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PT. Woolu Sarana Tehnik

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Demikian info yang saya dapat dari PT. Woolu Sarana Tehnik



IGCC: Integrated Gasification Combine Cycle Technology

Panel on “Clean Coal Technologies” in ODTU Alumni in Ankara

Dear Energy Professional, Dear Colleagues,

We had a meeting on Saturday afternoon 23rd February 2008 at the main conference room of “Chamber of Engineers” head office in Ankara Thessalonica Street. The meeting was held with participation of leading senior/ retired members of local energy business, former General Managers, former operation managers, senior researchers of various public enterprises, as well as senior local energy experts.

Flow Diagram IGCC

Flow Diagram IGCC

The subject was “Clean Coal Technologies” which is actually the code name for Integrated Gasification Combined Cycle technology. IGCC is a new technology to answer global warming.

This new technology produces synthetic gas from coal. Synthetic gas has almost one fourth of the heating value of average natural gas.

IGCC technology is first innovated by Germans during WW2 to produce gas and/or liquid fuel for the fighting war vehicles in an environment with no petroleum resources, and further developed in South Africa during world embargo against their apartheid practices in their domestic politics.

Since the equivalent cost per barrel is/was around 50 US Dollars for the synthetic fuel, it was not feasible in the past to apply “clean coal technologies” since it had no chance of competition against low petroleum prices then. However the time has changed and petroleum now costs more than 100 US Dollars per barrel, therefore IGCC technology is now an attractive fuel option.

Our guest speaker, Dr Iskender Gokalp is a Turkish national scientist, Directeur in ICARE, Institut de Combustion, Aérothermique, Réactivité et Environnement, UPR3021 du Centre National de Recherche Technologique, “Propulsion du Futur” in 1c, Av. de la Recherche Scientifique, 45071 Orléans cedex 2, France, http://www.cnrs-orleans.fr/icare/

He comes to Turkey, to his homeland, one week for each month to pursue and execute a project to grand PhD scholarships to young Turkish engineers/ scientists in France on coal utilization, combustion technologies, supported by Turkish Coal Board and European Union under current FB7 program.

He created many scientific publications, and also had great influence in international scientific circles. He recommends us to carry out more research on “Clean Coal Technologies” on local Turkish Lignite specifically on low heating value coal mines, to justify its application and competitiveness.

He advises that local lignite coal could be the best option for application of integrated gasification. Your humble writer sincerely feels that Dr.Iskender GOKALP has all reason to advise on application of “Clean Coal Technologies” in local lignite reserves.

It is also our sincere feeling that clean-coal technology is a must. Energy tops the agenda of all local winter meetings. Next-generation coal is going to need to continue to be part of our energy future for our country. It is abundant, it is locally available, in the sense that we control the supply.

Next-generation coal typically refers to capturing and somehow sequestering or storing the carbon that coal produces. It also envisions reducing or eliminating emissions as coal is burned. It is possible to continue relying on the fossil fuel while minimizing its impact on the environment.

We cannot ignore coal, we should find better ways to utilize local lignite coal. That is important because electricity demand will ever increase in the future.

We all know that Coal has a CO2 problem, Wind has a reliability problem, Solar has a price problem, Nuclear power plants have price, radiation and unsafe disposal problem, so all of those technologies have opportunities and they all have problems.

What we can say about coal, is that we have it locally. We have it in a greater supply.

Synthetic gas production could be a bid expensive but the rest of the system is well-known combined cycle power plant.

Prevailing overall market price is around 1200- 1500 US dollars per KW installed capacity for 600-1000 MWe power plant test sizes. By localizing the technology, we can substantially reduce that first installations cost.

On the other hand local low LHV lignite has current fuel cost less than 2 (two) US Dollars per million BTU gross, whereas imported coal cost is 6- 8 US Dollars gross, Natural gas cost is around 8-10 US Dollar, and imported LNG price in spot market is around 17-18 USD per million BTU.

