8 replies to this topic

[Adriaan]

Electric power is provided by installations that burn fossil fuels (waste incinerators DO provide some power but their contribution is marginal). The efficiency of such installations is entirely too limited, mainly because they have to dump waste energy. In some places the waste heat is partly used to heat houses and such near the powerplant and that raises the efficiency quite a bit (though that isn't much use in a hot summer).

A few years ago I read that the coalfired powerplants in the USA were SO inefficient that a minor upgrade to them would result in such an efficiency improvement that for the same amount of fuel used there would be an extra electric output that would be enough to provide ALL the electricity needed in Japan!

Currently fuel prices are at a level that investments into efficiency improvement are not always economically viable (and I am NOT specifically talking about the USA here, mind you) but in the future I think that improved efficiency - specifically of electricity production - is key.

[Chris Haslego]

The point that you make is a very good one! The use of waste heat from industrial facilities for district heating is popular in many places around the world (Sweden is a good case study on this technology, you can see details here: http://www.energy.ro...er/1991/chp.htm).

According to a 2000 report from the U.S. government, district energy was providing only 5% of the needed heating and cooling loads (entire report is here).

Efficiency in the overall power production industry will probably be given more attention in the near future. At the end of 2001, coal was selling for around $30 / ton. Right now, coal futures are selling for around $50 / ton. If the price of coal holds steady or increases, the payback time on efficiency projects should look very attractive. Right now, most power companies are probably still locked into generous contract prices, however, as they expire, efficiency projects may start popping up all over the industry.

Another variable may be that power companies are weighing efficiency investments in old plants versus simply building new ones based on newer technologies. We'll have to wait and see.

[mxmaciek]

Well, cogeneration is country and even more, site specific.

In some cases, heat production can be more important than power generation, and then this is calculated in design. One example you have below:
Dalkia Poland, municipal cogeneration plants were designed mainly for heat:
eletrical power output: 502,85MW
heat output: 2338,00MW
Reason: this city was the polish capitol of textile industry, and plants were supplying steam to factories.

[taskin]

True
efficiency is key now
First everything is economy
second is ecosystem

ofcource is efficiency is important energy production and using
and waste

now wars finished and we understand we will live together with our waste
so efficiency is key
today engines and turbines old design
wherever develop of them they are inefficient
I invent a new rotary piston
everybody things there is no another turbine
you know daily turbines uses kinetic energy
but pistons uses potencial energy
this rotary piston use both of them

I am not understand why not interesting with it

I know economy is first nobody want togive lisence prize

but this reality
what can I do
is everybody stupid?
I am not understand

[JMW]

One of the reasons for this is the historical focus on building large power generation plants as part of (usually) nationalised power generation industries.
This meant that a population would be served with its power from a relatively few power plants. The electricity would, of course, be widely distributed using the grid but heat energy is far more expensive to distribute other than locally.
With denationalisation and unbundling of power utilities the opportunities for autogeneration open up a better situation.
For example, a Textile factory may require lots of steam and power for operation. By generating their own power they benefit by using the heat energy for steam production and the electricity for the machinery.
Auto-producers can then also sell surplus electricity to the grid and supley heat into district heating schemes.
The efficiency of such operations can be far superior to on site steam generation and drawing electricity from the grid but the best efficiency is obtained when the plant can be scaled to supply surplus electricity to the grid and then have heat energy available for district heating. More usually the steam demand would be self consumed and it is the electricity that is surplus.

[mxmaciek]

JWM, not exactly, let me say...

Closer explanation: factories in old towns are located in the areas, where the erection of new steam generator and turbine is possible only if oyu will fire it with gas. In mentioned my me case - coal is much cheaper, but the transport issue in both directions: fuel and ashes, will make invetment in the middle of the city simply impossible.

Lets consider small HRSG, below 50MWe.
All BOP installations, grid connection (both: DH and electrical), cooling (and included in this: auxiliary, sometimes huge, water supply in situations, where dry colling - another not cheap option - cannot be chosen due to plant footprint limitations), waste treatment, waste water neutralization, wastes disposal, chemicals storage, and the plant itself - will create COST. Additionally, you want to fill the DH grid? OK. Because of the plant required reliability, you have to cover at least 72hrs supply of wter in case of leak. How big leak? for typical plant, it would be (110MWe plant) 500-700 cu.m. And, you'll need raw water storage with the volume of 70-900cu.m to backup your production. How about the backup of the steam generation? Two smaller, or just second full scale backing up unit?

In addition to equipment, each of such plant will need permitting, environmental assessment, grid connection, area preparation and adaptation etc.
How about O&M personnel? Fully automated plant? Really? Have you met the plant, which can operate without supervision, and personnel able to take corrective action in the real time? Would you make your all textile (or other) factory output depending on the non-maintained plant?

And, to be more specific:
What will cost more: chemist for 100MW plant, or 10 chemists, each for 10MW plants?
Of course, the constructed site could be low pressure, operating on the cheapest equipment, with softeners only, almost domestic type unit. But not, if you want to fill the DH grid.

Guess, who is the owner of the DH network, which is not only just a network of pipes and heaters, but (as this is indirect heating), set of the automated heat exchangers, booster pumps, valves etc.? Maintenance of such network is complex, complicated and requires large company support to maintain it.
Because of that, water in DH system is not just: hot water, it is not softened water even, but is demineralised and conditioned with corrosion inhibitor, oxygen scavengers etc.
Well, owner will not permit to input into n DH network anything, what can cause corrosion, scaling etc.
And going back to the beginning: do you think, that textile plant manager will be happy, if he will need to employ an experienced chemists on the 24/7days base?

Altogether, it can be a paradox, but bigger plant in this case would be cheaper.

[JMW]

Well, I'm not exactly talking about what might be but about what is.

I mention textile factory as an example because of a particular example in an old town in Portugal. I suggest paper mills or refineries or petrochemical plants. And I did some work at a major refinery in Southern Siberia which did provide the district heating for the town. Refineries and petrochemicals plants are even better placed because they can often substitute off spec product for fuel (the worst quality fuel oil I encountered on a refinery because of this - high quality on spec fuels are worth more being sold than burned).
These are all operations with high energy demands and high steam and water usage.

But I'm not talking coal, fuel oils and gas are both cheap enough to be cost effective and have the virtues of being relatively easily managed.

At the textile mill the initial power plant was one large diesel engine (MAK 43) running on HFO.

Where it also produces steam, that ups the efficiency significantly. OK, in this example they only needed to satisfy their own steam usage to be cost effective and to sell surplus electricity. Whichever you have a surplus of is what you sell. Before the unbindling they bought their electricity and produced their own steam.
Auto-producing is a very profitable enterprise under the right conditions, and without subsidies.
There are many industries ideally placed such as paper mills, refineries and so on where they have high power and steam demands and auto-generation is a great solution when you can sell surplus electricity to the grid.

Talk to any large engine manufacturer and they'll provide the whole package, the engines, generators, civil engineering, financials, they'll even negotiate the contracts with the national grid i.e. they'll take care of all those things you mention as barriers but which are just stepping stones (opportunities).

It is pretty common now to have engines that are dual fuel capable.

At the textile plant I refer to they subsequently installed some gas turbines as well as the large diesel engines so they could take advantage of gas prices when the price breaks favoured gas firing and the diesels for when the HFO prices are favourable.

You get into your car in the morning, you switch on and drive. If you get a problem, you call the breakdown service.
Power stations using engines are pretty much headed that way.
Large diesels are prime movers in marine propulsion. They have to operate at 80-90% rated max. for extended periods without intervention.
The objectives in the marine industry are "unmanned machinery space" and "computer controlled bridge" because they have minimum crews and minimum skills.
These are the sort of things that make auto-production a relatively straightforward choice. In that are a lot of the textile plants went the same way.

Some vessels operate CODAG propulsion systems (Combined Diesel and Gas turbine) so multiple engine types do not necessarily create a skills and maintenance burden, they just add flexibility.

In pretty well any area of industry the trend appears to be the same - toward demanning and deskilling with far greater reliance on fully automated systems and external service and maintenance support as and when required and don't lets forget about telemetry and CBM.

Visit an operation like this one in a textile mill and you'd be surprised how few operators there are and how few skills are on site and since I was first there they've added more engines and increased their flexibility without adding to the work force that significantly that I was aware of.

What initially surprised me most was the attention a major engine manufacturer would pay, during commissioning such a power plant with major teething problems, to the success of an individual new $4000 instrument. But that interest was exactly because it promised to deliver year on year maintenance and calibration free zero skills operation, better accuracy, faster response times and greater functionality. All the things the original isntrument could not deliver but at pretty much the same price.
Do that with every bit of equipment one piece at a time and you can get pretty close to having no one on site at all.

The path to unmanned machinery space is one of replacing each and every piece of equipment that requires maintenance and operator skills with one that does not.
Of course, what you also do is you add more instruments to monitor stuff and telemetry the data to where you keep your core skills and develop management and diagnostic programs to give you all sorts of diagnostics and you adopt condition based monitoring.

[mxmaciek]

Hi there. It will be interesting to hear how they managed to put high pressure pipeline with proper output rate (let's say, from my case, to ctreate 400t/h or the 60bar steam with 313Celsius) through the city?
And, ok, for single factory - yes. But if you have 30-40 factories in one single city (in fact, some of them, in the middle of it) its both: cheaper and easier to put single of couple larger plants.

Of course, in refinery, petrochemical plant - they will use waste fuel from own resources, but unfortunately, textile factory cannot create enough heat from burning waste cotton, wool, polyamides or whatever they are using.

Diesel engines are perfect to create electricity, but, how you would like to use diesel engine to produce steam or DH water?

About the trends in the industry with deskilling.. hmm.. yes, it was. Fortunately what I'm observing now (not limited to Poland observation) is that some plant managers realised that one day of the steam/power turbine outage, related with forced outage of the factory costs a lot more than whole year salary for the qualified personnel who can prevent it.

And, to compare costs: average, located in EU demineralisation plant, lets say: gravel filters, carbon filters, [microfiltration + RO as option, or] Amberpack WAC/SAC-> DG->WBA/SBA, mixed beds, for flow of 260m3/h will cost approximately 4-5M of EUR (cost is based on the bidding documents from 2006, so can be slightly outdated, sorry about that). But, if oyu want to have it unmanned, fully automated with necessary automatically starting backup, all online analyzers - then you have to increase your cost approximately for 50% more.
To be specific, I'm not taling about the typical for small plants hardness sensor, but e.g. m-Alk analyser, Silica analyser, Sodium analyser (both with accuracy down to +/-2ppb), regenerating chemicals concentration analysers, conductivity (with range from 0-1uS/cm after MB) for chemical measurements only.
Above is (as far as I remember) typical spec of chemical online analysers for one of demin stations at CHP.
$4000 for single instrument? You can ask HACH Ultra, how much they will want for Sodimat 9425, for sodium only, to find average price of EUR 7K.

Of course, if the factory have to satisfy their own needs, it seems to be ok. But, another example, few years ago steam producing plnat owned by a coal mine wanted to: input the steam turbine and sell electricity, and to feed DH system in the adjacent town.
Except the turbine and heat exchanger cost, they have had to replace whole water treatment, and they did it changing from unmanned softeners to fully staffed demineralization plant due to LP/IP turbine and DH water quality requirements. I was not assessing this upgrade, but I think that they made calculations what will be more beneficient for them.

Again, all above will be site-specific, and considering that:
- it will be delivering LP/IP steam to factory;
- it will deilver heat for DH of the city larger than 20 houses ;
- it will deliver electricity to the grid;
- it will have to operate constantly, not with the availability factor of something (in this case: backup lines will be required).

In fact, could you provide example of unmanned plant with output rated at 50MWe or 70MWt? I'll be very interestred to see it.

[raj84]

Heating and cooling a two story home always presents some problems.

It's all going to depend on where your thermostats and your return air grills are located.
Neither of the scenarios you have represented above has a true edge on the other.

Here is the optimum scenario:

-Have separate units to feed the upstairs and the downstairs with their own respective thermostats and return air grills. The supply air ducts AND return air ducts should only go to their respective units
-The placement of the thermostats and return air grills will be the key to maximum efficiency.

____________

wafer edge connector
toys for kids