خرید بک لینک

مدل سفره عقد
اخبار بانک و بیمه
کانال تلگرام
درج آگهی رایگان
وقت سفارت ایتالیا
ویزای شینگن
خرید بک لینک ارزان
پایان نامه کشاورزی
پایان نامه رشته کشاورزی
پایان نامه معماری
پایان نامه رشته معماری
پایان نامه هنر
پایان نامه شیمی
پایان نامه کامپیوتر
پایان نامه اقتصاد
پایان نامه تاریخ
پایان نامه صنایع
پایان نامه حقوق
پایان نامه روانشناسی
پایان نامه علوم اجتماعی
پایان نامه جامعه شناسی
الهیات فقه و فلسفه
فایل ارشد پایان نامه
مرکز دانلود تحقیق
پایان نامه ارشد
حقوق جزا خصوصی
پایان نامه مدیریت دولتی بازرگانی
سایت ارشد پایان نامه
مشاوره و برنامه ریزی کنکور
پایان نامه برق قدرت الکترونیک
پایان نامه روانشناسی
پایان نامه رایگان
پایان نامه دانلود ارشد
پایان نامه های ارشد
پایان نامه ارشد
پایان نامه حسابداری دولتی مالی
پایان نامه عمران
پایان نامه های ارشد
دانلود پایان نامه
پایان نامه جغرافیا
پایان نامه دات نت
پایان نامه
پایان نامه ارشد
پایان نامه ها
مقاله
تست ارشد
دانلود پایان نامه
پایان نامه حقوق
پایان نامه
انجام پروژه متلب
تور تایلند
ماهنامه تیتر صبح
سرور آنلاین کانتر استریک

refractory

refractory
ورود شما به سایت کوچک مان را خیر مقدم عرض می نماییم.
به دلیل بروز بودن سایت لطفا از سایر صفحات وب هم دیدن نمایید.

تبلیغات هزینه نیست بلکه زمینه سازی برای معرفی وب خود به دیگران و درآمد زایی برای شماست .
سفارش تبلیغات سفارش تبلیغات سفارش تبلیغات سفارش تبلیغات

درباره وب

refractory, sunriserefractory
تبلیغات



 

The need of the glass manufacturers to maintain and improve the quality of glass and expand the service life of the glass furnace and the impact and influence of the oxygen-fuel combustion technology, promote the improvement of refractories and development of the new refractories.

Fused cast alumina block has been widely used in the crown of the oxygen-fuel furnace, especially when manufacturing high quality glass. Before the application of the oxygen-fuel combustion technology, only β alumina block is used in the superstructure of the melting furnace. Now both β fused cast alumina block and α-β fused cast alumina block can be used in the crown of the oxygen-fuel furnace for producing TV glass, float glass and borosilicate glass.

Fused cast AZS block has been successfully used in the crown for many years. It can be used at 1600℃ or 1650℃ and can withstand the cycle of cooling and heating well. Compared to fused cast AZS, fused cast alumina block can be used at 1700℃ and has better mechanical strength and thermal stability.

In the past, high chromium brick was mainly used for the production of reinforced glass and sometimes in the insulation glass furnace. Now it is increasingly used in some soda-lime glass furnaces. It has much better corrosion resistance to glass and can prolong the service life of throat. Besides the throat, it is also used in the end wall, the angle brick of the feeder port. However, the chromium may color the glass liquid, thus it can not be used in the white glass furnace. It was primarily used in the colored glass furnace, but now it has been successfully used in the transparent container glass furnace.

Low glass phase fused cast AZS block has been successfully used in the superstructure. The development of the oxygen-fuel combustion technology makes it find wider application in the superstructure. Since it contains a low amount of glass phase, it has better creep resistance and the amount of exuded glass phase has been reduced to a very low level.

Fused cast high zirconia block is a new type of refractory, mainly used in the glass contact areas in high quality glass furnace. It has a low potential of causing stones, knots and bubbles and can effectively reduce glass defects. It is also in some low alkali glass or hard borosilicate glass furnaces.


تاريخ : يکشنبه 22 آذر 1394 ساعت: 23:56 ا نویسنده : ADMIN ا
برچسب‌ها: Novel Refractories For The Glass Furnace, ,

دسته بندی : <-CategoryName->,



 In the glass furnace, walls of the regenerators are used to limit thermal losses. The main operating factors to be considered are temperature, repeated temperature cycling, airborne particulates, volatiles and load. Fuel and glass composition must also be considered when deriving the refractory specifications.

The walls in four zones as with checkers are subjected to different conditions: 
1) Top zone: from the crown skewbacks to one meter under first row of checkers;
2) Mid zone: from the end of the top zone to 1,000°C;
3) Condensation zone: from 1,000°C to 700°C;
4) Lower zone: from 700°C to the Bottom.