Senior experts have an ideefixe for application of IGCC on high heating value bituminous coal or steam coal. On the other hand, Dr Gokalp says that IGCC has potential application on low heating value lignite. It is for sure that we do not know if IGCC is perfect match for our lignite. All we have to do is to allocate more funds for more research on local lignite.

We shall have a panel on “Clean Coal Technologies” in ODTU Alumni Association Visnelik premises in Ankara on 10th March 2008 Monday at 1900 hours.

Dr Iskender Gokalp will be one of four distinguished panelists. The other panelists are Prof Dr Bekir Zuhtu UYSAL, Director of Clean Energy Institute of Gazi University, Dr Selahaddin ANAÇ GM of Turkish Coal Board, and Mr. Orhan Baybars ME’79, former site construction manager of Afsin Elbistan-B thermal power plant.

Panel will be conducted in Turkish, and it is open for all interested parties. Entrance is free-of-charge. We have free coffee/ tea services. Please do participate if you would be in Ankara on that day. Your comments are always welcome.

Haluk Direskeneli
ODTU ME’1973 – Ankara MMO 6606

Sample calculations of Boiler Pumps and ID / FD Fans

Sample sizing calculations for BFW pumps and Fans for a typical Coal fired Boiler generating steam of 50,000 Kg/hr at 67 kg/cm2 and 485 degC. (110,000 lb/hr at 950 PSI & 905 F). Feed Water inlet at 105 C and Exhaust gas temp at 150 C.
Let us first calculate heat load and fuel consumption of the above boiler.

coal boiler

coal boiler

Pressure and temp at 1. Superheater Outlet : 67 Kg/cm2 & 485 C
2. Steam Drum : 73 Kg/cm2 & Saturated
3. Economizer inlet : Water inlet at 105 C

From Steam tables,
Enthalpy of Superheated steam , Hsh = 809 Kcal/ kg = 1456 BTU/lb
Enthalpy of Drum water , Hdwat = 305 Kcal/kg = 549 BTU/lb
Enthalpy of inlet water , Hwat = 105 Kcal/kg = 189 BTU/lb

Assume 3% Blowdown from Boiler.

Total Heat Load of the Boiler = Total heat absorbed by water to convert to steam + heat absorbed to get superheated + Blow down losses
= 50000(809-305) + 50000 x 1.03 x (305-105)
= 35.5e06 Kcal/hr = 140.87e06 BTU/hr

Fuel consumption = Heat Load/ (HHV x Efficiency)
= 35.5e06/ (7278 x 0.8649)
= 5639 Kg/hr = 12428 Lb/hr of coal

From previous article on Combustion and efficiency,
Wet gases = 14.05 and Air = 13.12 kg / kg of coal

Therefore, Exhaust gases produced = Fuel consumption x UnitWetGas
= 5639 x 14.05
= 79,228 Kg/hr of wet gases
Combustion Air required = 5639 x 13.12
= 73,984 Kg/hr of combustion air

Feed Water required = 50,000 x 1.03 : 3% Blowdown
= 51,00 Kg/hr

Sizing Calculations :
a) Boiler feed Water Pumps :

Two pumps of 100 % capacity are required one for working and one for standby.

Each pump discharge capacity minimum= 51500 Kg/hr
= 51500/950 : 950 kg/m3 water density
= 53.8 m3/hr
Margin on discharge capacity : 15- 25 %.
Take 20% margin in this case.

So discharge capacity of each pump : 53.8 x 1.2
= 64.6 m3/hr =say 65 m3/hr

If Recirculation valves are not provided, you need to add min recirculation flow to the above figure, which may be about 6-10 m3/hr depending up on pump type and make.

Pump head required = Drum Pressure + Drum elevation + Piping Losses + Control Valve Loss + Other valve losses

= 75 Kg/cm2 + 2.0 + 2.0 +5.0 +2.0
= 86 Kg/cm2
= 86 x 10/0.95 mts of water head at 105C
= 905 mts of WC

Provide up to 5% margin on head. So final Pump head is 905 x 1.05 = 950 m of WC
So BFW pumps (2 nos) rating is 65 m3/hr at 950 m of WC with feed water at 105 C.

b) Sizing calculations of FD Fan :
Forced Draft Fan is required to pump in primary combustion Air into the Boiler furnace. Air from FD fan passes through Air Heater before entering furnace through Grate. Secondary Air Fan (SA fan) supplies secondary combustion air in to the furnace. Usually primary air is 70 -80 % of the total air and balance is supplied as secondary air through SA fan. Secondary air is supplied at a higher pressure to help fuel spreading on the grate called as pneumatic spreading.

