Sulphuric Acid Plant Research Articles

M.C. Mehta And Anr vs. Union of India & Ors.

The privately held Shriram Food and Fertilizers Ltd. fertilizer factory was situated in Kirti Nagar, a densely populated district of Delhi with a population of about 200,000. Due to the factory's chemical operations, it released dangerous compounds that annoyed the population. On December 4 and 6, 1985, public interest lawyer MC Mehta submitted a writ petition to the Supreme Court under Articles 21 and 32, requesting the closure and transfer of the factory's Shriram Caustic Chlorine and Sulphuric Acid Plant. During the pending lawsuit, the Oleum Gas Leak incident occurred at one of the factory's plants and caused severe harm to people who inhaled the gas. The leakage also took the life of one of the lawyers who practiced in the Tis Hazari Court.

Application of sulphate and magnesium enriched waste rapeseed cake biochar for recovery of Cu(II) and Zn(II) from industrial wastewater generated in sulphuric acid plants

The development of an efficient and green adsorbent is of great significance for copper(II) and zinc(II) removal and recovery from industrial wastewater. In this study, for the first time, waste rapeseed cake is used as a biosource to synthesize MgO-SO3 enriched biochar. The newly developed adsorbent was produced in a one-step process by pyrolysis at 973.15 K for 2 h, under anoxic conditions. Porous structure, specific surface area, and composition of biochar were studied. Furthermore, sorption properties of the obtained biochar in relation to copper(II), zinc(II), and arsenic(III) ions were also studied. The impact of parameters such as: sorption time, temperature, adsorbate concentration, sorbent mass, and solution pH on the efficiency of the adsorption process of the studied cations was examined. Rapeseed cake biochar exhibits good Cu(II) adsorption capacity (90.4 mg g−1) with a short equilibrium time (4 h), which indicates the competitiveness to similar adsorbents. The adsorption of Cu(II) on the biochar was more consistent with the pseudo-second-order kinetic models and Langmuir model. The Freundlich and pseudo-second-order kinetic models best fitted the removal of Zn(II) by modified biochar. The mechanism of Cu(II) and Zn(II) adsorption was also postulated. Experimental data collected have shown that the presence of arsenic(III) at higher concentrations adversely affects the sorption efficiency of Cu(II) and Zn(II) ions. Thus, this study shows that the sorbent can be successfully used for the separation of Cu(II) and Zn(II) from technological wastewaters. A flowsheet for the proposed process is presented.

A case study comparison of a sulphuric acid plant with and without on-site low-grade heat recovery and repurposing

A case study comparison of a sulphuric acid plant with and without on-site low-grade heat recovery and repurposing

A detailed reaction mechanism for elemental sulphur combustion in the furnace of sulphuric acid plants

AbstractElemental sulphur combustion is traditionally used to generate SO2 to produce sulphuric acid that is consumed in chemical industries, but is now also being considered as an energy vector for power generation. Despite the fact that sulphur combustion has been practiced for decades, there are limited reaction mechanisms for its combustion chemistry, which is critical for the optimization of the sulphuric acid production process to maximize efficiency and reduce cost. In this paper, a detailed reaction mechanism is developed and validated with different sets of experimental data from lab‐scale and industrial plant studies. The reaction mechanism is used to conduct sulphur furnace simulations, where the effects of feed air/sulphur ratio and oxygen enrichment of air stream on furnace temperature and the concentrations of SO2, SO3, and O2 are investigated. The dominant reaction pathways in sulphur combustion, particularly for the production of SO2 and SO3, are identified. It was found that the feed air/sulphur ratio monitors the furnace temperature and can be used to obtain the desired O2/SO2 ratio at the furnace exit for the optimal operation of catalytic converter (for SO2 oxidation to SO3) that follows the furnace in the sulphuric acid plant. Moreover, high oxygen enrichment above 35% (while maintaining the desired O2/SO2 ratio at the furnace exit) significantly increased the furnace capacity through reduced total gas flow (thus decreasing blower energy requirement and equipment size). The developed reaction mechanism provides a method to obtain optimized furnace parameters to achieve high efficiency and reduced costs in sulphuric acid plants.

