Dateline: April 3, 2007

News
Technically Speaking

North America

Acquisition
Airgas has acquired the U.S. packaged gas business of Linde for $310 million.  The acquisition includes branches, warehouses, packaged gas fill plants and other operations part of distributing packaged industrial and specialty gases and related equipment.  With 130 locations in 18 states with more than 1,400 employees, the business generated $346 million in revenues and $36 million in EBITDA in 2006.  Approximately 50% of the revenues were from gas sales and cylinder rent, with the remainder from sales of welding equipment and supplies.  Airgas plans to sell 17 of the acquired packaged gas facilities to National Welders Supply Company at the close of the acquisition.

World

New European headquarters
Songwon Industrial Co., a South Korean specialty chemical producer, has opened a European headquarter for its affiliate Songwon International in Frauenfeld, Switzerland.   Songwon is aiming to become a strategic partner to customers by positioning itself to supply across the broad range of their polymer stabilizer requirements.

Product development center
BASF is building a product development center in Malaysia to service its Asia-Pacific engineering plastics customers.  The center will be built next to BASF’s engineering plastics compounding plant in Pasir Gudang.  The facility will focus on developing innovative products tailored to the market’s requirements.

Biofuels blends boost
Japan’s Agency for Natural Resources and Energy will begin a study next year to determine whether biodiesel blends could exceed current limits.  The proposed $2.28 million investigation would cover fuel mixture properties, stability, emissions and durability.  Biodiesel from fatty acid methyl ester derived from rapeseed, palm oil and soybeans will be tested in addition to vegetable oils and biomass.  The study is aimed at determining if biodiesel blends of more than 5% are viable.

Oil and gas field
The Japan Petroleum Exploration Co. (Japex) and Mitsubishi Corp. will invest $400 million to boost production of the Kangean oil and gas field in East Java now that they own 50% of the block.  The two companies bought the stake for $360 million from PT Energi Mega Persada (EMP), with the holding being split evenly between them.  EMP holds the remaining equity in the block.  Japex and Mitsubishi believe the new investment will boost the block’s production to 60,000 barrels of oil/day within three years from around 10,000 barrels of oil/day currently.       

Technically Speaking

What is the difference between a dessicant dryer and a refrigeration dryer?

"Adsorption dryers are one type within the generic class of 'desiccants'. Adsorption is unique and very effective because it uses the effect of van der Waal forces to capture and retain selective molecules on the surface of an adsorbent (usually activated carbon, silica gel, activated Alumina, and Molecular Sieves). When the retained molecules (sorbate) are water, the operation is one of drying the parent fluid. This adsorption unit operation can be done in the liquid or gaseous phase. Drying is usually done on gaseous phase. It is very important to note the difference between ADsorption and ABsorption. The two are entirely different unit operations and are designed differently.

Refrigeration “dryers” merely cool a compressed, humid gas phase and subsequently separate the liquid condensate from the gas, leaving a water-saturated gas at the operating pressure & temperature of the cooler. On subsequent pressure reduction and gas heat up, the relative saturation is reduced. It is obvious that you cannot obtain an actual, presurized dew point at a temperature lower than approximately 35 °F; otherwise the unit would freeze up with water ice.

Please take careful note of the following: To judge the absolute differences between both unit operations you should measure the amount of minimum water content that each process can accomplish at the same, process pressure. And the absolute measurement should be in PPM (mass) not in dew point or PPM (volume). The reason for this is that if you have a critical service the dried gas is going into, you want a definite mass measurement of the quantity of water you are introducing into the system.

In these regards, the adsorption dryer has all other types of dryers beat – and beaten to a pulp! The refrigeration dryer or deliquescent-type lab dryers (like CaCl₂) can’t come close to the product quality levels that the adsorption dryer can achieve with ease and simplicity: product gas with less than 1.0 PPM (mass).

Adsorption dryers come in two generic types: TSA (Temperature Swing Adsorbers) where heat is used to reactivate the spent bed, and PSA (Pressure Swing Adsorbers) where pressure is use to reactivate the spent bed. PSA has a process fit in some unique applications, but generally cannot be justified where there is no useful application for the reactivation gas stream. TSA is the process of choice if you want good, clean, ultra-dry compressed air for critical services and instruments.

Refrigeration dryers require a much larger pressure drop through their system than do TSA, fixed bed adsorption dryers. This is common knowledge because of the many mechanical constraints imposed on the mechanical type. I design TSA adsorption dryers to operate with 20-25 ft/min of superficial velocity and only have a pressure drop of 0.5 psi (maximum) across the entire unit – something a refrigeration type can’t do."

Art Montemayor via Cheresources.com Forums