182 ~EtWWlRGIA INTPRNATIONAL, Vol. 4, II. 4. iY78

search and Engineering on behalf of the soonsors, Carter oil [also an Exxon affiliate), the Electric Power Research Institute. Phillips Petroleum, and the US Department of Energy. The pilot plant will cost some E60m, and will be capable of liquefying 250 tons of coal a day. Construction is due to begin at any time. The plant, to be built next to Exxon’s Baytown refinery, will use and further develop the Exxon Donor Solvent coal liquefaction process which can produce about 2.5 to3 barrels of liquid products per ton of coal. The products are suitable for petrol blending stocks, low sulphur fuel oil and other fuel oils.

a FI

Latest approach to the application of ceramic fibres to line kilns is an analed strip system of blanket from Combu- stion Linings Ltd. Maximum air resistance is said to be achieved by this method since the fibre face is pointed in the direction of the air blast and therefore deflection is mi- nimal. Two products derived from these prin-- ciples are the Maximum Air Resistant Thermal Insulation Pads, or “Marti- Pads”, for the surface veneering of exi- sting furnace brickwork, and the 1s Marti Modules ~1, self-supporting square pa- nels, which can be used for walls, floors and roofs in new furnace design. (1 Marti-Pads 1~ are made in standard thickness from 25 to 150mm and mea- sure 3QOmm square. They are backed with an adhesive paper which keeps the strips in position. Fixing cement is applied to the exposed face and the paper wrapper burns off in the furnace heat. They can be used to repair brickwork which has cracked or deteriorated and it can be applied to new brickwork to reduce heat loss and improve efficiencv. Fuel savings of 14.9%’ were achieved from a 50 mm layer on an intermittent pottery kiln. The ~1 Marti-Modules 1~ are made from angle strips placed on the hot face and fixed with an adhesive cement to a centre insulation matrix of &fax insu- lating castable. Behind this core is a backing which provides rigidity and fix~, ing points. Each panel can be bolted a0 the next or a run of paneis can be threaded on to a metal rod and tightened from the end point. Standard panels are 610mm square with an overall thickness of 175mm. and weigh 27kg. Burner ports and flue outlets can be precast into position before delivery. Payback times of installation in terms of fuel savings can be as short as 10 ,to 42 weeks.

An ~~c0~\/e~ti~na~ a~~roacb to the de- sign of a new 11 biscuit kiln a~ (for firing

pottery) has given the unit

nearly treble the production capacity of the similar-sized kiln it replaces Whe- reas the old kiln, of traditional brick construction, had a 23-hour processing cycle, comprising 13 hours firing and 10 hours cooling, the new kiln, with a ce- ramic-fibre lining, requires only 9 hours oltogether: 7% hours firing and a much reduced cooling period of 1% hours. The new kiln was designed for pottery manufacturers J.E. t-leath Ltd. of Burs- lem, Stoke-on-Trent, England, by Tony Price, head of D.I.S. (Stoke-on-Trent) Ltd., also of Burslem. It is the first biscuit kiln lined completely with Triton Kaowool ceramic fibre made by Morga- nite Ceramic Fibres, this material’s low thermal mass and exceptional tolerance of thermal shock being primarily respon- sible for shortening the cycle. Another novel design feature is the hinged bench-like seal, also lined with ceramic fibre, running along each side of the kiln. The two seals swing up against the sides of the kiln cars after loading, minimisina heat-loss through the kiln bottom and protecting the bogie wheels of the cars from heat attack.-Below the seals the kiln is open to the atmosphere, supported on legs, to allow ingress of large volumes of air when the seals are reased. Ultra- swift cooling is further assisted by two large hinged dampers in the roof. An electronic controller operates -the seals and dampers automatically and programmes the gas/air-ratio settings of the four gas burners during the firing cycle, which is a follows: 1. Kiln atmosphere purged with a blast of air, with door and dampers open. 2. Burners ignited. 3. Two loaded kiln cars each carrying 3000 cups rolled in. Door and dampers closed, seals locked against the cars 4. 1200°C reached in 6 hours, followed by 1% hours ‘soak’. 5. Burners shut down, seals released, damoers ooened. Forced air coolina for 1% ‘hours ‘allows ware to be &moved. The burners, two in the door and two in the rear wall, are of a new recupera- tive type developed by The British Gas Corporation, rated at 150 KW (5 therms) each. The kiln has internal dimensions 4.22 m long x I,63 m wide x 1,93 m high (13 ft IO in x ft 4 in x 6 ft 4 in) and a capacity of 7,9 m3 [28O cu.ft.). The hot-face lining comprises 305mm(l-ft) squares of 25mm-thick [l-inch) Triton Kaowool High Duty Board il a rigid tom of ceramic-fibre with a continuous tem- perature limit of 1400°C. are 75 mm 13 in) thickness of Triton Kaowool Blanket and 50 mm (2 in) of Rocksil mineral wool. The jinina is an- chored by ceramic studs, located where the corners of the hot-face boards in- tersect. The burner blocks are clad with specially made ceramic-fibre shapes (Fig. 3), and the kiln cars also utiiise the material as an expansion medium and for insulation (Fig. 4) Construction of the new kiln was com- pleted in just 15 working days in July 1977, making use of the traditional ho- liday fortnight to minimise lost products ion. In a further 7 days the kiln was producing fired ware. Results from true meter readings bet- ween the aid c~~~v~~lt~~~a~ br~ck~~~~e~ kiln, whit was ~ern~~~~h~~, and the

