阅读说明：本技术 一种清洁高效的亚硫酸法蔗汁澄清方法 (Clean and efficient method for clarifying sugarcane juice by sulfurous method ) 是由 罗荣宁 蓝胜宇 黄永春 于 2019-09-27 设计创作，主要内容包括：本发明涉及一种清洁高效的亚硫酸法蔗汁澄清方法,该方法是混合汁经过预灰、一次加热后,进入硫熏中和反应器中进行硫熏中和反应,硫熏中和反应器出来的气液混合物通入散气箱,将散气箱出来的尾气通入吸收装置,吸收装置中同时从石灰乳贮箱中导入石灰乳溶液对尾气中的SO<Sub>2</Sub>进行吸收,然后将吸收了SO<Sub>2</Sub>的石灰乳溶液导流回到石灰乳贮箱,石灰乳贮箱同时向硫熏中和反应器通入石灰乳溶液,散气箱出来的硫熏中和汁按常规进入二次加热和沉降工序。该方法使SO<Sub>3</Sub><Sup>2-</Sup>和Ca<Sup>2+</Sup>能够快速、充分反应析出CaSO<Sub>3</Sub>沉淀,从而降低澄清汁中残留的SO<Sub>3</Sub><Sup>2-</Sup>和Ca<Sup>2+</Sup>,降低成品白砂糖的残留硫含量,同时提高蔗汁对SO<Sub>2</Sub>的吸收率,尾气中SO<Sub>2</Sub>含量,降低硫磺用量,有效保护环境。(The invention relates to a clean and efficient clarification method of cane juice by sulfurous method, which comprises the steps of pre-ashing mixed juice, heating the mixed juice for the first time, then putting the mixed juice into a sulfitation neutralization reactor for sulfitation neutralization reaction, introducing a gas-liquid mixture from the sulfitation neutralization reactor into a gas dispersion box, introducing tail gas from the gas dispersion box into an absorption device, and simultaneously introducing a lime milk solution from a lime milk storage box into the absorption device to clarify SO in the tail gas 2 Absorbing, and absorbing SO 2 The lime milk solution is guided back to the lime milk storage tank, the lime milk storage tank simultaneously feeds the lime milk solution into the stoving neutralization reactor, and the stoving neutralization juice from the gas dispersion tank enters the secondary heating and settling procedure according to the conventional method. The method makes SO 3 2‑ And Ca 2+ Can quickly and fully react to separate out CaSO 3 Precipitation, thereby reducing clarificationResidual SO in the clear juice 3 2‑ And Ca 2+ Reduce the residual sulfur content of the finished white granulated sugar and simultaneously improve the SO content of the cane juice 2 Absorption rate of (3), SO in the exhaust gas 2 The content is reduced, the sulfur consumption is reduced, and the environment is effectively protected.)

1. A clean and efficient clarification method of sulfurous sugarcane juice is characterized by comprising the following steps: pre-ashing and primary heating the mixed juice, then putting the mixed juice into a sulfitation neutralization reactor for sulfitation neutralization reaction, introducing a gas-liquid mixture discharged from the sulfitation neutralization reactor into a gas dispersion box, introducing tail gas discharged from the gas dispersion box into an absorption device, and introducing lime milk solution into the absorption device to remove SO in the tail gas₂Absorbing, and absorbing SO₂The lime milk solution is guided back to the lime milk storage tank, the lime milk storage tank simultaneously feeds the lime milk solution into the stoving neutralization reactor, and the stoving neutralization juice from the gas dispersion tank enters the secondary heating and settling procedure according to the conventional method.

2. A clean and efficient sulfitation cane juice clarification method according to claim 1, characterized by: and (3) introducing a lime milk solution and tail gas into the absorption device in a volume ratio of (1: 100) to (1: 10).

3. A clean and efficient sulfitation cane juice clarification method according to claim 1 or 2, characterized by: and introducing lime milk solution into the absorption device from the lime milk storage tank.

4. A clean and efficient sulfitation cane juice clarification method according to claim 1 or 2, characterized by: the absorption device is a spray type absorption tower or a tower plate type absorption tower.

