Sulfuric Acid Consumption Research Articles

English

  Bacterial contamination is a major problem in bio-fuel production industry; whether from molasses or corn. To improve ethanol yield at industrial scale fermentation, virginiamycin and sodium fluoride was tested. Virginiamycin gave maximum efficiency at 2 ppm and increased the alcohol level to about 1% in fermenters with the reduction of sulfuric acid consumption. By doing cost benefit analysis, it has been shown that use of this antibiotic saved a lot of money for the distillery industry.   Key words: Virginiamycin, sodium fluoride, distillery, ethanol.

A novel and cleaner technological process of extracting l-glutamic acid from fermentation broth by two-stage crystallization

The fermentative l-glutamic acid is one of the important bio-products in the world. In 2009, China produced 1.6 Mt of GA occupying more than 70% of the entire production globally. However, the problems of high sulfuric acid/liquid ammonia consumption and severe pollution in GA production process strongly limit the sustainable development of the fermentative GA industry. In this study, a novel GA extraction technology, two-stage crystallization technology (TSC), was proposed and testified in pilot scale aiming at reducing sulfuric acid/liquid ammonia consumption and wastewater pollution in GA production process. The proposed TSC process could totally recover 95% GA: extracting about 83% of GA from fermentation broth in the first-stage with isoelectric crystallization technique, and recovering more than 70% of remaining GA in isoelectric mother liquor in the second-stage with evaporative crystallization technique. With the proposed TSC process, consumption of sulfuric acid, liquid ammonia and other supplemental materials could be substantially reduced, while the amount of high concentrated wastewater decreased from 9.8 m 3/t-GA to 1.6 m 3/t-GA. Through further treatments of evaporation and centrifugation, the ammonium sulfate in the mother liquor originated from the second-stage crystallization could be recovered. The mother liquor after ammonium sulfate recovery could be consecutively concentrated into a substance in semi-molten state again, and then the substance can be manufactured as organic-inorganic compound fertilizers after quick cooling and extrusion granulating. Comparing with the existing process of isoelectric crystallization with ion exchange (IEIE), the TSC process has the advantages of high quality of GA product, less sulfuric acid/liquid ammonia consumption and no wastewater/emission gas disposals. Furthermore, the solid waste could be utilized as the value-added fertilizer at the same time. In this way, the proposed TSC process greatly promotes the economic and environmental effect of the GA production process.

Influence of Fly Ash and Silica Fume on Anti-Corrosion Characteristics of Mortar in Sulfuric Acid

A long term immersion test of mortar in sulfuric acid is carried out to investigate the effects of fly ash (FA) and silica fume (SF) on anti-corrosion characteristics. The mortar specimens have water to binder ratios (W/B) ranging from 0.5 to 0.7 and are divided into two series. Series one uses admixture of FA with replacement ratio from 0~0.3 and series two uses admixture of SF with replacement ratio from 0~0.1. The specimens are soaked in sulfuric acid with a pH value of 3.50 for 150 days. The portable pH meter is used to monitor the pH changing of the soak solution. The titrating sulfuric acid with concentration of 0.125mol/l is added to maintain the original pH value of the solution and then sulfuric acid consumption of specimens is recorded. A partial correlation analysis of experiment results shows that the effects of FA and SF on mortar resistance to sulfuric acid would change with the water binder ratio.

Extracting vanadium from stone-coal by oxygen pressure acid leaching and solvent extraction

Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction. The mineralogy of the stone-coal from Tongren City of Guizhou Province, China, was investigated by various determination methods. The effects of leaching time, leaching temperature, leaching agent concentration, leaching L/S ratio, granularity of material, additive consumption were investigated based on the mineralogy. The results show that under the conditions of leaching time of 3–4 h, temperature of 150 °C, sulfuric acid consumption of 25%–30%, ratio of liquid to solid of 1.2:1, the granularity less than 0.074 mm, additive consumption of 3%–5%, and oxygen pressure of 1.2 MPa, and the vanadium leaching rate can be more than 92% by the method of two-step pressurized acid leaching. The powdery V 2O 5 product with 99.52% in V 2O 5 content is obtained by the flowsheet of acid recovery, removing iron by reduction process, solvent extraction, precipitating vanadium with ammonium water, and pyrolysis from the stone-coal oxygen pressure acid-leaching solution. The total recovery efficiency of vanadium is above 85%, which is more than 20% higher than that obtained in the conventional process. Furthermore, the new process does not cause air pollution since no HCl or Cl 2 is released by calcination of the raw material.

