Magazine: Sulphur

With demand for conventional fuels projected to peak and fall over the next decade, some refiners are looking to petrochemical production as a way of diversifying their product slate.

A. Goudarzi of CECO Industrial Solutions discusses the science behind NOx content and how it impacts sulphuric acid producers. In a recent project in Korea, TWIN-PAK® candle filter technology was successfully used to reduce NOx emissions in metallurgical oleum tower production. After installation of the candle filter mist eliminators the plant was compliant with environmental regulations enabling the producer to operate the plant without penalties or shutdowns.

Commodity markets are often volatile, and sulphur and sulphuric acid can be more so than most, with much of their supply coming from involuntary production, and sulphur supply in particular often dependent on the timing of large scale oil and gas projects. Even so, this year’s price rises, in some cases tripling in just over a year, have been especially eye-catching.

Production has begun at Ivanhoe Mines’ Kakula copper mine in the DRC. The company says that total production for this year is expected to be 80-95,000 t/a of copper in concentrate, with a phase two expansion to 400,000 t/a due to be completed by Q2 2022. Ivanhoe is working with China’s Zijin Mining on the development plan for phases 2 and 3 of the mine, as well as a feasibility study for the Kipushi zinc mine further to the east. Both projects lie close to the DRC’s southern border, with Angola and Zambia respectively. Phase 3 of Kamoa will lift capacity to an anticipated 600-800,000 t/a of copper in concentrate, making it the second largest copper mine in the world after Escondida in Chile. Canadian-based Ivanhoe expects to be digging 3.8 million t/a of ore at Kakula with 6% copper content in Phase 1.

The continuing spread of alkylation technology and the preference for the sulphuric acid route are leading to increased demand for acid in refineries.

Temperature monitoring and measurement of the Claus thermal reactor in sulphur recovery units is one of the most challenging applications in the oil and gas industry. Recently, market interest in unpurged thermocouples has increased with the introduction of new unpurged thermocouple designs utilising alternative thermowell materials such as monocrystalline sapphire.

The Abu Dhabi National Oil Company (ADNOC) has awarded a $510 million engineering, procurement and construction (EPC) contract to Italy’s Saipem to expand production capacity at the Shah sour gas plant, as the UAE looks to increase its output of gas by 2030. The Optimum Shah Gas Expansion (OSGE) & Gas Gathering project has been awarded by ADNOC Sour Gas, a joint venture between ADNOC and US energy major Occidental. The contract will increase gas processing capacity at the Shah plant by 13% per cent to 1.45 bcf/d from 1.28 bcf/d by 2023 and supports ADNOC’s objective of enabling gas self-sufficiency for the UAE. The Shah gas plant currently meets 12% of the UAE’s total supply of natural gas, as well as producing 5% of the world’s elemental sulphur. The expansion will cumulatively represent a 45% increase on the plant’s original capacity of 1.0 bcf/d when it came on-stream in 2015.

Sulphur ’s annual listing of new or recently completed sulphur forming projects worldwide covers both new sour gas and refinery sulphur forming projects as well as upgrades at existing units.

Significant capacity additions in the Middle East are still awaited. The more positive outlook for fuel demand is providing support to seeing these projects ramp up in the coming months. New supply is expected from Saudi Arabia following the commissioning of a gas project in 2020, sulphur availability is likely to improve from the country through the second half of 2021 and into 2022 as a result.

Are the three “T”s (temperature, turbulence, time) of Claus unit ammonia destruction still meaningful with improved understanding of the thermal reactor? CFD models appear to be adequate at higher temperatures, e.g. 1,200°C, but not at lower temperatures, e.g. 800°C and 1,000°C. A. Keller, on behalf of the Amine Best Practices Group, reviews how meaningful the rules of thumb for Claus unit ammonia destruction really are.