Title of Invention

A PROCESS FOR TREATMENT OF DILUTE SULFURIC ACID CONTAINING EFFLUENT USING ION EXCHANGE RESIN

Abstract The process for treatment of lean sulfuric Acid containing effluent generated by processes such as sulfonation, pickling & acid catalysis by using porous Ion exchange adsorbent to simultaneously remove colors, organics and acids from the effluent making it suitable for recycle and it also regenerates the adsorbent using ammonia and recover the regenerant ammonia for reuse making process economical.
Full Text FORM-2
THE PATENTS ACT. 1970 (39 of 1970)
COMPLETE SPECIFICATION
(Section 10, rule 13)
“Method for the Recycle of Acidic waste water and effective use of regenerant”
Thermax Limited
with Corporate office at Thermax House, 4 Pune-Mumbai Road, Shivajinagar, Pune 411005,
Maharashtra, India.
an Indian Company registered under the provisions of the Companies Act, 1956,
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED: -

FIELD OF THE INVENTION
The present invention relates to the process for treatment of lean sulfuric Acid containing effluent
Particularly, the present invention relates to the process for treatment of lean sulfuric Acid containing effluent using Ion exchange resin.
More particularly, the present invention relates to the process for treatment of lean sulfuric Acid containing effluent using Ion exchange resin thereby making it possible to recycle water.
Even more particularly, the present invention relates to the process for treatment of lean sulfuric Acid containing effluent using porous ion exchange adsorbent for removal of colors, organics and acids from the effluent making it suitable for recycle.
The invention also relates to the regeneration of the adsorbent using ammonia and recovery of the regenerant ammonia for reuse.
BACKGROUND OF THE INVENTION
Ion exchange processes generally involve a reversible chemical reaction between a solid ion exchanger and an aqueous solution whereby ions are interchanged between the
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exchanger and the solution. The most widely used exchangers are ion exchange resins which comprise, for the most part, insoluble organic polymer matrices having attached functional groups which provide mobile ions which may be exchanged for ions in the solution bearing the same charge. To impart increased stability to the resins, the matrices are usually prepared by addition copolymerization reactions which provide varying degrees of crosslinking. Depending upon the nature of the functional group, ion exchange resins are classified broadly as strong acid, weak acid, strong base and weak base. The acid exchange resins are further classified as cation exchangers while the base exchange resins are usually referred to as anion exchangers.
Strong acid cation exchange resins typically comprise sulfonated copolymerized styrene-divinylbenzene products crosslinked to varying degrees. Such resins are widely used in water conditioning, demineralization of syrups, chromatographic separations, and metal recovery.
Weak acid cation exchange resins are commonly prepared by reacting an unsaturated carboxylic acid, e.g., acrylic or methacrylic acid, with a crosslinking agent such as divinylbenzene or ethylene dimethacrylate. Functional groups may comprise phenolic, phosphorous or carboxylic entities, combinations of these and others. Weak acid resins have found application in water conditioning, chromatographic separation, and metal recovery.
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Strong base anion exchange resins generally are prepared by affixing quaternary ammonium groups to a polystyrene divinylbenzene matrix. Resins of this type are used principally in water conditioning.
Weak base anion exchange resins contain primary, secondary and tertiary amine groups or mixtures of such groups. Such resins are available in a variety of types including condensation products of amines with formaldehyde, alkyl dihalides, chloromethylated styrene-divinylbenzene, etc.
PRIOR ART
An U.S. patent application No. 5,059,406 claiming a flue gas desulphurization process involving the generation of a flue gas product form the combustion of a fossil fuel wherein the flue gas contains sulfur oxides and halogen compounds produced as a result of the combustion of the fuel and wherein an alkali metal compound is contacted with the flue gas resulting in the removal of sulfur oxides from the gas and formation of a water-soluble residue comprising an alkali metal sulfate and alkali metal halides, which residue is collected from the flue gas before the flue gas is released to the environment, and the recovery of the alkali metal ions from the collected residue for use in supplying the alkali metal compound that is contacted with the gas, the improvement comprising dissolving the collected residue in water to form an aqueous solution thereof having a pH of less than about 8 so that sulfate ions, halogen ions and alkali metal ions are present therein, and thereafter contacting the solution with a weak base anion-exchange resin having bicarbonate groups associated
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therewith that exchange with sulfate and halogen ions in the solutions so that the sulfate and halogen ions become associated with the resin and the bicarbonate groups become associated with the alkali metal ions in the solution, whereby the alkali metal ions are separated from the sulfate ions and halogen ions for use in supplying the alkali metal compound that is contacted with the gas
An U.S. patent application No. 5,434,301 claiming A process for the separation of sulfuric acid from a mixture, said process comprising:
contacting a liquid mixture comprised of sulfuric acid and a water soluble naphthalene-based material selected from the group consisting of naphthalenesulfonic acids, lower-alkyl substituted naphthalenesulfonic acids, and mixtures thereof, with a basic anion exchange resin in essentially the sulfate form to provide a raffinate liquid phase depleted with respect to said mixture in sulfuric acid;
