Enhancing SRU Unit Recovery Efficiency Through Predictive Monitoring
Sandeep Sutar, Saudi Aramco
SRU plant reliability is crucial to the economic success of today’s petroleum refineries and gas processing plants. The present paper summarizes the systematic method and constant efforts that were made to enhance SRU efficiency through a predictive monitoring tool and consequently to reliability to improve plant performance. As a result, fewer plant upsets, long-term profitable and reliable operations, and consequently reductions in SOx emissions to achieve a greener environment. The paper will detail the various components considered in the predictive monitoring tool, including monitoring of: feed quality performance; catalyst performance; and unit corrosion control. In addition, the predictive monitoring tool incorporates an SRU monitoring dashboard and is supported by written procedures and operations training. By implanting and following this predictive monitoring tool, unit performance was improved significantly. For over 2 years unit availability was improved from 60% to 100, no major upset in the unit, and consequently reductions in SOx emissions to achieve a greener environment.
Low-load Claus Operation mastered by Oxygen Enrichment plus Co-Firing - Experiences from NESTE Refinery
Bernhard Schreiner, Linde AG
Jenna Dahlman, Neste
O2 enrichment for many operators plays a significant role as a means for Claus intensification for many reasons.
Historically, the primary focus for O2 enrichment was in increasing feed throughput capability. Since the late 1990’s tightening regulations on max. sulphur content in white products, refineries have had to cope with increasing H2S volumes. In addition, harsher hydrotreatment conditions (besides increasing use of conversion processes as cracking) have also generated significantly more ammonia (NH3) which typically is being sent into Claus units for disposal. Often, enhanced NH3 loads in the Claus feed are not destroyed efficiently enough within the thermal Claus section. Such lack of efficiency can lead to many negative effects, the root cause being ammonia salt precipitation in “cold” sections, thereby diminishing efficiency, reliability, economics of operation and causing corrosion.
An adequately high Claus furnace temperature is the key for efficient NH3 destruction. As the application of O2 enrichment always comes with furnace temperature increase, and today an increasing number of Claus operators apply O2 enrichment on a permanent basis for this reason, irrespective of whether a capacity increase is required.
But such O2 use – typically highly appreciated by operating personnel due to smooth plant operation - is approaching its limitation in pronounced turn-down situations; i.e. when the furnace temperature is comparably low as fuel (H2S) input is decreased considerably at constant heat loss. Here gas velocities of feed and combustion air are already low and O2 enrichment would add to this situation by even further decreasing process air flow; this in turn would move the hot flame ever nearer to the burner tip, thereby jeopardizing material integrity. Mainly due to this reason and until only recently, application of O2 enrichment was not recommended for low-load operation, and operators applied other means for temperature increase, in particular co-firing of hydrocarbons, despite this increasing the probability of soot generation, it is often applied in turn-down situations.
However, at the only Claus unit of NESTE’s Naantali site, low-level O2 enrichment recently has been involved in tackling low-load challenges and specially to increase furnace temperature with thereby decreased risk of soot generation. By combining O2 use with co-firing, an operational strategy was developed which nowadays is applied in situations of minimum feed loads around 20 percent of design. This paper offers respective case example by highlighting challenges of implementation and operational experience.
At Naantali, O2 enrichment in refining was established as a vital part of a new concept for mastering low-load operation. Accordingly, O2 use at Claus units further broadened its versatility, all-embracingly allowing for answering operational challenges ranging from extended feed load all the way down to low load situations.
An alternative way to process SWS gas. Handling ammonia in the Stoichiometry- Controlled Oxidation (SCO) unit
Arthur van Asbeck, Duiker Combustion Engineers
Processing ammonia (NH₃) rich streams is an increasing challenge in refineries and petrochemical plants. Treatment of this waste stream is crucial, as there are limited offtake options for waste NH3 from sour water, and traditional NH₃ incineration methods produce high NOx emissions that are unacceptable under increasing stringent emissions regulations. In the thermal stage of the SRU, NH₃ can be decomposed effectively provided high intensity mixing, a high operating temperature and sufficient residence time are applied. Improper decomposition will result in ammonia salt formation in downstream parts of the SRU plugging heat exchangers and increasing corrosion rates. Furthermore, the associated air demand with ammonia decomposition lowers the sulphur recovery efficiency and limits the H₂S processing capacity. This paper introduces the SCO unit, a new, robust solution to the decomposition of ammonia waste streams, whilst keeping the formation of NOx low. The unit can be utilized alongside the SRU, which enables refineries to process SWS gas outside of the SRU, eliminating potential operating problems as a result of ammonia salt formation in colder sections of the SRU.This presentation will cover the background and application of the SCO unit, and focus on SRU related application.
