How Does the Purity and Quality of Gas Affect Costs?
Nitrogen and oxygen are essential supplies in many industries, including food & packaging, lighting, fabrication, oil & gas, electronics, welding, and pharmaceutical. Annual gas production in the UK now exceeds 4 million tons. Unfortunately, purchased supplies are delivered in pressurised bottles to a higher purity specification than is often necessary. Confusion abounds regarding purity, quality, and related cost implications. Over-specified nitrogen gas, delivered by truck, is costlier than using nitrogen gas produced to the exact specification required.
The purpose of this article is to consider economical gas procurement options and discuss the differences between gas purity and quality.
Understanding Gas Purity and Quality
The purity of nitrogen gas refers to its concentrated form. High purity levels, moving up on a spectrum from 90% to 99.999%, create various related implications.
Nitrogen supplies are typically a blend of nitrogen and oxygen. For example, a mixture of approximately 95% nitrogen and 5% oxygen is not uncommon. Having a nitrogen purity higher than necessary is wasteful in industrial or commercial settings.
Gas quality and gas purity get conflated, however, they are quite different. The quality of nitrogen gas refers to how few contaminants are present within the supply. These contaminants may include elements such as metal particulates, moisture, and oil.
Lower-quality supplies do cause long-term issues with expensive industrial equipment that relies on high-quality gas sources. This results in higher rates of equipment breakdown or complete failure, along with less efficient operations during production runs.
The Cost Implications of Gas Purity
Producing nitrogen gas at a higher purity level is not simply a matter of adjusting production parameters. The separation process during production coupled with more extensive purification procedures increases the production cost for highly specified nitrogen.
Extra compressed air is required to produce a more substantial amount of gas. In addition, a larger compressed air generator is required to keep pace and deliver the higher compression levels needed. Operating large generators at a higher compression level increases the energy required. At a time when energy costs continue to rise, reducing electrical consumption is top of mind.
We frequently see applications where ultra-high purity is unnecessarily used. Many only need high purity instead. This is wasteful and costlier in equipment, electricity, and delivered gas supplies. Considerable cost savings can be made by adjusting purity levels to only what is required, and no more.
Purchased Gas vs On-Site Generation
Purchasing gas can be challenging for businesses that rely heavily on it. Most gas suppliers require long-term contracts to plan their production. This commits your business to supply agreements that may not always be in your favour. Being contractually obligated does not shield your business from price volatility. Instead, changes in the price of raw materials and production costs are often passed on to the end customer. Also, road delays, planned roadworks, and the rising cost of diesel fuel have a knock-on effect on the transportation of gas supplies to business premises. Carbon emissions are unavoidable with regular gas deliveries too.
In contrast, on-site gas generation sidesteps many such obstacles and ongoing concerns. Whilst upfront air compressor costs can be considerable, ongoing cost savings can be offset with gas production versus supplied gas. Your business can produce sufficient nitrogen or compressed air to match requirements with no need for extra space to store excess canisters on-site. Furthermore, adjusting production to provide the correct gas purification level substantially reduces production costs. So much so, that the switch to on-site production usually pays for itself within a handful of years.
In an uncertain economic and supply environment, increasing control over vital gas supplies is a net positive even without the expected cost savings.
Factors Influencing the Cost of On-Site Gas Generation
Air compressors come in different sizes and capabilities to support compressed air and nitrogen generation. The smallest cost a few thousand pounds, while larger ones are considerably more expensive. Variable speed drive compressors from Atlas Copco are energy efficient compared with other options, however, it all depends on what your business needs are. At Control Gear, we offer a consultation to develop a complete framework based on your unique requirements. This is necessary because installing the wrong high-pressure system will only harm your operational capabilities and bottom line.
When the system is insufficient for your needs, it must run flat out to produce the quality and purity concentration needed. This is unsustainable. Alternatively, a larger integrated air system requires a substantial capital cost and more time to pay for itself. Having a properly sized compressed air system is critical as around 80% of the total cost is spent during its operational life.
Delivered gas is commonly over-specified versus actual requirements. Operational and maintenance costs are considerably reduced when not requiring ultra-high nitrogen purity levels. The quality of produced gas is unaffected.
Selecting the Right Purity Level for Your Needs
It is important to review the purity level requirements for any industrial equipment used, whether it be welding equipment or compressed air required for beer production, as the purity level can vary widely. For example, beer production manufacturing may require a purity of 99.5% or the quality of the final product is affected. However, natural gas line purging requires at least 95% and possibly higher. Laser cutting equipment needs at least a 97% purity, but some equipment demands a higher specification.
By re-examining all current equipment (and planned equipment purchases in the future), it is possible to determine the maximum purity required. Also, smaller gas production runs using different purity settings create the possibility for individualised gas supplies for certain equipment. Substantial long-term cost savings are achievable through greater efficiency using generation systems.
It is important to ensure that gas used on sensitive applications is not heavily contaminated as this can produce inferior results. Do not, therefore, ignore gas quality factors as this can negatively impact the business.
Conclusion
Gas supply contracts are restrictive and far costlier than on-site gas production using modern air compressor technologies. Lower purity levels directly lead to substantial cost savings when producing gas at your premises. While some applications require ultra-high purity, most do not. Often, this allows for the repayment of the capital investment and operating costs for an on-site system within 24–36 months.
Reducing the carbon footprint by eliminating gas deliveries is better for the environment. Energy requirements during production are reduced when gas purity levels are set lower to match operational equipment needs. This further reduces demand on the power grid.
Looking for the most cost-effective solution is worthwhile for medium to heavy gas users. Optimising your gas supply strategy often pays for itself in just a few years.
Contact us to consult with one of our experts at Control Gear. We can create a detailed framework based on your exact requirements.