Total combustion Air, Kg/hr = 73,984
= 73994/(1.17 x 3600) m3/s :Air density-1.17kg/m3
= 17.56 m3/s

Primary Air , 70% of total , m3/s = 0.7 x 17.56
= 12.3 m3/s

Take 20% margin on discharge capacity. So FD Fan flow is 1.2 x 12.3 = 14.76 m3/s

Head required = Draft loss across Air Heater + Grate + Ducting & others
= 75 mmWC + 75 + 50 mm : Approximate
= 200 mm WC (approximate)
Take 15-20 % margin on head. So FD fan head should be about 230 mm of WC.

Therefore, FD fan rating is 15 m3/s of air at 230 mm WC static head.

Power requirements of FD Fan :
Let us assume Fan efficiency as 75% and Motor Efficiency as 90%.
Power required for FD Fan, BHP = Flow x Head / ( Efficiency x 75.8 )
= 15 x 230 / ( 0.75 x 75.8 )
= 60.7 HP

Motor HP required = 60.7 / 0.9 = 68 HP
Annual cost of operation assuming 7 cents per KWH and 7200 hrs of operation per annum. 0.74 is factor for converting HP to KW. Pl note that unit Electricity charges vary widely across different countries.

= 68 x 0.74 x 0.07 x 7200
= $ 25, 362 /-

c) Sizing calculations of SA Fan :
Secondary Air Fan (SA fan) supplies secondary combustion air in to the furnace.
Secondary Air , 30% of total , m3/s = 0.3 x 17.56
= 5.27 m3/s

Take 20% margin on discharge capacity. So SA Fan flow is 1.2 x 5.27 = 6.3 m3/s
SA fan static head is about 630 mm WC.
Therefore, SA fan rating is 6.3 m3/s of air at 650 mm WC static head.

Power requirements of SA Fan :
Let us assume Fan efficiency as 70% and Motor Efficiency as 90%.
Power required for FD Fan, BHP = Flow x Head / ( Efficiency x 75.8 )
= 6.3 x 650 / ( 0.7 x 75.8 )
= 77.1 HP

Motor HP required = 77.1 / 0.9 = 86 HP
Annual cost of operation assuming 7 cents per KWH and 7200 hrs of operation per annum. 0.74 is factor for converting HP to KW. Pl note that unit Electricity charges vary widely across different countries.

= 86 x 0.74 x 0.07 x 7200
= $ 32,075 /-

d) Sizing calculations of ID Fan :
Induced draft fan or ID Fan is required to evacuate the exhaust gases from Boiler to atmosphere through Duct collectors and chimney. Usually ID should take care of draft loss across the Boiler from furnace to Air heater and then draft loss across Duct Collectors like ESP, Wet Scrubber or mechanical type Cyclone dust collectors .etc.
Total wet gases, Kg/hr = 79,228

Gas Density = 1.3265 Kg/Nm3
Therefore, gas flow in Nm3/hr = 79,228 / 1.3265
= 59227 Nm3/hr
= 16.6 Nm3/s

Gas flow at 150C in m3/s = 16.6 x (273+150)/273 = 25.7
ID Fan capacity taking 20% margin on flow = 25.7 x 1.2
= 30 m3/s

ID Fan static Head = Draft Loss in (Boiler + Duct + Dust collector)
= 150 + 50 + 50 mm WC : Approximate
= 250 mmWC

Taking 20% margin on head, ID Fan head = 250 * 1.2 = 300 mm WC

Power requirements of ID Fan :
Let us assume Fan efficiency as 75% and Motor Efficiency as 90%.
Power required for ID Fan, BHP = Flow x Head / ( Efficiency x 75.8 )
= 30 x 300 / ( 0.75 x 75.8 )
= 158 HP

