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Work on Responsible Care goals progressing at Synfuels Plant

Responsible Care goals set for 2011 demonstrate a willingness that Dakota Gas works to improve safety for its employees.

Basin Electric Power Cooperative - July 1, 2011

Dakota Gasification Company publishes a Responsible Care Performance Report every year, identifying goals in the areas of safety, security, environmental compliance, sustainability and product stewardship. For the full report: Dakota Gas Responsible Care

Following is an update on goal progress this year:

Goal: Develop a system to minimize employee exposure to hazards associated with plugged waste heat exchanger sumps in gasification. Assigned to process operations.

Update: Montine Swikert, section engineer, said they are continuing to expand the use of the waste heat exchanger (WHE) grinders now that leakage issues on Charlie gasifier were resolved with Atlantic Coast Crushers. Since the grinder was installed on Charlie gasifier, only one plugged sump was noted. During the first maintenance turnaround, grinders were installed on Albert and Dave gasifiers. During the second train turnaround, maintenance completed piping modifications on seven additional gasifiers and inserted piping spool pieces where the new grinders will be installed.

The API trench closure project completed in 2010’s turnaround resulted in a noticeable decrease in WHE blowdown fumes that previously would backflow into the gasification building. However, since the API trench closure, the building envelop has become too tight, creating a buildup of carbon monoxide in the building. Plant engineering is considering a louver system with heating coils to address this issue.

Two other projects to minimize plugged WHE sumps are ongoing. A new valve design is being tested on one of the gasifiers with a slightly larger clearance path through the valve trim. The valve trim is also constructed out of tungsten carbide to last longer as opposed to our current 440 SS trim valves. This project will be implemented this summer. Plans to look at the gasifiers’ grate drive operation and test different control schemes to see if the current grate operation control system is also causing high gas outlet temperatures and plugged WHE sumps will also continue this summer.

Goal: Implement improvements to reduce the number of bolted joint leaks. Assigned to maintenance.

Update: During the recent half-plant maintenance turnarounds, the new bolting procedure was used in several areas. New torque methods and tools were used on heat exchangers and reactors in the methanation area. Travelers for critical joints across the plant continue to be developed. This is an ongoing process.

Goal: Evaluate the potential emissions of tanks without emission controls and initiate the process of designing and installing the emission controls if they are needed. Assigned to engineering.

Update: Dakota Gas' Environmental and Process Engineering Departments evaluated each storage tank on the plant site with respect to Environmental Protection Agency (EPA) federal regulations. Six tar oil tanks were identified as potential candidates for emissions controls. One tank already has an environmental control system. Two tanks in the tank farm (FB-6003A/B) require emissions control devices. The environmental regulations regarding three tanks in the boiler house area were unclear, so DGC sought clarification from the EPA. The EPA clarified that those three tanks do not require environmental controls.

Burns and McDonnell was contracted to determine the available control device technology suitable for FB-6003A and FB-6003B. Two options were deemed suitable, and cost estimates were obtained. DGC is currently pursuing a stripping column to remove the light hydrocarbons from the tar oil prior to storage in FB-6003A and FB-6003B. The Environmental Department submitted a compliance plan to the EPA. Engineering continues work on the stripping column as DGC awaits approval from the EPA. An equipment operational date of Oct. 31, 2012 is planned.

Goal: Revisit 2009 goal to improve safety around ponds. Assigned to engineering.

Update: Options for the hazards associated with working around the ponds was discussed at a recent meeting. The tire ladders currently in place proved not to be a solid solution to the problem, so the addition of fences was discussed. Cost estimates for adding fences around ponds AD8111 and AD8116 were obtained last week and are currently being reviewed. A possible addition of a permanent fall protection system that would allow maintenance the ability to freely move inside the fence while being tied off is also being considered. A meeting is scheduled for June 30 to continue the discussion.

Goal: Complete repairs and make upgrades to structural steel and ash water bins in the ash handling area. Assigned to maintenance.

Update: Bids are out for the installation of new structural steel. The steel has been ordered and should be installed yet this year. These projects are just some of the many safety, security and environmental activities underway at the Synfuels Plant this year. These particular plant-wide projects received a relatively high hazard score from employees during annual hazard review meetings held in the fall. The scoring system used in the hazard review process allows Dakota Gas to prioritize projects for problems that otherwise may not be addressed in a timely manner.