Background technology
Chitin is also called chitin, chitin, and chemistry β-(1-4)-2-acetylaminohydroxyphenylarsonic acid 2-deoxy-D-glucose by name, has important application prospect in weaving, chemical industry, food, medicine and other fields.Chitin is mainly present in the shell of crustacean, the cell wallss etc. of fungi such as lower plant mushroom, shrimp, crab, insect.The main raw material of current suitability for industrialized production is shrimp, crab shell.
The production process of chitin mainly contains two operations, first operation is decalcification operation, ash content mainly calcium carbonate in shrimp, crab shell, the subtractive process of calcium carbonate joins in certain density hydrochloric acid by shrimp, crab shell, in shrimp, crab shell, calcium carbonate and hydrochloric acid reaction change the calcium chloride of solubility into, thus remove the calcium carbonate in shrimp, crab shell; Another committed step is prawn, the removing of protein in crab shell, and traditional method for removing protein is that shrimp, crab shell are joined concentration is in the diluted sodium hydroxide solution of 4%-10%, soaks 3-5 hour, by proteolytic removing wherein at 60 DEG C.
In decalcification process, for ensureing that the ash content of chitin is reduced to specified requirement, needing to add excessive hydrochloric acid, thus thoroughly removing the calcium in shrimp, crab shell, therefore in decalcification waste liquid, have a large amount of hydrochloric acid residues.
Be at present by the reuse of waste hydrochloric acid solution to the conventional treatment method of hydrochloride waste, concrete way is by waste hydrochloric acid solution and the raw material reaction not having decalcification, and the calcium carbonate reaction in waste hydrochloric acid solution in remaining hydrochloric acid and shrimp, crab shell, carries out pre-decalcification process.Along with the reduction of concentration of hydrochloric acid, speed of response declines gradually, and last remaining hydrochloric acid sodium hydroxide neutralizes.Waste liquid after neutralization is processed further, rear discharge up to standard.This traditional spent acid treatment process, hydrochloric acid wastage is large, in and spent acid need the sodium hydroxide of at substantial, processing cost is high, and waste water generation is large, and in waste water, salt ion content is high, causes disadvantageous effect to the further process of waste water.
Application publication number is that the patent document of CN101974103A discloses a kind of clean preparation process of chitin, describe in this patent document and adopt dynamic circulation in pickling workshop section, acid solution is reused, recycle and reach more than 5 times, the calcareous content in waste water is made to be tending towards adding sulfuric acid again in saturated backward waste water, filter, obtain calcium sulfate, acid waste water reclaims to be used for preparing hydrochloric acid soln.In this patent document, the hydrochloric acid be in acid solution the basis of the recycling of acid solution is excessive, utilizes remaining hydrochloric acid to react with shrimp head shrimp shell again, removes calcium carbonate wherein.Its essence does not break away from traditional waste hydrochloric acid solution processing methods yet---the pre-decalcification process of waste hydrochloric acid solution, only in the production technique of this patent document chitin, the remaining amount of hydrochloric acid is larger, and (residual content is mainly contributed by large solid-liquid ratio 1:8-1:12, in Industrial processes, solid-liquid ratio is generally about 1:2.6), so could circulate more than 5 times.Cycle index is more, needs the amount remaining hydrochloric acid in waste hydrochloric acid solution more, and along with the reduction of concentration of hydrochloric acid in acid solution, reaction efficiency and decalcification effect decline, therefore decalcification process need 10-15 hour.In hydrochloric acid dynamic circulation at the end, add sulfuric acid in waste water, filter, obtain calcium sulfate, acid waste water is used for returning complex acid liquid use, and patent document only achieves the reuse of acid waste water.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, a kind of method that in chitin production process, waste hydrochloric acid regeneration utilizes is provided.After the present invention carries out manipulation of regeneration to the waste hydrochloric acid solution after the process of first time decalcification operation, be directly used in second time decalcification process, waste hydrochloric acid solution after second time decalcification process after manipulation of regeneration for third time decalcification process, recycle successively, the reaction vigor of each reacted hydrochloric acid soln can be made can to return to level close to fresh hydrochloric acid, hydrochloric acid can reuse, and the more important thing is, other decalcification operations except the first step decalcification process do not need additionally to add hydrochloric acid again, can ensure decalcification efficiency and effect yet.