Conversion of Sulfuric Acid within the Claus Thermal Reactor
Christopher B. Lavery, Alberta Sulphur Research Ltd.
A novel Claus SRU configuration that integrates Haldor Topsoe’s wet gas sulfuric acid (WSA) process as a tail gas treatment technology has been developed. Through utilizing the WSA process for Claus tail gas treatment, all sulfur-containing tail gas species are recovered as H₂SO₄ and recycled to the Claus thermal reactor to become reduced to elemental sulfur. In this configuration, sulfur recoveries exceeding 99.9% can be achieved. Incidentally, the recycled H₂SO₄ serves as an O₂ carrier, allowing for increased SRU plant capacity due to a lower need for combustion air. Alberta Sulphur Research Ltd. (ASRL) undertook a laboratory investigation to examine the conversion of H₂SO₄ under a variety of thermal reactor process conditions. More specifically, the conversion of H₂SO₄ and its impact on the destruction of contaminants such as CH4, BTX and NH3 was investigated. In all cases, H2SO4 addition to the thermal reactor did not negatively influence the expected Claus chemistry nor the destruction of the contaminants present. Complete H2SO4 conversion in the off gas from the thermal reactor, was observed in all experiments, even with H₂SO₄ feed concentrations representing 10-15 % of the total sulfur input to the thermal reactor. The paper presents the laboratory setup, test programme, analyses and results from the laboratory investigation.
Intensification of sulfur processing units by oxygen enrichment and process flowsheet optimization
Attila Racz, Comprimo – Worley
To adhere to increasing emissions regulations requirements, Hyundai Oilbank decided to increase its crude oil and heavier distillate processing capacities, which resulted in a significantly higher sulfur processing requirement that cannot be fulfilled by the existing sulfur recovery plants. The refinery contains two identical sulfur recovery unit (SRU) plants, each with an amine regeneration unit (ARU), a sour water stripper unit (SWSU), and a sulfur recovery unit and tail gas treating unit (SRU-TGTU). The original sulfur processing capacity of each SRU-TGTU was 188.5 tpd, which needed to be increased to approximately 660 tpd.The paper focuses on the operational issues encountered by Hyundai Oilbank and the solutions provided by Comprimo which focused on two major options for the SRU configuration:1. Mid-level oxygen enrichment for both SRU trains, and2. High-level oxygen enrichment for one SRU train, using proprietary double-combustion technology.Additionally, optimizing the acid-gas feed composition was also investigated. The solution there considered process modifications in the ARU and SWSU which lowered the hydrocarbon content in the acid gas feeds to the SRUs.
Sulphur Recovery with COPE® Oxygen Enrichment Claus and OASE® sulfexx™ Tail Gas Treating
Thomas Chow, Fluor; Andreas Kern, BASF
Oxygen enrichment combined with amine tail gas treatment is a commonly used solution to increase the capacity of sulphur recovery units while meeting SO₂ emission objectives. Recent advances in these technologies make it possible to further lower CAPEX and OPEX while reducing the energy intensity of the operation. In this presentation, oxygen enrichment utilizing Fluor’s COPE® technology is presented with a comparison of three different tail gas treatment solvents designed for selective H₂S removal – formulated MDEA, FLEXSORB™ SE Plus, and the recently introduced OASE® sulfexx solvent developed by ExxonMobil and BASF. The economic and process advantages of the technologies are compared to MDEA over a range of conditions. In addition, the presentation will show how the combination of technologies presents a cost effective opportunity for recovering CO₂ without implementing additional costly CO₂ capture technologies.
Hidden opportunity: Maximize reliability of the waterside of Sulfur Recovery Units
Elmo Nasato, Nasato Consulting
Failure investigations, equipment design and process upgrade projects for sulfur recovery units (SRU) often overlook the impact of water quality. Recent experience with new sulfur recovery units, and process upgrades, confirm that accommodations for the different risks of today’s high-purity feedwater have not always been considered. This paper will explore impacts of higher heat transfer rates, control of boiler and condenser water chemistry, conventional equipment design/configurations and monitoring program designs. SRU operators can improve the effectiveness of their failure investigations by implementing a broader, more holistic approach that assesses equipment design, process conditions, operating protocols and water quality issues. Real world examples of SRU water-side related failures will be included in the paper and presentation.
