Automatic Coal Feeder

Brick Kiln Worker (Fireman) manually feeding coal into kiln porthole

Automatic Coal Feeder: Refining a technology to reduce black carbon emissions from South Asian brick kilns

Objectives

1. Develop an Automatic Coal Feeder: completed by the BUET Engineering team in Dhaka, with the support of Stanford engineers.

2. Revise the Stanford student-developed automatic coal feeder prototype based on the input from initial users on brick kilns in Bangladesh

3. Engage with local shops in Bangladesh to manufacture the automatic coal feeder

4. Develop a demonstration kiln that feeds coal entirely using automatic coal feeders

5. Explore interest in the coal feeders among neighboring kilns

Rationale

Bricks are an essential building material for the growing economy in Bangladesh and other countries in South Asia. In Bangladesh ~7,000 brick kilns produce 27 billion bricks each year, generating 11% of the country’s particulate matter, 22% of black carbon, and 17% of total annual CO2 emissions. Each year the global radiative forcing generated by the black carbon and greenhouse gases from brick kilns across South Asia is equivalent to the climate impact from the entire US passenger car fleet. Exposure to air pollutants contributes to morbidity, mortality and adverse birth and cognitive outcomes. Recent estimates suggest that air pollution generated by brick kilns results in over 6,000 premature adult deaths annually in Bangladesh.

Over the last 15 years the primary strategy to reduce pollution from brick kilns in Bangladesh has been to move the sector away from traditional brick kilns that cost approximately $80,000 to build and transition to modern automated kilns that cost approximately $1 million to build. Modern kilns produce machine molded bricks of consistent quality and burn coal more efficiently, markedly reducing pollution. A few modern kilns have been established in Bangladesh, often with funding from the World Bank, but the bricks produced by these kilns cost 40% more than the bricks produced by traditional kilns and so have never accounted for over 10% of the total market.

We have been working with traditional brick kiln owners in Bangladesh to introduce low-cost interventions that would reduce heat loss and improve combustion efficiency. These interventions include adding additional layers of ash to improve insulation and stacking bricks differently for better distribution of air and heat through the kiln. These interventions reduce the amount of coal burned per brick produced. This reduces both pollution and coal costs. Because coal is their single greatest business expense, these interventions are compatible with brick manufactures’ incentives. In a pilot study promoting these interventions we found 75% of kiln owners adopted these modest improvements.

Working with existing brick manufacturers to improve the energy efficiency of production provides an opportunity to improve the dominant production model, and achieve immediate reductions in air pollution and greenhouse gas emissions. Such improvements are critically important in Bangladesh, which experiences some of the world’s worst air quality and is among the most vulnerable countries to the impacts of climate change.

Project Dates

2021-2024

Stage of Work

Currently, kiln-workers feed coal manually into kiln porthole-feeders. This project looks to replace manual feeding with an automated coal feeder (funnel and motor). Automation tests revealed the problem of wet coal clogging the feeder. (Coal becomes wet because of humidity, rain, or of being watered down to reduce dust).

We have completed the Development stage (designing an intervention to interrupt the causal pathway), and are now preparing for the Pilot stage (implementing, assessing and iterating the intervention).

Accomplishments:

1. Development of two automated coal feeder designs: one by the Stanford Mechanical Engineering team, and one by Bangladesh University of Engineering and Technology (BUET); designed to address two problems, that of wet-coal clogging, and of low-powered motors (motors get heated with the volume/speed of the coal load).

2. BUET then built prototypes of both (Stanford and BUET) designs.

3. The Stanford team traveled to Bangladesh and worked alongside postdoc Moogdho Mahzab and BUET Engineers to test the prototypes on kilns in Jessore (Jashore).

4. Teams met with Kiln Owners/Managers; convinced them to run the prototypes for several whole-day-periods; and discussed with Kiln Owners the incentives for adopting this intervention (increased efficiency of coal usage, lower cost of production, reduced labor time).

Next focus: Addressing the remaining issues of wet coal clogging and motor-power; and piloting the prototypes on 20 kilns in Jessore, running them for the next kiln season (November 2023 through May 2024).

People

Primary Contact: Moogdho Mahzab

Stanford University

. Stephen Luby

. Grant Miller

. Jeffrey Wood (ME 170: Mechanical Engineering Design- Integrating Context with Engineering)

Bangladesh University of Engineering and Technology (BUET)

. Prof. Shoeb Ahmed (Dept. of Chemical Engineering)