Oil flooded screw compressors have characteristics of rotary type compressors and are used widely in industries because of their high efficiencies, small foot print sizes and long maintenance intervals. Oil-flooded screw compressors are capable of achieving high compression ratios with single steps and their applications are spreading as lubrication oil and oil-separation technologies have improved.

Oil Flooded Screw Compressor

One of the applications where oil-flooded screw compressors are advantageously used is fuel gas compression for gas turbines. High discharge pressures are required for fuel gas compressors to improve the power generation efficiencies of gas turbines.

Requirements for sulfur content reduction in automobile gasoline and diesel fuel have increased worldwide for environmental protection, and petroleum companies are required to reduce the sulfur contents in fuels. The main process to reduce sulfur in fuels is the desulfurization process using hydrogen, and a screw compressor is used in the process.

Features

1) High discharge pressure: up to maximum 100barG,

2) High suction pressure: can handle suction pressures up to 100barG, which may be reached during pressure variations, and can be used for the recycle compressors of desulfurization with low differential pressures.

3) Low energy consumption

4) Small foot print size: The high reliability of the screw compressor does not require any spare machine, enabling the reduction of its installation space area compared to other types (reciprocating-type and centrifugal-type) for a given wind volume capacity.

Applications: Fuel gas compression for gas turbines; Compression of various gases used in petroleum refining and petroleum chemistry; and Oil & Gas service.

Contributed by Teri Elliott, Vice President Business Development

Electricity constitutes on average 82% of compressed air system operatings costs over a 10 year period.

Many people are surprised to discover that operating costs throughout the life of compressed air equipment greatly exceeds the initial purchase price. In most cases, the annual energy cost alone will exceed the purchase price in the first year of operation. Locating and repairing leaks, reducing inappropriate uses, adding air receivers, reducing pressures, and recovering heat are all good strategies.

Before you can decide on which strategy is best to improve your system’s energy costs, you must first baseline your system by taking measurements to quantify the efficiency of the compressed air system in its current state. The baseline figures establish your current system’s efficiency, cost, and reliability. These measurements include power, energy, pressure, leak load, flow and temperature.

Improving and maintaining peak compressed air system performance requires addressing individual components, as well as the supply and demand sides of the system. On the supply side, it’s important to calculate costs required to produce the compressed air. An analysis of the system’s demand side is critical as it’s the main overall cost driver in producing compressed air. Consider the following when looking at your system’s demand side.

• Identify the air uses, along with cfm and pressure
• Determine the power before and after making any system changes
• Determine overall leak levels
• Calculate the compressed air cost for a given process or piece of equipment using flow meters
• Operate the system at the lowest possible pressure
• Turn off the air to any idled equipment
• Verify that compressed air is the best alternative for the application
• Monitor pressure drops by installing gauges at various points in the main distribution piping
• Adjust controls after every change to optimize the savings

Baselining your compressed air system is an excellent way to calculate your potential dollar savings and report the facts to management to assist in making better decisions on new equipment selection and the mode of operation of existing equipment.

Contributed by Teri Elliott, Vice President Business Development

An inconsistent supply of dry air will cause production problems such as erratic performance, downtime and maintenance. The presence of water will lead to the formation of rust and scale in the air piping system and the solid contamination will foul equipment.

Air dryers and inline filtration products will not perform if they become overloaded with liquid contamination and water can back up into the compressor.

The volume of condensation in a system will vary with changes in weather conditions because the amount of moisture in the air being compressed is determined by the temperature and relative humidity of the inlet air that enters the compressor. A 200 HP compressor operating in a climate of 60 degrees F with 40 percent relative humidity will generate approximately 50 gallons of condensate a day. However, that same compressor operating in a climate of 90 degrees F with 70 percent relative humidity will generate approximately 260 gallons of condensate a day.  

There are several types of drains available to remove the condensation from compressed air systems. A manual drain is a ball or gate valve that is installed at a drain point in the air system. These valves have to be opened manually to dump the condensation.

Float operated drains use a float mechanism in a housing to control the valve that dumps the condensation. The float will rise as condensation accumulates in the housing. At a preset point, the outlet valve will open to automatically drain the condensation.

