Pilot Plant Results Research Articles

Extraction of phenols with tert-amyl methyl ether from coking plant wastewater : Laboratory and pilot plant results

The equilibrium distribution coefficient K for mixed phenols, between coking plant wastewater and tert-amyl methyl ether (TAME), is determined. The effect of pH upon the distribution K of pure phenol is measured in the buffered water solution-phenol-TAME system. Laboratory and pilot plant results of continuous countercurrent extraction of mixed phenols from coking plant wastewater are reported.

The treatment of industrial effluents containing sodium hydroxide to enable the reuse of chemicals and water

An economically viable treatment sequence has been developed and piloted at two textile factories for the recovery and reuse of water, chemicals and heat energy from sodium hydroxide effluent produced during the scouring of cotton fibre. The treatment sequence involves pretreatment of the scour effluent by neutralisation, using an acidic gas, cross-flow microfiltration and charged membrane ultrafiltration (also called nanofiltration). The sodium hydroxide is then recovered in an electrochemical membrane cell with the simultaneous evolution of acidic gas which is recycled within the treatment process. Two possible configurations of the treatment process, where the acidic gas is either chlorine or carbon dioxide, have been discussed. Pilot plant results have been presented for both systems. The carbon dioxide system was the preferred route and is discussed in detail. The pretreatment sequence neutralised the scour effluent, lowered its chemical oxygen demand by 86% and removed 65% of both the calcium and the organics and 50% of the magnesium. The sodium hydroxide (100 to 200 g/l) and depleted brine solution (total solids 500 mg/l) from the electrochemical membrane cell were of suitable quality for reuse in the factory process. The electrochemical membrane cell produced sodium hydroxide at 62% current efficiency at an electrical power consumption of 4 000 kWh/ton 100% NaOH. The effect of electrolyte, in particular, anolyte flow rate, temperature and concentration on the limiting current density and power consumption has been investigated. Some design data for a full scale treatment plant has been presented. The operation of an acceptable background concentration closed-loop recycle wash system in the scour process was found to reduce the required membrane area by 82%. Minimum dissolution of the precious metal oxide anode coating occurred and long anode life was predicted. Serious electromembrane fouling, with increased resistance, was not apparent.

Nitrate removal from ground water

A new technique is described for nitrate removal from ground water. This technique is a combination of ion exchange and biological denitrification. Nitrate is removed by ion exchange. Regeneration of the resin in a closed circuit is achieved with a denitrification reactor. In contrast with traditional denitrification procedures there is no direct contact between ground water and denitrifying bacteria. Also brine production and regeneration salt requirements are minimal as compared with conventional regeneration of ion exchange resins. The basic design criteria and the first pilot plant results are presented. The pilot plant results show that the process is very attractive when compared with ion exchange and biological denitrification as separate techniques. Ground water with a relatively high sulfate concentration can be treated when a nitrate selective resin is used.

Laboratory and Pilot Plant Scale Development of an Alunite Flotation Process

A new flotation process to recover alunite from low-grade alunite ores is described. The process begins with run-of-mine ore, reduced to less than 5 mm (0.2 in.), being preconditioned with the reagents before grinding and alunite flotation. From the preconditioning step, ore particles, impregnated with reagents, form pellets that subsequently disintegrate into the pulp during grinding. The second step is basically a standard alunite flotation step. Pilot plant test results show that an alunite concentrate assaying at least 85% alunite and less than 5% silica can be produced. Laboratory and pilot plant results were in excellent agreement, indicating that the new process is a viable means of alunite beneficiation. Plant results, using the new process, were superior to results from conventional alunite flotation procedure.

Pilot Plant Study of the Effect of a Surface Electric Field on Fabric Filter Operation

Electrostatic fields at the fabric surface of fabric dust collectors have been observed in the laboratory to reduce the flow resistance of the collected dust and to reduce the dust penetration into the fabric. A pilot plant study of electrostatically augmented fabric filtration was undertaken to transfer the laboratory technology to the field environment. Pilot plant results are presented. These results are interpreted with respect to dust cake structure and properties.

Industrial Wastewater Treatment Using Anaerobic Fluidized Bed Reactors

Pilot plant results of anaerobic treatment using granular biological fluidized bed treatment for a number of industrial wastes is presented. Wastes containing from 5,000 to 54,000 mg/ℓ, were treated with 65 to 95 percent COD removal in 0.3 to 4.9 days hydraulic detention time. Organic loadings of 3 to 38 kg COD/m3-day were used. An energy comparison showed anaerobic treatment to produce a positive energy balance compared to an energy need for comparable activated sludge treatment.

Single Phase and Two Phase Anaerobic Stabilization in Fluidized Bed Reactors

Pilot plant studies were completed in order to derive information for process design of single and two phase anaerobic fluidized bed systems. A better effluent quality was obtained from the two phase system than from the single phase system at comparable or higher organic loading rates. A full-scale design example is presented to illustrate the implications of the pilot plant results.

