It doesn´t matter if the technology used is batch or continuous; inefficiencies can only pull the profitability down. EQUIPMENT INDIA tracks the developments in the asphalt plants.
Globally, the past decade saw amazing developments in the hot- mix production technology. In India too, with the entry of global players, OEMs have geared up to offer advanced plants that can produce a variety of mixes - be it low energy / low-temperature asphalt mixes, warm / cold mixes, high percentage RAP mix, high recycling technology. However, In India the adoption of these advanced technologies which could conserve virgin resources, bring down carbon footprint, and considerably reduce fuel consumption and thereby, lower production costs.
According to Blesson Varghese, Managing Director, Marini India, inefficiency cannot be tolerated at any level - be it measuring, thermal conservation or production. We lose a lot of our profits to inefficient thermal designs, inaccurate weighing and gradation, due to amateur processing and technologies.
The process is same, it is the final quality of mix and operational sustainability that matters the most. European countries allow higher permissible axle loads on their roads and follow the most stringent norms, use continuous technology, while in India it is a different story. Varghese says, ´In India the continuous plant technology has been so much diluted and never been upgraded. If supplied with good controls and sensible technology, it could work wonders in terms of sustainability and to meet the raising demands in the country.´
Sunil Sapru, Chief Executive - Marketing, Ammann Apollo, adopts a different angle to the concept of plant efficiency. According to him the equipment cost is negligible, less than five per cent of the project cost. It is not the equipment cost that matters, but the equipment performance / efficiency, which delivers much better sustainable mix quality. Sapru says, ´Inefficiencies will not only pull the profitability down for the developers but will also result in poor quality of roads.´
According to VP Mundra, Director, Basic Engineering Equipment, the area of improvement in a batch mix plant is on the mechanical part of the equipment, the process remains the same. Globally the drive is to reduce paving temperatures which is achieved by chemicals additives in mix designs. When you bring down the temperature, you save fuel. So technology is nothing to do with the plant, but with the mix design.
Multiple fuel options & fuel efficiency
What would be the estimated fuel consumption per tonne of asphalt produced by using different fuels? Varghese says, ´Marini´s are equipped with real multi-fuel options. A good example is when a decade old Marini which was relocated near the Taj Corridor in Agra had to be upgraded to gas firing. This plant was supplied with a diesel / heavy oil / LDO combination along with a gas option. Within days of request our technicians changed over the fuel from diesel to natural gas, without any change in the burner or control system. Marini has developed a new generation multi-fuel burner especially for Indian operations. Some of these burners have already been supplied and are being used by our users,´ he adds. According to him fuel consumption depends on numerous site variables and inputs. ´The recent plants, with latest combustion technology have clocked as low as 3.2 ltr/tonne. The technology we have implemented when compared easily delivers anywhere between 25-30 per cent saving in fuel consumption, which is easily verifiable by our end users,´ Varghese says.