removing said raffinate liquid phase from contact with said basic anion exchange resin;
contacting said basic anion exchange resin with an aqueous liquid at an essentially neutral pH to form an extract liquid phase consisting essentially of sulfuric acid;
and removing said extract liquid phase from contact with said basic anion exchange resin
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An U.S. patent application No. 4,572,746 claiming For use in connection with the manufacture of storage battery plates, a process for removing acid from the plates, comprising the steps of:
(a) washing the plates in flowing water until most of the acid has been removed from the plates at a water flow rate which is lower than that of a subsequent washing of step (b);
(b) thereafter, removing additional acid from the battery plates by washing said plates in additional flowing water at a water flow rate producing an acid concentration in the additional wash water less than that produced in step (a) above;
(c) discharging the additional wash water resulting from step (b) and treating said discharged water to remove the acid therefrom; and
(d) using the treated water from step (c) for washing in at least one of said washing steps (a) and (b).
An U.S. patent application No. 6,159,376 claiming a method and apparatus for the treatment of wastewater effluent from a laundromat which combines multiple filtering, particularly including, bag filters, to remove particulates including fine particulates followed by treatment in a weak base anion exchange resin bed to remove MBAS. The weak base resin was found to remove MBAS and organics such as LAS which were highly de-adsorbed in the
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(b) thereafter, removing additional acid from the battery plates by washing said plates in additional flowing water at a water flow rate producing an acid concentration in the additional wash water less than that produced in step (a) above;
(c) discharging the additional wash water resulting from step (b) and treating said discharged water to remove the acid therefrom; and
(d) using the treated water from step (c) for washing in at least one of said washing steps (a) and (b).
An U.S. patent application No. 6,159,376 claiming a method and apparatus for the treatment of wastewater effluent from a laundromat which combines multiple filtering, particularly including, bag filters, to remove particulates including fine particulates followed by treatment in a weak base anion exchange resin bed to remove MBAS. The weak base resin was found to remove MBAS and organics such as LAS which were highly de-adsorbed in the efficient regeneration of the resin. The weak base anion exchange resin is preferably macroporous in the sulfate form. The invention contemplates multiple bag filters of different degrees of coarseness.
An U.S. patent application No. 3,982,956 claiming a process which comprises the steps of treating sugarbeet juice, after second carbonation, with the hydrogen form of a resinous carboxylic-type cation exchanger arranged in a column for the reduction of calcium
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ion in the juice, and thereupon passing the so-treated juice through a mass of particles of a weakly basic anion exchanger having a tertiary amine functionality and operated over the hydroxyl form. The process wherein the weakly basic anion exchanger being exhausted with the sugar juice is first stripped with the acidic waste regeneration solution from the carboxylic type cation exchanger prior to the conversion of the weakly basic anion exchanger to its respective hydroxyl form via regeneration with aqueous ammonia. The process wherein ammonia used for the regeneration of the weakly basic anion exchanger is recovered for reuse by treating the waste solution from said weakly basic anion exchanger with lime representing a nearly stoichiometric quantity on the amount of ammonium ions present in the weakly basic anion exchange waste solution; and distilling, collecting, and condensing the ammonia vapors to form ammonium hydroxide for reuse in the regeneration procedure
An U.S. patent application No. 4,172,185 describes a process for regenerating exhausted weak base anion exchange resins which have been contacted with a regenerant solution under conditions whereby the anion exchange capacity of the resins is substantially restored and regenerant waste products are produced, the improvement comprising sequentially washing the resins with water to remove a portion of the regenerant waste products and then washing the resins with a solution of carbonic acid to remove additional amounts of regenerant waste products. The regenerant is selected from the group consisting of solutions of NaOH, Na.sub.2 CO.sub.3 and aqueous NH.sub.3.
However, the above prior art is limited in its scope and application as they either advice treating acidic waste water which would eventual generate high TDS effluent or
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recommend a process of organic removal from this acidic effluent which otherwise will end up as COD in effluent.
The process of removal of sulfuric acid and other acids by using weakly basic resin already exists and is widely applied commercially for demineralization. As seen from above, the US patent 5059406 describes the sulfate removal in desulfurizing process. Also, another US Pat.No.5434301 and 4,572,746 describe the up take of sulfuric acid by strongly as well as weakly basis resin. The demineralization process use weakly basic resins & strong acid cation to remove the mineral acids.
