http://www.us-erc.org/greenchannel/nov2000/focus-cleanerbrick.php

By Arun Kumar, Geeta Vaidyanathan and K. R. Lakshmikantan

(Through changes in design features and operating procedures, environmental performance and product quality are being improved as the Vertical Shaft Brick Kiln (VSBK) technology, developed in China over the last three decades, is introduced at Indian VSBK sites)

India has a shortage of 18 million houses and a growing population currently in excess of 1,000 million. While the gap between supply and demand is widening, the present trend in building construction shows a perceptible shift to use of more energy-intensive materials.

The building materials industry in India is a major user of natural resources, energy, manpower and capital. The construction sector is the largest contributor of CO2 emissions, being responsible for 22 percent of the total. This sector is slated to grow continuously, with projected 4.6 percent annual economic growth, resulting in increased affordability and marked changes in consumption patterns. It has been established that the major energy users in the building materials industry are the producers of cement, bricks, steel and lime. Together they contribute 80 percent of total CO2 emissions from the Indian construction sector.

Current demand for these four materials requires energy amounting to 743 PJ, with a corresponding 81 million tonnes of CO2 emissions. In the specific case of cement, per capita consumption is expected to increase from the existing level of 60 kg to 210 kg by the year 2020. The latter figure is equivalent to current consumption in developed countries.

As these materials are largely material-intensive, their use puts increasing pressure on natural resources and on non-renewable energy resources. It is expected that, by the year 2020, their use will result in a threefold increase in energy requirements. The corresponding emissions will escalate to 285 million tonnes of CO2. These projections are based on current technology mixes prevalent in the respective manufacturing sectors.

Housing demand could be met, while limiting energy use and emissions to half the levels reached when conventional processes are used, through appropriate technological, process and institutional innovations.

The brick industry in India

Burnt bricks are the most popular building material in India. The present demand is estimated at 55 billion bricks per year. There is a resulting supply gap, which in the case of burnt bricks is the natural consequence of the limited energy resources and depleting clay resources. The normal response is to improve energy efficiency within the basic material production sector. This response is evident in the cement and steel industries, which are acquiring new technologies to achieve high standards of energy efficiency and environmental performance. Such a trend in the brick industry has been sadly lacking.

The brick industry is based on widespread production activity which is energy-intensive, resource-depleting and highly polluting. Problems in this industry have been exacerbated by cheap access to resources such as soil, water, coal, cowdung and biomass materials. Even though the industry is organised regionally and is controlled by powerful industry associations, the level of skill development is very poor.

Environmental regulations

In 1994, due to the highly polluting nature of brick kilns, the Supreme Court of India issued directions for kiln operators to change to cleaner production technology or face closure. The deadline for meeting new environmental performance standards was December 1997. In Agra, which is the traditional home of the world famous Taj Mahal, brick production activities have been totally banned as the emissions from brick kilns were damaging its structural integrity. The response to these directions was at first lukewarm. However, when the regulatory authorities threatened action if the directions were not complied with, a more positive approach was adopted by the operators nationwide. The brick kilns in Agra were forced to close down, while in other areas the search for solutions began in earnest. With the new environmental performance standards coming into effect in June 1999, a temporary reprieve was obtained by kiln owners. The response of the four major stakeholders is summarised in Table 1.

This response is from the organized sector of brick production. This sector is responsible for up to 60 percent of the national brick production. The balance production involves traditional clamps, which are structured geometrical stacks of green bricks (Figure 1). These bricks are fired 'in situ' using renewable fuel like wood, biomass and cowdung. Clamps are:

• Energy-intensive
• Resource-depleting
• Responsible for poor quality bricks
• A low-investment, high-risk activity and
• Highly polluting.

The general opinion is that the enforcement procedures would not be widely applicable to brick manufacture using clamps. This is due to the highly segregated nature of this activity, particularly in rural areas. Therefore no agency (including industrial organizations, regulatory bodies, academic institutions and independent sector organizations) has paid serious attention to the problems of clamp owners. The search for appropriate technology solutions led to the VSBK technology as a possible alternative.