Object of the present invention is achieved by the following technical programs:
A regeneration method for waste hydrochloric acid in chitin production process, described method comprises the steps:
First time manipulation of regeneration: has collected the waste hydrochloric acid solution after first time decalcification operation process, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion and the mol ratio that adds sulfate radical are 1:0.4-2.3; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in second time decalcification process;
The N time manipulation of regeneration: collected the waste hydrochloric acid solution after the process of the N time decalcification operation, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the N+1 time decalcification process; N be more than or equal to 2 natural number, repeat manipulation of regeneration, can not till reprocessing makes chitin ash content≤3.0% until regenerant salt acid solution.
In chitin production process, collect waste hydrochloric acid after the process of each decalcification operation, add moderate amount of sulfuric acid, control calcium ion and the mol ratio adding sulfate radical in waste hydrochloric acid solution, carry out the regeneration of hydrochloric acid soln, and for after decalcification operation once, the reaction vigor of each reacted hydrochloric acid soln can return to the level close to fresh hydrochloric acid, and hydrochloric acid can reuse, do not need to add hydrochloric acid, ensure decalcification efficiency and effect, reduce the generation of waste water simultaneously, realize the cleaner production of chitin.
Preferably, the mass concentration of described sulphuric acid soln is 40-98%.
Preferably, the step of described precipitation is add sulphuric acid soln, stirring velocity 20-60 rpm in the discarded hydrochloric acid after filtering and impurity removing, and limit edged stirs, and sulfuric acid added in 30 minutes, after sulfuric acid adds, continues to stir 10-30 minute, makes to react completely.
Preferably, described growing the grain step is, after precipitin reaction terminates, waste hydrochloric acid and sulfuric acid mixture is left standstill 1-3 hour, carries out growing the grain process.Operate by described method, calcium sulfate precipitation forms larger crystallization, is beneficial to filter operation.
Preferably, described N is 3,4,5,6,7,8.Regenerative process as N=5 is: the 1st manipulation of regeneration, collect the waste hydrochloric acid solution after the 1st decalcification operation process, after filtration after removal of impurities, in waste hydrochloric acid solution, add sulphuric acid soln, in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the 2nd decalcification process;
2nd manipulation of regeneration: collected the waste hydrochloric acid solution after the 2nd decalcification operation process, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the 3rd decalcification process;
3rd manipulation of regeneration: collected the waste hydrochloric acid solution after the 3rd decalcification operation process, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the 4th decalcification process;
The 4th manipulation of regeneration: collected the waste hydrochloric acid solution after the process of the 4th decalcification operation, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the 5th decalcification process;
The 5th manipulation of regeneration: collected the waste hydrochloric acid solution after the process of the 5th decalcification operation, waste hydrochloric acid solution, after filtration after removal of impurities, adds sulphuric acid soln in waste hydrochloric acid solution, and in waste hydrochloric acid solution, calcium ion is 1:0.4-2.3 with the mol ratio adding sulfate radical; Regeneration of hydrochloric acid is realized through precipitation, growing the grain, filtration; Hydrochloric acid after regeneration does not need to add hydrochloric acid in addition can be directly used in the 6th decalcification process.
Preferably, the temperature of reaction of described method is room temperature.
Preferably, employing suction filtration, centrifuging or press filtration is filtered described in S1 and S4.
Preferably, stir process described in S2 is carried out in the enamel reaction still of band whipping appts, and described reactor inside scribbles ceramic layer, avoids by acid corrosion.
Compared with prior art, the present invention has following beneficial effect:
(1) the method for the invention regenerates the waste hydrochloric acid solution after the process of each decalcification operation, and regeneration hydrochloric acid can reuse, and does not need to add hydrochloric acid, ensures decalcification efficiency and effect, reduces the generation of waste water simultaneously, realize the cleaner production of chitin.
(2) the present invention has broken away from the treatment process of traditional waste hydrochloric acid, (5.1wt% under the condition of normal hydrochloric consumption needed for suitability for industrialized production, the solid-liquid ratio of dry shrimp head shrimp shell and hydrochloric acid soln is 1:13, and the water content of wet shrimp head shrimp shell is about 80%, if the solid-liquid ratio being scaled wet shrimp head shrimp shell is 1:2.6), the recycling utilization of hydrochloric acid can be realized.
(3) the present invention is to calcium ion in solution and the mol ratio adding sulfuric acid, the concentration of sulfuric acid, reaction stirring velocity, in the reaction times, the standing rearing crystal time of calcium sulfate precipitation etc. have strict requirement, avoid misoperation and make whole waste hydrochloric acid solution present pasty state, cause regenerating the unsuccessfully phenomenon that cannot reuse, achieve the recycling utilization of hydrochloric acid, with former inventive method---, there is essential distinction in the reuse of acid waste water.
