.; Masumori, K. Sekitan oyobi sono Shikenho (Coal and Its Test Method) Maruzen: Tokyo, 1951; Vol. 2, p 120. JIS (Japan Industrial Standard) M 8815 (methods for analysis of coal and coke ash), 1976. JIS (Japan Industrial Standard) K 0121 (general rules for atomic absorption spectrochemical analysis), 1982. Kasehagen, L. Action of Aqueous Alkali on a Bituminous Coal. Znd. Eng. Chem. 1937,29,600-604. Ohtauka, Y.; Wang, 2.; Tomita, A. A Study on the Removal of Mineral Matter from Coal by Alkali Treatment. Nenryo Kyokakhi 1987,66, 189. Probstein, R. F.; Hicks, R. E. Synthetic Fuels; McGraw-Hill Kogakusha Ltd.: Tokyo, 1982; Chapter 3, p 137. Srivastava, S. K.; Saran, T.; Sinha, J.; Ramachandran, L. V.; Rao, S. K. Hydrogen Production from Coal-Alkali Interaction. Fuel 1988,67, 1680-1682.
Wang, 2. Y.; Ohtauka, Y.; Tomita, A. Removal of Mineral Matter from Coal by Alkali Treatment. Fuel Process. Technol. 1986,13, 279-289.
Received for review May 14, 1992 Accepted October 5, 1992
