cooling t-Thermal power plantsower

In thermal power projects the circulating water system is most important. The more efficient the system works will keep the power output of the plant in tact. The purpose of providing Circulating water system is for supplying water to the condenser for condensing the LP turbine exhaust steam and also for secondary cooling of boiler and turbine auxiliaries. The circulating water system is normally of two different types. One of them may be once through type in which the system operates without cooling tower and the other type may be closed cycle recirculation type which uses  cooling tower. when cooling water is available in large quantity such as sea water source of water for cooling systems like circulating water systems in  coastal power stations the once through condenser cooling system is used for direct cooling  When plant water is drawn from fresh water sources such as river, canal, lake, and reservoir Closed cycle condenser cooling system using cooling towers is implemented by  the power plants based on fresh water sources to meet their water.. Sea water based cooling towers are also adopted at coastal sites depending upon techno-economic considerations.  Two types of cooling towers are normally used in the power plant. One is mechanical induced draft type cooling tower and the other one is  natural draft type cooling tower. The selection of the cooling tower depends on capital cost and operating expenses and consideration of site specific issues. In general, mechanical induced draft tower are preferred for power plants .The operating expenses of mechanical induced type cooling towers can be optimised when it is constructed very close to pit heads. Natural draft tower are preferred when the power plants are located at load centres (far off from pit head) as these do not involve any rotating equipment, thus saving on costly power. Air flow rate through Natural draft cooling tower depends on the density difference between ambient air and relatively hot & humid light air inside the tower. For sites with

Considerable duration of high summer ambient temperatures coupled with low

Relative humidity values adequate density difference would not be available for

Proper design and operational performance of Natural draft cooling tower . For such sites, mechanical induced draft type cooling towers should be preferred . In case of once through system, desisting arrangement and travelling water screens of appropriate mesh size are provided at the intake section to prevent debris and biological species in source water from entering to cooling water and plant water systems. In case of sea water based cooling water system, debris filters of appropriate mesh size shall be provided at upstream section of condenser for further removing debris from the cooling water and thus reducing fouling of condenser tubes. In the mechanical induced draft type cooling tower is of single or double inlet,cross flow or counter flow type with the fans located on top of the tower. The

natural draft type cooling tower is of counter flow or cross flow type with draft

for air flow through the packing provided by buoyancy effect of hot and humid

air inside the tower shell as compared to outside ambient air. Splash type or film type. However, due to ambient air having high levels of dust, splash type film is preferred for both types of towers Because of high salt concentration; cooling tower drift and salt contamination in the environment are considerations for cooling towers with sea-water makeup. The drift will contain very high (up to 55,000 ppm) concentration of total dissolved solids, hence a sea water cooling tower should not be located close to sensitive equipment to minimize corrosion effect. To avoid long distance drift of high concentration salt water, it is recommended that the distribution system be designed for low-pressure spray nozzles, which will reduce the quantity of water droplets impinging on the drift eliminators. Drift rate is limited to 0.02 to 0.05 percent of the circulation water flow rate.A typical sea-water cooling tower operates at cycle of concentration ranging from 1.3 to 1.5 and size of cooling tower is 5 to 10 percent larger than a similar capacity fresh-water system. This is because sea water, having high salt concentration, lowers the water’s vapour pressure and reduces the evaporative cooling rate by 5 to 8 percent (depending on salt concentration). Approach temperatures used for design of towers must consider the effect salt water has on tower performance. Distribution piping of PVC performs well in salt water service. The fan blades may be of glass reinforced polyester or epoxy coated aluminum.Gear reducers, bearing housings and fan hubs may be made of cast iron provided they are protected with a heavy coating of epoxy enamel. Mechanical equipment supports and welded steel fan hubs should also be protected with a heavy coating of epoxy enamel. Since stainless steel resists salt water very well in areas which are highly aerated, drive shafts and fasteners in the mechanical equipment should be made with type 316 stainless steel.

Model calculation 3 : Direct Manpower calculation Installation of Heavy Tall towers: I explained in my previous posts the details of direct manpower calculation for vessels of lighter weight. The direct manpower calculation and the effort required for erection of heavy tall towers are not simple like normal heat exchanger or small towers. Either bigger capacity cranes of suitable capacity or availability is normally used in such cases. On occasions considering the weight, non availability of higher capacity cranes, economy an alternate arrangement in place of cranes are used for the erection work is used. . This derrick arrangement is called as Gin Pole arrangement. A gin pole (derived from gin, a three-legged lifting device) is a supported pole which uses a pulley or block and tackle on its upper end to lift loads. The lower end is braced or set in a shallow hole and positioned so the upper end lies above the object to be lifted. The pole (also known as a "mast", "boom", and "spar") is secured with three or more guys. These are manipulated to move the load laterally, with up and down controlled by the pulley or block.

