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The outlook for smelter acid

Summary

Base metal smelting continues to represent a major source of sulphuric acid, with increasing demand for base metals in Asia driving new production on the one hand, and environmental concerns leading to more sulphur dioxide capture from existing smelters on the other.

Abstract

While sulphuric acid production is dominated by sulphur-burning acid capacity, base metal smelting makes up about 30% of global production of sulphuric acid. More to the point, since smelter acid is involuntary production, with its economics driven primarily by metal markets, it tends to be relatively insensitive to sulphuric acid prices, and hence is often produced regardless of prevailing acid market conditions. And while sulphur-burning acid capacity is often integrated into local downstream uses, especially phosphate fertilizer production, this is less frequently the case for smelter acid production. For these reasons, traded acid is disproportionately composed of smelter acid. Smelter acid comes predominantly (about 70%) from copper smelting, but other base metal smelting activity (zinc, lead, nickel) also contributes to smelter acid production – zinc and lead smelting represents about 20% of production and the rest (mainly nickel) the remaining 10%. These base metal industries are destined primarily for construction and industrial end uses and their consumption is closely tied into general economic and industrial growth. As a result, global copper and zinc consumption has come to be dominated by emerging Asian economies. In 2012, total global copper consumption of 20.6 million t/a was distributed as follows; 10% in North America, 14% in Western Europe and 5% in Japan, but 41% in China, and 17% in the rest of Asia. And as consumption has increased, so China in particular has turned to domestic production of key industrial metals, importing large amounts of copper concentrate from southeast Asia – amongst other places – to process in domestic smelters. The market for copper is thus a key determinant of smelter acid production. Keywords: COPPER, CHILE, ZAMBIA, NAMIBIA, INDONESIA, PERU, CONCENTRATE, PHILIPPINES

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Sulphur in the Gulf

Summary

Sulphur production continues to expand rapidly in the countries around the Arabian Gulf, from Abu Dhabi to Qatar and with new refinery production in Kuwait and Saudi Arabia, but Iraq's sulphur and phosphate mines remain a wild card in the equation.

Abstract

Processing of sour oil and gas continues to drive increased sulphur production in the countries of the Arab Gulf. This region is already one of the world’s major sulphur producing regions, and over the next few years is expected to see dramatic gains in production, balanced only partially by new demand for phosphate fertilizer production. Iraq Sulphur in Iraq currently comes mainly from refineries. There are three major refineries, at Basra, Baghdad and Bazian, as well as six smaller ones. Total installed capacity is about 840,000 bbl/d, although operating rates hover around 65-70% due to operational issues. Sulphur production averages about 250,000 t/a. Another five new refineries are planned over the next two decades, at Karbala, Maissan, Nassiriya, Kirkuk and Ninewa, and there is also expansion under way at Bazian (see Sulphur Industry News, this issue). Sulphur output from the new refineries is currently projected to total about 360,000 t/a, although the speed of new development and investment remains very much open to question. Keywords: IRAQ, IRAN, KUWAIT, QATAR, SAUDI ARABIA, REFINERY, SOUR GAS, UAE, ABU DHABI, SHAH, ADNOC, MISHRAQ.

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Hydrocarbon contamination in amine acid gas

Summary

B. Spooner and D. Engel of Sulphur Experts discuss several strategies that can be implemented by refiners and gas processing operations to mitigate hydrocarbon contamination of rich amine streams and thereby protect and enhance the efficiency of the amine units and downstream sulphur plants. The problems immediately resulting from hydrocarbon contamination of the amine acid gas being routed to the sulphur recovery unit and their effect on the plant operation and efficiency are also identified and discussed.

Abstract

Amine units are used by refiners and gas processing operations around the world to remove acid gases such as H2S and CO2 from gas and liquid streams. The H2S and CO2 are then sent to a sulphur recovery plant for further processing. Sulphur plants are designed to process acid gases, and are susceptible to damage by other hydrocarbon contamination. Excess hydrocarbons will be present in the acid gas stream from the amine unit if the amine unit is not designed or operated properly. Undesirable hydrocarbons exist in the inlet gas of most amine absorbers, in either gas or liquid phase. Either way, the amine solution can and will absorb these hydrocarbons to a certain degree. Various types of amines are somewhat soluble in hydrocarbons depending on the conditions, which explains the absorption in part. Entrainment of free hydrocarbons and emulsification of hydrocarbons in the amine solution are also possible. Keywords: amine sweetening, hydrocarbons, amine flash tanks, rich amine liquid coalescers, skimming devices.

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Turning sour casinghead gas into profits

Summary

The Thiopaq O&G bio-desulphurisation process has been successfully applied for the treatment of low pressure casinghead gas. T. Engert of Cameron and H. Wijnbelt of Shell Global Solutions International BV examine the project from initial concept through successful plant start-up and early operating history.

Abstract

An independent oil and gas operator has an oilfield in the United States containing 234 production wells. Each well generates a small amount of very rich and very sour casinghead gas which, until recently, was wasted by flaring. Taken individually, the gas from each flare does not amount to much. However, when the gas is gathered together and the H2S is treated, the value of the recoverable condensate is substantial. In addition, the local air quality is improved. The operator installed seven field compressors and 38 miles of gas gathering pipeline, pulling together nearly 1 mmscfd of gas and delivering it to a new gas processing plant using a bio-desulphurisation technology. Cameron designed and built the patented and licensed Thiopaq O&G bio-desulphurisation system to remove H2S from the gas and biologically convert it to elemental sulphur. The process is licensed to Cameron by Paqell BV of the Netherlands. Originally this process was developed by Shell Global Solutions International BV in cooperation with Paques BV. The gas gathering system and gas plant have been on-stream for several years and performing well with over 99% availability since start-up. Although proven in numerous applications, including high pressure natural gas, this was the first gas plant in the United States to use the Thiopaq O&G process to treat low pressure casinghead gas. Keywords: flaring, Paquell, casinghead gas, oxidising bacteria, MistTrap coalesce, Whirlyscrub separator, hydrocarbon liquids recovery, hydrate inhibition and stabilisation.

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A new 'zero emissions' SRU concept

Summary

KT – Kinetics Technology S.p.A. is developing a new concept for sulphur recovery units (SRUs), utilising a novel process, an innovative catalyst and a new process scheme for the treatment of all sour gas feedstocks. The core part of the innovative SRU is the sour gas Selective and Oxidative Autothermal Process (sour gas SOAP), fully integrated with the KT RAR tail gas treatment plant configuration. A distinguishing feature of the novel process is the production of hydrogen and liquid sulphur through sour gas cracking catalytic partial oxidation, instead of SO2 and liquid sulphur as in Claus SRUs.

Abstract

Environmental regulations around the world are imposing very stringent SO2 emissions requirements, H2S flaring is no longer tolerated in industrial complexes and Best Available Technique (BAT) has to be utilised to satisfy such new requirements. High reliability and availability is also mandatory for sulphur recovery units in fully integrated industrial complexes where production must be maximised. The main targets of the sulphur recovery unit in a new industrial complex can be summarised as follows: l SO2 emissions not higher than 150 mg/Nm3 (50 ppmv); l ensure complete destruction of impurities contained in the sour gas feedstock (NH3, HC, COS, CS2, RSH, HCN etc.); Keywords: KT – Kinetics Technology SpA, H2S cracking, SOAP, gas field, petroleum refinery, SO2 emissions.

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