Manufacturing and Energy

Energy: Why important for Process Engineers

technologist — Sat, 10 May 2008 23:15:42 -0700

Fuel for energy is generated by the nature. For example, C1 (carbon in the form of CO2) is naturally synthesizes (photosynthesis in presence of natural UV radiation) to molecule Cn (like starch, sugar or cellulose), which are used directly /or indirectly as fuel/ or feed stocks for fuel generation. Consumption of available fuels higher than generation is creating not only fuel shortage but also leaving behind bad consequences to the environment due to exhausted excess carbon dioxide.

Being desired transformations can�t be avoided in the process industries, higher energy wastages in them demands higher input energy. How energy is wasted in the process industry? To understand it, consider following cases:

Doing more, thus wasting more
Doing more, but using less
Wasting more, thus doing more

Doing more, thus wasting more
For example, pump filling overhead constant level tank at higher flow rate than required, thus subsequently overflowing excess amount of liquid to ground tank. Being pump is operating at much higher capacity than required, excess energy is wasted.

Doing more, but using less
For example, use of higher capacity conveyor for small amount of material transportation. Underutilization of material conveyor wastes more energy for unit production rate.

Wasting more, thus doing more
For example, high number of pipe fittings used in the pipe routing leads to high fluid energy wastage in terms of frictional pressure drop, thus more work is to be done by the pump.

Right amount of energy for desired transformations is the ultimate aim of energy conservation. Reduction in energy wastage to minimum reduces the energy demands in the process plants. Following steps for energy conservations are discussed here:

Good Housekeeping
Optimization of Plant Operation
Hardware Modification or Replacement
Process Modification

Good Housekeeping
This is foremost simple step, which any process industry can easily adopt. Arresting steam leakages, stopping idle operating pumps or mixing agitators, etc. are the typical examples falls under this category. Being the simple steps, it absolutely doesn�t require any financial investment and can be implemented at any time. It requires only the energy conscious culture in the process industry. This step itself can save ~5% in energy bills of the industry.

Simply organizations need culture where everyone from shop floor to top management feels himself involved in the process.

Optimization of Plant Operation
Excess capacity, provided by the plant designer as safety margin, of the plant hardware provides the scope of using it during actual plant operation. Thus, process plant hardware need to be tuned for energy efficient operation. Liquid transportation with maximum flow capacity of the pump, minimizing reflux ratio for distillation column, etc. are the well known examples for process plant optimization. The optimization exercise require either no or minor financial investment. Though some operational time may be consumed for setting rightful optimum parameters, but often results attained are very positive as far as energy saving is concerned.

Hardware Modification or Replacement
Reduced efficiency of existing hardware e.g. scaled or blocked heat exchanger tubes, entry of innovative energy efficient devices in the market like high efficiency distillation column packing, poor selection of hardware at the time of first purchase e.g. lower pipeline size, etc. demands much higher input energy than actually required for desired transformation. Necessary hardware modification or replacement conserves energy in the process plant. Unlike previous two categories, it requires low to medium level financial investment along with process plant stoppage for changeover of the troubling hardware.

Process Modification
Many times overall or part of the process is modified for the sake of overall energy savings. Process routes as well as transformation steps are altered to minimize input energy supplies. It requires extensive studies at various levels starting from paperwork to laboratory, pilot plant & semi-commercial levels. Usually such process modifications require high investments as well as higher implementation time for gaining energy benefits. But they are essential at a stage when business need improvement due to tough market competition.

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Improve efficiency of power transmission equipment

technologist — Thu, 24 Jan 2008 04:48:40 -0700

Power transmission equipment e.g. gears or couplings are the most neglected areas where nobody (including good energy auditors also) focuses for energy saving opportunities.

However, a certain approach or simple steps can improve their efficiency by at least 2% which may result in total annual cost saving in power bill by more than 6%.

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HVAC - Quick Calculation of refrigeration load for Rooms

technologist — Tue, 25 Dec 2007 01:43:53 -0700

A building or room gains heat from many sources. Inside occupants, computers, copiers, machinery, and lighting all produce heat. Warm air from outside enters through open doors and windows, or as �leakage� though the structure. However the biggest source of heat is solar radiation from the sun, beating down on the roof and walls, and pouring through the windows, heating internal surfaces. The sum of all these heat sources is know as the heat gain (or heat load) of the building, and is expressed either in BTU (British Thermal Units) or kW (Kilowatts). For an air conditioner to cool a room or building its output must be greater than the heat gain. It is important before purchasing an air conditioner that a heat load calculation is performed to ensure it is big enough for the intended application.

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Never Ignore Pump Bypass?

technologist — Fri, 21 Dec 2007 05:08:05 -0700

Many of you, especially who are handling projects engineering, may be surprised when & why should I consider bypass for pumps. What is the utility for considering bypasses? Why not only relief valves are sufficient for safeguard against high pressure in the line? The list may be little longer than my expectation�. Here are few things to remember�.

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Parallel Pumping - Its a team effort

technologist — Sat, 13 Oct 2007 00:15:17 -0700

When multiple pumps operate continuously as part of a parallel pumping system, there can be opportunities for significant energy savings. For example, lead and spare (or lag) pumps are frequently operated together when a single pump could meet process flow rate requirements. This can result from a common misconception�that operating two identical pumps in parallel doubles the flow rate.

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New Hot gas expander from GE

technologist — Fri, 12 Oct 2007 23:36:55 -0700

GE Oil & Gas has received GE ecomagination certification for hot gas expander technology that works with a waste gas recovery system to help refineries significantly reduce their energy costs while also lowering emissions.

The hot gas expander for GE�s Power Recovery Air Train features GE�s latest technology and meets the rigid standards of ecomagination, the GE corporate initiative to address challenges such as the need for cleaner, more efficient sources of energy, reduced emissions and abundant sources of clean water.

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Efficient Roof Design

technologist — Tue, 25 Sep 2007 02:36:25 -0700

From an energy efficiency perspective, roof technology has not progressed substantially in hundreds of years, but that is changing with the use of active thermal mass components, reflective pigments and coatings, subventing, radiant barriers and other novel techniques being tested by a team led by Bill Miller and Jan Kosny of ORNL's Building Envelopes group. Their prototype roof and attic system works by reducing attic temperatures by about 22 degrees Fahrenheit during a typical summer afternoon and decreasing the amount of heat that gets transferred through the attic floor to the living space.

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Frictionless compressors - Are they right for you?

technologist — Wed, 01 Aug 2007 21:00:31 -0700

Are they right for you?

Compressors that run on frictionless bearings are an enticing prospect. Dan Foss Turbocor, Inc. is now marketing a line of compressors that use magnetic bearings to provide essentially frictionless operation. These compressors have been on the market for about three years, and now McQuay International is incorporating the compressors into their new line of frictionless chillers.

Using innovative technology that levitates the compressor shaft in a magnetic field, the compressors operate without metal-to-metal contact, making them more efficient, and eliminating the need for an oil management system. Turbocor has recently received three prestigious awards for this design: the ASHRAE/AHR Expo "Energy Innovation" Award in 2003, the Natural Resources Canada's Energy Efficiency Award in 2003, and the U.S. Environmental Protection Agency�s Climate Protection Award in 2004.

How are they different?Here are some of the features, benefits, and concerns to help you decide whether frictionless compressors (or McQuay�s frictionless chillers) are right for you. Each feature is discussed in more detail below.

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