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Chemical Process Technology

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Chemical & Process Technology

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Wednesday, December 30, 2009

Aspen product including HYSYS and FLARENET used to have English interface. Nevertheless, engineer and operators from certain countries are normally not used to English language and this lead to many error in understanding and operation of Aspen products. Typical countries are China, Japan, Korean, Brazil, Latin American countries, etc.

Aspen aware of this issue and has taken a big step in making their product interface using 9 different languages. There are
  • Chinese
  • French
  • German
  • Italian
  • Japanese
  • Korean
  • Portuguese
  • Russian
  • Spanish
You may download these language packs for the localized products from the AspenTech Support Center.

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posted by Webworm, 10:25 AM | link | 0 Comments |

Sunday, December 27, 2009


Year 2010 is around the corner and it signify that time to renew your registration of Professional Engineer for year 2010.

For those who registered as PE in BEM, you shall submit the following documents (minimum) for the renewal :
  • Filled form "H"
  • Check/bank draft / postal order / money order payable to "Lembaga Jurutera Malaysia" OR pay online via
    • Maybank : www.maybank2u.com.my 
    • CIMB : www.cimbclicks.com.my 
    • RHB : www.rhbbank.com.my
  • Summary of Continuous Professional Development (CPD) 2009 (minimum 50 average hours per year)
  • Photo (for those have not submitted to BEM)
One shall remember, the last date of registration is 31st Jan 2010 and the payment is RM200 (below 60) and RM100 (above 60). Renewal after 31st Jan 2010 will be penalized with additional payment (RM500).

You may pay in other currency following number stated in circular...
  • USD 67
  • AUD 81
  • GBP 45
  • CAD 79
  • EUR 50
  • SGD 101

Details may refer to this circular...

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posted by Webworm, 12:36 PM | link | 0 Comments |
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This post is in response to some readers request for calculation of Wetted Surface Area For VERTICAL Cylindrical vessel with Elliptical Head.

Earlier post "Calculate Wetted Surface Area For Horizontal Vessel With Elliptical Head" has presented an accurate equation may be used to calculate wetted surface area for Horizontal Cylindrical Vessel with Elliptical Head. Simplified equations also presented in "Calculate Wetted Surface Area For Horizontal Vessel With Elliptical Head (Simplified)"
to calculate the wetted surface area.

This principle in deriving Wetted Surface Area For VERTICAL Cylindrical vessel with Elliptical Head was based on the accurate equations as presented in "Calculate Wetted Surface Area For Horizontal Vessel With Elliptical Head". Two main principles used were :
  • horizontal vessel liquid height (H) reached maximum level (d) where H = d
  • horizontal vessel tan-tan length (L) equal to the vessel vessel liquid height ( l) where L = l
Wetted Surface Area (Cylindrical section)
Wetted Surface Area for Cylindrical section can be calculated with following equation :

Wetted Surface Area (Elliptical head)
Wetted Surface Area for Elliptical head (one head) can be calculated with following equation :

d = Vessel inside diameter (m)
l = Liquid height from bottom tangent line (m)

An ellipsoidal heads VERTICAL vessel with internal diameter (d) of 1m and liquid level height from bottom tangent line is 2m. Determine wetted surface area. 
d = 1m
l = 2m
Awet,Cyl = PI x d x l = PI x 1 x 2 = 6.28 m2
Awet,Head = 1.084 x d^2 = 1.084 x 1^2 = 1.084 m2
Total wetted surface area, Awet,total = Awet,Cyl + Awet,Head = 7.37 m2

Ref : "Accurate Wetted Areas for Partially Filled Vessels", by Richard C. Doane, "Chemical Engineering", December 2007

*If you have any useful program and would like to share within our community, please send to me.

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posted by Webworm, 8:39 AM | link | 0 Comments |

Friday, December 25, 2009

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Natural gas is known as one of the world’s cleanest fossil fuel and it burns to form Carbon Dioxide (CO2) and Water (H2O) without  or with minimal smoke subject to composition. Increased world crude demand and price has slowly pushing energy consumers shift from conventional crude based fuel i.e. gasoline, kerosene, etc to natural gas based fuel i.e. liquefied natural gas (LNG), liquefied petroleum gas (LPG), Gas-to-liquid (GTL), etc.

