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Chemical Engineering
Chemical Engineering is the branch of engineering that deals with the technology of large-scale chemical production and the manufacture of products through chemical processes. Today, the field of chemical engineering is a diverse one, covering areas from biotechnology and nanotechnology to mineral processing.
1,464 Questions
What is plastic buckets made from?
Many buckets are made out of high-density polyethylene. HDPE is a durable, non-reactive thermoplastic that resists have an effect on and inhospitable climates all through transit or storage. In the blow molding process, uncooked HDPE resin, which in the establishing of the molding technique is referred to as stock, is loaded into a hopper.
What is difference between block flow diagram and process flow diagram?
BFDs provide a complete overview of the whole process in block diagram form. They summarise the major unit operation between process block units. PFDs characterize all the process flows to and from all the equipment required to perform the process within the boundaries set by the BFD
What is stroke length of a pump?
The stroke length of a pump is the distance it travels up before it travels down. The distance traveling up takes in air or water depending on the type of pump. The down pressure expels the air or water.
In a packed or tray column where you have vapor flowing up and liquid flowing down, there is an upper limit to how fast the liquid can drain downwards. The point at which liquid cannot flow down as fast as it is coming into the column is the "flooding point". The actual flooding point is partly dependent on how fast the liquid can flow down with no vapor flowing upwards and the rate at which vapor is trying to flow upwards. Cross sections of the column occupied by vapor are not available for liquid flow - effectively reducing the cross-section for downward flow of the liquid. You also get entrainment of liquid in the upward flowing vapor and drag on the liquid as it fights the direction of the vapor flow - the vapor wants to go up while the liquid wants to go down. This additional drag also slows down the flow of liquid trying to drain downward in the column. There is an analogous condition for two-phase liquid/liquid extraction columns.
What is the difference between clarifier and classifier?
Clarifier removes solids from Liquid and Clarifier removes solids from Gas
Why there are boiling range not boiling point?
I am not sure but may be it is because none of the substances have a fixed boiling point. The substance starts changing its state from liquid to gas before the mentioned boiling point .
For example Boiling point of H2O is 100.but it change it changes its state before it.Therefore there are boiling range not boiling point.
What is a petrochemical engineer?
A Petroleum Engineer is basically someone with a chemical engineering degree who works in refineries.
What countries does Canada export copper to?
for 2013, it was China,
for 2012, it was China,
for 2011, it was Finland,
& for 2010, it was China.
Why is heat trasnfer coefficient of saturated steam is higher than superheated steam?
when steam is at its saturation point for a given pressure, any heat removed will cause liquid water to form. So when saturated steam is used to heat something else, the heated object/substance receives the condensation heat of the steam. The latent heat of condensation/evaporation is 970 But/lb @ 0 psig. On the other, superheated steam only gives up about 10 BTU/lb if it is cooled 20 degrees F. That means that much more steam would be used to transfer the equivalent amount of heat. The liquid water interface also improves the heat transfer.
An Alloy is two metals mixed together.
it is the combination of one or more elements, usually metals. the mixture of elements in an alloy gives it new properties that are different from the properties of the individual element. it often eliminates disadvantages of the pure metal .
How much do mechanical engineers get paid yearly?
How much does anyone get paid? It varies a great deal depending on experience and the nature of the industry. Also, you need to look at the average hours worked per week and the nature of the job
In the U.K newly graduated Engineers can expect on average a starting salary of £18,000.
According to the web page below, Mechanical Engineer at an average of £35,623/annum is the 52nd best paid profession in the UK. (Taken from a survey of over 300 jobs)
http://www.thisismoney.co.uk/news/article.html?in_article_id=411942&in_page_id=2
Advantages of the Miller cycle engine?
The Miller Cycle engine has a very flat torque curve, with maximum torque achieved at 3500 rpm, as compared to Otto Cycle (standard 4-stroke) engines which generally require 4500 rpm or higher.
Due to this lower-end torque ability, the Miller Cycle engine is capable of moving much heavier loads at a much lower fuel economy.
What are the two main causes of corrosion in rig?
A number of commercially available SiC and Si3N4 materials were exposed to 1000°C for 40 h in a high-velocity, pressurized burner rig as a simulation of an aircraft turbine environment. Na impurities (2 ppm) added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si3N4, and formation of substantial Na2O. x(SiO2) corrosion product. Room-temperature strength of the materials decreased as a result of the formation of corrosion pits in SiC and grain-boundary dissolution and pitting in Si3N4.
How do you convert volume to mass?
you need to know the density (mass per volume) of the stuff to be converted,
then it's density divided by mass.
