Industry background:
In recent years, various chemical and hazardous chemical industries have experienced frequent safety accidents, resulting in a large number of casualties and property losses among workers. The accidents involved mainly include gas leaks, poisoning and suffocation, chemical explosions, physical explosions, and fire accidents. The danger and hazards of flammable, explosive, and toxic gases are commonly present in the energy and chemical industry, and this phenomenon is determined by the inherent characteristics of the industry itself. The large amount of raw materials, intermediates, and products processed by most chemical enterprises have flammable, explosive, and toxic properties; The processes of chemical production, storage, and transportation are often under extremely flammable and explosive conditions such as heating (or low temperature), pressurization (or negative pressure), catalysis, and chemical reactions, and are prone to volatilizing flammable, explosive, and toxic gases. Therefore, explosion prevention and toxic gas prevention play a particularly important role in energy and chemical safety.

Solution:
Monitoring locations: Graphitization workshop, acid treatment workshop, purification workshop, carbonization workshop, nitrogen production workshop, etc.
Monitoring gases: methane, hydrogen sulfide, oxygen, carbon monoxide, hydrogen chloride, hydrogen fluoride, and other gases.
Data transmission: Determine the number of gas detection alarm devices installed in each monitoring area based on the on-site situation. All detectors have real-time data display and sound and light alarm functions. The relevant gas concentration values detected by the detectors in each workshop are transmitted to the gas alarm controller in the nearest transmission room through RS485 bus system. When any monitored gas concentration reaches the alarm value, the nearby fan will be automatically started through a relay for air circulation treatment. At the same time, the corresponding channel of the gas alarm controller in the transmission room will also give an alarm prompt.

Scheme composition:
Gas detection alarm, gas alarm controller, shielded cable, hub, switch PLC、DCS、 Client gas online monitoring software platform, monitoring center monitoring platform system, etc.

Norms or industry standards for implementing the plan:
Design Code for Electrical Installations in Explosive and Fire Hazardous Areas GB 50058-92
Code for Construction and Acceptance of Industrial Automation Instrumentation Engineering GBJ 93-86
Design Specification for Signal Alarm and Interlocking Systems in Petrochemical Enterprises (SH 3018-1990)
Technical Code for Construction of Instrumentation Engineering in Petrochemical Industry (SH 3521-1999)
Design Specification for Combustible Gas and Toxic Gas Detection and Alarm in Petrochemical Industry GB50493-2009
Technical Requirements and Test Methods for Combustible Gas Alarm Controllers GB16808-2008
General Technical Conditions for Gas Detection and Alarm Devices in Work Environment GB12358-2006
Electrical Equipment for Explosive Gas Environments Part 1: General Requirements GB3836.1-2010
Electrical Equipment for Explosive Gas Environments Part 2: Explosion proof Type "d" GB3836.2-2010