Selective leaching of base metals from copper smelter slag

A novel hydrometallurgical method was developed to selectively extract base metal values, such as cobalt, zinc, and copper from copper smelter slag at atmospheric pressure. It involves leaching with sulfuric acid and sodium chlorate oxidant and neutralization with calcium hydroxide for better and faster filtration of the precipitate. It significantly decreases or avoids the adverse effects of silica and iron(III) oxides on recycling or extracting target value metals. Four key parameters were explored in this new approach, namely, sulfuric acid consumption, amount of sodium chlorate, reaction temperature and reaction time. Calcium hydroxide was one of most critical factors to precipitate silica and iron(III) oxides before filtration. Once all these four parameters were optimized, the overall extraction and recovery of cobalt, zinc and copper was 98%, 97%, and 89% respectively, while the extraction of silicon and iron was only 3.2% and 0.02%, respectively. This hydrometallurgical process, almost completely recovers the valuable metals of cobalt, copper and zinc from the copper smelting slag without roasting. The proposed leaching method is simple, economical and competitive to operate, so it is readily applicable in industry.

Caractérisation des co-produits du raffinage valorisation énergétique

A cost effective alternative to the existing treatment steps of the refining by-ptoducts, is the “on site” energetical valorization through 2 comparable technologies: thermal oxidation and anaerobic digestion combined with boiler. In a thermal multifluid oxidizer Cinclus® , the mixture is injected with atomisation and combustion air at high velocity into the oxidation chamber. The jet creates a local under-pressure and thus an internal recirculation in the oxidation chamber. This results in a controlled and homogeneous temperature and residence profile that ensure an optimal combustion with low emissions. To prevent persistent boiler fouling, the gases are cooled to below 750 °C in the gas conditioning chamber by mixing the hot gases with recycled gases taken from behind the de-dusting device. Divert investment for fossil fuel boiler and soap stock splitting to install Cinclus soap stock boiler will allow: no acid waste water, no interphase, no sulfuric acid consumption, no fossil fuel consumption. The Dranco process is a well-known and reliable anaerobic digestion technology. Its simple digester design, no moving parts within the digester, provides a high reliability and low maintenance costs. The Dranco process parameters are roughly: digester loading: 10 to 20 kg COD/m3 reactor.day. The temperature range of the thermophilic organisms is 50 to 58 °C. The retention time in the digester is about 15 to 30 days. The biogas production is above 300 m3 of biogas per ton of waste. The electricity production: above 500 kWh per ton of waste. The advantages of anaerobic digestion of waste are: The production of renewable energy and reduction of fossil CO2 -emissions ; the low odour emissions and in general low emissions towards the environment.

Comprehensive utilization of acidic wastewater from 3,3′‐dichlorobenzidine hydrochloride manufacture

AbstractIn the commercial manufacture of 3,3′‐dichlorobenzidine hydrochloride, substantial quantities of acidic industrial effluents were generated. A combination of ultrafiltration and evaporation processes was investigated for the recovery of products and dilute hydrochloric acid. In a novel purification method, waste sulfuric acid is purified and reused four or five times in the hydrazobenzene–benzidine transformation step, resulting in a 75% reduction in the consumption of sulfuric acid, minimization of wastewater discharge and environmental hazards risk and significant economic, environmental and social benefits.© 2001 Society of Chemical Industry

Modell zur Berechnung von Kapazitäten bei Bleiakkumulatoren mit festgelegtem Elektrolyten

AbstractThe discharge capacity of a lead‐acid accumulator with immobilized electrolyte is essentially limited by depletion of sulfuric acid in the porous positive electrode. A rather simple macrohomogeneous, one‐dimensional model including consumption, migration and diffusion of sulfuric acid is used to predict discharge capacities as a function of cell parameters, temperature and discharge current density. Calculated capacities agree satisfactorily with experimental data if the final voltage is approximately 350 mV lower than the initial voltage. In addition to these numerical calculations a simple analytical function to approximate discharge capacities is given. The capacity calculations can be completed by another analytical function that gives an estimate of the change of capacity when a different final voltage is applied. The model calculations facilitate the development of new lead‐acid cells designed for special requirements.

Operating experience with unit for sulfuric acid alkylation of isobutane by butylenes

The operation of units for the sulfuric acid alkylation of isobutanes by butylenes have been performed. The reaction was carried out in a KSG-3 horizontal sulfuric acid contractor. A butane-butylene fraction from catalytic cracking and an isobutane fraction from the central gas fractionating unit were used as a feedstock. The studies have shown that the unit will give a high-quality product under various conditions of operation. The specific consumption of sulfuric acid in processing different types of feed remains within acceptable limits.

