Document Yjne28woJd3remkV952w3ZwjK

Expanded plant with chaingrate stokers burns lignite hav ing 35% moisture and' only 7000 Btu. Monthly boiler and furnace efficiency is 76%. Furnaces have special watercooled arches and use overfire air from nine horizontal nozzles above the front arch By C C6IB10N, CfiM IngfftHr Canada Potkcn, Ltd St. Bonlloce, Manitoba Meat packing, like many other In dustrie*, expanded greatly during the war. The millions leading strenuous lives In the armed forces and In labor's, ranks needed more and more body building food. Moreover, canned and dehydrated meats and new packing house byproducts were developed along with an enormous and growing output of fats for glycerin and soap. As every plant was pushed to maximum produc tion, requirements of steam, power, air and refrigeration also increased. Canada Packers' Sl Boniface plant, one of the largest packing .houses in western Canada, soon faced serious problems because power-house equip ment could not meet growing demands. During the lean 1930's one 6000-kw electric-steam generator met practically all requirements. This unit was origi nally Installed to use off-peak power, available at low rates. Two venerable B&W straight-tube boilers, in semiretirement after, nearly-50 -years,- wereused only during the busy fail season. New Steam Generator. By 1940 it was obvious this equipment would not meet demands, so plana were made to add to the steam-generating capacity. In 1941 a new generator, rated 36,000 lb per hr, 130 pst, saturated, was installed in an extension to the boiler room. Surveys showed that the cheapest fuel available was Souris bug-dust, a lignite averaging ash, 33 to 35% moisture, 7000 Btu per lb. This higb-mbJsturo fuel is burned on a traveling-grate stoker. Furnace construction is conventional with a long ignition arch and refractory walls. This generator has forced* and in duced-draft fans, economiser, air heater, automatic combustion control A new COAL DUST IS ILIMIMATSD from the boiler room by on exhaust duct along bunjg bottom with intakes to each cool got* ond along cech stoker hopper. That'll^ operators wear white suits even though fine, dusty cool is distributed by o walgMon Burns Bug-Dust Lignif 160-ft cast-concrete stack was erected, provements. Refractory mamteqx large-enough to-take cate-ol expansion - costs had been high under the boy that was foreseen even then. loads carried. Also, the long pipriog This unit gave excellent service, often through the expanding plaat at severe overloads, as expansion taxed superheat advisable. Accordingly! boiler capacity to the utmost. Mean requested the designers to in while, rapid expansion in the twin cities waterwalls, watercooled archeag of Winnipeg and Sl. Boniface added a superheaters in the new units. problem. The electric utility no longer The designers, in turn, prep5S had excess power at peak periods, and new furnace to provide rear-areh;g warned that the electric-steam genera for lignite and a more open faff tor could operate during ofT-peaks only. throat. This design was develop^ Two Additional Units. Early in 1946 greater fuel versatility so others we surveyed steam requirement Peak than lignite could be burned, l(dl load had reached 98,000 lb per hour should be delays in coal with overages of 70,000 in the busy transportation. season. We therefore decided to scrap the two old straight-tube boilers and install two units of about the slxe of the new boiler. Duplicates were considered, Demolition of the old boilers March 1, 1946. The old boil*(j{|_ was extended and its roof raised form to the newer section. Erect^T but experience suggested certain im the new boilers started the fir*1 *! 98 (550) POWER $spisfl>b^j| fuel. Deflected by the front arch and the blast of air above it, llie flame passes back across the furnace again, toward the rear-tube bank, where a baffle turns it forward and upward once more to the first pass. Thus gas travel forms a rough "Z," giving plenty of room for thorough gas mixture and complete combustion. A test run on a bituminous coal of totally different characteristics from' lignite showed this furnace will burn It with fairly good results if necessary. Eoch new boiler consists of an upper drum 54 in. dia x 10 ft long, a 36-in. mud drum 11 ft long, with 198--2%-ln. and 121--3V4-in. steam-generating tubes, giving a total heating surface of 5072 sq ft including waterwalls. Water is supplied to sidewalls and front-arch tubes by 7%-in. square headers^Rear arch is cooled by extending the front two rows of rear tubes forward'and. downward around the arch, then back lo a rear waterwall header on lop of back wail. Furnace has a volume of 1680 cu ft, and coal is burned on a traveling-grate stoker with 140 sq ft effective grate area. Automatic combustion control regu lates forced- and indueed-draft dampers and stoker speed. Meters record steam pressure, feed temperature, gas temper ature in each boiler; economiser and . & MCTCRS AND CONTROL. Eoch boiler hoi outomotie combustion control, ond all iKrte controls are tied Into a matter regulator which coordinates the operotlon of oil Meters guide operators In mointalnlno high bolter performance ot all times sir-heater outlet, and air-temperature as well as ateamflow airflow .relation ship for each unit. An integrator on each boiler records steam production. Twelve-point draft At Efficiencies to 79% gages show draft pressure at the air-beater outlet, stoker-wihd-boxea, fur nace-uptake, economiser, and air pres*' sure in and.out of air healer. Puihbut* [ft`May. The first unit was ready for trials 'jkbySeptS. Svr, Trial Runt. Flirt trial runs, while Satisfactory to maoy respects, revealed Ew^me flsw* in gas circulation. Cases Wj stratified in the furnace and shot and a longer flame travel. This equip. ment increases boiler and furnace effi ciency nearly S%. At the same time, flyash carryover was greatly reduced. Finally, automatic combustion control of the overfire air, ton controls for Induced* and forceddraft fan and stoker motors are - mounted on the.meter panel. Modem Equipment.' All boiler-room equipment is as modern es possible with emphasis on dependability, maintenance of sendee and flexibility to meet widely up to the first' pass, bypassing !>'. *car furnace tube bank. Flyash 5R*<|Trik!rcr' olways a problem with ligjk*. te bug dust, was excessive. After mak- correlating air . volume to - the boiler * load, was worked out and applied. As far as 1 know, this is the first ap plication of overfire air jets to this type varying demands without sacrifice in efficiency. Goal is received in gondola care on a spur track, in front of the boiler room. nd studies of gas circulation j i . *Pplied a blast or blanket of over- air through a row of noales above front arch. installation. The highly satisfactory re sults exceeded expectations. In rear-arch firing, as how practiced in these furnaces, main air supply from Dumped directly into either of two grated track hoppers, 'it Is elevated by continuous-flow conveyors' into over head bunkers running the length of the M PreMute f about 11 in. the forced-draft ions enters the furnace room in front of the boilers. These * aupplled by a high-head fan well toward the grate's rear. Main, bunkers hold 220 tons, enough for ^fiimU*^ * ^ucl* an<f introduced into the flame, deflected forward by the long 48-hr operation under heavy demand. *nc natla between the rear arch, crosses the furnace from back An electrically driven 2-ton weigh larry tubes* This air sweeps the to front at an angle and strikes the bull- takes coal from any bunker gate- and keck of furnace above the nosed front arch. Radiant heal from delivers it to any of the three boilers. aauiing increased turbulence this flame dries and ignites incoming Ashes fall from rear of traveling : * September 1948 (SSI) .99