From Solar Hydrogen to Desert Development: A Challenging Approach

Abstract

This paper presents a novel approach for desert development, taking the Arab countries a model in our study. Solutions to make the most from the sun to turn our desert into useful and arable land are proposed. Saline water resources from sea or rejects from desalination plants (brines) are chemically processed to produce partially desalted water along with valuable chemical products. Solar hydrogen is a cornerstone in our system to produce ammonia, which has dual functions in the scheme. Ammonia represents a source of nitrogen for plants. It is used together with carbon dioxide in the chemical separation process of saline water. For the Arab countries with an average solar intensity flux = 700 Watt/m 2 , an average sunshine hours of 3000 annually and only 1% of total land area for solar power generation, it is feasible to produce the equivalent of 184 × 106 tons of hydrogen yearly by water electrolysis. Ammonia gas synthesis takes place, using solar hydrogen and atmospheric nitrogen. Experimental findings are reported by the author and co-workers. Separation of salt brine (from inland sources or from the sea) was carried out in a gas bubbler using a modified Solvay process to study the conversion of sodium chloride into chemical products (namely sodium carbonate and ammonium chloride). The highest conversion achieved of sodium chloride was 82.2%, and the balance makes partially desalted water. Magnesium chloride is obtained as a by-product. The role of hydrogen as a vector coupled with solar energy for desert development is schematically illustrated.