rotary kiln lime kiln cement kiln rotary dryer rotary cooler

lime kiln-rotary kiln,rotary dryer_hongke heavy machinery co.,ltd

lime kiln-rotary kiln,rotary dryer_hongke heavy machinery co.,ltd

Energy-saving and environmental protection active lime rotary kiln production line, the main equipment includes vertical preheater, transfer chute, rotary kiln, vertical cooler, multi-channel pulverized coal combustion device and other equipment. The whole system has high automation, high labor productivity and good quality of lime products. It is an advanced production system in the field of active lime production.

We are a professional rotary kiln manufacturer in China, providing flowchart and installation service. According to different fuels, rotary kiln can be classified into gas-fired rotary kiln, oil-fired rotary kiln and coal-fired rotary kiln. It is widely used for different materials with a processing capacity of 180-1, 000 tons per day, a dimension of2.540m-4.868m and cement production capacity of 50-1000t/d, being easy to operate and durable in use.

Active lime kiln is a type of rotary kiln and it is the main equipment used for calcining active lime. This equipment is mainly composed of cylinder, supporting device, supporting device with catch wheel, transmission device, lubrication device, mobile kiln head and sealing device at the end of the kiln with the advantages of simple structure, reliable operation and easy control of the production process.

Active lime kiln is equipped with advanced structure. The vertical pre-heat equipment can improve its pre-heating effect effectively with low-pressure loss, and the in-kiln decomposition rate of the pre-heated limestone can reach 20-25% and the 10-15mm fine particle limestone materials can be directly used.

This active lime kiln(limestone rotary kiln) adopts combined type scale sealing to ensure that the air leakage factor is less than 10%. Compound type refractory matter is adopted to reduce the radiant heat loss. The infilling type circular or square vertical cooler which can be divisionally ventilated can make the temperature of the lime cool that is discharged from the cooler to 80+ of the environment temperature for the convenience of transportation and storage, and it can also pre-heat the in-kiln secondary air to more than 700 to make full use of the waste heat and save energy.

grinding mill,ball mill,bag filter,rotary dryer,rotary kiln,dry,cement plant,lime plant,gypsum plant- tjie company

grinding mill,ball mill,bag filter,rotary dryer,rotary kiln,dry,cement plant,lime plant,gypsum plant- tjie company

TJIE Compant the main products ofthe company includepreheater of lime equipments, calcinations rotary kiln,shaft type cooler, grate cooler, cyclone preheater of the cement equipments, cement burning kiln more...

cement rotary kiln, rotary kiln | cement kiln | agico cement

cement rotary kiln, rotary kiln | cement kiln | agico cement

Cement Rotary kiln, is one kind of lime kiln, belongs to building material equipment. The rotary kiln has wide applications, such as metallurgy, chemical industry, cement, refractory materials, lime, environmental protection and other industries.

Cement rotary kiln, also called clinker kiln, can be divided into dry-process cement kiln and wet-process cement kiln according to the cement production technology. Dry-process cement rotary kiln is mainly used to calcine cement clinker. As the core equipment of NSP cement production line, cement rotary kiln is consist of shell, supporting device, transmission device, lubrication device, moving kiln head, sealing device for kiln tail, burning device and etc. dry-process cement rotary kiln has advantages of simple structure, reliable operation and easy to automatic control in the cement production line.

AGICO Cement is one of leading cement plant manufacturers offers cement kiln and other cement equipment, our cement rotary kiln has been widely applied to many cement plant. Based on 60+ years experience and advanced production equipment, we can provide EPC project and custom-designed solution to cement manufacturing.

Cement rotary kiln is a piece of cement equipment with strong durability, also plays a vital role in the cement plant. If you find any problem in the operation, solve it immediately. In general, the maintenance of rotary kiln is a complex process, here are some tips will be helpful.

First of all, check the fire hole of the rotary kiln is closed or not, ensure the close state to avoid too much cold air. Then, check the windshield of the burner at the kiln door is close to the kiln door. If the air leakage is not closed, it should be pushed to the position of close contact with the kiln door. Third, check the door cover of rotary kiln, if there is the phenomenon of positive pressure ash, should inform the central control to adjust properly. Finally, remember to check air leakage or wear out the phenomenon of resistant material, when you find the above problems, promptly inform the relevant leadership to deal with them.

Check the fish scales sealed in the kiln head, and then check the fitting condition of the fish scales in the rotary kiln and friction ring. If there is any bad condition such as non-fitting, the weight should be adjusted by tightening the device to make it fit. If there is too much aggregate in the reliable rotary kiln, the discharging pipe should be adjusted timely. After that, check the wear condition of the friction ring of rotary kiln. If the friction ring is found to be badly worn or worn out, replace it.

