No abstract

The increasing demand of current world production for hydrazine hydrate emphasizes the need to focus on the techno-economic analysis of the existing technologies. Three processes, namely the Raschig process, urea process, and peroxide-ketazine process, are chosen for technical analysis followed by cost estimation and economic assessment. The technical part involves the development of flow sheets, process design, carrying out of calculations as well as estimation of raw materials, labor, utilities, and process equipment by sizing and other sub-components. The economic part comprises the estimation of working capital, fixed capital investment, total capital investment, and total production costs. Economic parameters like net profits, rate of return, payback period, and break-even point are also estimated to perform economic analysis. The results obtained from technical analysis and economical feasibility studies show that the peroxide-ketazinebased hydrazine hydrate technology has clear advantages in terms of raw material consumption and economic competitiveness.

Hydrazine and glycerol are two widely utilized solvents in the chemical industry, which form aqueous solutions during various stages of their production or application. Distillation of these aqueous solutions is either hazardous due to the explosive nature of hydrazine or energy intensive in case of the high boiling glycerol. The focus of this study was to develop and compare alternative safe and economical methods such as Pervaporation (PV) and Membrane Distillation (MD) for separation of water from these solvents. PV experiments using the indigenously developed thin film composite (TFC) Pebax membrane revealed a high selectivity of 107 at a reasonable flux of 0.05 kg/m 2 h for a typical hydrazine hydrate feed composition of 64 wt.% N 2 H 4 . For glycerol-water mixtures, MD through a microporous, hydrophobic polytetrafluoroethylene (PTFE) membrane gave better flux (0.1 kg/m 2 h) than PV through the Pebax membrane. Interestingly, both membrane types exhibited a selectivity of infinity throughout the range of feed composition (10-90% glycerol) studied due to poor volatility of glycerol. The effect of operating parameters such as permeate pressure (0.5-10 mmHg) and feed temperature (37-100 C) on MD performance for glycerol-water separation was evaluated. The membranes were characterized by scanning electron microscopy (SEM) and sorption experiments to explain the observed results.