The process of adsorbing color by weakly basic Macrospores resins is described in US pat.No.6,159,376 in which methylene blue active substances were used for the studies. The effect of porosity on the adsorption of color is described in various papers and publications. The process of regeneration by NaOH is commonly used but this regeneration method produce high TDS effluent. The process of regeneration with ammonia and NaOH is described in US pat. No. 5059406, US.Pat.No 3,982,956 and U.S.Pat. No. 4172.185.
Another method of treating acidic effluent is by distillation & recycle water. However, it is not economical to concentrate the acid due to the high distillation cost. This low concentration acidic effluent is commonly neutralized using soda ash, caustic soda or lime in effluent treatment plants. This acid generates very high TDS containing effluent after neutralization in the range of 0.25% to 0.5% which is not acceptable as per discharge norms.
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Moreover, any further processes of removing salts, such as Reverse osmosis or distillation, are cost prohibitive. Hence, the objective of this invention is to provide for a cost effective and economically feasible method of removing salts from affluent while recycling the Acidic waste water by effectively using regenerant.
OBJECTS OF THE INVENTION
The object of this invention is to develop a process for treatment of lean sulfuric Acid containing effluent
Another object of this invention is to develop a process for treatment of lean sulfuric Acid containing effluent using Ion exchange resin.
Another object of this invention is to develop a process for treatment of lean sulfuric Acid containing effluent using Ion exchange resin thereby making it possible to recycle water.
Another object of this invention is to develop a process for treatment of lean sulfuric Acid containing effluent using porous ion exchange adsorbent for removal of colors, organics and acids from the effluent making it suitable for recycle.
Another object of this invention is to develop a process for the regeneration of the adsorbent using ammonia and recovery of the regenerant ammonia for reuse.
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SUMMARY OF THE INVENTION
The present invention relates to the process for treatment of lean sulfuric Acid containing effluent using porous ion exchange adsorbent for removal of colors, organics and acids from the effluent making it suitable for recycle. It is also endeavor of this patent to regenerate the adsorbent using ammonia and recover the regenerant ammonia for reuse.
Many industries such as lead battery, sulfuric acid , pickling bath; Acid catalysis have dilute sulfuric acid in effluent in range of 0.1 to 0.5%. It is not economical to concentrate the acid due to the high distillation cost. This low concentration acidic effluent is neutralized using soda ash, caustic soda in effluent treatment plants. This acid generates the very high TDS containing effluent after neutralization in the range of 0.25% to 0.5% which is not acceptable as per discharge norms. The further processes of removing salts such as Reverse osmosis or distillation are cost prohibitive.
The present process for treatment of lean sulfuric acid containing effluent, using Ion exchange resin comprising the steps of filtration to remove suspended solids, then passing the filtered effluent through a bed of anionic weakly basic adsorbent for removing acid by ion exchange and then again passing through anionic adsorbent bed simultaneously remove organics & colors from effluent and then recovering water after removing simultaneously acid and many organics and colors from the effluent and then backwashing adsorbent after exhaustion to remove any particulate matter and regeneration using ammonia and washing the adsorbent with water to remove the excess ammonia regenerant and then collecting the regenerant & wash water for recovery of ammonia and then recovering the regenerant, using
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alkali; preferably lime, in the form ammonia and recovering the liberated ammonia by filtration to eliminate precipitated Calcium sulphate & washing the calcium sulfate cake with water to recover the ammonia or recovering the liberated ammonia by distillation to eliminate the organic eluted during regeneration & eliminate precipitated calcium sulphate by filtration and finally using the recovered ammonia for subsequent regeneration.
DETAILED DESCRITION OF THE INVENTION
Many industries such as lead battery, sulfuric acid , pickling bath; Acid catalysis have dilute sulfuric acid in effluent in range of 0.1 to 0.5%. It is not economical to concentrate the acid due to the high distillation cost. This low concentration acidic effluent is neutralized using soda ash, caustic soda in effluent treatment plants. This acid generates the very high TDS containing effluent after neutralization in the range of 0.25% to 0.5% which is not acceptable as per discharge norms. The further processes of removing salts such as Reverse osmosis or distillation are cost prohibitive.
The process of removal of sulfuric acid and other acids by using weakly basic resin already exists and is widely applied commercially for demineralization. There are methods for sulfate removal in desulfurizing process. There are also methods that describe the up take of sulfuric acid by strongly as well as weakly basis resin. The demineralization process use weakly basic resins & strong acid cation to remove the mineral acids. The process of adsorbing color by weakly basic Macrospores resins is also known in which methylene blue
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active substances were used for the studies. The effect of porosity on the adsorption of color is described in various papers and publications.
The process of regeneration by NaOH is commonly used but this regeneration method produce high TDS effluent. The process of regeneration with ammonia and NaOH is described and known and also the process of production of ammonia by addition of lime is described in classical inorganic chemistry.