Check the cooling air at the kiln head, and then check the friction between kiln head and the kiln door cover. In order to ensure safety, check the oil film contact of the supporting wheel shaft and thrust plate one by one. Check oil level, oil scoop and oil distribution of rotary kiln. Next, check whether there are impurities, water droplets, oil leakage, collision, loosening and other abnormal conditions, if necessary, the temperature can be measured and control.

The service life of rotary kiln is affected by many factors, such as quality, regular maintenance, etc. AGICO CEMENT ensures the quality of the rotary kiln by strict quality control and advanced technology. Besides, regular maintenance can prolong the useful life of your rotary kiln.

Yes, in order to prevent cold air from entering the rotary kiln and smoke dust from spilling out of the cylinder, the rotary kiln is equipped with a reliable sealing device for the inlet end (tail) and an outlet end (head) of the cylinder, ensuring the sealing performance of the rotary kiln.

The cement rotary kiln produced by AGICO has been optimized and added with e dust filter products for environment protection, which is a new type of environmental protection equipment to reduce the environmental pollution caused by industrial production.

rotary kiln-rotary kiln,rotary dryer_hongke heavy machinery co.,ltd

rotary kiln-rotary kiln,rotary dryer_hongke heavy machinery co.,ltd

We are a professional rotary kiln manufacturer in China, providing flowchart and installation service. According to different fuels, rotary kiln can be classified into gas-fired rotary kiln, oil-fired rotary kiln and coal-fired rotary kiln. It is widely used for different materials with a processing capacity of 180-1, 000 tons per day, a dimension of2.540m-4.868m and cement production capacity of 50-1000t/d, being easy to operate and durable in use.

Through technical renovation, the advanced hydraulic thrust roller device, the plunger pump with high measuring precession, variable speed adjusted valve, graphite block sealing device and advanced technologies of other countries has been adopted for the manufacturing of calcining system equipment of rotary kiln. In order to improve automation degree, the industrial TV at the kiln head has been used for monitoring of kiln; the simulation phosphor screen has been used for display of process flow, and the infrared scanning system has been adopted for calcining zone to directly reflect the burning conditions on the computer. With the utilization of these new technologies, it is directly related to vision, convenient for operation and reliable in use. Therefore, the thermal condition can remain in a stable state and the running rate of equipment may be improved. Compared to the same size of the equipment, its running rate has been increased more than 10%, and productivity has been increased 5-10% and heat consumption has been reduced to less than 15%.

cement rotary kiln,rotary cement kiln-china hongxing machinery

cement rotary kiln,rotary cement kiln-china hongxing machinery

Cement kilns are used for the pyroprocessing stage of manufacture of Portland and other types of hydraulic cement, in which calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium silicates.

The rotary cement kiln belongs to building equipment such as chemical rotary kiln and active lime rotary kiln. According to different materials, there are cement kiln, metallurgy chemical kiln and lime kiln. Cement rotary kiln is widely used for calcining cement clinker and there are two types for cement production: dry cement kiln and wet cement kiln.

The materials to be burnt get into the stove from the higher end of the cylinder. Due to the slope and slow rotation of the cylinder, the material moves around from top to bottom along the axis to finish its process. At last, the finished materials get into the cooler through the burner hood. The fuel gets into the kiln through the head of the kiln. The waste gas will be discharged from the end of the kiln after exchanging heat with the materials.

In the mining production process, there are many types of rotary kilns. According to the firing methods of the kiln, it can be divided into direct fired rotary kiln and indirect fired rotary kiln; according to the processing methods, it can be divided into dry process rotary kiln, wet process rotary kiln and dry and wet types rotary kiln.

In addition, Hongxing Machinery now has researched and developed a cylinder rotary kiln which has a cylinder drum, thus improving the production capacity of the machine and reducing the energy consumption. And what is more, the clay rotary kiln now also has wide application range in the cement making, building materials and clay manufacturing industry.