The operating conditions are the same as for the crown but with minor load. Low iron basic refractories with a high periclase content and high grade mullite (95-97 percent mullite) are suitable for this area. As far as basic refractories are concerned the operating temperature must be under 1,500°C (1,460-1,480°C) to avoid creep.

Provided the target wall is exposed to the same conditions as the other top zone walls, then the refractory material will be as for the rest of the top zone. However, in the event the target wall is subject to excessive waste gas impingement then fused cast AZS block is recommended.

Checkers protect the mid zone wall. Temperature and load are lower compared to the top area, thus basic refractories with 95 per cent MgO or a good mullite are suitable for this area.

Chemical corrosion is not as strong as in the checkers because bricks are protected by the masonry and only one side is exposed to the chemical attack. Load is higher than on the overhung zones, but temperature is lower. Periclase based refractories, mullite and sillimanite bricks are suitable for this application.

Characteristics of this area are: high load, low temperature and a reduced chemical attack. Basic materials with 90-92 percent MgO, mullite, sillimanite and 44 per cent Al2O3 “super duty” are suitable for this application.

The internal separation walls are fully immersed in the high temperature environment and therefore the operating conditions are severe. They must resist loading at high temperature, and thus they must have high values of refractoriness under load and therefore high creep resistance.

Basic materials are suitable within the temperature limits indicated in the top zone (1,460-1,480°C), while different grades of mullite according to the different zones of the separation wall can be used.

Zhengzhou sunrise refractory Co., Ltd. is a refractory supplier from China, specializing in various refractories for glass furnaces, such as fused cast AZS block, magnesia bricks, silica brick and mullite bricks.


تاريخ : يکشنبه 22 آذر 1394 ساعت: 23:54 ا نویسنده : ADMIN ا
برچسب‌ها: Refractory Application in the Walls of Glass Furnace Regenerators, ,

دسته بندی : <-CategoryName->,



Ceramic fiber module is made of ceramic fiber blanket by folding and compressing. Currently, it gradually becomes the first choice for the thermal insulation of industrial furnace linings.

Ceramic fiber module has white color and regular size. It can be directly fixed to the anchor nail on the steel plate of the furnace shell. It has good insulation performance and can improve the integrity of the furnace. It simplifies and speeds up the construction of furnaces and promotes the masonry techniques of furnaces.

It has many advantages over the ceramic fiber blanket.
1) During installation, after releasing the tying, the folded blankets can generate a huge stress, which makes them crowded together tightly without gaps.
2) The flexibility of ceramic fiber blanket can compensate the deformation of the furnace shell and reduce the construction cost. At the same time, it can make up the gaps caused by the thermal changes of the different components.
3) Since it has light weight and low thermal capacity, it can significantly reduce the energy cost during the temperature operation.
4) Flexible ceramic fiber blanket can withstand external mechanical forces.
5) It has good resistance to thermal shock.
6) The ceramic fiber lining requires no drying and maintenance. It can be put into use immediately after the construction is completed.
7) It has stable chemical properties. It is not eroded by acids, bases, water, oil and vapor, except phosphoric acid, hydrofluoric acid and strong base.

It can be used for the furnace lining insulation in the petrochemical industry, metallurgical industry, ceramic industry, glass industry, heat treatment industry and other industries.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope and yarn.


تاريخ : سه شنبه 10 آذر 1394 ساعت: 2:44 ا نویسنده : ADMIN ا
برچسب‌ها: Advantages of Ceramic Fiber Module, ,

دسته بندی : <-CategoryName->,



When selecting refractories for regenerator chambers serving natural gas fired furnaces producing soda lime glass, both the functions of the refractories and the operating conditions within the checkers should be taken into consideration.

As heat exchangers, checkers should have high thermal capacity and thermal conductivity. Basic refractories and fused cast refractories are the best solution.

However, refractory selection also depends on the operating conditions, while the operating conditions depend on the position. According to the temperature, checkers can be divided into four zones: Top zone (from the first row to 1,350℃), Mid zone (from 1,350℃ to 1,000℃), Condensation zone (from 1,000℃ to 700℃) and Lower zone (from 700℃ to rider arches).

Top Zone

High temperature and batches and dusts result in chemical attack and gradual corrosion of the basic refractory bricks. If refractories are magnesia bricks, the chemical attack is up to the CaO/SiO2 ratio in the waste gases. if the radio is low, forsterite (Mg2SiO4) will be formed, which results in fissures opening within the bricks. Subsequently, silica penetrates these fissures resulting in the familiar cubic breakdown of the upper checkers. If the CaO/SiO2 ratio in the waste gases is high, a liquid phase enters into the refractory causing deformation. The best solution is magnesia bricks with high Mg content, well developed MgO crystals and a direct bonded structure. Additionally, the refractories should have low iron to avoid FeO oxidation to Fe2O3 and vice versa (Fe2O3 reduction to FeO) with volume variations and resultant brick failure.