Ammann Apollo offers the fuel options of heavy oil, light oil, natural gas and coal. The actual consumption largely varies with the type of aggregate, moisture content, calorific value of fuel etc. Sapru comments, ´High efficiency drier and burner design ensures better fuel efficiency and cleaner exhaust gas. Larger capacity storage in material silos gives higher buffer for continuous production. Better mixer technology ensures lower wear parts costs and faster batch mixing. In line storage silo for hot mix ensures faster truck loading and provides buffer storage to keep the plant running at optimum capacity and no waiting time for next truck. Upgraded control software for more accurate weighing. Provisions to use recycled asphalt results into cost savings.´ He adds, ´On an average the fuel consumption is around 4.5-5 liter. At the same time, we have achieved a fuel consumption of 3-8-4.1 ltr for our plant supplied with Ammann design and burner.´
´We use compressed air atomised burner in which we inject six kg pressure of air to the compressor along with fuel so that there is an easy atomisation and there is no chance of any un-burnt fuel getting into the drier,´ says Mundra.´ Speco uses its own patented burners for which one can use fuels such as furnace oil, LDO, HSD, etc. If somebody wants to use gas as fuel, then one has to use gas burner. However, handling gas is a tough task at the production site due to complications in storage and handling. In India, the plants move from one place to another and setting up storage facility for gas cost huge amount of money and so is not practical to use it as fuel in batch-mix plants in India. Mundra says, ´Customers have now started using coal as fuel. Coal burners are good provided the quality of coal is good but again setting up storage facility at site is cumbersome. So, the overall cost in transportation of coal, storage at site and crushing to fine powder is huge compared to furnace oil.´ Bhavesh Patel, Proprietor, Atlas Equipment says ´Our range of plants which we have sold so far, have an average fuel consumption of 4-4.5 ltr/tonne. This range varies according to moisture content, dust, etc.´
Advantage plant configuration
The plant configurations play an important role on how the customer will face his future challenges. Sapru says, ´One significant change in plant configuration that we have made is replacing the cyclonic pre-separator to smartly designed deflector type. This reduces the raw gas flow path and thereby saves energy. This also makes it easier for erection of the plant.´
´Plant configuration is a very serious business at Marini. This explains why Marini´s have the highest variety of plant configurations in the market, since each customer needs a specific configuration to meet his future vision and market requirements,´ says Varghese. He adds, ´Based on customers´ needs and market trends, we configure the plant to ensure Marini´s users stay where they are expected, always at the top. A good example is the storage solution on the plant. Our solution offers multiple loading points, ensuring plant production never stops even for the need of maintenance. Cranes and material handling devices are required to be minimal, knowing that these come at a cost and are at dearth in India.´
However, according to Mundra there is only one type of plant. He says, ´If you are adding any recycled material, then you will need an attachment for the RAP material. That is the only additional feature. If you are using only virgin materials, you know the material and you have a particular fuel to use. So the configuration will be the same. If you want to use multi-fuels like coal, gas, etc, then you can add a compatible burner.´
Most of the major suppliers have developed software customised to have better control of asphalt plants. Marini uses Cybertronic proprietary software developed and tried out in over 3000 asphalt plants around the world. With all processes available on a single window, the software combines the information that is needed during plant operations; both electrical and automation. The learner´s mode helps new operators to be trained on the plant with great ease. Auto-fault detection with direct on-board links to all the PLC processes helps easy fault diagnosis; maintenance module on the plant enables systematic maintenance of plant components; and the eco-energy module keeps track on all the energy consumption patterns.
Ammann Apollo has specially developed software customised to control the asphalt plant process in an optimised way. Says Sapru, ´We have two types of controls - PLC based and industrial PC based. We use special hardware modules for different processes to improve the response time of the controls. Our PC based software and control hardware provides nearly real time control for accurate control of temperatures, weighing cycle etc. We also provide SCADA and remote connectivity for data recording and analysis. Our latest software AS1 has many modules like energy monitoring, maintenance management, dynamic RAP control etc, which helps the operator to optimise the energy consumption of the plant, ensure proper preventative maintenance and easier use and control of RAP addition.´
Low energy/temperature mixes
On the global market OEMs have developed a variety of mixes such as low energy / low-temperature asphalt mixes which can well be adapted by road building fraternity. Sapru says, ´This is very much possible. Our proven foam technology enables production of warm mix with comparable quality of mix and road performance. This can result into several benefits - cost, lesser carbon foot print, reduced fuming of bitumen and cleaner paving site.´
However, Mundra has a word of caution. He says, ´It will reduce fuel cost but it will add to some cost of using chemicals to bring down the temperature level. You have to do a cost analysis in using the chemicals and find out what is the effective savings which is to be done by the developer or contractor.´
Upgrade of specs
The faster adoption of advanced technology is also dependent on how fast the specs are upgraded. The standards are only effective as much as they are enforced, and in a democracy real change can come only when people decide to do things the right way. It calls for a change in mindset. The government in recent times has been proactive in welcoming new methods and finding new ways. Says Varghese, ´We do not think that specifications alone have any power to drive any market demands. Since such kind of specifications which need a complete change in equipment might not be easy to implement in the country. However, new quality and performance based parameters would surely make road building professionals seek better quality delivery equipment.´ The authorities in MoRTH, NHAI and other government departments while emphasising on the speed of road building, should also give importance to the quality of roads being built. According to Sapru officials of MoRTH have regular meetings with the industry to upgrade the technologies. And Mundra supports the view stating that the government should strictly see to it that the specifications given in the tender are implemented.