Natural gas conventionally is distributed in gas network. Distribution by gas network will only feasible and cost effective in limited distance i.e. 3000-3500 km. Natural gas may be compressed and stored in very high pressure storage tank. However, high capital cost in high pressure storage tank and high safety risk has driven users look for better transportation and storage option. Liquefying natural gas is one of the option can be most feasible and cost effective. Natural gas in the form of LNG,cooled to minus 160-163 degree Celcius at atmospheric pressure, approximate 600 times smaller than its gaseous state, make it so cost effective in storage and long distance transportation.

In recent net search, there are number of LNG related video clips available in educating, promoting and awareness creation about LNG.

Researchers at Idaho National Laboratory have developed a small-scale Liquid Natural Gas systems to expand the use of clean fuel at an affordable cost.

Pulse of the Port details a proposal for a Liquified Natural Gas Plant at the Port of Long Beach.

One of the largest gas field in the world is located in the sea between Qatar and Iran. Qatar is expanding its fleet of ships to deliver liquified natural gas (LNG) to world market.

BP LNG Tangguh

Terminal operated by Terminale LNG Adriatico Srl, a company owned by Qatar Terminal Limited (45%), ExxonMobil Italiana Gas (45%) and Edison (10%), will be the first offshore facility in the world for unloading, storing and regasifying natural gas. This facility will thus play a key role in increasing Italys energy security and will make the Italian natural gas market more competitive.

The world's largest oil and gas project Sakhalin-2 has begun to produce LNG for the world market. Russia's first LNG cargo will be delivered to Japan.

Second LNG tanker for the Sakhalin-2 field

The following video clips were presented earlier in "LNG and Supply Chain".

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posted by Webworm, 8:04 AM | link | 0 Comments |

Monday, December 21, 2009

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In process plant, there will be scenario for two and/or more pressure reduction devices (PRD) downstream piping discharge to a common header. Typical example is blowdown / restriction orifice to flare header. During plant wide total plant blowdown, all blowdown valves may be opened simultaneously or opened in group. Different PRD will results different level of PWL.When two Sound power sources are combined, it is understood that the total combined Sound Power Level will increase due to two energy stream are combined. However these energy streams are transmitted in wave form, the resultant Sound Power level will not be added arithmetically i.e. 1+1=2. In earlier post "Calculate Combined Sound Power Level (PWL) Using Graphical Method", an graphical method using PWL adder is presented.

The total combined Sound Power Level is equal to "PWL adder" (which estimated base on PWL difference between both stream and from several experience equations ) plus maximum PWL out of both streams.

Combined PWL = Maximum PWL + PWL Adder

Analytical Method
This post will present another analytical method to calculate combined PWL for multiple streams (PWL1, PWL2...)

Total combined Sound Power Level

PWLC = 10 Log10 [+ 10^(PWL1 / 10) + 10^(PWL2 / 10)+...]

Two Pressure control valves with PWL of 160 dB and 166 dB discharging to a flare header. Calculate combined PWL.

Graphical method
Assumed PWL attenuation due to piping is ignored.
PWL,diff = 166 - 160 = 6 dB

PWL adder = 10 ^ (0.4771 - 0.0795 x 6) = 1 dB (refer earlier post).

Combined PWL = Maximum PWL + PWL Adder
Combined PWL = 166 + 1 = 167 dB.

Analytical method

From above analytical equation, 
Combined PWL = 10 Log10 [10^(166/10)+10^(160/10)]
Combined PWL = 167 dB

Obviously analytical method is simpler and faster.

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posted by Webworm, 2:24 PM | link | 0 Comments |

Sunday, December 20, 2009

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Pressure safety valve (PSV) or pressure relief valve (PRV) is commonly used to protect a pressure containment part i.e. vessel, column, etc from overpressure. It is one of the code approved type of overpressure protection devices. This type of device is reclosing type where the mechanism of devices is designed such that it will stop relief when the pressure is reduced to it reseat pressure. Besides PSV, rupture disc (RD) and rupture pin are also code approved type of overpressure devices. This type of device is non-reclosing type where it will continue to relief until all inventory is completely evacuated from the system or with operator intervention.

Earlier post "Visualise Pressure Safety Valve (PSV) Assemblies & Operation" presented some features about the PSV type and also a video clip for typical construction and operation of a conventional PSV. This post will present PSV valve disc movement and flow distribution inside a PSV.

PSV valve disc movement and flow distribution inside a PSV is simulated using CFD modeller, CFX 11.0 . Following video clip shows how a spring loaded pressure relief valve works under over-pressure condition.

You may notice that high mass flux is on the disc facing PSV outlet nozzle.

Following is another video clip shows oscillating movement of PSV disc during relieving condition.

