One burner unit exists of the mobile burner with the extended nozzle, the combustion fan, regulation flap for the combustion air, the connecting air. Longer period of low temperature drying causes more even heat distribution resulting better refractory dry out. Drying refractory in steamgenerating boilers insulation. In the steamgenerating industry, refractory materials are used for filling gaps and openings to help keep the fire inside the fire box, for lining ash hoppers wet and dry that collect ash and slag, and for the protection of lower furnace wall tubes inside fluidized bed, cyclonefired, or refusederived fired boilers. Refractories ring the changes wahl refractory solutions. Table 1 compares installation times over a 24month life cycle for sifca nose blocks and a conventional refractory castable nose ring. Refractory has always been an integral part of steamgenerating boilers. Newly installed refractory re quire a carefully controlled initial heating. When mixed together these products exhibit a fast exothermic set and can be he heated at a much faster rate than conventional refractory products.
Unfortunately, standard refractory dry out schedules, provided by all refractory manufacturers with their products, are difficult to apply to refractory used on a steamgenerating boiler. These external burners are fired with light weight oilgas and will be installed in openings like manholes or doors. Refractory dryout is the controlled process of applying heat to a refractory lining to remove water from the lining system without causing damage to the refractory. Pdf secondary reformer refractory dry out operation prem. Drying out monolithic refractories refractories are heatresistant materials used for the retention of substances at high temperatures in furnaces, reactors and other processing units. Various capacity of oil and gas burners, including high velocity burners up to 5,000,000 kcalhr. The dryout cycle can be programmed into the control system. It is not intended as, and should not be taken as, a warranty of any kind, including but not limited to a warranty of. It is used to lay firebrick in places that are exposed to extremely high temperature. Refractory dry out the key to a long refractory life is a dryout using gccs high velocity gas combustion systems. Refractories are inorganic, nonmetallic, porous, and heterogeneous. It is not uncommon for moisture to be absorbed by the refractory during final stages of inshop fabrication, transit to the job site, and before the upstream combustion products are first passed through the unit. Midland, texas, usa abstract time is often lost during startup of new cryogenic gas plants due to inadequate planning and execution of dry out.
Proper refractory dry out is key to optimum service life. North american refractory and dryout fives in combustion. Refractory experience in circulating fluidized bed combustors. Due to the previously mentioned characteristics, nonwater soluble product is the preferred choice for clay flue installations that may vent gas or oil appliances or in any. The refractory mortar is utilized only to build fire places and shall not be applied on hot faces. Unfortunately, standard refractory dryout schedules, provided by all refractory manufacturers with their products, are difficult to apply to refractory used on a steamgenerating boiler. In addition to being resistant to thermal stress and other elements induced by heat, refractories are usually required to withstand physical wear and corrosion. Thermal stresses will be produced if heating rate is too rapid. For many refractory installations, the dryout portion of the project can be the most frustrating. Any deviation from this program may result in the refractory cracking or even failure falling down. Controlled heating, through these reactions ensures maximum strength.
May 22, 2019 dry out is the initial heating of castable lining in order to remove retained water from within the refractory castable without adversely affecting its structure or physical properties. There have been significant improvements in castable and plastic refractories over the past 35 years through the selection of better raw materials, improved particle sizing, additives, improved bonding materials and improved manufacturing processes and placement methods. The curing and firing of refractory castables densecretes and litecretes. The apparent porosity is the volume of the open pores, into which a liquid can penetrate, as a percentage of the total volume of the refractory. Refractory dryout our expertise in these areas ensures maximum flexibility and minimum downtime. For the dryout of a refractory lining external high velocity burners are used. Pdf magnesia refractory dryoutmanaging the risk of hydration. Installed refractory linings and castings containing calcium aluminate cement binders should be cured prior to drying. For the dry out of a refractory lining external high velocity burners are used. It is the largest temperature drying causes more even heat distribution conglomerate in the west africa and one of the largest in resulting better refractory dry out.
Pdf drying stages during the heating of highalumina. These standard dry out schedules are generic and require temperature monitoring rarely found at power plants, where monitoring. Explosive spalling of low cement castable refractories a. The worst case scenario is having to bring the sru down shortly after acid gas has already been. K licensee hotwork is the pioneer of the convective heating process, which simplifies refractory dry outs and heatups. Dry out must not be confused with curing, which is the process of keeping the refractory material wet or the surrounding atmosphere humid for.