Behaviour of lead and selenium during sequential sodium carbonate and nitric acid leaching of slime generated by the sulphuric acid plant of the Balkhash copper smelter

This paper examines the process of selenium precipitation from the slime generated by the sulphuric acid plant of the Balkhash Copper Smelter. Contrary to similar tailings generated by non-ferrous metals industry, such slime has a high concentration of selenium (12.5–4.6 wt. %). By utilizing it in the production process, one can raise the output of selenium by more than 30% compared with the amount of selenium recovered by the smelter from copper anode slimes. The slime that was used in the experiments had been separated from the slurry produced as a result of scrubbing of metallurgical gases generated by copper smelting and matte converting processes. The slime was rinsed with water to remove sulphuric acid from it and then dried at 105 oC. With the help of new-generation analytical equipment, the slime was analyzed for qualitative, quantitative and material compositions. 15 elements with significantly varying concentrations were detected. The main components include lead (51.17 wt. %) and selenium (12.49 wt. %), which are present in the form of lead sulphates and elemental selenium. Other lead and mercury compounds are also present as disseminations – i.e. different salts of selenium acids. Considering the forms in which lead and selenium are mainly found in the slime, lead was initially converted into carbonates by sodium carbonate leaching, and then nitric acid was used to make lead transfer from the cake into the solution. The authors looked at the effect produced by the sodium carbonate concentration (50–200 g/dm3), solid-to-liquid ratio (1:(2–6)), process duration (20–120 min) and temperature (20–70 oC) at constant slime feed and stirrer RPM on the behaviour of lead and selenium. Optimum conditions were identified in which both elements almost completely remain in the carbonate cake, and only 0.019% Pb and 0.17% Se get extracted into the solution. Different quantities of three carbonate-containing compounds of lead and seven selenium compounds were found in the cake. When the carbonate cake is leached with nitric acid, almost all of the lead transfer to the solution, while selenium remains in the cake as an elementary substance and mercury selenides. As compared with the slime, the concentration of selenium in the cake increased by 5.6 times. This research was funded by the Science Board of the Ministry of Science and Education of the Republic of Kazakhstan under the following programme: Development and Implementation of Innovative Technology Ensuring a Higher Recovery of Non-Ferrous, Noble, Rare and Rare Earth Metals, as well as Fulfillment of Production Targets by Industrial Companies of the Republic of Kazakhstan Set for 2018–2020.

Forecasting mass and metallurgical balance at a gold processing plant using modern multivariate statistics

Knowing the quantity and the quality of products and tailings generated by a beneficiation plant, even before ore processing, can make the mining operations more sustainable, more profitable, and safer. To forecast these values, it is necessary to submit samples to batch tests which mimic the processing workflow used on an industrial scale. Then, the results need to be analysed with the aim of finding a statistical model able to comprehend how Run of Mine (ROM) characteristics impact the performance at the beneficiation. After developing a model, it is possible to apply it to blocks where the ROM characteristics are known, but the metallurgical information is not, making it possible to estimate these. With this goal, a geometallurgical model was developed with a neural network technique using 37 samples collected at two Brazilian gold mines. The Au and S grades in ROM, and the mine from where the sample was collected, were used as input variables. The model was able to forecast the following variables with a Pearson correlation coefficient on the cross validation test set equal to the value in parenthesis: mass (0.55) and metallurgical (0.54) recovery in the gravimetric concentrate, mass (0.80) and metallurgical (0.12) recovery in the flotation tailings, mass (0.77) and metallurgical (0.11) recovery in the leaching tailings, mass recovery (0.84) of gas sent to the sulphuric acid plant, and metallurgical recovery (0.65) in the leaching concentrate. The results obtained with neural networks were superior to the ones obtained when three alternative techniques were tested.

Dynamic modelling and simulation of the sulphur dioxide converter in an industrial smelter

AbstractSulphuric acid plants have been widely used in industrial smelters to reduce sulphur dioxide () emissions to the atmosphere. The catalytic converter, where is oxidized to sulphur trioxide (), is the key unit and determines the performance of a sulphuric acid plant. In this paper, a dynamic model is built based on mass and energy conservation for the converter in an industrial smelter. The derived model is compared with industrial measurement and a very good fit is obtained. A key variable of high industrial interest, conversion ratio, is defined and explored in modelling the converter, and thus the resulting model is of important industrial values. Based on the derived model, simulations are run to investigate the system dynamics and effects of process variables.