Technical Field

The invention belongs to the field of cane juice or sugar liquor clarification in a sugar making process, and particularly relates to a clean and efficient method for clarifying cane juice by a sulfurous method.

Background

The clarification of cane juice (sugar juice) is a key link in the sugar manufacturing process, and the clarification effect of cane juice (sugar juice) is related to the product quality, the sugar recovery rate and the dosage of a clarifying agent, so that the competitiveness of a sugar refinery is influenced finally. The existing sulfurous method clarification process commonly adopted by sugar refinery adds SO₂Lime milk and phosphoric acid, forming calcium sulfite precipitate and calcium phosphate precipitate to adsorb and remove colloid and pigment in the sugar juice, SO₂And Ca (OH)₂The neutralization reaction speed and degree in cane juice (sugar juice) will directly affect the clarification and decolorization effects of the mixed juice and the SO in the clear juice₃ ^2－And Ca^2＋The residual quantity of the white granulated sugar can further influence the indexes of the occurrence degree of post reaction, the settling velocity, the purity of clear juice and the like in the subsequent precipitation or floating process, the heat transfer efficiency, the scale deposition condition and the like of evaporation equipment, and finally influence the indexes of the color value, the sulfur content, the ash content, the energy consumption and the like of a sugar factory of finished white granulated sugar.

The main process of the sulfur clarification process by the sulfurous acid method at present is to carry out sulfitation neutralization on heated mixed juice, and then the neutralized juice is settled or floated after being heated. The stoving neutralization reaction is generally completed by a vertical or horizontal pipeline cane juice stoving neutralizer through spraying and pumping. The stoving neutralizer has the following main defects: (1) cane juice absorbs SO₂Slow and insufficient speed; (2) lime and SO₂The reaction is not complete enough; (3) the granularity of the calcium sulfite precipitate is uneven, and the adsorption capacity is lower. Therefore, the following problems often occur during production and use: (1) the subsequent process has larger pH fluctuation of the cane juice, which affects the quality of the cane juice; (2) SO in clear juice₂The residual quantity is large, and finally, the sulfur content in the finished white granulated sugar is high, so that the white granulated sugar is degraded; (3) high residual calcium salt content in sugar juice, resulting inThe ash content of the product is high, and the fouling of equipment pipelines is serious; (4) the sugar juice has high content of inorganic substances, so that the honey production rate is increased, and the sugar recovery rate is reduced; (5) due to CaSO₃The particles are not firm and uniform, the adsorption and sedimentation performance is reduced, and the decoloring effect is poor; (6) lime and SO₂Incomplete reaction, SO₂Cannot be fully absorbed and utilized, and has large sulfur consumption; (7) since cane juice absorbs SO₂Insufficient SO in the exhaust gases from the blow-down boxes₂The content is high, and the environment pollution can be caused by directly discharging the waste gas into the atmosphere.

Chinese patent CN200910308507.2 discloses a cane juice clarifying process method for enhancing sulfitation, which comprises the step of introducing tail gas from a primary gas diffusion box into a secondary sulfitation neutralization reactor for sulfitation neutralization reaction, namely utilizing SO₂The tail gas is subjected to a second stoving neutralization reaction, SO that SO in the tail gas is reduced to a certain extent₂And (5) pollution to the environment. But SO in this patent₂The use of tail gas cannot accelerate SO₃ ^2-And Ca²⁺The reaction of (2) does not greatly contribute to the improvement of the cane juice clarification effect.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: provides a method for strengthening SO in cane juice₃ ^2-And Ca²⁺A clean and efficient sulfurous cane juice clarification method for reaction, which ensures SO₃ ^2-And Ca²⁺Can quickly and fully react to separate out CaSO₃Precipitating to reduce residual SO in the clarified juice₃ ^2-And Ca²⁺Reduce the residual sulfur content of the finished white granulated sugar and simultaneously improve the SO content of the cane juice₂Absorption rate of (3), SO in the exhaust gas₂The content is reduced, the sulfur consumption is reduced, and the environment is effectively protected.