However, it is not economical to concentrate the acid due to the high distillation cost. This low concentration acidic effluent is neutralized using soda ash, caustic soda in effluent treatment plants. This acid generates very high TDS containing effluent after neutralization in the range of 0.25% to 0.5% which is not acceptable as per discharge norms. Moreover, any further processes of removing salts, such as Reverse osmosis or distillation, are cost prohibitive. Therefore this invention provides a cost effective and economically feasible method of removing salts from Affluent while recycling the Acidic waste water by effectively using regenerant.
PROCESS DESCRIPTION
Step 1: Removal of acid - The present invention use porous weakly basic anionic adsorbent to remove acids from the effluent. The effluent after due filtration preferably using acid stable deep bed media filtration; is passed through a bed of anionic weakly basic adsorbent; styrenic or acrylic, preferably styrenic macroporous or gel preferably macroporous with area from 15
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to 35 sqm/gm; preferably 25 sqm/gm at 2 to 30 m/hr specific flow; preferably 5 to 15 m/hr flow ; the bed height of adsorbent is from 600 to 1200 mm preferably 800 mm. The resin bed removes the acidic anions such as chloride, sulfate, phosphates and nitrates from acid effluent. The effluent from the anionic adsorbent bed has pH in range of 6 to 7 which can be recycled for reuse or washing.
Example 1: Effluent containing 5000 (V)mg/e sulfuric acid & dark brown color was passed through 600 mm high bed at 10 bed volume per hour velocity in a one inch diameter column containing 300 ml of resin. The effluent from the bed has pH in range of 6 to 7. The adsorbent treated 3.0 lit of effluent. The run termination point was emergence of acidic pH at column outlet, i.e. when pH dropped down to 5. The recovered water was colorless with sulfates less than 30 mg/e and quality was suitable for recycle .
Step 2: Recovery of water: In the present invention, water is recovered after removing simultaneously acid and many organics and colors from the effluent. Anion resins are used in demineralization for removal of natural organics such as humic acids and tannins. It is also known that, anion resin in weakly basic, type II and strongly basic both in gel macroporous remove organics. Both acrylic, styrenic base resins are used for organic removal. The resin used in the said invention for organic removal are anion resins weakly basis, macroporous or gel preferably macroporous; styrenic or acrylic, preferably styrenic. The surface area used for color & organics removal varies from negligible in case of gel resin to 600 sqm/gm of resin which depend on the nature of organics
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Example 2: The organics containing effluent in example 1 was dark colored effluent, passed through a bed of 300 ml of resin at 10 BV/hr flow. The adsorption resin used was having area of 27 sqm/gm of resin. COD level of the water was brought down from 1000 mg/e to 100 mg/e TDS was less than 200, water was practically clear and pH of water is range of 6.8 to
7.5.
Step 3: Regeneration: The present invention use ammonia for regeneration. 0.5 to 10 % solution of ammonia is used preferably 5 %, with 120 to 170 % excess over the capacity of adsorbent for acid is used; preferably 130 %. The Adsorbent is first washed with water, backwashed to remove any particulate matter followed by regeneration. The regeneration is done as 2 to 7 bed volume flow rate; preferably 2 BV/hr flow. The adsorbent is washed with water at 5 to 15 BV preferably at 7 BV and the wash water is collected for recovery of excess ammonia.
Example 3: After exhaustion of the resin as given in example 1. Back wash is given by water to remove the particulate matter so as to get 50% expansion of the bed for 15 min. After settling the resin, 122.4 g of 5% ammonia solution at flow rate of 2 BV/hr is passed. After ammonia passage resin bed is washed with 2 BV of water to remove the excess of ammonia. The Operating capacity of this regenerated resin was 50 g per lit. of resin
Step 4: Recovery of regenerant -The present invention gives process for recovery of ammonia using alkali such as NaOH, KOH and lime; preferably lime. The spent regenerant from the process of regeneration described above; contain salts of ammonia such as ammonium
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sulfate, ammonium Sulfates at 3 to 10% concentration. The concentration of ammonium sulfate can vary depending on the concentration of ammonia used for regeneration. The alkali is added to the process either by making solution or as solid. The quantity of alkali is 110 to 200%; preferably 120% of the stoinchiometric requirement of the ammonium salts. The mixture of alkali and regenerant is heated for 60 to 100 deg.C temp preferably 90 deg.C temp to liberate ammonia. This liberated ammonia is recovered by filtration or distillation, preferably by distillation to eliminate the organics eluted during regeneration.
Example 4: After regeneration of resin the spent regenerant mainly contains the sulfate. 300 ml of spent regenerant is obtained from the resin in example 1. Spent regenerant is combination of regeneration solution and wash water. The spent regenerant is ammonium sulfate having 7% concentration which is further reacted with 13 g of lime for about one hour at room temperature. The librated ammonia is filtered and Calcium sulfate cake is washed with water to recover the ammonia. The 90 % of theoretical ammonia is recovered in filtrate at concentration of 1.62%.
Recovery of ammonia by present process invention can also be done by distillation. Addition of lime forms calcium sulfate and the free ammonia. United States Patent 3982956 sates that the ammonia can be distilled and reused for next regeneration. The vapors of ammonia form azeotropic mixture with water & 7% ammonia at 90 deg C.
