Progress in the research and development of the ho

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Progress in the research and development of hydrochloric acid regeneration equipment

-- choose Lurgi vulcanization roasting method or lurzna spray roasting method

when recovering the waste hydrochloric acid after pickling, both Lurgi vulcanization roasting method and lurzna spray roasting method can be used. This paper will introduce these two technologies and introduce their new applications in waste gas cleaning

since the 1960s, pickling has become the most commonly used process for steel surface treatment. When recovering the pickling solution containing iron, there are two competing processes: luzna spray roasting method and Lurgi sulfuration roasting method by attracting the required steel ball on the electromagnet. The common point is that it can completely recover the hydrochloric acid and use the regenerated hydrochloric acid for pickling again in a closed cycle. In addition, it also produces iron oxide with great value in iron oxide production, pigment production, ceramic material production and steel treatment. The recovery and regeneration process technology of these two kinds of pickling solutions uses the principle of thermal decomposition, and the difference lies in their production methods and the final products obtained. The powder iron oxide (hematite, Fe2O3) with fine particles is obtained by spray roasting method, and the bulk density is 0.3t/m3. The dense iron oxide obtained by Lurgi sulfuration roasting method has a density of 3.5t/m3

luzna spray roasting method

the hydrochloric acid solution used is sucked out of the special container by the vane pump and the high-pressure pump with the pressure of 0.3~0.5mpa, and sprayed into the heated reactor by the spray gun nozzle. In the reactor, a high-energy torch with oil or natural gas as raw material heats the reactor. The conversion temperature of waste hydrochloric acid in reverse flow mode is 800 ℃. The recovered iron oxide powder is accumulated in the container at the bottom of the reaction tower, or is transferred to the iron oxide powder box by the output worm with the suction device, and is bagged regularly. In the reaction tower, the generated iron oxide powder is separated from the exhaust gas rising to the top of the tower, and the separated iron oxide powder is sent back to the bottom of the tower. The hot exhaust gas is finally cooled in the venturi scrubber, and heat exchange is also carried out to preheat the waste hydrochloric acid solution to be treated. These waste gases containing hydrochloric acid enter the absorber; Another function of the absorber is to load the water required in the production process. In the absorber, the waste gas and hydration synthesize 20% HCl solution, which flows back to the pickling tank. The residual components in HCl gas and the formation of a small amount of Cl2 gas and meticulous oxidation require high rigidity, small deformation under stress, and good stability materials are adopted during manufacturing. Iron powder is quantitatively separated in subsequent fractionators, such as chlorine reaction tower and washing tower

the flow condition of hydrochloric ferric chloride solution in the reaction tower is of great significance for judging whether the chemical conversion process is complete, as well as for the recovery yield of regenerated hydrochloric acid and the complete elimination of chlorine in iron oxide powder. Other details of this process include: the mixing ratio of natural gas and air( λ- Ratio), geometry and size of reaction tower, temperature of combustion chamber and output, packaging and storage of iron oxide powder

spray roasting spray roasting hydrochloric acid recovery equipment can complete the complete regeneration and recovery of pickling hydrochloric acid in addition to the production tasks of fluidized bed equipment. In addition to completing the production task of fluidized bed equipment, hydrochloric acid recovery equipment can also complete the complete regeneration and recovery of pickling hydrochloric acid

The core equipment of Lurgi vulcanization roasting method is a fluidized bed that can produce iron oxide balls with a diameter of 3~5mm and a density of 3.5t/m3. In this fluidized bed, the air sent from bottom to top makes these spherical iron oxide particles suspended in the reactor. The waste hydrochloric acid solution is pumped into the reactor by the transfer pump; The temperature in the reactor is as high as 900~1000 ℃. The iron oxide generated by the reaction is periodically output from the fluidized bed and collected in the iron oxide silo. On the basis of the existing material particles in the reactor, the iron oxide particles gradually grow up and fall under the action of gravity after reaching a certain weight and size

the waste hydrochloric acid solution added to the reactor is heated by using the venturi tube system in a reverse flow manner. Waste hydrochloric acid gas containing HCl is deposited at the bottom of a single-stage washing kettle and forms a regenerated hydrochloric acid solution with HCl viscosity of 20%. This regeneration and recovery process is different from the spray roasting process in recovering hydrochloric acid in a reactor. The HCl free exhaust gas is finally filtered out by the water drop separator under the action of the exhaust fan and then discharged from the chimney

the HCl recovery capacity of conventional hydrochloric acid spray roasting equipment is 2000~25000l/h. The production capacity of the conventional recovery equipment of Lurgi vulcanization roasting method is 2000~9000 L/h; It can reach 11000 l/h under special circumstances. The production capacity of spray roasting equipment is only limited by the volume of the reactor and spray technology; However, Lurgi's Vulcanization roasting law is different. Based on the physical principle of eddy current bed, when the iron oxide particles reach a certain weight, their production capacity is limited by strict certification requirements for each material and component

environmental protection

inorganic hydrochloric acid used in acid pickling process is a substance harmful to the environment. Acid chlorine and fine dust produced in the regeneration and recovery process will be discharged into the atmosphere with the waste gas, causing harm to the surrounding environment. In order to protect the environment more effectively, acege company, an engineering design company specializing in environmental protection, developed a "turnkey project" type waste gas purification equipment, which provides an excellent supplement to the hydrochloric acid recycling process technology. Their two new technology products are: chlorine cleaning equipment and gap tube venturi tube

chlorine cleaning device

manganese contained in steel can form hydrochloric acid containing deposits on the surface of steel after thermochemical reaction with hydrochloric acid as oxidant in hydrochloric acid recovery project, and absorb a small amount of chlorine that can be generated from chlorine containing ferric chloride solution and is harmful to the environment

the cleaning system developed and produced by Andritz company can well complete this dechlorination task. In their SRP process, inert ferric chloride II solution (Eisen (II) chloridl? Sung) for cleaning. Acreg also provides a cleaning equipment for treating acid containing solution in the feeding reaction tower. Compared with other equipment, this spray roasting equipment has three cleaning kettles, which ensures that harmful chlorine will not be discharged to the outside world

gap tube venturi

in the spray roasting equipment for producing large particle iron oxide balls, the dust pollution problem in the old spray roasting equipment is a well-known problem. It is recognized by scientific research institutions that ultrasound can refine slightly suspended dust particles (0.1~1.0 μ m)。 The new product further developed by the gap tube venturi has the following new features: ultrasonic wave is applied to the upper part of the venturi throat. After adopting this technology, the content of iron oxide particles in the gas discharged after cleaning is significantly reduced, whether in the spray roasting waste hydrochloric acid regeneration equipment or in the Lurgi vulcanization roasting equipment. The slotted venturi tube is integrated with the gas cleaning equipment, which can be installed either in the last reactor or in the exhaust chimney. (end)

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