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The importance of cryogenic distillation technologies

Summary

As the oil and gas industry focus on new requirements for CO2 recovery, cryogenic processes come under the spotlight. Mahin Rameshni and Stephen Santo of RATE USA discuss the importance of cryogenic processes in acid gas sweetening. Liquefied H2S and CO2 reinjection is proposed as a cost effective alternative to large sulphur plants.

Abstract

Cryogenics is the production and behaviour of materials at very low temperatures – the branches of engineering that involve the study of very low temperatures (ultra-low temperature i.e. below 123 K), how to produce them, and how materials behave at those temperatures. Keywords: cryogenic distillation, decarbonisation, oil and gas industry, CO2 recovery, cryogenic process, acid gas sweetening, liquefied H2S and CO2 reinjection, sulphur plant, hydrocarbon dewpoint control, NGL recovery, cryogenic nitrogen rejection, cryogenic helium recovery, SO2 liquefaction, membrane technology, RATE USA

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Advanced feed gas control by detecting BTEX in SRU feed gas

Summary

The development and implementation of modern process instruments and control systems in sulphur recovery units has increased significantly over the last decade. In this article, the impact of BTEX on sulphur plant operations and how the BTEX concentrations can be measured are discussed.

Abstract

In some hydrocarbon processing plants and refineries, benzene, toluene, ethylbenzene and xylene (BTEX), can be present in the feed gas to the Claus thermal reactor. Unlike the lighter hydrocarbons, the complete destruction of BTEX requires the reactor to operate at over 1,100°C. If BTEX destruction is not complete, soot is likely to form on the catalytic beds. For refineries this is not usually a concern as most modified Claus process units are designed to handle sour water stripper gas (SWS), which contains a percentage of ammonia (NH3). In such cases the reaction furnace temperature is kept above 1,200°C, but for natural gas processing plants it is a real concern, as the normal reactor operating temperature is below 1,000°C, making co-firing mandatory. Keywords: process control, process instruments, control systems in sulphur recovery unit, benzene, toluene, ethylbenzene, xylene, feed gas measurement, BTEX, sulphur plant operations, 2ACT Solution, AMETEK Process Instruments, Worley Comprimo

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Sulphur degassing systems for large scale sulphur recovery units

Summary

Marcus Weber of Fluor discusses degassing units for large scale sulphur recovery units, evaluating the pros and cons of various available commercial technologies with the emphasis on mega size sulphur recovery units and focussing on how technology can lower degassing capex via economy of scale for new facilities or existing facilities undergoing expansion.

Abstract

Sulphur produced in Claus sulphur recovery units (SRUs) typically contains dissolved hydrogen sulphide (H2S) and polysulphides (H2SX) in the rundown sulphur in the range of 200 to 600 ppm. This hydrogen sulphide when released from the liquid sulphur results in a concentration that can be toxic and if allowed to concentrate in closed spaces can increase to levels above the lower explosive limit and then also presents a flammability/explosive hazard. Keywords: sulphur degassing, sulphur recovery unit, large scale SRUs, H2S concentration, risk, economy of scale, new facilities, existing facilities, expansion, D’GAASS, Fluor

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Rejuvenation of a vintage SRU

Summary

In this revamp case study Scott Kafesjian and Quinn Kotter of Wood demonstrate how Wood sulphur technology was implemented at a 46-year old refinery SRU to improve reliability, operability and performance to meet new requirements for increased flexibility and higher availability.

Abstract

A recent revamp project executed by Wood was contracted by a North American refiner with two operating SRUs – SRU A, dating to 1974, and SRU B, a modular unit, designed and delivered by Wood in 2006. Each SRU included a 3-reactor Claus section, incinerator, and caustic scrubber. Having installed a NaHS (sodium hydrosulphide) unit in 2013 to treat another sour gas stream, SRU A became a non-essential unit, only maintained for safe operation, with minimal investment otherwise. Keywords: SRU revamping, revamp case study, sulphur technology, refinery SRU, increased throughput, higher availability, turnaround, refinery strategy, safety, maintenance, challenges, Wood

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60 years in the sulphuric acid industry

Summary

For six decades, Chemetics has been a pioneering force in the sulphuric acid design and equipment industry, consistently introducing groundbreaking technologies that have revolutionised the field by optimising the methodology in which chemicals are produced. This year, Chemetics celebrates its 60-year anniversary as one of the leading designers, direct equipment suppliers and fabricators that has modernised the sulphuric acid industry of today. This article dives into Chemetics' rich history and key innovations that have shaped and moulded the industry.