The mixed regenerant and alkali as given in step 5 above is heated to boil and the vapors and ammonia gas liberated is scrubbed by water to dissolve ammonia. The recovered
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ammonia from scrubber has concentration in rage of 0.5 to 7% preferably 2 to 6 %. This recovered ammonia is recycle for regeneration in as described in step 3. In this process organic contaminants and colors are left behind in the residue of distillation.
Example 5: The mixture after reaction with lime as stated in example 4, instead of filtration,
is distilled to recover the ammonia. The ammonia is scrubbed and the measured by titration.
87 % ammonia is recovered as distillate. 500 ml of 9% ammonium sulfate which is obtained
after regeneration is neutralized by 28.1 g of lime and distilled out the ammonia with due care
of scrubbing the ammonia. Water quantity for scrubbing is adjusted to Scrubbed ammonia
solution, which is 200 ml, is re-circulated to increase the concentration of ammonia. After
complete distillation the ammonia recovery obtained is 87% and the concentration of
ammonia found to be 5.3%. and was clear solution.
The residue was dark colored calcium sulfate slurry containing not detectable ammonia. This is filtered to remove the excess of water and disposed as sludge.
Different regenerating agents can be used to regenerate the weakly basic resin like caustic, sodium carbonate and other alkalis. Use of such alkali can lead to give soluble salts of the respective alkali, which may lead to effluent problem again since those respective salts contribute to the effluent. But same can be used where water costs are very high and one can afford to send this TDS to the effluent.
Step 5: Recycle of regenerant: The important aspect of the invention is to use this recovered ammonia for subsequent regeneration. The process of regeneration is to use recovered
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ammonia after adjustment of concentration as mentioned in example 3 above for regeneration with fresh ammonia. Thus right concentration ammonia liquor is used for the regeneration as described above and in step 3.
Process of filtration of calcium sulfate is simple user friendly, which yields the ammonia solution which can be reusable. We found that the leached colored organics in regenerant can be very well trapped by the calcium sulfate which in turn gives the clear liquor for the next regeneration. The other cause of the color to the water can be due to the some of the metal ions present in the effluent which also gets precipitated and get removed as sludge.
The process is further made simple; we found that the hardness due to the soluble calcium sulfate and un-reacted lime do not cause the resin capacity drop, due to the precipitation of calcium sulfate on the resin.
Example 6: The recovered ammonia after filtration in example 4 above was mixed with 25% fresh ammonia liquor to adjust concentration to 5 %. The hardness checked in the recovered ammonia and found 1300 mg/e The regeneration was done as per the step 3 above. The hardness of the liquor after regeneration was 1280 mg/e & thus almost all hardness is retained in soluble form showing no entrapment of hardness on the resin. The capacity of the resin was nearly same as obtained by use of fresh ammonia as regenerant.
Example 7 : Recycle of ammonia recovered by distillation : Recovered ammonia as obtained in example 5 is used to regenerate the exhausted resin column with out making any further
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dilutions. Procedure is used as per example 3 and the recovery of the regenerant as ammonium sulfate is done as given in example 4. This regeneration of the resin has given the operating capacity of the resin as 52 gm per lit. of resin
The present invention also gives the process of removal of any foulants on the adsorbent due to precipitation of hardness. The process of defouling is to pass 5 to 15 % hydrochloric acid preferably 5% at 1 to 5 BV/hr flow; preferably 1 BV flow and more preferably soaking for 1 to 8 hrs preferably 2 hrs to remove the precipitated hardness if any.
Example 8: For de-fouling; though the operating capacity drop is not significant while operation, it is desirable to give acidic water treatment to resin to remove the foulants like Fe or other metallic impurities which get trapped due to the alkaline medium of the regenerant. To reduce the effect of the entrapment of such impurities, 2 BV of 10% HC1 is passed through the resin column with the flow rate of 2 BV /hr followed by 2 BV of water wash with same flow rate. After which the capacity of the Resin is checked. The capacity of the resin found to be 1.4 meq/ml after HCL treatment where as it was 1.25 meq/ml prior to the treatment. This shows, above 93% of the capacity gain.
Example 9 : Effluent from a chemical plant was as per details given below
A) The quantity & quality of Effluent generated is as given below
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Quantity: 400 cum/day Analysis :
1) Average acidity: 3500 mg/1
2) Total dissolved solids: 3600 mg/1.
3) Average Sulfate content as CaCo3: 3500 mg/1.
4) Average COD of the effluent: 200 mg/1.
Effluent was treated with conventional method using lime to neutralize acidity. The effluent quantity and quality after conventional lime treatment is given below
1) Lime requirement average: 1500 KG/day.
2) pH of effluent after lime treatment: 7.5 to 8.0.
3) Average Quantity of lime treated effluent: 350 cum/day
4) TDS of lime treated effluent: 2700 mg/1.
5) Average sulfate content is 2500 mg/1.
6) Average COD of the effluent is 150 mg/1.
7) Lime sludge quantity: 30 cum/day having about 5% solids.
Overall dissolved solids and daily water balance with conventional lime treatment is given in sketch below




