Showing posts with label Gas. Show all posts
Showing posts with label Gas. Show all posts

Sunday, January 3, 2010

The Benefits of Renewable Energy Solutions

Some people may not want to admit it, but the world is slowly moving towards an energy crisis. Non-renewable resources such as fossil fuels are much closer than people think to becoming extinct. We have always known that the everyday energy we use is not unlimited, yet it is constantly being taken for granted. Oil, gas, power, even water has limited availability. Yet, we have not taken nearly enough precautions to deal with a very real threat of an energy crisis. When I say ‘we’, I am not referring to the governments of the world, but to all of us, the common people. We are the ones who can make a difference.

To neutralize this crisis, it is important that we learn to reduce our dependency on energy sources that are non-renewable and start focusing on energy solutions that can provide us with a continuous source of energy that will not exhaust any resources. There are 3 main sources of energy which fall into this category: hydro energy, wind energy, and solar energy.

First, let's look at hydro energy.

Hydroelectricity is the most widely used form of renewable energy in the world. It is typically generated on a large scale by way of hydroelectric dams. Although it is indeed a renewable source of energy, hydro energy comes with some drawbacks. Hydroelectric projects have been known to have negative effects on surrounding aquatic ecosystems. One example, is there are studies that have shown that dams along the Atlantic and Pacific coasts of North America have reduced salmon populations due to their preventing access to spawning grounds upstream. A major disadvantage to hydroelectricity although rare, is the risk of dam failure. In Southern China, the Banquio Dam failure resulted in the deaths 171,000 people and left millions homeless. Although it is an effective source of renewable energy, it is not as environmentally friendly as the other 2 main sources of renewable energy, wind and solar power.

Let's look at wind energy.

Windmills have been around for thousands of years. They are older than electricity itself. In pre-industrialization times, they were used to propel sailboats and ships, they were used to pump water, and they were used as a means of natural ventilation in buildings.

Wind power has many advantages: It causes absolutely no pollution whatsoever. It consumes no fuel and has practically no effects on the environment at all. Wind energy can help generate tonnes of megawatts of electricity. When employed at home, it can help do away with conventional power sources which will reduce your electricity bill and can even eliminate it altogether. Wind power is an excellent source of continuous, renewable energy.

Finally, let's look at solar energy.

Solar power is by far the most available source of continuous, renewable energy on the planet. It is easily capable of providing the world's total current energy demand many times over. Solar power solutions at home are another way of dramatically cutting down power bills or even completely eliminating them altogether. Also, solar power has no effect on the environment whatsoever. It is the most environmentally friendly source of energy in the world.

Thursday, December 17, 2009

A study on Activity of Titas Gas Transmission & Distribution Company ltd. (TGTDCL), Bangladesh( Part-4)

2.5.5 Operation [10].
Inspections of operational works are:
 Co-ordination of pigging programs
 Cathodic protection readings
 Foreign crossing inspections
 Daily reading as required
 Co-ordinate R. O. W. surveillance

2.5.6 Maintenance and repair [10].
 Pump and compressor preventive maintenance and repair
 Pipeline repairs
 Valve maintenance and repair

2.5.7 Inspect the pipeline integrity programs 

Pipeline integrity programs are very important part of both pipeline operation and maintenance procedures. There are several functions that are required to form a complete pipeline integrity program, such as:
 Schedule pressure testing programs
 Annual river crossing profiles
 Pipeline coating assessment programs
 Depth of cover surveys
 Internal inspection surveys [10].

2.5.8 Inspection the Preparation for Welding

Safety regulations require the welding operation be protected from weather condition that would impair the quality of the welding. Before beginning the welding, welding surface must be clean and free of any material that may be detrimental to the welding. Also, pipe sections must be properly aligned for depositing the root bead. Specifications require that carbon steel with carbon content in excess of 0.32% must be preheated for welding. In some cases; steel with lower carbon contents must also be preheated. When steels with different preheated temperatures are being welded, the higher preheat temperatures must be used to weld the seams. Preheat temperature must be monitored to ensure the proper temperature and maintain that temperature during welding.             

