Congratulations  to“ the technology of central burner lime kiln” entering into China. Home Cleaner Production Advanced Technology Catalogue

 On  November 28,2022, the Ministry of Ecological Environment issued a report on the "National." Home cleaner production advanced technology catalogue (2022)"(publicity draft) publicity.

 Among  them, the 14th“ central burner energy-saving environmental protection gas burning active lime kiln”is the only one selected this time. A clean production advanced technology involving lime production, this technology is the key core technology with industrial pilot significance and broad application prospects for the development of domestic lime industry at present. Home to its contribution to the dual carbon target in the industry. High offer. certainty and expectation.

 This  Catalogue introduces in detail the technical content, process route, scope of application, energy saving effect, water saving effect, material saving effect, pollution reduction effect, carbon reduction effect and technical characteristics of this technology. For detailed technical implementation and technical upgrading, please refer to the Company News on the homepage of this website for a complete set of materials. For details of this technology, please refer to Item 14 in the Annex.

  Brief Introduction of TMS Technology in Tangshan Jinquan Company

 Tangshan  Jinquan Company independently developed the“ seventh generation lime shaft furnace with built-in circulating combustion” and“ central burner composite fuel lime shaft furnace technology, which” is another improvement and innovation in the traditional“ central burner gas-fired lime kiln” technology, and has obtained two invention patent rights and three utility model patents. This series of technologies effectively improves resource and energy efficiency by deeply integrating green clean energy utilization with lime production energy saving and emission reduction. The seventh generation technology is to expand the selection limitation of the former six generations of technology that can only use low calorific value industrial tail gas for single fuel production to a compound fuel structure that can use natural gas + biomass gas + coal + biomass powder injection, so that the fuel used in furnace production is more extensive, the cost is lower, and the operation is simpler and more practical. This technology fully utilizes industrial waste heat, low grade waste heat and other heat sources in the lime production process, a furnace internal heat energy recycling device and an external integrated heat energy conversion device, stores and recycles all residual heat or unstable heat energy through heat transfer working medium, realizes the waste heat exchange application of the cooling zone and preheating zone of the lime kiln, solves the problem that the heat energy supply and demand of the furnace body roasting system are not matched in time, space or intensity, The aim of coupling conversion between different energy sources and continuous utilization of clean energy can be achieved, and the goal of deep energy saving and efficiency improvement can be achieved. At present, with the continuous improvement and upgrading of technology, various technical indicators are becoming more and more perfect, and have reached the international advanced level, which can greatly enhance the carbon reduction competitiveness of lime production enterprises. Home dual carbon goal made Zhuo. Vietnam pays tribute. Offer.

  Atpresent, this technology adopts biomass gas or natural gas and coal (mixed combustion) as the main line of the process, which can be produced by gas alone or by coal mixed combustion alone. If the gas source is insufficient or the heat is insufficient, it can also supplement part of coal production. By setting multi-stage blowing device in the central area of furnace, this technology can gradually apply the production mode of blowing biomass powder.

   Thecore point of this technology is the ingenious design and application of a self-circulating central flame burner in the furnace. The waste heat of flue gas in the preheating section is directly mixed with the burner in the furnace, which can provide a strong central flame temperature for the center of the calcination zone. It solves the key problems such as serious burning of central stone caused by short flame, low flame temperature and uneven temperature distribution of calcination section, improves the output and quality, realizes the development of large scale calcination of lime with low calorific value gas fuel and the feasibility of compound application of multiple fuels.

 in  ord to achieve that purpose of energy saving, a multistage circulation device is design and applied in the preheating zone of the furnace type, so that the gas flow in the furnace is self-circulated, the central air supply channel of the furnace is opened, and the positive pressure production is changed into negative pressure production, so that the air supply and the ignition of the material surface in the furnace can be more uniform, and the problems of“” high lime overburn rate, furnace wall agglomeration, suspended material, collapsed material and the like caused by the kiln wall effect and the central funnel effect caused by the air supply at the bottom of an ordinary lime shaft kiln are solved; and the problems of environmental protection treatment can be effectively solved due to the adoption of negative pressure production, and carbon dioxide gas in the furnace can be forcibly decomposed and exhausted rapidly, so that the air distribution, oxygen supply, pressure and combustion in the furnace tend to be more reasonable, and the lime overburn rate can be effectively reduced and the lime activity can be improved. At the same time, because the waste heat energy of flue gas in the furnace is fully recycled in the preheating zone and the burner in the furnace, the materials in the preheating zone can fully absorb heat to achieve energy storage, and the fuel energy consumption can be further reduced.

 At  present, the production index of this technology tends to be in the leading position in the lime production process of shaft furnace. Under the production conditions of qualified stone, the overburning rate of lime can be stabilized at 3-7%, and the calcium oxide content can be stabilized at 88-94%. Lime activity is stable in the range of 320-390ml.

