Decarbonisation Technology May 2022 Issue



Figure 5 Solution analyses for Navy 210 unit

Operating cost

US$/long ton US$/pound

Major electricity user

Navy 1

Navy 210

0.19 0.04 0.06 0.29

Air blowers (kW) Circulation pump (kW) Belt filter (kW) Major operating cost

420 93 130 643

Air blowers (kW) Circulation pump (kW) Belt filter (kW) Total electricity (kW)

50 20 15 85

300 30 20 350

Table 3 Electrical demand

Conclusion The three Lo-Cat units at the Coso facility have been and continue to be an economical and environmentally beneficial solution for more than 25 years of continuous operation. The data show the units consistently meet H₂S specifications, with operating costs in the range of just 29 cents per pound of sulphur removed. Additionally, Navy 210 achieved significant throughput turndowns of 25-35% without adverse process effects, with only minor operational adjustments. Table 4 Operating cost per amount of sulphur removed

soil ‘amendment’. The Coso Lo-Cat sulphur has recently been certified as meeting the guidelines for use in fertilising organically grown crops. Cost of operation The two largest operating cost components of Lo-Cat units are chemicals consumption and electrical usage. Tables 3 and 4 show the current operating costs of the two units at the Coso facility. The electrical demand is constant, even with changing sulphur load. Navy 210 has a larger inventory of solution, and therefore requires more air to regenerate the catalyst. The basis for the values above is a total of 5.6 LTPD: 1.6 produced by Navy 1 and 3.9 from Navy 210. Minor costs include 2-3 hours per day of operator time to conduct solution testing and other operator tasks. Operator responsibilities include activities for other process units within the power plant in addition to the Lo-Cat unit.


David Jackson

Mark Kolar


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