Qualified trained welders must be employed for welding operation. TGTDCL has it’s own welder grades specified as Titas grade-A, B, C.  For high pressure pipeline a welding procedure specification (WPS) is established and suggest to follows these procedure strictly. Welding conducted as per the welding procedure and must be tested to ensure the WPS requirements fulfilment. Welded joints are inspected visually, mechanically and by using non-destructive test (NDT) methods. Mechanical test includes tensile test, nick break test, macro tech test, etc. Test results are to be documented and record the procedure of welding operation [1-2].

2.6 Inspection and Testing

Pipeline welds must be inspected visually to ensure the performance in accordance with the welding procedure and the welds are acceptable under the appropriate specifications. In the United States, to comply with provisions of 49 Code of federal regulation (CFR), non-destructive testing is also required on welds made on a pipeline that will be operated at a pressure that results in a hoop stress of 20% or more of the specified minimum yield strength (SMYS). There are two exceptions to this non-destructive testing requirement. Non-destructive testing is not required even though hoop stress will exceed 20% of SMYS if
·         the pipeline has a nominal diameter of less than 6 in.
·         the hoop stress will be less than 40% of the SMYS and the number of welds is so small as to make such testing impractical.
Non-destructive testing must be performed according to written procedures by specially trained personnel.

Radiography (X-ray) is the most widely used method for testing pipeline welds in non-destructive method. In radiography, a picture is made on a sensitized film by exposing the film to X-ray. Defects in the weld, such as cracks, porosity, or slag inclusions, appear as spots or lines on the developed film.

A study on Activity of Titas Gas Transmission & Distribution Company ltd. (TGTDCL), Bangladesh( Part-3)

2.5 Standard Inspection Methods:

2.5.1 Material procurement inspection
2.5.2 Visual inspection
2.5.3 Design inspection
2.5.4 Construction inspection
2.5.5 Operation
2.5.6 Maintenance and repair
2.5.7 Inspect the pipeline integrity programs
2.5.8 Inspection the Preparation for welding

2.5.1 Material procurement inspection
During pipeline construction materials are inspected visually and mechanically for their physical, dimensional defects and design accuracy. Materials are pre-qualified / inspected as per international standard during procurement [1].
The most common standards are:
 American Petroleum Institute ( API )
 American National Standard Institute ( ANSI )
 American Society of Mechanical Engineers ( ASME )

2.5.2 Visual inspection
Visual inspections are important in welding jobs for construction of pipelines. Cracks, incomplete penetration, burn-through, undercut, unequal leg length, and other imperfections in the test welds shall be assessed in accordance with the applicable requirements. Undercuts adjacent to the final test weld bead on the outside of the pipe shall not exceed 1mm in depth. The test welds shall have a neat appearance. Imperfections detected by visual inspections must be into consideration and take corrective measures.

2.5.3 Design inspection
The requirements for design inspection of pipeline construction project are:
 Fluid flow capacity
 Design pressure for each segment of pipeline system

°                       External pressures and loadings
°                       Ambient influence
°                       Temperature
°                       Location of Class
 
2.5.4    Construction inspection
Inspection of pipeline construction based on:
°                       Pre-construction activities
°                       Construction activities
°                       Post-construction activities

Pre-construction activities
Inspections of pre-construction activities of pipeline are as follows:
°                     Route selection
°                     Legal surveying and land acquisition
°                     Pipe hauling
°                     Equipments and vehicles

