What are the best U.S. odorization, and odorant injection systems and how to select which technology to use for an application? Here is your selection guide for GPL, Preco, YZ Odorizer, King Tool, and Welker systems.
Odorization System Selection Guide
We usually classify natural gas odorization equipment in two categories, chemical injection, and chemical vaporization. The following guide will assist in selecting the best odorization or odorant injection system for tour application.
To begin, the operator will want to know:
- What type of gas is being odorized and the application (e.g., the transmission line, methane producer, farm tap, and so on)
- Where will the equipment be installed?
- Understand the gas properties (e.g., pressure range, temperature range, flow range)
These three factors, as well as the review of the advantages and disadvantages of the systems to follow, will help determine which equipment best suits your application.
Natural Gas Odorant Injection System
Odorant injection systems odorize natural gas at transmission pipelines, cities, municipalities, many medium-size loads, city gate stations, methane producers, and low-volume applications. The chemical injection pumps are actuated differently depending on the manufacturer, though they could be pneumatically-actuated, solenoid-driven, or electrically-driven to inject a known volume of odorant into the gas. Most, Preco and YZ Systems, utilize the pipeline gas to actuate the system, though one manufacturer offers a sealed ventless design (GPL systems are eco-friendly). By adding small volumes of liquid odorant into flowing gas, the gas becomes odorized. In this style of odorant injection, a computer controller monitors the flow which in turn will vary the injection rate.
Advantages of chemical Injection
- Accurately odorizes gas over wide flow ranges
- Built-in alarms (GPL Odorant Injection has mobile alerts, also)
- Remote control access from computers (GPL permits access from smartphones, also)
- Audit trail to demonstrate proper odorization rate and proof of continuous odorization
- Susceptible to lightning damage and backup power required for outages
- Not usually considered for low volumes as there may be too much time between injection doses (GPL systems) provides uniform odorant injection for low flow (even no-flow))
- More costly than evaporative systems
Three top odorant injection system manufactures in the United States:
- GPL models: GPL 750/10000 – Advance technology, eco-friendly, cost-effective systems
- PRECO Pump Injection – Providing systems for high volume and high pressure since 1969
- YZ Systems – YZ NJEX – YZ is a top selling and most popular odorant injection system
Two common vaporization systems are the wick-type and bypass-type.
Wick Type Odorizer
The wick-style system is one of the oldest type for low volume applications less than 500 SCFH. The wick-style unit is known as the “farm-tap” odorizer and perhaps the only way to odorize a single customer. They are used in camps, trailers, instrumentation leak detection, and domestic farm taps. These small units install on a service line near the gas meter. A wick inserts into the odorant and becomes saturated, while the opposite end extends into the gas stream. The odorant draws up the wick and evaporates into the gas, creating the desired smell.
Advantages of wick type
- Simple to use
- Only suitable for low flow and consistent flow applications
- Gas can become over odorized during the summer while gas flow is low
- Gas can be under odorized in winter when gas flow is high
- No tracking ability and challenging to monitor
- Susceptible to liquid contamination, and contamination will impede odorant vaporization
The bypass unit is for a small or low volume system. In this process, part of the gas stream diverts to a tank containing liquid odorant. Most of these systems include wicks to increase vaporization. The amount of gas diverted depends upon the gas flow. The gas flows through the odorant tank and when exiting it is saturated, and returns to the gas pipeline, odorizing it.
Advantages of Bypass
- Easy to fill, install and replace
- Not accurate during wide gas flow variations
- Inaccurate when odorant is contaminated
- Will stop odorizing in freezing temperatures if the odorant is contaminated with water
- Requires monthly inspection
- Releases odorized gas to the atmosphere with each tank refill
Top chemical vaporization manufacturers in the United States are:
- King Tool – wick type and bypass
- Peerless bypass
A variation of the vaporization system that is worthy of mention is the pulse bypass odorizer.
The pulse bypass is a modified bypass unit that permits tracking the gas flow. Here, the higher pressure gas from a pipeline is used to introduce odorant vapors into a lower pressure distribution line. By diverting non-odorized natural gas through an odorant tank, the gas is saturated, then returns to a downstream distribution pipeline. This style is suitable for lower flow applications and while it is more expensive than the traditional bypass it offers cost incentives over feature-rich chemical injection systems.
Top pulse bypass odorization system manufactures in the United States include:
- Welker Odoreyes
If you have questions about the use of an odorization or natural gas odorant injection system, contact us.