Abstract

Chemetics Chemetics Inc. began its journey on 2 March 1964 as Chemtech Engineering, specialising in sodium chlorate electrolysis and in the pulp and paper industry. In 1967 CIL (Canadian Industries Limited), which was majority owned by ICI of the UK and Chemetics Ltd, banded together to form a joint venture to market the chlorate technology. During this time, the experts at CIL invented the anodically protected shell and tube heat exchanger, originally known as the “CIL cooler”, which was marketed through the joint venture and that transformed the sulphuric acid industry. In September 1970, Chemech Engineering was purchased by CIL and in 1971 changed the name to Chemetics International Company Ltd. Over the next two decades, Chemetics International Ltd introduced new lines of proprietary equipment which would set the foundation and change the way sulphuric acid plants are designed today. In 1981, the company also had the foresight to purchase the fabrication facility, Fromson Heat Transfer, that had been producing the anodically protected acid coolers for Chemetics since their inception. This marked the beginning of the close cooperation between engineering and design and the fabrication that continues until today. Keywords: sulphuric acid, design, equipment, innovations, sulphuric acid industry, history, acid cooler, stainless steel converter, radial flow gas exchanger, SARAMET, drying tower, absorbing tower, acid distributor, modular equipment, gas cleaning, fabrication shop, CORE converter, Chemetics

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The merchant market for sulphuric acid

Summary

Short term supply constraints are dominating acid markets at present, but increasing smelter production across Asia may lead to oversupply in the longer term.

Abstract

The merchant market for sulphuric acid remains a relatively small slice of the overall acid market. In 2024 it is estimated to be 22.3 million t/a out of a total acid consumption of 306 million t/a. As Figure 1 shows, fertilizer production remains the largest consumer of sulphuric acid globally, driven by phosphoric acid’s use in phosphate fertilizers. Morocco, China, and India are key players, with Morocco’s OCP (Office Cherifien des Phosphates) investing heavily in sulphuric acid production to support its phosphate industry. A recovery in global phosphate demand has accelerated sulphuric acid consumption, a trend expected to continue as agricultural demands for fertilizer intensify worldwide. Keywords: battery, batteries, EV, supply, smelter, burning, pyrite, pyrites, recycle, Asia, Europe, America, Africa, Australia, concentrate, regulation, price

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The market for ammonium sulphate

Summary

Continuing growth in Chinese ammonium sulphate production is leading to a continuing flood of exports, as greater awareness of the utility of sulphur as a fertilizer leads to increasing global demand.

Abstract

Ammonium sulphate (AS) remains a popular fertilizer for its combination of nitrogen and sulphur nutrients. Indeed, the growing awareness of sulphur deficiency in soils, caused by a switch away from sulphur-containing fertilizers such as AS and single superphosphate (SSP) towards urea and mono/di-ammonium phosphate (MAP/DAP), and the reduction in deposition of sulphur on soils from sulphur dioxide pollution in the air as power plants and car exhausts become cleaner, mean that the soil nutrient sulphur requirement is growing. This in turn is leading to a resurgence in popularity for ammonium sulphate as a fertilizer and its use growing by about 3% year on year, faster than overall growth in fertilizer demand. Keywords: coke, fertilizer, China, caprolactam, LFP, supply, demand, trade, Brazil

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India's sulphur and sulphuric acid industries

Summary

India's phosphate production is using increasing volumes of sulphuric acid, but new domestic smelter and sulphur burning acid capacity may mean reduced imports in future.

Abstract

India is now the world’s fifth largest economy and the second largest country in the world by size of population, and both of these indicators continue to grow. GDP grew by 6.7% year on year for 2Q 2024, and is projected to be 7.0-7.2% for the 2024-25 fiscal year, making it one of the stars of the global economy now that China’s economic growth has stalled. As these growth rates continue, by 2030, India is projected to be the world’s third largest economy after the US and China. However, rising population – India is projected to overtake China some time in the next decade – mean that there is also rising demand for food and fertilizer. Keywords: Phosphate, Coromandel, Paradip, Paradeep, FACT, MCFL, GSFC, Iffco, CIL, coal, copper, zinc, smelter, Adani, Sterlite

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Industrial demand for sulphur dioxide

Summary

Beyond its use in the manufacture of sulphuric acid, sulphur dioxide also has many industrial uses, especially in the food, paper, pharmaceutical and refining industries.

Abstract

Sulphur dioxide, SO2, is mainly an intermediate in the sulphur industry; in sulphur-burning acid plants, it is the first step from combustion of elemental sulphur, and thereafter is further oxidised to SO3 and converted to oleum. It is also, of course, a major by-product of the roasting of sulphide ores in the metals industry, from which sulphuric acid can be produced from pyrites or copper or nickel sulphides. Keywords: food, agriculture, sulphite, water, treatment, sulphite, sulphites, refining, catalyst, SO2, paper, pulp, bleach, bleaching

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