  Atthe same time, aiming at the users of high activity industrial lime products, this technology is designed and applied to the technology of producing active lime by hydrogenation method and gasification method in furnace (invention patent) of * new Tangshan Jinquan Company, and the lime activity can be stabilized in the range of 340-430ml.

   The“ seventh generation technology” has been officially promoted in 2022, and the first five“ provincial demonstration projects” will be put into production for six consecutive years at the end of this year, and some projects have been completed a few days ago. This series of technology has obtained the industry promotion certificate and has been officially named TMS type central burner lime shaft furnace.

 Introduction of Technology and Equipment of TMS Type Lime Shaft Furnace with Central Burner in Tangshan Jinquan Company

1)Feed preheating and batching system:

 Raw materials and mixing system to achieve intensive combination design process, screening, cleaning, weighing, mixing of raw materials more simple, practical, reduce the occupied area.

 Special design and selection of raw material preheating system, can reduce or eliminate easy to powder difficult to bake limestone burst.

2) Winch feeding system:

 The inclined bridge truss double-track double-car cycle feeding and frequency conversion speed regulation are adopted, which can save more than 30% of electricity compared with the single-car feeding mode.

3) Roof system:

 A new generation of multi-stage composite screening tilting rotary distributor complete set device is selected, which can realize the integration of screening, lifting, rotation, tilting and distribution of materials in the furnace. The main innovation point of the device is that it can carry out composite classification screening and fixed-point distribution of stones with different particle sizes in the furnace through multi-stage composite rotating screening and tilting distribution device, and can distribute stones differently according to different particle sizes according to the circumferential radius of the furnace body.

4) Air supply and distribution system:

 The air supply policy of selecting the new seventh generation equi-circular cone probability hood device is as follows: high oxygen enrichment, stable air pressure, uniform air volume, low power and large effect, which makes the air flow distribution on the unified section of the kiln body tend to be consistent, effectively solves the kiln wall effect and the core pulling problem of the material column, realizes quantitative air supply, can make the air supply on the section of the material surface in the furnace uniform, the air flow distribution is more uniform, effectively reduces the segregation of the air flow in the seepage zone in the furnace, and opens up the air flow distribution in the one-dimensional seepage zone, the two-dimensional seepage zone and the three-dimensional seepage zone to realize the oxygen-enriched combustion effect.

5) Ash extraction system:

 Multi-channel and multi-point stable feeding can be realized by selecting a complete set of multi-channel rotary ash extractor. Multi-point rotary metering ash extractor is installed in the ash extraction system of lime shaft furnace body, so that the furnace condition can be controlled and adjusted by accurately controlling the ash extraction amount during production. It can realize graded multi-point discharge, quickly and effectively solve the phenomenon of uneven and partial feeding, and can quickly solve the phenomenon of partial burning and partial feeding in the kiln at fixed points and multi-point discharge, and the material column resistance is uniform and the discharge is smooth. The device realizes multi-channel synchronous rotary ash discharging, a plurality of adjustable discharging device discharging points distributed on the periphery of the furnace are collected into a rotating mechanism, and synchronously rotate and discharge with a rotating body, and the ash discharging amount of each ash discharging device is adjustable; and the accumulation sequence of finished lime before falling is changed by adjusting and controlling the rotating speed and the discharging speed of the rotating body, so that the charging at all parts of the cross section in the furnace is uniform, the ash discharging is accurate, the ash discharging efficiency is high, the finished ash is not broken, and the material level in the furnace is lowered and leveled.

6) Ash unloading system:

 A new type of two-stage ash discharge valve device is selected in the design. The ash discharge device is the key part affecting the utilization coefficient and operation of the furnace. The newly developed two-stage ash discharge machine of Tangshan Jinquan Company can discharge ash normally without stopping wind, effectively avoiding the leakage of furnace gas. Therefore, stable and constant air supply and reasonable distribution of air flow in the furnace are realized, the calcination quality is ensured and the working environment is improved.

 7) Furnace body: new type simulation furnace selection:

 The main feature of this technology is the selection of modeling furnace type. This furnace type synthesizes some advantages of conical vertical kiln, vase vertical kiln and straight vertical kiln. The inner cavity of kiln type adopts AHA modeling structure. The combination of multi-cone platform and linear structure changes the mode of upper and lower cone closing of kiln body. Through the shape combination of new air cap and furnace wall of cooling zone of kiln body, the straight direction of air flow in cooling zone is changed. The air flow radiates to the central area of calcining zone, which increases the air flow rate flowing to the center of calcining zone by more than 30%, and reduces the air flow rate of the same flow around the kiln wall of calcining zone. The airflow flowing from calcination zone to preheating zone also changes into zigzag flow direction, so that the flow rate of high temperature hot airflow gradually increases to the center of preheating zone, and the ventilation effect of the center of preheating zone is strengthened. This technology realizes the three-stage oxygen-enriched dynamic calcination mode of lime shaft kiln.

