Energy saving complex for sulphuric acid production based on operating underground sulphur mining district

At the Yavoriv State Mining and Chemical Plant " Sirka" sulphur mining is still being carried out at the rate of 70 000 t per year by underground sulphur melting process (PVS). Remaining sulphur reserves which can be mined by PVS process constitute 8.8 mln t. 26.0 m3 of hot water with a temperature of 160 C or 4.0 Gcal is used for producing 1 t of sulphur.
Energy cost makes 70 % of the production cost of sulphur mined by PVS.
In order to considerably increase profitability of PVS sulphur mining and organize manufacturing of low cost sulphuric acid an investment project for producing sulphuric acid and commodity sulphur was developed.
Combustion of one tonne of sulphur gives 3 tonne of sulphuric acid 4 tonne of steam with such characteristics as: p=4.0 Mpa, t=440 C and hot water. Heat carrier is being prepared from the above specified steam and hot water with a temperature of 160 C at a rate of 410 m3/year for pumping down to the sulphur production boreholes. Annual sulphur production will be 130 000 t and 100 000 t of it is to be used for manufacturing 300 000 t sulphuric acid with 30000 t sulphur left as a commodity product.
Invest project basic technical and economic indices
1. Annual sulphur mining with utilization of
sulphuric acid production heat 130 000 t
2. Annual output of commodity products:
- sulphuric acid 300 000t
- commodity sulphur 30 000t
3. Capital investments 29.0 mln USD
4. Annual profit 7.0 mln USD
5. Profitability 127%
6. Payback 4 years
Taking into account considerable sulphur reserves and guaranteed sulphuric acid demand the present investment project is very attractive.
Besides, closed water circulation system at the present production facility guarantees its ecological safety.