Product specifications(m) Kiln dimensions Capacity(t/d) Rotation speed(r/min) Motor power(kw) Total weight(t) Note Diameter(m) Length(m) Obliquity(%) 2.540 2.5 40 3.5 180 0.44-2.44 55 149.61 Kiln with shaft cyclone preheater 2.550 2.5 50 3 200 0.62-1.86 55 187.37 ---- 2.554 2.5 54 3.5 204 0.48-1.45 55 196.29 ---- 2.742 2.7 42 3.5 320 0.10-1.52 55 198.5 ---- 2.844 2.8 44 3.5 400 0.437-2.18 55 201.58 Outside disassemble kiln 3.045 3 45 3.5 500 0.5-2.47 75 210.94 ---- 3.048 3 48 3.5 700 0.6-3.48 100 237 Outside disassemble kiln 3.060 3 60 3.5 300 0.3-2 100 310 Alumyte-alumina forge kiln 3.250 3.2 50 4 1000 0.6-3 125 278 Outside disassemble kiln 3.352 3.3 52 3.5 1300 0.266-2.66 125 283 Kiln with preheater precalcine 3.554 3.5 54 3.5 1500 0.55-3.4 220 363 Kiln with preheater precalcine 3.670 3.6 70 3.5 1800 0.25-1.25 125 419 Generating kiln for using ofterheat 4.056 4 56 4 2300 0.41-4.07 315 456 Kiln with preheater precalcine 4.060 4 60 3.5 2500 0.396-3.96 315 510 Kiln with preheater precalcine 4.260 4.2 60 4 2750 0.4-3.98 375 633 Kiln with preheater precalcine 4.360 4.3 60 3.5 3200 0.396-3.96 375 583 Kiln with preheater precalcine 4.566 4.5 66 3.5 4000 0.41-4.1 560 710.4 Kiln with preheater precalcine 4.774 4.7 74 4 4500 0.35-4 630 849 Kiln with preheater precalcine 4.874 4.8 74 4 5000 0.396-3.96 630 899 Kiln with preheater precalcine 5.074 5 74 4 6000 0.35-4 710 944 Kiln with preheater precalcine 5.687 5.6 87 4 8000 Max4.23 800 1265 Kiln with preheater precalcine 6.095 6 95 4 10000 Max5 9502 1659 Kiln with preheater precalcine

Product specifications(m) Capacity (t/d) Rotation speed(r/min) 2.540 180 0.44-2.44 2.550 200 0.62-1.86 2.554 204 0.48-1.45 2.742 320 0.10-1.52 2.844 400 0.437-2.18 3.045 500 0.5-2.47 3.048 700 0.6-3.48 3.060 300 0.3-2 3.250 1000 0.6-3 3.352 1300 0.266-2.66 3.554 1500 0.55-3.4 3.670 1800 0.25-1.25 4.056 2300 0.41-4.07 4.060 2500 0.396-3.96 4.260 2750 0.4-3.98 4.360 3200 0.396-3.96 4.566 4000 0.41-4.1 4.774 4500 0.35-4 4.874 5000 0.396-3.96 5.074 6000 0.35-4 5.687 8000 Max4.23 6.095 10000 Max5

lime kiln - an overview | sciencedirect topics

lime kiln - an overview | sciencedirect topics

Lime kiln dust (LKD) and cement kiln dust (CKD) are by-products of manufacturing and processing of lime and cement, respectively. CKD contains mostly dried raw materials such as limestone, sand, shale, and iron ore. Nearly 4 million tons of CKD is disposed of every year in the United States (Miller and Zaman, 2000). Due to its pozzolanic activator attribute, CKD has been successfully implemented in road soil stabilization (Miller and Azad, 2000). CKD creates a low-ductile asphalt binder, waterproofing, and protection. CKD-treated soils exhibit reduced liquid limit and reduced plasticity indices.

CKD inclusion in soil increases unconfined compressive strength, stiffness, and durability compared to untreated soils (Miller and Azad, 2000). Although LKD and CKD additives are not considered hazardous by environmental regulatory agencies, proper supervision and handling are needed when these additives are used in the field application.

The lime kiln calcines the calcium carbonate in lime mud to produce quicklime. Several modifications are possible to reduce energy consumption in the kiln. High-efficiency filters can be installed to reduce the water content of the kiln inputs, thus reducing evaporation energy. Higher-efficiency refractory insulation brick or chains can be installed to increase heat transfer in the kiln. Heat can also be captured from the lime and from kiln exhaust gases to preheat incoming lime and combustion air. Average savings achieved by these measures is approximately 0.46GJ/t pulp (Elaahi and Lowitt,1988; Grace,1987; Grace etal.,1989; Byrne and Larsen,1997; Lewko,1996; Pearson and Dion,1999). These improvements can also improve the rate of recovery of lime from green liquor. This will reduce the plants requirement for additional purchased lime. Based on an analysis of kiln modifications in cement production, Martin etal. (2000) assumed an investment cost of $2.5/t pulp. One study indicated that newer high-performance refractories can lead to lime kiln energy savings of up to 5%. Heat can also be recovered from the lime and from kiln exhaust gases to preheat incoming lime and combustion air (Kramer etal.,2009).

Materials contributing to air pollution include particulate matter from the boilers, lime kiln, and smelt dissolving tank; gaseous combustion pollutants such as carbon monoxide, NOx, and volatile organics from power boilers, recovery furnaces, and the lime kiln; odor consisting of reduced sulfur compounds in the kraft process arising from the digesters, evaporators, recovery boiler, smelt dissolving tank, and lime kiln; sulfur dioxide from the recovery furnace and boilers using fuel containing sulfur; and volatile organic chemicals from miscellaneous sources. In the sulfite process the primary pollutants are organics, oxides of sulfur, and particulates.