E) Quantity and quality after anionic adsorbent resin treatment:
Effluent treated by using resin and water can be recycled which has analysis as given below
l)pH: 6.5 to 7.5
2)COD: 70 to l00mg/l.
3)TDS: 100 to l20 mg/l.
4) Quantity of recycled water: 350 cum/day.
The effluent generated has average analysis as given below
1) Quantity: 20 cum/day. 2)TDS of 2700 mg/l.
3) Sulfates: 2500 mg/lit.
4) Lime sludge after filtration: 5 MT/day having about 30% of solids.
In the method of recycle of lean sulphuric acid containing effluent, regeneration of the resin is done by ammonia which in turn gives ammonium sulfate as regenerant effluent. The alternate use of this effluent is fertilizer. It can be used as is as liquid fertilizer or can be crystallized to make ammonium sulfate or can be blended with other components like potash, phosphates or urea to make require d grade of NPK fertilizer.
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We Claim ,
1. The process for treatment of lean sulfuric acid containing effluent, using Ion exchange resin comprising the steps of:
filtering the effluent using acid stable, deep bed media filtration to remove suspended solids;
passing the filtered effluent through a bed of anionic weakly basic adsorbent for removing acid by ion exchange;
passing through anionic adsorbent bed simultaneously remove organics & colors from effluent;
recovering water after removing simultaneously acid and many organics and colors from the effluent;
Backwashing adsorbent after exhaustion to remove any particulate matter;
regeneration using ammonia;
washing the adsorbent with water to remove the excess ammonia regenerant;
collecting the regenerant & wash water for recovery of ammonia;