Reliable CEMS Measurement from Sulphur Recovery Unit
David Inward, Sick AG
Emission monitoring legislation typically places specific demands on measuring & reporting emissions from the SRU. Since SRU chemistry generates unique application conditions in the flue gas stack, the SRU continuous emission monitoring system (CEMS) application is totally different to conventional CEMS applications measuring flue gases from hydrocarbon/waste combustion processes. A singular requirement for the modern SRU CEMS is to be capable of sensitively measuring ever-decreasing concentrations of target gases during typical steady-state SRU conditions but equally being able to reliably continue to operate during the vastly different conditions that infrequent process upsets create (TGTU bypass), in terms of the final stack gas composition and properties. This paper considers the technical requirements needing to be fulfilled when continuously measuring gaseous emissions from the Tail Gas Stack of the SRU. The different gas analytical technologies available are evaluated and the performance of a more recently applied analytical methodology will be evaluated based on real SRU stack gas data. Real measurement data is presented from an SRU CEMS, allowing observations & conclusions to be drawn from this experience and how this technique meets the technical and legislative requirements.
Sulfidation Corrosion in a Claus Waste Heat Boiler: A Case Study
Simon Weiland, Optimized Gas Treating Inc.
Sulfidation corrosion in Claus Waste Heat Boilers (WHB) is one of the leading causes of unexpected failures that result in unscheduled shutdowns of Sulphur Recovery Units (SRUs). Recent sulfidation corrosion measurements conducted by Alberta Sulphur Research Limited have been rolled into the kinetic and heat transfer rate-based framework of the SulphurPro® simulator to allow online prediction of sulfidation corrosion rates in operating Claus SRU’s together with the familiar Couper-Gorman curves. In the case study, simulation results for an operating unit pointed to a hidden problem that would reduce the service life to well below the original design premise. These results are presented along with general recommendations for prevention and mitigation of sulfidation potential in Claus WHB’s. This paper will present material relating to an actual operating plant and how proposed changes in operating conditions to improve unit capacity posed some potential problems to overcome.
TGTU catalyst sulphiding - Comparing field experience with published procedures
Gerald Bohme, Sulphur Experts Inc.
TGTU catalyst sulphiding can be conducted ex-situ prior to loading or in-situ as part of the TGTU startup process, but both options carry concerns regarding excessive heat generation depending on the scenario. TGTU catalyst vendors and the EPC companies that offer TGTU technologies provide written procedures for starting up either with presulphided catalyst or with oxide-form catalyst. These procedures clearly describe the steps required to ensure that the catalyst never experiences unacceptable temperature rises and also clearly describe what to expect at each stage in the startup process as well as what signs to look for as an indication of problems. Actual field experience with startup of both sulphide and oxide forms of the catalyst often provide significantly different results than what are described in the vendor and EPC written procedures. This paper will compare actual field results from a variety of operating facilities with the activation procedures commonly provided in the industry. These comparisons will cover a number of areas including: heat release during contact of presulphided catalyst with oxygen; heat release during contact of oxide-form catalyst with H2S; use of acid gas versus Claus tail gas for sulphiding; time required to sulphide catalyst at each temperature step; and overall timelines required to achieve complete sulphiding.
Temperature measurement in the sulphur recovery reaction furnace
Deniz Keles, Daily Thermetrics Corporation
The operating conditions of the SRU reaction furnace require precise temperature monitoring in order to maintain the reliability of refractory and ensure maximum sulphur recovery. Traditionally, temperature monitoring in the furnace is done either with pyrometers or special High Temperature Thermowells using a noble temperature sensor. Both options are susceptible to issues – pyrometers to errors based on sulphur build up, and Thermowells being susceptible to Hydrogen Sulfide migration which corrupts the noble metal thermocouples within. In the latter, a nitrogen purge system can be applied, but this in turn can create temperature differences, as well as additional cost and safety implications. This paper introduces a new high temperature thermowell assembly that completely eliminates the need for nitrogen purging. The design incorporates superior process protection, more accurate temperature monitoring. Operational experience will be shared in the presentation.
