Types of Coal Storage Sheds

During the storage of coal many challenges arise such as spontaneous combustion of coal, loss of GCV (gross calorific value) and fugitive dust emissions. Due to rise of these kinds of problems there is a significant monetary and environmental loss. Coal storage sheds are considered as the perfect solution to overcome the challenges. With the help of coal storage sheds, these problems can be eliminated easily without damaging the environment. There are 2 types of Coal storage sheds-

1. COAL STORAGE - BARREL VAULT SHED

In this case, coal storage will be formed by the conventional rail mounted stacker cum reclaimer machines will be covered within the shed. The length and span of the shed could be adopted depending on the quantity of the storage required. In case of future expansion the length of the shed can be increased and same stacker reclaimer can be used for higher volumes. 

2. COAL STORAGE - DOME SHED

In this type of structure, the shape of the shed will be in the semi hemispherical form. There will be a concrete wall up to a certain height from the ground level and the structure will be erected above this wall. The dome structure of various sizes could be adopted depending on the quantity of storage required. A circular stacker and scraper type reclaimer could be used for reclaiming the coal. With this type of shed, coal will protected from wind and rain and hence the problems associated with these will be avoided. This kind of storage shed can accommodate higher quantity of coal in a smaller area as the height of storage could be increased. 

About Hindustan Alcox

We at Hindustan Alcox are the leading coal storage shed manufacturer in India. We provide practical solutions to these above challenges, in most efficient and cost reducing ways to provide our clients with the best available solutions in storage and handling of any type of bulk storage.

Read More - Impact of Open Coal Stockpiles 

Impact of Open Coal Stockpiles

Majority of the coal stockpiles inside the Indian power plant are open type built with various kinds of stackers and reclaimers. This type of open storage poses both environmental and functional loss. There are several problems being faced with the present type of open stockpile system.

Functionality loss-

1) Combustion of Coal – Spontaneous coal combustion in open storage is one of the major concerns in the thermal power plant. The spontaneous combustion of coal in the open stockpile results in the degradation of the coal and causes changes in the physical and chemical properties of the coal.

2) Loss of GCV – Coal loses the gross calorific value when stored in the open. This increases the amount of energy required per unit

.

3) Loss of Coal – 2.4% of coal goes to waste due to erosion by wind and percolation of the coal during rainfall.

Environmental loss-

1) Fugitive dust nuisance from the stockpile due to the wind – Due to the fugitive dust emission from the stockpile, dust particles will be carried by wind and causes pollution. This would pollute the plant area and could cause damage to the other utilities like cooling towers, switch yard etc in the power plant.

2) Ground Water Contamination – Percolation of the coal particles with the rain water contaminates the ground water.

In view of the problems faced in the open type stockpile, there are many alternative methods of storing the coal but Coal Storage Sheds are the best possible solution to address the issues listed above. Coal Storage sheds is highly specialized and comes with following advantages. The cost of structure is 30-40% lower as compared to other conventional structures. This structure installation does not impact the productivity of the plant. Since this structure uses circular sections that coal dust accumulation is kept minimal on the members.

About Hindustan Alcox Limited

With over 30 years of experience in it, we at Hindustan Alcox Limited are the leading Coal storage shed manufacturer in India. We provide practical solutions to these above challenges, in most efficient and cost reducing ways and satisfy our clients with the best available solutions in storage and handling of any type of bulk storage.

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Gasification of Coal

Gasification of coal is a high temperature process which is developed to produce a fuel gas with minimal of liquid and solids. Coal Gasification take place in a gasifier, generally in a high temperature vessel where oxygen and steam directly contracted with the coal causing a series of chemical reactions to occur that convert the feed to syngas and ash. Syngas is composed primarily of the colourless highly flammable gases carbon monoxide (CO) and Hydrogen (H2).  Coal Gasification is considered as a partial oxidation process.

Applications of Coal Gasification:-

¨ One of the most abundant energy sources

¨ Can be used to produce ultra-clean fuel

¨ Leading source of electricity today

¨ Chemical Production (Methanol, ammonia, acetic acid etc)

¨ Hydrogen made from coal or other solid fuels can be used to refine oil, or to make products such as ammonia and fertilizer (urea).