Timer drains have an electronic timer that activates a valve to dump the condensation. You can adjust the drain cycles by setting the number of cycles per hour and the length of time the valve will stay open during each cycle. The theory is to set the timer for a long enough period to completely drain the condensation without setting it long enough to waste compressed air. The problem is that the amount of condensation will vary according to changes in the temperatures and relative humidity of the ambient environment. This means that the settings will have to be adjusted to compensate for climate and seasonal changes.

Electronic sensor drains are often called “zero air loss” drains, and will have electronic sensors monitoring the level of condensation within the housing. Electronic drains are typically the most expensive. One sensor opens the outlet valve to dump the condensation when the housing registers as being full. Another sensor will close the outlet valve before completely draining the condensate to avoid wasting air.

It’s important to understand and effectively manage the condensation in your air system; otherwise it will affect your equipments’ reliability and durability.

Contributed by Teri Elliott, Vice President Business Development

The emissions reduction push started with the 1990 Clean Air Act when the EPA proposed a tiered emission-reduction plan for nonroad engines of all sizes. In 2003, the definition of nonroad engines was changed to include all diesel powered engines. This tiered reduction plan gradually lowers engine emissions through 2015 when all four tiers will have been phased in (the Final Tier 4 phase begins in 2012.) Effective NOW – any diesel engine manufactured after January 1, 2008 for use in nonroad product to be sold within the U.S. must meet the new standard which is either EPA Tier 3 or EPA Tier 4i.

As diesel engines are a major contributor of particulate matter (PM), the EPA projected by 2010, nonroad diesel engines would emit as much as three-quarters of all PM if significant changes were not implemented. The current emission regulations are expected to reduce PM and oxides of nitrogen (NOx) by one million tons per year by the end of 2010 – the equivalent of taking approximately 35 million passenger cars off the road.

So what does all this mean for portions of the air compressor industry? Word on the street is that the EPA is currently conducting random site visits where nonroad diesel engines are in use. Hefty fines are being issued and in some cases production is shut down where engines are found to be non-compliant. Drillers use cold start compressor packages on their rigs. Some of these packages were designed for use outside the U.S. and many were put into use prior to the emission regulations. These cold start packages likely use engines that are not currently emission compliant in the US. Should a non-compliant engine need to be replaced, be aware that the wait time on replacement engines is becoming a challenge; therefore, you will probably want to check into your options now. Don’t wait until a non-compliant engine is experiencing problems or for an EPA site visit. It will save you a lot of time and money.

Contributed by Teri Elliott, Vice President Business Development

Most industrial facilities are constantly evolving.  As production processes change and new projects are launched; the landscape of many plants and refineries is altered.  Often, this means the addition of air compressors and air treatment equipment.   

When this happens, there is usually only one factor considered: How big does the new compressor need to be?

While this is undoubtedly important, there’s a consideration that is often overlooked: Is the piping large enough to handle the extra airflow?

After years of expansion in a typical industrial or chemical plant, it’s not uncommon to see many compressors feeding air headers that were originally designed for a single compressor.  This causes huge losses of energy through pressure drop.  It also forces the compressors to work harder supplying plant demand that is well within their capacity. 

While it’s possible to push an impressive quantity of compressed air through a seemingly narrow pipe, there are limitations.  Loss of air pressure occurs at every pipe fitting and diameter reduction – and more feet of pipe means more pressure drop. 

Pipe system configuration also plays a key role in air system efficiency – looped systems equalize pressure and reduce compressor workload – while deadheaded systems often have areas of high and low pressure.  Sometimes, the addition of a new compressor can be avoided altogether by simply changing the pipe system. 

With limited capital budgets, plant engineers often have a hard time justifying the purchase of new piping along with new air compressors.  But if upper management knew the inflated costs associated with improper piping, it would be an easy decision.

Contributed by Steve Mahaffey, Houston Account Representative

A compressor’s air end, motor, air/oil after cooler, coupling element and separator reservoir are the five most costly components of a rotary screw air compressor. Fortunately, Quincy provides an unprecedented Royal Blue Warranty at no additionalcharge that allows a ten year coverage on the air end and five years on the motor, air/oil after cooler, coupling element and separator reservoir. To maintain warranty coverage – name brand parts and oil must be used in the compressor, oil sampling must be conducted every 2000 hours, and recommendations based on the results of the oil sample analysis must be followed. 