Successful SRU revamp with SPLITOXY
Diego Scilla, Siirtec Nigi Spa
The paper details a new oxygen enrichment technology (SplitOxy) that was applied in the revamp of an existing SRU and reports on the operational experience from the start-up. This new approach to SRU revamping for high-level oxygen enrichment, limits the reaction furnace temperature to reasonable levels while enhancing operational flexibility and control. The existing SRU consisted of a Claus unit designed for a sulphur production of 52 TPD that required about 80% increase in sulphur production, leading to a total capacity of 90 TPD. Under the exceptional circumstances the ongoing Covid-19 pandemic, the paper also describes the remote assistance provided during commissioning and start-up and how real time information was shared between refinery personnel and the licensor to deliver a successful outcome.
Amine corrosion troubleshooting within Acid Gas Enrichment Units
Inshan Mohammad, Sulfur Recovery Engineering
Corrosion in amine and gas treating units is a problem that every oil and gas refinery faces dues to the presence of acids. It is of key importance that these components are dealt with properly to ensure safe and reliable operation. This paper will look specifically at the effects of corrosion, and the associated corrosion troubleshooting methods, using examples from SRE experience. Operational experience will be shared, with a particular focus on a case study where troubleshooting was applied to perceived accelerated corrosion in AGE regenerators in a plant in North Africa.
Technical showcase: Methodologies for achieving optimized temperature profiles and stable performance in the SRU Reaction Furnace
Uday N. Parekh, Blasch Precision Ceramics
The Reaction Furnace (RF) in a Sulphur Recovery Unit (SRU) poses the greatest design and operational challenges due to its complex role both as the dominant equipment in the conversion of H2S to sulphur as well as its critical role in the processing and destruction of hydrocarbons, ammonia and Benzene, Toluene, Ethylbenzene and Xylene (BTEX) that are generally present in the process gases fed to the SRU with the specific species dependent on whether the SRU is in a refinery or a gas plant. Keen attention must be paid to the basic “3 Ts” of combustion — time, temperature and turbulence — in the SRU RF for effectively executing these roles and ensuring trouble-free downstream operation.
This paper will focus on the various methodologies that are in practice today to optimize the “3Ts” in the reaction furnace with the main focus on achieving the desired temperature for contaminant destruction, especially for lean process gases, while minimizing operating costs and loss of processing capacity. Predominant among these are fuel gas co-firing, combustion air and process gas preheating, oxygen enrichment, high intensity burners, and the deployment of appropriately configured RF internals that enhance front zone temperatures while also improving mixing and providing a tighter residence time distribution.
All the above-mentioned methods for increasing RF front zone temperature have their pros and cons in terms of their technical efficacy, capital and operating costs, maintenance implications, CO2 release and ease of operability. For example, fuel gas co-firing significantly reduces the capacity of the SRU (1 mole of natural gas adds almost 11 moles of process gas to the SRU), while oxygen enrichment has the opposite effect with the removal of significant quantities of nitrogen from the flow load but carrying the burden of higher operating costs. Burner design and RF internals are often linked, with the two having a symbiotic relationship in the calibration of the “3Ts” through the length of the RF. The paper will provide operating data from various installations as well as the results of rigorous CFD modelling to compare these various methodologies and quantify their advantages/ disadvantages for achieving optimized SRU reaction furnace performance.
Finally, there have been recent advances in the deployment of reaction furnace internals in the SRU Thermal Oxidizer / Incinerator to enhance carbon monoxide destruction while reducing energy consumption and GHG emissions and this will also be briefly presented in the paper
Technical showcase: Generating high turbulence and efficiency in thermal Claus Units despite low gas and air pressure availability
Andreas Kraxner, CS Combustion Solutions
The target of a recently executed retrofit was to replace an existing thermal Claus unit which was equipped with a kind of panel burner with more than 40 small Claus gas flames. The challenge was to replace the burner with a state of the art high turbulence burner with incinerator and waste heat boiler by keeping all process parameters – especially the pressure drop through the burner.
The available pressure drop of the Claus Gas and particularly the combustion air where relatively low compared to Claus units which were built in the last decade. Looking at the fact that turbulences in an incinerator are generated by high pressure drop it was necessary to find a solution which allows low pressure drop and this was found by using a Combustion Solutions low pressure turbulence burner combined with a Blasch Vector wall. In further alliance with Bertsch Energy GmbH & Co KG who delivered the waste heat Boiler it was possible to reach an overall pressure drop less than 100 mbar with a simultaneously very compact design. With several CFD studies and development phases it could be also confirmed that the efficiency of the thermal Unit in terms of Sulphur output is close to the theoretical conversion equilibrium of H2S to S of 70% at this particular operation temperature. It´s mandatory to find the optimize balance between residence time, temperature and turbulence (3T) in a thermal reactors.
