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Active Contributor

Join Date: Jun 2008
Location: Malaysia
Posts: 24

Steam consumption for 1MW of electricy

05/21/2010 11:22 AM

Hello friends,I am in the dark since my GM is asking me to calculate how much bio fuel is required to generate 1MW of electricity.FYI,we operate palm waste(empty fruit bunch/fibre/woodchips/palm shell) as fuel for our bio mass boiler to produce steam for extraction condensing steam turbine and also process steam.I need your help to determine the exact or almost accurate amount of fuel to burn.

Thanks

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Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
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#1

Re: Steam consumption for 1MW of electricity

05/21/2010 12:19 PM

2 to 3 thousand tonnes per year.

According to this site:-

http://www.abelard.org/briefings/replacing_fossil_fuels.php

scroll down to the orange section "A big power station" (1000 MW) will use 2,190,000 tonnes of oil (from fossil) per year.

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Join Date: Jun 2008
Location: Malaysia
Posts: 24
#7
In reply to #1

Re: Steam consumption for 1MW of electricity

05/23/2010 11:54 AM

Thank you very much for all the comments.Only God can repay you.Very much hope to hear again next time.Thank you again.

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Guru

Join Date: Jul 2006
Posts: 1001
Good Answers: 84
#2

Re: Steam consumption for 1MW of electricy

05/21/2010 11:30 PM

Rosli,

Two pieces of information you must have before you can give an answer to your GM:

  1. The thermal efficiency of your power plant (the ratio of heat content of the input fuel to the heat content of the output electricity). In conventionally fueled plants with a boiler and a steam-driven turbine and generator, this efficiency is in the range of 30-40%. Hopefully, you can do better than an estimate with this type of range.
  2. The thermal heat content of your bio mass you are using as a fuel source. Unlike coal or fuel oil or natural gas, bio mass will have a significant amount of moisture. As it is heated to the combustion point, this moisture needs to evaporate; thus some heat is lost.

When you know these two numbers, it should be very simple to calculate the amount of fuel needed to generate 1 MW of electricity.

--JMM

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Guru

Join Date: Dec 2006
Location: Hop around Toronto, New York & Karachi
Posts: 1848
Good Answers: 19
#3

Re: Steam consumption for 1MW of electricy

05/22/2010 12:45 AM

1 kW =

1.6 ~ 1.8 kg rice husk

3.75 m3 bio gas

1.7 m3 coal gas

A biomass gasifier can generate enough gas for 5.0MW.

A coal gasifier can generate for 4.6 MW.

(steam turbine can take 3.5 ~ 7.5 kg/kw depending on type,stages,operating pressure and temperature so difficult to inform exact unless you already have a turbine and its data).

detail me your existing generators/power requirements, steam boiler capacity Tph on my email duconems@yahoo.com and I will help give you calculation.

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Guru

Join Date: Nov 2009
Location: Izmir, Turkey
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#5
In reply to #3

Re: Steam consumption for 1MW of electricy

05/22/2010 9:56 AM

The numbers don't make too much sense.

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Guru

Join Date: Dec 2006
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#6
In reply to #5

Re: Steam consumption for 1MW of electricy

05/22/2010 10:33 PM

3.75 m3/hr bio gas = 1 Kw so 1 MW would require 3750 m3/hr of bio gas produced from bio mass. This will have a calorific value of 1259~1500 Kcal/kg.(Note his present natural gas requirement is around 290 ~ 300 m3/MW at 8550 Kcal/kg)

Bio gas is 5.7 times more because of lower calorific value. He needs to modify his existing Gas Generator to accept this gas and though it will operate also but will derate by 35% or he goes for separate biogas/syn gas generators.

He should opt for a biomass gasifier complete with cleaning & electrostatic tar removal system of 4000 m3/hr capacity.

Once you know the kcal/kg calorific value of anything you can calculate any fuel requirement gas/liquid/biomass. I am doing both Coal Gasification/ Biomass Gasification Projects so I gave the figures which are results from my own calculation as well as those picked up after internet research.

Unless he contacts back with his requirement of Steam for Process + Power requirement, details of Plants, fuel data of all types he wants to use etc. i cannot help him further.

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Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1246
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#4

Re: Steam consumption for 1MW of electricy

05/22/2010 9:15 AM

Dear Mr.Rosli,

This is a simple matter or problem.

You pl.furnish the followinf data.