Construction activities:
Inspection of construction activities is very important for pipeline operation and integrity. When any pipe manufacturing defects are detected during installation inspection, the defective portion of pipe shall be repaired by the applicable pipe manufacturing standard or specification or cut out as a cylinder or where necessary replaced with another pipe that meets the design requirements. Inspection shall be performed by the experienced personnel. Inspection for piping defects shall be indentified immediately prior to the application of any field coating and during lowering in and backfilling operations. Pipe and component shall be inspected for defects. Such inspection shall include but not necessarily be limited to inspection for flattening, ovality, straightness, pits slivers, cracks, gouges, dents, defective weld seams, and defective field welds. Bends shall be inspected for conformance with the free from buckling, cracks, and other evidence of mechanical damage. Where the pipe is field coated, inspection shall be carried out to determine that the cleaning/coating machine is not creating defects in the pipe. Coating shall be inspected immediately before, during and after pipe installation. Faults in the coating shall be repaired and re-inspected. Plant-applied coatings shall be inspected immediately after field-bending to confirm that the integrity of the coating has been maintained. Where applicable, each pipe shall be visually inspected prior to welding for defects in its lining. Inspection of field and shop welds is in accordance with the applicable requirements of clause 7 [9]. Inspection of pipe portion repaired, replaced, and altered shall be made before it is backfilled. Where necessary and as appropriate, non-destructive inspection of piping shall be performed using one or more of the following methods:
(a)        Radiographic inspection of welds in accordance with the applicable requirements of clause 7.
(b)        Ultrasonic inspection of welds in accordance with the applicable requirements of clause 7.
(c)        Ultrasonic inspection of pipe
(d)       Electrical inspection of protective coating
(e)        Inspection using internal inspection devices and
Other methods are below:
°                     Stringing pipe
°                     Welding
°                     Coating
°                     Ditching
°                     Crossing
°                     Lower-in
°                     Backfilling
°                     Compression and pump station
°                     Pressure testing
°                     Clean-up and restoration    [10].

Post-construction activities
After the pressure test has been completed, it is then necessary to displace the test median from the pipeline and purge the system with sweet natural gas or an inert gas such as nitrogen to make the system ready for operation.


A study on Activity of Titas Gas Transmission & Distribution Company ltd. (TGTDCL), Bangladesh( Part-2)

2.2.2 Equipment and Vehicle Inspections

All equipments and vehicles should be thoroughly inspected daily or weekly basis by the operators to monitor wear and tear. If more than one person is responsible for the equipment or vehicle operation, responsibility for inspections should be assigned to the authorise person or group.

General checks like fluid levels, belts, hoses, and electrical connection; should be checked before operating of the equipment or vehicle. This type of inspection is commonly called a walk-around or ‘pre-use’ inspection.

2.3 Checklists of Company Inspection

To ensure the company’s inspection procedures through checklists should be used. Checklists help to guide (direct) the inspector and ensure him / her nothing is missed. In addition, checklists create a detailed record of the findings from inspection and suggest corrective measures.

2.4 Government Inspections

Safety in worksites and safe work practices must comply with regulatory requirements by the state. Occupational health and safety inspectors are the authority from the government responsible for safe worksite. Government inspectors are the useful sources regarding the safety standards status about a company. The prime objective of government inspection is to meet the government safety standards, to make worksites safe and advise on safety issues on the worksite where needed..

For this reasons, government inspectors may assess record, plans, policies, equipments or work procedures. The inspectors may interview the company personnel about hazard, risks, health and safety measures.

Procedures include in inspection:

 °        Before joining, of the prepared ends of the pipe and couplings for cracks, dimensional imperfections and detrimental mating surface conditions


°          The external surfaces of the completed joint for cracks and dimensional imperfections
Inspection personnel should receive training in the following topics :
°          The principles of the joint design
°          The function of the end preparation and joining equipment
°          The inspection procedure and applicable inspection methods
°          The end preparation and joining procedure
°          Know and follow standard work procedures
°          Properly use tools and equipment
°          Know emergency response procedures
°          Properly supervise and direct workers under their supervision

  Table-2.1: Quality assurance table with inspection schedule. 
 
No.
                   Activity
1
2
3
Comment
1
Material test reports

x
x
  Conform to                 material specification
2
Welding procedure

x
x
Examined 100% No laminations shall exceed ¼ inch
3
Welder qualification report

x

Certificate
4
Workmanship, dimensions
x


Visual
5
Material quality
x
x
x
Mill certificate
6
Radiographs/ultrasonic
x
x
x
Pressure piping welds shall be 100% X-rayed. Major structural welds shall be ultrasonically tested.  
7
Hydrostatic tests
x
x
x
Test report
8
Function tests
x
x
x

9
Protective coating
x


Visual
10
Preparation for shipment
x


Visual
11
Nameplate/tagging
x


Visual

 
Legend of the table
 1          witnesses or verification
2          Checks certificates and Records
3          Contractor provides certificate and/or test document and records. 







Seismic Energy Dissipation Devices

Seismic Energy Dissipation Devices