(4) regenerant salt acid solution of the present invention can the decalcification operation in chitin production process recycle, and the time is short, and efficiency is high.
(5) the present invention can reduce chitin production cost, significantly improves the productivity effect of chitin enterprise; Reduce the waste water generation in chitin production process, reduce environmental pollution, there is good economic benefit and social benefit.
embodiment
Below in conjunction with Figure of description and specific embodiment, the present invention is described in further details, but embodiment does not limit in any form the present invention.Unless stated otherwise, the present invention adopts reagent, method and apparatus are the art conventional reagent, method and apparatus.
embodiment 1
First time regeneration
It is in the hydrochloric acid soln of 5.1wt% that dry shrimp shell is joined concentration, and the amount added is 1:13(mass volume ratio), stirred at ambient temperature reacts 4 hours, carries out the decalcification reaction of shrimp shell.Isolate the shrimp shell after decalcification after reaction terminates, obtain decalcification waste hydrochloric acid solution.Cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.13 mole often liter, get waste hydrochloric acid solution 1000 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:1.2 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 19.2 kilograms of 80% concentration, limit edged stirs, and stirring velocity is 30 rpms, and sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 30 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the first time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.34%.
Second time regeneration
Get the waste hydrochloric acid solution after first time regenerant salt acid solution decalcification, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, recording calcium ion concn in this hydrochloric acid soln is 0.17 mole often liter, get waste hydrochloric acid solution 800 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:1.2 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 16.4 kilograms of 98% concentration, limit edged stirs, stirring velocity is 30 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 30 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the second time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.41%.
Third time regeneration
Get the waste hydrochloric acid solution after the decalcification of second time regenerant salt acid solution, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.16 mole often liter, get waste hydrochloric acid solution 700 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:0.4 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 11.0 kilograms of 40% concentration, limit edged stirs, stirring velocity is 20 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 15 minutes.After reaction terminates, stop stirring, mixture leaves standstill 1.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the third time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.45%.
embodiment 2
First time regeneration
It is in the hydrochloric acid soln of 5.1wt% that dry shrimp head after oven dry is joined concentration, and the amount added is 1:13(mass volume ratio), stirred at ambient temperature reacts 4 hours, carries out the decalcification reaction of shrimp shell.Isolate the shrimp head after decalcification after reaction terminates, obtain decalcification waste hydrochloric acid solution.Cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.12 mole often liter, get waste hydrochloric acid solution 1000 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:1.2 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 15.7 kilograms of 90% concentration, limit edged stirs, and stirring velocity is 50 rpms, and sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 20 minutes.After reaction terminates, stop stirring, mixture leaves standstill 3 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the first time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp head by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp head after decalcification, and the chitin ash content obtained is 0.32%.
Second time regeneration
Get the waste hydrochloric acid solution after the decalcification of first time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.16 mole often liter, get waste hydrochloric acid solution 800 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:1.0 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 7.0 kilograms of 90% concentration, limit edged stirs, stirring velocity is 50 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 15 minutes.After reaction terminates, stop stirring, mixture leaves standstill 1 hour, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the second time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp head by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp head after decalcification, and the chitin ash content obtained is 0.38%.
Third time regeneration
Get the waste hydrochloric acid solution after the decalcification of second time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.15 mole often liter, get waste hydrochloric acid solution 700 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:0.5 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 10.3 kilograms of 50% concentration, limit edged stirs, stirring velocity is 25 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 18 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the third time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp head by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp head after decalcification, and the chitin ash content obtained is 0.46%.
4th regeneration
Get the waste hydrochloric acid solution after the decalcification of third time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.12 mole often liter, get waste hydrochloric acid solution 500 liters, adding volume is in the enamel reaction still of 2 cubes, start motor to stir, be 1:2.3 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 22.5 kilograms of 60% concentration, limit edged stirs, stirring velocity is 40 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 12 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 4th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp head by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp head after decalcification, and the chitin ash content obtained is 0.51%.