recovering the regenerant, using alkali; preferably lime, in the form ammonia;
recovering the liberated ammonia by filtration to eliminate precipitated Calcium sulphate & washing the calcium sulfate cake with water to recover the ammonia;
or recovering the liberated ammonia by distillation to eliminate the organic eluted during regeneration & eliminate precipitated calcium sulphate by filtration; and
using the recovered ammonia for subsequent regeneration.
2. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the said anionic weakly basic adsorbent is styrenic macroporous or gel preferably macroporous with area from 15 to 35 sqm/gm; preferably 25 sqm/gm at 2 to 30 m/hr specific flow; preferably 5 to 15 m/hr flow.
3. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the said anionic weakly basic adsorbent bed has height of 600 to 1200 mm preferably 800 mm.
4. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the said regeneration using ammonia is done as 2 to 7 bed volume flow rate; preferably 2 BV/hr flow

5. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the said alkali is added to the process either by making solution or as solid in the proportion of 120% of the stoichiometric requirement of the ammonium salts.
6. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the said process maintains the resin performance in spite of precipitation of Calcium sulfate.
7. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the resin is regenerated with as low as 0.4% of the recovered ammonia.
8. The process for treatment of lean sulfuric acid containing effluent of claim 1, wherein the process enables the recycle of water.
Dated this 19th August, 2007