Enhanced Recycling of Waste Copper Smelter Dust from Existing and Proposed Smelter Plant at the Palabora Copper (pty) ltd, impopo, South Africa

The whole facilities at the Palabora Copper (PTY) Ltd (PC), Limpopo, South Africa (i.e. both existing and new) are under obligation to comply with the new plant MES by the 1st of April, 2020. At the moment all processes on the PC mine conform to the MES for existing plant with the exception of the copper smelter and the associated sulphuric acid plant. Despite considerable investment by PC over the last few years in equipment and maintenance, due to the short comings of the copper smelting technology employed on site, certain relevant MES have proven to currently be unachievable. The generation of the waste CSD is considered a global issue and at PC the direct smelting process option is the recycling method currently being used to manage the generated waste CSD at the copper smelting plant. This recycling method is neither cost effective nor energy efficient and it leads to the production of worthless residues. As a result, an enhanced hydrometallurgical based recycling process option is recommended as an appropriate recycling process option. Hence, it was concluded that an industrial scale centrifugal separator like the Knelson or Falcon concentrators be stationed in the existing and proposed plants as a separate but integral part of the ore processing system, so as to reduced/removed the reactive materials it often contains before subjecting it to a hydrometallurgical and Nano technological processing, in order to recover the copper value in it as precipitates of nanoparticles.

Multi-objective optimisation of a double contact double absorption sulphuric acid plant for cleaner operation

Abstract The release of oxides of sulphur (SOx) and acid mist (H2SO4) during the production of sulphuric acid in the double contact double absorption (DCDA) process is hazardous to the environment. It is a challenging task to minimise these emissions while keeping plant operation within the production requirements and maximise revenue. In this study, SOx emissions, acid mist emissions, and net revenue are considered as objectives for multi-objective optimisation (MOO) of the DCDA process. Firstly, the process is modelled and simulated in Aspen HYSYS, and validated with plant data. MOO is then performed using the elitist non-dominated sorting genetic algorithm to predict sets of Pareto-optimal operating conditions for improved environmental and economic performance. The effect of operating parameters such as air flow rate and pressure, inlet temperatures to catalytic beds and absorbers, demineralized water flow rate, and boiler feed water flow rate on the process performance is also studied. The results show that the DCDA process can be operated at different optimal conditions, each of which involves some trade-off among the objectives of interest. A multi-criteria decision-making technique (known as technique for order of preference by similarity to ideal solution, TOPSIS) is used to determine the most suitable optimum operating point. Among the optimal conditions, the chosen solution through TOPSIS has 9.5 ppm of SOx emissions, 70.9 ppm of acid mist emission and 143.0 M$/y of net revenue (i.e., gross profit). The air flow rate strongly influences the objectives in opposite direction; at the selected optimum solution, it provides improved environmental and economic performance within acceptable limits of product quality.

Issue Highlights

The Canadian Journal of Chemical EngineeringVolume 95, Issue 6 p. 1022-1022 Issue HighlightsFree Access Issue Highlights First published: 21 April 2017 https://doi.org/10.1002/cjce.22849AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat 1023 Benchmarking the Timmins Process - A Novel Approach for Low Energy Pre-Combustion Carbon Capture in IGCC Flowsheets Bart Hallmark, Julian Parra-Garrido, Andrew Murdoch, Ian Salmon and Chris Hodrien The Timmins Process is a novel pre-combustion carbon capture process that combines industrially-tested unit operations in a novel and unique configuration, with the aim of providing high levels of carbon capture with minimal energy penalty. This paper reports an initial benchmarking study of this process in the context of an IGCC flowsheet, and concludes that the net efficiency of the plant incorporating the Timmins Process varies between 33.8 % and 34.3 % at a carbon capture level of 91.8 % (on a mass basis) depending on the process configuration and the cooling water temperature.1 1093 A Soft Sensor for the Sulphur Dioxide Converter in an Industrial Smelter Jianjun He, Junfeng Zhang and Helen Shang A catalytic reactor that converts sulphur dioxide to sulphur trioxide is a key operation in a sulphuric acid plant. The sulphur dioxide conversion ratio represents an important performance indicator for a sulphur dioxide converter. In this paper, a soft sensor is developed for the sulphur dioxide conversion ratio and outlet concentration. The soft sensor is built based on the steady state mass balance model of the converter and industrial dynamic data analysis. It provides a real-time estimate of the unmeasured variables from available industrial real-time measurement.2 1171 Modelling of Dynamic Mass Transfer in a Vapour Extraction Heavy Oil Recovery Process Qiong Wang, Xinfeng Jia and Zhangxin Chen This study presents a new method to determine the effective diffusivity between a vaporized solvent and a crude heavy oil in a vapour extraction heavy oil recovery process. It is found that both constant and variable diffusivities can achieve a satisfactory match in cumulative oil production data, but the latter gives more accurate characterization of transition zone properties. Some correlations are also regressed to convert a constant diffusivity to an equivalent variable diffusivity. Moreover, back-calculated constant effective diffusivity is found to be about 10–30 times of the corresponding molecular diffusivity measured in the laboratory.3 References 1 B. Hallmark, J. Parra-Garrido, A. Murdoch, I. Salmon, C. Hodrien, Can. J. Chem. Eng. 2017, 95, 1023. 2 J. He, J. Zhang, H. Shang, Can. J. Chem. Eng. 2017, 95, 1093. 3 Q. Wang, X. Jia, Z. Chen, Can. J. Chem. Eng. 2017, 95, 1171. Volume95, Issue6June 2017Pages 1022-1022 ReferencesRelatedInformation