Practical aspects of remote site support activities during the Covid pandemic
Collin Bartlett, Metso Outotec
The current pandemic has brought many disruptions in our day-to-day lives, as well as in the way industrial plants operate. This paper will focus broadly on digitalization, and more specifically how digitalisation has enabled remote site support. The authors will share experience from the last half year with the remote site support associated with various topics including installation guidance, commissioning preparation, plant start-up and plant performance monitoring. Practical experience from various plant interactions will be shared as well as illustrations of the potential upsides and downsides to these interactions.
Successful startup of a new wet sulphuric acid plant
Michiel Baerends, Fluor B.V.
This presentation covers the conception, engineering, construction and commissioning of a new sulphuric acid plant started up in a European gas processing plant. This highly complex gas processing facility processes sour gas from an off-shore field, containing sulfur, CO2 as well as nitrogen, all of which must be removed to meet transmission grid specifications. A keystone in the facility is the sulphuric acid plant, which converts H2S and mercaptans removed from the gas into sulfuric acid for export, while ensuring low emissions to the atmosphere. Troubleshooting and lessons learned from the project execution, commissioning and start-up will be shared.
Smart sustaining capital projects – Using new technology to unlock value in your plant
Boris Nesic, Chemetics
With aging assets in many parts of the globe, sustaining capital projects have become, in many cases, the cornerstone of improvements to sulphuric acid facilities for achieving the plant owners production goals. This paper will provide a set of techniques to provide a systematic methodology for reviewing sustaining capital projects from project inception to enable the available opportunities to support future performance goals via targeted debottlenecking, emissions reductions, energy efficiency improvements and/or reduced maintenance. The presentation will focus on solutions to operational problems and how modifications to plants, processes and equipment can address and eliminate operational issues. Specific case examples will be shared.
Tip the scales with the new VK38+
Mårten Nils Rickard Granroth, Haldor Topsoe
In addition to long running trends for emission reduction and higher productivity, notions of sustainability and climate footprint have gone from buzzwords to key issues that drive decisions within the industry and in the society at large. This has created an impetus for sulfuric acid plant operators to increase productivity while complying with increasingly stringent environmental regulations. This paper will present a new all-round potassium promoted catalyst that can offer significantly higher performance than a normal VK38/VK48 loading used today – the VK38+. The presentation will highlight how the catalyst can be used to address specific concerns in sulfuric acid plants. The VK38+ is already in operation in full scale sulfuric acid plants, and operational data will be presented.
A unique valve stem sealing solution to minimize fugitive emissions and extend lifetime for fluoropolymer lined ball valves
Jesse Feiler, XOMOX Corporation
Fugitive emissions are uncontrolled emissions from the process that pose a risk to the safety of employees, community, and environment. Valves are an inherent source of these fugitive emissions in chemical processing plants – in particular, commonly used ball valves. This paper will demonstrate some common issues associated with conventional ball valve designs that can leave them prone to catastrophic failure and side loading causing fugitive emissions through the stem seal. The paper will present a new stem sealing system that compensates for the side loading that can occur on the internals or externals of the valve effectively eliminating major issues found in conventional one-piece and two-piece designs.
Gas cleaning: the key to acid quality and acid plant longevity
Shailesh Chandrol, Metso Outotec
The scarcity of world class mineral resources and the degradation of head grades is leading to an inexorable increase in the impurity levels of concentrates fed to metallurgical processes. Environmental legislation, the increasing proportion of recycled materials to the process and the need for more sustainable solutions demand increased focus on the requirements and duty of the gas cleaning process solution. This article details the needs for such high-performance wet gas cleaning systems in future greenfield and brownfield upgrade projects.A critical factor in efficient removal of, for instance mercury, is the upstream wet gas conditioning and such issues will be discussed in some detail. High performance wet gas cleaning systems in the form of wet or semi-wet ventilation to control heavy metal emissions, which also places new demands on the gas cleaning process, will also be discussed.
AZFC Unit 6 Revamp: Reviving a 30-Year Old Sulphuric Acid Plant
Ayman Abd El Hafeiz, Abu Zaabal Fertilizers and Chemical Industries Co.