Lime is produced by calcining limestone at 825C in a lime kiln. The cost of this processing is reflected in the cost of the lime produced which is considerably more than that of limestone. The cost of transporting lime is also higher than that of limestone as lime must be protected from moisture. Karlsson and Rosenberg (1980a) estimate the cost ratio of lime to limestone on a molar basis to be between 2 and 4 depending on the transportation distance.

Lime has certain advantages over limestone in FGD applications. Cases of pH instability have been reported for limestone due to its relatively slow rate of dissolution. Limestone has a greater liquid-side resistance to mass transfer. It is also claimed that an unsaturated mode is more readily attained with lime (Karlsson and Rosenberg, 1980a). Despite these relative advantages FGD systems based on lime are becoming less popular than those based on limestone. Recent advances in the reliabilities of both lime and limestone systems have resulted in the cost of reagent being the overriding consideration. Of the plants under construction or contracted in the USA twice as many are based on limestone than on lime. Very few, if any, lime systems are under construction for projected plants (Karlsson and Rosenberg, 1980a).

Whether lime or limestone is employed, efficient utilisation of reagent is important from an economic point of view. Single loop, calcium based FGD systems must operate at pH values of about 6 to 6.5 to obtain adequate removal of SO2. The concentration of reagent, particularly when using limestone, in the solution at these values of pH can be as low as 2 to 4%. At these low solubility values part of the reagent may be discharged with the slurry. When 90% or greater removal of SO2 is required limestone utilisation may be as low as 70% (Braden, 1978) but is typically between 75 and 90% (Karlsson and Rosenberg, 1980a). With double loop operation reagent utilisation approaches 100% because conditions are such that any unused reagent discharged from the absorber loop is dissolved in the quench loop.

As of January 1980 there was a total of 35 680 MW of plant in operation or committed to limestone or lime scrubbing processes in the USA. This represented over 70% of the total FGD capacity in the USA. Operating and maintenance experience is well documented (e.g. Spring, 1980; Hewitt and Saleem, 1980).

From the fuel requirement point of view, rotary kilns are the most flexible of all lime kilns (Oates, 1998). They are successfully fired with natural gas, fuel oil, and pulverized fuels of all types including coal, coke, and sawdust. According to Boynton (1980), the United States is by far the world's leader in rotary kiln lime production with about 88% of its commercial and about 70% of captive plant capacity provided by kilns. The conventional rotary lime kiln has a length-to-diameter (L/D) ratio in the 3040 range with lengths of 75500ft (22.7152.5m) and diameter of 411ft (1.23.3m). Lime kilns are usually inclined at about 35 slope with material charged at the elevated end and discharging at the lower end. The degree of fill is relatively deep, about 1012%. Owing to its low thermal conductivity, limestone with a large diameter of about 2 in (5cm) results in higher effective bed heat conduction than smaller stones. The larger feed material sizes tend to have larger pore volume in the bulk and thereby maximize the particle-to-particle heat transfer, which is usually dominated by radiation at the dissociation temperatures. The smaller feed stones tend to pack themselves upon rotation and render the bed a poor conductor of heat. For many years, most long kilns operated with deplorable fuel efficiencies because of poor or lack of heat recuperation such as coolers and preheaters (Figure10.4) with thermal consumption as high as 1215 millionBtu/ton (33364170kcal/kg) of lime. Thanks to ingenious heat recuperation systems such as coolers, preheaters, and lifters, today, thermal efficiencies of rotary lime kilns are in the 68 millionBtu/ton range (16682224kcal/kg), using fuel at about half the rate of early long kilns.

Some rotary lime kilns operate under reducing conditions by curtailing the combustion air to substoichiometric levels so as to volatilize any sulfur that may be in the limestone in order to meet the stringent sulfur specifications imposed by steel and chemical users. For most operations except for dead burnt dolomite, the burner tip velocities can range between a low of 25m/s and a high of about 60m/s. These are significantly lower than the velocities of cement kilns, which operate around 80100m/s. The momentum ratio and associated CrayaCurtet parameter is usually lower than 2, which means that the burner jet recirculation will have eddies and that fuel/air mixing is moderate and the flame is less intense than that in dead burnt dolomite kilns or cement kilns. A simple heat and mass balance for the kiln section of a lime-making process is shown in Figure10.5.

Borate autocausticizing makes it possible to produce sodium hydroxide directly in the recovery boiler and improves the lime kiln and recausticization operations by reducing causticizing loads and the amount of lime processed through the system. The major function of the recausticizing plant in a pulp mill is to regenerate the caustic. Caustic is typically recovered from the spent pulping chemical in the following stages:

Autocausticizing could be an attractive alternative for kraft mills because it allows higher caustic production without increasing lime demand and can even eliminate lime demand (Kochesfahani and Bair,2002).