Cleaner production technology

The most promising technology for decentralised production of burnt bricks was developed in China during the last three decades. The Vertical Shaft Brick Kiln (VSBK) technology has been developed on a large scale in China since construction of the first prototype kiln in 1958. Efforts to refine this technology have been made at the Energy Research Institute of the Henan Academy of Sciences at Zhengzhou. These pioneering efforts have resulted in recommendations on an optimum design, offering high energy efficiency, better quality brick production and high economic viability of production. Since 1989, the VSBK technology has been widely disseminated. There are some 50,000 of these kilns operating in China.

Advantages of VSBK technology

The main advantages of the VSBK technology are:

• It represents a very energy-efficient, low-cost method of firing bricks. The fired quality is high with very low wastage.
• The kilns require very little maintenance once constructed and are not complicated to build.
• The kiln is very compact, not requiring a large area of land, and can be built near the clay source. In China the kilns are  demolished and rebuilt using the same materials, as the clay source is depleted.
• The construction cost is low.
• The kiln is not affected by variations in weather as long as dry green bricks are available.
• The presence of more than one shaft allows for firing flexibility, to cope with seasonal and economic variations in brick production and demand.
• The kiln is highly suitable for use where fuel is incorporated into the brick.

Leading initiative

The initiative for cleaner and environmentally sustainable brick production in the unorganized sector coordinated by Development Alternatives, an independent sector organization (ISO), was launched to introduce the VSBK technology into India. After a fact-finding mission to Peshawar (Pakistan), the technical team concluded that the VSBK technology was perhaps mature enough to be introduced as a cleaner alternative to clamps. Upscaling was identified as a major area of research and development prior to introduction of the VSBK technology in the organized sector in India.

The first VSBK kiln set up in Datia, India by Development Alternatives achieved impressive results with average quality soil (Figures 2 and 3). The energy savings achieved in India are double those using the best practice technologies available for a conventional Bulls Trench Kiln (BTK). Energy consumption for production of burnt bricks using different technologies is as follows:

Burnt bricks (clamps) = 5-11.0 MJ/brick
Burnt bricks (BTK) = 4.20 MJ/brick
Burnt bricks (VSBK) = 1.98 MJ/brick

The VSBK technology, in its introduction stage in India, already demonstrated a potential savings of 120 tonnes of CO2 per million bricks produced. Specific emissions for walling options for popular materials are given in Table 2.

The techno-economic parameters of VSBK have been assessed in order to determine the market potential of this technology. With a capital investment of $11,000, it is possible to achieve an annual saving of coal amounting to 100 tonnes of coal for each kiln. The payback period is likely to be less than three years. The cost of mitigation, assuming the full capital cost is financed through commercial loans, would be $20 per tonne of CO2 (Table 3). The market conditions under which VSBK bricks are produced realize a product value of Rs 600 ($15) per GJ of energy input compared to Rs 120 ($3) and Rs 400 ($10) per GJ energy input in the case of clamps and Bull's Trench kilns, respectively.

Experience gained from the operation of the first few VSBK sites in India has been shared with potential entrepreneurs. The advantages perceived by associates who are external to the task force are:

• Low perceived risk during operation and in respect of financial investments
• Higher quality product for any given soil quality
• Uniformity of firing
• Simple technology to master.

Environmental performance

The original VSBK design, introduced by the Chinese experts, integrated aspects of cost-effective construction methods to achieve energy efficiency and economy of operations. The VSBK technology in China has paid scant attention to environmental performance and operators' health and safety.