Jurgens Hanekom, DuPont MECS
The presentation consists of a summary of a sulphuric acid plant revamp presented both by the plant operator (Abu Zaabal Fertilizers & Chemical Industries co.) and the process engineering and technical equipment provider. The project started in July 2015, and the plant’s commissioning date was September 2016. Upon commissioning:
• The plant capacity was increased to 640MTPD compared to 480MTPD before Revamping.
• Emissions decreased from 2000mg/Am3 to < 600mg/Am3.
• Better plant availability due to less down time. Previous average = 70 days per year. Average after completion of project = 3.7 days per year
• Reduced operating cost
• Increased reliability. The plant ran for more than 3 years before the first cold shutdown after the revamp, compared to a shutdown every 4-6 months before.
The paper will share lessons learned from the project as well as details of the main components executed as part of the revamp.
Effective emissions management and reduction in sulphuric acid plants with the help of advanced catalyst types
Tom Brouwers, DuPont MECS
Catalysts are at the heart of every sulphuric acid plant. Over the past 90 years, the shape in which catalyst is supplied has evolved many times. These evolutions have been driven by operational imperatives such as the desire for faster plant start-ups and longer operational periods without shutdowns, but also the requirement to lower emissions and reduce energy consumption.
Beginning with a brief summary of historical catalyst development in the sulphuric acid industry, this presentation will address the operational challenges of reducing energy consumption and lowering emissions of sulphuric acid plants, while also aiming for longer operational periods without shutdowns. It discusses the role catalysts can play in addressing these issues, citing operational experience. The objective is to provide a greater insight into the impact of catalyst selection on SO2 emissions reduction, sulphuric acid capacity gains, energy use and extended operating periods.
A tale of two acid tower systems
Guy Cooper, NORAM Engineering & Constructors Ltd
This paper describes two recent acid tower replacement projects. The first project involved the replacement of a brick-lined tower with an alloy acid tower for a sulfur burning plant in the US south. The second project involved the replacement of brick-lined acid tower with a brick lined tower for a copper smelter in Chile. The paper describes:
• The reasons for tower replacement
• Key tower design concepts and differences
• Selection of materials: brick-lined versus alloy
• Distributor selection
• Mist eliminators
• Project execution
Corrosion and materials selection for modern sulphuric acid plants
Michael Davies, Nickel Institute
The paper will present operational experience of nickel-containing alloys in the production and use of sulphuric acid as well as the use of various stainless steels, particularly those containing silicon. As part of this it will show how these metallic alloys have solved operational problems. The presentation will summarise the major aspects of the corrosion behaviour of sulphuric acid. It will detail the effects of acid concentration, velocity, temperature, contaminants, etc. Stainless steels, particularly those with high silicon content, have become an essential part of sulphuric acid producing plants and areas of application will be discussed. Other stainless steels that are protected by anodic protection systems are widely used in cooling produced acid. Other alloys of importance, particularly in handling dilute acid will also be included. It will concentrate on the successful application of nickel-containing alloys in the production of sulphuric acid and will be partly based on the recently updated Nickel Institute publication no. 10057. The paper will also describe the use of nickel-containing and other alloys in important end use applications of this acid.
Improving acid quality on wet catalytic sulfuric acid plants
Martin Joksch, P&P Industries AG
WSA plants of whatever make and age have two limitations on the produced acid concentration, the process technology applied and the Sulphur feed quality. Even with the best technology available and the optimum waste composition, 98% Sulphuric Acid are the achievable limit.
Sometimes market or applications ask for a higher concentration or a constant percentage. In other cases the quality is not reached due to changing fuel gas composition, a worse spent acid quality charging additional water or other dubious troubles of operation.
This paper will present a new solution for WSA units to reach and stabilize their acid composition. This is achieved by applying the latest generation of special Pt promoted honeycomb catalyst. Acid polluted with organics are usable as they are cleaned by H2O2 before use. Even oleum can be produced with this small extra unit.
Small sulfuric acid plants: Viability solutions
Victor Sturm, Clark Solutions
In this paper, the Kalium operation team and Clark Solutions engineers bring an overview on compact plant technologies and an insight on recent advances that enabled viability on smaller scales. This paper also presents key conceptual distinctiveness from traditional plants.
As the first plant in Brazil to process glauconite, the Kalium Project has integrated technologies to produce commercial-grade sulfuric acid, high purity alumina, magnesium sulfate, potassium feldspar and potassium sulfate – a highly demanded and mainly imported fertilizer – with an overall cost lower than a conventional sulfuric acid plant.