Using heat pipe to make isotherm condition in catalytic converters of sulfuric acid plants

In this study, for the first time, it is tried to construct a pilot reactor, for surveying the possibility of creating isothermal condition in the catalytic convertors where SO2 is converted to SO3 in the sulfuric acid plants by heat pipe. The thermodynamic and thermo-kinetic conditions were considered the same as the sulfuric acid plants converters. Also, influence of SO2 gas flow rate on isothermal condition, has been studied. A thermo-siphon type heat pipe contains the sulfur + 5% iodine as working fluid, was used for disposing the heat of reaction from catalytic bed. Our results show that due to very high energy-efficiency, isothermal and passive heat transfer mechanism of heat pipe, it is possible to reach more than 95% conversion in one isothermal catalytic bed. As the results, heat pipe can be used as a certain piece of equipment to create isothermal condition in catalytic convertors of sulphuric acid plants. With this work a major evaluation in design of sulphuric acid plants can be taken place.

A soft sensor for the sulphur dioxide converter in an industrial smelter

In metal productions from sulphide ores, sulphur dioxide (SO2) is generated when the ore concentrate is smelted. To minimize emission of SO2 to the atmosphere, sulphuric acid plants are used to convert SO2 gas into sulphuric acid product in smelters. A SO2 to sulphur dioxide (SO3) converter, where SO2 is oxidized to SO3 with the help of catalyst, is the key unit in a sulphuric acid plant. For monitoring the converter, temperature of the reactor is extensively measured at various locations, but the concentration of SO2 is barely measured or only measured at very limited points due to the difficulty and costs involved. In this paper, a soft sensor is developed to estimate the conversion ratio and concentration of SO2. The soft sensor is derived based on the steady state mass balance model of the converter and dynamic data analysis. From the proposed soft sensor, conversion ratio and concentration of SO2 can be estimated from available industrial real‐time measurement.

An example of the use of advanced fibre-reinforced plastics in sulphuric acid plants

An example of the use of advanced fibre-reinforced plastics in sulphuric acid plants

Two years of operation at Kansanshi's sulphuric acid plant

Two years of operation at Kansanshi's sulphuric acid plant

Sulphuric acid plant optimization and troubleshooting

Sulphuric acid plant optimization and troubleshooting

Copper and cobalt recovery from pyrite ashes of a sulphuric acid plant.

The pyrite ashes formed as waste material during the calcination of concentrated pyrite ore used for producing sulphuric acid not only has a high iron content but also contains economically valuable metals. These wastes, which are currently landfilled or dumped into the sea, cause serious land and environmental pollution problems owing to the release of acids and toxic substances. In this study, physical (sulphation roasting) and hydrometallurgical methods were evaluated for their efficacy to recover non-iron metals with a high content in the pyrite ashes and to prevent pollution thereby. The preliminary enrichment tests performed via sulphation roasting were conducted at different roasting temperatures and with different acid amounts. The leaching tests investigated the impact of the variables, including different solvents, acid concentrations and leach temperatures on the copper and cobalt leaching efficiency. The experimental studies indicated that the pre-enrichment via sulphation roasting method has an effect on the leaching efficiencies of copper and cobalt, and that approximate recoveries of 80% copper and 70% cobalt were achieved in the H2O2-added H2SO4 leaching tests.

Convertible Lump Sum EPS Contracting Model – How to Get the Plant you Need Now and Still Enjoy in 20 Years?