The adaptive research and development undertaken by the task force has focused on overall improvement of the local environment and specific improvement in the workplace environment. The special measures that have been taken are in the design of bypass circuits for flue gases, operating cover for each shaft, and an elevated roof with monitor for facilitating ventilation of the workplace. These measures simultaneously allow for a cleaner workplace and prevent accumulation of noxious gases. Through a combination of design features and operating procedures, energy efficiency and product quality have been improved, along with environmental performance, at all VSBK sites in India. Comparison of environmental performance against prevailing standards is shown in Table 4. The environmental soundness of the technology will be validated in consultation with the State Pollution Control Boards.

Mechanism for multiplication

The institutions that can respond to environmental challenges and consolidate technology transfer are government agencies, the private sector and independent sector organizations. In India, the government agencies, along with the industry associations, are unable to break away from marginal improvements in conventional technologies. The private sector is not interested in investing in small scale, decentralized production technologies. The voluntary initiative of independent sector organizations is the only tenable solution. From the national perspective, the savings in energy are potentially higher for changing over from clamps to the VSBK technology than for marginal improvements in BTK.

The voluntary initiative for promotion of the VSBK technology in India is implemented by a Trans-Sectoral Multiple Stakeholder Task Force (Figure 4). The technology transfer has been facilitated by the Henan Academy of Sciences, China. Project implementation has been designed with the technical support of international consultants Soranne and SKAT.

The Indian technology promoters have been responsible for the pioneering efforts to indigenize the technology, with the coordination being provided by Development Alternatives. The industrial partners have been leading the upscaling of the technology and establishing economic viability under a variety of regional conditions. The task force has engaged partner organizations for successful demonstration of the technology in different regions having varying geo-climatic conditions, different soil and fuel combinations and varying market conditions.

At the inception stage itself, industrial partners producing burnt clay products have been integrated into the program for defining the high-quality brick production standards. A team of local and international consultants is leading the initiative to improve resources productivity and to widen the applicability of the VSBK technology to a wider variety of soils. Energy and environmental monitoring teams at all kiln sites have been engaged to ensure the reliability of the VSBK technology in terms of high environmental performance. Particular emphasis is being laid on achieving operational health and safety conditions, which are largely ignored at all kiln sites even in the organized sector. A pool of practitioners are being trained in all aspects of construction, operation and maintenance.

This multiple stakeholder initiative plans to engage national level regulatory bodies like the Central Pollution Control Board to validate the environmental performance of the VSBK technology. The Building Materials Technology Promotion Council (Government of India) validates the technical claims and economic viability of brick production through the VSBK technology. These are visualized as crucial stage for large-scale dissemination and meeting the long-term needs of kiln owners. The overall objectives of the task force are to guide the evolution of the VSBK technology in India, leading to formulation of strategy for large-scale dissemination.

Policy issues

The long-term prospects for the VSBK technology are very bright in the context of existing clamps and Bulls Trench Kilns. The BTK scale of production depends on assured availability of soil. Only entrepreneurs in possession of land in execess of three hectares would invest in permanent kiln structure, as required by environmental regulations. The land requirement of VSBK is only one hectare for five years of assured operation.

The unique selling proposition of the VSBK its energy efficiency. As the national policy moves toward full pricing of energy and energy costs soar, the financial viability of VSBK improve manifold against any other mode of brick production. The saving in CO2 emissions makes though VSBK highly efficient in the national context of lowering greenhouse gas emissions.

The environmental laws for improving air quality, particularly in peri-urban areas and areas where cash crops are grown, have been defined VSBK, in its present state of development, meets all the air quality norms. VSBK performance can be further improved through optimisation of the fuel characteristics. The future augurs well for the VSBK technology.

(The authors, who belongs to Development Alternatives would like to specially acknowledge the intellectual and financial support of the Swiss Agency for Development Co-operation, New Delhi. Continued technical support of the Henass Academy of Sciences, Zhengzhou, China, is highly appreciated.)

Table 2 : Specific emissions when coal is used as fuel

Table 3 : Techno-economic parameters of VSBK

Table 4 : Environmental performance - workplace concentrations