The partial borate autocausticizing process occurs when sodium borates are added to the kraft liquor at substoichiometric levels (Bjrk etal.,2005). A portion of the sodium carbonate is causticized in the recovery boiler. The causticization of the remaining sodium carbonate is completed in a conventional recausticizing plant of the pulp mill with a reduced quantity of lime. The technology may appear as an attractive option particularly for kraft pulp mills where incremental causticizing and lime kiln capacity are required. Mill-scale trials have shown that there are no major side effects on the mill operations. The major findings of the studies suggest that borate present in cooking liquor presents several advantages (Table11.19).

Borate autocausticizing technology uses Neobor, a form of sodium borate to replace lime. Each ton of Neobor added to the pulping process replaces 10 to 30 times its weight in lime (RTM,2010). The main autocausticizing reaction that occurs in the recovery boiler is between sodium metaborate and sodium carbonate in the molten smelt, which forms trisodium borate. The trisodium borate reacts with the water in the smelt-dissolving tank to form sodium hydroxide and regenerate sodium metaborate (Bjrk etal.,2005). Sodium metaborate stays in solution and circulates through the chemical recovery cycle to continue forming caustic in the recovery boiler. The borate compounds remain in the liquor cycle, self-regenerating to be used again in producing caustic. Sodium metaborate drives autocausticizing reactions in the recovery boiler and forms sodium hydroxide in the smelt-dissolving tank without the use of lime or additional recovery processes, so this technology reduces energy consumption and increases causticizing and calcining capacities. For kraft and soda pulp mills, reducing the lime kiln load not only translates to lower operating costs, energy consumption, and emissions, but also significantly reduces the amount of lime mud that requires special handling and disposal (ITP,2011b).

The concept of borate autocausticizing was first investigated during the early 1980s in Europe. Rio Tinto Minerals developed partial borate autocausticizing (RTM,2010). They obtained support from the US DOE. This technology is being implemented in pulp mills worldwide to supplement conventional lime causticizing with almost no capital investment (ITP,2011b). A full-scale trial of partial autocausticizing with sodium borate was first conducted at Georgia-Pacific Camas mill, Washington State(United States), from 1999 to 2000 for a period of more than 16months (Hunter etal.,2001). In Europe, a full-scale partial borate autocausticizing trial was conducted in 2002 at the Stora Enso Norrsundet mill in Sweden (Bjrk etal.,2005). In this trial, the total lime requirement has been reduced by about 7%, and the autocausticizing level has typically been 911% during the 15-month period. There is some indication that borates may also improve pulp yield (Bjrk etal.,2005). Partial autocausticizing in the P.H. Gladfelter Co. mill in Spring Grove, Pennsylvania, in the United States increased production by about 5% in 2007 (ITP,2011b). However, full borate autocausticizing, which uses borates to drive all the causticizing reactions instead of just lime causticizing, is still undergoing further research and testing (ITP,2006c).

An air jet laden with particles such as that found in primary air issuing from a pulverized fuel pipe for combustion in cement and lime kilns may be synonymous with a jet of fluid with a density greater than that of air provided the particles are small enough that one can consider the fluid to be homogeneous. Under such conditions, the effect of the solid burden may be accounted for by simply assuming an increase in the gas density and a reduction in the kinematic viscosity. A concomitant result will be an accelerated turbulence and an intensification of mixing and the entrainment phenomena associated with it. Equation (3.32) applies in such situations whereby m0 might be increased by the factor 0/a owing to the presence of suspended solid so that the effective change in air entrained per unit volume of jet fluid might increase by a factor of (0/a)2. When the particles are not small enough to behave like a homogeneous fluid, a relative motion occurs between the particles and the surrounding air as a result of gravity or as a result of inertial forces resulting in the damping of the turbulence since the drag between the dust and the air will extract energy from the turbulent fluctuations. One important estimate is the distance at which a particle in a particle-laden jet will travel before coming to rest. This distance is defined as the range , a product of the initial velocity of the particle and the relaxation time R:

The relaxation time is defined here as the time taken for the relative velocity between particle and gas to fall to 36.8% of its initial value. For a perfect spherical particle, the relaxation time is defined as

where m and rp are the mass and radius of the particle, respectively, and is the dynamic viscosity of the surrounding fluid. With these definitions, one can estimate that coal particles with a diameter of 80m injected at 60m/s will have a range of about 150cm, some 150 nozzle diameters for a 1-cm nozzle pipe, and will have little effect on the jet (Field etal., 1967). However, if the particles were finer, for example, 40m in size, then the range would only be 30cm, which would have a damping effect on the jet due to turbulent energy transfer. The relaxation time is a measure of the shortest timescale of turbulence to which the particle could respond. As mentioned earlier, smaller eddies would have rapid velocity fluctuations and the particles would not have time to accelerate to the velocities within the eddies. However, if the eddies are large, then the particles can follow the streamlines without any appreciable slip and the suspension would tend to behave as a homogeneous fluid. It has been shown that increasing the fluid temperature shortens the relaxation time and thereby reduces the size of the eddy to which particles respond. When it falls within the same range as the timescale of the eddies, some damping of the turbulence can be expected, thereby reducing the eddy viscosity (Field etal., 1967). The concomitant result will be a decrease in the rate of entrainment and the rate of spread of the turbulent jet.

