The Chemical plants, particularly those manufacturing urea are amongst the most complex plants in the chemical process industry. The severe operating conditions affect the safety of equipment, personnel involved and the environment. Different occurred accidents such as Port Neal Nitrogen Fertilizer (Dec 1994), Toulouse Fertilizer complex (Sept 2001) and Coffeyville Fertilizer Plant (Oct 2010) stresses to conduct hazard studies in fertilizer plants. Urea manufacturing process is described for understanding before conducting HAZOP studies. PHA is discussed including its basics, requirements, and procedures along with techniques (HAZOP, WHAT-IF, Check List, and FMEA). The objective of this book is the identification of major malfunctions in urea synthesis section, development of systematic procedure for risk potential assessment, to identify the weak points for process improvement, to rank the potential risk scenarios and to estimate the Quantitative Risk for the worst case scenario using ALOHA software. The book will be useful for students and professionals for understanding hazard analysis techniques and its real implementation in chemical process industries.

Pakistan is facing severe natural gas crisis and all industries are suffering. Hence all efforts should be made to save natural gas from domestic use. The conventional radial flow natural gas stove burners have low thermal performance because of high convective and radiation heat losses. Swirl flow stoves have comparatively high thermal efficiency. The shape of vessel has significant effect on the performance of stoves. A swirl stove with two heating vessels (a pan and a pot) was used for experiments. Three different flame covering draft tubes were tested i.e. Ceramic mould, Aluminum draft tube and polished steel draft tube. Thermal efficiency was checked by heating water from 30 C to 80 C and determining consumption of natural gas. Ceramic mould increases thermal efficiency of swirl stove from 36 to 39.1%. The aluminum foil with ceramic mould leads to an improvement of 45.1%. Aluminum draft tube, polished steel draft tube and ceramic mould wrapped with aluminum foil showed 2.6, 3.8 and 5.6 % increase in thermal efficiency respectively. The work is useful for designing modified burners and stoves to conserve natural gas.