¨ By product of burning (ash or slag) can be used for concrete and roadways

Gasification is attractive for its simple but brutal operation. Higher efficiency, cleaner output and more control over products can only help the economics. As other sensor technologies are introduced gasification could be a leading refining technique for a wide range of raw materials from trash to cultivated biomass and on to coal. Gasification might not be elegant – but the process enjoys the leading spot for going to commercial scale in today’s market for synthetic fuel process. Particularly in clean generation of electricity from coal, gasification may make an increasingly important part of the world’s energy and industrial markets.

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Keys To Proper Coal Storage

Coal storage and handling is a common challenge faced in Thermal Power and Captive thermal power plants. In order to ensure safe and efficient coal storage, special attention shall be given to the following guidelines: 

Simple Step for Coal Storage:

• Coal storage shed is the finest possible solution in recent times for coal storage as it protects the coal from rainfall and spontaneous combustion thereby maintains the Gross calorific Value hence improving the plant efficiency.

• Another step in preventing spontaneous combustion is to take preventive measures. The coal stockpile should comply with principles of Proper stockpile management; packing it in horizontal layers, followed by levelling and dozing at continuous intervals.

• Sealing stockpiles is another effective way to prevent these kinds of coal storage problems and ensure that they comply with the demanding regulatory requirements.

• When the coal is not being used, it should be observed for rising temperature and gas levels. With routine observations, you can ensure the temperature of your stockpile remains around 50 degrees Fahrenheit and well below 70 degrees Fahrenheit.

Crucial measures are required to assure proper maintenance of the coal stockpile in order to run an efficient, environmentally-friendly coal plant. Improper Coal Storage can reduce the coal quality significantly primarily due to loss of gross calorific value and material loss.

The prime objective of coal storage is to reduce loss by preventing spontaneous combustion and minimizing coal loss. Spontaneous combustion occurs in coal piles when low-temperature oxidation slowly heats up the material to a volatile point. Spontaneous combustion can cause:

•          The decrease in Calorific Value

•          Fire, if the temperature exceeds the critical value

•          The decrease in Carbon and Hydrogen content and an increase of Oxygen %

ABOUT HINDUSTAN ALCOX

Over the last three Decades, Hindustan Alcox is an industry leader in manufacturing coal storage sheds. We identify and eliminate unnecessary energy losses from the processes by providing the best choice for covering coal under storage shed.

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Coal Gasification: Best practice to generate clean power from coal

Coal Gasification:

Coal Gasification is a process that can turn coal into clean power, chemicals, hydrogen & transportation fuels that can be further used to generate electricity or steam. These coal gasification systems are introduced in captive thermal power plants with advanced technologies to reduce the cost and increase the efficiency.

Coal Gasifiers convert hydrocarbons into a synthesis gas (syngas) at elevated pressures & temperatures and can be used to create many products such as electric power, chemical feedstock, liquid fuels, hydrogen, synthetic gas.

Why Coal Gasification is best practice to generate clean power from coal storage?

Coal Gasification is usually considered as best practice to generate clean energy from coal storage. The aim of coal gasification is to generate power which is an important consideration in the future of hydrogen fuelled electricity generation.

                        Providing numerous opportunities for pollution control, especially with respect to emissions of sulfur, nitrous oxides, and mercury, coal gasification also increases the resource availability for power generation. Followings are the main advantages that persists with a coal power plant integrated with coal gasification:-

·Environmental Performance

·Maximizing power or efficiency

·Long life

·Reduced Volume of solid wastes

·Free from dust & noise pollution

          With long-term experience of 30 years, Hindustan Alcox Limited identifies and eliminates unnecessary energy losses from the processes by providing the best choice for covering coal stockpiles under Coal storage shed. Alternatively, Coal Storage and handling can also be done under dome structure sheds (like Coal dome, petcoke dome).

- Hindustan Alcox Limited, New Delhi

  (Coal Gasification - Specialist)

Coal Storage Domes integrated with Coal Gasification: An Ideal Storage Solution

Coal Storage:

For a fruitful outcome of thermal Power Plants, the business of industrial coal storage for large quantities is on top priority for maintaining the product Integrity. Open stockpiles leave materials subject to degradation during storage. In addition, there are environmental concerns with controlling dust and runoff from these coal stockpiles.