The technical scheme for solving the technical problems is as follows: a clean and efficient clarification method of sulfurous sugarcane juice comprises the steps of pre-ashing mixed juice, heating the mixed juice for the first time, enabling the mixed juice to enter a sulfitation neutralization reactor for sulfitation neutralization reaction, introducing a gas-liquid mixture discharged from the sulfitation neutralization reactor into an air dispersing box, introducing tail gas discharged from the air dispersing box into an absorption device, and introducing a lime milk solution into the absorption device to clarify S in the tail gasO₂Absorbing, and absorbing SO₂The lime milk solution is guided back to the lime milk storage tank, the lime milk storage tank simultaneously feeds the lime milk solution into the stoving neutralization reactor, and the stoving neutralization juice from the gas dispersion tank enters the secondary heating and settling procedure according to the conventional method.

And (3) introducing a lime milk solution and tail gas into the absorption device in a volume ratio of (1: 100) to (1: 10).

And introducing lime milk solution into the absorption device from the lime milk storage tank.

The absorption device is a spray type absorption tower or a tower plate type absorption tower.

The invention is mainly characterized in that: (1) by using SO in the exhaust gas₂Reacting with partial lime milk, returning to lime milk box, introducing into sulfur fumigation neutralization reactor for sulfur fumigation neutralization of cane juice, and fully utilizing pre-formed fine CaSO₃The precipitated particles are used as crystal nuclei in the cane juice sulfitation neutralization reaction, SO that SO in the sulfitation neutralization reaction₃ ^2-And Ca²⁺The reaction is more sufficient and rapid, and the SO in the neutralization juice is greatly reduced₃ ^2-And Ca²⁺And the adsorptive clarification performance of the precipitated particles is increased; (2) absorbing device for SO in tail gas₂Absorbing SO in tail gas₂The concentration is reduced to below 20PPm from 200-2000PPm in the normal condition, and SO in the tail gas is reduced₂The pollution to the environment is reduced, and the consumption of sulfur is effectively reduced.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

(1) residual SO in cane juice₃ ^2-、Ca²⁺The content is low.

SO in cane juice obtained by settling and clarifying after sulfitation neutralization₃ ^2-、Ca²⁺The content of (A) directly influences the content of sulfur dioxide in the white granulated sugar and the ash content of the product. With the development of national economy and the improvement of product quality consciousness, the requirement of the sulfur dioxide content of the white granulated sugar is on the trend of further reducing; and residual Ca in sugar juice²⁺High content of the components can lead to high ash content of the product and reduction of the ash contentThe product quality, and the content of inorganic substances in the sugar juice are high, which can increase the honey production rate and reduce the sugar recovery rate, and on the other hand, the residual Ca in the sugar juice²⁺Inorganic salts can cause serious scale deposition of equipment pipelines, reduce heat transfer efficiency, increase energy consumption and reduce production efficiency. The invention is implemented by leading lime milk to have a part of Ca (OH) before entering a stoving neutralization reactor₂And SO in the tail gas₂Reaction due to SO₂Low concentration, formation of fine CaSO₃Precipitating particles which become SO during the sulphitation neutralization of cane juice₃ ^2-And Ca²⁺CaSO formed by the reaction₃Crystal nuclei of precipitation of SO₃ ^2-And Ca²⁺The reaction is more sufficient and rapid, and the SO in the neutralization juice is greatly reduced₃ ^2-And Ca²⁺Thereby providing necessary conditions for finally reducing the residual sulfur content and ash content in the finished white granulated sugar product.

(2) The precipitated particles are firm and have good adsorption performance.