The Paraho Development Corporation developed new vertical shaft kiln hardware and process techniques and confirmed new technology in the 1960s by building three large commercial lime kilns. In the 1970s the company adapted their lime kiln technology to oil shale retorting. Paraho obtained a lease from the US Department of the Interior in May 1972 for the use of the US Bureau of Mines oil shale facility at Anvil Points near Rifle, Colorado, to demonstrate their retorting technology. The indirect combustion mode bums process gas in a separate furnace and hot gases carry heat to the retort. This retort can also be operated in a direct combustion (Section 4.16).

In the indirect mode Paraho retort (Fig.14.5), the portion of the vertical retorting chamber that was used for oil shale combustion in the direct mode is now the region of the retort chamber into which externally heated fuel gas is introduced. No combustion occurs within the retorting chamber. That separate combustion process is typically fueled by commercial fuels (natural gas, diesel, propane, etc.) that are often augmented with a portion of the fuel gas recovered from the retorting operation.

In the process, finely-ground oil shale enters a feed hopper on top of the retort after which, in a continuous moving bed, the oil shale flows downward consecutively through the mist formation, retorting, combustion, and cooling zones. As the shale descends, heat is efficiently exchanged with a countercurrent flow of recycle gas, which is introduced into the retort at different levels by three specific-purpose gas-air and gas distributors. Near the top of the retort the ambient temperature shale is warmed by rising hot oil vapors and gas, which, in turn, are cooled to form an oil mist that is entrained in the gas.

While they are very similar in operation, the direct and indirect mode Paraho retorts offer sufficiently different operating conditions so as to change the composition of the recovered crude shale oils and gases. Oil vapors and mists leave the direct mode retort at approximately 60C (140F), while the vapors and gases in the indirect mode leave the retorting vessel at 135C (280F) and have as much as nine times higher heating values than gases and vapors recovered from the direct mode retort (102 and 885 Btu/ft3) oil vapor and mists recovered from the direct mode are diluted with combustion gases from the combustion of the spent shale at the bottom portion of the retort.

The characteristics of the recovered raw shale oil are somewhat different for the direct and indirect mode retorts, but each has characteristics similar to shale oils recovered from other retorts using similar shale heating mechanisms (direct vs. indirect). In addition, gases from the indirect mode retorts have much lower levels of carbon dioxide but generally higher levels of hydrogen sulfide, ammonia, and hydrogen, which are thought to be the result of the indirect mode retort having much less of an oxidizing environment than the direct mode retort (EPA, 1979).

Smelt is cooled and dissolved in water. Hydroxide sodium is regenerated from sodium carbonate reacting with calcium hydroxide in causticisers. The calcium carbonate produced is regenerated in the lime kiln by heating. Regenerated white liquor, containing sodium hydroxide and sodium sulphide, is then sent back to chip cooking.

Low-pressure steam demand for causticising is approximately 20MJ/ adt. Medium pressure (MP) steam demand for lime-kiln oil burners (atomizing steam) is approximately 20MJ/adt. Kiln fuel demand (heavy fuel oil, natural gas or bio-gas produced in a gasification plant using waste wood and bark) is approximately 2.02.8 GJ/adt. Total power demand, including clarifier, filters and the electrostatic precipitator for lime kiln, is approximately 40 kWh/adt.

rotary kiln | top kiln manufacture of rotary kiln, cement kiln and more

rotary kiln | top kiln manufacture of rotary kiln, cement kiln and more

AGICO manufactures all kinds of rotary kiln products for various industries, such as cement production plant, construction, chemicals and metallurgy. The main products include cement kiln, lime rotary kiln and more.

The rotary kiln is always used as a piece of professional machinery for heavy industries. As a chinese leading manufacturer, AGICO not only offers all kinds of rotary kiln and related products, but also provide the complete solution of calcination for various materials.

In order to better satisfy the environmental requirement, AGICO keeps upgrading the rotary kiln system, especially the water treatment, the desulfurization performance of the fuel and the proper treatment of the sulfur content.

We never stop improving the fabrication procedure with evolutionary technology. The enhanced pre-heater and main burner make the whole rotary kiln system use less fuel while maintaining an even better calcination result.

By analyzing the production statistics and improve it constantly, the daily productivity of our new rotary kiln is very close to the machinery from the world-leading players, especially for the lime rotary kiln and large cement rotary kiln.