8) Combustion air and cooling air system

 Combustion-supporting air and cooling air system mainly consists of Roitz fan, muffler, filter, safety valve, pressure gauge, manual hoist and air supply pipeline.

9) Furnace body baking system:

 The combustion system of calcinations zone of furnace body adopts the mode of combined application of peripheral burner outside furnace and central combustion device inside furnace. The burner outside the furnace has stable and reliable combustion, long service life without tempering, and strong flame penetration ability. By adopting multi-stage composite combination mode, through the control of high speed, sub-high speed, normal pressure and other pressures and flow rates, the burner flame can achieve complementary combustion of long flame and short flame in different regions, so that the combustion atmosphere in the furnace is more sufficient.

   The combustion power of the new type central combustion device in the furnace reaches 15~28GJ/h. A strong central flame is provided for the center of the roasting zone, so that the heat energy supply in the center of the furnace is more balanced, and the problems of low output and high lime burning rate caused by the fact that the heat energy can not reach the center of the furnace when the inner diameter of the traditional peripheral burner type gas shaft kiln is too large are solved. Compared with the traditional peripheral burner lime kiln diameter can not be greater than 3m, the center burner lime kiln diameter can now exceed 6m, it can be seen that the improvement of the center burner technology is the most critical place in this technology.

10) Vaporization activity regulating device:

   With brand-new production technology and concept, shaft kiln structure utilizes new combined production technology, and uses water as main medium to produce active lime by physical steam method. The activity and purity of lime are improved by adding additive and adopting gasification method and activation method. Through steam bath and heating medium, the temperature in the kiln can be equalized, the raw burning and overburning can be reduced, the decomposition speed of CaCO3 can be accelerated, and the calcination time can be reduced, so that the productivity can be improved and the energy consumption can be reduced. The production process realizes clean production, the lime S content is low, and the obtained calcium oxide has high purity.

 This technology is simple, low cost, lime activity can be stable in 330-420ml, the maximum is more than 440ml, it is a new generation of technology for shaft kiln production of active lime.

11) Electric control system:

 Electric control system includes power supply, electric control automation, lighting design and lightning protection grounding design. Siemens S7 - 300 PLC system is adopted for automatic control system, WinCC system is adopted for man-machine operation interface; electric control technology: automatic control is adopted for feeding system equipment, manual field operation is cancelled, fans and various electric valves are adopted, main control and machine side control are adopted, and main control and machine side control are adopted for ash unloading and crushing system equipment. Temperature, pressure, flow detection remote display in the main control room.

12) Innovative application of ultra-low emission environmental treatment technology (optional):

 12.1. Dust removal and desulfurization system for roof discharge (proprietary technology)

 It is mainly composed of four separate flue gas pipeline emission dust removal and desulfurization devices, which are used for flue gas purification when flue gas is emitted from the furnace top under abnormal furnace conditions, and also can be used as an essential device for temporary production when the ground dust remover is overhauled or shut down.

 12.2. Dust emission control:

 By selecting new bag filter and adding rotary first stage dust collector and air cooling device, the flue gas temperature can be controlled and adjusted, and the dust purification emission index can reach the range of 10mg/m ³.

 12.3. Flue gas double removal treatment system:

 The system can realize simultaneous desulfurization and dewhitening of flue gas from the top of the furnace, and can realize simultaneous removal of SO2 and dewhitening in flue gas in one process, and finally realize the integrated mode of double dewhitening. The desulfurization purification emission index can be achieved: 50-100mg/m ³ range.

 12.4. Application of Embedded Cascade Furnace Reduction and Denitrification Technology (TLH):

  The technical principle comes from SNCR denitration technology principle, SNCR is selective non-catalytic reduction (Selective Non-Catalytic Reduction) is a mature low-cost denitration technology. The key point of this technology is that no catalyst is needed, only the reductant reacts with NOx in the high temperature flue gas to generate nitrogen and water, while the oxygen in the flue gas rarely reacts with the reductant, thus achieving the effect of selective reduction of NOx.

12.5, * New denitration free production process

  When blast furnace gas and biomass are used, under the same raw fuel conditions, the total exhaust gas volume per ton of ash and the oxygen content of exhaust gas are greatly reduced, and the oxygen content of exhaust gas at the top of the furnace is only 2%~5%, completely avoiding the trouble of conversion of oxygen content of emissions. Moreover, since the industrial tail gas and clean fuel with very low sulfur content are mainly used, the sulfur content is very small, and the ultra-low emission standard can be achieved without investing in the construction of desulfurization equipment, and the operation cost of desulfurization is also saved. At the same time, because the limit furnace temperature of calcination zone is 1250℃, and the high temperature zone is short, the oxygen concentration is low, and the waste heat of multi-stage circulation of kiln top exhaust gas is utilized, the thermodynamic conditions for generating thermodynamic NOX are effectively eliminated, so there is no need to invest in the construction of denitration equipment, the ultra-low emission standard can be achieved, and the operation cost of denitration is saved.

 Issue Date: February 22, 2023