This paper will detail the project and development of the plant, including sharing details of how the SAFEHR® heat recovery technology has been applied to increase steam generation to contribute to the site energy demand. From enhancements in catalyst composition and activity, increases in blower efficiency and operational flexibility to novel piping materials and breakthroughs in heat exchangers and heat transfer fluids, each aspect of technology update is briefly shown in this paper.
Technical showcase: Sulfuric Acid Plant Process Gas Dew point/Moisture Leak Detection Measurement System
Daniel Menniti, Breen
In sulfuric acid manufacturing process, SO3 gas is generally present without moisture and therefore process gas dewpoint is well below process gas temperatures and, condensation/corrosion is not present. However, there are many sections of the process where there exists a potential for moisture leakage, from the drying tower, through the final stage of conversion and economizer outlet. When there is a moisture leak of some kind, it leads to rapid downstream corrosion and early indication of such leaks is desired.
Breen has collaborated with the sulphuric acid manufacturing industry and have released a commercial instrument that will measure the process gas dew point at the converting tower economizer outlet. During this project, a process gas dew point meter was placed downstream of the converting tower economizer in three different sulfuric acid manufacturing facilities.
The meter was also placed at the waste heat boiler outlet. This paper provides updated information on the commercial installations as well as it’s real-time response to changing process conditions and moisture ingress into the process gas.
Technical showcase: Reducing NOx emissions in metallurgical oleum tower production with TWIN-PAK® Candle Filter Technology
Ali Goudarzi, CECO Environmental
Everchanging regulations and air pollution control is a major global concern, organizations are looking for smart solutions to reduce emissions to meet stipulated limits by governing bodies. Elevated temperatures required for metallurgical roasters often create higher levels of Nitrous oxide (NOx) which require abatement or exceed emission limits. As the gas flows through the operation from the roaster to the final stack output, mitigating NOx levels has become a major global initiative which has transgressed to the metallurgical sulphuric acid industry. CECO Filters in development with a major Korean metallurgical producer “Company K”, utilized the last line of defense of candle filter mist eliminators to remove NOx outputs to meet the local requirements using CECO Filters TWIN-PAK® technology and further enhance performance to meet regulations. This was developed specifically to uplifted conventional candle filter restrictions through arrangement reconfiguration by optimizing performance through increased filtration area to give additional capacity flow, reduced pressure drop, better filtration efficiency and output performance to end-users for retrofitting solutions, as well as compact design solutions for greenfield projects to reduce capital expenditures without impacting operation expenditures and maintaining an overall economical solution by optimizing the total cost of ownership for operators.
Candle Filter technology operates under wetted or partially flooded mechanisms to effectively remove sub-micron oleum mist using closely packed fibrous media in multiple density arrangements to enhance performance. CECO’s Graded BedTM technology was cleverly designed to balance the level of flooding contained within the media and create a fine oleum film layer for contact. The affiliation of absorption between sulphuric acid or oleum and NOx gases was utilized to reduce NOx concentrations in the gas stream to effective levels and compliance to local norms. As a result of the installation and added filtration area; CECO Filter’s TWIN-PAK® technology was able to remove NOx levels more effectively to 80ppm of NOX concentration to 32ppm or less, while reducing the pressure drop from 130 mmH2O (Conventional Filters) to 90 mmH2O with TWIN-PAK® filters and enhancing output levels of Oleum by higher efficiency performance.
Technical showcase: Sonic Velocity – The smart way to monitor Sulfuric Acid and Oleum
Tobias Knope, SensoTech
Sulfuric acid producers know about the problems of monitoring the quality of their product: Measurements are usually done offline by sampling what is time-consuming and in worse cases causes accidents or corrosion. Many inline measuring principles like conductivity or density are unreliable and won’t bring up clear results over the complete range of sulfuric acid.
Process monitoring with sonic velocity solves all these problems. The real-time inline measurement eliminates the need of sampling and provides accurate measuring results immediately. Sonic velocity analyzers monitor the complete range of sulfuric acid. The massive and robust sensor design ensures drift-free measurements over years. Re-adjustments or re-calibrations are not necessary.
Especially in H2SO4 applications LiquiSonic® has proven its worth for decades. This presentation shows the multiple use of sonic velocity in sulfuric acid production processes.