5th regeneration
Get the waste hydrochloric acid solution after the decalcification of the 4th regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.13 mole often liter, get waste hydrochloric acid solution 400 liters, adding volume is in the enamel reaction still of 1 cube, start motor to stir, be 1:0.9 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 4.7 kilograms of 98% concentration, limit edged stirs, stirring velocity is 60 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 30 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 5th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp head by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp head after decalcification, and the chitin ash content obtained is 0.81%.
embodiment 3
First time regeneration
It is in the hydrochloric acid soln of 5.1wt% that dry shrimp shell after oven dry is joined concentration, and the amount added is 1:13(mass volume ratio), stirred at ambient temperature reacts 4 hours, carries out the decalcification reaction of shrimp shell.Isolate the shrimp shell after decalcification after reaction terminates, obtain decalcification waste hydrochloric acid solution.Cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.13 mole often liter, get waste hydrochloric acid solution 2000 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:1.1 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 30.5 kilograms of 92% concentration, limit edged stirs, and stirring velocity is 50 rpms, and sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 20 minutes.After reaction terminates, stop stirring, mixture leaves standstill 3 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the first time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.35%.
Second time regeneration
Get the waste hydrochloric acid solution after the decalcification of first time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.16 mole often liter, get waste hydrochloric acid solution 1700 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:1.0 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 29.5 kilograms of 90% concentration, limit edged stirs, stirring velocity is 50 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 25 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the second time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.39%.
Third time regeneration
Get the waste hydrochloric acid solution after the decalcification of second time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.15 mole often liter, get waste hydrochloric acid solution 1500 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:0.6 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 26.5 kilograms of 50% concentration, limit edged stirs, stirring velocity is 20 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 18 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the third time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.45%.
4th regeneration
Get the waste hydrochloric acid solution after the decalcification of second time regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.16 mole often liter, get waste hydrochloric acid solution 1200 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:2.1 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 65.9 kilograms of 60% concentration, limit edged stirs, stirring velocity is 28 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 10 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 4th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.55%.
5th regeneration
Get the waste hydrochloric acid solution after the decalcification of the 4th regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.14 mole often liter, get waste hydrochloric acid solution 1000 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:0.8 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 13.7 kilograms of 80% concentration, limit edged stirs, stirring velocity is 44 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 27 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 5th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 0.79%.
6th regeneration
Get the waste hydrochloric acid solution after the decalcification of the 5th regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.15 mole often liter, get waste hydrochloric acid solution 800 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:0.7 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 16.5 kilograms of 50% concentration, limit edged stirs, stirring velocity is 20 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 20 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the third time regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 1.15%.
7th regeneration
Get the waste hydrochloric acid solution after the decalcification of the 6th regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.16 mole often liter, get waste hydrochloric acid solution 700 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:2.1 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 28.8 kilograms of 80% concentration, limit edged stirs, stirring velocity is 25 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 15 minutes.After reaction terminates, stop stirring, mixture leaves standstill 2 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 4th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 1.52%.
8th regeneration
Get the waste hydrochloric acid solution after the decalcification of the 7th regeneration hydrochloric acid, cross the chitin filtered in waste hydrochloric acid solution, fiber, stone solid sundries, obtain decalcification waste hydrochloric acid solution, recording calcium ion concn in this hydrochloric acid soln is 0.14 mole often liter, get waste hydrochloric acid solution 500 liters, adding volume is in the enamel reaction still of 3 cubes, start motor to stir, be 1:0.8 by calcium ion and sulfate radical mol ratio, slowly add the sulphuric acid soln 5.6 kilograms of 98% concentration, limit edged stirs, stirring velocity is 35 rpms, sulfuric acid added in 30 minutes, after sulfuric acid adds, continue stirring reaction 20 minutes.After reaction terminates, stop stirring, mixture leaves standstill 1.5 hours, is crossed by calcium sulfate precipitation filter by flame filter press, obtains the 8th the regenerant salt acid solution clarified.Regenerant salt acid solution carries out the decalcification process of shrimp shell by the decalcification processing condition of fresh hydrochloric acid, carries out deproteinated process, obtain chitin after oven dry to the shrimp shell after decalcification, and the chitin ash content obtained is 2.05%.
Table 1 hydrochloric acid recycling table
Note: 1, solid-liquid ratio is the mass volume ratio of dry shrimp head and hydrochloric acid soln; The dry matter content of wet shrimp head shrimp shell is about 20%.
2, "-" expression does not add new hydrochloric acid.
According to the quality index of national marine industry standard SC/T3403-2004 chitin, food grade chitin ash content≤1.0%, technical grade chitin ash content≤3.0%, the decalcification that the hydrochloric acid therefore utilizing the present invention to regenerate carries out chitin processes the specification of quality that enough all can meet chitin.