Fused cast refractories have no surface porosity thus they are resistant to the corrosive effects of waste gases and carryover and can be used in all the checker zones. Compared to sintered refractories they are more resistant to abrasion due to their dense and homogeneous structure thus they are suitable for the top zone where there is a strong carry-over. Fused cast alumina brick is recommended for its very limited glassy phase. No glassy phase means no exudation therefore no excessive bonding with carry-over thus minimizing the risk of blockages.

Mid Zone

This zone is protected by the top checker area and temperature level is lower, thus 96% MgO with low iron and fused cast AZS 33# are recommended.

Condensation Zone

This is another critical area. The waste gases contain alkaline sulphate and SO3 which will condense out in the 1,000-700℃ range. In presence of sodium sulphate, the predominance of Na2O or SO3 in the waste gases causes chemical attack. Periclase base refractories are not chemically attacked by sodium sulphate or sodium oxide but they strongly react with SO3 forming MgSO4 causing densification of the Structure.

The chemical attack, enhanced by the presence of vanadium pentoxide when using fuel oil, breaks up the refractory and the structure densification lowers thermal shock resistance. Viable substitutes for chrome bearing refractories, which have a high resistance to condensates but cannot be used for environmental reasons, are both the spinel (MgO·Al2O3) and refractories made by periclase (MgO) and zirconia (ZrO2) having good resistance against Na2O and SO3.

When firing with natural gas, since the SO3 quantity is low, basic refractories can be used. When fused cast material is used, fused cast AZS is recommended.

Low Zone

Super duty fire clay brick can be used in non severe working conditions. 90-92% magnesia brick is recommended when firing by natural gas. Fused cast AZS 33# is also used in this zone.


تاريخ : سه شنبه 10 آذر 1394 ساعت: 2:42 ا نویسنده : ADMIN ا
برچسب‌ها: The Selection Of Refractories For Regenerator Checkers In Soda Lime Glass Furnaces, ,

دسته بندی : <-CategoryName->,



When selecting refractories for regenerator chambers serving natural gas fired furnaces producing soda lime glass, both the functions of the refractories and the operating conditions within the checkers should be taken into consideration.

As heat exchangers, checkers should have high thermal capacity and thermal conductivity. Basic refractories and fused cast refractories are the best solution.

However, refractory selection also depends on the operating conditions, while the operating conditions depend on the position. According to the temperature, checkers can be divided into four zones: Top zone (from the first row to 1,350℃), Mid zone (from 1,350℃ to 1,000℃), Condensation zone (from 1,000℃ to 700℃) and Lower zone (from 700℃ to rider arches).

Top Zone

High temperature and batches and dusts result in chemical attack and gradual corrosion of the basic refractory bricks. If refractories are magnesia bricks, the chemical attack is up to the CaO/SiO2 ratio in the waste gases. if the radio is low, forsterite (Mg2SiO4) will be formed, which results in fissures opening within the bricks. Subsequently, silica penetrates these fissures resulting in the familiar cubic breakdown of the upper checkers. If the CaO/SiO2 ratio in the waste gases is high, a liquid phase enters into the refractory causing deformation. The best solution is magnesia bricks with high Mg content, well developed MgO crystals and a direct bonded structure. Additionally, the refractories should have low iron to avoid FeO oxidation to Fe2O3 and vice versa (Fe2O3 reduction to FeO) with volume variations and resultant brick failure.

Fused cast refractories have no surface porosity thus they are resistant to the corrosive effects of waste gases and carryover and can be used in all the checker zones. Compared to sintered refractories they are more resistant to abrasion due to their dense and homogeneous structure thus they are suitable for the top zone where there is a strong carry-over. Fused cast alumina brick is recommended for its very limited glassy phase. No glassy phase means no exudation therefore no excessive bonding with carry-over thus minimizing the risk of blockages.

Mid Zone

This zone is protected by the top checker area and temperature level is lower, thus 96% MgO with low iron and fused cast AZS 33# are recommended.

Condensation Zone

This is another critical area. The waste gases contain alkaline sulphate and SO3 which will condense out in the 1,000-700℃ range. In presence of sodium sulphate, the predominance of Na2O or SO3 in the waste gases causes chemical attack. Periclase base refractories are not chemically attacked by sodium sulphate or sodium oxide but they strongly react with SO3 forming MgSO4 causing densification of the Structure.