Some features of spinning viscose fibre and yarns into zinc-free precipitation baths

The use of low-acid, bicomponent precipitation baths with additions of urea to the viscose, or also of baths containing such polyvalent metals as aluminum or magnesium, which permits one to obtain a fibre with improved physico-mechanical indices and fatigue properties at the spinning speeds which have been adopted in manufacturing is very promising in spinning viscose fibres and yarns into zinc-free precipitation baths. Replacement of the expensive zinc sulfate by cheaper reagents and the reduction in sulfuric acid consumption upon use of less concentrated precipitation baths permit one to obtain an economical advantage and eliminate the possibility of contaminating the water basin with toxic zinc.

Sedimentation of sulfuric acid in acid tars from current production

Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder obtained by neutralizing acid tar with a paste consisting of asphalts from deasphalting operations and slaked lime, followed by oxidation of the mixture with atmospheric air, were determined. The sulfuric acid recovered in the settling process could be burned in order to purify it of organic contaminants.

Use of a lime-sulfur precipitant for purification of wastewater from viscose manufacturing

It has been shown that it is very rational to carry out the process of cleaning up zinc-containing wastewater from the manufacture of viscose fibres by precipitating the zinc at pH 7.3–8.5 using a lime-sulfur precipitant. This will make it possible, in cleaning up 1 m3 of wastewater, to reduce the consumption of lime by 0.23 kg, the consumption of sulfuric acid by 0.25 kg, and to avoid secondary contamination of the wastewater with sulfates. The sulfur obtained as a by-product in the process of freeing exhaust discharges from viscose manufacturing from hydrogen sulfide is used for the preparation of the lime-sulfur precipitant.

Use of oxalic acid in sulfuric acid pickling

Chemical treatment of rolled products, especially the removal of scale by acid pickling, is important to improving their quality. The productivity and efficiency of acid pickling is determined by the time required to completely remove the scale, the variable costs of the operation, and the improvement achieved in the commercial appearance of the product. Operation with a closed pickling--regeneration cycle not only reduces the amount of sludge generated, but also reduces the consumption of sulfuric acid by extracting it from spent solutions.

PERSPECTIVE OF USE OF SUGAR BEET PRODUCTION WASTE - MOLASSES IN TECHNOLOGY OF RUBBER ISOLATION FROM LATEX

At present, much attention is paid to improving the production of synthetic rubbers. The introduction of new technologies to increase the productivity of the process, more fully and rationally use valuable hydrocarbon raw materials, reduce environmental pollution and improve the quality of the products is an important and urgent task. Equally important in this case is the selection of new coagulating agents used in the technology of rubber release from latex. The main requirements for coagulating agents used in the technology of rubber release from latex are: availability, low cost, non-toxicity, ease of cleaning of sewage coming to treatment facilities from them. The possibility of application of the beet-sugar production waste - molasses for beet-lean depletion - in the technology of producing butadiene-styrene rubber SKS-30 ARC has been studied. A feature of the behavior of molasses, as a coagulating agent, is shown when isolating rubber from latex. It has been established that the consumption of molasses in the isolation of butadiene-styrene rubber from latex is closely related to the consumption of acidifying agent - sulfuric acid. The higher the molasses input for coagulation, the higher the consumption of sulfuric acid to maintain the pH of the medium at the required level. The temperature of the process did not have a significant effect on the completeness of the release of rubber from latex. The extracted crumb of rubber was separated from the aqueous phase (sulfur), washed with warm softened water and dried. On the basis of the rubber obtained, rubber mixtures were prepared using standard components and vulcanized. Rubbers obtained on the basis of rubber SKS-30 ARC, in their indicators meet the requirements.

Generalization of the experiences in the operation of industrial apparatuses for the sulfuric acid alkylation of isobutane with butylenes

1. Increasing the load of the apparatuses by making use of resources of C5 and C3 fractions is considered to be undesirable without significant reworking of the apparatuses; this increases the consumption of sulfuric acid. 2. The optimum conditions of the contact and fractionation blocks of the apparatus, predicted by the design, are to be rigidly held to, particularly with respect to the reaction temperature and the number of revolutions of the turbine. 3. The preliminary preparation of the raw material should be accomplished by means of mixing the butane-butylene fraction from thermal and catalytic cracking. 4. A scheme for the consecutive connection of the contact chambers (no less than three) should be put to use. 5. A propane colume for the depropanization of the isobutane recycle should be put into use. 6. The prospective reconstruction of apparatuses is suggested in order to bring about a further decrease in the sulfuric acid consumption and to improve other indexes in the operation of the apparatuses.