Principal Technology Inc, a provider of total system solutions for natural gas, refining, chemical, process and manufacturing facilities, has introduced a tail gas diverter valve system that it claims out-performs other designs.

Leading the sulphur recovery industry in the development of high-performance tail gas diverter valve systems, Principal Technology uses components selected specifically for tail gas service that have proved to be reliable in scores of installations spanning more than 30 years. It meets the industry’s need for specially designed tail gas diverter valve systems that provide exceptional performance, functionality and reliability.

“Principal Technology designed its tail gas diverter valve system to address the crucial need to keep elemental sulphur molten during the process of removing it from natural gas or refined petroleum products,” said its president and CEO Matthew S Hodson.

“Solidified or ‘freezing’ sulphur is the primary cause of unreliable operation of tail gas diverter valves because elemental sulphur tends to condense and collect on the inside of the pipe, packing and bearing surfaces in the SRU tail gas piping.”

The valve must also seal tightly to prevent sulphur compounds from leaking into the downstream equipment. Leakage into the incinerator can cause unexpected environmental emissions and leaks into the tail gas unit can cause safety or corrosion problems. The company’s system addresses all of these issues and more.

Because it is critical that SRU tail gas valves be maintained at a temperature greater than 280 F to prevent elemental sulphur from freezing, Principal Technology’s tail gas diverter valve operates properly up to a temperature of 500 F. The design includes the use of laminated graphite packing and a special disc seal system that meets ANSI Class VI shutoff criteria. The valve body is completely steam jacketed to maintain the entire body, shaft, disc and seal at a temperature between 280 and 300 F. The welded jacket is integrated with the body and the steam and condensate connections are located so as to ensure complete distribution of the steam around the valve body and the sensitive shaft bearing blocks.

An important accessory feature available is real time temperature monitoring of the valve body internals. Principal Technology developed techniques for measuring the valve body temperature through finite element analysis and thermal modeling. By continuously monitoring the internal body temperature, plant operators can ensure that liquid sulphur will not solidify, causing the valve to freeze in position. The temperature monitoring system measures the temperature at a critical point in the body and reports to unit operators if the temperature goes outside pre-set parameters.