Economically Remove Mercaptans at the Wellhead Mercaptans represent a major challenge for oil and gas producers. Technologies to remove mercaptans have traditionally been limited and expensive, especially for the treatment of crude oil. Chevron had to clean it up at the wellhead… The crude from the Tengiz oil field in Kazakhstan is very high in mercaptans. In 1993, as part of the commercial development of the field, Chevron wanted to find a way to reduce this contaminant before pumping the crude hundreds of miles to its final destination. Chevron learned that the VNIIUS Institute in Kazan, Russia had developed expertise in the removal of mercaptans from hydrocarbon. VNIIUS and Chevron teamed up to turn the technology into a commercial reality. Chevron built a pilot plant in the United Kingdom, shipped it to its field in Tengiz and put it into operation. In 1995, the first use of the new technology was commercialized by Tengizchevroil (Chevron’s joint venture with the Kazakhstan government). Chevron and VNIIUS developed DMC-1 so that crudes could be demercaptanized before pumping them through the Russian pipeline system. Performance exceeded expectations… Since 1995, Tengizchevroil has been operating two trains with a combined capacity of 160 MBD (or, 8 million tonnes per year). While the objective was to reduce C1 andC2 mercaptans to 20 ppm, the process has been reducing the methyl and ethyl mercaptans from 260 ppm to less than 2 ppm! Two technologies available today… Since their success at Tengiz, Chevron and VNIIUS have continued to improve the technology. Today, two applications of the technology are available for removing mercaptans from sour crudes, gas condensates and LPG.

DMC-1-Technology for crude and condensates.

DMC-1 selectively treats crude oil and condensates to reduce C₁ - C₃ mercaptans content. In this process, the hydrocarbon is mixed with small amounts of air and an alkaline solution of proprietary catalysts. Mercaptans are converted to disulfides, and the hydrocarbon and alkaline phases are then separated by gravity. The demercaptanized product may then be pumped to holding tanks for storage, transportation or further processing. Variations of DMC-1 have been used in several applications, including Tengizchevroil.

Using DMC technology, Tengizchevroil has reduced methyl and ethyl mercaptans in Tengiz crude from 260 ppm to less than 2 ppm.

DMC-2-Technology for LPG and distillates.

The DMC-2 process removes the mercaptans and sulfur from LPG and distillates. Mercaptans are extracted with a caustic which is then regenerated by mixing in small amounts of air over a proprietary heterogeneous catalyst.

This technology is in commercial operation in several Russian refineries.

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DMC-1 reduces C1-C3 mercaptan content from crudes and condensates	DMC-1 reduces C1-C3 mercaptan content from crudes and condensates	DMC-2 reduces C1-C3 mercaptan content from crudes and condensates

Propak Systems Brings EP&C Expertise

In 1998, Chevron and VNIIUS signed a commercialization agreement with PROPAK to market, design, install and support the technology. PROPAK has been supplying turnkey operations to the oil and gas processing industries since 1976.

DMC technology is cost effective to install, economical to maintain and has a proven track record of safety and reliability.

For more information on PROPAK Systems and the DMC Technologies, call 1-403-912-7000.

The Partnership

Chevron is one of the ten largest petroleum companies in the world, operating in more that 85 countries through over 500 subsidiaries and affiliates. Chevron has continually developed technology to improve the efficiency of its exploration, production and refining operations.

Chevron is recognized worldwide for environmental excellence. As part of its "Protecting People and the Environment" program it continues to develop technologies which help reduce and eliminate pollutants. Chevron is pleased to be working with VNIIUS and PROPAK Systems to help reduce the content of mercaptans in hydrocarbon products.

VNIIUS is a Russian Technical Institute established in 1965 for the purpose of developing expertise in the sulfur chemistry of hydrocarbons. Located 500 miles east of Moscow, in Kazan, VNIIUS employs about 180 people. Since its founding VNIIUS has built an impressive array of technologies used in production, refining and gas processing throughout the Former Soviet Union. VNIIUS technology has successfully demercaptanized the crude and gas condensates in the Percaspian Lowlands where mercaptan sulfur content is an astounding 1% of mass. Today, VNIIUS technology is widely recognized for its efficient and effective mitigation of sulfur at any point in the production process.

PROPAK provides comprehensive engineering services to the oil and gas processing industry. The company’s mission is to design, manufacture and install cost-effective oil and gas processing equipment by combining the latest technology with experience and creativity in all phases of the project. PROPAK tailors proprietary process and mechanical designs to fit the processing requirements of its clients.

Since its inception in 1976, PROPAK has established a solid reputation for providing safe and reliable engineering and field installation of a wide range of process plants and equipment.

PROPAK, Chevron and VNIIUS look forward to future success with DMC technologies.