Coal Storage Domes integrated with Coal Gasification:

Conversion of coal by the chemical processes to produce a mixture of combustible gas or fuel gas or syngas is termed coal gasification. Coal Gasifiers generally entails the controlled oxidation of the coal to convert it into desired gaseous products. The emphasis of coal gasification is to meet stringent emission control requirements.

Bulk storage dome structures are highly durable and strong. If we talk about strength and average building life of dome structures, then their life is longer and strength is more than any other type of stacker reclaimer sheds in Space frame industry. Coal storage domes with coal gasification has its own advantages. These include:

• Simple foundation requirements.
• Rapid construction regardless of weather.
• Condensation is virtually eliminated.
• Better environmental and fugitive dust control.
• Environment Friendly.

Dome Structural system provides a unique solution to the bulk storage industry. Remained committed towards sustainability and improving the local economies, the coal dome manufactured by Hindustan Alcox Limited are strong, durable, environmentally sound and adaptable. Over Last 20 Years, Our capabilities as a "prime industrial shed manufacturer" include building the Bulk storage dome shell for providing turnkey solutions all over the world.

• Hindustan Alcox Limited, New Delhi
  (Coal Storage Sheds Manufacturer in India)

Coal Storage: Performance Requirements for Maximum efficiency

Coal Storage:

Coal is a fossil fuel just like oil and natural gas. In thermal power plants, coal storage or petcoke storage (as the most exploited solid fuel) at large scale is preferred for the production of electric energy. A good preparation of coal before its combustion increases the homogeneity and efficiency of the fuel, reduces transportation costs and its displacement inside the plant produces less dust and reduces the emission of sulphur oxides. Besides, Preventive measures should be taken at every stage during the transport and bulk storage, in order to reduce any environmental impact, so that it became easier to maximize plant efficiency without any interference of any outside or environmental effects.

Performance Requirements for Maximum efficiency:

The large investment in a thermal power plant should be protected in best pos­sible way by maintaining the quality of resources (like coal, petcoke, lignite etc) and by uplifting the performance of their handling system. The coal handling system and equipment should perform satisfactorily to meet the guaranteed performance for maximum efficiency as stated here under:

1.      Efficient operation in thermal power plants means the careful use of fuels and other consumables resources includ­ing in-house consumption of electricity. High availability requires strong focus on maintenance, which in turns contribute as one of the factors in producing maximum efficiency.

2.      Stacker or reclaimer should be stable under a specified design condition and meet all the specified requirements. During unfavorable environmental conditions, the stacker or reclaimer should reclaim the coal in a way to avoid generation of well compacted, damp and sticky coal.

3.      Sulphur content in fuel always had an adverse effect on overall plant efficiency. ‘Corrosive acids formation’ and ‘heat loss in boiler’ can be evaded by properly supervising and removing the sulphur content in coal.

4.      Condition based maintenance uses intelligent measurements and assessments. These can include oil quality, differential pressure measure­ments, vibration readings and many more. By such applications, maintenance and renewal of plant components can be done exactly when needed.

5.      Fuel quality of coal, which is generally quoted in terms of its gross calorific value (GCV) along with its moisture and ash content impacts on whole plant operational efficiency. Assessing fuel quality and choosing fuel of maximum gross calorific value and less moisture & ash content improves combustion and power generation as well.

6.      Variation in the ambient temperature tends to affect plant performance and load capability of gas turbines along with the performance of cooling system. Hence, it is better to maintain the ambient temperature near a specific threshold during plant operation for maximum power output.

Using long-time experience of 30 years, It has been challenge for Hindustan Alcox Limited to identify and eliminate unnecessary energy losses from the processes by providing the best choice for covering coal stockpiles under Coal storage shed. Alternatively, Coal Storage and handling can be done under dome structure sheds (like Coal dome, petcoke dome).

  

--   Hindustan Alcox Limited, New Delhi

(Coal storage Shed Manufacturer)

Handling & Maintenance of Petcoke Storage in Captive Thermal Power Plant

Storage of Petcoke­: 

Coke is a fuel made from coal with high carbon content and few other impurities. Petcoke (or Petroleum Coke) is fuel derived from its oil refining. The captive thermal power plants exploit chemical energy of the petcoke and convert it into into electrical energy. That is why maximum requirement of fuel in thermal power plants is of coal. The petcoke storage at a large scale is needed to deliver in the storage yard through transportation. The modes of coal transportation include railroad, pipeline, barge, truck, and conveyor for domestic movement, plus ship movement for overseas. Then the petcoke is dropped in a coal yard and usually stored in stockpiles. The Petcoke Storage plant in a thermal power station covers unloading, its crushing, storage and filling of boiler bunkers.