The gin pole is considered a form of derrick, called standing derrick or pole derrick, distinguished from sheers (or "shear legs") by having a single boom rather than a two-legged one.Gin poles are also used to raise loads above structures too tall to reach with a crane, as placing an antenna atop a steeple, and to lift segments of a tower atop one-another during erection. When used to create a segmented tower, the gin pole can be detached, raised, and re-attached to the just completed segment in order to lift the next. The process of "jumping" is repeated until the topmost portion of the tower is completed. .In this model calculation my experience in calculating the direct man power was on the basis of using Gin pole or derrick and direct manpower handling the equipment.. This manpower calculation does not include any manpower for operation and supporting activities of the crane movement

The man-hour calculation of the estimator should include the time to be spent by various technicians/Labourers to complete the activity starting from receiving the materials from stores of the owner, loading, transportation of materials from owners stores to contractors storage yard , unloading and storing at contractors storage at site yard, retransportaion to the point of installation if required , surface preparation of foundations along with time required for fabrication/machining of steel shims to be placed below the equipment installation, man-hours required for installation work for accessories or platforms, man-hours required for testing and commissioning, , Also major important factor which involves lot of man-hours is the scaffolding activity. If the equipment to be installed is at lower level or on ground the Man-hours required for scaffolding will be nil. In case if the installation is at an elevation the man hours required for preparation and installation of the scaffoldings are to be considered The normal activities involved in the installation of the Tall towers after receipt of materials at erection sites are preparation of the foundation and bring down the level of the foundation to receive the equipment on top of it with the space available for placing the equipment on top of the foundation. Normally only maximum of 50mm pacer plates are allowed to be placed between the equipment and foundation so that grouting can be taken can effectively. On preparation of foundation check for the condition of the equipment placed on ground on wooden packers.. Tower Installation Hence details provided by me are bare minimum and guide lines for the estimators in indie. The details provided are based on the productivity of the technicians worked then with me and minor fine tuning as per site data’s of the company .and in consultation with the companies site personals more accurate data’s can be decided by estimators Towers ( considering the erection procedure with Gin Pole Derrick arrangement) Slno Detail Weight of equipment up to 100MT Weight of equipment up to 101-200MT Weight of equipment up to 201-300MT Weight of equipment up to 301-400MT 1 Foundation 80hours 80hours 120hours 120hours 2 Installation 2640hours 2960hours 3360hours 3680hours 3 Total 2720hours 3040hours 3480hours 3800hours The above mentioned man-hours calculation does not include the manpower required for receiving the materials from stores up to erection site, activities related to cleaning of equipments, accessory works related with equipment erection work like platform and ladders erection works for the equipment any major scaffolding works,time required for preparation of testing,commissioning,performance guarantee works . The manpower calculation is on the assumption that the equipment will be installed only on the ground.. Based on the above chart let me calculate the man hours required for a Tall Tower weighing 400 MT and installed at ground floor. As per the chart the time consumed for installation of this equipment is only 3800 Man-hours and time required for other activities can be calculated under respective heads and to be added with the basic man-hours. What should be the cost of this 3800 man-hours. It cannot be purely one category like skilled/highly skilled or semiskilled. It is the combination of the technician group engaged in the installation work. Based on the nature of work the category of people are to be divided. in terms of percentages. In this case the highly skilled labourers may not be required much and unskilled workers also will not be required much. So technicians who have capacity to lift and shift the materials may be required more. If we consider total 100% man-hours equals to 128 Man-hours. Out of which Riggers can be considered as 70%( semi skilled) requirement,15% requirement of skilled and remaining 15% manpower will be unskilled to reach total the 100% Skilled Labours -15%.........!5/100*3800 = 570 Man-hours Semi skilled --70%.......70/100*3800 = 2660 Man-hours Unskilled ...........15%........15/100*3800 = 570 Man-hours Cost of installation of the Tower on basic conditions based on the Man hour rates (Minimum wages) of notification by Delhi state Skilled Labours .........(570/8)* 455 = 32,418.75 Semi skilled --- -(2660/8)*414 = 1,37,655 Unskilled Labours..... .(570/8)*374 = 26647.5 Total cost of Man-hours for Erection of 400 MT Tower on Ground using Gin pole arrangement is Indian rupees at the location near Delhi and at this point of time Hence Rate per MT in that location is Indian Rupees 394.21

