ZGS Double-chamber Lime Kiln with External Channel Support for Mixing and Injection
I. The eighth generation ZGS external support type biomass gas-fired lime kiln technology invention technical characteristics:
 1 . The eighth generation ZGS external support type biomass gas-fired lime kiln can realize the conversion of production function between single chamber vertical kiln and double chamber vertical kiln. Through measures such as external circulating flue, external flue inclined support structure, detachable spray gun device, extended furnace body structure, flue control valve, automatic flue kiln dust cleaning pneumatic conveying device, multi-point rotary weighing ash discharge system, kiln top waste heat drying and screening, suspended calcined powder, etc., The invention not only achieves the purpose of independent use of lump solid fuel for mixed production, but also realizes the purpose of producing high-activity lime by dual-chamber heat storage and injection of powdery fuel such as coal, biomass and other fuels and gas fuels such as industrial tail gas, biomass gas and natural gas, and realizes the purpose of suspending and calcining powdery lime by waste heat. At the same time, it also solves the key problems such as structural defects, production defects and safety hazards caused by the traditional double-chamber kiln with corbel support and suspension cylinder structure.
 2. The technology is simple, practical and compact in structure, high in production efficiency, high in yield and good in economy. in particular, that application of technology such as transformation and upgrading of traditional single-chamber mix lime shaft kilns and suspension calcination of powder have important significance in improving the overall lime production technology level, reduce production costs, improving product quality, reducing pollution and carbon, improving ecological environment and the like. This technology is an important innovation and technical upgrading of traditional lime kiln structure and lime production mode.
 3. The technology uses the combination of clean fuels such as natural gas and biomass gas to achieve the dual purpose of reducing carbon and reducing carbon social benefits and improving quality and efficiency. When using biomass gas fuel alone, it can reduce fuel costs by more than 40% compared with coal. Moreover, it has deep utilization of biofuels, reduces serious pollution caused by the use of fossil fuels, improves the overall lime production process level, reduces production costs, improves product quality, and has important significance in reducing pollution and carbon, improving ecological environment, and ensuring national energy security. In terms of environmental benefits, the emission index after combustion of biomass gas is close to that after combustion of natural gas, and the innovative application of biomass energy technology will effectively promote the clean development and sustainable development of enterprises.
II. The eighth generation ZGS external support type biomass gas-fired lime kiln process and equipment introduction:
1. Key process measures adopted:
(1) The eighth generation ZGS external support type biomass gas-fired lime kiln adopts a new type of waste heat flue gas circulation channel outside the kiln, which makes the kiln body structure more reasonable and safer.
(2), the use of a new type of kiln flue inclined support, so that the kiln combustion and flue gas circulation uniform distribution, no dead angle.
(3) Convenient detachable spray gun is adopted to facilitate process adjustment when different fuel structures are adopted.
(4), in the kiln cooling zone with extended furnace structure, from the bottom of the kiln body calcination zone gradually expand the diameter of the kiln body, so that the calcination zone and cooling zone waste heat flue gas flow direction is more reasonable, and the cooling zone of the material cooling time is more sufficient, lime activity is higher.
(5) Set flue control valve inside flue between two kilns to realize the opening and closing of waste heat flue gas between two kilns, so as to achieve the independent production function of single-chamber kiln when using mixed material production and the heat storage function of flue gas communication between two kilns when using double-chamber regenerative production.
(6). Several ash removal devices are arranged at the lower part of the flue gas circulation channel outside the kiln body, and the pneumatic conveying mode is adopted to realize the ash transportation, which solves the problem that the traditional double-chamber kiln needs empty air. gases. High pressure ash removal and periodic shutdown of manual ash removal defects.
(7), the use of multi-point rotary weighing ash system and other measures, to achieve multi-point unloading and material weighing, to achieve different production processes in different ash amount adjustment, weighing.
(8), set up kiln top screening and flue gas pressure equalization drying process, realize the stone in the kiln top automatic secondary screening, drying and preheating with part of the flue gas circulation channel, not only to achieve the purpose of flue gas pressure equalization, but also to make the screening effect more obvious.
(9) In the present invention, a fine stone powder crushing device is installed at the top of the furnace to crush the stone powder screened at the top of the kiln to less than 1mm, and suspend heat exchange calcination with flue gas exhaust gas to directly convert the powder into lime powder (calcium oxide powder), so as to achieve the purpose of energy saving and waste heat utilization.
(10). In the present invention, the waste heat and waste gas released after the dust deposition is pneumatically conveyed by the dust deposition removal device at the lower part of the flue gas circulation channel outside the kiln body is heated again at a constant temperature by electromagnetic induction, so that the temperature of the waste gas reaches the decomposition temperature of lime powder during suspension combustion.
2. Key equipment and measures adopted:
(1) Independent annular flue gas channels are arranged outside the kiln shell at the lower part of the calcination zone of the kiln body, the outer shell of the annular channel is connected with the furnace shell by steel, the inner part is built with refractory materials, and the annular flue gas channels between the two kiln bodies are interconnected.
(2) The annular flue gas channel of the kiln body is communicated with the flue gas in the kiln by several independent inclined flue type support structures. The shell of the support structure is connected with the annular flue gas channel and the kiln shell by steel structure. The refractory material is built inside. The interior of each inclined flue type support structure is hollow.
