Zim Fertiliser Maker Eyes CBM

Zimbabwe's only ammonium nitrate maker, Sable Chemical Industries, has laid out a plan to raise $200mn to build a new plant to run on coalbed methane (CBM) - but has not say how long it might be before such gas might be available. Signs are it could be the early or mid-2020s before any CBM is produced in Zimbabwe.

Ammonium nitrate is marketed mainly as a fertiliser. A preliminary stage in its manufacture is to separate hydrogen from water, using electrolysis. (That hydrogen is then reacted with nitrogen, derived from an air separation process, using heat to produce ammonia gas.)

Sable however had to shut down its electrolysis complex in Kwekwe in central Zimbabwe in October 2016 after it incurred $150mn electricity bill. Its chairman Shingai Mutasa told the country's president Emmerson Mnangagwa during a visit to its site June 6 that a new unit will be built to run on CBM, instead of grid-based electricity: "We are committed to raising more than $200mn for the CBM project."

"We switched off our electrolysis plant which was obsolete and consuming more power.  We want government support to be able to embark on this project. We will be able to produce 240,000 metric tons of ammonium nitrate annually once the project is complete. We will also be producing ammonium solution which is a key component in the production of explosives," added Mutasa.

The electrolysis plant was built in 1972 but had become too expensive to run.  It used 115MW of electricity and was Zimbabwe's single largest power consumer.  Since the unit was shut down, Sable has been importing ammonia from South Africa and operating at 40% of capacity. 

Mutasa said that Sable has already conducted a feasibility study.  When the changeover to CBM is complete, the company will produce more than 240,000 mt ammonium nitrate annually, more than the national demand of between 160,000 and 180,000 mt.  It will be running on its own power, he said, and be able to sell surplus output to the national electricity utility.

According to an earlier study conducted prior to the closure of the electrolysis unit, the switch would entail developing a gas field at Lupane in western Zimbabwe and pumping the CBM to Sable's factory 300km to the east. But Sable has not said how long that development work will take. And indications from other projects suggest it could take years.

Zimbabwe and China's Sinosteel Corp signed a $1bn agreement May 14 under which the latter will construct a 400MW CBM-fired facility to run its four chrome smelting furnaces, also in Kwekwe; but that Sinosteel CBM venture envisages full operation only by 2025.  A separate northern Zimbabwe CBM exploration scheme from an Australian investor envisages initial drilling in 2019-21.

Speaking after his tour of Sable, Mnangagwa said: "I commend the company's long term plans to use CBM or natural gas to produce ammonia gas which will be used to manufacture ammonium nitrate and urea, which will ultimately reduce the price of top dressing fertilisers."