Risks to petcoke/coal storage & their proper handling in Thermal Power Plant:

Global warming and other environmental factors such as oxidation at low temperature, microbial metabolism, absorption & desorption of water by virtue of differences between real and equilibrium moisture content in coal and air causes some risks to coal storage. These risks include ‘self oxidation of coal’, ‘increase in moisture content’, ‘spontaneous combustion’, ‘flow blockage’ etc.

In a Captive thermal power plant, the foremost and effective process to avoid the risks to coal storage in the power generation is “Coal Handling”. Coal handling includes bunkering of coal, stacking & reclaiming of coal. Giant Stackers may be used to form two different patterns- ‘cone’, ‘chevron’ either on one or both sides of stacker.  Stacking and reclaiming of coal is not only limited to avoid risks (such as spontaneous combustion,  self oxidation, caking problem) to coal stockpiles but it must be carried out in such a way to keep coal effective to feed the boiler and in turn optimized power generation.

Maintenance of petcoke/coal stockpiles for Productive Outcome Power:

Besides the proper storage and handling of coal up to a remarkable extent, the maintenance of coal stockpiles for long term use play an crucial role by resulting an optimized power production.  Maintenance of coal stockpiles for Productive Outcome Power can be upheld by considering the following points:

·        Coal dome or Petcoke dome should be constructed in such a way to prevail cross ventilation at every corner inside it which, can be done to prevent heat accumulation as well as to maintain the quality of stockpiles for a long term. Besides, Coal dome provide best protection against moisture and rainy weather since coal is vulnerable to moisture.

·        Monitoring height and orientation of stockpiles: Routine surveying of stockpiles in term of their heights and orientation should be done using infrared devices and/or sensors where spontaneous combustion is more likely to occur. Storing coal in form of many smaller stockpiles is a great idea.

·        Autonomous Stacking & Reclaiming: The coal can be stacked and reclaimed by various methods like (windrow, chevron, cone-shell etc) in order to provide an adequate treatment to the material as well as the long-term maintenance of coal stockpiles for efficient power outcome.

·        Coal Quality Management:  The system of coal quality management is equally important while maintenance of coal stockpiles is our priority. To examine coal quality, the parameters like (calorific value, density, ash content, moisture content) are the prime.

·        Material Tracking:  The enhanced degree of efficiency of modern coal power plants calls for an integrated coal material tracking system in order to secure the coal supply in the requested quantity and quality. For an efficient material handling system, the Coal should be traceable anywhere, even in a surge bin, on a belt or on the stockpile.

Hindustan Alcox Limited, the well-versed & proficient organization emerged as India’s apex coal storage shed manufacturer holds a tremendous experience of over 30 years in producing Coal domes & storage sheds. Depending on different factors like geology, demographics, climate etc we provide the best feasible & competitive Bulk Storage dome solutions such as Petcoke dome and Coal dome.

-          Hindustan Alcox Limited, New Delhi

(Coal Storage Shed Manufacturer In India)

Role of Coal Gasification In various industries

Introduction to Coal Gasification / IGCC technology:

IGCC stands for “Integrated Gasification combined cycle”. The preliminary conversion into a gaseous fuel originated is named as SynGas / Synthesis Gas. Synthetic gas is an intermediate source for generation of hydrogen, ammonia, methanol, & other synthetic hydrocarbon fuels. For electricity generation, synthetic gas is not only used as fuel of internal combustion engines due to its combustible nature, but also plays an important role in keeping the plant eco- friendly.

During Coal storage at a large scale, for harnessing coal's energy more cleanly and efficiently, a number of different ways attempted in order to motivate environmental concerns. Among them, the technology comes out to be most successful is ‘coal gasification’, where instead of burning the fossil fuel, it is chemically transformed into synthetic natural gas or syngas.