(3) The preheating zone and calcination zone of kiln shell adopt straight tube structure, and the internal masonry refractory material is used to meet the process requirements of mixing lime production.
(4) The cooling zone of kiln shell adopts extended right cone steel structure, and refractory materials are built inside to meet the technological requirements of double-chamber kiln body production.
(5) Set heat-resistant control valve at tangent position between annular flue gas channel of two kiln bodies. When double-chamber kiln body is used for production, open valve to realize flue gas communication between two kiln chambers and adjust flue gas flow rate. When mixed production is used, close valve to block flue gas communication between two kiln chambers and realize single-chamber mixed production.
(6) Ash bin shall be set between every two inclined flue type support structures at the lower part of flue gas annular channel, refractory materials shall be built or poured inside ash bin, and valve or feeding device shall be set at the lower outlet of ash bin to connect with annular pneumatic conveying pipeline.
(7), in the ash system set up multi-point rotary weighing ash system and other measures, through the rotating mechanism to transport materials to the weighing device inside, in order to accurately control the amount of ash and adjust the furnace condition.
(8) Set a convenient detachable spray gun in the preheating zone of the furnace body, and the outlet of the spray gun is set at the joint of the bottom of the preheating zone and the upper part of the calcining zone, so as to realize the purpose of injecting solid powder fuel and gas fuel during the production of the double-chamber kiln. The spray gun structure is detachable, and the spray gun can be disassembled conveniently when mixed production is adopted.
(9) Fixed screening and preheating drying device is set inside the kiln top buffer bin to screen the stone for the second time, and the powder under the screening directly enters the compound crusher for fine crushing.
(10), in the lower part of the compound crusher set up a single cylinder spinning suspension preheater for primary preheating decomposition, so that the decomposition temperature of lime powder to 300℃ above.
(11). Double cylinder spinning suspension preheater is set under single cylinder spinning suspension preheater to carry out secondary preheating decomposition, so that the decomposition temperature of lime powder can reach 800℃ above.
(12) Set a constant temperature calcination reaction kettle at the lower part of the double-cylinder spinning suspension preheater to perform constant temperature flash calcination on lime powder with exhaust gas from the waste gas circulation channel of lime kiln body at about 600-700℃, and decompose lime powder into active lime within 1 second.
(13) Set electromagnetic induction heating temperature regulating device on the exhaust gas outlet pipeline of powder release bin to heat the released exhaust gas to 1100℃ and transport it to the inside of constant temperature calcination reactor to increase the temperature, so as to achieve the purpose of constant temperature flash calcination. The electromagnetic induction heating temperature adjusting device has the function of adjusting temperature, so that the temperature of the constant temperature calcination reaction kettle can be adjusted and kept in a temperature range.
III. Innovative application of“ ultra-low emission” environmental treatment technology:
1. Dust removal and desulfurization system for roof emission (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.
2. Dust emission control:
 A new type of bag filter is selected and a screw-down primary dust removal and air cooling device are added to achieve controllable and adjustable flue gas temperature, which can achieve the dust purification and emission index: 10-25mg/m ³ range.
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.
4. “Application” of 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.
 This  technology has been subjected to long-term experimental research, numerical calculation and engineering practice. The technical system has the following significant advantages:
(1), without adding denitration tower, reactor and other large-scale investment equipment outside the furnace, to achieve direct denitration in the lime kiln, in the lime kiln body suitable temperature zone embedded installation of denitration equipment, does not affect the normal production operation of the lime kiln, and can be arbitrarily adjusted or stopped the operation of denitration equipment. Because denitration is carried out in different temperature areas in the furnace, waste heat in lime kiln production is fully utilized, and energy consumption increased by external temperature increase is not required.
(2), do not use ammonia and other materials as reducing agents, using new polymer materials readily available everywhere as reducing agents, denitration effect is better, no water and gas secondary emission pollution and no solid waste generation.
(3), using gas phase method and liquid phase method comprehensive operation method, the lime kiln production in the motive power system to transport the medium to the furnace, activation and vaporization in the furnace, instantaneous chemical reaction with NOx, reduced to N2 and H2O.
(4), the use of cascade treatment method, clever use of the lime calcination process when the stone falls and the airflow generated by the reverse exchange of sufficient airflow residence time for NOx reduction reaction, can be in the NOx generation source combustion process control to reduce NOx content, and temperature selectivity is also strong, making the operation simpler.
(5) The reducing atmosphere in the furnace is uniform, the pressure is stable, the resistance is small, and the denitration reduction zone is set in the oxygen-lean and fuel-rich area, which helps to reduce the nitrogen in the fuel to form NOx(i.e. fuel-type NOx).
(6) To achieve automatic control, an independent programmable logic controller is used to control and adjust the operation of major equipment based on relevant collected signals to achieve efficient denitrification.
(7), the system equipment structure is simple, the equipment occupies a small area, can be installed in the lime kiln free place platform.
(8), investment is extremely low, cost-effective, and selective catalytic reduction (SCR) technology investment compared to only 10% of its investment, very cost-effective investment, especially suitable for private enterprises to choose applications.
(9) The operating cost is extremely low, and the operating cost is about 2-4 yuan/ton lime, which is about 200% to 300% lower than that of selective catalytic reduction (SCR) technology.
(10), high denitration efficiency: 75-90%
5.* A New Denitrification 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.