Douglas L. Erwin, P.E., is a practicing process engineer for engineering design and construction companies, major refinery-operating companies, and major chemical product companies. His project assignments have ranged from daily, routine technical services in refineries through the conception of new, complex, first-of-their-type patented processes. Erwin's chief quest in engineering practice has been to extend knowledge beyond commercial process simulation software, covering the severe technology gaps these packages miss. He has worked in the chemical engineering and process industry in Korea, Saudi Arabia, Indonesia, Peru, Singapore, Canada, Alaska, the United Kingdom, Europe, Africa, Egypt, and the United States. Erwin is considered by clients worldwide to be an expert on code safety practice, the design and operation of oil and gas production and gas processing plants, and refinery liquid-liquid extraction design and operation.