Motor HP required = 158 / 0.9 = 175 HP
Annual cost of operation assuming 7 cents per KWH and 7200 hrs of operation per annum. 0.74 is factor for converting HP to KW. Pl note that unit Electricity charges vary widely across different countries.
= 175 x 0.74 x 0.07 x 7200 = $ 65,268 /-

Power Plant Adds Fly Ash Process

Dominion Energy has just completed a $46-million Carbon Burn Out (CBO) Fly Ash facility at its Brayton Point power plant in Somerset, Mass.

Now in full production, the new CBO system produces a consistent, low-carbon Class F fly ash suitable for use as a substitute for Portland cement in producing
concrete and in other construction applications. Fly ash, used on roads and interstate highways for some 50 years, is a byproduct of the combustion of pulverized coal. More than 68 million tons were produced in 2001 by coal-fired electric and steam generating plants.
Dominion’s Brayton Point is one of those producers. According to Michael Kaczmarek, ash marketing representative for Dominion, the 1,600-megawatt plant is the largest coal- and oil-powered generating station in New England, with 1,160 of the megawatts coming from the combustion of coal.

Kaczmarek said that Brayton Point burns about 3 million tons of coal per year in its coal-fired boilers, adding that all of the coal is delivered by ship.

“The power plant burns 10,000 tons of coal per day when all coal-fired boilers are online. If trucks hauled Brayton Point’s coal it would take 333 18-wheel dump trucks per day to keep it going or a truck every 4-1/2 minutes,” he said.

Coal is pulverized into a powder as fine as talcum powder. It is then pneumatically blown into the boilers where it combusts as well as natural gas. Boiler tubes extract heat from the boilers, cooling flue gasses and causing molten mineral to harden and form ash. The mineral portion of the coal, which does not burn, as well as 8-percent to 12-percent of residual unburned carbon remains. Coarse ash particles — the bottom ash or slag — fall to the bottom of the combustion chamber, while the lighter fine ash particles — the fly ash — remain suspended in the flue gas. Brayton Point produces approximately 250,000 tons of coal ash per year.

Coal fly ash can be used a substitute for Portland cement in making concrete ready mix, but only if the carbon levels are 2-1/2 percent or less, Kaczmarek pointed out.

To produce fly ash of this quality, Dominion invested in the construction of its new CBO facility.

Capable of processing more than 300,000 tons of ash per year, the CBO facility employs the patented technology of Progress Materials Inc. Fly ash, containing residual carbon from the power plant, is fed into a fluidized bed combustor, where it is initially heated by a natural gas startup burner. Once the ash reaches a temperature of approximately 800 degrees Fahrenheit, the carbon within the ash auto-ignites. At that point, the burner is turned off, and the combustion process becomes self-sufficient with the carbon in the ash feed alone. After at least 45 minutes in the CBO unit, the processed ash is removed having the carbon reduced to specification.

Dominion built a 40,000-ton storage dome together with a truck load-out system. The ash storage silo is one of the largest in the United States, and the largest in New England. It stores winter CBO ash production for use in the summer construction season.

The load-out facility has a 200-ton load-out silo with two-truck load-out bays, each with its own truck scale. Automatic equipment transfers fly ash from the 40,000-ton storage dome into the truck load-out silo keeping it full for truck loading.

The load-out facility has the ability to be self-loading or loaded by an attendant. In the self-loading mode the driver pulls his truck into the enclosed truck bay, exits the truck and climbs a safety platform to the top of his pneumatic tanker where he lowers the dustless loading chute into his hatch, and then exits the truck bay. He enters the control room and swipes an electronic ID card that identifies him to the ash marketers’ dispatch system.

This dispatch system processes the information required to load his truck and prints a bill of lading. When all the information is exchanged the driver pushes the load button and the system loads 85 percent of the load into the truck in a fast fill mode, pauses for two minutes to let the ash settle, then loads the last 15 percent in a slow fill mode to the weight sent by the dispatch system.