U-GAS process for production of hydrogen from coal

Today, hydrogen is produced mainly from natural gas and petroleum fractions. Tomorrow, because reserves of natural gas and oil are declining while demand continues to increase, they cannot be considered available for long-term, large-scale production of hydrogen. Hydrogen obtained from coal is expected to be the lowest cost, large-scale source of hydrogen in the future. The U-GAS ® coal gasification process and its potential application to the manufacture of hydrogen are discussed. Pilot plant results, the current status of the process, and economic projections for the cost of hydrogen manufacture are presented.

Anodic corrosion protection of sulphuric acid plants with regard to the recovery of heat

AbstractAnodic protection makes it possible to keep materials which can be passivated in a “passive” state or to bring them into this state, even in unfavourable conditions.With sulphuric acid concentrations of 93–99% this method permits the use of inexpensive, stainless austenitic steels, e.g. 1.4541 and 1.4591, at temperatures of up to 160 °C. The temperature range from 120 °C to 160 °C, in particular, is suitable for heat recovery.Anodic protection by the APR‐system provides safe and low‐cost protection for air coolers and bare tube coolers in sulphuric acid plants. The results of laboratory, pilot plant and commercial trials show that in this way a safe operation of sulphuric acid coolers is possible on a long‐term basis.

Integrated Ion Exchange and Liquid-Liquid Extraction Process for the Separation of Platinum Group Metals (PGM)

Abstract A process for concentration and separation of platinum group metals (PGM) by a combination of ion exchange and liquid-liquid extraction is presented. First the PGM metals are dissolved by HC1/C11 and then passed through an isothiouronium anion exchange resin, where specific absorption occurs. The thiourea eluate from the resin is converted to the chloride complexes. Further hydrolysis (conditioning) yields an aqueous feed to a liquid-liquid extraction step, with Alamine-336. Platinum and palladium are very well extracted, while most of the other PGM are rejected in the aqueous phase. The liquid-liquid extraction can be used by itself, if the level of the base metals does not exceed the concentration of the PGM ions. Platinum and palladium are now separated from each other by the selective stripping of palladium with thiourea, and platinum with thiocyanate. The paper discusses the extraction chemistry of all the steps, and provides also experimental pilot-plant results.

Optimization of Chlorine Disinfection Efficiency

In order to show that savings in chlorine can be achieved by improved process design, parallel chlorination studies were conducted in an optimized chlorination pilot plant and each full-scale system at six different sewage treatment plants. Concurrent flow-through fish bioassays were also conducted at each location. At all test sites the optimized pilot plant used significantly lower chlorine dosages and residuals to achieve the same degree of disinfection, and its effluent was markedly less toxic than the full-scale effluents. The reasons for the good pilot plant results were variously good initial mixing, better chlorine control, plug flow contact, and better operation. Nitrified effluents required relatively high chlorine dosages for adequate disinfection. In most cases the disinfection efficiency could be expressed by the product of chlorine residual and contact time. The degree of bacterial kill obtained during initial mixing was a function of chlorine residual. Sulfur dioxide removed all chlorine-induced toxicity from the effluents.

Pilot Plant Results for Partial Oxidation of Cattle Feedlot Manure

Pilot Plant Results for Partial Oxidation of Cattle Feedlot Manure

BIVALVE MOLLUSCAN CULTURE IN AN ARTIFICIAL UPWELLING SYSTEM1

ABSTRACTSince May 1972, the St. Croix Artificial Upwelling Project has utilized a constant flow of nutrient‐rich water, pumped from 870 m depth in the sea into ponds (100 m2, one m deep) on the north shore of St. Crolx, to produce phytoplankton. This phytoplankton suspension was pumped continuously to filter‐feeding shellfish.Initial technical feasibility experiments have demonstrated that Mercenaria campechiensis, a hybrid of M. mercenaria x M. campechiensis, Tapes japonica, Ostrea edulis, Crassostrea gigas, C. gigas Kumamoto variety, Argopecten irradians and Pinctada martensii grew rapidly in this system. Crassostrea virginica and M. mercenaria did not grow well.From October 1976 until October 1978, the St. Croix Artificial Upwelling Mariculture system was operated in pilot‐plant fashion to determine yields and provide a basis for cost estimates of the system. Tapes japonica used in the pilot plant were produced in the hatchery of the Artificial Upwelling system in St. Croix. The phytoplankton protein production achieved in the pilot plant, including the down‐time of the nutrient‐limited pools for cleaning and reinoculation, was equivalent to 8.1 tons/ha/year from July 1977 until July 1978. During a 12‐month period of pilot plant operation (October 1977‐October 1978), 423 kg of Tapes japonica were produced, corresponding to 22% conversion efficiency of phytoplankton protein to shellfish meat protein and 42.3 tons of shellfish produced/year/ha of phytoplankton pond. An economic evaluation of the pilot plant results is underway.

