Case Study: Methanol Metering Pump System

A methanol metering system with ten pumps fed by three tanks with eight discharge points starts out as a neat set of simple lines on a process diagram. Designing and making the system a reality however, requires careful coordination of the needs of operators, maintenance personnel, the installing contractor, and specifying engineers. From assuring equipment access to maintenance to navigating supply chains and assuring quick, safe installation, Geiger’s team uses creativity and careful planning to produce factory assembled and tested equipment that wouldn’t be possible to build in the field.

Design Requirements For A Methanol Metering System

When the Piscataway water treatment plant was adding supplemental carbon feed for enhanced nutrient removal, they needed a complex pump station. The methanol metering system was designed to be fed by three tanks with through-the-wall connections and had eight separate discharge points, and needed to accommodate multiple possible carbon sources with a wide range of viscosities. Half of the pumps were intended to discharge to four of the connections, while the other half would discharge to the remaining four. However, any of the pumps could be fed by any of the three tanks.

The equipment was to be installed in a Class 1, Division 1, explosion-proof environment and the customer desired pumps that were easily maintainable and could be quickly rebuilt; reliability was a priority. For these reasons, the piping, accessories, and structural supports were all built out of stainless steel. Pulsafeeder Eclipse pumps were chosen because they offer very repeatable metering, a compact size, and are easily rebuilt in a few minutes from parts kits using just a wrench.

In addition to the plants requirements, Geiger recommended our own design parameters based on experience with similar equipment. These included dividing the pumps into back to back pairs of pumps to allow easier handling and installation and orienting the pumps with aisles between them for easy access to every pump, valve, and gauge,

These requirements resulted in a complex piping system that would have made on-site fabrication virtually impossible within the limited space. Therefore, the methanol metering pump system design needed to be transportable. The engineer’s original single line diagram showed the critical equipment pieces but lacked the arrangement due to their significant complexity. Thus, a design process was necessary to determine the optimal arrangement.

As shown in the accompanying image, the original diagram depicted the 10 pumps arranged in two rows with some piping between them. However, if this arrangement were translated into a physical design literally as shown, it would not allow for maintenance or easy access to the equipment. 

original methanol metering system design
The Original Diagram

Methanol Metering Pump Selection and System Design

Next, we had to conceive a layout that would provide access to the pumps and accommodate the interconnecting pipes and accessories required for a fully functional system. Our solution was to arrange the 10 pumps in pairs, projecting off the wall and arranged back-to-back with aisles between them for access. This arrangement allowed for easy breakdown into transportable and manageable units, with the added benefit of fitting through the existing building doors. To facilitate maintenance, we utilized the wall space to provide common manifolds that could be used to valve into any of the pumps, allowing flexibility to feed from any of the tanks. Additionally, we utilized space along the common wall for manifolds and crossover valves to supply the various discharge points. The resulting design can be seen in the plan view image below.

Geiger's redesigned methanol metering pump system
Geiger’s Plan

The design was completed in SolidWorks to provide a fully detailed, three dimensional model of the equipment. The design was analyzed to assure accessibility of every piece of equipment, valve handle turns, and visibility of gauges. Every pump was given sufficient clearance for maintenance, and pump and motor assemblies could be removed without disassembling the manifolds. We included drain ports and flush ports that were easily located to facilitate equipment flushing and decontamination before completing maintenance, including the Pulsafeeder Eclipse pumps’ rapid rebuild. The entire system was designed with ease of operation and access in mind.

Lastly, we aimed to expedite the on-site installation process by fabricating  and testing the entire set of 5 duplex pump skids as a complete unit. This allowed us to test the assembly at the factory, identifying and addressing any functional or mechanical issues before it arrived on-site. This process helped ensure there were no issues during installation and was a critical step in providing factory-assembled equipment.

final methanol metering pump system
Final System Assembled for Factory Testing

Key Takeaway

This project emphasizes the need to spend just has much time on a system’s design and layout as on pump selection. Armed with only a basic, single line drawing, it would have been virtually impossible to fabricate this equipment in the field. Instead, thanks to Geiger’s careful design process, the equipment arrived on site as assembled units that were identical to the approved design. Installation was fast, and final testing could be completed in just a few days with Geiger’s support, rather than many long weeks.

Our extensive experience with system design has taught us that it is essential to consider the needs of the operator, to maintain and use equipment with a minimum of hassle. Additionally, we consider the needs of the installer, ensuring that the equipment fits through doors, can be safely transported, and can be easily and quickly assembled in the field. We also take into account the needs of the equipment itself, ensuring proper relief valve placement, ease of priming, and adequate straight runs for the flow meter. All these considerations and more are carefully evaluated during our mechanical design process to ensure the entire process from design to installation runs smoothly.  

Geiger provides custom engineered and fully integrated skid systems for a wide variety of applications. We design, engineer, and fabricate industrial quality solutions including pumps, valves, piping, controls, instrumentation and accessories to meet your every application need. To learn more about Geiger’s capabilities, contact our team.