ABSTRACT
The process for treatment of lean sulfuric Acid containing effluent generated by processes such as sulfonation, pickling & acid catalysis by using porous Ion exchange adsorbent to simultaneously remove colors, organics and acids from the effluent making it suitable for recycle and it also regenerates the adsorbent using ammonia and recover the regenerant ammonia for reuse making process economical.

Documents:

1643-MUM-2007-ABSTRACT(28-8-2007).pdf

1643-MUM-2007-ABSTRACT(6-4-2009).pdf

1643-MUM-2007-ABSTRACT(GRANTED)-(13-1-2011).pdf

1643-mum-2007-abstract.doc

1643-mum-2007-abstract.pdf

1643-mum-2007-cancelled pages(5-8-2010).pdf

1643-MUM-2007-CANCELLED PAGES(6-4-2009).pdf

1643-MUM-2007-CLAIMS(28-8-2007).pdf

1643-MUM-2007-CLAIMS(6-4-2009).pdf

1643-MUM-2007-CLAIMS(AMENDED)-(5-8-2010).pdf

1643-mum-2007-claims(amended)-(6-4-2009).pdf

1643-mum-2007-claims(granted)-(13-1-2011).pdf

1643-mum-2007-claims.doc

1643-mum-2007-claims.pdf

1643-MUM-2007-CORRESPONDENCE 20-6-2008.pdf

1643-MUM-2007-CORRESPONDENCE(5-8-2010).pdf

1643-MUM-2007-CORRESPONDENCE(6-4-2009).pdf

1643-mum-2007-correspondence(ipo)-(14-1-2011).pdf

1643-MUM-2007-CORRESPONDENCE(IPO)-(27-1-2009).pdf

1643-mum-2007-description (complete).pdf

1643-MUM-2007-DESCRIPTION(COMPLETE)-(28-8-2007).pdf

1643-MUM-2007-DESCRIPTION(COMPLETE)-(6-4-2009).pdf

1643-mum-2007-description(granted)-(13-1-2011).pdf

1643-MUM-2007-FORM 1(28-8-2007).pdf

1643-mum-2007-form 2(6-4-2009).pdf

1643-mum-2007-form 2(granted)-(13-1-2011).pdf

1643-mum-2007-form 2(title page)-(28-8-2007).pdf

1643-MUM-2007-FORM 2(TITLE PAGE)-(6-4-2009).pdf

1643-mum-2007-form 2(title page)-(granted)-(13-1-2011).pdf

1643-MUM-2007-FORM 3(6-4-2009).pdf

1643-mum-2007-form-1.pdf

1643-mum-2007-form-18.pdf

1643-mum-2007-form-2.doc

1643-mum-2007-form-2.pdf

1643-mum-2007-form-3.pdf

1643-mum-2007-form-9.pdf

1643-MUM-2007-POWER OF ATTORNEY 20-6-2008.pdf


Patent Number 245331
Indian Patent Application Number 1643/MUM/2007
PG Journal Number 03/2011
Publication Date 21-Jan-2011
Grant Date 13-Jan-2011
Date of Filing 28-Aug-2007
Name of Patentee THERMAX LIMITED
Applicant Address THERMAX HOUSE, 4 PUNE-MUMBAI ROAD, SHIVAJINAGER, PUNE
Inventors:
# Inventor's Name Inventor's Address
1 KIRAN V. DESHPANDE THERMAX HOUSE, 4 PUNE-MUMBAI ROAD, SHIVAJINAGER, PUNE-411005
2 R.G. SHINDE THERMAX HOUSE, 4 PUNE-MUMBAI ROAD, SHIVAJINAGER, PUNE-411005,
3 S.J. NAIK THERMAX HOUSE, 4 PUNE-MUMBAI ROAD, SHIVAJINAGER, PUNE-411005
PCT International Classification Number B01D15/04
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA