Friday, March 25, 2016

Circulating Fluidized Bed (CFB) or Pulverized Coal Firing (PCF) Dilemma

for Appropriate Local Boiler Technology

Do we have reliable low calorific value domestic coal firing thermal power plants, proven itself with long term in operation? Yes we have, let's name them
Soma-B # 5-6, Seyitömer # 4, Kangal #3, Afşin-B.

These power plants have proved themselves in operation for last 20-30 years. All these plant are very reliable in domestic low quality coal firing. They solved their problems of low calorific value domestic coal burning. They may have some other shortcomings which should also be solved in time.
They may have difficulty in soot blowing, so you must add up more number of soot blowers.
Their dust filters may not meet emission standards, so you should build bigger dust filters.
If there is no FGD (flue gas desulphurisation), so you must add a new one.
If NOx emissions do not meet required national standards, so you add Low-NOx burners, if still not enough, then you install SCR ( Selective Catalytic Reactor).

Those investors who invested on domestic coal firing thermal power plants, do not disclose the results of their investments so far. There are no success stories, no high efficiency, no high availability information told. Leaked news are not so encouraging. One a big thermal power plant project is completed, the project results are shared by everyone. This is an acceptable public relations activity, an acceptable advertising in the market. We read the reports, academic papers, listen to conference presentations, we congratulate our peers and share their experiences. Over the past 10-years, the new investments are carried out mainly on CFB technology, but there is nothing disclosed in those investments, nothing shared with public.

On the other hand there are lots of presentations, commercial and academic papers, articles, news reports everywhere all available for public access.
There is a deep silence on these on indigenous coal firing power plants mostly with the new CFB technology to burn low calorific value local coal. Until now, nobody explained anything. Billions of US $ were invested for those plants. Hence there is no technical evaluation, no information, nothing. After evaluating this secret situation, my humble comment is as follows,

It is found so clear that our low calorific value local coal with 50-55% moisture (water) is almost impossible to fire without pre-heating, dehumidification, and could not be fired properly without installing dewatering systems. Excessive amounts of supplementary fuel oil firing is necessary to fire the coal if delivered to boiler combustion chamber as-is.

FarEast companies offered their off-the-shelf CFB designs to our local investors, as a panacea, backed by cheap prices and cheap financing by Exim banks funds.
They impressed our local investors with their ultra cheap prices. However their CFB technology does not meet to fire our high moisture low heating value local coal. So in the end, top management decision makers of local investor companies are aware of the current situation that they made the investment decision. Until their time for retirement, they do not make any sound and stay silent.

Your writer believes that the appropriate technology to fire our domestic coal is in Afşin-B plant 4x350MWE, which has "indirect pre-heating pulverized coal firing" coal combustion technology. The original designer German Company went bankruptcy due to various financial reasons at their homeland. Company withdrew from the market, and is not active anymore. But designers, engineers are still working in the commercial environment.

Their subcontractor Turkish companies (let us name them Gama, Tekfen, Tokar) upgraded themselves and became leader engineering companies serving worldwide to build new thermal power plants. Enka, Prokon, Efor companies have similar references.

Our experienced engineering contractor companies can recreate the original proven designs very easily in time if opportunity is placed to the private entrepreneurship. Those companies can also employ the original designers in their local design offices as expatriate consultants if they really need so. So you can ask our engineering companies to quote for 150-350 MWe thermal power plants. I believe that they have such capability to bring together such work in time.

Our local engineering companies have sufficient number of references, ample work experience and competency. So we employ domestic engineering, fabrication, construction, contracting, as well as domestic labour. We all know that there are hundreds thousands of engineers working in international contracting companies. We can bring together the same number of local engineers. Foreign companies employ people like us, there is no difference.

After an overseas construction job is completed, the contractor fulfills the contractual requirements, operate the plant in commissioning, temporary acceptance period, get the completion and receives the final acceptance, then leaves the plant. After that the operator is all alone to run the plant with all problems appearing later in time.

If the contractor is in the home country, then they are responsible to operate the thermal power plant all life long maybe 20-30 years operation. Contractor has to solve every problem, satisfy the client at all times in case problems, accidents, troubles arise. If not, then the client not only stops working with you, but tells all others in the market their displeasure that you can not work any more.

Continuous work with your client keeps you alive, fit, and helps you to improve your design and your technology, makes you competitive in the global market.

Haluk Direskeneli, is a graduate of METU Mechanical Engineering department (1973). He worked in public, private enterprises, USA Turkish JV companies (B&W, CSWI, AEP), in fabrication, basic and detail design, marketing, sales and project management of thermal power plants. He is currently working as freelance consultant/ energy analyst with thermal power plants basic/ detail design software expertise for private engineering companies, investors, universities and research institutions. He is a member of ODTÜ Alumni and Chamber of Turkish Mechanical Engineers Energy Working Group.

Ankara, 18 February 2016
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