The clarification process in sugar production mainly depends on SO₃ ^2-And Ca²⁺Reaction to form CaSO₃Precipitation and PO₄ ^3-And Ca²⁺Reaction to form Ca₃(PO₄)₂The precipitate can adsorb and remove colloid and pigment in the sugar juice. The adsorption capacity of the calcium sulfite precipitation and the calcium phosphate precipitation on the colloidal pigment directly influences the clarification and decoloration effects, and the setting degree, namely the density of the precipitation particles directly influences the sedimentation performance of the precipitation particles. CaSO is generated in the reaction of sulfitation and neutralization juice₃Crystal nuclei of precipitation of SO₃ ^2-And Ca²⁺The reaction is more sufficient and rapid, the reaction is more sufficient, and the generated CaSO is generated₃The sediment particles are firm, the sedimentation speed is high, the mud juice volume is small, and the filtering performance is good. On the other hand, because the reaction speed is high, the surfaces of formed precipitated particles are fresh, the particles have strong adsorption capacity on colloid, pigment and other impurities in the cane juice, and the clarification and decoloration effects of the cane juice are improved. In addition, SO₃ ^2-And Ca²⁺Reaction to form CaSO₃The reaction speed of the precipitate is high, SO that SO is generated₂Absorption chargerRespectively, increase SO₂Utilization ratio of (2); at the same time, SO₂The rapid and stable absorption can also maintain the pH value of the system to be stable, and the problem that the sucrose is lost due to the conversion of sucrose caused by local over-acid or the quality of the sugarcane juice is influenced due to the decomposition of reducing sugar caused by local over-alkali is avoided.

(3) The pollution of the discharged tail gas to the environment is reduced, and the consumption of sulfur is reduced.

After the stoving neutralization reactor, the tail gas also contains a great deal of SO₂Is not absorbed, and if the tail gas is directly discharged, on one hand, the environment pollution is caused, and on the other hand, SO is caused₂The waste increases the sulfur consumption; the invention leads SO in the tail gas to be₂Is absorbed again, on one hand, the pollution of the discharged tail gas to the environment can be reduced, and on the other hand, SO can be fully utilized₂The usage amount of sulfur is reduced by 0.3 to 2 percent compared with the prior art.

The difference between the present invention and the Chinese patent CN200910308507.2 is that:

(1) the process route is different: the above patent utilizes SO₂The tail gas is subjected to two times of stoving neutralization reaction, and SO in the tail gas₂Simultaneously adding into the sugar juice which has been subjected to the first sulfitation, and performing a second sulfitation neutralization reaction. The invention uses SO in the tail gas₂Introducing into a spray-type or tower-plate-type absorption device, introducing the absorption mixed liquor into fresh lime milk, and adding the lime milk into a first sulfitation neutralization reactor, but not adding SO₂Directly introducing into the sugar juice which has undergone the first sulfitation neutralization reaction for the second sulfitation.

(2) The mechanism of action is different: the above patent uses tail gas to carry out secondary sulfitation neutralization reaction, and generates impact and turbulence by stirring and mixing. The present invention is a part of Ca (OH)₂And SO in the tail gas₂Reaction due to SO₂Low concentration, formation of fine CaSO₃Precipitating particles which become SO during the sulphitation neutralization of cane juice₃ ^2-And Ca²⁺CaSO formed by the reaction₃Crystal nuclei of precipitation of SO₃ ^2-And Ca²⁺The reaction is more complete,Quickly and greatly reduce SO in the neutralized juice₃ ^2-And Ca²⁺The residual amount of (this is the main innovation of this application), thus provide the prerequisite for reducing the residual sulfur content and ash content in the finished white granulated sugar.

(3) The effect produced is different: SO in the above patent₂The tail gas is mixed with Ca (OH) in the sugar juice₂Neutralization reaction to form CaSO₃CaSO formed in sugar juices₃Can not be used as crystal nucleus and SO can not be accelerated₃ ^2-And Ca²⁺Reaction, and SO of the tail gas in the present invention₂And Ca (OH)₂Reaction to produce CaSO₃Is in lime milk solution (Ca (OH)₂Solution) and then added to the sugar juice of the first sulphitation treatment, CaSO being formed in lime milk₃Can be used as crystal nucleus to accelerate SO₃ ^2-And Ca²⁺And (4) reacting.

Drawings

FIG. 1: the invention relates to a process flow chart.

Detailed Description