Refractory, or the lining utilized on the interior of rotary kilns, is a critical component in ensuring process efficiency and prolonging the life of a rotary kiln. The correct application of heat curing and controlled release of water in the castable is very important for the life time. K licensee hotwork is the pioneer of the convective heating process, which simplifies refractory dryouts and heatups. Refractory dry out procedures boiler furnace scribd. Refractory dry out procedures free download as pdf file. Important considerations for refractory dryouts, startups. It is very much important that proper dry out of secondary reformer refractories as water is the common solvent for mixing refractory material. There are two main types of refractory mortars available. Api 936, refractory installation quality control inspection and testing monolithic refractory linings and materials, provides installation quality control guidelines for monolithic refractory linings and may be used to supplement owner specifications. I am agree with ts1979, every refractory lining especially for monolithic castable lining has to cured for 24 hours minimum before dryout process. Thermbonds formula series refractory products consist of two parts, a dry formulation and a liquid activator.
Cobane, vice president and general manager hotwork usa lexington, kentucky, usa abstract as monolithic refractory products have become more technically sophisticated and their usage increased, the end userconsumer is more often requiring a turnkey project that. It looks like the work is completed, the vessel looks brand new, and there are always intense pressures to fire it up and get production ramped back up after a. The api 936 refractory personnel certification examination is designed to. Since calcium aluminate bonded low cement castable refractories were first developed, explosive spalling during dryout has been an ongoing problem for refractory manufacturers, installers, the end user and the service company hired to perform the initial dryout.
Here, well discuss everything you need to know about refractory, including how it works, the different types, and best practices for preventative care. The requirements for high quality lining is the adequate drying of the material. Refractory dryouts national heat treatment division. Astm f1097 17 standard specification for mortar, refractory.
National heat has over ten years of experience undertaking refractory dry outs for many clients around australia. Drying out monolithic refractories gulf coast combustion. Discover our comprehensive product range, going beyond monolithics to cover all your refractory needs. Refractory curing industrial professionals cheresources. With gulf coast combustions refractory dry out knowledge and expertise, you and your clients will get a longlasting life on your refractory. Secondary reformer refractory baking and dry out cycle requires very slow and controlled heating of refractory.
Rcf is a refractory ceramic fibre material, also know as asw alumino silicate wool. Whilst the values and application information in this product data book are typical, they are given for guidance only. Sulphur plant and tail gas treating unit startup and. An effective dry out procedure, and one carried out in compliance with the manufacturers specification, is the key to ensuring that a furnace operates to both the manufacturers specification and the operators expectations. The calderys range includes selfflowing castables, dry gunning and shotcreting materials, bricks, ramming and plastic mixes, dry vibrating mixes, taphole clays, injection and grouting products, prefabricated shapes, and more. The refractory material was not normally thermally cured at the factory. Boiler refractory dryout courtesy of rentech boiler systems. Pdf magnesia refractory dryoutmanaging the risk of.
Our refractory dry out services is consist for the following. The secondary reformer having monolithic refractory material contain water or water based liquid which are needed to place the material and help the setting. Heating procedure for castable refractories kiltas refrakter. You should apply our company for the different refractory labels, amounts and widths. Dry out design considerations and practices for cryogenic. Boiler refractory dry out is to ensure proper drying, curing of refractory applied on furnace and other components. Combustion air blower with capacity up to 5000 nm3hr.
While heating, there must be free air flow over the system to ensure. For this comparison, both options begin with the removal of a conventional castable nose ring. Harbisonwalker handbook of refractory practice disclaimer. If the initi al heating is carried out to rapidly and or with local hot spot, then diffrent rates of. Dry out design considerations and practices for cryogenic gas plants joe t. Exporter of refractory dryout services refractory dry out of incinerator services, refractory dry out of pre heater of cement plant, thermal stabilization of turbine rotor and refractory dryout of convection and breaching section.