The chemical attack, enhanced by the presence of vanadium pentoxide when using fuel oil, breaks up the refractory and the structure densification lowers thermal shock resistance. Viable substitutes for chrome bearing refractories, which have a high resistance to condensates but cannot be used for environmental reasons, are both the spinel (MgO·Al2O3) and refractories made by periclase (MgO) and zirconia (ZrO2) having good resistance against Na2O and SO3.

When firing with natural gas, since the SO3 quantity is low, basic refractories can be used. When fused cast material is used, fused cast AZS is recommended.

Low Zone

Super duty fire clay brick can be used in non severe working conditions. 90-92% magnesia brick is recommended when firing by natural gas. Fused cast AZS 33# is also used in this zone.


تاريخ : سه شنبه 10 آذر 1394 ساعت: 2:41 ا نویسنده : ADMIN ا
برچسب‌ها: The Selection Of Refractories For Regenerator Checkers In Soda Lime Glass Furnaces, ,

دسته بندی : <-CategoryName->,



Silica bricks with identical chemical composition can have differing mineralogical compositions which can cause quite different behavior during use. Therefore, it is not always sufficient to evaluate silica bricks only by their chemical composition. It is essential to also consider the degree of transformation and the thermal expansion behavior of the bricks.

Silica brick contains cristobalite, tridymite and some residual quartz. The crystal phases each have a high and low temperature forms which can transform reversibly. The crystal structure of the individual SiO2 crystal phase can differ widely. This is of great importance during heating and cooling because of the change in the volume.

Quartz requires the smallest volume and the quartz glass the largest. During firing above approximately 900℃, quartz transforms into the other modifications and melt completely at 1725℃. It shows such a transformation at 573℃, tridymite at 117℃, and cristobalite between 225℃ and 270℃. The thermal expansion of cristobalite is considerably greater than that of the tridymite.

Because well transformed silica bricks contain little or no residual quartz, their behavior under the influence of temperature is largely determined by the ratio of cristobalite to tridymite. During heating up, silica bricks expand rapidly with the total reversible expansion being completed at around 800℃. Therefore they are insensitive to the temperature fluctuations above 800℃, but very susceptible below this temperature because of the sudden volume expansion. For this reason, sufficient time must be allowed for heating furnaces up to about 800℃.

During slow cooling , reversible volume decreases take place which are a result of the spontaneous transformation of the crystal structure from the high to the low temperature modification. The reversible and irreversible volume effects can cause considerable stress within the refractory brick structure.

During the firing process, the lime reacts with the quartzite components to form wollastonite. The matrix also contains very small quantities of calcium ferrite, hematite, magnetite, calcium olivine and hedenbergite, which are formed from impurities. These crystalline phases are the reason for the discoloration and spot formation on the silica bricks.

The degree of transformation of the bricks can be determined easily and accurately by the density of the residual quartz content. The density of a silica brick is lowest when the degree of transformation is farthest advanced.

The appearance of the bricks also indicates to the degree of transformation. The reversible thermal expansion also depends on the mineral composition. Tridymite and cristobalite do not expand linearly during heating but exhibit sudden changes in length both during heating and during cooling.


تاريخ : سه شنبه 10 آذر 1394 ساعت: 2:40 ا نویسنده : ADMIN ا
برچسب‌ها: Crystalline Phases And Transformation Of Silica Bricks, ,

دسته بندی : <-CategoryName->,


صفحه قبل 1 2 3 4 صفحه بعد
آرشیو مطالب
1395
1396
1395
1394
برچسب‌ها
<-TagName-> (<-TagCount->)
امکانات وب

آمار وبلاگ


تعداد آنلاين : 1
بازديد امروز : 36
بازديد ديروز : 0
بازديد هفته : 36
بازديد کل : 31366

فروش بک لینک
خرید هاست ارزان
دامین
خرید هاست
تبدیل وبلاگ به سایت
هاست
سرور اختصاصی
ایران هاست
سرور مجازی
هاست ایران
هاست ارزان
دامنه

رپورتاژ
12 Insults We Should Bring Back
Refractory
تنگ کردن واژن
دکتری پژوهش محور
پایان نامه
پارکت لمینت
چت شیراز
آموزش تعمیرات موبایل
آموزش تعمیرات موبایل
شبکه حرفه ای کسب و کار
درب ضد سرقت
CCCAM Server Fast Information
دوربین مدار بسته

لینک های مفید
خرید رپورتاژ آگهی, رپورتاژاگهی, بک لینک انبوه, بک لینک, تبلیغات بنری, خرید پاپ آپ, تبلیغات پست ثابت