1. What is the Boiler Pressure, Capacity, and Final Steam Temperature. Feed water temperature?

2. What is the condensate Temperature returning from the Process to the Boiler and quantity. ? First of all whetehr the condensate returned from the Process is suitable for use in the Boiler, if so what is the Quantity and Temperature.?

3. What is the Turbine Steam Inlet Conditions, Extraction Quantity and at what Pressure and Temperature, it is extracted.?

4. What is the quantity of Steam is condensed and at what vaccum and what is the quantity of power drawn from the turbine.

5. How much make-up water (treated) is used for Boiler and what temperature.?

6. What is your Boiler Efficiency and What is the Flue Gas Exit Temperature.?

7. What is the Calorific value of the Fuel.? This is required to calculate the quantity of fuel.

STEPS INVOLVED:

1.HEAT RATE/kW.Hr = 860K.Cal/kW.Hr.

2. Steam per kW.Hr = 860/ HEAT DROP/Kg.of Steam in Turbine. Here the heat drop will vary for extraction steam(depends on pressure and temp.) and condensing steam.

DHAYANANADHAN.S,

INDIA

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Active Contributor

Join Date: Jun 2008
Location: Malaysia
Posts: 24
#8
In reply to #4

Re: Steam consumption for 1MW of electricy

05/24/2010 12:49 AM

Particulars might help us.

Bio mass boiler:

Capacity : 66 T/h

Pressure :42.5 barg.

Temperature :Design at 415 deg Celcius(fall depending on fire side condition)

Steam Turbine.

Extraction temperature:about 205 deg Celcius.

Extraction pressure :4.5 barg.

Vacuum:0.10(minus)

Process steam flow:11kg/s to about 15kg/s.

Process steam temperature :above 140 deg Celcius.

Feedwater temperature:about 110 deg Celcius.

CV for fuel: 10178kj/kg(moisture about 40%)

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Guru

Join Date: Dec 2006
Location: Hop around Toronto, New York & Karachi
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#9
In reply to #8

Re: Steam consumption for 1MW of electricy

05/24/2010 1:22 AM

10178 KJ/KG X 0.2388 = 2430.5 Kcal/kg

10,000 kcal heat /2430.5 = 4.1 m3 bio gas

est. 82 m3/T steam on natural gas 8550 kcal/kg

so 82 m3/T steam x 4.1 m3 = 336.2 m3 bio gas /T steam x 66 T = 22189.2 m3 bio gas/66 Tph

A bio mass gasifier = 5000 m3/hr capacity so 22189.2/5000 = 4.4 or 5 sets required with dust cleaning/cooling/tar removal system.

Your moisture content need to be reduced to <10 % with a drier and all loose biomass (saw dust/wood saplings/rice husk etc) to be in briquette form.

There is only one manufactuer in india making this on turnkey basis.

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Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1246
Good Answers: 26
#10
In reply to #8

Re: Steam consumption for 1MW of electricy

05/31/2010 2:16 PM

Dear Rosli,

You have given data as required, i will give full calculations to-morrow.

Please, till then, bear with me,

thanks,

DHAYANANDHAN.S

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Guru

Join Date: Dec 2006
Location: Hop around Toronto, New York & Karachi
Posts: 1848
Good Answers: 19
#11
In reply to #10

Re: Steam consumption for 1MW of electricy

06/04/2010 9:24 AM

waiting......waiting......waiting...

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Guru
Engineering Fields - Mechanical Engineering - New Member

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Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1246
Good Answers: 26
#12
In reply to #11

Re: Steam consumption for 1MW of electricy

06/04/2010 11:59 AM

Dear Mr. Ducon

Extremely sorry for the delay. Now I started working out and I will send the details. Pl.send me your mail Id. to sd610 @rediffmail.com and in addition to posting in this CR4 forum, I will send to your mail Id. also. If need be I will assume certain parameters and work out, and I will indicate the assumptions made.

Delay is siincerely regretted .

Thanks,

dhayanandhan.s

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Guru

Join Date: Dec 2006
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#13
In reply to #12

Re: Steam consumption for 1MW of electricy

06/04/2010 3:12 PM

Dear dayanandhan,

Good day my friend.

Since i am working on alternate syngas from coal & biomass gasification so I'd love to have whatever technical knowledge i can get from you. Please do not take me wrong - it is just my urge/passion to learn.

Best regards,
Duja/ducon e-mail:duconems@yahoo.com

web:duconems.com

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