Dry out procedures for refractory must be completed as per the vendors instruction, which will include a temperature ramping and holding program. The curing and firing of refractory castables darley firebrick. The information presented in this book is for general educational use only. These standard dryout schedules are generic and require temperature monitoring rarely found at power plants, where monitoring. Heatingup for drying to the operational temperature of the installed monolithic refractory lining shall be carefully carried out because rapid heating causes cracks. Ammonia and urea complex important that proper dry out of secondary reformer includes. Secondary reformer refractory dry out operation ijert. While heating, there must be free air flow over the system to ensure removal of moisture. Materials, equipment, and personnel are qualified by the methods described, and applied refractory quality is closely monitored based on. In most industries it has become widely accepted, the only truly effective means of drying out and heating up refractory is to deploy a heat source, passing large volume of hot gases over the refractory surface, providing an even temperature distribution and re. Api certified 936 refractory personnel must have knowledge of installation, inspection, testing and repair of refractory linings. Magnesia refractory dryoutmanaging the risk of hydration article pdf available in journal south african institute of mining and metallurgy 1116. Curing is necessary to prevent moisture loss during the setting of the material.
New challenges have been identified over recent decades regarding the increasing complexity of the dry out step of refractory castables, mainly due to the advances on the particle size. A high velocity hot air burner is recommendable for heatingup. Pdf secondary reformer refractory dry out operation. Formula series dry formulations are mixed only with formula series liquid activator. Drying or the first heating of the system with a refractory material lining is therefore of great importance.
Refractory mortar is a specially engineered mixture of sand, calcium aluminate, cement, and fireclay. This necessitates another sru outage to affect repairs and another dry out procedure, costing another 4 to 6 days of downtime. Nonwater soluble refractory mortar is the only refractory mortar that should be used in outdoor applications. A refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Two angled, offset, highvelocity burner heads direct the flames and hot gases to the extreme ends of the car or enclosure while producing circulation patterns for optimum drying, heating and cycle control. Everything you need to know on rotary kiln refractory. This property is important when the refractory is in contact with molten charge and slag.
Pdf in 2002 the commissioning of an ilmenite smelter on the north coast of south africa was extended by three months due to the failure and. Standard specification for mortar, refractory high. Longer period of low temperature drying causes more even heat distribution. Drying refractory is critical for strong, longlasting refractory applications. Speeding up the process can and has resulted in refractory failures leading to hot spots on the metal coverings after firing of the mainburner.
Materials, equipment, and personnel are qualified by the methods described, and applied. I am agree with ts1979, every refractory lining especially for monolithic castable lining has to cured for 24 hours minimum before dry out process. It does not contain recommendations for any particular refractory for any particular use. Premixed refractory mortars may wash out even after drying. Dry out, also referred to as bake out, is the process for removing both the mechanical water added during the mixing process and chemical water originally added in manufacturing from the refractory. Jun 10, 2002 the combined efforts of refractory manufacturer, installer and dry out contractor result in optimal refractory performance. Refractory dry out services is available through hotworks u. Dry out is the initial heating of castable lining in order to remove retained water from within the refractory castable without adversely affecting its structure or physical properties.
The firewagon mobile system is easily transported to any location where temporary heating is required. The refractory usually undergoes considerable chemical changes, during initial heating. It is very much important that proper dry out of secondary reformer refractories. This dry out program is given for the average amount of material as an information guide. Water is a commonly used ingredient, which is used to mix mortars, rams, castables, cements that is used for installation. By utilizing stateoftheart equipment, including digital process controllers, fully proportional fuel actuators, and solidstate features, our engineers are able to provide flexible service that meets the most demanding of specifications. The values and the information given are subject to. The excess air burner is particularly suited to the application of high excess air combustion to dry out refractory. Dry out, also referred to as bake out, is the process for removing both the mechanical water added during the mixing process and chemical water originally. It is very much important that proper dry out of secondary reformer refractories as water is the common solvent for mixing. Drying refractory in steamgenerating boilers insulation outlook. The combined efforts of refractory manufacturer, installer and dryout contractor result in optimal refractory performance. Harbisonwalker handbook of refractory practice 2005.
Refractory mortar a selection guide whitacre greer pavers. They are typically composed of oxides of the following materials. Refractory dryout is the controlled process of applying heat to a refractory lining to remove water from the lining system without causing damage to the refractory materials. Pdf drying stages during the heating of highalumina, ultra. The onesided drying of monolithic refractories is an extremely complex transient heat and mass transfer phenomenon which includes chemical reactions throughout the. Refractory dryout procedure the refractory material was not normally thermally cured at the factory. To optimise the dryout time of your installation, calderys offers a full range of formulations.
488 1195 1055 155 1308 1422 1553 324 1097 1124 552 75 109 30 444 1349 752 1502 1469 476 405 1256 1183 760 277 866 166 1056 312 1022 1483 226 570