new kiln that reolaced it show gas consumption savings of 45%, with, of course, the added benefit of the reduced firing and cooling cycles. Further information from: Morganite ceramic fibres ltd., Tebay Road, Bromborough, Wirral, Merseyside L62 3Pl-I, England.

The application of a thin layer of cera- mic fibre over existing refractory-brick furnace linings can cut fuel consumption dramatically, reduce cycle times in batch kilns, shorten start-up times and improve product quality by better heat distribution. The benefits are the result of the low thermal conductivity and low heat-storage capacity of ceramic i-ibre. ‘This technique is now marketed as the Fiberfrax L.O.R. (Lining Over Refracto. ry) system by The Carborundum Com- any. It enables older brick-lined furnaces and kilns, built when fuel costs were comparatively low, to be run economi- cally at today’s energy prices without involving heavy capital expenditure. Fre- quently substantial energy savings - 15% to 30% ---- are achieved by simply impaling one or more layers of Fiberfrax on anchors drilled in the existing brick- work. In a Yorkshire, England, brick-making kiln using a maximum firing temperatu- re of 115o”C, the installation of two i-inch (2.5.mm) layers of Fiberfrax Lo- Con felt over the existing lining has consistently reduced fuel costs by 15% over the last ;wo-and-a-half years. in Stoke-on-Trent. tngland, a manufacturer firing china biscuit at 1250°C in a gas fired intermittent kiln reports that cycle

time is reduced from 12 hours to 8 hours and that fuel savings total 30% follownig the installation of 2-inch (50 mm] Stackbond stick-on ceramic-fibre modules in Fiberfrax H over the exist- ing brickwork. In the USA, Carborundum’s LOR system has produced many instances of savings. For example, a company in Ohio firing 28.800 items of vitrified dinnerware daily in an ,112O”C hot zone has cut start-up time from 60 hours to 36 hours, and has metered fuel savings of 24 mij’ lion cu,ft. (68O.OOO m’) of gas per day - 15% of consumption. This was achieved ‘by facing the existing 480~mm [19-inch) layered hard-firebrick/~ermiculite/re~~” brick lining of their two 43-ft diameter (13-m) tunnel glost-firing kilns with a 2inch (so-mm) layer of 6-lb/ft’ [96-kg/ m? density Lo-Con ceramic-fibre felt. Using Fiberfrax f-l Durablanket, L.Q.R. in- stallation can withstand hot zone tem- perature up to 1380°C. The L.D.R. system has already been used for several installations in France, and The Carborundum Company can orovide details of installations through- out the metallurgical, glass and petro. chemical industries Whilst actual sa- vings will always depend on the overall operating efficiency of the furnace it is generally true to say that the sbo~t~r the firing time, the higher the likely savings will be, because ~~irl~~~urn heat absorption is an inherent q~~~~~t~ of ce- ramic fibre insulation.