It´s time to RAP
The awareness of the usage of RAP is limited to a few road construction companies. The cost of technology is also perceived to be a constraint though the payback is reportedly faster. The other reason could be the conservative approach being adopted by the users. Says Varghese, ´Removing restrictions on the limit of recycling and appreciating the professionals using these technologies, while making specifications purely based on performance parameters, will definitely make recycling popular while conserving India´s natural resources. Today, a number of professionals with very good technology are limited to use recycling, since the specs limit the percentages. According to Sapru processing of recycled asphalt and ensuring good quality of end mix requires proper knowledge and testing of the RAP. Awareness about the important parameters is the key to successful use of RAP. Says Patel, ´Government has already started working in this direction and there will be changes in legislation in using recycled materials. Probably this will be made mandatory in the near future.´
Plant type: In all the NHAI and major state highways projects use of batch type asphalt plants is mandatory. Now a few states have made the use of batch type asphalt plants mandatory in state road projects worth Rs 250 million. Continuous type of asphalt plants is used in state PWD projects, PMGSY, and in certain SAARDP projects. The demand for batch type plants will be higher than the continuous type plants.
Higher capacity plants: The capacity is dependent on the projects. Generally, the demand is for 120-160 TPH in the batch type plants and 60-120 TPH in the continuous type plants. Says Mundra, ´For state highways which are two-lane roads, in the case of a batch mix plant, every 70-100 km stretch one smaller capacity plant will be required to supply asphalt at regular intervals to pave the road. This will reduce the logistics cost and retain the quality of asphalt. But if there are highways of four lanes, six lanes or eight lanes, the bituminous asphalt requirement will be more and may require bigger size plants of 200 TPH and more.´ According to Varghese in India the capacities for the asphalt plants are not always guided by the demands of projects. The demands from upcoming projects might not really see a change in the capacities, since the investor mindset is not fully recovered from the slowdowns and most of the professionals are treading with caution.
With a huge network of roads to be constructed the demand for asphalt plants will go up. Despite the government has announced its plan to award hundred projects in rigid pavement, it will not have adverse impact on the expected demand. Opportunity lies in both flexible and rigid pavements. The global change in environment and economy is however now forcing us to look at sustainable development. Today more professional road- building companies are showing interest in producing high content RAP, warm- mix, low energy mixes, specification mixes, cold- mixes, etc. BOT projects have opened new doors to test globally proven technologies that benefit the producer, the user and are economically as well as environmentally. Use of alternative fuels, mix enhancing additives and sustainable practices are being welcomed and sought. The next decade of road construction activity in India will usher in the exodus from traditional methods to sustainable practices.
ADVANTAGES LOW ENERGY/WARM MIX ASPHALT
Ammann Apollo installed its first UG 260 S, a high technology, high output batch type asphalt plant in India in 2015.
Project: Varanasi - ShaktiNagar for six lane road of 113 kms of SH - 5a.
Duration - 36 months with extension. (8 to 9 months left to complete this project.) Plant site - Robertsgunj.
Requirement: 4 to 5 lakh tonne - Production till date is 94000 tonne
Customer view: Hukumi Chand Jain, Managing Director of Chetak Enterprises and Anil Singh, Managing Director of Apco Infratech are extremely satisfied. ´Purchasing UG 260 is the correct decision- we doubt whether any other plant would have delivered such results with zero downtime.