A Preventative Maintenance Agreement is an extremely worthwhile investment to protect your compressor since regular maintenance and oil sampling in handled for the owner of the compressor.  All too often, required oil sampling is forgotten by the owner and then warranties are denied when components fail. Motors are also evaluated and warranted through the motor manufacturer, but Quincy stands behind these components also.

Quincy Compressor is committed to providing its customers with the most reliable, quality equipment in the industry and has the warranty and factory personnel to back it up. McKenzie Compressed Air Solutions is 100% committed to outstanding customer service and has the best service and maintenance personnel in the industry .

Protect your investment, protect your warranty, and prevent costly down time by adhering to these recommendations.

Contributed by Mark Clapp, McKenzie Compressed Air Solutions, Field Service Manager

Compressed air leaks- every system has them, but management may not realize the true cost of not repairing leaks. Considering the high cost of compressed air, every facility with a compressor air piping system should contemplate implementing a continuous leak identification and control program.

So how necessary or economically rewarding is a leak identification and control program?

Compressed air systems are usually the single largest user of energy in plants and other facilities, and air leaks can be the single largest user of compressed air. Plants without an air leak management program lose from 30%-50% of their compressed air to leaks. An air system with 300 HP of compressed air in use has approximately 100 HP in potential leaks. At a cost of $ .05 cents per KW, these seemingly innocent air leaks are costing companies over $35,000.00 per year in wasted energy.

A 1/4” leak will pass 104 CFM @ 100 PSI, which at $100.00 per CFM costs $ 10,000.00 per year in energy.

Energy Cost Formula: Input HP x .746 x Hrs x Electrical Rate / motor efficiency

Contributed by Billy Cooper, McKenzie Branch Manager, Schertz, TX

When you buy reciprocating compressors, it is important for the compressor to be sized correctly to your air system. If the compressor is not sized properly and the compressor is not allowed to run long enough to actually heat up, the crankcase can retain moisture as a vapor. This moisture can make its way into the oil and eventually separate; or it can cause rust to develop quickly in the crankcase and lower cylinders. If the compressor is not maintained correctly by changing the oil more frequently, premature failure can occur. Failure can also occur when units are intermittently run for varying time intervals; i.e. 6 hours on Monday and then not again till the following Monday. If the compressor is started intermittenly just to maintain tank pressure, and only runs a short period of time, moisture can be retained. Quincy recommends changing the oil every 500 hours or 3 months unless environmental conditions require you to change the oil more frequently. Quincy also recommends inspecting the oil for contamination and change it when necessary. If these precautions are followed, you will get many years of quality operation from your new compressor.

Contributed by Mark Clapp, Field Service Manager

Many compressed air users utilize filters to trap dirt and moisture, and nearly EVERY compressed air user has an air storage tank.  Both of these items are great for trapping and removing liquid water from the air stream – preventing rust and corrosion in pneumatic tools and process equipment. 

Usually, collected water at the bottom of a tank or filter is released by an automatic drain valve.  These handy devices open on a timer or float mechanism and spout pressurized water from the bottom of the reservoir.   The bad news is most drain valves are equipped with a very small orifice for draining collected condensate – it’s usually only 1/4-inch.  This means that even a small piece of dirt or pipe scale can clog the orifice and prevent the drain from functioning properly.  

For this reason, it’s important to check your filter and tank drains periodically to ensure they’re up to snuff.  Even if your compressor service provider checks them during regular maintenance, make a point to check them between visits for proper operation.  Most electronic drains feature a test button, and almost all drains can be rebuilt fairly cheaply if their seals or diaphragms have been damaged by pipe scale. 

Catching a clogged drain can prevent huge hassles by keeping slugs of liquid water from entering your plant’s air header.  If you need advice on how to check your various plants’ drains, feel free to call McKenzie Compressed Air Solutions anytime at 713-946-1413.

Contributed by Steve Mahaffey, Mckenzie Compressed Air Solutions, Houston