Above oscillating movement generate a oscillating forward flow which is believe one of the cause for valve chattering. Read more about PSV chattering in "PSV Chaterring is Destructive...The ways to Prevent...".

Thanks to Songxguan

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posted by Webworm, 7:12 AM | link | 2 Comments |
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FREE Chemical Engineering Digital Issue for Dec 2009 already released !

Chemical Engineering Magazine as just released Dec 2009 issue. If you are the subscriber of Chemical Engineering, you should have received similar notification.

Interesting articles for this month :

40th Kirkpatrick Award Announced
Seven companies are honored with the announcement of this year's Kirkpatrick Award winners. This biennial prize, bestowed since the 1930s, recognizes the most noteworthy chemical engineering technology commercialized anywhere in the world during 2007 and 2008

Screeners Target Efficiency
Screening system manufacturers look to squeeze more out of their equipment

Building A Better Dryer
Although they are notorious energy hogs, drying systems can be made more efficient

FAYF Control Valves
This one-page guide outlines how installed gain graphs are prepared and used

Maximizing Heat-Transfer Fluid Longevity
Proper selection, monitoring and maintenance can protect fluids from damage due to thermal degradation, oxidation and contamination

Smooth Your Retrieval of Plant-Design Data
Even after construction and startup, plant design data are needed for operations, maintenance and revamps. But working with a plethora of formats and platforms introduces its own set of challenges

Millichannel Reactors — A Practical Middle Ground for Production
Reactors with millimeterscale dimensions provide mixing, heat transfer and other advantages over devices with larger dimensions, while boasting increased robustness compared to mcrodevices. Here are tips to consider for using them

If you are subscriber, you may access previous digital releases. Learn more in "How to Access Previous Chemical Engineering Digital Issue".

If you yet to be subscriber of Chemical Engineering, requested your FREE subscription via this link (click HERE). Prior to fill-up the form, read "Tips on Succession in FREE Subscription".

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posted by Webworm, 3:04 AM | link | 0 Comments |

Saturday, December 5, 2009

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A primary factor in achieving highly reliable, effective sealing performance is to create the best fluid environment around the seal. Selection of the right piping plan and associated fluid control equipment requires a knowledge and understanding of the seal design and arrangement, fluids in which they operate, and of the rotating equipment. Providing clean, cool face lubrication, effective heat removal, personnel and environmental safety, leakage management and controlling system costs are among the specific factors that must be considered. API has established standardized piping plans for seals that provide industry guidelines for various seal arrangements, fluids and control equipment. API 682/ISO 21049 standards have default (required) connections and connection symbols for seal chamber and gland plate connections based upon the seal configuration. It is recommended that the latest edition of these standards be reviewed for up-to-date requirements, when these standards are mandated for a piece of rotating equipment.

JohnCrane, one of the most reliable manufacturer for piping plan for seal has presented a simple booklet for piping seal plan. The intent of this booklet is to illustrate the common connections that are utilized for the various piping plans, regardless of the equipment type, and therefore use generic names for connections. The end user and/or equipment manufacturer may have specific requirements that dictate what connections are to be supplied and how they are to be labeled. In the piping plans illustrated, the “Flush” connection noted for the inboard seal of a dual seal may originate from a number of suitable sources. For example, the “Flush” for piping plans 11/75 or 32/75 may be the product (Plan 11) or an external source (Plan 32).

This piping seal plan booklet illustrate and describe piping seal plan features as an aid to help you determine what support system requirements will maximize the performance reliability of your fluid handling rotating equipment application.

Source : JohnCrane


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posted by Webworm, 7:34 PM | link | 0 Comments |

Wednesday, December 2, 2009

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Rules of thumbs said that every 50D pipe length results approximately 3 dB Sound Power Level (PWL) attenuation where D is in meter (m). This is presented in "Measures & Technique In Eliminating / Minimizing PWL". This post will base on this simple rule-of-thumbs to generate a simple equation for Sound Power Level attenuation due to pipe length.

For every pipe length of 50D, the PWL loss will be 3 dB,

PWL loss per meter of pipe length = 3 / 50D = 0.06/D

Sound Power Level attenuation for any pipe length of L,

PWLLoss,L = 0.06 L/D

PWLLoss,L = PWL loss per meter pipe length (dB/m)
L = Pipe length (m)
D = Pipe internal diameter (m)

Following is typical graph for Unit PWL versus pipe ID.

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posted by Webworm, 5:48 AM | link | 0 Comments |