In most instances process plants are designed to meet performance objectives that are clearly defined by a detailed technical specification. The contractors and licensors designing and building such process plants are quite proficient at designing a plant to meet those performance values for an economically attractive cost. However the reality for the owner and operator of the plant is that over the 40+ year lifetime of the plant the inlet feeds, production rate and operationally desired set points for each piece of equipment will change. Often times this can result in a non-optimal plant and performance problems or poor reliability. This fact is particularly severe for plants which undergo significant corrosion or fouling like that commonly seen in sulphuric acid plants. Plants are built to make money for their owners. The primary way to make the most money out of a facility is to have the plant operational at as high of a capacity as possible for the maximum number of days in the operational life of the plant. There are numerous ways that the plant designer and builder can place design allowances, safety factors, built in redundancy, optional operational configurations, bypasses and other tricks to allow the facility to operate well for all desired production rates and all desired feed types. The costs of such options are often quite small if dealt with in the initial design phase. Unfortunately, in nearly all instances this optimal facility is not the facility that is built for the client. The reason why is often the inflexibility in the client/designer contractual relationship prevents open discussions on optimization. The Convertible Lump Sum EPS model can be used to get the optimal plant design for the client's present and future needs as well as providing price surety of a lump sum execution.This paper will detail the aspects of the Convertible Lump Sum EPS model. It will use an example sulphuric acid plant project to show how the client can be involved in the decision making process to get the best plant design for their site with appropriate design factors and options. Instances will be illustrated where plants have been built that do not have the flexibility required to operate effectively as the plant ages and/or the plant slightly changes operational modes. This lack of flexibility often causes damage to the plant and operational downtime or reduced capacity. Cost/Benefit analyses will be done on each of these cases. This paper will show that use of an effective, technically and commercially transparent contracting model with the appropriate partner can allow significant savings in TIC cost as well as for total return on investment.

Process Heat Recovery and Digitalisation in Sulphuric Acid Plants

Energy efficient processes with maximised heat recovery and efficient operation have moved more and more into focus in the sulphuric acid business. Even metallurgical plants are now expected to produce high pressure steam for power generation. With the help of proven processes, like the Outotec LURECTM, HEROSTM and HIPROSTM technologies this demand can easily be satisfied. Heat recovery causes interconnections between different areas of a complex to become more common. Additionally, individual plants have increased in complexity, which both leads to higher requirements for operational personnel. The unfortunate combination of higher personnel mobility and fluctuation with remote locations of green or brown field sulphuric acid plant projects results in often less experienced personnel, who need support to operate today's state of the art sulphuric acid plant. By combining Outotec's process knowledge with actual operational data of the plant, a digitalisation system can greatly assist operation.The combination of higher efficiency and assistance through digitalisation will be further detailed in the Outotec presentation.

Revamp and Upgrade Possibilities in Sulphuric Acid Plants

This paper will elaborate on the possibilities and influencing factors for revamp and upgrade projects for sulphuric acid plants and OUTOTECs possible contribution to a successful execution of such projects.Main drivers to execute revamp project will be discussed: e.g. changing environmental requirements, increased demand for acid production, increased demand for energy production as byproduct or changes in production profile. Other aspects might target lower operating costs, better availability or longer operating periods between shutdowns. Finally, worn-out equipment must be replaced and decision must be taken either to go like-for-like or to use the chance to combine the replacement with an upgrade to more developed solutions.The paper will also cover the various aspects and influencing factors, which contribute to the decision making in a revamp project. Such aspects might be budget or schedule restrictions as well as restricted resources for labour and material at site during the execution of the project.OUTOTEC will present its portfolio of possible services covering engineering, procurement, construction, commissioning as well as operating and maintenance support, spare parts business or operator training. Depending on the project setup the split of scope and responsibilities has to be carefully chosen and agreed between the involved parties to obtain the optimum result.The presentation will provide examples of executed revamp and modernization projects of the recent past.

Aspen Simulation of Heat Exchange Network for the Conversion System of Sulphuric Acid Made with the Sulphur

This paper takes the conversion system of sulphuric acid plant made with the sulphur as research object, utilizes Aspen Plus process simulation software to carry out steady state process simulate for the conversion process, and obtains physical property data of all the process streams; utilizing Aspen Energy Analyzer software, that the minimum heat transfer temperature difference (ΔTmin) determined is 10 °C, the temperature-enthalpy composite curve and the pinch temperatures of hot and cold streams are got under the ΔTmin, the energy consumption of heating utilities reaches zero, and cooling utilities use 45 °C of desalted water. Simulating for heat exchange network with pinch technology and Simulating the matching design of heat exchange network with Aspen Energy Analyzer software, the heat exchange effect is basically as same as the heat exchange network in actual production.