Fly ash has many applications in highway and other construction, and its use has been promoted since the early 1970s by the Federal Highway Administration. The Environmental Protection Agency has also been supporting the use of the material because of its environmental benefits, since its use increases the life of concrete roads and structures by improving concrete durability. When fly ash is utilized to replace or displace manufactured cement, it results in a net reduction in energy use and greenhouse gas and other adverse emissions. In addition, using fly ash lowers the amount of coal combustion products that otherwise would be disposed in landfills.

Among its many applications, fly ash is used in concrete admixtures to enhance concrete performance, combined with lime and aggregate to produce stabilized road base course, mixed with water and Portland cement to produce flowable fill, and as a borrow material to construct fills and embankments.

Other fly ash uses include adding the material to hot mix asphalt to increase the stiffness of pavements, and to water and other materials as a grout to fill voids under concrete pavements without raising slabs.

Brayton Point’s fly ash is being marketed by Headwater Resources, a subsidiary of Headwaters Incorporated, a nationwide company that supplies materials from coal combustion products. Stephen Berlo of Scituate, Mass., is the company’s New England representative.

Dominion Energy, owner of Brayton Point, is one of the nation’s largest producers of energy, with assets including over 28,000 megawatts of power generation, 6,000 miles of electric transmission, about 6.3 trillion cubic feet equivalent of proved natural gas reserves, 7,800 miles of natural gas pipeline, and about 950 billion cubic feet of storage capacity.

# By Paul Fournier

Injector / Ejector pada STG

Injector pada sebuah steam turbine generator bisa di rupakan seperti sebuah pompa yang menggunakan ‘ venturi effect ‘ dari sebuah ‘ converging – diverging nozzle ‘ dengan tujuan meng-convert energi tekanan (pressure energy) dari sebuah ‘fluida yang bergerak’ menjadi sebuah energi percepatan (velocity energy) yang pada akhirnya akan menciptakan suatu area yang bertekanan rendah yang mampu menarik fluida pengisi untuk di mampatkan kembali kemudian di rubah lagi dari energi percepatan menjadi energi tekanan.
Fluida yang bergerak tersebut bisa sebuah uap air, cairan atau gas. Sedangkan zat yang masuk ke dalam nozzle penghisapan bisa sebuah gas, sebuah fluida, bubur/slurry atau debu gas (dast-laden gas stream).
Diagram damping melukiskan sebuah in/ejector yang sudah cukup modern. Ini menggambarkan sebuah ‘motive fluid nozzle & converging-diverging outlet nozzle’. Air, udara, uap air atau bentuk fluida lainya pada tekanan yang tinggi akan menimbulkan sebuah gaya gerak (motive force) pada inlet.Efek Venturi, bagian dari prinsip bernoulli tersebut teraplikasikan pada teknologi in/ejector ini. Fluida yang bertekanan tinggi dirubah menjadi energi percepatan (high velocity jet) pada leher converging-diverging nozzle yang mana hal ini akan menyebabkan terjadinya area bertekanan rendah pada daerah tersebut. Area bertekanan rendah tersebut kemudian menghisap fluida pada suction ke converging-diverging nozzle sehingga bercampur dengan motive fluid.

Kesimpulannya adalah, energi tekanan yang ada pada inlet motive fluid dirubah menjadi energi kinektik dalam bentuk percepatan pada leher converging-diverging nozzle, kemudian ter-expand di dalam divergent diffuser, energi kinetik ini di rubah kembali menjadi energi tekanan pada diffuser outlet (seperti aturan pada prinsip bernoulli).

Sebagai rancangan parameter, maka formula berikut sangat penting :

  • The compression ratio of the injector, P2 / P1, is defined as ratio of the injectors’s outlet pressure P2 to the inlet pressure of the suction fluid P1.
  • The entrainment ratio of the injector, Ws / Wv, is defined as the amount of motive fluid Ws (in kg/hr) required to entrain and compress a given amount Wv (in kg/hr) of suction fluid.
  • The compression ratio and the entrainment ratio are key parameters in designing an injector or ejector.