Our open-type calcination design ensures a free interior airflow, it enables the gas inside the rotary kiln discharge timely. The simple structure also allows the material to move fluidly inside the rotary kiln so that the material can be heated evenly. This further guarantees a stable output.

The new enhanced pre-heater is installed at the kiln tail part. It largely improves the usage of the high-temperature air inside the rotary kiln to increase the efficiency of the pre-heating and decomposition, saving fuel.

Our lime rotary kiln is equipped with an enhanced vertical type cooler. This cooler can cool down the lime faster while increasing the lime activity, which results in easier storage and transportation and less energy consumption.

The temperature of the material inside the rotary kiln is around 1550 while the air temperature is around 1600-1700. The organic matter in the water residual can be cleaned up to 98%. Our rotary kiln has a longer length and a longer retention time for the material.

The waste gas is emitted via a longer channel, fine cooling process and a dust collection system. The content of dust and polluted air is largely reduced. It can meet the regulation requirement for emission. The collected dust can be utilized again by feeding back to the raw material preparation system. The discharged gas from kiln head and tail can be used from waste heat power generation.

AGICO group mainly focuses on major and medium series of rotary kiln products such as cement kiln, lime rotary kiln, shaft kiln, and sponge rotary kiln. Located in Anyang of China, AGICO owns a large heavy industrial factory, it has more than 100 pieces of equipment such as large and medium mental process machines, riveting equipment and assembly equipment with 200 staff and 50 managers and engineers.

What is a rotary kiln? As a piece of key equipment, the rotary kiln plays an increasingly important role in the cement production industry, chemical industry, metallurgy industry and more. The major function of a rotary kiln is to calcinate various materials in a very high temperature environment. During the calcination process, the raw material turns into the desired end products via a series of physical and chemical reactions.

Rotary kiln is not a whole block. It combined with different parts. The main structure contains kiln head, kiln body, kiln tail, support frame, preheating tower, cooler and conveyor. Kiln head consists of an inspection port, coal nozzle, and observation hole. Its diameter is longer than rotary kilns. Kiln body of rotary kiln is the main part of rotary kiln. Its general length is from 30 to 150 meters. It should be laminated refractory brick before running. Kiln tail looks a lot like a lid. It is in the feed end. It is also important which undertakes the ability to feed. Rotary kilns support frame makes kiln more firm. It makes the machine more convenient for lifting and transporting.

temperature measurement and control for cement & lime kilns | process sensors corp - nir and ir measurement

temperature measurement and control for cement & lime kilns | process sensors corp - nir and ir measurement

Hobbyists know a kiln as a small, high-temperature oven used to bake ceramics. But an industrial kiln is a massive oven or furnace known as a rotary kiln designed for the continuous processing of a material.

Rotary kilns are cylindrical furnaces constructed of a steel shell and a refractory lining that rotates along the long axis. The axis of rotation is tilted so that gravity continuously moves a product like limestone from the high end, down the furnace toward a burner at the low end where the product is discharged into the clinker cooler. Rotary kilns are used in a variety of processes, though primarily in the production of lime, dolomite and cement.

Non-contact infrared (IR) pyrometers have been used in cement plants for over forty years. Prior to that, contact thermocouples were the only technology available and required frequent replacement due to mechanical damage or corrosion caused by process gases.

Temperature monitoring at a number of kiln locations is essential to ensure product quality, optimize throughput, minimize emissions, and to prevent damage to the kiln shell and material handling conveyors. Critical monitoring areas are process material preheat, mid-kiln, burning zone, kiln shell and clinker cooler.

To improve efficiency and reduce emissions, exhaust gases from the kiln are used to preheat the rawmix feed material before it entersthe kiln. Inadequate preheating can signal problems in the heat exchanger that will increase fuel consumption costs. Process Sensors Corporation (PSC) 1-color pyrometers can be installed to sight on free-falling preheat material or preheater feed tower wall to alert when temperature falls below a preset level. 2-color sensor models are effective for measuring feed material that is hotter than the vertical tower walls as they can disregard colder temperatures often present in their sight path.

Most modern kilns have a 4 to 5 inch inside diameter by 4 to 5 foot long target tube in the sidewall of the kiln where monitoring mid-kiln temperature is critical to ensure kiln integrity. A PSC Non-Contact Infrared (IR) Pyrometer is recommended for measurement reading during each rotation of the kiln. A variety of fixed focus optics are available where users may choose to integrate laser-aiming light to determine exact alignment to the bottom of the target tube.

The burning zone is the last stage before the material exits the kiln. A single burner fires toward the approaching material, and precise temperature measurement is important to control the firing of the burner. A PSC 2-color pyrometer is effective for monitoring the burner zone as they compensate for dust that can obscure the sight path. Alternatively, a PSC Thermal Imaging Camera is recommended to understand the thermal profile inside of the kiln. Non-Contact Infrared (IR) Pyrometers should not be sighted through the flame, but along the axis or below the flame.

