Hydrogen sulfide is an acute toxic substance, and inhalation of a small amount of high concentration hydrogen sulfide in a short time can be fatal. Low concentration of hydrogen sulfide has effects on eyes, respiratory system and central nervous system.
Properties and stability: Soluble in organic amine. It also has great solubility in caustic solution. Combustion in excess oxygen generates sulfur dioxide and water, and when oxygen supply is insufficient, water and free sulfur are generated. Stable at room temperature. Soluble in water, the aqueous solution is weakly acidic, and it will slowly become turbid due to oxidation and precipitation of sulfur when it comes into contact with air.
It can burn in the air to produce blue flame and generate SO2 and H2O, and when the air is insufficient, it will generate S and H2O. Highly toxic, even diluted H2S can irritate respiratory tract and eyes and cause headache. When the concentration reaches 1mg/L or higher, it is dangerous to life, so the preparation and use of H2S should be carried out in a fume hood.
Extended data:
preventive measure
1. The production equipment that produces hydrogen sulfide should be sealed as much as possible, and an automatic alarm device should be set (the concentration of hydrogen sulfide in dangerous places cannot be judged according to the smell, and when the hydrogen sulfide reaches a certain concentration, it will lead to olfactory paralysis).
2. Waste water, waste gas and waste residue containing hydrogen sulfide should be purified and discharged up to standard.
3. When entering the workplaces where hydrogen sulfide may exist, such as closed containers, pits, kilns, ditches, etc., the concentration of hydrogen sulfide in the air in this place should be determined first, and ventilation and detoxification measures should be taken to ensure safety before operation.
4. The concentration of hydrogen sulfide in the air of hydrogen sulfide working environment should be determined regularly.
5. Personal protective measures should be taken during operation, and gas masks should be worn. The waist of the worker should be tied with a life-saving belt or rope. Do a good job of mutual insurance, with more than two people present, and immediately rescue the poisoned person in case of abnormal situation.
6. People suffering from hepatitis, kidney disease and tracheitis shall not engage in the operation of contacting with hydrogen sulfide.
7. Strengthen the training of employees' relevant professional knowledge and improve their awareness of self-protection.
8. Install hydrogen sulfide treatment equipment.
Matters needing attention in various industries:
1. Matters needing attention in sampling operation
(1) Check whether the sampler is in good condition;
(2) Wear a proper gas mask, stand in the upwind direction, and be supervised by a special person;
(3) When sampling, the manual valve should be opened slowly, and don't beat the valve with a wrench.
2. Matters needing attention in water cutting operation
(1) Wear a proper gas mask, be supervised by a special person, and stand upwind;
(2) There should be a certain distance between the dewatering incision and the dewatering opening;
(3) The released acid gas should be neutralized with calcium hydroxide or sodium hydroxide solution, and isolation measures should be taken to prevent passers-by from poisoning;
(4) Personnel shall not leave the site during dehydration to prevent a large amount of acid gas from escaping.
3, equipment maintenance work
Need to enter the equipment and containers for maintenance, generally after purging, replacement, adding a blind plate, sampling analysis qualified, handling equipment and containers safety operation ticket, can enter the operation. However, some equipment containers need to be dismantled manually before maintenance, and hydrogen sulfide, oil and gas and other toxic and harmful gases will be emitted during cleaning, so safety measures must be taken. The following seven items are the steps of equipment maintenance:
(1) Formulate the construction plan;
(2) Operators have received safety technical training;
(3) Wear a proper gas mask and carry a safety belt (rope);
(4) Before entering the equipment container, sampling and analysis must be carried out;
(5) the operation time should not be too long, generally not more than 30min；;
(6) handle the safety operation ticket;
(7) The construction process shall be supervised by special personnel, and medical personnel shall be present when necessary.
4, into the sewer (well), pipe trench operation
(1) Implement Safety Protection Regulations for Limited Space Operation;
(2) control the dehydration and condensation of various substances entering the sewer;
(3) Adopt forced ventilation or natural ventilation to ensure that the oxygen content is more than 20%;
(4) Wear a gas mask;
(5) Carry a safety belt (rope);
(6) handle the safety operation ticket;
(7) When working underground in the sewer, special personnel shall be assigned for supervision and keep close contact with the ground.
5, oil pool cleaning operation
(1) Before cleaning the lower sump, dirty oil and sewage must be pumped clean and washed with high-pressure water for replacement;
(2) Sampling analysis, and determining the safety measures of the construction scheme according to the measurement results;
(3) Wear a suitable gas mask, be supervised by a special person, and wear a safety belt (rope) when necessary;
(4) handle the limited space operation ticket.
6, plugging, disassembly or installation work
When blocking, dismantling or installing equipment, containers and pipelines containing H2S materials, it is necessary to:
(1) Strictly control the operation under pressure, close the valve connected with the equipment container, and eliminate the residual pressure;
(2) Wear a proper gas mask and be supervised by a special person;
(3) When removing the flange screws, do not remove all the screws first and then loosen them, so as to avoid a large number of toxic gases pouring out.
References:
Baidu encyclopedia-hydrogen sulfide