Cycle of concentration in cooling tower?
Cooling Tower Cycles of Concentration As pure water is evaporated, minerals are left behind in the recirculating water. As evaporation continues, the water becomes more concentrated than the original make up water. This eventually can lead to saturated conditions. The term cycles of concentration compares the level of solids of the recirculating cooling tower to the level of solids of the original raw make up water. If the circulating water has four times the solids concentration than that of the make up water, then the cycles are 4. Bleed off is the process of removing a portion of concentrated recirculating water, which is obviously replaced with fresh make up water. By specifying a certain amount of bleed off we limit the cycles of concentration the system can operate at, thus controlling scale formation. Various treatments will let us operate at various cycles depending on the make up water analysis and heat loading of the tower. Bleed off is critical to a successful treatment program. The preferred method of bleed off control is with the use of automated bleed off control. This includes a contacting head water meter, dual timer, chemical pump and solenoid controlled bleed off line. A) Evaporation Loss: from a cooling tower (E) = .001 (Cr) (DT) where Cr = circulation rate in gallons per minute and D T = temperature differential between hot and cold water in °F. The evaporation rate amounts to 1% of the recirculation rate for every 10°F DT. B) Windage Loss: This is a relatively small amount of entrained water lost as fine droplets in the air discharge from a tower. Unlike evaporation which does not contain dissolved impurities windage carries these impurities with it and reduces dissolved solids in the circulating water. Typical values are 0.1% to 0.3% of the circulating rate for mechanical draft towers. C) Bleed off: In the evaporation process the non volatile impurities in the make up water are concentrated. To prevent excessive concentration some of the circulating water must be removed from the system. This is commonly referred to as bleed off or blowdown. The amount of bleed off can be determined from the following equations: % B (bleed off) + % (windage) = % E (evaporation loss) / ( cycles -1) D) Cycles: The previous equation added a new turn to the mix . CYCLES!!!!!!!! This is one of the most difficult terms to understand. I will now attempt to define cycles of concentration. The NACE defines it as: A measure of the degree to which dissolved solids are being concentrated in the circulating water. It is in effect the inverse of blowdown. As pure water is evaporated all of the solids are left behind so they concentrate in the cooling tower water. If we start out with fresh water the tower has one cycle of concentration. When all the fresh water is evaporated ( solids are still in the tower) the tower then refills itself with more fresh water and we have twice the solids in the tower. We now have two cycles of concentration. This process will proceed and scale will form at a certain point. We use bleed off to prevent the tower from reaching the point of scale formation. In an actual tower, this is an ongoing process with continuous addition of make up water and continuous bleed off. The allowable cycles of concentration will be determined by the laboratory. They are based on water analysis, heat transfer rate of the equipment, and feed equipment present. We normally use chloride to determine the number of cycles a tower is operating at. The following equation can be used for this calculation: Chlorides in tower water / Chlorides in make up water = Cycles of concentration For example, a tower operating at a 450 gallons per minute recirculating rate (Cr) , 5 cycles of concentration, 10° DT, and 0.1% windage loss: %B + .1% = 1% / (5-1) which is %B = .25% - .1% therefore %B = .15% of the circulating rate. %B = 0.15% ( 450 gallons/minute) which is 0.675 gallons of bleed off /minute. Total make up water requirements for the system are: Bleed off 0.675 gallons per minute
Evaporation 1% (450 gallons/minute) = 4.5 gallons/minute Windage 0.1% (450 gallons/minute) =.45 gallons/minute Total make up water = 5.625 gallons/minute Total make up water per hour is = 60 minutes/hr. ( 5.625 gallons per minute) = 337.5 gallons per hour. As you can see the higher the cycles the less make up water and blowdown are required. This is true to a certain point where additional cycles do not decrease the amount of make up water and blowdown as drastically. The following graph illustrates the point. As you can see at about 4.5 cycles the curve starts leveling off which indicates higher cycles will not effect the quantity of make up water drastically.
How will you get registration for pwd pune?
Pls go on pwd site gt into Pune PWD building address,personally meet
How can one control the process factors in order to get less maintenance?
make the proper lubrication schedule of all rotating equipment and availability's of all spare parts at proper time.
What is the best liquid trimethylindium source for mocvd since solution-TMI is really a suspension?
DIPMeIn or Di-isopropylmethylindium, a novel and safer liquid alternative to solid trimethyl indium, developed to gain the advantage of high throughput deposition of Indium phosphide (InP) based semiconductors and Copper-Indium-Gallium-Selenide (CIGS) based Solar Cells. (from Definitions database, http://www.definition-of.com/DIPMeIn)