Uneven heating of the kiln shell distorts the metal skin and the cylinder can become banana shaped, damaging the bearings, causing a process shutdown. A PSC thermal imaging camera detects uneven kiln shell heating with real time thermal images so damage and unwanted shutdowns can be avoided. The thermal imaging camera can also be switched into line-scan mode, enabling the customer to easily and quickly replace an old line scanner camera.

Hot process material exiting the kiln (clinker) is conveyed under cooling water sprays. Failure to cool the clinker thoroughly can result in fires at inaccessible locations along the conveyor, or in ball mills. Installation of PSC pyrometers and/or thermal imaging cameras can detect an inadequately cooled clinker to protect against fire.

The PSC-42 Series of simple, 2-wire loop powered sensors offer on-board emissivity adjustment, multiple wavelength options and wide temperature ranges. Ideal for industrial and OEM machine building applications with wide temperature range of -40C to 2500C.

The PSC-40 Series is a two-wired, loop-powered sensor which provides accurate temperature measurement from -40 to 2500C. Also available in fiber optic. Industrial applications including induction heating, steel making, glass, kilns, food, dryers, ovens, furnaces, medical apparatus and R&D.

The Process Sensors Surveyor camera series offers a comprehensive range of imaging and line scanning camera systems to continuously monitor and control industrial processes. Measures temperatures starting from -20 to 1800C

a lime rotary kiln to build your lime calcinating plant

a lime rotary kiln to build your lime calcinating plant

Lime rotary kiln is also called roller rotary kiln. To make sure its air leakage coefficient is less than 10 percent, lime rotary kiln adopts advanced structure and reliable combined scale-like seal in both ends. It also uses composite refractory to reduce the loss of heat radiation.

Lime rotary kilns whole process is well-regulated. The limestone is stored in a silo. Then be carried in preheaters top silo by hoist. There are two-level gauges in silo to control the feed amount. They distribute limestone evenly into different preheaters rooms through feed pipe.

Limestone is decomposed 30% when it is heated to 900 by hot smoke at 1150 . After being pushed into the kiln by a hydraulic push rod, lime is resolved into CaO and CO2. Then be cooled down to 100 by cold air in cooler and then be discharged.

After successively through vibrating feeder, chain bucket conveyor, bucket elevator and tape conveyor, lime eventually is sent into lime finished product library. Then the clients decide whether screening is needed.

Lime rotary kiln has a reliable combined scale-like seal. The scale-like seal in both ends guarantees its air leakage coefficient is less than 10 percent. It also uses composite refractory to reduce the loss of heat radiation.

Lime rotary kiln has a vertical cooler. The filled cooler with dividable ventilation cools down the lime into 80 making it easier to be transported and stored. And it can preheat the secondary kiln air up to more than 700, which reduces the need for moving parts and special materials.

3. Pay attention to the details of the lime rotary kiln below. The gradient of preheater and precalciner should be 3.5%-4%. Precalciners maximum speed should be 3.0-3.5r/min while preheaters should be 2.0-2.5r/min. The speed range should be 1:10.

thermal energy analysis of a lime production process: rotary kiln, preheater and cooler - sciencedirect

thermal energy analysis of a lime production process: rotary kiln, preheater and cooler - sciencedirect

The integrated model for lime production unit which includes cooler, preheater and rotary kiln is developed.The effect of residence time in each section on efficiency is investigated.Influence of material feed rate and excess air on specific fuel consumption is analyzed.The significant effect of particle size on efficiency and specific fuel consumption is shown.

In this paper, thermal energy analysis of three zones of a lime production process, which are preheater, rotary kiln and cooler, is performed. In order to perform a proper quantitative estimation, the system was modeled using energy balance equations including coupled heat transfer and chemical reaction mechanisms. A mathematical model was developed, and consequently, the thermal and chemical behavior of limestone was investigated. The model was verified using empirical data. After model confirmation, the variation of Specific Fuel Consumption (SFC) versus production rate was predicted and the optimum condition was determined. Subsequently, fuel consumption was calculated regarding to altered residence time inside each zone of lime production process, for a constant output. Results indicate that increasing the residence time inside each zone of lime production process, will enhance thermal efficiency and saves fuel consumption. Relative enhancement will be the same for different sizes of limestone. It was found that a 10-min increase in material residence time inside the preheater or rotary kiln can reduce fuel consumption by around two percent. Whereas, a 5-min increase in material residence time inside the cooler would be enough to obtain a similar result. Finally, the ratio of air-to-fuel and production rate are changed in such a way that the same product is achieved. The model predicts that lowering excess air from 15% to 10% leads to a 2.5% reduction of Specific Fuel Consumption (SFC).

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