Starting of project-introduction

Staring of a project-Introduction”

The process through which the expected final product is achieved successfully in terms of time and finance with the co ordination and effect of group of resources can be called as the implementation of the project. The project can vary from product to product depending on the production of the final product. Whatever the product produced at the end it require a standard procedure which we call as project implementation procedures. To conceive a project the accurate estimation of the finance and resources are most essential. The final user of the product in the project is normally called as the owner of the project. The resources required for completion of the projects are deployed either by one company or group of companies are called as contractors of the project. The co ordination between the owner and the contractors during the implementation of the project including either in supply of technical knowhow required for the project or validating the technology supplied either by the contractors or themselves are called as project consultants. These three parties form important roles in the implementations of the project. To carry out the works of individual parties they sure require some mechanism through which their companies earn money. Hence all the companies make their own estimates in achieving their goals without slipping their responsibilities and make profit for the company. It is quite obvious the success of the project not only depends upon the accurate estimate of the owner but also the correctness of the estimates of their working partners like contractors and consultants.       

Owners Estimate: The cost estimates of owners/project consultants/and contractors varyfrom every ones point of view.. The cost estimate of the owner is of normally on a macro basis. Based on the previous experience of the cost incurred in other projects of the same nature and capacity, is considered as basic element for the cost estimates ,taking in to considerations of the escalation factor as per index , duration when the old project was implemented and the present one. Any project can be compared with the human body. Like we have different parts of the body even project have various elements starting from conception till production of the  end product. From inception the feasibility study whether the project is viable in terms of profit and run on long run. Followed by financial and check up of required inputs followed by rough estimate of the project. Many of the projects stops at this stage due to various reasons like UN availability of required in puts. Further progressing projects continue with project work like process engineering/design and engineering .Supply chain management group forms and construction in continuation with testing and commissioning. Even though there are many activities in a project the construction activity plays an important role since it falls on the tail end of the project .Whichever losses and finance for the company is to be managed by the construction group hence its role in project is most important

Even though many micro activities are involve in completion of a project it is worth it to list here the major activities which forms the prime part of a project. It may be an industrial project or others the following steps need to be full filled
1. Feasibility study

2. General estimation of the project

3. Financial tie ups

4. Development of HR and required team to carry out his project

5. Scheduling of the project

6.Tie up  with process engineering company

7.Tie up with design and detailed engineering company

8.Find out major eligible equipment manufacturers

9 Development of infra structure activities

10 To start on site work

11.Testing and commissioning

These are the major heads of activities required to complete the project in macro level. The details of which i shall explain in some other post While a company decided to go ahead with a product the location of the factory wherein the product is produced plays a very vital role. To start with the place must be easily approachable. Connected with near by cities by road/water or air. The infra structure facilities like electricity to operate the plant at competitive cost /one or few of the raw materials required to produce the end product is available either there itself or in the nearby locality. Ample empty space required for the construction of the factory including the place for future expansion. Availability of local force while construction of the factory and for further maintenance of the factory. Availability of construction hiring equipments in the nearby towns. Even though the above cite facilities are very much necessary  ,leading financial institutions and Banks for transaction on day to day basis throughout the starting and till completion of the project are also most important matter to be considered.

                                           To name a project is common for the procedure to identify the  production end products. But in industry it is differentiated by the name of the end product. For Example   power production industries call this project as Power plant project.  Production of chemicals are called chemical plants.  Manufacture of  petrochemicals are called as petro chemical project.  Like  wise other products like cement ,steel, textile, IT are named with their name as projects.

                                           Thermal power plants are most essential need in growing countries to fulfil their power requirements. Mostly Thermal power plants are constructed where sufficient quantities of coal are available in the place itself or in the nearby vicinity where from it can be easily transported. Depending upon the availability of other commodities and inputs the location of the Thermal power plant is decided. Even though there are other sources of power production Thermal power plants are widely used considering the cost of coal is cheaper. Except for few countries the coal cost is very much comparable with other fuels like Diesel/Naphtha etc. In countries like India wherein petrochemical fuels are of scarcity they wholly depend upon thermal power plants. Otherwise the construction cost and maintenance of Thermal power plants over a period of time works out to be most efficient compared to Diesel and other fuels. Countries like China  had already constructed and operating the power plants more than 1000 MW, countries like India still operate with 650 MW maximum . In recent past few 800 MW Thermal plants are under construction. Owing to the large requirement of power up to 30 million MW in future India has plenty of opportunities or the power companies from India and other countries to involve themselves in the development of India