China Standard for Exhaust Gas Emissions from Natural Gas Tunnel Kilns


In recent years, with the growing concerns about environmental pollution and the need for sustainable development, countries around the world have been implementing stricter regulations on industrial emissions. China, as one of the largest producers of ceramics and other building materials, has also recognized the importance of reducing air pollutants emitted by kilns used in the production process. Today we will focus on the exhaust gas emissions from natural gas tunnel kilns and discuss the China standard that governs these emissions.


Natural gas tunnel kilns are widely used in the ceramic industry due to their energy efficiency and low operating costs compared to traditional coal-fired kilns. However, the combustion of natural gas still produces various pollutants, including nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOCs), and particulate matter (PM). These emissions not only contribute to air pollution but also to exacerbate climate change.

To address these concerns, the Chinese government has established standards for exhaust gas emissions from natural gas tunnel kilns. These standards aim to minimize the environmental impact of kiln operations while promoting sustainable development in the ceramic industry.

The current China standard for exhaust gas emissions from natural gas tunnel kilns is known as GB 31574-2015 "Emission Standard for Air Pollutants from Ceramic Industry." This standard sets specific limits on the concentration of various pollutants emitted during kiln operations.

Pollutant Limits

1. Nitrogen Oxides (NOx): The standard specifies a maximum limit of 50 milligrams per cubic meter (mg/m³) for NOx emissions. NOx is a major contributor to smog formation and can have detrimental effects on human health.

2. Carbon Monoxide (CO): CO emissions are limited to 100 mg/m³. CO is a toxic gas that can cause health problems, especially in enclosed spaces.

3. Volatile Organic Compounds (VOCs): The standard sets a maximum limit of 20 mg/m³ for VOC emissions. VOCs are hazardous air pollutants that can contribute to the formation of ground-level ozone and other harmful effects.

4. Particulate Matter (PM): The standard specifies a limit of 30 mg/m³ for PM emissions. PM refers to tiny particles suspended in the air, which can penetrate deep into the respiratory system and cause respiratory and cardiovascular problems.

To ensure compliance with the emission standards, kiln operators are required to install continuous emission monitoring systems (CEMS) to measure and record pollutant concentrations in real-time. These monitoring systems provide accurate emission data.

In addition to CEMS, regular inspections and audits are conducted by environmental authorities to verify compliance with the emission standards. Non-compliance can result in penalties, fines, or even suspension of kiln operations until necessary measures are taken to rectify the situation.

Benefits and Challenges

The implementation of the China standard for exhaust gas emissions from natural gas tunnel kilns brings several benefits to both the environment and the ceramic industry.

Environmental Benefits

1. Reduced Air Pollution: By limiting the release of harmful pollutants, the standard helps to improve air quality and reduce the impact on human health. This is particularly important in densely populated areas where kilns are often located.

2. Climate Change Mitigation: Natural gas combustion produces less carbon dioxide (CO2) compared to coal-fired kilns. By encouraging the use of natural gas and regulating its emissions, the standard contributes to mitigating climate.

Industry Benefits

1. Enhanced Reputation: Compliance with emission standards demonstrates a commitment to environmental responsibility, improving the reputation of ceramic manufacturers and their products in both domestic and worldwide.

2. Technological Advancement: The need to meet emission standards encourages the development and adoption of cleaner and more efficient kiln technologies. This drives innovation and improves overall industry.

While the China standard for exhaust gas emissions brings significant benefits, it also poses challenges for some kiln operators, especially smaller businesses. Upgrading existing kilns to meet the emission limits may require substantial investments in equipment and technology. However, these challenges can be overcome with government support, incentives, and technological advancements that make cleaner kiln technologies more affordable and accessible.

The China standard for exhaust gas emissions from natural gas tunnel kilns represents a crucial step towards reducing air pollution and promoting sustainable development in the ceramic industry. By setting specific limits on pollutants and enforcing compliance through monitoring and inspections, the standard ensures that kiln operations are conducted in an environmentally responsible manner. While challenges exist, the benefits of improved air quality, climate change mitigation, and industry advancement outweigh the initial costs of implementation. As China continues to prioritize environmental protection, the ceramic industry will play a vital role in adopting cleaner technologies and contributing to a greener future.