What is the Need:

Till now, the main objective of Conventional Thermal Power Plant was to increase the efficiency by means of increased temperature and pressure in the steam, which in turn generate an efficient power outcome. But today theneed is to get more efficient power production along with keeping the outside eco friendly. With the technical advancement in working methodology, the upgraded thermal power plants are now capable to generate power using Coal Gasifiers in purpose to increase efficiency of the plant.

Advantages of using the Coal Gasifiers:

·        Clean Energy Conversion:From an economic and energy security perspective, coal gasification is proved themost successfulprocess to dealt with clean energy conversion, since instead of opening the intermediate poisonous gases up to exploitation, coal gasification helps to access these resources cleanly.

·        Environment Friendly:Addressing the atmospheric problems resulting from burning coal and getting least affected by these poisonous gases is one of the top priority objectives of coal gasification. This Enviironment friendly feature of coal gasification is also thekey to achieve near-zero emissions from gasification-based power generation.

·        Enhanced Power Generation& Reduced Resource Consumption:In coal based thermal power plants, synthetic gas collected during the coal gasification is used as fuel of internal combustion engines due to its combustible nature, which in turn not only participate in enhancing power generation but also reduces the resource consumption.

·        Easy Installation and Maintenance: Coal Gasifiers, whichare the main source to carry out coal gasification are installed in conjunction with coal bunkers. As far as their fixing and maintenance is concerned, these coal gasifiers are very simple to install and to maintain for the long term.

To supplement the eco friendly nature of the energy, Hindustan Alcox Limited provides world-class structures to cover spans up to 150m and any length. These sheds provide economical solution for such storage needs.

-         Hindustan Alcox Limited, New Delhi

(Coal storage Shed Manufacturers in India)

Coal Storage: Problem of Spontaneous Combustion & Its Prevention

Coal, a non-renewable combustible material composed of carbon and hydrocarbons, whose combustible quality can be used for electricity generation and for some other necessities. Although stacking of coal is done in open shed areas, there are also covered shed areas or completely closed coal dome or silo.

Spontaneous Combustion of Coal ?

Spontaneous combustion of coal stockpiles

Many issues have been encountered in bulk storage but in case of storing coal, self-combustibility comes as a special case & need careful treatment. The Spontaneous Combustion of coal in the coal storage is serious issue now a days due to global warming and other exothermic processes in coal stockpiles such as microbial metabolism, oxidation at low temperature, absorption & desorption of water by virtue of differences between real and equilibrium moisture content in coal and air. Spontaneous combustion usually begins as "hot spots" deep inside the coal/petcoke storage. They appear when coal absorbs oxygen from the air & heat generated by oxidation initiated the fire.

Key Causes of Spontaneous Coal Fires

The risk from spontaneous combustion or coal fire persists where significant amount of coal are in use or storage. The following mentioned points have been the contributing causes of spontaneous coal fires:

·        New piles of coal added on top of old coal stockpiles creating segregation of particle sizes and become the major cause of heating.

·        Too few temperature probing techniques or sensors installed in bunkering of coal resulting an extension in the time period before the fire was detected.

·        Equipments’ failure to fight the coal fires (such as drag chain conveyer).

·        Ineffective use of “Carbon dioxide fire suppression system” in plant area

·        Delay in the application of water.

·        Inadequate training of personnel, improper implementation of policies, & procedures prevented proper decision-making, including the knowledge to immediately overcome the coal fire.

·        Long-term retention of coal in coal handling procedures also increases the probability of increase in temperature.

Preventing  Spontaneous Combustion in coal stockpiles-

Preventing spontaneous combustion involves attention to many different factors, are as follows:

·       Sulphur in coal liberates ample heat when they oxidize. Hence, strategies like “Know your Coal” & “Storing coal with low sulphur content” are helpful in evading spontaneous combustion in the plant area.

·       Air circulation within a coal stockpile should be avoided up to possible extent since this supports increase in temperature in the stockpile.

·       Use coal as quickly as feasible. The longer large coal stockpiles are allowed to sit, the more spontaneous combustion process dominates and increase the chances of coal fires.

·       Do Proper inspection, test & maintenance of installed fire protection equipments on site.

·       Following the "first in, first out" rule in coal stocking and stacking under petcoke dome or storage shed reduces the chances for hot spots in stockpiles by dissuading heat buildup for portions of stockpiles, which remain undisturbed for a long term.

-         Hindustan Alcox Limited, New Delhi