Ozonation of Water for Salmonid Fish Rearing Facilities Pilot Plant Results

Abstract An ozone pilot plant which supplied the makeup water to an existing clarifier-biofilter recycle system was installed at a fish hatchery raising cutthroat and steelhead fry. Analysis of daily bacterial plate counts indicated that ozone consistently provided better sterilization of the makeup water than an existing ultraviolet system.

Accelerated Corrosion of Metallic and Reinforced Concrete Constructions when Connected to Lightning Conductors

With the object of examining the influence on the corrosion of metallic and reinforced concrete constructions of their connection to lightning conductors (as is demanded by the regulations of some countries), the following measurements were made: (1) corrosion potentials of steel and copper specimens (in the form of sheets) in distilled water at 25°c vs time: (2) potentiostatic curves of steel and copper specimens (in the form of sheets) in distilled water at 25° c; (3) weight loss of steel and copper specimens in the form of sheets (in ASTM corrosion chamber) and in the form of tubes (by internal circulation of artificial sea water at 70° c) and of the reinforcements of reinforced concrete specimens (in circulating sea water at 25°c). All these experiments were done with the specimens both unconnected and connected to lightning conductors (or needles); in some cases artificial lightning was introduced. These experiments proved that connecting metallic specimens and reinforcements of reinforced concrete to lightning conductors (or metallic needles) increased their corrosion rate.In subsequent papers the results of pilot plant and full scale experiments under natural conditons will be presented.

New ‘Automatic Lightning Conductor Method of Applying Cathodic Protection’ to Metallic and Reinforced Concrete Constructions: Use of Atmospheric Electricity: I. Laboratory and pre-pilot plant scale tests

In the present work, a new automatic method of applying cathodic protection, by using atmospheric electricity, is introduced. This can be achieved by connecting lightning conductors or needles to the metallic structures or the rei1tforcements of reinforced concrete constructions that are to be protected, by means of diodes allowing only the absorption of electrons.The protective properties of this arrangement were demonstrated by measuring. the corrosion potential of steel tubes in distilled water at 25°c vs time, the weight loss of steel tubes with internal circulation of 3·5% NaCl solution at 70°c in the laboratory, and also when the tubes were buried in soil out-of-doors; the weight loss of the reinforcements of reinforced concrete specimens in circulating sea water at 25°c. The measurements were made in the following conditions. with the specimens connected (or not connected) to lightning conductors in the laboratory and (in a few cases) out-of-doors, or to needles, by means of diodes allowing only the absorption of electrons. In some cases the corrosive environment was connected to lightning conductors by means of diodes allowing only the emission of electrons. In others, the last two arrangements were applied simultaneously.In subsequent parts of this work the results of pilot plant and full scale tests in natural conditions will be presented.

16—THE RAPID ACIDIFICATION OF BURRY WOOL ON A PILOT-PLANT SCALE

A description is given of a carbonizing process that has been developed up to a pilot-plant scale and shows considerable potential in eliminating wool-fibre damage and entanglement. Experimental results indicate the advantages to be gained from rapid acidification in industrial processing, and this confirms previous work on a laboratory scale. A novel rapid-acidifying machine that has been designed and developed also shows considerable potential in eliminating fibre damage and entanglement in wool-carbonizing. Previous laboratory-scale experiments indicating the advantages to be gained from rapid acidification are largely confirmed by means of the pilot plant. Some of the differences found between the laboratory and pilot-plant results are explained and the industrial implications discussed.

Dissolution of carbon steel scrap in hydrochloric acid

AbstractThe dissolution of carbon steel in hydrochloric acid has been investigated from the point of view of large scale manufacture of ferrous chloride. It has been found that the rate of dissolution at 95°c. can be represented by the equationR = k ([HCl] + 0.58 [FeCl2)0.45where k varies with the physical and chemical nature of the steel. The activation energy varies with the particular experimental conditions over the range 12.0 to 18.1 K.cal/ mole. The rate of reaction is not influenced by agitation. The mechanism of the dissolution process is discussed together with practical aspects and pilot plant results.

Copper Segregation at the Lake Shore Mine

A segregation process to concentrate ores not amenable to conventional floatation concentration or sulfuric acid leach treatment is described, and results are given for pilot-plant results over a six-month period.

Preparation of aluminum octanoate and aluminum isooctanoate

AbstractTwo aluminum soaps have been prepared as hydrocarbon gelling agents. The aluminum soap of 2‐ethylhexanoic acid (Octal) was successfully prepared by a pilot plant continuous process which utilized a flash mixer. Optimum process conditions and the effect of important process variables were determined. There was a seasonal cycle of short gelling times and low gel consistencies in the summer months and high results in the winter. The cause of the cycle is not known.Aluminum isooctanoate (Isooctal) was prepared continuously and batchwise on both a laboratory and pilot plant scale. The continuously prepared products were not satisfactory. Good Isooctals were prepared batchwise and pilot plant results were the same as those obtained in the laboratory. Gel consistencies showed a seasonal cycle but thickening rates did not.